CN108848594B - LED drive circuit and multi-path LED lighting system - Google Patents
LED drive circuit and multi-path LED lighting system Download PDFInfo
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- CN108848594B CN108848594B CN201810757234.9A CN201810757234A CN108848594B CN 108848594 B CN108848594 B CN 108848594B CN 201810757234 A CN201810757234 A CN 201810757234A CN 108848594 B CN108848594 B CN 108848594B
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
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Abstract
The invention discloses an LED driving circuit and a multi-channel LED lighting system, wherein the current of an N-type mirror transistor is mirrored to a preset multiple through a mirror driving module, and the driving current is transmitted to a cathode of an LED through a load end of the mirror driving module after the driving current is obtained so as to drive the LED to emit light. Because the clamping module clamps the voltage of the load end of the mirror image driving module to the preset voltage, the voltage of the load end of the mirror image driving module is independent of the voltage of the anode power end and the voltage of the conduction voltage drop of the LED, no matter how the anode power end and the LED are changed, the voltage of the drain electrode of the N-type mirror image transistor is ensured to be the same as the voltage of the load end of the mirror image driving module through the negative feedback loop formed by the first operational amplifier, so that the working voltage conditions of the N-type mirror image transistor and the mirror image driving module are the same, and the driving current precision provided by the load end of the mirror image driving module for the cathode of the LED is high.
Description
Technical Field
The invention relates to the technical field of LED (LIGHT EMITTING Diode) driving, in particular to an LED driving circuit and a multi-path LED lighting system.
Background
The LED has the characteristics of low power consumption, long service life, no pollution, rich colors, strong controllability and the like, and is a revolution of the optical industry. With the development of LEDs, more and more LED products are coming into the market, such as lighting products and display devices for LED applications. Among them, an electronic driving circuit of the LED is an indispensable component in the LED product.
When the LED is applied to a display device, the LED is mainly arranged in a backlight structure of the display device, in the color mixing application of a red LED, a yellow LED and a blue LED, the LED driving circuit is required to transmit driving current with high enough precision to the LED, and then the red LED, the yellow LED and the blue LED can be mixed with accurate colors through accurate luminous brightness, but the precision of the generated driving current is lower due to the influence of the power supply connected with the LED and the influence of the conduction voltage drop of the LED.
Disclosure of Invention
In view of this, the present invention provides an LED driving circuit and a multi-path LED lighting system, where the LED driving circuit provides a high driving current precision for the cathode of the LED through the load end of the mirror driving module, and is not affected by the voltage drop between the anode power end connected to the anode of the LED and the LED itself.
In order to achieve the above purpose, the technical scheme provided by the invention is as follows:
An LED driving circuit comprising:
The device comprises a first current source, an N-type transmission transistor, an N-type mirror image transistor, a first operational amplifier, a mirror image driving module and a clamping module;
The output end of the first current source is connected with the drain electrode of the N-type transmission transistor and the grid electrode of the N-type mirror image transistor, the grid electrode of the N-type transmission transistor is connected with the output end of the first operational amplifier, the source electrode of the N-type transmission transistor is connected with the drain electrode of the N-type mirror image transistor and the negative phase end of the first operational amplifier, and the source electrode of the N-type mirror image transistor is connected with the grounding end;
The mirror image driving module is used for mirroring the current of the N-type mirror image transistor to a preset multiple, and then transmitting the current to the cathode of the LED through the load end of the mirror image driving module, wherein the anode of the LED is connected with the anode power end, and the load end of the mirror image driving module is connected with the in-phase end of the first operational amplifier;
And the clamping module is used for clamping the voltage of the load end of the mirror image driving module to a preset voltage, and the preset voltage is not greater than the upper limit voltage at the drain electrode of the N-type mirror image transistor.
Optionally, the clamping module includes:
The second current source, the second operational amplifier, the N-type clamping transistor and the current limiting element;
The output end of the second current source is connected with the same-phase end of the second operational amplifier and the input end of the current limiting element, the output end of the second operational amplifier is connected with the negative-phase end of the second operational amplifier and the grid electrode of the N-type clamping transistor, and the output end of the current limiting element is connected with the grounding end;
and the drain electrode of the N-type clamping transistor is connected with the cathode of the LED, and the source electrode of the N-type clamping transistor is connected with the load end of the mirror image driving module.
