Circuit idea: Making constant-voltage and constant-current nonlinear resistors overact.
The negative differential resistance is closely related to the true negative resistance. To see the close connection between them, a lot of reciprocal links are placed inside the two stories.
An S-shaped current-controlled negative differential resistor (e.g., a neon lamp) exhibits negative resistance in the middle region (red) of its IV curve where an increase in the current results in a decreased voltage. The instant ohmic resistance is still positive.
An N-shaped voltage-controlled negative differential resistor (e.g., a tunnel diode) exhibits negative resistance in the middle region (red) of its IV curve where an increase in the voltage results in a decreased current. The instant ohmic resistance is still positive as above.
3.2.1 How the negative resistor "jumps"
3.2.4 Where is the negative resistance during the "jump"?
5.1.2.1 What does amplification actually mean?
If we increase the voltage across an ordinary ohmic resistor, the current flowing through it increases proportionally according to Ohm's law (IOUT = VIN/R). Also, if we increase the current through the resistor, the voltage across it increases as well (VOUT = IIN.R). Thus the voltage and the current change in the same directions. But there are mysterious two-terminal electronic components (negative differential resistors, shortly NDR), having just the opposite behavior in the middle part of their IV curves - the voltage across and the current through them change in opposite directions. Some of them - neon lamps, thyristors, have an S-shaped IV curve while other - tunnel, Gunn and lambda diode, have an N-shaped IV curve (see the pictures on the top).
Although the negative differential resistance seems to be a mystic phenomenon, it is actually based on an extremely simple, clear and intuitive trick - the great dynamizing idea that is brought here to the utmost degree. A differential negative resistor is nothing more than a kind of "self-varying", dynamic resistor that changes extremely its instant (ohmic, chordal) resistance depending on the current passing through the resistor or on the voltage applied across it; thus a differential negative resistor is actually an over-dynamic resistor..
Negative differential resistors are dynamic but still positive resistors. They have different kinds of resistance in the three parts of their IV curves (located in the 1st or the 3th quadrant) - "positive" in the end parts and negative in the middle part. The three parts form the whole IV curve that, depending on the NDR behavior in the middle part, can be S- or N-shaped. When the input quantity (no matter current or voltage) increases, the S-shaped NDR decreases while the N-shaped NDR increases its instant resistance.
Depending on the proportion between the negative differential resistance and the "positive" resistance of the input source, both the negative resistors can operate either in a linear or a bi-stable mode. When operating in a linear mode, they change gradually their instant resistance in the negative resistance region while in a bi-stable mode they do it sharply (jump over it).
Each of the two NDR can be driven both by voltage and current. To operate in a linear mode, an S-shaped NDR has to be driven by current while an N-shaped NDR - by voltage; v.v., to operate in a bi-stable mode, an S-shaped NDR has to be driven by voltage while an N-shaped NDR - by current. So, in contrast to the widespread but misleading viewpoint, there are no particular current controlled (CCNR) and voltage controlled (VCNR) negative resistors - there are only S-shaped and N-shaped NDR, and each of them can be both current and voltage controlled.
In the middle negative resistance region, negative differential resistors behave as two-terminal active elements (such as transistors). They cannot be used independently; they need an additional power supply to be connected. Thus the combination of the negative differential resistor and the power supply can be considered as another kind of a true negative resistor (the other kind of a true negative resistor is a combination of a constant "positive" resistor and a varying voltage source). From another viewpoint, this combination can be thought as of an electrical source with negative internal resistance. It is a usual practice to think of a negative differential resistor as of a true negative resistor implicitly assuming the existence of a power supply.
We, circuit ideators:), know that the truth about circuit phenomena is hidden rather in the movement from simple to complex circuits (in the circuit evolution) than in the final perfect circuit solutions. So, the best way to reveal the NDR phenomenon is to show the metamorphosis of the negative differential resistor from the ordinary ohmic resistor to the sophisticated negative one, to show the evolution of the bare ohmic resistance... According to this idea, we can first reveal the secret of S-shaped negative resistors by following the succession of typical resistances in the order high ohmic > decreased > zeroed > S-shaped NDR. Then we can reveal the secret of the dual N-shaped negative resistors by a similar succession of other typical resistances - low ohmic > increased > infinite > N-shaped NDR. To visualize the resistor evolution, we will gradually draw the particular segments of the seesaw NDR IV curves and will explain how they are obtained. Note they are straight lines although the whole IV curves represent nonlinear resistances.
We can see many examples (analogies) of this arrangement in our routine, where we experience some opposition when implementing our purposes and someone unnoticely helps us. As a result, some kind of a "pressure" or a "flow" appears. A good example can be the plumbing analogy where you control the main water faucet and I control some sink faucet. Thus you control the water flow or pressure and I control the magnitude of the water impediment.
The best way to see how such weird electronic devices do these magics (when the voltage increases, the current decreases or when the current increases, the voltage decreases) is to place ourselves in their place and begin performing their functions, to emulate their behavior by an empathy. What does actually an NDR do? It just changes its instant ohmic resistance depending in some definite way on the input variable (voltage or current). Then how do we emulate it? Of course, simply by using a humble variable resistor (a rheostat) - fig. 1 and fig. 6. Let's do it as a funny game: you will control the input current source; I will control the rheostat (you are the source, I am the load:) Thus I and the rheostat combine to form a "man-controlled" negative differential resistor and you drive it.
To see the negative resistance regions in the IV curves of negative resistors, they have to operate in a linear mode (you will understand what this means later). For this purpose, we have to supply S-shaped negative resistors by a current source; you will understand why below. Otherwise, they will operate in the even more exotic bi-stable mode.
We can present graphically the circuit operation of the simple electrical circuit (a source connected to a load) shown in fig. 1 if we consider that the voltage across the two elements is the same and the current flowing through them is the same as well. For this purpose, we have to superimpose their IV curves on the same coordinate system: the IV curve of the variable resistor is a straight line beginning from the coordinate origin and with a slope depending on the instant resistance; the IV curve of the input current source is a horisontal line shifted from the X-axis. The intersection point A (alias operating point) represents the instant magnitudes of the current IA and the voltage VA.
Now connect a voltmeter across the resistor R and an ammeter in series with it to monitor the voltage and the current. Are you ready? Let's start the "game"!
Fig. 2. High constant (ohmic) resistance along the section 0-1.
In routine, when applying some kind of "flow" and experiencing a constant high impediment, the obtained "pressure" is proportional to our efforts. For example, imagine I have slightly opened the sink faucet in our plumbing analogy; so, if you begin opening more and more the main faucet to increase the water flow, the water pressure begins increasing quickly and proportionally to the water flow.
According to this life situation, in the beginning, I set the rheostat's slider in the end position (highest resistance R) and you begin increasing continuously the input current IIN. As a result, voltage drop VOUT appears across the resistor R. According to Ohm's law, it is proportional to the current passing through the resistor - VOUT = R.IIN. Note the voltage depends only on the current and the Ohm's law equation is a function of one variable.
On the graphical representation (fig. 2), when you vary the current IIN of the input current source, its (your) IV curve moves vertically remaining parallel to itself. As a result, the operating point A slides over the IV curve of the ohmic resistor R from point 0 to point 1 that is a straight line. The slope of the R IV curve represents graphically the value of the ohmic resistance R. It is a "static", constant, steady resistance as it does not depend on the location of the operating point A.
But there are many situations in our life where the contrary impediment changes when we implement our purposes. Imagine our antagonist has a unsteady behavior and decreases (inconspicuously for us) his/her initial high opposition. As a result, we have the illusion that the opposition has decreased; the "pressure" decreases as well. As an example, in the plumbing analogy, if I begin opening gradually the sink faucet when you open the main faucet to increase the water flow, the water pressure will increase lazier and you will have the feeling that the water resistance is decreased. But this is an illusion since it is not simply decreased; it is decreasing.
Fig. 3. Virtually decreasing the resistance along the section 1-2.
Let's now apply this clever dynamizing trick to decrease virtually the resistance R in such an exotic way. Imagine when you reach the point 1 (fig. 3), I decide to help you along the whole section 1-2. For this purpose, I begin moving slightly the slider to decrease gradually the rheostat's resistance. As a result, the voltage begins depending both on the current and the resistance. The Ohm's law equation becomes a function of two variables - VOUT = IIN1.RIN2.
This is the simple but clever dynamizing trick - if the input current IIN1 increases, the resistance RIN2 slightly decreases and their product VOUT increases slowly! You have the illusion that the resistance R has permanently decreased but actually, it is continuously decreasing and you see new, lower dynamic (differential) resistance dR1 < R. The "static" resistance R is converted into a smaller differential resistance dR1. "Bad" zeners and ordinary diodes have such property.
Now look at the picture (fig. 3) to see this trick in a more attractive way. When you increase the input current IIN from point 1 to point 2, its IV curve moves upward remaining parallel to itself. But as, at the same time, I decrease the resistance R, its IV curve rotates counterclockwise. As a result, the operating point A slides along a new more vertical IV curve, which represents the new dynamic resistance dR1 < R.
Now imagine that the dynamizing idea above is improved so that our antagonist decreases (again, inconspicuously for us) his/her opposition to such extent that we do not experience any impediment when implementing our purposes. The result is amazing: we have the illusion that the opposition has dissapeared, we realize our purposes without any efforts and the "pressure" stays constant! We can see this situation in our plumbing analogy. In this region, you continue opening the main faucet but now I am opening the sink faucet with the same rate of change. What a simple but clever idea - just change the flow and the impediment with the same rate but in different directions! The result is the same - the pressure stays constant and you have the feeling that there is no any impediment!
Fig. 4. Virtually zeroing the resistance along the section 2-3.
Then let's apply this trick to zero virtually the resistance R. Now imagine when you reach the point 2 (fig. 4), I begin moving vigorously enough the slider thus decreasing considerably the rheostat's resistance R so that, when in Ohm's law (VOUT = IIN1.RIN2) the input current IIN1 increases, the resistance RIN2 decreases with the same rate of change and their product VOUT stays unchangeable. You have the feeling that there is no resistance and the input current source is shorted. What a great idea! We have made a constant-voltage nonlinear resistor (a voltage stabilizer). All kinds of diodes (zener, LEDs, etc.), varistors and some circuits with parallel negative feedback (active diodes, active zeners, etc.) act in this way.
On the graphical representation (fig. 4), when you increase the input current IIN from point 2 to point 3, its IV curve moves upward as before. But I decrease vigorously enough the resistance R at the same time; so, its IV curve rotates rapidly enough contraclockwise. As a result, the operating point A slides upward from point 2 to point 3 along the vertical IV curve of the new dynamic resistance dR2 = 0.
Finally, imagine that the dynamizing idea is enormously reinforced so that our antagonist goes too far decreasing many times more his/her opposition than needed. The result is quite unexpected and surprising - we increase our efforts but the "pressure" does not increase or stay constant; instead imagine it even decreases! In the plumbing analogy, you are opening the main faucet but I am opening the sink faucet with a higher rate of change. What a wonderful trick - change the impediment more vastly than the input water flow and you will see that the water pressure goes down instead to rise!
Fig. 5. Making the resistance negative (creating S-shaped negative resistance) along the section 3-4.
