CN105934029B - A kind of multipath LED constant current drive circuit - Google Patents
A kind of multipath LED constant current drive circuit Download PDFInfo
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- CN105934029B CN105934029B CN201610367582.6A CN201610367582A CN105934029B CN 105934029 B CN105934029 B CN 105934029B CN 201610367582 A CN201610367582 A CN 201610367582A CN 105934029 B CN105934029 B CN 105934029B
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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]
- H05B45/30—Driver circuits
- H05B45/37—Converter circuits
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
- Y02B20/30—Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]
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Abstract
The invention discloses a kind of multipath LED constant current drive circuit, including voltage regulator, LED channel array and feedback control unit.Feedback control unit includes a MUX, one error amplifier and a comparator, pulse unit is by controlling MUX come the sampled voltage input feedback control circuit of timesharing wherein one LED branch road of selection, the work of feedback control signal control voltage adjuster is produced, realizes the purpose for accurately controlling each LED branch current.By using an error amplifier, while make every LED branch road sampling resistor resistance identical to realize every LED branch current of control, the uniformity of voltage.The present invention realizes the purpose of the same feedback control circuit of time-sharing multiplex by impulse circuit, simplifies feedback circuit elements number and circuit structure.Error amplifier reduces the pressure drop on current regulating circuit, reduces circuit loss.
Description
Technical field
The invention belongs to electronic technology field, further relates to a kind of multipath LED constant current in electric and electronic technical field
Drive circuit.The present invention can be used for realizing that multipath LED constant current drives.
Background technology
Illuminating with backlight application, often by multi-way LED lamp connection in series-parallel application, including one or more per paths of LEDs lamp string
The individual LED being connected in series, the luminous intensity of each LED are determined by the electric current for flowing through LED, therefore use electric current in applying
Regulation circuit flows through the electric current of LED string to control.Simultaneously because the difference of characteristic in itself per paths of LEDs lamp string be present, in practice
When flowing through identical electric current per paths of LEDs lamp string, its conduction voltage drop can be differed, therefore the current regulating circuit of different branch can be held
By different input voltages, it is therefore desirable to the output end voltage of voltage regulator is adjusted to reduce electricity using feedback unit
Pressure drop on stream regulation circuit, reduces circuit loss.
University of Electronic Science and Technology is in a kind of its patent application document " multi-channel LED array drive circuit " (application publication number CN
104254181 A, application number 201110310792.9, application number 201410474880.6, date of application 2014.12.31) in it is public
A kind of multi-channel LED array drive circuit is opened, the circuit includes BUCK drive circuits, LED channel array parallel with one another, connected
It is connected on BUCK drive circuits, and is driven by BUCK drive circuits；Feedback control circuit, its input are connected to LED channel battle array
Row, output end are connected to the control signal of BUCK drive circuits, electric to control BUCK to drive for producing feedback control signal
The work on road.Voltage follower is provided between two adjacent LEDs branch road in LED channel array, voltage follower ensure that often
Bar channel voltage, the uniformity of electric current, realize LED branch roads and flow.Circuit is traditional BUCK mode driving circuits and constant current
Drive circuit under pattern is combined, and controls BUCK converters using voltage mode, the voltage-type switch-mode regulation control system is
The automatic control system of monocyclic feedback, which is simply, stably, it is ensured that the good precision of voltage regulation.Existing for the circuit not
It is in place of foot：Circuit reaches the purpose that control LED multi-path string flows by multiple voltage-stablizers, and circuit structure is complicated, parts number
Mesh is more, and loss is big.