Optionally, the current limiting element is a diode, an N-type transistor in a diode connection mode, or a resistor.
Optionally, the first current source includes:
The current reference source and the first mirror source are used for mirroring the reference current output by the current reference source to a certain multiple and then outputting the reference current;
and the output end of the first mirror image source is connected with the drain electrode of the N-type transmission transistor.
Optionally, the second current source is a second mirror source, and the second mirror source is configured to mirror the reference current output by the current reference source to a certain multiple and output the reference current.
Optionally, the current reference source includes: a first P-type transistor and a second P-type transistor, the first mirror source comprising: a third P-transistor and a fourth P-type transistor;
the source electrode of the first P-type transistor and the source electrode of the third P-type transistor are both connected with a power supply end;
The grid electrode of the first P-type transistor is connected with the grid electrode of the third P-type transistor, and the grid electrode of the first P-type transistor is connected with the drain electrode of the second P-type transistor;
The drain electrode of the first P-type transistor is connected with the source electrode of the second P-type transistor, the drain electrode of the second P-type transistor is connected with the ground terminal, and the grid electrode of the second P-type transistor is connected with the grid electrode of the fourth P-type transistor;
And the drain electrode of the third P-type transistor is connected with the source electrode of the fourth P-type transistor, and the drain electrode of the fourth P-type transistor is connected with the drain electrode of the N-type transmission transistor.
Optionally, the second mirror source includes: a fifth P-type transistor and a sixth P-type transistor;
the source electrode of the fifth P-type transistor is connected with the power supply end, the grid electrode of the fifth P-type transistor is connected with the grid electrode of the first P-type transistor, the drain electrode of the fifth P-type transistor is connected with the source electrode of the sixth P-type transistor, the drain electrode of the sixth P-type transistor is connected with the same-phase end of the second operational amplifier and the input end of the current limiting element, and the grid electrode of the sixth P-type transistor is connected with the grid electrode of the second P-type transistor.
Optionally, the anode power supply end and the power supply end are mutually independent power supply ends;
Or the anode power supply end and the power supply end are the same power supply end.
Optionally, the mirror driving module includes:
a plurality of mirror sub-modules, each mirror sub-module comprising:
The N-type driving transistors and the connection control unit are connected, drain electrodes of the N-type driving transistors of all the mirror image sub-modules are connected to form a load end of the mirror image driving module, a source electrode of the N-type driving transistor is connected with a grounding end, and a grid electrode of the N-type driving transistor is connected with the connection control unit;
The connection control unit is used for controlling the grid electrode of the N-type driving transistor to be connected with the grid electrode of the N-type mirror image transistor or connected with the grounding end, and when the grid electrode of the N-type driving transistor is connected with the grid electrode of the N-type mirror image transistor, the N-type driving transistor is used for mirroring the current of the N-type mirror image transistor to a certain multiple.
Correspondingly, the invention provides a multi-path LED lighting system, which comprises:
The LED driving circuit comprises a plurality of paths of LEDs and driving circuits corresponding to the LEDs one by one, wherein the driving circuits are the LED driving circuits.
Compared with the prior art, the technical scheme provided by the invention has at least the following advantages:
The invention provides an LED driving circuit and a multi-path LED lighting system, comprising: the device comprises a first current source, an N-type transmission transistor, an N-type mirror image transistor, a first operational amplifier, a mirror image driving module and a clamping module; the output end of the first current source is connected with the drain electrode of the N-type transmission transistor and the grid electrode of the N-type mirror image transistor, the grid electrode of the N-type transmission transistor is connected with the output end of the first operational amplifier, the source electrode of the N-type transmission transistor is connected with the drain electrode of the N-type mirror image transistor and the negative phase end of the first operational amplifier, and the source electrode of the N-type mirror image transistor is connected with the grounding end; the mirror image driving module is used for mirroring the current of the N-type mirror image transistor to a preset multiple, and then transmitting the current to the cathode of the LED through the load end of the mirror image driving module, wherein the anode of the LED is connected with the anode power end, and the load end of the mirror image driving module is connected with the in-phase end of the first operational amplifier; and the clamping module is used for clamping the voltage of the load end of the mirror image driving module to a preset voltage, and the preset voltage is not greater than the upper limit voltage at the drain electrode of the N-type mirror image transistor.