If we put this idea in practice, we will manage to convert the ordinary "positive" resistance R into negative differential resistance. Practically, this means to make the constant-voltage nonlinear resistor overact, to go too far when changing its resistance. Well, let's do it. When you reach the point 3 (fig. 5), I begin moving extremely vigorously the slider thus decreasing enormously the rheostat's resistance R. The situation with Ohm's law (VOUT = IIN1.RIN2) becomes now extremely interesting - the input current IIN1 increases but the resistance RIN2 decreases more quickly and their product VOUT decreases! What a magic! You increase the input variable (the current) but the output variable (the voltage) decreases?!?!
Figuratively speaking, the two input variables (the current and the resistance) "fight" each other striving to change (in opposite directions) the output variable (the voltage). There are three situations: the first variable dominates; the two variables compensate each other; the second variable dominates. First, if the rate of the resistance change is smaller than the rate of the current change, the voltage only slowers its rate of change but continues increasing. Then, if the two rates are equal, the voltage does not change at all. Now the rate of the resistance change is bigger than the rate of the current change; so, the voltage begins decreasing. In electronics, thyristors and neon bulbs act in this way (in certain parts of their IV curves).
If you are observant enough, you can see the connection with the previous step thinking of the negative differential resistor as of an "over-acting" constant-voltage nonlinear resistor.
In the graphical representation (fig. 5), when you increase the input current IIN from point 3 to point 4, its IV curve moves upward as usual. But now, as I decrease extremely vigorously the resistance R at the same time, its IV curve rotates enormously rapidly counterclockwise. As a result, the operating point A slides upwards from point 3 to point 4 over the IV curve of the new negative differential resistance dR3 < 0. It is inclined (folded up) to the left and has a negative slope.
Unfortunately, there are no unlimited things in this world:( So, at point 4 (fig. 5), we have already exhausted a great part of the initial resistance and begin slowing the rate of change. Thus we can create again zero, decreased and finally, ohmic resistance. The IV curve folds up clockwise and resembles the letter "S".
S-shaped negative differential resistor is an overacting constant-voltage nonlinear resistor.
When the current through an S-shaped NDR increases, it decreases enormously its instant ohmic resistance so that the voltage across it decreases.
An S-shaped NDR starts with high initial resistance (to decrease the resistance it has to have what to decrease:) and finishes with low final resistance.
Once we revealed the secret of the S-shaped NDR, let's unveil, in the similar way, the mystery of the dual N-shaped NDR.
Fig. 6. A setup for emulating an N-shaped negative differential resistor.
To operate in a linear mode, we have to supply N-shaped negative resistors by a voltage source; otherwise, they will operate in the exotic bi-stable mode. So, to emulate an N-shaped negative differential resistor, we can use the same setup as in the fig. 1 only if we replace the current source with a voltage one - fig. 6. As above, the voltage across and the current through the two elements is the same; so we may superimpose their IV curves on the same coordinate system. The IV curve of the variable resistor is again a straight line beginning from the coordinate origin and with a slope depending on the instant resistance but the IV curve of the input voltage source is a vertical line shifted from the Y-axis. The operating point A represents the instant magnitudes of the current IA and the voltage VA.
In routine, when applying some kind of "pressure" and experiencing a constant low impediment, the obtained "flow" is proportional to our efforts (a life manifestation of Ohm's law). For example, imagine I have vastly opened the sink faucet in our plumbing analogy; so, if you begin opening more and more the main faucet to increase the water pressure, the water flow begins increasing quickly and proportionally to the pressure (a hydraulic manifestation of Ohm's law).
Fig. 7. Low constant (ohmic) resistance along the section 0-1.
According to this life situation, in the beginning, I set the rheostat's slider (fig. 6) in the end position according to the lowest resistance R and you begin increasing continuously the input voltage VIN. As a result, current IOUT appears across the resistor R. According to Ohm's law, it is proportional to the voltage applied across the resistor - IOUT = VIN/R.
On the graphical representation (fig. 7), when you vary the voltage VIN of the input voltage source, its (your) IV curve (red colored) moves horizontally. As a result, the operating point A slides over the IV curve of the ohmic resistor R from point 0 to point 1 that is a straight line. The slope of R IV curve represents graphically the value of the ohmic resistance R. It is "static", constant, steady resistance as it does not depend on the location of the operating point A.
Remember the situations in our life when the contrary impediment changes when we implement our purposes. Now imagine the "antagonist" begins increasing (inconspicuously for us) his/her initial low opposition. As a result, we have the illusion that the opposition has increased and the "flow" decreases. In the plumbing analogy, if I begin closing gradually the sink faucet when you open the main faucet to increase the water pressure, the water flow will increase lazier and you will have the feeling that the water resistance is increased.
Fig. 8. Virtually increasing the resistance along the section 1-2.
Let's apply the dynamizing trick now to increase virtually the resistance R. Imagine when you reach the point 1 (fig. 8), I begin moving slightly the slider to increase gradually the rheostat's resistance. As a result, the current begins depending both on the voltage and the resistance. The Ohm's law equation becomes a function of two variables - IOUT = VIN1/RIN2.
Now if the input voltage VIN1 increases, the resistance RIN2 slightly increases and their ratio VOUT/RIN2 increases slowly! You have the illusion that the resistance R has permanently increased but actually, it is continuously increasing and you see new, higher dynamic (differential) resistance dR1 > R. The "static" resistance R as though is converted into higher differential resistance dR. In this way we can explain what a nonlinear resistor is - we can think of it as of a dynamic linear (ohmic) resistor. For example, incandescent light bulbs have such property in certain part of their IV curves.
Now look at the picture (fig. 8) to see this trick in a more attractive way. When you increase the input voltage VIN1 from point 1 to point 2, the vertical IV curve of the input voltage source moves from left to right remaining parallel to itself. But as, at the same time, I increase the resistance R, its IV curve rotates clockwise. As a result, the operating point A slides along a new more inclined to the right IV curve, which represents the new dynamic resistance dR1 > R.
Now imagine that the dynamizing idea above is enforced so that our antagonist increases (again, inconspicuously for us) his/her opposition to such extent that we experience infinite impediment when implementing our purposes. The result is amazing: we have the illusion that the opposition has become infinite, we cannot realize our purposes at all and the "flow" stays constant! Let's see this situation in the plumbing analogy. In this region, you continue opening the main faucet but now I am closing the sink faucet with the same rate of change. Another clever idea - just change the pressure and the impediment with the same rate and in the same directions! Then the flow stays constant (there is a flow but there is no change of the flow).
Fig. 9. Making infinite resistance along the section 2-3.
We can strenghten the dynamizing idea above to the extent to make the resistance R virtually infinite. For this purpose, when you reach the point 2 (fig. 9), I begin moving vigorously enough the slider to increase considerably the rheostat's resistance R so that, when in Ohm's law (IOUT = VIN1/RIN2) the input voltage VIN1 increases, the resistance RIN2 increases with the same rate of change and their ratio VIN1/RIN2 stays unchangeable. As a result, you have the feeling that the circuit is open and the input voltage source is unloaded. Another great idea! We have made a constant-current nonlinear resistor (a current stabilizer). The output parts (collector-emitter, drain-source) of all kinds of transistors (bipolar, FET, MOS, etc.), tubes and resettable fuses act in this way.
On the graphical representation (fig. 9), when you increase the input voltage VIN1 from point 2 to point 3, the vertical IV curve of the input voltage source continues moving from left to right as before. But I increase vigorously enough the resistance R at the same time; so, its IV curve rotates rapidly enough clockwise. As a result, the operating point A slides from point 2 to point 3 along the horizontal IV curve of the new dynamic resistance dR2 = ∞.
In the middle of our "excursion" along the IV curve, imagine that the dynamizing idea is enormously reinforced so that our antagonist goes too far increasing many times more his/her opposition than needed. The result is very, very surprising - we increase our efforts but the "flow" does not increase or stay constant; instead, it decreases as the pressure above! In the plumbing analogy, you are opening the main faucet but I am firmly closing the sink faucet with a higher rate of change. Another wonderful trick - increase the impediment more vastly than the input water pressure increases and you will see that the water flow goes down instead to rise!
Fig. 10. Making the resistance negative (creating N-shaped negative resistance) along the section 3-4.
Let's apply this idea in the electricity. If we make the constant-current nonlinear resistor overact, we will manage to convert in another way the ordinary "positive" resistance R into negative but N-shaped differential resistance. Let's do it. When you reach the point 3 (fig. 10), I begin moving extremely vigorously the slider to increase enormously the rheostat's resistance R. The situation with Ohm's law (IOUT = VIN1/RIN2) becomes again extremely interesting - the input voltage VIN1 increases but the resistance RIN2 increases more quickly and their ratio VIN1/RIN2 decreases! Another magic! You increase the input variable (the voltage) but the output variable (the current) decreases again! Let's scrutinize this situation as above.
The two input variables (the voltage and the resistance) "fight" each other striving to change the output variable (the current). There are three situations again. First, if the rate of the resistance change is smaller than the rate of the voltage change, the current only slowers its rate of change but continues increasing. Then, if the two rates are equal, the current stays constant. Finally (this case), the rate of the resistance change is bigger than the rate of the voltage change and the current begins decreasing. In electronics, tunel diode, Gunn diode and lambda diode act in this way (in certain parts of their IV curves).
If you are observant again, you can see a connection with the previous step thinking of this kind of a negative differential resistor as of an "over-acting" constant-current nonlinear resistor.
On the graphical representation (fig. 10), when you increase the input voltage VIN1 from point 3 to point 4, the vertical IV curve of the input voltage source continues moving from left to right as before. But as I increase extremely vigorously the resistance R at the same time, the resistor's IV curve rotates enormously rapidly clockwise. As a result, the operating point A slides downwards from point 3 to point 4 over the IV curve of the new negative differential resistance dR3 < 0. As in the case of the "decreasing" (S-shaped NDR), it has a negative slope but now it is inclined (folded up) to the right.
Remember again there are no unlimited things in our world:((( As above, at point 4 (fig. 8), we are already exhausted a great part of the initial high conductance (the other name of "low resistance":) and begin slowing the rate of change. Thus we can create infinite, decreased and finally, ohmic resistance. The IV curve folds up counterclockwise and resembles the letter "N".
N-shaped negative differential resistor is an overacting constant-current nonlinear resistor.
When the voltage across an N-shaped NDR increases, it increases enormously its instant ohmic resistance so that the current through it decreases.
An N-shaped NDR starts with low initial resistance (to increase the resistance it has to have what to increase:) and finishes with high final resistance.
The ordinary "positive" resistance and the negative differential resistance are closely related - negative differential resistance is created on the base of positive resistance, simply by modifying it dynamically. Since there is no internal source, an NDR IV curve always starts from the coordinate origin (0,0). This means if the voltage applied across an N-shaped NDR is zero, the current through it is zero as well and v.v., if the current passed through an S-shaped NDR is zero, the voltage across it is zero again.
Note the NDR cannot occupy the whole IV curve; we can create a negative slope only in some limited middle part of the whole IV curve of a positive resistor (in the end parts, the NDR saturates and the resistance becomes positive; thus the odd "S" or "N" shape). For this purpose, we have somehow to change the monotonous motion of the operating point (that draws the IV curve) when the input quantity (voltage or current) changes within the negative resistance region; we have to change its direction back to front; we have to fold up the curve.
To picture this situation in a more colorful and empathic way, let's put ourselves in the place of the operating point and begin travelling from the coordinate origin:) When reaching the first key point, we decide to turn: in the case of an S-shaped NDR, we have to turn to the left (countercklockwise); in the case of an N-shaped NDR, we have to turn to the right (clockwise). But how do we "turn" back? How do we fold up the curve?
