CN103037597B - Multi-channel LED (Light Emitting Diode) constant current control circuit and LED light source control system - Google Patents
Multi-channel LED (Light Emitting Diode) constant current control circuit and LED light source control system Download PDFInfo
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Abstract
The invention discloses a multi-channel LED (Light Emitting Diode) constant current control circuit, which comprises a power supply module, a booster module, a DC/DC (Direct Current/Direct Current) control module, an LED string module, a constant current adjusting module and a feedback control module, wherein an input end of the booster module is connected with the power supply module; an output end of the booster module is connected with an input end of the constant current adjusting module through the LED string module; the feedback control module is connected with a feedback input end of the DC/DC control module and respectively connected with an output end and a control end of the constant current adjusting module; and a driving output end of the DC/DC control module is connected with a control end of the booster module. The invention further discloses an LED light source control system, which comprises the multi-channel LED constant current control circuit. The multi-channel LED constant current control circuit disclosed by the invention has the advantage as follows: the constant current control precision is high; through adjustment of the current of each LED string, the currents of the LED strings are equal to each other, so that the illumination brightnesses of the LED strings are equal to each other; the uniformity of the LED illumination brightnesses is enhanced; and the multi-channel LED constant current control circuit is suitable for any electronic system using constant current control.
Description
Technical field
The present invention relates to the technical field of IC design, particularly relate to a kind of multi-channel LED constant current control circuit and LED light source control system.
Background technology
LED, as a kind of green light source of low-power consumption, is widely used in illumination, backlight display field.From the C-V characteristic of LED, LED current and voltage exponentially relation, small voltage change can cause very large curent change, and electric current directly determines the luminosity of LED, so in order to make the brightness of LED keep stable, must constant current mode be adopted, instead of constant voltage mode.
In prior art, when LED number is less, usually adopt the mode of series connection, as shown in Figure 1, the electric current flowing through each LED is equal, so brightness is consistent.The advantage of this structure is that structure is simple, and shortcoming to be applicable to the less application of LED number.
When LED number is more, need to adopt series-parallel mode, so just form the topological structure of multi-string LED parallel connection, this structure is applicable to the more application of LED number.The mode of current sample has two kinds usually: first kind of way as shown in Figure 2, the only electric current of sampling a certain LED strip wherein, the current constant of sampled LED strip can be guaranteed like this, but the electric current between each LED strip is variant unavoidably, so cause the inconsistent phenomenon of brightness between each LED strip; As shown in Figure 3, the electric current of sampling is the electric current sum of all LED strip to the second way, and this structure can guarantee that the electric current sum of all LED strip keeps constant, but can not solve the current difference problem between LED strip.
Summary of the invention
Main purpose of the present invention proposes a kind of multi-channel LED constant current control circuit and LED light source control system, and be intended to the electric current by regulating every paths of LEDs string, make the electric current of every paths of LEDs string equal, the luminosity realizing every paths of LEDs string is equal.
In order to achieve the above object, the present invention proposes a kind of multi-channel LED constant current control circuit, this multi-channel LED constant current control circuit comprises supply module, the boost module for being carried out boosting by input voltage, the DC/DC control module and the LED strip module that are used for controlling described boost module boosting ratio, described LED strip module comprises at least two paths of LED string, and this multi-channel LED constant current control circuit also comprises the constant current adjusting module of the electric current for adjusting LED strip described in each road and the feedback control module for controlling described constant current adjusting module adjustment electric current; Wherein:
The input of described boost module is connected with described supply module, output is connected with the input of described LED strip module, the output of described LED strip module is connected with the input of described constant current adjusting module, the output of described constant current adjusting module is connected with the input of described feedback control module, the output of described feedback control module is connected with the feedback input end of described DC/DC control module respectively and the control end of described constant current adjusting module connects, and the drive output of described DC/DC control module is connected with the control end of described boost module.
Preferably, described boost module comprises inductance, diode, electric capacity and switching tube; One end of described inductance, as the input of described boost module, is connected with described supply module, and the other end of described inductance is connected with the anode of described diode, and is connected with the drain electrode of described switching tube; The grid of described switching tube is connected with the output of described DC/DC control module, the source ground of described switching tube; The negative electrode of described diode through described capacity earth, and is connected with the input of LED strip described in each road respectively.