As can be seen from the above, according to the technical scheme provided by the invention, the current of the N-type mirror transistor is mirrored to a preset multiple by the mirror driving module, and the driving current is transmitted to the cathode of the LED through the load end of the mirror driving module after the driving current is obtained, so as to drive the LED to emit light. The voltage of the load end of the mirror image driving module is clamped to a preset voltage by the clamping module, the preset voltage is not larger than the upper limit voltage of the drain electrode of the N-type mirror image transistor, so that the voltage of the load end of the mirror image driving module is irrelevant to the voltage of the anode power end and the voltage of the conducting voltage drop of the LED, the voltage of the drain electrode of the N-type mirror image transistor is identical to the voltage of the load end of the mirror image driving module through a negative feedback loop formed by the first operational amplifier no matter how the voltage of the anode power end and the conducting voltage drop of the LED change, the working voltage conditions of the N-type mirror image transistor and the mirror image driving module are identical, and further the current of the mirror image N-type mirror image transistor with more precision is guaranteed by the mirror image driving module, and the driving current precision provided by the load end of the mirror image driving module for the cathode of the LED is high.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required to be used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only embodiments of the present invention, and that other drawings can be obtained according to the provided drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic structural diagram of an LED driving circuit according to an embodiment of the present application;
fig. 2 is a schematic structural diagram of another LED driving circuit according to an embodiment of the present application;
fig. 3 is a schematic structural diagram of a multi-path LED lighting system according to an embodiment of the present application.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
As described in the background art, when the LED is applied to the display device, the LED is mainly disposed in the backlight structure of the display device, and in the color mixing application of the red LED, the yellow LED and the blue LED, the LED driving circuit is required to give a driving current with high enough precision to transmit to the LED, so that the red LED, the yellow LED and the blue LED can mix with accurate color by accurate light-emitting brightness, but the current LED driving circuit is affected by the power supply of the LED and the conduction voltage drop of the LED itself, so that the generated driving current has low precision.
Based on the above, the embodiment of the application provides an LED driving circuit and a multi-path LED lighting system, wherein the LED driving circuit provides high driving current precision for the cathode of an LED through the load end of a mirror image driving module, and is not influenced by the connection of the anode of the LED with the anode power end and the conduction voltage drop of the LED. In order to achieve the above objective, the technical solutions provided by the embodiments of the present application are described in detail below, with reference to fig. 1 to 3.
Referring to fig. 1, a schematic structural diagram of an LED driving circuit according to an embodiment of the present application is shown, where the LED driving circuit includes:
A first current source 100, an N-type pass transistor NL, an N-type mirror transistor N0, a first operational amplifier AMP1, a mirror drive module 200, and a clamp module 300;
The output end of the first current source 100 is connected to the drain electrode of the N-type transmission transistor NL and the gate electrode of the N-type mirror transistor N0, the gate electrode of the N-type transmission transistor NL is connected to the output end of the first operational amplifier AMP1, the source electrode of the N-type transmission transistor NL is connected to the drain electrode of the N-type mirror transistor N0 and the negative phase end of the first operational amplifier AMP1, and the source electrode of the N-type mirror transistor N0 is connected to the ground Gnd;
The mirror driving module 200 is configured to mirror the current of the N-type mirror transistor N0 to a preset multiple, and then transmit the current to the cathode of the LED through the load terminal B of the mirror driving module 200, where the anode of the LED is connected to the anode power terminal vdd_led, and the load terminal of the mirror driving module 200 is connected to the in-phase terminal of the first operational amplifier AMP 1;
And the clamping module 300 is configured to clamp the voltage at the load terminal B of the mirror driving module 200 to a preset voltage, where the preset voltage is not greater than an upper limit voltage at the drain of the N-type mirror transistor N0.