The trick is simple but clever: in the one-variable function IOUT = VIN/R or VOUT = IIN.R (Ohm's law) we begin changing the resistance as a second variable simultaneously with the first one. Thus, in this region, we actually have a function of two variables (IOUT = VIN1/RIN2 or VOUT = IIN1.RIN2) but we continue considering it as a function of one variable (we see only the one variable - the input voltage or current). Usually, the resistance is a function of the input quantity - R = R(VIN) or R = R(IIN); so we have a compound function IOUT = VIN/R(VIN) or VOUT = IIN.R(IIN). The whole trick is that we are misled - seeing only the straight line of the negative resistance region, we have the feeling that we see an ordinary but only changed (decreased/increased, zeroed/infinite or negative) ohmic resistance. But this is an illusion since we actually investigate not constant but varying ohmic resistor; we see dynamic but we think we continue seeing constant resistance! So, if we look at the whole curve, we will see that the continuation of the line does not pass through the coordinate origin. Thus we have artificially changed the resistance in this region; we have made dynamic resistance. As a result, the curve changes its slope up to negative but only within the borders in the negative resistance region where we have what (resistance) to change.
Let's now return to the negative differential resistance. After the end of the region, the reserve of high resistance (S-shaped curve) or high conductance (N-shaped curve) is depleted and the resistance reaches its minimum (S-shaped curve) or maximum (N-shaped curve). The magic of negative resistance ceases and the ordinary positive resistance establishes in the final part of the IV curve (the negative resistor is saturated). More colorfully, at this second key point, we decide to turn back: now, in the case of an S-shaped NDR, we have to turn to the right (cklockwise); in the case of an N-shaped NDR, we have to turn to the left (counterclockwise). For this purpose, we slow the rate of the resistance change and finally stop changing it at all; our "trip" is finished.
Negative differential resistance is created in some limited region of the resistor IV curve by vigorously changing its instant resistance.
Above we have driven the negative differential resistor with resistance RNE by a perfect current source with infinite internal resistance (RG = ∞) or by a perfect voltage source with zero internal resistance (RG = 0). In the general case, the NDR is driven by a real voltage source with some internal resistance RG. It is interesting fact that the negative differential resistor has a different behavior depending on the proportion between the magnitudes of the input positive resistance RG and the negative resistance RNE; i.e., it can operate in two different modes - linear and bistable.
In this mode, there is only one intersection point of the two superimposed IV curves (of the input source and of the NDR). The IV characteristic is a single-valued function and the output quantity is proportional to the input one.
Fig. 11a: An S-shaped IV curve (blue) of a current-driven NDR.
To operate in a linear mode, an S-shaped NDR should be driven by a high-resistive enough input source with internal resistance RG > RNE; in the extreme case, this is a perfect current source with infinite RG. In Fig. 11a, the operating point A is represented by the intersection point of two superimposed IV curves: the green one of the input current source IIN and the orange one of the NDR (dynamic positive resistor R).
When the input current varies from zero to maximum, an S-shaped NDR keeps up high ohmic resistance in the first part. In the negative resistance region, it behaves as a dynamic resistor that enormously decreases its ohmic (chordal) resistance from high to low; so, its IV curve rotates counterclockwise and the operating point C moves up and pictures the negative resistance part of the curve. In the last part, it has low ohmic resistance. And v.v., when the input current returns from maximum to zero, an S-shaped NDR begins with low ohmic resistance in the last part; in the negative resistance region, it behaves as a dynamic resistor that enormously increases its ohmic resistance from low to high, and in the first part, it has high ohmic resistance again.
Fig. 11b: An N-shaped IV curve (blue) of a voltage-driven NDR.
To operate in a linear mode, an N-shaped NDR should be driven by a low-resistive enough input source with internal resistance RG < RNE; in the extreme case, this is a perfect voltage source with RG = 0. In Fig. 11b, the operating point A is represented by the intersection point of two superimposed IV curves: the red one of the input voltage source VIN and the orange one of the NDR (dynamic positive resistor R).
When the input voltage varies from zero to maximum, an N-shaped NDR keeps up low positive resistance in the first part. In the negative resistance region, it behaves as a dynamic resistor that enormously increases its ohmic (chordal) resistance from low to high; so, its IV curve rotates clockwise and the operating point C moves down and pictures the negative resistance part of the curve. In the last part, it has high positive resistance. V.v., when the input voltage returns from maximum to zero, an N-shaped NDR keeps up high positive resistance in the last part; in the negative resistance region, it behaves as a dynamic resistor that enormously increases its ohmic resistance from high to low, and in the first part, it has low positive resistance again.
How the negative resistor "jumps"
Note the negative differential resistor is an exotic 2-terminal amplifying element since its output and input are inherently connected to each other; they are just the same! So, there is an intrinsic feedback in this device. Let's see why.
Beginning from the one end value (one of the ends of the negative resistance region) the negative resistor "is looking for" the equilibrium point (it has to be an intersection point between the two IV curves). For this purpose, it changes vigorously its instant (chordal) resistance looking for the equilibrium point but... it does not find it somewhere on the negative resistance part. Instead, it recedes further and further from the equilibrium point in an avalanche-like manner and finally, when the negative resistance region finishes, it reaches the equilibrium point somewhere on the other positive resistance part of the curve. Thus the NDR momentarily "jumps" from the one to the other positive part running quckly the negative area (the S-shaped NDR "jumps" vertically; the N-shaped NDR "jumps" horizontally).
To show in detail the mechanism of operation, two separate graphs are presented for the cases of increasing (Fig. 12a and 13a) and decreasing (Fig. 12b and 13b) input quantity. If you superimpose the two partial curves, they will represent the whole hysteresis curves for S-shaped (Fig. 12) and N-shaped (Fig. 13) negative resistors.
To operate in a bistable mode, an S-shaped NDR should be driven by a low-resistive enough input source with internal resistance RG < RNE; in the extreme case, this is a perfect voltage source with RG = 0.
Fig. 12a: An IV curve (blue) of an S-shaped NDR driven by increasing voltage (red).
Increasing voltage. When the input voltage varies from zero to maximum (Fig. 12a), the S-shaped NDR keeps up high ohmic resistance in the first part. In the middle part, when increasing voltage reaches VH, it decreases momentarily its instant (chordal) resistance from high to low. Its IV curve (orange) rotates counterclockwise while the voltage source IV curve stays immovable... then what is the trajectory of the operating point A? Let's try to guess - it moves up ("jumps up") along the voltage source IV curve and pictures this vertical part of its IV curve. Thus during the jump, the current increases instantly (jumps up) but the voltage stays constant (see more about the jump below). In the last part, the NDR has low ohmic resistance.
Fig. 12b: An IV curve (blue) of an S-shaped NDR driven by decreasing voltage (red).
Decreasing voltage. When the input voltage varies back from maximum to zero (Fig. 11b), the S-shaped NDR keeps up low positive resistance in the last part. In the middle part, when decreasing voltage reaches VL, it increases momentarily its ohmic (chordal) resistance from low to high. Its IV curve rotates clockwise; the operating point A moves down along the voltage source IV curve and pictures this vertical part of the curve. During the jump, the current decreases instantly (jumps down) but the voltage stays constant. In the last part, the NDR has high positive resistance.
To operate in a bistable mode, an N-shaped NDR should be driven by a high-resistive enough input source with internal resistance RG > RNE; in the extreme case, this is a perfect current source with infinite RG.
Fig. 13a: An IV curve (blue) of an N-shaped NDR driven by increasing current (green).
Increasing current. When the input current varies from zero to maximum (Fig. 13a), an N-shaped NDR behaves as follows. In the first part, it keeps up low positive resistance. In the middle part, when increasing current reaches IH, it increases momentarily its ohmic (chordal) resistance from low to high. Its IV curve rotates clockwise; the operating point A moves from left to right along the current source IV curve and pictures this horizontal part of the curve. During the jump, the voltage decreases instantly (jumps up) but the current stays constant (see more about the jump below). In the last part, it has high positive resistance.
Fig. 13b: An IV curve (blue) of an N-shaped NDR driven by decreasing current (green).
Decreasing current. When the input current varies back from maximum to zero (Fig. 13b), the N-shaped NDR keeps up high positive resistance in the last part. In the middle part, when decreasing current reaches IL, it decreases momentarily its ohmic (chordal) resistance from high to low. Its IV curve rotates counterclockwise; the operating point A moves from right to left along the current source IV curve and pictures this horizontal part of the curve. During the jump, the voltage decreases instantly (jumps down) but the current stays constant. In the first part, it has low positive resistance.
Where is the negative resistance during the "jump"?
You probably already are looking for the negative resistance region (section 3-4) on the NDR IV curve and do not find it. Where is it? As though it has dissapeared and the operating point A slides along the source's IV curve; it cannot move along the negative resistance section. To see why, let's consider a voltage controlled S-shaped NDR (fig. 12a). In this case, the operating point cannot move back along the section 3-4 (the voltage cannot go down) since the voltage source keeps up a constant voltage across the resistor during the "jump". But the negative resistor has somehow to get to the other stable point; it has to find a path to this point... and it passes over the voltage source IV curve (a vertical line). Similarly, in the case of a current controlled N-shaped NDR (fig. 13a), the operating point cannot move back along the section 3-4 (the current cannot go down) since the current source passes now a constant current through the resistor during the "jump". To get to the other stable point, the NDR has to find a path to this point... and it passes over the horizontal current source's IV curve.
During the "jump", the negative differential resistor is not a negative resistor!
It is a powerful idea to see the great feedback phenomenon in the operation of negative differential resistors. Looking from this well-known viewpoint at these mysterious elements, we can understand better their odd behavior. Let's do it!
Linear mode. What does a negative resistor do when operating in a linear mode (RG > RNE for an S-shaped NDR and RG < RNE for an N-shaped NDR)? It just keeps up the operating point on the negative resistance part of its IV curve. To see how it does this magic, look again at fig. 11 and imagine what happens when the input source changes its quantity. To deep in the NDR operation, assume that the negative resistor is too slow and lazy (as a human being:) and cannnot react instantly to the change.
When the input quantity sharply increases, the source IV curve moves and the operating point slides along the immovable IV curve of the chordal (instant, ohmic) NDR resistance since the negative resistor does not react at all in the first moment. Thus the operating point finally settles on the intersection point between the two IV curves that is apart from the NDR IV curve. To compensate the input intervention, the negative resistor begins changing its instant resistance in the according direction (S-shaped NDR - decreases, N-shaped NDR - increases) so that to send back the operating point on the negative resistance part. For this purpose, it rotates its chordal IV curve in the according direction (S-shaped NDR - counterclockwise, N-shaped NDR - clockwise) so that the operating point slides along the source IV curve and finally reaches the equilibrium on the negative resistance part. The negative resistor operating in a linear mode, can be thought as an element with a positive feedback with a loop gain < 1.
Bi-stable mode. Now let's see what the negative resistor does when operating in a bistable mode (RG < RNE for an S-shaped NDR and RG > RNE for an N-shaped NDR). Look at fig. 14 as an N-shaped example to see. The negative resistor does just the same - trying to find the desired equilibrium point, it changes more and more its instant resistance but... in the wrong direction! It is misled:) and recedes further and further from the desired equilibrium point in an avalanche-like manner. Thus the negative resistor operating in a bistable mode, can be thought as an element with a positive feedback with a loop gain > 1.
Fig. 14. A neon lamp is a typical example of an S-shaped negative differential resistor.