Nanjing silicon Cenda Semiconductor Co., Ltd is in its patent application document " a kind of multipath LED constant current circuit and its driving
Method " (A of application publication number CN 104883793, application number 201510313704.9, date of application 2015.09.02) discloses
A kind of multipath LED constant current circuit drives circuit.Multiple signals generation circuit is according to the current regulating circuit per road in the circuit
The difference of input voltage signal, different reference current signals and duty cycle adjustment signal are produced, current regulating circuit is according to base
The peak value of quasi- current signal control LED string electric current, makes peak value consistent with reference current signal, then current regulating circuit according to
Duty cycle adjustment signal controls the average value of LED string electric current so that the average value of LED string electric current is with it is expected operating current one
Cause.Pass through above-mentioned control program so that in the case where current regulating circuit bears larger pressure drop, control the pressure of LED string
Falling-rising is high, to reduce the pressure drop of current regulating circuit, so as to reduce loss, meanwhile, control the current average of LED string not
Become, ensure that LED string is able to maintain that normal work.The circuit reaches regulation multi-way LED lamp by multichannel current regulating circuit
The purpose of string electric current, while reached by voltage feedback unit, multiple signals generation circuit and smallest end voltage generation circuit
The pressure drop of voltage regulation unit is reduced, drops low-loss purpose.Weak point existing for the circuit is：Circuit passes through multichannel electric current
Adjuster reaches the purpose that flows of control LED multi-path string, and circuit structure is complicated, loss is big；In order that multichannel adjuster is normal
Work and reach the purpose of the electric current for it is expected LED string to realize, the pressure drop on multichannel adjuster is usually larger numerical value, generally
The scope of pressure drop on current regulating circuit is 0.5~1V, and the loss of current regulating circuit is larger.Using voltage feedback unit,
Multiple signals generation circuit and smallest end voltage generation circuit reduce the pressure drop of voltage regulation unit to reach, and drop low-loss mesh
, circuit structure is complicated, and loss is big.
" high efficiency LED driving multiple-channel output mixed strategy research " that Zhao Rongrong, Zhang Junming are delivered (electromechanical engineering,
2015.06：A kind of efficiently LED multi-path output based on quasi- two-dimensional transform device 1-7) is proposed in paper and mixes equal Flow Policy.
Mixing flow equalizing circuit is made up of multiple independent output modules, using the characteristic of balancing capacitance charge conservation to two-way in module
LED output currents are efficiently balanced, and the DC-DC current regulators between separate output module using Partial Power processing are real
Existing current balance, the current regulator in Partial Power processing structure are operated in the state of low-voltage high-frequency to obtain higher effect
Rate, lower cost.The circuit carries out the accurate equal of intermodule by each output module one DC/DC current regulator of series connection
Stream.The problem of circuit disclosed in this paper is present be：Circuit reaches control LED multi-path string by multiple current regulators
The purpose flowed, circuit structure is complicated, and loss is big.
The content of the invention
In order to overcome above-mentioned problems of the prior art, a kind of multipath LED constant current drive circuit is proposed, can be simplified
Circuit structure, circuit loss is reduced, improve constant current accuracy.
The present invention includes voltage regulator, LED channel array and feedback control unit, the output end of voltage regulator and
First input port of LED channel array is connected, second input port of LED channel array and first of pulse unit
Output port is connected, and the output end of LED channel array is connected with the first of feedback control unit input port, feedback control list
Second input port of member is connected with second output port of pulse unit, the output port and voltage of feedback control unit
The input of adjuster is connected；Wherein,
Voltage regulator, voltage regulator is adjusted for receiving feedback control signal, and according to the feedback control signal
Output voltage.
LED channel array includes three LED branch roads, and each LED branch roads include the LED of at least two series connection, three LED branch
It is connected after the parallel connection of road with the output end of voltage regulator；Every LED branch road is adopted including a metal-oxide-semiconductor, a LED string, one
Sample resistance, sampling resistor resistance in three LED branch roads in parallel with electric capacity after metal-oxide-semiconductor, LED string, sampling resistor are sequentially connected in series
It is identical.
First output port of pulse unit is connected to the grid of first LED branch road metal-oxide-semiconductor, for controlling first
LED branch roads；Second output port of pulse unit is connected to the grid of Article 2 LED branch road metal-oxide-semiconductors, for controlling Article 2
LED branch roads；3rd output port of pulse unit is connected to the grid of Article 3 LED branch road metal-oxide-semiconductors, for controlling Article 3
LED branch roads.
First input port of feedback control unit is connected to the output end of LED channel array, feedback control unit
Second input port is connected to second output port of pulse unit, and the output end of feedback control unit is connected to voltage tune
Save the input of device；Feedback control unit includes a MUX, an error amplifier and a comparator, more than one
Road selector, an error amplifier and a comparator are sequentially connected in series, for producing feedback control signal control voltage
Adjuster works.