Preferably, described switching tube is NMOS tube.
Preferably, described DC/DC control module comprises DC/DC accessory power supply and DC/DC control chip, the positive pole of described DC/DC accessory power supply is connected with the power end of described DC/DC control chip, and the negative pole of described DC/DC accessory power supply is connected with the earth terminal of described DC/DC control chip.
Preferably, described DC/DC control chip comprises reference power supply, error amplifier, comparator and driver element; The positive pole of described reference power supply is connected with the in-phase input end of described error amplifier, the minus earth of described reference power supply; The output of described error amplifier is connected with the inverting input of described comparator; The in-phase input end of described comparator is connected with sawtooth waveforms input, and the output of described comparator is connected with the input of described driver element; The output of described driver element, as the output of described DC/DC control module, is connected with the grid of described switching tube.
Preferably, LED strip described in each road comprises some series connection and the identical LED of conducting direction, and described in each road, the anode tap of LED strip is all connected with the negative electrode of described diode.
Preferably, described constant current adjusting module comprises at least two the constant current adjustment units corresponding with described LED strip, and the input of constant current adjustment unit described in each is connected with the cathode terminal of LED strip described in.
Preferably, constant current adjustment unit described in each comprises Correctional tube, sampling resistor, operational amplifier and two-way selector; Wherein:
The drain electrode of described Correctional tube is as the input of described constant current adjustment unit, connect with the cathode terminal of LED strip described in corresponding, the source electrode of described Correctional tube is through described sampling resistor ground connection, and be connected with the inverting input of described operational amplifier and an input pin of described feedback control module respectively, the grid of described Correctional tube is connected with the output of described operational amplifier; The in-phase input end of described operational amplifier is connected with the output of described two-way selector; The first input end of described two-way selector is connected with an output pin of described feedback control module, and be connected with the inverting input of described error amplifier, second input of described two-way selector is connected with the positive pole of described reference power supply, and the control end of described two-way selector is connected with another output pin of described feedback control module.
Preferably, described Correctional tube is NMOS tube.
The present invention also proposes a kind of LED light source control system, this LED light source control system comprises multi-channel LED constant current control circuit, this multi-channel LED constant current control circuit comprises supply module, for the boost module that input voltage is carried out boosting, for controlling DC/DC control module and the LED strip module of described boost module boosting ratio, described LED strip module comprises at least two paths of LED string, this multi-channel LED constant current control circuit also comprises the constant current adjusting module of the electric current for adjusting LED strip described in each road and the feedback control module for controlling described constant current adjusting module adjustment electric current, wherein:
The input of described boost module is connected with described supply module, output is connected with the input of described LED strip module, the output of described LED strip module is connected with the input of described constant current adjusting module, the output of described constant current adjusting module is connected with the input of described feedback control module, the output of described feedback control module is connected with the feedback input end of described DC/DC control module respectively and the control end of described constant current adjusting module connects, and the drive output of described DC/DC control module is connected with the control end of described boost module.
The multi-channel LED constant current control circuit that the present invention proposes, LED strip module is exported to after being boosted by the input voltage of power supply by boost module, the electric current flowing through each paths of LEDs string produces a sampled voltage in the constant current adjustment unit of correspondence, by the control of feedback control module, minimum sampled voltage is fed back to DC/DC control module, to control the boosting ratio of boost module, regulation output voltage; Simultaneously, adopt minimum current in each paths of LEDs string as benchmark, control signal is exported to constant current adjusting module by feedback control module, different voltage references selected by the two-way selector controlled in each constant current adjustment unit, make the electric current of remaining LED strip be all that benchmark is regulated by Correctional tube with minimum current, and then make the electric current of every paths of LEDs string equal, the luminosity realizing every paths of LEDs string is equal, improve the precision of current constant control, strengthen the uniformity of LED luminosity.
