CN204929321U - LED drive circuit of multichannel independent control - Google Patents
LED drive circuit of multichannel independent control Download PDFInfo
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- CN204929321U CN204929321U CN201520493998.3U CN201520493998U CN204929321U CN 204929321 U CN204929321 U CN 204929321U CN 201520493998 U CN201520493998 U CN 201520493998U CN 204929321 U CN204929321 U CN 204929321U
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Abstract
The utility model discloses a LED drive circuit of multichannel independent control, constant -current drive circuit and a plurality of LED branch road including all LED sharing, LED branch road series connection is in the constant current circuit output, wherein the LED branch road include at least one LED lamp cluster and corresponding to that LED lamp cluster sets up and can work at short circuit, the bypass circuit of opening a way, the bypass circuit is connected with the positive negative pole of LED lamp, controls the going out, light of LED lamp of institute's connection branch road under short circuit, the circumstances of opening a way respectively. The control end of bypass circuit is connected to the programmable chip, can carry out the isolation control respectively to each LED lamp cluster of the series connection under the constant current drive power supply independently.
Description
Technical field
The utility model relates to LED general illumination field, specifically refers to the LED drive circuit that a kind of multichannel independently controls.
Background technology
LED is widely used in general lighting, simultaneously also the frequent mode being linked to be lamp string with color lamp to show various dynamic effect as view, stage, red-letter day and advertising lighting light source, by simply connecting and controlling to embody flicker and flowing water two kinds of dynamic effects, whole piece lamp string can be divided into less several roads to be together in parallel controlling respectively, each shunt seals in certain current-limiting resistance can directly by constant voltage source load, even if each is independent along separate routes is also feasible by a constant-current supply driving, driving design is also comparatively simple.So this lamp string is more universal, also horse race lamp is commonly called as, but owing to only having little several shunt to light the effect extinguished and form flicker flowing water in turn, the style of this horse race lamp is less, periodically also very strong, thus manifestation mode is stereotyped more dull, thus causes the attracts attention time of short duration, is difficult to the dynamic effect embodying rich and variedization.
In order to overcome the effect of this periodicity and dullness, need lamp string to have more lamp pearl and multiple or many cluster of lamps, ornamental pearl are independently controlled, for controlling complicated professional light of stage on a large scale, current employing DMX512 agreement, control signal is sent to each LED light source by control desk, and the driver of each LED light source must be equipped with the chip of this Signal reception corresponding and decoding function, then through being converted to control signal.And in a lot of occasion, as external wall of building lamp decoration, set up a platform temporarily, spare time culture performance, outdoor scene and the aspect such as advertisement and festive air enhancing, the style that needs to change irregularly relatively abundant and high-power color lamp reach enough strong rendering effect, this professional light of stage seem more complicated, the time-consuming and high cost of dismounting is installed, therefore application is restricted.
If adopt single power supply and design con-trol circuit has enough output ports, then can simply the parallel connection of different lamp pearl be linked in DC constant voltage power supply, just can carry out independent control to them easily, but for powerful lamp pearl, the electric current that lamp pearl as 3W passes through is at about 700 ~ 800mA, the pressure drop of each lamp pearl is at 2V(red-light LED) to 3 ~ 3.5V(blue-ray LED), take the mode of multi-channel parallel, and in order to obtain colourful change and dynamic effect, should adopt that quantity is as much as possible independently to be controlled along separate routes, as 20 tunnels just need DC power supply to provide about 15A operating current, the increase of the difficulty that big current brings device to select for Power Management Design and cost, low pressure more causes the very large reduction of rectification efficiency.
Certainly, the series connection of multiple low-power LED or series connection integration packaging (COB) lamp pearl can be adopted in each parallel branches to improve operating voltage to reduce electric current, but this method is also difficult to solve completely the problem that parallel connection brings, unlike the lamp pearl of single-chip package, points of proximity light source is convenient to optically focused design simultaneously, each LED different components voltage-current characteristic is also not quite identical, the electric current being difficult to ensure to pass through on every road under the connected mode of parallel connection is all identical, because residing radiating condition is different, the inconsistent of aging and out-of-service time also can be caused.For ensureing reliability and working life, generally need to carry out constant current driving to LED, so the mode that multiple LED lamp bead is more suitable for connecting is connected with constant-current drive circuit, otherwise drive circuit can only carry out current constant control to total current, the current constant of each shunt in parallel cannot be ensured, or each LED lamp bead adopts constant-current driving power supply separately, cause redundancy and the complex structure of circuit, cause reliability to reduce.