First output port of pulse unit is connected to first input port A of MUX1, it is defeated for selecting
Go out the sampled voltage of first LED branch road；Second output port of pulse unit be connected to MUX second is defeated
Inbound port A2, for selecting the sampled voltage of output Article 2 LED branch roads；3rd output port of pulse unit is connected to more
3rd input port A of road selector3, for selecting the sampled voltage of output Article 3 LED branch roads.
Pulse unit includes one two input and gate circuit, three d type flip flops, described one two input and gate circuit,
Three d type flip flops are sequentially connected, for producing pulse signal control LED channel array and feedback control unit work.
The present invention has the following advantages that compared with prior art：
First, because the present invention using first output port of pulse unit is connected to first LED branch road metal-oxide-semiconductor
Grid, for controlling first LED branch road, second output port of pulse unit is connected to Article 2 LED branch road metal-oxide-semiconductors
Grid, for controlling Article 2 LED branch roads, the 3rd output port of pulse unit is connected to Article 3 LED branch road metal-oxide-semiconductors
Grid, for controlling Article 3 LED branch roads, so as to control the timesharing of LED branch road metal-oxide-semiconductors to turn on.First output of pulse unit
Port is connected to first input port A of MUX1, for selecting the sampled voltage of first LED branch road of output defeated
Enter to feedback control circuit, second output port of pulse unit and be connected to second input port A of MUX2,
For selecting the sampled voltage of output Article 2 LED branch roads to be input to feedback control circuit, the 3rd output end of pulse unit
Mouth is connected to the 3rd input port A of MUX3, for selecting the sampled voltage input of output Article 3 LED branch roads
To feedback control circuit, realize that the same feedback control unit of time-sharing multiplex controls three LED branch roads, control every LED branch road
The purpose of electric current, the problem of overcoming circuit structure complexity caused by needing multichannel current regulating circuit in the prior art so that
This invention simplifies circuit structure and component number, reduces circuit loss.
Second, due to using the sampling resistor of similar resistance in every LED branch road of the invention, feedback control unit uses one
Individual error amplifier, thus same reference voltage is used, it ensure that all first port voltages of LED branch roads sampling resistor
Uniformity, every LED branch voltage, the uniformity of electric current are ensure that, overcome and use multiple voltage regulators in the prior art
The problem of ensureing the uniformity of every LED branch voltage, electric current, circuit structure is simplified, reduce loss.
3rd, due to using an error amplifier, error amplifier in-phase input end in feedback control unit of the present invention
Reference voltage can take and do compared with fractional value, overcome needs to keep LED string normal in the prior art on current regulation unit
The problem of pressure drop is big on current regulating circuit caused by work, realizing reduces circuit loss, while ensures the normal work of LED string
The purpose of work.
Brief description of the drawings
Fig. 1 is the block diagram of the present invention；
Fig. 2 is the circuit theory diagrams of the present invention；
Fig. 3 is the oscillogram of the circuit course of work of the present invention.
Embodiment
The present invention is described in detail below in conjunction with the accompanying drawings.
Reference picture 1 is explained in detail to the unit of the present invention.
The present invention includes voltage regulator, LED channel array and feedback control unit, the output end of voltage regulator and
The a port of LED channel array is connected.Voltage regulator, voltage regulator can use booster type voltage regulator or decompression
Type voltage regulator, for receiving feedback control signal, and according to the output of feedback control signal regulation voltage regulator
Voltage.First input port of LED channel array is connected with the output end of voltage regulator, second of LED channel array
Input port is connected with the output end of pulse unit, the output end of LED channel array and the first of feedback control unit input
Port is connected, and second input port of feedback control unit is connected with the output end of pulse unit, feedback control unit it is defeated
Go out end with the input of voltage regulator to be connected, for producing the work of feedback control signal control voltage adjuster.Impulse circuit
Output end second input port with feedback control circuit, second input port of LED channel array are connected respectively, use
LED channel array and feedback control unit work are controlled in producing pulse signal.