Accompanying drawing explanation
Fig. 1 is the electrical block diagram of prior art LED constant-current control circuit one embodiment;
Fig. 2 is the electrical block diagram of another embodiment of prior art LED constant-current control circuit;
Fig. 3 is the electrical block diagram of the another embodiment of prior art LED constant-current control circuit;
Fig. 4 is the theory diagram of multi-channel LED constant current control circuit preferred embodiment of the present invention;
Fig. 5 is the electrical block diagram of multi-channel LED constant current control circuit preferred embodiment of the present invention;
Fig. 6 is the internal circuit configuration schematic diagram of DC/DC control chip in multi-channel LED constant current control circuit of the present invention.
The realization of the object of the invention, functional characteristics and advantage will in conjunction with the embodiments, are described further with reference to accompanying drawing.
Detailed description of the invention
Technical scheme of the present invention is further illustrated below in conjunction with Figure of description and specific embodiment.Should be appreciated that specific embodiment described herein only in order to explain the present invention, be not intended to limit the present invention.
The present invention proposes a kind of multi-channel LED constant current control circuit.
With reference to the theory diagram that Fig. 4, Fig. 4 are multi-channel LED constant current control circuit preferred embodiment of the present invention.
In the embodiment of the present invention, multi-channel LED constant current control circuit comprises supply module 10, boost module 20, DC/DC control module 30, LED strip module 40, constant current adjusting module 50 and feedback control module 60; In the present embodiment, boost module 20 boosts for the voltage inputted by supply module 10, increase output voltage, DC/DC control module 30 is for controlling the boosting ratio of boost module 20, regulation output voltage, LED strip module 40 comprises at least two paths of LED string, to be arranged in parallel between each paths of LEDs string and conducting direction is identical, constant current adjusting module 50 is for adjusting the electric current of each paths of LEDs string, feedback control module 60 adjusts electric current for controlling constant current adjusting module 50, makes the electric current of every paths of LEDs string equal.
Wherein, the input of boost module 20 is connected with supply module 10, the output of boost module 20 is connected with the input of LED strip module 40, the output of LED strip module 40 is connected with the input of constant current adjusting module 50, the output of constant current adjusting module 50 is connected with the input of feedback control module 60, the output of feedback control module 60 is connected with the feedback input end of DC/DC control module 30 respectively and the control end of constant current adjusting module 50 connects, and the drive output of DC/DC control module 30 is connected with the control end of boost module 20.
The present embodiment exports LED strip module 40 to after being boosted by the input voltage inputted from supply module 10 by boost module 20, the electric current flowing through LED strip produces sampled voltage in constant current adjusting module 50, all sampled voltages are fed back to feedback control module 60 and process, feedback control module 60 is using the minimum of a value in all sampled voltages as benchmark, export the minimum of a value in all sampled voltages to DC/DC control module 30, DC/DC control module 30, according to minimum sampled voltage, exports drive control signal to control the boosting ratio of boost module 20; Simultaneously, feedback control module 60, according to the size of all sampled voltages, outputs control signals to constant current adjusting module 50, to control the electric current that constant current adjusting module 50 adjusts every paths of LEDs string in LED strip module 40, make the electric current of every paths of LEDs string equal, the luminosity realizing every paths of LEDs string is equal.
With reference to Fig. 4 and Fig. 5, wherein Fig. 5 is the electrical block diagram of multi-channel LED constant current control circuit preferred embodiment of the present invention.
In above-described embodiment, boost module 20 comprises inductance L 1, diode D1, electric capacity C1 and switching tube M0; One end of inductance L 1, as the input of boost module 20, is connected with supply module 10, and the other end of inductance L 1 is connected with the anode of diode D1, and the other end of inductance L 1 is connected with the drain electrode of switching tube M0; The grid of switching tube M0 is connected with the output of DC/DC control module 30, the source ground of switching tube M0; The negative electrode of diode D1 is through electric capacity C1 ground connection, and the negative electrode of diode D1 is connected with the input of each paths of LEDs string respectively.
In the present embodiment, the topological structure forming Boost circuit by inductance L 1, diode D1, electric capacity C1 and switching tube M0, boosts the input voltage inputted from supply module 10 according to set boosting ratio, to realize the adjustment to output voltage.