As can be seen from the above, according to the technical scheme provided by the embodiment of the application, the current of the N-type mirror transistor is mirrored to a preset multiple by the mirror driving module, so that the driving current is obtained and then transmitted to the cathode of the LED through the load end of the mirror driving module, so as to drive the LED to emit light. The voltage of the load end of the mirror image driving module is clamped to a preset voltage by the clamping module, the preset voltage is not larger than the upper limit voltage of the drain electrode of the N-type mirror image transistor, so that the voltage of the load end of the mirror image driving module is irrelevant to the voltage of the anode power end and the voltage of the conducting voltage drop of the LED, and therefore, no matter how the voltage of the anode power end and the voltage of the conducting voltage drop of the LED change, the voltage of the drain electrode of the N-type mirror image transistor is identical to the voltage of the load end of the mirror image driving module through a negative feedback loop formed by the first operational amplifier, so that the working voltage conditions of the N-type mirror image transistor and the mirror image driving module are identical, and the driving current precision provided by the load end of the mirror image driving module for the cathode of the LED is guaranteed to be high.
The following describes in detail the structure of a specific LED driving circuit provided by the embodiment of the present application with reference to fig. 2, and referring to fig. 2, a schematic structural diagram of another LED driving circuit provided by the embodiment of the present application is shown, where the clamping module 300 provided by the embodiment of the present application includes:
A second current source 310, a second operational amplifier AMP2, an N-type clamp transistor NC, and a current limiting element 320;
The output end of the second current source 310 is connected to the non-inverting end of the second operational amplifier AMP2 and the input end of the current limiting element 320, the output end of the second operational amplifier AMP2 is connected to the negative phase end thereof and the gate of the N-type clamp transistor NC, and the output end of the current limiting element 320 is connected to the ground Gnd;
And the drain electrode of the N-type clamping transistor NC is connected with the cathode of the LED, and the source electrode of the N-type clamping transistor NC is connected with the load end B of the mirror image driving module 200.
In the clamp module 300 provided by the embodiment of the application, the current of the second current source 310 flows through the current limiting element 320 to obtain a voltage VE, and then the output vf=ve of the buffer amplifier formed by connecting the second operational amplifier AMP2, so that the output of the second operational amplifier AMP2 has stronger driving capability to control the N-type clamp transistor NC. In an embodiment of the present application, the N-type clamp transistor NC provided in the present application has a larger size, so that it has a smaller on-resistance, and the specific parameters of the size are not specifically limited, and specific design is required according to practical applications.
The N-type clamp transistor NC is configured to clamp the voltage at the load terminal B of the mirror driving module 200, that is, when the driving current flows through the N-type clamp transistor NC, the gate-source voltage difference VGS of the N-type clamp transistor NC is a determined value (e.g., 0.9V-1.5V, including an endpoint value), that is, the voltage VB at the load terminal B of the mirror driving module 200 is lower than a certain voltage value VF, and the voltage value has a positive relationship with the driving current, and by analyzing the voltage VA variation at the drain of the N-type mirror transistor N0 to optimally design the voltage value ve=vf according to the analysis result, the voltage vb=vf-VGS at the load terminal B of the mirror driving module 200 can be designed to be a preset voltage, and the preset voltage is not greater than the upper limit voltage of the voltage VA at the drain of the N-type mirror transistor N0.
Therefore, no matter how the voltage of the on voltage drop of the anode power supply terminal vdd_led and the LED itself changes, the voltage VB of the load terminal B of the mirror driving module 200 is clamped at the preset voltage by the N-type clamping transistor NC, and the preset voltage is not greater than the upper limit voltage of the voltage VA at the drain of the N-type mirror transistor N0, the negative feedback loop connected to the first operational amplifier AMP1 can ensure that the voltage VA at the drain of the N-type mirror transistor N0 is the same as the voltage VB of the load terminal B of the mirror driving module 200, so that the working voltage conditions of the N-type mirror transistor N0 and the mirror driving module 200 are the same, and further ensure that the driving current precision provided by the load terminal B of the mirror driving module 200 for the cathode of the LED is high.