Reference picture 2 is described in detail to the specific annexation of component in the electrical schematic diagram of the present invention.
The output end of voltage regulator is connected with first input port of LED channel array.The first of LED channel array
Individual input port is connected with the output end of voltage regulator, second input port and feedback control unit of LED channel array
First input port be connected, LED channel array includes three LED branch roads, and each LED branch roads include at least two series connection
LED, it is connected with the output end of voltage regulator after three LED branch circuit parallel connections；Every LED branch roads include metal-oxide-semiconductor, one
Bar LED string, a sampling resistor, described metal-oxide-semiconductor, LED string, sampling resistor are in parallel with electric capacity after being sequentially connected in series, three
Sampling resistor resistance in LED branch roads is identical.
A metal-oxide-semiconductor, a LED string, a sampling resistor in every branch road are sequentially connected in series in parallel with electric capacity afterwards
Structure is as follows：
Metal-oxide-semiconductor M in first LED branch road1Source electrode be connected to the output end of the voltage regulator, grid is connected to
First output end of pulse unit, drain electrode are connected respectively to a port of the LED string in first article of LED branch road, electricity
Hold C1A port, electric capacity C1Second port ground connection, second port of LED string and sampling resistor R1First
Individual port is connected, and second port ground connection of sampling resistor, LED string is connected with sampling resistor, sampling resistor R1First
Port exports the sampled voltage of first LED branch road.
Article 2 LED branch road metal-oxide-semiconductors M2Source electrode be connected to the output end of the voltage regulator, grid is connected to pulse
Second output end of unit, drain electrode are connected respectively to a port of the LED string in Article 2 LED branch roads, electric capacity C2
A port, electric capacity C2Second port ground connection, second port of LED string and sampling resistor R2First end
Mouth is connected, and second port ground connection of sampling resistor, LED string is connected with sampling resistor, sampling resistor R2A port
Export the sampled voltage of Article 2 LED branch roads.
Article 3 LED branch road metal-oxide-semiconductors M3Source electrode be connected to the output end of the voltage regulator, grid is connected to pulse
3rd output end of unit, drain electrode are connected respectively to a port of the LED string in Article 3 LED branch roads, electric capacity C3
A port, electric capacity C3Second port ground connection, second port of LED string and sampling resistor R3First end
Mouth is connected, and second port ground connection of sampling resistor, LED string is connected with sampling resistor, sampling resistor R3A port
Export the sampled voltage of Article 3 LED branch roads.
First input port of feedback control unit is connected to the output end of pulse unit, and the second of feedback control unit
Individual input port is connected to the output end of LED channel array, and the output end of feedback control unit is connected to the defeated of voltage regulator
Enter end；Feedback control unit includes a MUX, an error amplifier and a comparator, a multi-path choice
Device, an error amplifier and a comparator are sequentially connected in series, for producing feedback control signal control voltage adjuster
Work.
A MUX in feedback control unit, an error amplifier and a comparator are sequentially connected in series
Structure it is as follows：
First input port A of MUX1First output port of pulse unit is connected to, it is defeated for selecting
Go out the sampled voltage of first LED branch road；Second input port A of MUX2It is connected to second of pulse unit
Output port, for selecting the sampled voltage of output Article 2 LED branch roads；3rd input port A of MUX3Connection
To the 3rd output port of pulse unit, for selecting the sampled voltage of output Article 2 LED branch roads；The of MUX
Four input port S2It is connected to first LED branch road sampling resistors R1A port, the 5th of MUX input
Port S3It is connected to Article 2 LED branch road sampling resistors R2A port, the 6th input port S of MUX5Even
It is connected to Article 3 LED branch road sampling resistors R3A port.
The inverting input of error amplifier is connected to the output end of MUX, the in-phase input end of error amplifier
It is connected to reference voltage.
The in-phase input end of comparator is connected with the output end of error amplifier, and the inverting input of comparator is connected to tiltedly
Slope generator.