Particularly, the switching tube M0 in boost module 20 is NMOS tube.
Composition graphs 4 to Fig. 6, wherein Fig. 6 is the internal circuit configuration schematic diagram of DC/DC control chip 301 in multi-channel LED constant current control circuit of the present invention.
In above-described embodiment, DC/DC control module 30 comprises DC/DC accessory power supply VCC and DC/DC control chip 301, the positive pole of DC/DC accessory power supply VCC is connected with the power end of DC/DC control chip 301, and the negative pole of DC/DC accessory power supply VCC is connected with the earth terminal of DC/DC control chip 301.DC/DC accessory power supply VCC provides operating voltage for DC/DC control module 30.
Particularly, DC/DC control chip 301 comprises reference power supply V_REF, error amplifier AMP1, comparator COMP1 and driver element DRV1; The positive pole of reference power supply V_REF is connected with the in-phase input end of error amplifier AMP1, the minus earth of reference power supply V_REF, and reference power supply V_REF provides reference voltage V ref for error amplifier AMP1; The output of error amplifier AMP1 is connected with the inverting input of comparator COMP1; The in-phase input end of comparator COMP1 is connected with sawtooth waveforms input STW, and the output of comparator COMP1 is connected with the input of driver element DRV1; The output of driver element DRV1, as the drive output DRIVER of DC/DC control module 30, is connected with the grid of switching tube M0.
In above-described embodiment, each paths of LEDs string comprises some series connection and the identical LED of conducting direction, the present embodiment is described for 3 paths of LEDs strings, as in Fig. 5, first via LED strip 401 comprises N number of series connection and the identical LED LED11 ~ LED1N of conducting direction, second paths of LEDs string 402 comprises N number of series connection and the identical LED LED21 ~ LED2N of conducting direction, 3rd paths of LEDs string 403 comprises N number of series connection and the identical LED LED31 ~ LED3N of conducting direction, wherein N is positive integer, the anode tap of each paths of LEDs string is as the input of each paths of LEDs string, all be connected with the negative electrode of diode D1.
When regulating the electric current of each paths of LEDs string, adopt current minimum as benchmark, the electric current in each paths of LEDs string is compared with current minimum, and then regulates the electric current in each paths of LEDs string, make the electric current in every paths of LEDs string equal with current minimum, the electric current realized in every paths of LEDs string is equal.
In above-described embodiment, constant current adjusting module 50 comprises at least two the constant current adjustment units corresponding with LED strip, and the input of each constant current adjustment unit is connected with the cathode terminal of a LED strip.The present embodiment is also described for 3 constant current adjustment units, as in Fig. 5, the input of the first constant current adjustment unit 501 is connected with the cathode terminal of the first LED strip 401, the input of the second constant current adjustment unit 502 is connected with the cathode terminal of the second LED strip 402, and the input of the 3rd constant current adjustment unit 503 is connected with the cathode terminal of the 3rd LED strip 403.
Particularly, each constant current adjustment unit comprises Correctional tube, sampling resistor, operational amplifier and two-way selector.As shown in Figure 5, first constant current adjustment unit 501 comprises the first Correctional tube M1, the first sampling resistor RS1, the first operational amplifier OP1 and the first two-way selector MUX1, second constant current adjustment unit 502 comprises the second Correctional tube M2, the second sampling resistor RS2, the second operational amplifier OP2 and the second two-way selector MUX2, and the 3rd constant current adjustment unit 503 comprises the 3rd Correctional tube M3, the 3rd sampling resistor RS3, the 3rd operational amplifier OP3 and the 3rd two-way selector MUX3.The structure of the first constant current adjustment unit 501, second constant current adjustment unit 502 and the 3rd constant current adjustment unit 503 and all identical with the annexation of other modules, is described for the first constant current adjustment unit 501 below:
The drain electrode of the first Correctional tube M1 is as the input of the first constant current adjustment unit 501, be connected with the cathode terminal of the first LED strip 401, the source electrode of the first Correctional tube M1 is through the first sampling resistor RS1 ground connection, and the source electrode of the first Correctional tube M1 is connected with the inverting input of the first operational amplifier OP1 and an input pin of feedback control module 60 respectively, the grid of the first Correctional tube M1 is connected with the output of the first operational amplifier OP1; The in-phase input end of the first operational amplifier OP1 is connected with the output of the first two-way selector MUX1; The first input end of the first two-way selector MUX1 is connected with an output pin of feedback control module 60, and the first input end of the first two-way selector MUX1 is connected with the inverting input of error amplifier AMP1, the inverting input of error amplifier AMP1 is as the feedback input end ISEN of DC/DC control module 30, second input of the first two-way selector MUX1 is connected with the positive pole of reference power supply V_REF, and the control end of the first two-way selector MUX1 is connected with another output pin of feedback control module 60.