Even if adopt constant current to drive for parallel connection LED lamp group, be also difficult to ensure that the electric current of each shunt distributes identical, can only total current be controlled constant, and control then more difficult for the separation of lamp pearl different in single channel series circuit.
Utility model content
The utility model is intended to solve one of technical problem in correlation technique at least to a certain extent.For this reason, an object of the present utility model is to propose the LED drive circuit that a kind of multichannel independently controls, and independently can control, and circuit structure is simple to the LED string of the series connection under constant-current driving power supply.
For achieving the above object, the utility model one side embodiment proposes the LED drive circuit that a kind of multichannel independently controls, the LED drive circuit that described multichannel independently controls comprises constant-current source circuit and LED branch road, described LED branch road is connected in series in described constant-current circuit output, wherein said LED branch road comprises at least one LED string and corresponds to bypass circuit that is that described LED string is arranged and that can be operated between short circuit, open-circuit condition, described bypass circuit is connected with LED, and the control end of described bypass circuit is connected to programmable chip.
According to the LED drive circuit that the multichannel of the utility model embodiment proposition independently controls, LED string is being connected in constant-current circuit, carry out constant current driving, the electric current flowing through LED is substantially identical, aging and out-of-service time relatively, reliability is high, overall use cost is low, bypass circuit can be between short circuit, open-circuit working state, realize controlling the separation of LED, carry out the open circuit of programming Control bypass circuit or short circuit conversion by programming chip, can realize the bright of LED or the effect of shadow controlling to convert out various style respectively that goes out.
According to the utility model embodiment, described bypass circuit comprises the first bypass circuit, described first bypass circuit comprises PNP transistor Q1, NPN transistor Q2, resistance RB and optocoupler OC1, the base stage of wherein said PNP transistor Q1 is connected with the collector electrode of described NPN transistor Q2, the collector electrode of described PNP transistor Q1 is connected with the base stage of described NPN transistor Q2 by the output electrode of described optocoupler OC1, described resistance RB is connected to the emitter of described PNP transistor Q1 between collector electrode, the emitter of described PNP transistor Q1 is connected to the anode of described LED, it is negative electrode that the emitter of described NPN transistor Q2 is connected to described LED, the input of described optocoupler OC1 is as the control end of described bypass circuit.
Further, described bypass circuit also comprises the second bypass circuit, described second bypass circuit comprises MOS transistor Q3, resistance R4, electric capacity C2, diode D2 and optocoupler OC2, the source electrode of wherein said MOS transistor Q3 is connected to the negative electrode of described LED, the drain electrode of described MOS transistor Q3 is connected to the anode of described LED, the grid of described MOS transistor Q3 is connected to the output electrode of described optocoupler OC2, one end of described resistance R4, the input of described optocoupler OC2 is as the control end of described bypass circuit, the other end of described resistance R4 is connected with the negative electrode of diode D2, the anode of diode is connected to the anode of a LED, described electric capacity C2 one end is connected to the other end of described resistance R4, the other end of described electric capacity C2 is connected to the drain electrode of described MOS transistor, one end of described resistance R4 is also connected to the drain electrode of described MOS transistor by the output electrode of described optocoupler OC2.
According to a specific embodiment of the present utility model, described first bypass circuit is as the bypass circuit of first order LED, and described second bypass circuit is as the second level and with the bypass circuit of the LED of subordinate.