Tunnel diodes and Gunn diodes exhibit negative resistance region in their IV curve and have an "N" shaped transfer curve. Unijunction transistors also have negative resistance properties when a circuit is built using other components. Other negative resistance diodes have been built that have an "S" shaped transfer curve; neon lamps (fig. 14) also have S-shaped IV curves. There are transistor circuits with positive feedback (a set of interconnected bipolar transistors, one PNP and the other NPN) exhibiting negative differential resistance.
There are many mechanical systems that exhibit ranges of negative differential resistance. A general characteristic of negative resistance systems is that by driving them "firmly" it is possible to traverse the negative resistance region continuously (linear applications), but bistable switching action occurs if the system is driven "loosely" (bi-stable applications). More frequently, these mechanical NDR devices are used when operating in a bistable mode.
The amazing property of negative resistors (both true and differential) is to compensate the equivalent "positive" resistance. They do this magic by adding the same energy into circuits (as much as it loses in the positive resistance). This technique is widely used in oscillators.
For example, imagine a circuit consisting of series connected input voltage source, load and some undesired positive resistance (e.g., line resistance). When the input voltage increases, the voltage drop across the positive resistance increases as well. To compensate it, we can break the circuit and connect an equivalent S-shaped true negative resistor. It is a varying voltage source that produces the same voltage and adds it to the input voltage. As a result, the undesired resistance (the voltage drop) is compensated.
More figuratively, you can think of an S-shaped NDR as of a "faithful" rheostat connected in series with the input voltage source. When the input voltage source tries to increase the current through the circuit, the rheostat moves its slider to decrease its resistanse and to increase the current; thus it "helps" the input source.
A parallel connected N-shaped NDR can compensate positive resistance in a similar way. Initially it shunts the positive resistance. When the input voltage increases, the NDR increases its resistance and shunts less the positive resistance. In this way, it "helps" the input source to increase the voltage drop across the positive resistance.
As above, you can think of an N-shaped NDR as of a "faithful" rheostat connected in parallel with the load. When the input current source tries to increase the voltage across the load, the rheostat moves its slider to increase its resistanse and accordingly, to increase the voltage drop; thus it "helps" the input source.
They say a negative differential resistor can act as an amplifier. If this is true, is there any difference between a negative resistor and an amplifier? If yes, what is the difference? Let's clarify the topic.
What does amplification actually mean?
Strictly speaking, there is no amplification; it is just impossible. We cannot amplify energy (power); we can only control, regulate it. Then what does an amplification mean? How do we amplify? How do we make an amplifier?
It sounds bluntly, but it is true that in (analog) electronics we use the possibly silliest idea for this purpose. In order to amplify some small input power (in electronics, usually presented by input voltage), we get many times bigger (at least, VPS = K.VINmax) power source and then, imagine, we throw out the excessive power! An example of this absurd (in energetics, they never do that): in order to "amplify" 10 times 1V input voltage by a 24V supplied amplifier, we throw out (as a heat) the power according to the rest 14V. Doing that, we actually dissipate, attenuate power. As a result, there is not amplification; there is only attenuation!
We realize this absurd idea by elements acting as electrically controlled resistors (in the past - carbon microphones, tubes; now - transistors, etc.) They change their resistance to resist the current (to dissipate power), proportionally to the magnitude of the input voltage. Thus we can assemble amplifiers by using only two components: a power supply and a regulating element.
Fig. 15: This funny picture reveals the basic idea behind a tunnel diode amplifier (for simplicity, biasing circuits are omitted and the input voltage source is floating). The operation is illustrated graphically inside the circuit diagram by superimposing the two almost parallel IV curves. When the input voltage wiggles slightly, the intersection (operating) point moves vigorously.
In the negative resistance region of their IV curve, NDR do the same - they change their resistance accordingly to the current through them or the voltage across them. So, they are electrically controlled resistors; they can act as needed "amplifying" elements. The only difference with the ordinary 3-terminal "amplifying" elements is that NDR are odd 2-terminal elements whose input and output part are the same. So, we can build an odd negative resistance amplifier by connecting in series four components (fig. 15): a constant-voltage power supply V, an input voltage source VIN, a positive resistor R and a negative differential resistor NDR (e.g., an N-shaped type implemented by a tunnel diode). Actually, the two resistors constitute a sort of dynamic voltage divider driven by a varying composed voltage source (V + VIN); its transfer ratio depends vigorously on the input voltage.
When the input voltage varies slightly, the negative differential resistor changes considerably its resistance according to the input voltage, which makes the voltage divider change noticeably its transfer ratio. As a result, the voltage drops across the positive and negative resistors vary considerably; so, some of them may be used as an output voltage. To obtain maximum gain but to stay still in the linear mode, the ratio R/RNDR has to be close to but less than unity.
This requirements is illustrated graphically in fig. 15 where the two IV curves are superimposed on the common IV coordinate. The IV curve of the negative resistor is the usual N-shaped curve that starts from the coordinate origin; in the negative resistance region, it is a straight line. The other one is a compound curve consisting of two subcurves: an IV curve of the voltage source and an IV curve of the "positive" resistor (the latter is frequently named "load line" although it is not always correct). The two main curves are almost parallel; so, when the input voltage wiggles slightly, the intersection (operating) point moves vigorously along the NDR IV curve.
In this arrangement, the differential negative resistor is not an amplifier; it is just a part of an amplifier (a 2-terminal active element). The combination of the differential negative resistor acting as an active element and the power supply constitutes a true amplifier.
The same effect can be achieved by varying the positive resistance instead the voltage. In this case, the dynamic voltage divider is assembled by two varying resistors - positive and negative differential. When the positive resistor changes slightly its resistance, the negative resistor changes vigorously its resistance as a respond to the "intervention". If we take the voltage drop across the negative resistor as an output, we will obtain a sensitive resistance-to-voltage converter.
Schmitt trigger. A negative differential resistor operating in a bi-stable mode actually acts as a kind of an exotic 2-terminal Schmitt trigger. It can be used in various switching applications, e.g. to make various relaxation oscillators (with neon lamps and other NDR).
Latch (flip-flop). A negative differential resistor operating in a bi-stable mode exhibits a hysteresis. If it is properly biased so that the quiescent point to be in the middle of the hysteresis cycle, it can act as a latch (flip-flop). So it can be used to memorize one bit of data. An example: a neon lamp acting as a flip-flop with light indication.
An NDR operating in a bi-stable mode is a common design element in mechanical systems that are designed to have "detents" or a "positive action" or a "click." A popular example is the well-known pen clicker. Good examples are also the keys on a computer keyboard and on a computer mouse, taking the key position and upward force to be analogous to voltage and current, respectively. As a key is pressed downward, it initially presents a firm and increasing upward force. Beyond a critical point, a zone is entered in which the upward force decreases, which feels like a "sudden" yielding. This is often referred to as a "collapse action" mechanism. There are several keyboard technology that give such collapse action, such as buckling spring switches.
Like electrical examples above, all these NDR devices operating in a bi-stable mode can act as mechanical Schmitt triggers (clicking push-buttons) or mechanical flip-flops (toggle switches).
Both they are positive resistors that absorb energy from circuits.
Ohmic resistors have constant (steady) resistance while negative differential resistors have varying (dynamic) instant resistance.
There is only one kind of ohmic resistors but there are two kinds of negative differential resistors (S- and N-shaped).
Both they have IV curves beginning from the coordinate origin.
Negative differential resistors can be elements or electronic circuits while true negative resistors are only circuits.
Both the negative resistors are dynamic electronic elements (circuits).
Negative differential resistors are dynamic resistors while true negative resistors are dynamic electrical sources.
NDR IV curve can occupy the first or third quadrant of the coordinate system.
True negative resistors inject their own energy while differential negative resistors control external energy.
Negative differential resistors cannot be used independently; they may be used in combination with electrical sources to build true negative resistors.
True negative resistors created as negative impedance converters (NICs) consist of a constant ohmic resistor and a varying voltage source while these created on the base of NDR consist of a dynamic resistor and a constant voltage source.
When connected in series, an S-shaped NDR compensates the undesired voltage drop across the equivalent positive resistance by decreasing the undesired voltage drop across itself while the true negative resistor does the same by adding an equivalent voltage.
When connected in parallel, an N-shaped NDR compensates the undesired current consumed by the equivalent positive resistance by decreasing the (initially) consumed current while the true negative resistor does the same by adding an equivalent current.
Both they have negative resistance region represented by a part of straight line in their IV curves that is inclined to the left.
Both they have IV curves biginning from the coordinate origin.
S-shaped NDR create negative resistance by decreasing their instant resistance when the input voltage increases; N-shaped NDR create negative resistance by increasing their instant resistance when the input current increases.
When connected in series, the S-shaped NDR "helps" the input voltage source to pass the desired current through the load by decreasing the undesired voltage drop across itself while the N-shaped NDR "opposes" it by increasing the voltage drop.
When connected in parallel, the S-shaped NDR "opposes" the input current source to pass the desired current through the load by diverting a larger part of the current while the N-shaped NDR "helps" it by diverting a smaller part of the current.
Negative resistance is based on an old Wikipedia article dedicated to the phenomenon.
↑ How do we make decreased, zero and negative differential resistance?
Why tunnel diode has negative resistance?
This page was last edited on 17 July 2018, at 02:49.


A digital image transmission system for transmitting digital image data is provided to supply higher voltage between first and second external power voltages to a transmitter and a receiver respectively by connecting power output terminals of first and second power supply parts, thereby precluding data collision between the transmitter and the receiver. A digital image transmission system for transmitting digital image data(SR,SG,SB,CLK) has a host device, a transmitting and receiving reinforcing device, and a display device. The transmitting and receiving reinforcing device includes a transmitter(31), a receiver(32), and a power supply circuit(Psc1). The power supply circuit includes first and second power supply parts(312,322), and power output terminals(Vcc1,Vcc2) of the first and second power supply parts connected to each other. External power voltages which are inputted to the first and second power supply parts are outputted through the power output terminals. When the external power voltages are lower than set voltage, internal power voltage of a communication line is outputted through the power output terminals. The transmitter is combined with the host device. The receiver is combined with the display device. The communication line is connected between the transmitter and the receiver.
도 1은 기본적인 HDMI(High Definition Multimedia Interface) 형식의 디지털 영상 전송 시스템을 보여주는 도면이다. Figure 1 shows the basic HDMI (High Definition Multimedia Interface) format, a digital video transmission system.
도 2는 기본적인 DVI(Digital Visual Interface) 형식의 디지털 영상 전송 시스템을 보여주는 도면이다. Figure 2 shows the basic DVI (Digital Visual Interface) format, a digital video transmission system.
도 3은 본 발명의 제1 실시예에 따라 도 1 또는 도 2의 호스트 장치와 디스플레이 장치 사이에 개재되는 송수신 보강 장치로서의 광 케이블 모듈을 보여주는 도면이다. 3 illustrates an optical cable module as a transmission and reception reinforcement device interposed between a host device and a display device shown in Fig. 1 or 2 according to the first embodiment of the present invention.
도 4는 도 3의 송수신 보강 장치에 포함된 전원 공급 회로를 상세히 보여주는 도면이다. 4 is a diagram showing a power supply circuit included in the transmission and reception reinforcement device of Figure 3 in detail.
도 5는 본 발명의 제2 실시예에 따라 도 1 또는 도 2의 호스트 장치와 디스플레이 장치 사이에 개재되는 송수신 보강 장치로서의 광 케이블 모듈을 보여주는 도면이다. 5 illustrates an optical cable module as a transmission and reception reinforcement device interposed between a host device and a display device shown in Fig. 1 or 2 according to the second embodiment of the present invention.