In the present embodiment, feedback control module 60 is an IC chip, there are multiple output pins of the multiple input pin as the input of feedback control module 60 and the output as feedback control module 60, and the built-in detection short circuit of feedback control module 60 and function of open, when having the short circuit of a certain paths of LEDs string or open circuit, the electric current of this paths of LEDs string does not compare with current minimum, avoid when having LED strip short circuit or open circuit, cause the maloperation of feedback control module 60, affect constant current adjustment result.
Particularly, the Correctional tube in each constant current adjustment unit is NMOS tube, and namely the first Correctional tube M1, the second Correctional tube M2 and the 3rd Correctional tube M3 adopt NMOS tube.The present embodiment preferably adopts NMOS tube as Correctional tube, utilizes Correctional tube to regulate the electric current of every paths of LEDs string.What deserves to be explained is in addition, PMOS, PNP triode or NPN triode can also be selected as Correctional tube, just for PMOS and PNP triode, need to change itself and operational amplifier, and the annexation of operational amplifier and two-way selector, such as select PMOS, for the first constant current adjustment unit 501, above-mentioned annexation should be: the drain electrode of the first PMOS is through the first sampling resistor RS1 ground connection, and be connected with the in-phase input end of the first operational amplifier OP1, the source electrode of the first PMOS is connected with the cathode terminal of the first LED strip 401; The inverting input of the first operational amplifier OP1 is connected with the output of the first two-way selector MUX1.
The operation principle of multi-channel LED constant current control circuit of the present invention specifically describes as follows:
First it should be noted that, the embodiment of the present invention is when regulating the electric current of each paths of LEDs string, the minimum of a value of electric current, maximum or median can be adopted to regulate as benchmark, the embodiment of the present invention preferably adopts the minimum of a value of electric current as benchmark, therefore adopt minimum of a value in all sampled voltages produced at each paths of LEDs string as benchmark, namely adopt minimum sampled voltage Vmin as benchmark.Below to adopt minimum sampled voltage Vmin to be described as benchmark.
The input voltage VIN inputted from supply module 10 exports the voltage after boosting after boost module 20 boosts by default boosting ratio, i.e. output voltage VO UT, output voltage VO UT is input in each paths of LEDs string respectively, drives the LED in each paths of LEDs string to light.Wherein, the dutycycle D of the drive control signal that the boosting ratio of boost module 20 is exported by DC/DC control module 30 breaker in middle pipe M0 grid determines, the relational expression that the dutycycle D of input voltage VIN, output voltage VO UT and drive control signal meets is: D=1-VIN/VOUT.As can be seen from formula, the dutycycle D of drive control signal is larger, and output voltage VO UT is higher.
The electric current flowing through each paths of LEDs string produces sampled voltage on sampling resistor, as label V1, V2 and V3 in Fig. 5, electric current I 1 in first via LED strip 401 produces the first sampled voltage V1 on the first sampling resistor RS1, electric current I 2 in second paths of LEDs string 402 produces the second sampled voltage V2 on the second sampling resistor RS2, and the electric current I 3 in the 3rd paths of LEDs string 403 produces the 3rd sampled voltage V3 on the 3rd sampling resistor RS3.