In an embodiment of the present application, the current limiting element 320 may be a diode, an N-type transistor with a diode connection, or a resistor. Preferably, the current limiting element 320 provided in the embodiment of the present application is an N-type transistor ND in a diode connection manner, where the current limiting element 320 and the N-type mirror transistor N0 and an N-type driving transistor NX described later belong to the N-type transistor, so that the current limiting element 320 and the N-type mirror transistor N0 are drawn at positions close to each other during drawing, and parameters such as on threshold values of the N-type transistors are the same and changed during the semiconductor manufacturing process, so that mismatch between the parameters is small, and the influence of process deviation occurring during the manufacturing on the LED driving circuit can be improved.
Referring to fig. 2, the first current source 100 according to the embodiment of the present application includes:
A current reference source 110 and a first mirror source 120, where the first mirror source 120 is configured to mirror a reference current Ib output by the current reference source 110 to a certain multiple and output the reference current Ib;
the output of the first mirror source 120 is connected to the drain of the N-type pass transistor NL.
And, the second current source 310 provided in the embodiment of the present application may be a second mirror source, where the second mirror source 310 is configured to mirror the reference current Ib output by the current reference source 110 to a certain multiple and then output the reference current Ib.
In the embodiment of the present application, the current sources provided by the present application may be casecode current sources, that is, the current reference source 110 provided by the embodiment of the present application includes: a first P-type transistor P1 and a second P-type transistor P2, the first mirror source comprising: a third P-transistor and a fourth P-type transistor P4;
the source electrode of the first P-type transistor P1 and the source electrode of the third P-type transistor P3 are both connected to the power supply terminal VDD;
the gate of the first P-type transistor P1 is connected to the gate of the third P-type transistor P3, and the gate of the first P-type transistor P1 is connected to the drain of the second P-type transistor P2;
The drain electrode of the first P-type transistor P1 is connected to the source electrode of the second P-type transistor P2, the drain electrode of the second P-type transistor P2 is connected to the ground Gnd, the gate electrode of the second P-type transistor P2 is connected to the gate electrode of the fourth P-type transistor P4, and the gate electrode of the second P-type transistor P2 is externally connected to the control terminal Vdp;
and the drain electrode of the third P-type transistor P3 is connected to the source electrode of the fourth P-type transistor P4, and the drain electrode of the fourth P-type transistor P4 is connected to the drain electrode of the N-type transmission transistor NL.
And, the second mirror source 310 provided in the embodiment of the present application includes: a fifth P-type transistor P5 and a sixth P-type transistor P6;
The source of the fifth P-type transistor P5 is connected to the power supply terminal VDD, the gate of the fifth P-type transistor P5 is connected to the gate of the first P-type transistor P1, the drain of the fifth P-type transistor P5 is connected to the source of the sixth P-type transistor P6, the drain of the sixth P-type transistor P6 is connected to the non-inverting terminal of the second operational amplifier AMP1 and the input terminal of the current limiting element 320, and the gate of the sixth P-type transistor P6 is connected to the gate of the second P-type transistor P2.
In an embodiment of the present application, the anode power supply terminal vdd_led and the power supply terminal VDD provided by the present application may be independent power supply terminals;
Or the anode power supply terminal vdd_led and the power supply terminal VDD provided by the present application may be the same power supply terminal.
Referring to fig. 2, the mirror driving module 200 according to the embodiment of the present application includes:
A plurality of mirror sub-modules 210, each mirror sub-module 210 comprising:
The drains of the N-type driving transistors NX of all the mirror sub-modules 210 are connected to form a load end B of the mirror driving module 200, the source of the N-type driving transistor NX is connected to the ground end Gnd, and the gate of the N-type driving transistor NX is connected to the connection control unit 211;
The connection control unit 211 is configured to control the gate of the N-type driving transistor NX to be connected to the gate of the N-type mirror transistor N0 or to be connected to the ground Gnd, and when the gate of the N-type driving transistor NX is connected to the gate of the N-type mirror transistor N0, the N-type driving transistor NX is configured to mirror the current of the N-type mirror transistor NX to a certain multiple.