도 6은 본 발명의 제3 실시예에 따라 도 1 또는 도 2의 호스트 장치와 디스플레이 장치 사이에 개재되는 송수신 보강 장치로서의 리피터를 보여주는 도면이다. 6 is a diagram showing a repeater as a transmission and reception reinforcement device interposed between the third embodiment is also in accordance with Example 1 or 2 in a host device and a display device of the present invention.
322,522,622...제2 전원 공급부. 322 522 622 ... second power supply.
본 발명은, 디지털 영상 데이터를 전송하는 디지털 영상 전송 시스템에 관한 것으로서, 보다 상세하게는, HDMI(High Definition Multimedia Interface) 또는 DVI(Digital Visual Interface) 형식의 디지털 영상 전송 시스템에 관한 것이다. The present invention relates to a digital video transmission system for transmitting digital image data, and more particularly, to a HDMI (High Definition Multimedia Interface) or a DVI (Digital Visual Interface) format, a digital video transmission system.
도 1을 참조하면, 기본적인 HDMI 형식의 디지털 영상 전송 시스템은 호스트 장치(11), 디스플레이 장치(12), 및 전기 케이블을 포함한다. Referring to Figure 1, the basic digital image transmission system of the HDMI format includes a host device 11, display device 12, and the electric cable. 여기에서, 전기 케이블은 호스트 장치(11)의 입출력 단자들(T H1 내지 T H14 )과 디스플레이 장치(12)의 입출력 단자들(T D1 내지 T D14 ) 사이에 연결된다. Here, the electrical cable is connected between the input and output terminals of the host device (11) (T H1 to H14 T) and the output terminal of the display device (12) (T D1 to T D14).
호스트 장치(11) 내의 HDMI 송신부(111)는 오디오 데이터(S AUD ), 클럭 신호(S CS ), 및 디지털 영상 데이터(S VID )를 HDMI 형식에 따라 TMDS(Transition Minimized Differential Signaling) 신호들로 변환하여 디스플레이 장치(12)에 출력한다. HDMI transmission unit 111 in the host device 11 converts the audio data (S AUD), a clock signal (S CS), and the digital image data (S VID) to the TMDS (Transition Minimized Differential Signaling) signal in accordance with the HDMI format and outputs it to the display device 12.
보다 상세하게는, 오디오 데이터(S AUD )와 디지털 영상 데이터(S VID )는, HDMI 송신부(111)에서 처리되어, 2 채널들의 적색 신호들(S R + ,S R - ), 2 채널들의 녹색 신호들(S G + ,S G - ), 그리고 2 채널들의 청색 신호들(S R + ,S R - )로써 출력된다. More specifically, the audio data (S AUD) and digital image data (S VID) has been processed by the HDMI transmission unit 111, the red signal of the second channel (S R +, S R -), the green of the second channel the signal (s + G, s G -) - is outputted as, and the blue signal of the second channel (R + s, s R). 클럭 신호(S CS )는, HDMI 송신부(111)에서 처리되어, 2 채널들의 클럭 신호들(CLK+,CLK-)로써 출력된다. The clock signal (CS S) is processed by the HDMI transmission unit 111, and is output as the clock signal of the second channel (CLK +, CLK-).
상기와 같은 I 2 C 통신에 있어서, 그래픽 제어부(112)는 클럭 신호(SCL)를 직렬 EEPROM(122)에 전송하면서 직렬 EEPROM(122)과 함께 데이터 신호(SDA)를 주고 받는다. In the I 2 C communication, such as the graphic control unit 112 send and receive a clock signal, a data signal (SDA) with a serial EEPROM (122) and transmits the (SCL) to the serial EEPROM (122). 그래픽 제어부(112)는 직렬 EEPROM(122)의 동작을 위하여 직렬 EEPROM(122)에 전원 전위(+5V)와 접지 전위(GND)를 제공한다. Graphics controller 112 provides a power supply potential (+ 5V) and the ground potential (GND) to the serial EEPROM (122) to the operation of the serial EEPROM (122). 디스플레이 장치(12)는 HPD(Hot Plug Detect) 신호용 전압(HPD)을 그래픽 제어부(112)에 인가하고, 이에 따라 그래픽 제어부(112)는 디스플레이 장치(12)와 연결되었음을 감지한다. The display device 12 detects that applying an HPD (Hot Plug Detect) signal voltage (HPD) in the graphic controller 112, and thereby the graphics controller 112 in accordance with the connection to the display device 12. 사용되지 않은 예비 단자들(T H14 ,T D14 )은 NC(No Connection) 단자들이라고 불리운다. The unused pre-terminals (T H14, T D14) is referred to as NC (No Connection) terminal.
호스트 장치(11) 내의 그래픽 제어부(112)는 EDID에 따라 HDMI 송신부(111)의 동작을 제어한다. Graphics controller 112 in the host device 11 controls the operation of the HDMI transmission unit 111 according to the EDID.
디스플레이 장치(12) 내의 HDMI 수신부(121)는 호스트 장치(11)로부터의 HDMI 형식의 TMDS 신호들을 오디오 데이터(S AUD ), 클럭 신호(S CS ), 및 디지털 영상 데이터(S VID )로 복원한다. HDMI receiving unit 121 in the display device 12 restores the TMDS signals in the HDMI format from the host device 11 to the audio data (S AUD), a clock signal (S CS), and the digital image data (S VID) .
도 2는 일반적인 DVI(Digital Visual Interface) 형식의 디지털 영상 전송 시스템을 보여준다. Figure 2 shows the format of a digital video transmission system common (Digital Visual Interface) DVI. 도 2에서 도 1과 동일한 참조 부호는 동일한 기능의 대상을 가리킨다. Figure 1 and the same reference numerals in Fig. 2 indicates a destination for the same function. 도 1의 시스템에 대한 도 2의 시스템의 차이점들만을 설명하면 다음과 같다. Even if you explain only the differences between the system of FIG. 2 for the system as follows: 1. 도 2를 참조하면, 기본적인 DVI 형식의 디지털 영상 전송 시스템은 호스트 장치(21), 디스플레이 장치(22), 및 전기 케이블을 포함한다. 2, a digital video transmission system for basic DVI format includes a host device 21, display device 22, and the electric cable. 여기에서, 전기 케이블은 호스트 장치(21)의 입출력 단자들(T H1 내지 T H14 )과 디스플레이 장치(22)의 입출력 단자들(T D1 내지 T D14 ) 사이에 연결된다. Here, the electrical cable is connected between the input and output terminals of the host device (21) (T H1 to H14 T) and the output terminal of the display device (22) (T D1 to T D14).
호스트 장치(21)는 TMDS 송신부(211) 및 그래픽 제어부(212)를 포함한다. The host device (21) comprises a TMDS transmission unit 211 and graphics controller 212. 디스플레이 장치(22)는 직렬 EEPROM(222) 및 TMDS 수신부(221)를 포함한다. Display device 22 includes a serial EEPROM (222) and the TMDS receiver 221.
호스트 장치(11) 내의 TMDS 송신부(211)는 클럭 신호(S CS ) 및 디지털 영상 데이터(S VID )를 DVI 형식에 따라 TMDS(Transition Minimized Differential Signaling) 신호들로 변환하여 디스플레이 장치(22)에 출력한다. Outputs the TMDS transmission unit 211 is a clock signal (S CS) and digital image data (S VID), the display device 22 is converted into the TMDS (Transition Minimized Differential Signaling) signal according to the DVI format, in the host device 11 do.
디스플레이 장치(22) 내의 직렬 EEPROM(222)은, 디스플레이 장치(22)의 EDID(Extended Display Identification Data)를 저장하고, I 2 C(Inter-Integrated Circuit) 통신 프로토콜에 따라 호스트 장치(21) 내의 그래픽 제어부(212)에 EDID를 제공한다. A serial EEPROM (222) in the display device 22, and stores the EDID (Extended Display Identification Data) of the display device 22 and, I 2 C (Inter-Integrated Circuit) graphics in the host device 21 according to the communication protocol, It provides the EDID to the controller 212.
호스트 장치(21) 내의 그래픽 제어부(212)는 EDID에 따라 TMDS 송신부(211)의 동작을 제어한다. Graphics controller 212 in the host device 21 controls the operation of the TMDS transmission unit 211 according to the EDID.
디스플레이 장치(22) 내의 TMDS 수신부(221)는 호스트 장치(21)로부터의 DVI 형식의 TMDS 신호들을 클럭 신호(S CS ) 및 디지털 영상 데이터(S VID )로 복원한다. TMDS receiver 221 in the display device 22 restores the TMDS signal from the DVI format from the host device 21 to the clock signal (S CS), and digital video data (VID S).
상기 도 1 또는 도 2와 같은 디지털 영상 전송 시스템에 있어서, 호스트 장치(21)와 디스플레이 장치(22) 사이의 최장 거리는 10 미터(m) 정도로 제한된다. A digital video transmission system as shown in FIG. 1 or 2, is the longest distance between the host device 21 and the display device (22) limited to about 10 meters (m). 호스트 장치(21)와 디스플레이 장치(22) 사이가 장거리인 경우, 광 케이블 모듈 또는 리피터(repeater)와 같은 송수신 보강 장치가 필요하다. If between the host device 21 and the display device 22, the long distance, the transmission and reception reinforcement device, such as an optical cable module or a repeater (repeater) is required.
이와 같은 송수신 보강 장치에는 송신부 및 수신부가 구비된다. Such transmission and reception reinforcement device is provided with a transmitter and receiver. 송신부는 상기 호스트 장치와 결합되고, 수신부는 상기 디스플레이 장치와 결합되며, 통신 선로가 송신부와 수신부 사이에 연결된다. Transmitter means associated with the host device, the receiving unit is coupled to the display device, a communication line is connected between the transmitting apparatus and the receiving apparatus. 여기에서, 송신부와 수신부에는 각각 외부 전원에 의하여 동작한다. Here, the transmitter and receiver is respectively operated by the external power source.
따라서, 상기와 같은 디지털 영상 전송 시스템의 송수신 보강 장치에 의하면, 송신부에 공급되는 제1 외부-전원 전압 및 수신부에 공급되는 제2 외부-전원 전압 사이에 차이가 존재함으로 인하여, 송신부의 동작과 수신부의 동작이 서로 균형을 이루지 못하는 경우가 있다. Therefore, according to the transmission and reception reinforcement device of the digital video transmitting system, as described above, wherein the first outer supplied to the transmitter - the second outer supplied to the power supply voltage and the receiver - due by the difference between the power supply voltage is present, operation and reception of the transmission this operation is sometimes failing to balance each other. 이 경우, 송신부와 수신부 사이에서 데이터 충돌이 발생될 수 있다. In this case, a data collision may occur between transmitter and receiver.
또한, 송수신 보강 장치의 외부 전원들이 약화되는 경우에 디지털 영상 데이터의 전송이 원활하지 못하고, 상기 외부 전원들이 차단되는 경우에 디지털 영상 데이터의 전송이 수행되지 못하는 문제점이 있다. In addition, this method can not facilitate the transfer of the digital image data when the external power source of the transmission and reception reinforcement device are weakened, there is a transfer problem can not be performed in the digital video data in the case where the external power source are blocked.