According to a specific embodiment of the present utility model, described constant-current circuit comprises JK flip-flop, comparator CM, not gate NOT, with door AND, MOS transistor Q4, resistance RS, resistance R1 and resistance R2, wherein resistance R1 and resistance R2 is connected between operating voltage input and ground after connecting, between described resistance R1 and resistance R2, there is first node, the negative input end of the CM of described comparator is connected to described first node, between the source electrode that described resistance RS is connected to described MOS transistor Q4 and ground, the positive input terminal of described comparator CM is connected to the source electrode of described MOS transistor Q4, the output of described comparator is connected to the input of described not gate NOT, one end of resistance R3, the output of described not gate NOT is connected to an input that is described and door AND, the described grid being connected to described MOS transistor Q4 with the output of door AND, the drain electrode of described MOS transistor Q4 is connected to described DC power supply terminal, the other end of described resistance R3 is connected to the R port of JK flip-flop, J port and the K port of described JK flip-flop are connected to working power input, the S port ground connection of described JK flip-flop, the Q port of described JK flip-flop is connected to the second input that is described and door AND, described JK flip-flop receives the clock pulse signal of programmable chip.
According to a specific embodiment of the present utility model, the LED drive circuit that multichannel independently controls also comprises branch road power supply, described DC power supply comprises DC supply input Vin, inductance L, electric capacity C1 and diode D1, one end of described inductance L is connected with the anode of described diode and described constant-current circuit respectively, the other end of described sense L is connected with one end of described electric capacity C1 and one end of described LED branch road respectively, the other end of described electric capacity C1 is connected with input supply terminal Vin respectively, the negative electrode of described diode is connected with described power end Vin, described power end Vin also connects the other end of described LED branch road.
In the LED drive circuit that the multichannel that the utility model provides independently controls, multiple LED is connected with constant-current drive circuit in a series arrangement, such output current is exactly single-string LED operating current, current constant control can be carried out to whole string LED, by going here and there a LED two ends partial flow bypass path circuit in parallel to each or each point needing to control, below the conducting voltage reducing the voltage to this LED during bypass circuit conducting, such electric current all passes through from bypass, the extinguishing of the single or part lamp pearl in series circuit can be controlled by the mode of this short circuit, execution mode and effect can be understood by the following specific embodiments further more specifically.
Accompanying drawing explanation
Fig. 1 is the circuit theory connection layout according to the utility model embodiment;
Fig. 2 is the first the bypass circuit structure chart according to the utility model embodiment;
Fig. 3 is the second bypass circuit structure chart according to the utility model embodiment;
Fig. 4 is the complete circuit be combined with the second bypass circuit according to the first bypass circuit of the utility model embodiment;
The oscillogram of Fig. 5 the utility model under peak value current constant control, wherein, (a) is current waveform during whole loaded work piece; B () is oscillogram when average current increases when making loaded pressure drop or impedance reduce due to bypass short circuit; C () keeps the oscillogram after average current substantially constant by modulation switch circuit work frequency.
Embodiment
Be described below in detail embodiment of the present utility model, the example of described embodiment is shown in the drawings, and wherein same or similar label represents same or similar element or has element that is identical or similar functions from start to finish.Be exemplary below by the embodiment be described with reference to the drawings, be intended to for explaining the utility model, and can not be interpreted as restriction of the present utility model.
Below with reference to the accompanying drawings the LED drive circuit that the multichannel describing the proposition of the utility model embodiment independently controls, as shown in Figure 1, the LED drive circuit that a kind of multichannel independently controls, comprise direct-current input power supplying 1, constant-current source circuit 2 and LED branch road, described LED branch road is connected in series in the output of described constant-current circuit 2, wherein said LED branch road comprises at least one LED string 5 and corresponds to that described LED string is arranged and can be operated in short circuit, bypass circuit 3(4 between open-circuit condition), one end 32 of described bypass circuit, 42 are connected with the anode of LED, the other end 33(43 of described bypass circuit) be connected with the negative electrode of LED, the control end 31 of described bypass circuit, 41 are connected to programmable chip.