It can be understood that when the gate of the N-type driving transistor NX is connected to the gate of the N-type mirror transistor N0, the N-type driving transistor NX is configured to mirror the current of the N-type mirror transistor N0 to a certain multiple, where the multiple of mirroring of all N-type driving transistors NX may be the same or different, which is not limited in particular. Since all N-type driving transistors NX are connected in parallel to the load end B of the mirror driving module 200, when the mirror driving module 200 works, the driving current output by the load end B of the mirror driving module 200 is the sum of the currents of all N-type driving transistors NX with the gates connected to the gates of the N-type mirror transistors N0, and therefore, the gates of the N-type driving transistors NX are controlled to connect to the gates of the N-type mirror transistors N0, so as to obtain the driving current from the current of the mirror N-type mirror transistor N0 to the required multiple.
In an embodiment of the present application, the connection control unit 211 provided by the present application may include an inverter INV and two transistors M1 and M2 having the same turn-on type (for example, the transistors M1 and M2 are both N-type transistors), wherein the gate of the transistor M1 is connected to the input terminal of the inverter INV, the transistor M1 is connected between the gate of the N-type driving transistor NX and the gate of the N-type mirror transistor N0, the gate of the transistor M2 is connected to the output terminal of the inverter INV, and the transistor M2 is connected between the gate of the N-type driving transistor NX and the ground terminal Gnd; when the grid electrode of the N-type driving transistor NX is required to be controlled to be connected with the grid electrode of the N-type mirror transistor N0, a control signal is connected between the grid electrode of the transistor M1 and the input end of the inverter INV, the transistor M1 is controlled to be conducted, the grid electrode of the N-type driving transistor NX is controlled to be connected with the grid electrode of the N-type mirror transistor N0, and the inverted control signal is used for controlling the transistor M2 to be cut off due to the inversion of the control signal by the inverter INV, so that the grid electrode of the N-type driving transistor NX is prevented from being communicated with the ground end Gnd; in addition, when the connection between the gate of the N-type driving transistor NX and the gate of the N-type mirror transistor N0 needs to be disconnected, the gate of the transistor M1 and the input terminal of the inverter INV are connected with a control signal, the control transistor M1 is turned off, and the connection between the gate of the N-type driving transistor NX and the gate of the N-type mirror transistor N0 is disconnected, and, due to the inversion of the control signal by the inverter INV, the inverted control signal controls the transistor M2 to be turned on, and controls the gate of the N-type driving transistor NX to be connected with the ground Gnd, thereby rapidly turning off the N-type driving transistor NX.
Correspondingly, the embodiment of the application provides a multi-path LED lighting system, which comprises:
The LED driving circuit comprises a plurality of paths of LEDs and driving circuits corresponding to the LEDs one by one, wherein the driving circuits are the LED driving circuits provided by any one embodiment.
Referring to fig. 3, a schematic structural diagram of a multi-path LED lighting system according to an embodiment of the present application is shown, where the multi-path LED lighting system includes:
The driving circuit 410, the driving circuit 420 and the driving circuit 430 are all LED driving circuits provided in any of the above embodiments.
It can be appreciated that in the multi-path LED lighting system provided by the embodiment of the present application, since the respective conduction voltage drops of the red light emitting diode LR, the green light emitting diode LG and the blue light emitting diode LB are different, wherein the conduction voltage drops of the green light emitting diode LG and the blue light emitting diode LB are substantially the same, and the conduction voltage drop of the red light emitting diode LR is smaller than the conduction voltage drops of the green light emitting diode LG and the blue light emitting diode LB, when anodes of the red light emitting diode LR, the green light emitting diode LG and the blue light emitting diode LB are all connected to the same anode power supply terminal vdd_led, if no clamping module is provided in the driving circuit, the red light emitting diode LR, the green light emitting diode LG and the blue light emitting diode LB affect the voltages of the load terminals of the mirror driving modules in the respective corresponding driving circuits; the driving circuit 410, the driving circuit 420 and the driving circuit 430 provided in the embodiment of the application are all disposed in the clamping module, so that no matter how the conduction voltage drops of the red light emitting diode LR, the green light emitting diode LG and the blue light emitting diode LB change, the voltage at the load end of the mirror image driving module is clamped at the preset voltage, and the voltage at the drain electrode of the N-type mirror image transistor is ensured to be the same as the voltage at the load end of the mirror image driving module through the negative feedback loop formed by the first operational amplifier, so that the working voltage conditions of the N-type mirror image transistor and the mirror image driving module are the same, and the current of the mirror image N-type mirror image transistor which is more accurate by the mirror image driving module is ensured, so that the driving current precision provided by the load end of the mirror image driving module for the cathode of the LED is high, and finally the light mixing effect of the multi-path LED lighting system is ensured to be high.