본 발명의 목적은, 호스트 장치가 송수신 보강 장치를 통하여 디스플레이 장치에 디지털 영상 데이터를 전송하는 디지털 영상 전송 시스템에 있어서, 송수신 보강 장치의 송신부와 수신부 사이에서 일어날 수 있는 데이터 충돌을 방지하고, 송수신 보강 장치의 외부 전원이 약화되거나 차단됨에도 불구하고 디지털 영상 데이터의 전송이 원활하게 유지될 수 있는 디지털 영상 전송 시스템을 제공하는 것이다. An object of the present invention, the host device is in a digital video transmission system for transmitting digital image data to the display device via the transmission and reception reinforcement device, avoid data collisions that may occur between transmitter and receiver of the transmission and reception reinforcement device, and transmitting and receiving the reinforcing Although it weakened external power to the device or block, and to provide a digital image transmission system which can be kept smooth transmission of digital image data.
상기 목적을 이루기 위한 본 발명의 디지털 영상 전송 시스템은 호스트 장치, 송수신 보강 장치, 및 디스플레이 장치를 구비한다. Digital video transmission system of the present invention for achieving the above object is provided with a host device, the transmission and reception reinforcement device, and a display device. 상기 호스트 장치는 상기 송수신 보강 장치를 통하여 상기 디스플레이 장치에 디지털 영상 데이터를 전송한 다. The host device is not to transmit the digital image data to the display device through the transmission and reception reinforcement device.
상기 송수신 보강 장치는 송신부, 수신부, 및 전원 공급 회로를 포함한다. The transmit and receive the reinforcing device comprises a transmitter, a receiver, and a power supply circuit.
상기 전원 공급 회로는 상기 송신부로의 제1 전원 공급부 및 상기 수신부로의 제2 전원 공급부를 포함한다. The power supply circuit includes a first power supply and the second power supply to the receiving unit to the transmitting unit. 상기 제1 및 제2 전원 공급부들의 전원 출력 단자들은 서로 연결된다. It said first and second power output terminals of the power supplies are interconnected. 상기 제1 및 제2 전원 공급부들 각각에 입력된 외부-전원 전압들은 상기 전원 출력 단자들을 통하여 출력된다. The first and the second external input to the power supplies respectively supply voltages are output through the power output terminal.
상기 제1 및 제2 전원 공급부들에 입력된 외부-전원 전압들 모두가 설정 전압보다 낮아지면, 상기 제1 및 제2 전원 공급부들 중의 어느 하나에서, 상기 호스트 장치와 디스플레이 장치 사이의 통신 선로로부터의 내부-전원 전압이 상기 전원 출력 단자들을 통하여 출력된다. Said first and second power supplies the external input to the - in any one of the surface is both a power supply voltage lower than the set voltage, the first and second power supplies, the communication line between the host device and the display device within-the power voltage is output through the power output terminal.
본 발명의 상기 디지털 영상 전송 시스템에 의하면, 상기 송수신 보강 장치의 상기 제1 및 제2 전원 공급부들의 전원 출력 단자들은 서로 연결된다. According to the digital image transmission system of the present invention, the first and second power output terminals of the power supplies for the transmission and reception reinforcement device are connected to each other. 이에 따라 상기 송신부에 공급되는 제1 외부-전원 전압 및 상기 수신부에 공급되는 제2 외부-전원 전압 사이에 차이가 존재하더라도, 그중에서 높은 전압이 상기 송신부와 수신부에 각각 공급되므로, 상기 송신부의 동작과 상기 수신부의 동작이 서로 균형을 이룰 수 있다. Second outer supplied to the power supply voltage and the receiver - - Accordingly, the first outside is supplied to the transmitter even when the difference between the power supply voltage is present, since the high voltage at which each supplied to the transmitting apparatus and the receiving apparatus, the operation of the transmitter and an operation of the receiver can be balanced with each other. 따라서, 상기 송신부와 상기 수신부 사이에서의 데이터 충돌이 방지될 수 있다. Thus, the data collision between the transmitter and the receiver can be prevented.
한편, 상기 제1 및 제2 전원 공급부들에 입력된 외부-전원 전압들 모두가 설정 전압보다 낮아지면, 상기 내부-전원 전압에 의하여 상기 송수신 보강 장치의 송신부와 수신부가 동작한다. On the other hand, the first and second external input to the power feeding parts - When the power supply voltage are all lower than the set voltage, the internal-by power supply voltage and operates the transmitter and receiver of the transmission and reception reinforcement device. 이에 따라, 상기 송수신 보강 장치의 외부 전원들이 약화되거나 차단됨에도 불구하고 디지털 영상 데이터의 전송이 원활하게 유지될 수 있다. Thus although a result, an external power source are weakened or cut off of the transmission and reception reinforcement device, and can be kept smooth transmission of digital image data.
이하, 본 발명의 일 실시예가 상세히 설명된다. Hereinafter be described in detail an embodiment of the present invention.
도 3은 본 발명의 제1 실시예에 따라 도 1 또는 도 2의 호스트 장치와 디스플레이 장치 사이에 개재되는 송수신 보강 장치로서의 광 케이블 모듈을 보여준다. Figure 3 illustrates an optical cable module as a transmission and reception reinforcement device interposed between a host device and a display device shown in Fig. 1 or 2 according to the first embodiment of the present invention. 도 3에서 도 1 또는 도 2와 동일한 참조 부호는 동일한 기능의 대상을 가리킨다. The same reference numerals as FIG. 1 or 2-3 are indicative of the destination of the same. 상술한 바와 같은 도 1 또는 도 2의 기본적인 디지털 영상 전송 시스템은 본 발명의 제1 실시예에 동일하게 적용되므로 그 설명이 생략된다. The basic digital video transmission system of FIG. 1 or 2 as described above is the explanation thereof is omitted since the same applies to the first embodiment of the present invention.
도 1 내지 4를 참조하면, 본 발명의 제1 실시예의 디지털 영상 전송 시스템에 포함된 송수신 보강 장치는 광 케이블(T H15 -T D15 Referring to Figure 1 to 4, the transmission and reception reinforcement device comprising a first embodiment of a digital image transmission system of the present invention is an optical cable (T H15 -T D15 내지 T H21 -T D21 ), 송신부(31), 수신부(32), 및 전원 공급 회로(P SC1 )를 포함한 광 케이블 모듈이다. To an optical cable module including T H21 -T D21), transmitter 31, receiver 32, and a power supply circuit (P SC1). 도 3에서 참조 부호 L H1 내지 L H6 Reference numeral L in Fig. 3 H1 to H6 L 및 L D1 And L D1 은 발광 다이오드들을, 그리고 P D1 내지 P D6 Is a light emitting diode, and P D1 to P D6 및 P H1 And P H1 은 수광 다이오드들을 가리킨다. It indicates a light-receiving diode.
송신부(31)는, 호스트 장치(11 또는 21)로부터의 디지털 영상 데이터(S R + 내지 CLK-) 및 I 2 C 통신용 클럭 신호(SCL)와 데이터(SDA)를 발광 구동부(311)에 의하여 광 신호들(S R Transmission unit 31, the light by the digital image data (S R + through CLK-), and I 2 C communication clock signal (SCL) and data to emit light (SDA) driving unit 311 from the host device (11 or 21) the signal (s R 내지 SDA R )로 변환하여 광 케이블(T H15 -T D15 To R SDA) converts the light cable to (T H15 -T D15 내지 T H20 -T D20 )에 출력하며, 광 케이블(T H21 -T D21 )로부터의 I 2 C 통신용 데이터(SDA L )를 전기 신호로 변환하여 호스트 장치(11 또는 21)에 제공한다. To output to the T H20 -T D20), and provides to the optical cable (T H21 -T D21) I 2 C communication data (SDA L) for converting into electrical signals the host device (11 or 21) from the.
수신부(32)는, 광 케이블(T H15 -T D15 Receiving unit 32, the optical cable (T H15 -T D15 내지 T H20 -T D20 )로부터의 광 신호들(S R To the optical signal from the T H20 -T D20) (S R 내지 SDA R )을 수광 구동부(311)에 의하여 상기 디지털 영상 데이터(S R + 내지 CLK-) 및 상기 I 2 C 통신용 클럭 신호(SCL)와 데이터(SDA)로 변환하여 디스플레이 장치(12 또는 22)에 제공하며, 디스플레이 장치(12 또는 22)로부터의 I 2 C 통신용 데이터(SDA)를 광 신호(SDA L )로 변환하여 광 케이블(T H21 -T D21 )에 출력한다. To the SDA R) by the light reception drive unit 311, the digital image data (S R + through CLK-) and display device (12 or 22 is converted into the I 2 C communication clock signal (SCL) and data (SDA)) provides a, converts the I 2 C communication data (SDA) from the display device (12 or 22) into an optical signal (SDA L) and outputs it to the optical cable (T H21 -T D21).
전원 공급 회로(P SC1 )는 송신부(31)로의 제1 전원 공급부(312) 및 수신부(32)로의 제2 전원 공급부(322)를 포함한다. A power supply circuit (P SC1) includes a second power supply 322 to the first power supply unit 312 and the receiving unit 32 to the transmission unit 31. The 제1 및 제2 전원 공급부들(312, 322)의 전원 출력 단자들(V CC1 , V CC2 )은 서로 연결된다. First and second power supplies the power output terminal of the (312, 322) (V CC1 , V CC2) are connected to each other. 제1 및 제2 전원 공급부들(312, 322) 각각에 입력된 외부-전원 전압들(V EXT1 , V EXT2 )은 전원 출력 단자들(V CC1 , V CC2 )을 통하여 출력된다. Is output through the power supply voltage (V EXT1, EXT2 V) is the power output terminal (V CC1, V CC2), - first and second power supplies (312, 322), the external input, respectively.
제1 및 제2 전원 공급부들(312, 322)에 입력된 외부-전원 전압들(V EXT1 , V EXT2 ) 모두가 설정 전압보다 낮아지면, 제1 및 제2 전원 공급부들(312, 322) 중의 어느 하나에서, 호스트 장치(11 또는 21)와 디스플레이 장치(12 또는 22) 사이의 통신 선로로부터의 내부-전원 전압(+5V)이 전원 출력 단자들(V CC1 , V CC2 )을 통하여 출력된다. First and second power supplies (312, 322), the external input to-the power supply voltage (V EXT1, V EXT2) when all lower than the set voltage, the first and second power supplies 312 and 322 of in any one of the host device (11 or 21) and the inside of the communication line between the display device (12 or 22), - the supply voltage (+ 5V) is output through the power output terminal (V CC1, V CC2).
상기한 바와 같이, 제1 및 제2 전원 공급부들(312, 322)의 전원 출력 단자 들(V CC1 , V CC2 )은 서로 연결된다. As described above, the first and second power supplies the power output terminal (V CC1, V CC2) of 312 and 322 are connected to each other. 이에 따라 송신부(31)에 공급되는 제1 외부-전원 전압(V EXT1 ) 및 수신부(32)에 공급되는 제2 외부-전원 전압(V EXT2 ) 사이에 차이가 존재하더라도, 그중에서 높은 전압이 송신부(31)와 수신부(32)에 각각 공급되므로, 송신부(31)의 동작과 수신부(32)의 동작이 서로 균형을 이룰 수 있다. A power supply voltage (V EXT1) and the second outer supplied to the receiving unit 32 - - Accordingly, the transmitter 31, the first outer supplied to, even if there is a difference between power supply voltage (V EXT2) is present, a high voltage transmission in which because each of the supply 31 and the receiving unit 32, the operation of the operation and the receiving unit 32 of the transmission 31 can be balanced with each other. 따라서, 송신부(31)와 수신부(32) 사이에서의 데이터 충돌이 방지될 수 있다. Thus, the data collision between the transmitter 31 and the receiver 32 can be prevented.