The the first sampled voltage V1 produced, the second sampled voltage V2 and the 3rd sampled voltage V3 are fed back to three inputs of feedback control module 60 respectively, are processed by feedback control module 60.As label Vmin, ctrl1, ctrl2 and ctrl3 in Fig. 5, feedback control module 60 selects minimum sampled voltage Vmin in the first sampled voltage V1, the second sampled voltage V2 and the 3rd sampled voltage V3 to export by an output, outputs to the first input end of the feedback input end ISEN of DC/DC control module 30, the first input end of the first two-way selector MUX1, the first input end of the second two-way selector MUX2 and the 3rd two-way selector MUX3 respectively; Simultaneously, export the first control signal ctrl1, the second control signal ctrl2 respectively at other three outputs of feedback control module 60, the 3rd control signal ctrl3, the first control signal ctrl1, the second control signal ctrl2, the 3rd control signal ctrl3 outputted to the control end of the first two-way selector MUX1, the control end of the second two-way selector MUX2 and the control end of the 3rd two-way selector MUX3 respectively.
First two-way selector MUX1, the second two-way selector MUX2 and the 3rd two-way selector MUX3, according to the level state of the first control signal ctrl1, the second control signal ctrl2, the 3rd control signal ctrl3, select to export minimum sampled voltage Vmin or reference voltage V ref to the first operational amplifier OP1, the second operational amplifier OP2 and the 3rd operational amplifier OP3.
In the present embodiment, if the sample voltage value that a certain paths of LEDs string produces is minimum of a value, then the control signal exporting this paths of LEDs string to is high level, and the control signal exporting other roads to is low level.Such as: if the first sampled voltage V1 is minimum of a value, then the first control signal ctrl1 is high level, the second control signal ctrl2, the 3rd control signal ctrl3 are low level; Because the first control signal ctrl1 is high level, therefore in the first two-way selector MUX1 output reference voltage Vref to the first operational amplifier OP1, in first operational amplifier OP1, the difference of reference voltage V ref and the first sampled voltage V1 is amplified, difference after amplification controls the first Correctional tube M1, make the first sampled voltage V1 strict equal reference voltage V ref; Second control signal ctrl2 is low level, second two-way selector MUX2 exports in minimum sampled voltage Vmin to the second operational amplifier OP2, the difference of minimum sampled voltage Vmin and the second sampled voltage V2 is amplified by the second operational amplifier OP2, difference after amplification controls the second Correctional tube M2, make the second sampled voltage V2 strict equal minimum sampled voltage Vmin; What in like manner the 3rd sampled voltage V3 was strict equals minimum sampled voltage Vmin; Because the first sampled voltage V1 is minimum of a value, so V1=V2=V3=Vref, the resistance of the first sampling resistor RS1, the second sampling resistor RS2 and the 3rd sampling resistor RS3 is equal, i.e. RS1=RS2=RS3, so the electric current I 1=I2=I3=Vref/RS1 in each paths of LEDs string, thus the electric current of each paths of LEDs string just can be equal.In practical application, because reference voltage V ref is produced by built-in reference power supply V_REF in DC/DC control module 30, can not change, and the first sampling resistor RS1, the second sampling resistor RS2 and the 3rd sampling resistor RS3 are non-essential resistances, therefore can change electric current in each paths of LEDs string by selecting the resistance of the first sampling resistor RS1, the second sampling resistor RS2 and the 3rd sampling resistor RS3, reaching and regulating the electric current in each paths of LEDs string to make its accurately equal object.
In DC/DC control module 30, error amplifier AMP1 amplifies the difference of the minimum sampled voltage Vmin and reference voltage V ref inputted from feedback input end ISEN, difference after amplification compares with the sawtooth signal inputted from sawtooth waveforms input STW, export a string square-wave signal, square-wave signal exports drive control signal to switching tube M0 through over-drive unit DRV1, improve the driving force of switch tube M0, control boost module 20 regulation output voltage VOUT.
In embodiments of the present invention, feedback voltage equals minimum sampled voltage Vmin, so be at Vref/RS1 the current-clamp of the LED strip at minimum sampled voltage Vmin place (as the first LED strip 401), the electric current of all the other LED strip then needs to be adjusted by Correctional tube, makes current difference between every paths of LEDs string be reduced to minimum.