In an embodiment of the present application, the multi-path LED lighting system provided by the present application may be applied to a display device, a lighting device, or other lighting structures, which is not particularly limited.
The embodiment of the application provides an LED driving circuit and a multi-path LED lighting system, comprising: the device comprises a first current source, an N-type transmission transistor, an N-type mirror image transistor, a first operational amplifier, a mirror image driving module and a clamping module; the output end of the first current source is connected with the drain electrode of the N-type transmission transistor and the grid electrode of the N-type mirror image transistor, the grid electrode of the N-type transmission transistor is connected with the output end of the first operational amplifier, the source electrode of the N-type transmission transistor is connected with the drain electrode of the N-type mirror image transistor and the negative phase end of the first operational amplifier, and the source electrode of the N-type mirror image transistor is connected with the grounding end; the mirror image driving module is used for mirroring the current of the N-type mirror image transistor to a preset multiple, and then transmitting the current to the cathode of the LED through the load end of the mirror image driving module, wherein the anode of the LED is connected with the anode power end, and the load end of the mirror image driving module is connected with the in-phase end of the first operational amplifier; and the clamping module is used for clamping the voltage of the load end of the mirror image driving module to a preset voltage, and the preset voltage is not greater than the upper limit voltage at the drain electrode of the N-type mirror image transistor.
As can be seen from the above, according to the technical scheme provided by the embodiment of the application, the current of the N-type mirror transistor is mirrored to a preset multiple by the mirror driving module, so that the driving current is obtained and then transmitted to the cathode of the LED through the load end of the mirror driving module, so as to drive the LED to emit light. The voltage of the load end of the mirror image driving module is clamped to a preset voltage by the clamping module, the preset voltage is not larger than the upper limit voltage of the drain electrode of the N-type mirror image transistor, so that the voltage of the load end of the mirror image driving module is irrelevant to the voltage of the anode power end and the voltage of the conducting voltage drop of the LED, and therefore, no matter how the voltage of the anode power end and the voltage of the conducting voltage drop of the LED change, the voltage of the drain electrode of the N-type mirror image transistor is identical to the voltage of the load end of the mirror image driving module through a negative feedback loop formed by the first operational amplifier, so that the working voltage conditions of the N-type mirror image transistor and the mirror image driving module are identical, and the driving current precision provided by the load end of the mirror image driving module for the cathode of the LED is guaranteed to be high.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (9)
1. An LED driving circuit, comprising:
The device comprises a first current source, an N-type transmission transistor, an N-type mirror image transistor, a first operational amplifier, a mirror image driving module and a clamping module;
The output end of the first current source is connected with the drain electrode of the N-type transmission transistor and the grid electrode of the N-type mirror image transistor, the grid electrode of the N-type transmission transistor is connected with the output end of the first operational amplifier, the source electrode of the N-type transmission transistor is connected with the drain electrode of the N-type mirror image transistor and the negative phase end of the first operational amplifier, and the source electrode of the N-type mirror image transistor is connected with the grounding end;
The mirror image driving module is used for mirroring the current of the N-type mirror image transistor to a preset multiple, and then transmitting the current to the cathode of the LED through the load end of the mirror image driving module, wherein the anode of the LED is connected with the anode power end, and the load end of the mirror image driving module is connected with the in-phase end of the first operational amplifier;
The clamping module is used for clamping the voltage of the load end of the mirror image driving module to a preset voltage, and the preset voltage is not greater than the upper limit voltage at the drain electrode of the N-type mirror image transistor;
The first current source includes:
The current reference source and the first mirror source are used for mirroring the reference current output by the current reference source to a certain multiple and then outputting the reference current;
and the output end of the first mirror image source is connected with the drain electrode of the N-type transmission transistor.