한편, 상기한 바와 같이, 제1 및 제2 전원 공급부들(312, 322)에 입력된 외부-전원 전압들(V EXT1 , V EXT2 ) 모두가 설정 전압보다 낮아지면, 상기 내부-전원 전압(+5V)에 의하여 송수신 보강 장치의 송신부(31)와 수신부(32)가 동작한다. On the other hand, the first and second power supplies (312, 322), the external input to, as described above - when all lower than the set voltage of the power supply voltage (V EXT1, V EXT2), the inner-supply voltage (+ 5V) and the transmission section 31 and reception section 32 of the transmission and reception reinforcement device operates by. 이에 따라, 송수신 보강 장치의 외부 전원들이 약화되거나 차단됨에도 불구하고 디지털 영상 데이터의 전송이 원활하게 유지될 수 있다. Thus, although an external power supply block of the transmission and reception reinforcement device are weakened or and can be kept smooth transmission of digital image data.
도 4는 도 3의 송수신 보강 장치에 포함된 전원 공급 회로(P SC1 )를 상세히 보여준다. Figure 4 shows in detail the power supply circuit (P SC1) included in the transmission and reception reinforcement device of Fig. 도 4에서 도 3과 동일한 참조 부호는 동일한 기능의 대상을 가리킨다. The same reference numerals as Fig. 3-4 are indicative of the destination of the same. 도 4에서 참조 부호 R 1 내지 R 5 는 전압 설정용 저항기들을 가리킨다. Reference numeral 4 in Fig. R 1 to R 5 denotes a resistor for voltage setting. 도 1 내지 4를 참조하여, 전원 공급 회로(P SC1 )를 상세히 설명하면 다음과 같다. Referring to Figure 1 to 4, it will be described in the power supply circuit (P SC1) in detail as follows.
제1 전원 공급부(312)에 있어서, 제1 외부-전원 전압(V EXT1 )은 제1 다이오드(D 1 )를 통하여 제1 전원 출력 단자(V CC1 )로 출력된다. First in the power supply unit 312, a first outer-is output to the power supply voltage (V EXT1) is the first diode a first power supply output terminal (V CC1) through (D 1). 호스트 장치(11 또는 21)로부터의 내부-전원 전압(+5V)은 스위칭 트랜지스터로서의 p-채널 전계 효과 트랜지 스터(TR P ) 및 제2 다이오드(D 2 )를 통하여 제1 전원 출력 단자(V CC1 )로 출력된다. The interior of the host device (11 or 21), - the supply voltage (+ 5V) is the through the p- channel field effect transitional requester (P TR), and a second diode (D 2) as the switching transistor 1, the power output terminals (V It is outputted to the CC1).
여기에서, 제1 및 제2 전원 공급부들(312, 322)에 입력된 외부-전원 전압들(V EXT1 , V EXT2 ) 모두가 설정 전압보다 낮아지면 p-채널 전계 효과 트랜지스터(TR P )가 온(On) 상태가 된다. Here, the first and second power supplies 312 and 322 to the external input - the supply voltage (V EXT1, EXT2 V) is lower than a set voltage when both p- channel field effect transistor (TR P) is turned on (On) to the state.
제2 전원 공급부(322)에 있어서, 제2 외부-전원 전압(V EXT2 )이 제3 다이오드(D 3 )를 통하여 제2 전원 출력 단자(V CC2 )로 출력되고, 제2 외부-전원 전압(V EXT2 )이 제4 다이오드(D 4 )를 통하여 제1 전원 공급부(312)로 전송된다. In the second power supply 322, the second external-power-supply voltage (V EXT2) is output to the third diode a second power output terminal (V CC2) through (D 3), the second external-power-supply voltage ( V EXT2) is transmitted to the first power supply unit 312 via a fourth diode (D 4).
제1 및 제2 전원 공급부들(312, 322)의 전원 출력 단자들(V CC1 , V CC2 )은 서로 연결된다. First and second power supplies the power output terminal of the (312, 322) (V CC1 , V CC2) are connected to each other.
제1 전원 공급부(312)에 있어서, p-채널 전계 효과 트랜지스터(TR P )의 소오스에 호스트 장치(11 또는 21)로부터의 내부-전원 전압(+5V)이 인가된다. First in the power supply unit 312, from the interior of the source of the p- channel field effect transistor (TR P) the host device (11 or 21), - the supply voltage (+ 5V) is applied. p-채널 전계 효과 트랜지스터(TR P )의 드레인에 제2 다이오드(D 2 )의 에노드가 연결된다. The node in the second diode (D 2) is connected to the drain of the p- channel field effect transistor (TR P).
제1 외부-전원 전압(V EXT1 ) 및 제2 전원 공급부(322)로부터의 제2 외부-전원 전압(V EXT2 )은 논리-합(OR) 게이트(401)를 통하여 p-채널 전계 효과 트랜지스터(TR P )의 게이트에 연결된다. The first outer-second external from the power supply voltage (V EXT1) and a second power supply (322) power supply voltage (V EXT2) is the logical-sum (OR) p- channel field effect transistor through a gate 401 ( is connected to the gate of the P TR). 이에 따라, 제1 및 제2 전원 공급부들(312, 322)에 입력된 외부-전원 전압들(V EXT1 , V EXT2 ) 모두가 설정 전압보다 낮아지면, 내부-전원 전 압(+5V)은 p-채널 전계 효과 트랜지스터(TR P ) 및 제2 다이오드(D 2 )를 통하여 제1 전원 출력 단자(V CC1 )로 출력된다. Accordingly, the first and second power supplies (312, 322), the external input to-the power supply voltage (V EXT1, V EXT2) when all lower than the set voltage, the inter-power supply voltage (+ 5V) is p - channel is output to a field effect transistor (TR P) and the second diode a first power supply output terminal (V CC1) through (D 2).
도 5는 본 발명의 제2 실시예에 따라 도 1 또는 도 2의 호스트 장치(11 또는 21)와 디스플레이 장치(12 또는 22) 사이에 개재되는 송수신 보강 장치로서의 광 케이블 모듈을 보여준다. Figure 5 illustrates an optical cable module as a transmission and reception reinforcement device interposed between the Fig. 1 or 2 according to the second embodiment of the present invention the host device (11 or 21) and the display device (12 or 22). 도 5에서 도 3과 동일한 참조 부호는 동일한 기능의 대상을 가리킨다. The same reference numerals as Fig. 3-5 are indicative of the destination of the same. 도 5에서 전원 공급 회로(P SC2 )의 구성 및 동작은 도 3 및 4를 참조하여 설명된 바와 같다. The structure of the power supply circuit (P SC2) in the fifth and operation are as described with reference to FIGS. 도 5의 제1 전원 공급부(512)의 내부 구성은 도 4의 제2 전원 공급부(312)의 것과 같다. Internal configuration of the first power supply 512 of Figure 5 is the same as that of the second power supply unit 312 of FIG. 도 5의 제2 전원 공급부(522)의 내부 구성은 도 4의 제2 전원 공급부(322)의 것과 같다. Internal configuration of the second power supply 522 of Figure 5 is the same as that of the second power supply unit 322 of FIG. 따라서, 도 3의 제1 실시예에 대한 도 5의 제2 실시예의 차이점만을 설명하면 다음과 같다. Thus, the example describes only differences between the second embodiment of Fig. 5 for the first embodiment of Fig. 3 as follows.
본 발명의 제2 실시예의 디지털 영상 전송 시스템 내의 송수신 보강 장치는 광 케이블(T H15 -T D15 내지 T H18 -T D18 ), 송신부(51), 및 수신부(52)를 포함한 광 케이블 모듈이다. Receiving the reinforcing apparatus in a second embodiment of a digital image transmission system of the present invention is an optical cable module including optical cables (T H15 T H18 -T -T D15 to D18), the transmitter 51, and receiver 52.
송신부(51)는, 호스트 장치(11 또는 21)로부터의 8 채널들의 디지털 영상 데이터(S R+ 내지 CLK-)를 발광 구동부(511)에 의하여 4 채널들의 광 신호들(S R 내지 CLK)로 변환하여 광 케이블(T H15 -T D15 내지 T H18 -T D18 )에 출력하며, 호스트 장치(11 또는 21)로부터의 I 2 C 통신용 클럭 신호(SCL)와 데이터(SDA)를 I 2 C 버퍼(513)에 의하 여 버퍼링하여 전기 케이블(T H19 -T D19 및 T H20 -T D20 )에 출력하고, 전기 케이블(T H20 -T D20 )로부터의 I 2 C 통신용 데이터(SDA)를 버퍼링하여 호스트 장치(11 또는 21)에 제공한다. Converted to a transmission unit 51, the optical signals of the four channels (S R to CLK) by a digital image data (S R + through CLK-) of 8 channels from the host device (11 or 21), the light-emitting driving part 511 the fiber optic cable and to output (T -T D15 H15 to H18 -T T D18), the host device (11 or 21) of the I 2 C communication clock signal (SCL) and data (SDA) I 2 C buffer (513 from ) W buffered by electrical cable (T H19 T H20 -T D19 and D20 -T) to the output, and buffers the I 2 C communication data (SDA) from the electric cable (T H20 -T D20), the host device thing by ( It provides a 11 or 21).
수신부(52)는, 광 케이블(T H15 -T D15 내지 T H18 -T D18 )로부터의 4 채널들의 광 신호들(S R 내지 CLK)을 수광 증폭부(621)에 의하여 8 채널들의 디지털 영상 데이터(S R + 내지 CLK-)로 변환하여 디스플레이 장치(12 또는 22)에 제공하며, 전기 케이블(T H20 -T D20 )로부터의 I 2 C 통신용 클럭 신호(SCL)와 데이터(SDA)를 I 2 C 버퍼(623)에 의하여 버퍼링하여 디스플레이 장치(12 또는 22)에 제공하며, 디스플레이 장치(12 또는 22)로부터의 I 2 C 통신용 데이터(SDA)를 I 2 C 버퍼(623)에 의하여 버퍼링하여 전기 케이블(T H20 -T D20 )에 출력한다. Receiving unit 52, the optical cable of the optical signals of 4 channels from (T -T D15 H15 to H18 T -T D18) (S R to CLK), the digital image data of the 8-channel amplified by the light receiving unit 621 and (S R + through CLK-) it provided to the display device (12 or 22) is converted into electrical cable (T H20 -T D20) I 2 C communication, a clock signal (SCL) and data (SDA) I 2 from display apparatus by buffering by the C buffer 623 (12 or 22) provides a display device (12 or 22), electrical to the I 2 C communication data (SDA) from the I buffer by 2 C buffer 623 and outputs to the cable (T H20 -T D20).