The circuit diagram of the first bypass circuit as shown in Figure 2, described first bypass circuit comprises PNP transistor Q1, NPN transistor Q2, resistance Rb and optocoupler OC1, the base stage of wherein said PNP transistor Q1 is connected with the collector electrode of described NPN transistor Q2, the collector electrode of described PNP transistor Q1 is connected with the base stage of described NPN transistor Q2 by the output electrode of described optocoupler OC1, described resistance Rb is connected to the emitter of described PNP transistor Q1 between collector electrode, the emitter of described PNP transistor Q1 is connected to the anode of described LED as one end 32 of bypass circuit, it is negative electrode that the emitter of described NPN transistor Q2 is connected to described LED as the other end 33 of described bypass circuit, the input of described optocoupler OC1 is as the control end 31 of described bypass circuit.
The circuit diagram of the second bypass circuit as shown in Figure 3, described second bypass circuit comprises MOS transistor Q3, resistance R4, electric capacity C2, diode D2 and optocoupler OC2, the source electrode of wherein said MOS transistor Q3 is connected to the negative electrode of described LED as the other end of described bypass circuit, the drain electrode of described MOS transistor Q3 is connected to the anode of described LED as one end of described bypass circuit, the grid of described MOS transistor Q3 is connected to the output electrode of described optocoupler OC2, one end of described resistance R4, the input of described optocoupler OC2 is as the control end of described bypass circuit, the other end of described resistance R4 is connected with the negative electrode of diode D2, the anode of diode is connected to the anode of a LED, described electric capacity C2 one end is connected to the other end of described resistance R4, the other end of described electric capacity C2 is connected to the drain electrode of described MOS transistor, one end of described resistance R4 is also connected to the drain electrode of described MOS transistor by the output electrode of described optocoupler OC2.
As shown in Figure 1 and Figure 4, described first bypass circuit 3 is as the bypass circuit of first order LED, and described second bypass circuit 4 is as the second level and with the bypass circuit of the LED of subordinate.
As shown in Figure 4, constant-current circuit comprises JK flip-flop, comparator CM, not gate NOT, with door AND, MOS transistor Q4, resistance RS, resistance R1 and resistance R2, wherein resistance R1 and resistance R2 is connected between operating voltage input and ground after connecting, between described resistance R1 and resistance R2, there is first node, the negative input end of the CM of described comparator is connected to described first node, between the source electrode that described resistance RS is connected to described MOS transistor Q4 and ground, the positive input terminal of described comparator CM is connected to the source electrode of described MOS transistor Q4, the output of described comparator is connected to the input of described not gate NOT, one end of resistance R3, the output of described not gate NOT is connected to an input that is described and door AND, the described grid being connected to described MOS transistor Q4 with the output of door AND, the drain electrode of described MOS transistor Q4 is connected to described DC power supply terminal, the other end of described resistance R3 is connected to the R port of JK flip-flop, J port and the K port of described JK flip-flop are connected to working power input, the S port ground connection of described JK flip-flop, the Q port of described JK flip-flop is connected to the second input that is described and door AND, described JK flip-flop receives the clock pulse signal of programmable chip.
As shown in Figure 4, DC power supply comprises DC supply input Vin, inductance L, electric capacity C1 and diode D1, one end of described inductance L is connected with the anode of described diode and described constant-current circuit respectively, the other end of described sense L is connected with one end of described electric capacity C1 and one end of described LED branch road respectively, the other end of described electric capacity C1 is connected with input supply terminal Vin respectively, the negative electrode of described diode is connected with described power end Vin, and described power end Vin also connects the other end of described LED branch road.
In embodiment of the present utility model, LED string 5 can be single led lamp, also can also be the LED of multiple series connection, LED can be single lamp pearl, also can be multiple series lamp pearl.