2. The LED driving circuit of claim 1, wherein the clamping module comprises:
The second current source, the second operational amplifier, the N-type clamping transistor and the current limiting element;
The output end of the second current source is connected with the same-phase end of the second operational amplifier and the input end of the current limiting element, the output end of the second operational amplifier is connected with the negative-phase end of the second operational amplifier and the grid electrode of the N-type clamping transistor, and the output end of the current limiting element is connected with the grounding end;
and the drain electrode of the N-type clamping transistor is connected with the cathode of the LED, and the source electrode of the N-type clamping transistor is connected with the load end of the mirror image driving module.
3. The LED driving circuit of claim 2, wherein the current limiting element is a diode, an N-type transistor in a diode connection, or a resistor.
4. The LED driving circuit of claim 2, wherein the second current source is a second mirror source, and the second mirror source is configured to mirror the reference current output by the current reference source to a multiple and output the reference current.
5. The LED driver circuit of claim 4, wherein the current reference source comprises: a first P-type transistor and a second P-type transistor, the first mirror source comprising: a third P-type transistor and a fourth P-type transistor;
the source electrode of the first P-type transistor and the source electrode of the third P-type transistor are both connected with a power supply end;
The grid electrode of the first P-type transistor is connected with the grid electrode of the third P-type transistor, and the grid electrode of the first P-type transistor is connected with the drain electrode of the second P-type transistor;
The drain electrode of the first P-type transistor is connected with the source electrode of the second P-type transistor, the drain electrode of the second P-type transistor is connected with the ground terminal, and the grid electrode of the second P-type transistor is connected with the grid electrode of the fourth P-type transistor;
And the drain electrode of the third P-type transistor is connected with the source electrode of the fourth P-type transistor, and the drain electrode of the fourth P-type transistor is connected with the drain electrode of the N-type transmission transistor.
6. The LED driving circuit of claim 5, wherein the second mirror source comprises: a fifth P-type transistor and a sixth P-type transistor;
the source electrode of the fifth P-type transistor is connected with the power supply end, the grid electrode of the fifth P-type transistor is connected with the grid electrode of the first P-type transistor, the drain electrode of the fifth P-type transistor is connected with the source electrode of the sixth P-type transistor, the drain electrode of the sixth P-type transistor is connected with the same-phase end of the second operational amplifier and the input end of the current limiting element, and the grid electrode of the sixth P-type transistor is connected with the grid electrode of the second P-type transistor.
7. The LED driving circuit of claim 5, wherein the anode power supply terminal and the power supply terminal are independent power supply terminals;
Or the anode power supply end and the power supply end are the same power supply end.
8. The LED driving circuit of claim 1, wherein the mirror driving module comprises:
a plurality of mirror sub-modules, each mirror sub-module comprising:
The N-type driving transistors and the connection control unit are connected, drain electrodes of the N-type driving transistors of all the mirror image sub-modules are connected to form a load end of the mirror image driving module, a source electrode of the N-type driving transistor is connected with a grounding end, and a grid electrode of the N-type driving transistor is connected with the connection control unit;
The connection control unit is used for controlling the grid electrode of the N-type driving transistor to be connected with the grid electrode of the N-type mirror image transistor or connected with the grounding end, and when the grid electrode of the N-type driving transistor is connected with the grid electrode of the N-type mirror image transistor, the N-type driving transistor is used for mirroring the current of the N-type mirror image transistor to a certain multiple.
9. A multiple LED lighting system, comprising:
The LED driving circuit comprises a plurality of paths of LEDs and driving circuits corresponding to the LEDs one by one, wherein the driving circuits are the LED driving circuits according to any one of claims 1-8.
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| CN110139434B (en) * | 2019-05-23 | 2021-08-27 | 上海艾为电子技术股份有限公司 | Driving circuit and driving method |
| CN113381702B (en) * | 2021-06-16 | 2023-12-05 | 锐迪科创微电子（北京）有限公司 | Low noise amplifier, radio frequency receiver and radio frequency terminal |
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| CN101557669B (en) * | 2009-03-11 | 2012-10-03 | 深圳市民展科技开发有限公司 | High precision controllable current source |
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