What deserves to be explained is, owing to causing the unequal factor of the electric current mainly sampling resistor between each paths of LEDs string, as long as therefore the precision of sampling resistor is ± 1%, then the current precision of each paths of LEDs string be also substantially ± 1%.
The multi-channel LED constant current control circuit that the present invention proposes, LED strip module 40 is exported to after being boosted by the input voltage inputted from supply module 10 by boost module 20, the electric current flowing through each paths of LEDs string produces a sampled voltage in the constant current adjustment unit of correspondence, by the control of feedback control module 60, minimum sampled voltage is fed back to DC/DC control module 30, to control the boosting ratio of boost module 20, regulation output voltage; Simultaneously, adopt minimum current in each paths of LEDs string as benchmark, control signal is exported to constant current adjusting module 50 by feedback control module 60, different voltage references selected by the two-way selector controlled in each constant current adjustment unit, make the electric current of remaining LED strip be all that benchmark is regulated by Correctional tube with minimum current, and then make the electric current of every paths of LEDs string equal, the luminosity realizing every paths of LEDs string is equal, improve the precision of current constant control, strengthen the uniformity of LED luminosity.
The present invention also proposes a kind of LED light source control system, this LED light source control system comprises multi-channel LED constant current control circuit, the circuit structure of this multi-channel LED constant current control circuit is identical with operation principle with the circuit structure of the multi-channel LED constant current control circuit described in above-described embodiment with operation principle, repeats no more herein.
The foregoing is only the preferred embodiments of the present invention; not thereby the scope of the claims of the present invention is limited; every utilize description of the present invention and accompanying drawing content to do equivalent structure or equivalent flow process conversion; or be directly or indirectly used in other relevant technical fields, be all in like manner included in scope of patent protection of the present invention.
Claims (7)
1. a multi-channel LED constant current control circuit, comprise supply module, the boost module for being carried out boosting by input voltage, the DC/DC control module and the LED strip module that are used for controlling described boost module boosting ratio, described LED strip module comprises at least two paths of LED string, it is characterized in that, described multi-channel LED constant current control circuit also comprises the constant current adjusting module of the electric current for adjusting LED strip described in each road and the feedback control module for controlling described constant current adjusting module adjustment electric current; Wherein:
The input of described boost module is connected with described supply module, output is connected with the input of described LED strip module, the output of described LED strip module is connected with the input of described constant current adjusting module, the output of described constant current adjusting module is connected with the input of described feedback control module, the output of described feedback control module is connected with the feedback input end of described DC/DC control module and the control end of described constant current adjusting module respectively, and the drive output of described DC/DC control module is connected with the control end of described boost module;
Described boost module comprises switching tube, and described DC/DC control module comprises DC/DC control chip, and described DC/DC control chip comprises reference power supply, error amplifier, comparator and driver element; The positive pole of described reference power supply is connected with the in-phase input end of described error amplifier, the minus earth of described reference power supply; The output of described error amplifier is connected with the inverting input of described comparator; The in-phase input end of described comparator is connected with sawtooth waveforms input, and the output of described comparator is connected with the input of described driver element; The output of described driver element, as the drive output of described DC/DC control module, is connected with the grid of described switching tube;
Described constant current adjusting module comprises at least two the constant current adjustment units corresponding with described LED strip, and the input of constant current adjustment unit described in each is connected with the cathode terminal of LED strip described in;
Constant current adjustment unit described in each comprises Correctional tube, sampling resistor, operational amplifier and two-way selector; Wherein:
The drain electrode of described Correctional tube is as the input of described constant current adjustment unit, connect with the cathode terminal of LED strip described in corresponding, the source electrode of described Correctional tube is through described sampling resistor ground connection, and be connected with the inverting input of described operational amplifier and an input pin of described feedback control module respectively, the grid of described Correctional tube is connected with the output of described operational amplifier; The in-phase input end of described operational amplifier is connected with the output of described two-way selector; The first input end of described two-way selector is connected with an output pin of described feedback control module, and be connected with the inverting input of described error amplifier, second input of described two-way selector is connected with the positive pole of described reference power supply, and the control end of described two-way selector is connected with another output pin of described feedback control module.