The LED drive circuit that multichannel as shown in Figure 5 independently controls, high direct voltage Vin after 220V electric main input rectifying is at about 300V, constant-current control circuit operating voltage Vcc is generally at 10 ~ 15V, the voltage fed back by current sampling resistor Rs to be compared with reference voltage Vref at comparator CM and limits driving peak current, comparator exports and controls power MOS transistor Q4 by not gate NOT with door AND, by JK flip-flop make within a clock cycle to the pwm pulse of MOS transistor Q4 can only saltus step once to ensure steady operation, the operating frequency of MOS transistor Q4 switch just depends on outside input recurrent pulse CP.LED branch road and inductance L are concatenated between positive source bus and MOS transistor Q4 drain, in parallel with sustained diode, make inductance when metal-oxide-semiconductor turns off by energy that LED load release stores.The impedance operator of LED can be similar to be regarded a constant voltage supported V 0 as and adds a pure resistance R0, if the restriction peak value of comparator to electric current is Im, opens determined by following two equations respectively with the change of blocking interval current i t in time at MOS transistor Q4,
During Q4 conducting (i<Im):
Ldi/dt+iR0+V0=Vin,i=(Vin–V0)/R0[1–exp(-R0t/L)]（1）
When Q4 turns off (i>Im):
-Ldi/dt+iR0+V0=0,i=Imexp(-R0t/L)–[1–exp(-R0t/L)]V0/R0（2）
When power input voltage Vin change within the specific limits or loaded pressure drop and impedance variation little time current i change very little, namely output current can reach less input voltage rate of change and loading rate, namely constant current drive.
In first bypass circuit, PNP transistor Q1 and NPN transistor Q2 conducting under optocoupler OC1 isolated controlling, LED1 both end voltage can be dropped to 1 ~ 1.2V makes LED1 extinguish, and PNP transistor Q1 and NPN transistor Q2 still relies on the positive feedback of this structure can maintain himself conducting state, optocoupler is without then transistor cutoff during input, LED recovers to light, the bypass that each LED two ends parallel connection one is such on whole series circuit, just can realize controlling the independence of all lamp pearls, maintain the constant current output of drive circuit simultaneously, the control signal of light-coupled isolation transmission comprises single-chip microcomputer by programmable chip, the port of FPGA or ARM chip provides, can according to the independent number of active lanes controlled, the demand of signal transacting and dynamic effect design is selected.
The first bypass circuit can be considered equivalent silicon controlled by-pass unit, and its conducting voltage, higher than 1V, can realize the object that the utility model reaches, but during conducting, the larger efficiency of electrical piano power loss is lower.By the second bypass circuit, achieve the conducting of low-resistance and low pressure drop and can conducting state be maintained, the feature of MOS transistor Q3 voltage control and grid capacitance stored charge thereof is utilized to maintain the constant conduction of metal-oxide-semiconductor, because single led pressure drop is lower, the upper lamp pearl LED1 confession of the grid to MOS transistor Q3 being electrically connected to LED string controls as headlight pearl LED2, if a lamp pearl comprises the LED of two or more series connection, only need be connected to when headlight pearl upper end, there is provided the voltage of about 2.8V that it then can be made to reach low-resistance conducting state to pressure common MOS transistor Q3.
In the present embodiment, when the output MOS transistor Q3 of optocoupler OC2 ends, the pressure drop of LED1 and LED2 is charged to electric capacity C2, after diode D2 can prevent MOS transistor Q3 conducting, electric capacity C2 discharges again, apply forward grid voltage through resistance R4 to MOS transistor Q3 again to make it conducting and have the regular hour to postpone, thus make electric capacity C2 can be filled electric energy to provide the abundant conducting of sufficiently high voltage guarantee MOS transistor Q3 to grid.LED2 can be made like this to extinguish, and conduction voltage drop can reach about the 0.1V of low-power consumption, when optocoupler OC2 input end is in high level, its output makes MOS transistor Q3 end by drop-down for the grid of MOS transistor Q3, and LED2 lights.LED1 all has the bypass structure the same with LED2 with other lamp pearl, the LED1 lamp pearl bypass topmost connected with power source bus then can adopt the first bypass path, without the need to cross-over connection, although power loss is a little large, but only used this unit, the mode that other lamp pearl then all adopts MOS transistor Q3 to jump to upper level obtains sufficiently high grid voltage.Light with the change procedure extinguished on whole cluster of lamps, ornamental pearl, if when certain lamp pearl by-pass unit is in conducting low pressure drop, just can not provide voltage for next stage metal-oxide-semiconductor grid, in order to avoid this situation, can before each control cycle, make all LED lamp bead bypasses all short time cut-offs, within this short time, LED electrical voltage rise is not lit to close to operational voltage value, control from lower to upper successively light or extinguish, this mode can realize control chip programming again.