One two input and gate circuit in pulse unit, three d type flip flops are sequentially connected, for producing pulse signal control
LED channel array and feedback control unit work processed.One two in pulse unit input and gate circuit, three d type flip flops according to
The structure of secondary connection is as follows, and first output port Q1 of first d type flip flop be connected to second d type flip flop first is defeated
Inbound port D2, first output port Q2 of second d type flip flop are connected to first input port of the 3rd d type flip flop
D3, second output port Q1 of first d type flip flop are connected to first input port of two inputs and door, and second D is touched
Second output port Q2 of hair device is connected to second input port of two inputs and door, and two inputs are connected with the output end of door
To first input port D1 of first d type flip flop, second input port clk1 of first d type flip flop, second D are touched
Second input port clk2 of device is sent out, second input port clk3 of first d type flip flop is connected to clock generation circuit.
Reference picture 3 protects protected power tube process to be explained in detail the present invention.
During the output end signal B1 output high level of first d type flip flop in the pulse unit in figure three, first LED
The metal-oxide-semiconductor conducting of branch road, voltage regulator is to first LED branch road electric capacity C1Discharge and recharge is carried out, the I1 in figure three is electric capacity C1's
Current waveform figure, first input end signal A1 signal of MUX is high level, selects the sampling of first LED branch road
Ohmically sampled voltage is input to the inverting input of error amplifier, and the setting with error amplifier in-phase input end refers to
Voltage Vref is compared, and the error signal after amplification is subsequently inputted into the inverting input of comparator, same with comparator
The sawtooth signal Vsaw that phase input is set is compared, and produces the work that feedback control signal carrys out control voltage adjuster
Make.During the output end signal B2 output high level of second d type flip flop in the pulse unit in figure three, Article 2 LED branch roads
Metal-oxide-semiconductor conducting, voltage regulator is to first LED branch road electric capacity C2Discharge and recharge is carried out, the I2 in figure three is electric capacity C2Electric current
Oscillogram, while second input end signal A2 signal of MUX is high level, selects the sampling of Article 2 LED branch roads
Ohmically sampled voltage is input to the inverting input of error amplifier, and the setting with error amplifier in-phase input end refers to
Voltage Vref is compared, and the error signal after amplification is subsequently inputted into the inverting input of comparator, same with comparator
The sawtooth signal Vsaw that phase input is set is compared, and produces the work that feedback control signal carrys out control voltage adjuster
Make.During the output end signal B3 output high level of the 3rd d type flip flop in the pulse unit in figure three, Article 3 LED branch roads
Metal-oxide-semiconductor conducting, voltage regulator is to Article 3 LED branch road electric capacity C3Discharge and recharge is carried out, the I3 in figure three is electric capacity C3 electricity
Oscillogram is flowed, while the 3rd input end signal A3 signal of MUX is high level, selects adopting for Article 3 LED branch roads
The ohmically sampled voltage of sample is input to the inverting input of error amplifier, and the setting with error amplifier in-phase input end is joined
Examine voltage Vref to be compared, the error signal after amplification is subsequently inputted into the inverting input of comparator, with comparator
The sawtooth signal Vsaw that in-phase input end is set is compared, and produces the work that feedback control signal carrys out control voltage adjuster
Make, Bn is comparator output terminal signal in figure three, for the work of control voltage adjuster.
Embodiments of the invention are that sampling resistor R1, R2, R3 value are 1 Ω, the model LA_W57B_ of LED
TYP, the model IRF740 of each LED branch road metal-oxide-semiconductor, the model ADG528F of MUX, the type of error amplifier
Number it is OPA340, the scope of the reference voltage Vref of error amplifier in-phase input end is 0.2~0.35V, the model of comparator
For LM319, comparator inverting input sawtooth waveforms Vsaw amplitude is 5V, the model 74LS74A of d type flip flop, d type flip flop
Clock signal clk is that dutycycle is 1/3rd, and frequency is 66000Hz impulse wave, two inputs and the model 74HC08 of door.