2. multi-channel LED constant current control circuit as claimed in claim 1, it is characterized in that, described boost module also comprises inductance, diode and electric capacity; One end of described inductance, as the input of described boost module, is connected with described supply module, and the other end of described inductance is connected with the anode of described diode, and is connected with the drain electrode of described switching tube, the source ground of described switching tube; The negative electrode of described diode through described capacity earth, and is connected with the input of LED strip described in each road respectively.
3. multi-channel LED constant current control circuit as claimed in claim 2, it is characterized in that, described switching tube is NMOS tube.
4. multi-channel LED constant current control circuit as claimed in claim 2, it is characterized in that, described DC/DC control module also comprises DC/DC accessory power supply, the positive pole of described DC/DC accessory power supply is connected with the power end of described DC/DC control chip, and the negative pole of described DC/DC accessory power supply is connected with the earth terminal of described DC/DC control chip.
5. multi-channel LED constant current control circuit as claimed in claim 2, is characterized in that, LED strip described in each road comprises some series connection and the identical LED of conducting direction, and described in each road, the anode tap of LED strip is all connected with the negative electrode of described diode.
6. multi-channel LED constant current control circuit as claimed in claim 1, it is characterized in that, described Correctional tube is NMOS tube.
7. a LED light source control system, is characterized in that, comprises the multi-channel LED constant current control circuit according to any one of claim 1 to 6.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310003575.4A CN103037597B (en) | 2013-01-06 | 2013-01-06 | Multi-channel LED (Light Emitting Diode) constant current control circuit and LED light source control system |
| HK13110571.1A HK1183399A1 (en) | 2013-01-06 | 2013-09-13 | Multi-channel led (light emitting diode) constant current control circuit and led light source control system led led |
Applications Claiming Priority (1)
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| CN201310003575.4A CN103037597B (en) | 2013-01-06 | 2013-01-06 | Multi-channel LED (Light Emitting Diode) constant current control circuit and LED light source control system |
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| CN103037597B true CN103037597B (en) | 2015-03-25 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105246191A (en) * | 2015-09-09 | 2016-01-13 | 重庆平伟光电科技有限公司 | LED light control device for plant illumination light source light distribution and control method |
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| CN104284474B (en) * | 2013-07-10 | 2017-08-15 | 戴泺格集成电路（天津）有限公司 | LED driver controller, LED driver and LED driving methods |
| CN103458578B (en) * | 2013-08-27 | 2015-05-13 | 青岛海信电器股份有限公司 | Light-emitting diode (LED) driving system and method and LED display device |
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| CN103874296B (en) * | 2014-03-21 | 2016-09-14 | 武汉精测电子技术股份有限公司 | The constant current driver circuit for LED of multichannel self-adapting load |
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| CN109152132B (en) * | 2018-08-16 | 2019-12-03 | 西安电子科技大学 | A kind of LED multi-path light adjusting circuit |
| CN111796150B (en) * | 2019-04-08 | 2023-09-22 | 华润微集成电路(无锡)有限公司 | Duty cycle detection circuit and duty cycle detection method |
| CN112233625B (en) * | 2020-10-16 | 2024-02-09 | Tcl华星光电技术有限公司 | Backlight constant current control circuit and backlight structure |
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| CN101494938A (en) * | 2009-02-19 | 2009-07-29 | 英飞特电子（杭州）有限公司 | Centralization type light change circuit for LED illuminating system |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201657405U (en) * | 2010-01-05 | 2010-11-24 | 英飞特电子（杭州）有限公司 | Circuit applicable to current-sharing control on multiple LEDs |
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- 2013-01-06 CN CN201310003575.4A patent/CN103037597B/en active Active
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101494938A (en) * | 2009-02-19 | 2009-07-29 | 英飞特电子（杭州）有限公司 | Centralization type light change circuit for LED illuminating system |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105246191A (en) * | 2015-09-09 | 2016-01-13 | 重庆平伟光电科技有限公司 | LED light control device for plant illumination light source light distribution and control method |
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| CN103037597A (en) | 2013-04-10 |
| HK1183399A1 (en) | 2013-12-20 |
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