In the present embodiment, the LED drive circuit that multichannel independently controls has the feedback system adopting peak current sampling, by the bypass short circuit control method of series LED lamp string in constant-current drive circuit, not only can realize constant current to drive but also independently can control each lamp pearl and light and extinguishing, but from being all illuminated to the different conditions only having a lamp pearl to light, the loaded pressure drop of drive circuit and resistance difference are very large, if adopt peak current sample mode, be difficult to when load impedance wide variation ensure that average current is constant.According to (1) and (2) formula in above Current calculation result, the current waveform of different loads pressure drop and impedance can be drawn, as 16 LED lamp bead are lighted and 4 current waveforms lighted, respectively as shown in (a) and (b) in Fig. 5, although their peak current is controlled in steady state value, in fact their average current differs greatly, and does not therefore reach constant current and drives.Simultaneously, when a low loaded pressure drop that bright light pearl number is less and impedance, between the afterflow period that MOS transistor Q4 turns off, electric current declines slack-off, when next cycle arrives, electric current does not also drop to 0, inductance L just can not discharge energy storage completely, the magnetic saturation of inductance core will be caused like this, but by assisting pulse width modulation (PWM) in the mode of pulse frequency modulated (PFM), just can ensure average current substantial constant.From Fig. 5 (b) when only having 4 lamp pearls to light, after switching circuit operating frequency drops to 31kHz by 80kHz, average current can keep substantially identical, during other difference bright light pearl number, by clock pulse modulation to the corresponding operating frequency keeping current constant, if the input clock pulse of JK flip-flop is also provided by control chip in Fig. 4, lamp pearl number of lights object statistics and operating frequency adjustment just all can drive in the constant current of control chip programming realization, and waveform as shown in Figure 5 (c).
In description of the present utility model, it is to be appreciated that term " first ", " second " only for describing object, and can not be interpreted as instruction or hint relative importance or the implicit quantity indicating indicated technical characteristic.Thus, be limited with " first ", the feature of " second " can express or impliedly comprise at least one this feature.In description of the present utility model, the implication of " multiple " is at least two, such as two, three etc., unless otherwise expressly limited specifically.
In the utility model, unless otherwise clearly defined and limited, the term such as term " installation ", " being connected ", " connection ", " fixing " should be interpreted broadly, and such as, can be fixedly connected with, also can be removably connect, or integral; Can be mechanical connection, also can be electrical connection; Can be directly be connected, also indirectly can be connected by intermediary, can be the connection of two element internals or the interaction relationship of two elements, unless otherwise clear and definite restriction.For the ordinary skill in the art, the concrete meaning of above-mentioned term in the utility model can be understood as the case may be.
In the description of this specification, specific features, structure, material or feature that the description of reference term " embodiment ", " some embodiments ", " example ", " concrete example " or " some examples " etc. means to describe in conjunction with this embodiment or example are contained at least one embodiment of the present utility model or example.In this manual, to the schematic representation of above-mentioned term not must for be identical embodiment or example.And the specific features of description, structure, material or feature can combine in one or more embodiment in office or example in an appropriate manner.In addition, when not conflicting, the feature of the different embodiment described in this specification or example and different embodiment or example can carry out combining and combining by those skilled in the art.
Although illustrate and described embodiment of the present utility model above, be understandable that, above-described embodiment is exemplary, can not be interpreted as restriction of the present utility model, those of ordinary skill in the art can change above-described embodiment, revises, replace and modification in scope of the present utility model.
Claims (6)
1. the LED drive circuit that independently controls of a multichannel, it is characterized in that comprising constant-current source circuit and LED branch road, described LED branch road is connected in series in described constant-current circuit output, wherein said LED branch road comprises at least one LED string and corresponds to bypass circuit that is that described LED string is arranged and that can be operated between short circuit, open-circuit condition, described bypass circuit is connected with LED, and the control end of described bypass circuit is connected to programmable chip.