도 6은 본 발명의 제3 실시예에 따라 도 1 또는 도 2의 호스트 장치(11 또는 21)와 디스플레이 장치(12 또는 22) 사이에 개재되는 송수신 보강 장치로서의 리피터(repeater)를 보여준다. Figure 6 shows the repeater (repeater) as the transmission and reception reinforcement device interposed between a road according to a third embodiment of the present invention 1 or 2, the host device (11 or 21) and the display device (12 or 22). 도 6에서 도 3과 동일한 참조 부호는 동일한 기능의 대상을 가리킨다. The same reference numerals as Fig. 3-6 are indicative of the destination of the same. 도 6에서 전원 공급 회로(P SC3 )의 구성 및 동작은 도 3 및 4를 참조하여 설명된 바와 같다. In Figure 6, the structure and operation of the power supply circuit (P SC3) is are as described with reference to FIGS. 도 6의 제1 전원 공급부(612)의 내부 구성은 도 4의 제2 전원 공급부(312)의 것과 같다. Internal configuration of the first power supply 612 of Figure 6 is the same as that of the second power supply unit 312 of FIG. 도 6의 제2 전원 공급부(622)의 내부 구성은 도 4의 제2 전원 공급부(322)의 것과 같다. Internal configuration of the second power supply 622 of Figure 6 is the same as that of the second power supply unit 322 of FIG. 따라서, 도 3의 제1 실시예에 대한 도 6의 제3 실시예의 차이점만을 설명하면 다음과 같다. Thus, the example describes only differences between the third embodiment in Fig. 6 for the first embodiment of Fig. 3 as follows.
본 발명의 제3 실시예의 디지털 영상 전송 시스템 내의 송수신 보강 장치로서의 리피터(repeater)는 송신부(61) 및 수신부(62)를 포함한다. Repeater (repeater) as the transmission and reception reinforcement device in the third embodiment a digital image transmission system of the present invention includes a transmitter 61 and a receiver 62.
송신부(61)는, 호스트 장치(11 또는 21)로부터의 8 채널들의 디지털 영상 데이터(S R+ 내지 CLK-)를 TMDS 증폭부(611)에 의하여 증폭하여 전기 케이블(T H15 -T D15 내지 T H18 -T D18 )에 출력하며, 호스트 장치(11 또는 21)로부터의 I 2 C 통신용 클럭 신호(SCL)와 데이터(SDA)를 I 2 C 버퍼(613)에 의하여 버퍼링하여 전기 케이블(T H19 -T D19 및 T H20 -T D20 )에 출력하고, 전기 케이블(T H20 -T D20 )로부터의 I 2 C 통신용 데이터(SDA)를 I 2 C 버퍼(613)에 의하여 버퍼링하여 호스트 장치(11 또는 21)에 제공한다. Transmitter 61 includes a host device (11 or 21), the digital image data (S R + through CLK-) of 8-channel electrical cable amplified by the TMDS amplification section 611 from (T -T D15 H15 to H18 T -T D18) to the output, and the host device (11 or 21), I 2 C communication clock signal (SCL) and data (SDA) to the buffer by the I 2 C buffer 613 of the electrical cable from the (T H19 -T D19 and T H20 -T D20), the electrical cable (T H20 -T D20) from the I 2 C communication data (SDA) to I 2 C and buffered by the buffer 613, the host device (11 or 21 outputs) It provides a.
수신부(62)는, 전기 케이블(T H15 -T D15 내지 T H18 -T D18 )로부터의 디지털 영상 데이터(S R + 내지 CLK-)를 TMDS 제한 증폭부(621)에 의하여 제한적으로 증폭하여 디스플레이 장치(12 또는 22)에 제공하며, 전기 케이블로부터의 I 2 C 통신용 클럭 신호(SCL)와 데이터(SDA)를 I 2 C 버퍼(623)에 의하여 버퍼링하여 디스플레이 장치(12 또는 22)에 제공하며, 디스플레이 장치(12 또는 22)로부터의 I 2 C 통신용 데이 터(SDA)를 I 2 C 버퍼(623)에 의하여 버퍼링하여 전기 케이블(T H20 -T D20 )에 출력한다. Receiving unit 62, the electric cable (T H15 T H18 -T -T D15 to D18), the digital image data (S R + through CLK-) the display device to limited amplification by the TMDS limiting amplifier section 621 from the and providing (12 or 22), and provided to the I 2 C communication clock signal (SCL) and data (SDA) to I 2 C buffer to the display device (12 or 22) by buffering by unit 623 from the electric cable, and a display device (12 or 22), I 2 C communication data (SDA) from the buffer by the I 2 C buffer 623, and outputs to the electric cable (T H20 -T D20).
이상 설명된 바와 같이, 본 발명에 따른 디지털 영상 전송 시스템에 의하면, 송수신 보강 장치의 제1 및 제2 전원 공급부들의 전원 출력 단자들은 서로 연결된다. As described above, according to the digital image transmission system according to the present invention, the first and second power output terminals of the power supplies of the transmission and reception reinforcement device are connected to each other. 이에 따라 송신부에 공급되는 제1 외부-전원 전압 및 수신부에 공급되는 제2 외부-전원 전압 사이에 차이가 존재하더라도, 그중에서 높은 전압이 송신부와 수신부에 각각 공급되므로, 송신부의 동작과 수신부의 동작이 서로 균형을 이룰 수 있다. Second outer supplied to the power supply voltage and the receiver-Accordingly, the first outside is supplied to the transmitter even when the difference between the power supply voltage is present, since the high voltage is supplied to the transmitting apparatus and the receiving apparatus in which, the operation of the transmission operation and the receiving unit this can be balanced with each other. 따라서, 송신부와 수신부 사이에서의 데이터 충돌이 방지될 수 있다. Thus, the data collision between the transmitting apparatus and the receiving apparatus can be prevented.
한편, 제1 및 제2 전원 공급부들에 입력된 외부-전원 전압들 모두가 설정 전압보다 낮아지면, 내부-전원 전압에 의하여 송수신 보강 장치의 송신부와 수신부가 동작한다. On the other hand, the first and second external input to the power feeding parts - when all of the power supply voltage becomes lower than the set voltage, the internal-operates the transmitter and receiver of a transmission and reception reinforcement device by a power supply voltage. 이에 따라, 송수신 보강 장치의 외부 전원들이 약화되거나 차단됨에도 불구하고 디지털 영상 데이터의 전송이 원활하게 유지될 수 있다. Thus, although an external power supply block of the transmission and reception reinforcement device are weakened or and can be kept smooth transmission of digital image data.
본 발명은, 상기 실시예에 한정되지 않고, 청구범위에서 정의된 발명의 사상 및 범위 내에서 당업자에 의하여 변형 및 개량될 수 있다. The present invention is not limited to the embodiments, within the spirit and scope of the invention as defined in the claims can be modified and improved by those skilled in the art.
상기 제1 및 제2 전원 공급부들에 입력된 외부-전원 전압들 모두가 설정 전압보다 낮아지면, 상기 제1 및 제2 전원 공급부들 중의 어느 하나에서, 상기 호스트 장치와 디스플레이 장치 사이의 통신 선로로부터의 내부-전원 전압이 상기 전원 출력 단자들을 통하여 출력되는 디지털 영상 전송 시스템. Said first and second power supplies the external input to the - in any one of the surface is both a power supply voltage lower than the set voltage, the first and second power supplies, the communication line between the host device and the display device the inner-supply voltage is a digital video transmission system which is output through the power output terminal.
상기 송신부가 상기 호스트 장치와 결합되고, 상기 수신부가 상기 디스플레이 장치와 결합되며, 통신 선로가 상기 송신부와 수신부 사이에 연결된 디지털 영상 전송 시스템. The transmitter is coupled to the host device, wherein the receiving unit is coupled to the display device, the communication line is a digital video transmission system coupled between the transmitter and receiver.
상기 제1 및 제2 전원 공급부들에 입력된 외부-전원 전압들 모두가 설정 전압보다 낮아지면 상기 스위칭 트랜지스터가 온(On) 상태가 되는 디지털 영상 전송 시스템. It said first and second power supplies to the external input-power-supply voltage to both a digital video transmission system that is on the switching transistor (On) state becomes lower than the set voltage.
상기 제2 외부-전원 전압이 제4 다이오드를 통하여 상기 제1 전원 공급부로 전송되는 디지털 영상 전송 시스템. The second external-power-supply voltage is a digital video transmission system that is sent to the first power supply through a fourth diode.
상기 p-채널 전계 효과 트랜지스터의 드레인에 상기 제2 다이오드의 에노드가 연결된 디지털 영상 전송 시스템. A digital video transmission system is a node connected to the second diode to the drain of the p- channel field effect transistor.
상기 제1 외부-전원 전압 및 상기 제2 전원 공급부로부터의 상기 제2 외부-전원 전압이 논리-합(OR) 게이트를 통하여 상기 p-채널 전계 효과 트랜지스터의 게이트에 연결된 디지털 영상 전송 시스템. The first external-source voltage and the second the second external from the power supply-power supply voltage is a logical-sum (OR) digital video transmission system is connected to the gate of the p- channel field effect transistor through a gate.
상기 호스트 장치가 상기 EDID에 따라 상기 디스플레이 장치에 디지털 영상 데이터를 전송하는 디지털 영상 전송 시스템. Digital video transmission system in which the host device transmits digital image data to the display unit according to the EDID.
상기 송수신 보강 장치로부터의 HDMI 형식의 TMDS 신호들을 상기 오디오 데이터, 클럭 신호, 및 디지털 영상 데이터로 복원하는 HDMI 수신부를 포함한 디지털 영상 전송 시스템. Digital video transmission system including the HDMI receiving unit to recover the TMDS signal from the HDMI format from the transmission and reception reinforcement device, to the audio data, a clock signal, and the digital image data.
상기 송수신 보강 장치로부터의 DVI 형식의 TMDS 신호들을 상기 클럭 신호 및 디지털 영상 데이터로 복원하는 TMDS 수신부를 포함한 디지털 영상 전송 시스템. Digital video transmission system, including the TMDS receiving part for restoring the TMDS signal from the DVI format from the transmission and reception reinforcement device to the clock signal and the digital image data.
상기 광 케이블로부터의 광 신호들이 상기 디지털 영상 데이터 및 상기 I 2 C 통신용 클럭 신호와 데이터로 변환되어 상기 디스플레이 장치에 제공되며, 상기 디 스플레이 장치로부터의 상기 I 2 C 통신용 데이터가 광 신호로 변환되어 상기 광 케이블에 출력되는 디지털 영상 전송 시스템. Is that the optical signal from the optical cable, converted to the digital video data and the I 2 C communication clock signal and the data is provided to the display device, the I 2 C communication data received from the display device is converted into an optical signal digital video transmission system which is output to the optical cable.
상기 광 케이블로부터의 광 신호들이 상기 디지털 영상 데이터로 변환되어 상기 디스플레이 장치에 제공되고, 상기 전기 케이블로부터의 상기 I 2 C 통신용 클럭 신호와 데이터가 버퍼링되어 상기 디스플레이 장치에 제공되며, 상기 디스플레이 장치로부터의 상기 I 2 C 통신용 데이터가 버퍼링되어 상기 전기 케이블에 출력되는 디지털 영상 전송 시스템. Is that the optical signal from the optical cable, converted into the digital image data is provided to the display device, the I 2 C communication clock signal and data from the electrical cable is buffered and provided to the display device, from the display device of the I 2 C communication data is buffered digital video transmission system which is output to the electric cable.
상기 전기 케이블로부터의 디지털 영상 데이터가 증폭되어 상기 디스플레이 장치에 제공되고, 상기 전기 케이블로부터의 상기 I 2 C 통신용 클럭 신호와 데이터가 버퍼링되어 상기 디스플레이 장치에 제공되며, 상기 디스플레이 장치로부터의 상기 I 2 C 통신용 데이터가 버퍼링되어 상기 전기 케이블에 출력되는 디지털 영상 전송 시스템. Digital video data received from the electric cable is amplified and provided to the display device, the I 2 C communication clock signal and data from the electrical cable is buffered and provided to the display device, the I 2 from the display device, C communication data is buffered digital video transmission system which is output to the electric cable.