The present invention is that the metal-oxide-semiconductor timesharing conducting of each LED branch road is controlled using pulse unit, controls MUX
Timesharing selects the sampled voltage on each LED branch road sampling resistor to be input in feedback control unit, thus a plurality of LED branch roads
The same feedback control unit of time-sharing multiplex, reduce the number for realizing that LED flows required current regulator elements in circuit, profit
With same error amplifier, each LED branch current is realized, the uniformity of voltage, simplifies circuit structure, reduce circuit damage
Consumption.MUX, error amplifier and comparator are sequentially connected in series to form feedback control unit to control each LED branch road
Electric current, first, second and third is controlled using the reference voltage Vref of error amplifier and sampling resistor R1, R2, R3 ratio
The electric current of LED branch roads, the reference voltage of error amplifier can accomplish 0.2V or so, reduce and realize that each LED branch road is equal
The pressure drop on current regulator needed for stream, reduces circuit loss.Circuit disclosed in this invention can be set by pulse unit
LED branch roads are expanded to more than three by meter and the selection of MUX model, are adapted to high-power, multi-string LED application.
Claims (6)
1. a kind of multipath LED constant current drive circuit, including voltage regulator, LED channel array and feedback control unit, its feature
It is, the output end of the voltage regulator is connected with first input port of LED channel array, and the of LED channel array
Two input ports are connected with first output port of pulse unit, the output end and feedback control unit of LED channel array
First input port be connected, second input port of feedback control unit and second output port phase of pulse unit
Even, the output end of feedback control unit is connected with the input of voltage regulator；Wherein,
Described voltage regulator, voltage-regulation is adjusted for receiving feedback control signal, and according to the feedback control signal
The output voltage of device；
Described LED channel array includes three LED branch roads, and each LED branch roads include the LED of at least two series connection, and described three
It is connected after bar LED branch circuit parallel connections with the output end of voltage regulator；Every LED branch road include a metal-oxide-semiconductor, a LED string,
One sampling resistor, described metal-oxide-semiconductor, LED string, sampling resistor are in parallel with electric capacity after being sequentially connected in series, in three LED branch roads
Sampling resistor resistance is identical；
First input port of described feedback control unit is connected to the output end of LED channel array, feedback control unit
Second input port be connected to second output port of pulse unit, the output end of feedback control unit is connected to voltage
The input of adjuster；Described feedback control unit includes a MUX, an error amplifier and a comparison
Device, described MUX, an error amplifier and a comparator are sequentially connected in series, for producing feedback control
Signal control voltage adjuster work processed；
Described pulse unit includes one two input and gate circuit, three d type flip flops, described one two input and door electricity
Road, three d type flip flops are sequentially connected, for producing pulse signal control LED channel array and feedback control unit work.
A kind of 2. multipath LED constant current drive circuit according to claim 1, it is characterised in that described voltage regulator
Booster type voltage regulator or voltage-dropping type voltage regulator can be used.
A kind of 3. multipath LED constant current drive circuit according to claim 1, it is characterised in that described LED channel array
It is after a metal-oxide-semiconductor, a LED string, a sampling resistor in every branch road are sequentially connected in series and electric including three LED branch roads
It is as follows to hold structure in parallel：
The metal-oxide-semiconductor M in first LED branch road in three LED branch roads1Source electrode be connected to the defeated of the voltage regulator
Go out end, grid is connected to first output end of pulse unit, and drain electrode is connected respectively to the LED string in first LED branch road
A port, electric capacity C1A port, electric capacity C1Second port ground connection, second port of LED string is with adopting
Sample resistance R1A port be connected, second port of sampling resistor ground connection, LED string is connected with sampling resistor, sampling
Resistance R1A port export first article of LED branch road sampled voltage；
Article 2 LED branch road metal-oxide-semiconductors M in three LED branch roads2Source electrode be connected to the output end of the voltage regulator,
Grid is connected to second output end of pulse unit, and drain electrode is connected respectively to first of the LED string in Article 2 LED branch roads
Individual port, electric capacity C2A port, electric capacity C2Second port ground connection, second port of LED string and sampling resistor
R2A port be connected, second port of sampling resistor ground connection, LED string is connected with sampling resistor, sampling resistor R2's
A port exports the sampled voltage of Article 2 LED branch roads；
Article 3 LED branch road metal-oxide-semiconductors M in three LED branch roads3Source electrode be connected to the output end of the voltage regulator,
Grid is connected to the 3rd output end of pulse unit, and drain electrode is connected respectively to first of the LED string in Article 3 LED branch roads
Individual port, electric capacity C3A port, electric capacity C3Second port ground connection, second port of LED string and sampling resistor
R3A port be connected, second port of sampling resistor ground connection, LED string is connected with sampling resistor, sampling resistor R3's
A port exports the sampled voltage of Article 3 LED branch roads.
4. a kind of multipath LED constant current drive circuit according to claim 1, it is characterised in that described pulse unit
First output port is connected to the grid of first LED branch road metal-oxide-semiconductor, for controlling first LED branch road；Described pulse
Second output port of unit is connected to the grid of Article 2 LED branch road metal-oxide-semiconductors, for controlling Article 2 LED branch roads；It is described
The 3rd output port of pulse unit be connected to the grids of Article 3 LED branch road metal-oxide-semiconductors, for controlling Article 3 LED branch
Road.
A kind of 5. multipath LED constant current drive circuit according to claim 1, it is characterised in that described feedback control list
The structure that a MUX in member, an error amplifier and a comparator are sequentially connected in series is as follows：
First input port A of described MUX1First output port of pulse unit is connected to, for selecting
Export the sampled voltage of first LED branch road；Second input port A of described MUX2It is connected to pulse unit
Second output port, for select output Article 2 LED branch roads sampled voltage；The 3rd of described MUX
Input port A3The 3rd output port of pulse unit is connected to, for selecting the sampled voltage of output Article 3 LED branch roads；
4th input port S of described MUX2It is connected to first LED branch road sampling resistors R1A port, institute
5th input port S of the MUX stated3It is connected to Article 2 LED branch road sampling resistors R2A port, it is described
MUX the 6th input port S5It is connected to Article 3 LED branch road sampling resistors R3A port；
The inverting input of the error amplifier is connected to the output end of MUX, the in-phase input end of error amplifier
It is connected to reference voltage；
The in-phase input end of the comparator is connected to the output end of error amplifier, and the inverting input of comparator is connected to tiltedly
Slope generator.
6. a kind of multipath LED constant current drive circuit according to claim 1, it is characterised in that in the pulse unit
One two input and gate circuit, the structure that three d type flip flops are sequentially connected is as follows, first output end of first d type flip flop
Mouth Q1 is connected to first input port D2 of second d type flip flop, first output port Q2 connection of second d type flip flop
To first input port D3 of the 3rd d type flip flop, second output port of first d type flip flopIt is defeated to be connected to two
Enter first input port with door, second output port of second d type flip flopIt is connected to the second of two inputs and door
Individual input port, two inputs and the output end of door are connected to first input port D1 of first d type flip flop, and first D is touched
Send out second input port clk1, the second input port clk2 of second d type flip flop of device, the of the 3rd d type flip flop
Two input port clk3 are connected to clock generation circuit.
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| CN201610367582.6A CN105934029B (en) | 2016-05-30 | 2016-05-30 | A kind of multipath LED constant current drive circuit |
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| CN107659149B (en) * | 2016-12-08 | 2023-08-29 | 深圳市华芯邦科技有限公司 | Hybrid DC power conversion device and method |
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| CN107635313B (en) * | 2017-10-19 | 2019-08-27 | 河北科技大学 | It is a kind of that the Multi-path LED driver of light modulation is realized from stream based on capacitor |
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| CN111918451A (en) * | 2020-08-11 | 2020-11-10 | 英麦科（厦门）微电子科技有限公司 | Multi-path LED active drive matching circuit |
| CN112788817B (en) * | 2021-02-19 | 2024-02-23 | 杭州优特电源有限公司 | Multi-output LED driving power supply and control circuit thereof |
| CN113056053B (en) * | 2021-02-19 | 2024-02-27 | 杭州优特电源有限公司 | Dual-channel cold-warm color temperature LED control circuit |
| CN114153259B (en) * | 2021-11-29 | 2023-05-26 | 苏州洪芯集成电路有限公司 | Multichannel constant current source voltage regulating circuit and control method thereof |
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