2. the LED drive circuit that independently controls of multichannel according to claim 1, it is characterized in that described bypass circuit comprises the first bypass circuit, described first bypass circuit comprises PNP transistor Q1, NPN transistor Q2, resistance RB and optocoupler OC1, the base stage of wherein said PNP transistor Q1 is connected with the collector electrode of described NPN transistor Q2, the collector electrode of described PNP transistor Q1 is connected with the base stage of described NPN transistor Q2 by the output electrode of described optocoupler OC1, described resistance RB is connected to the emitter of described PNP transistor Q1 between collector electrode, the emitter of described PNP transistor Q1 is connected to the anode of described LED, it is negative electrode that the emitter of described NPN transistor Q2 is connected to described LED, the input of described optocoupler OC1 is as the control end of described bypass circuit.
3. the LED drive circuit that independently controls of multichannel according to claim 2, it is characterized in that described bypass circuit also comprises the second bypass circuit, described second bypass circuit comprises MOS transistor Q3, resistance R4, electric capacity C2, diode D2 and optocoupler OC2, the source electrode of wherein said MOS transistor Q3 is connected to the negative electrode of described LED, the drain electrode of described MOS transistor Q3 is connected to the anode of described LED, the grid of described MOS transistor Q3 is connected to the output electrode of described optocoupler OC2, one end of described resistance R4, the input of described optocoupler OC2 is as the control end of described bypass circuit, the other end of described resistance R4 is connected with the negative electrode of described diode D2, the anode of described diode is connected to the anode of a LED, described electric capacity C2 one end is connected to the other end of described resistance R4, the other end of described electric capacity C2 is connected to the drain electrode of described MOS transistor, one end of described resistance R4 is also connected to the drain electrode of described MOS transistor by the output electrode of described optocoupler OC2.
4. the LED drive circuit that independently controls of multichannel according to claim 3, it is characterized in that the bypass circuit of described first bypass circuit as first order LED, described second bypass circuit is as the second level and with the bypass circuit of the LED of subordinate.
5. according to the LED drive circuit that the arbitrary described multichannel of claim 1-4 independently controls, it is characterized in that described constant-current circuit comprises JK flip-flop, comparator CM, not gate NOT, with door AND, MOS transistor Q4, resistance RS, resistance R1 and resistance R2, wherein resistance R1 and resistance R2 is connected between operating voltage input and ground after connecting, between described resistance R1 and resistance R2, there is first node, the negative input end of the CM of described comparator is connected to described first node, between the source electrode that described resistance RS is connected to described MOS transistor Q4 and ground, the positive input terminal of described comparator CM is connected to the source electrode of described MOS transistor Q4, the output of described comparator is connected to the input of described not gate NOT, one end of resistance R3, the output of described not gate NOT is connected to an input that is described and door AND, the described grid being connected to described MOS transistor Q4 with the output of door AND, the drain electrode of described MOS transistor Q4 is connected with DC power supply terminal, the other end of described resistance R3 is connected to the R port of JK flip-flop, J port and the K port of described JK flip-flop are connected to working power input, the S port ground connection of described JK flip-flop, the Q port of described JK flip-flop is connected to the second input that is described and door AND, described JK flip-flop receives the clock pulse signal of programmable chip.
6. the LED drive circuit that independently controls of multichannel according to claim 5, characterized by further comprising DC power supply, described DC power supply comprises DC supply input Vin, inductance L, electric capacity C1 and diode D1, one end of described inductance L is connected with the anode of described diode and described constant-current circuit respectively, the other end of described sense L is connected with one end of described electric capacity C1 and one end of described LED branch road respectively, the other end of described electric capacity C1 is connected with input supply terminal Vin respectively, the negative electrode of described diode is connected with described power end Vin, described power end Vin also connects the other end of described LED branch road.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN106230414A (en) * | 2016-08-29 | 2016-12-14 | 成都信息工程大学 | A kind of MOSFET/IGBT high-speed driving circuit based on linear optical coupling isolation |
| CN106332406A (en) * | 2015-07-10 | 2017-01-11 | 桂林电子科技大学 | LED driver circuit with multi-channel independent control |
| CN107682964A (en) * | 2017-10-24 | 2018-02-09 | 江门市丽都照明有限公司 | A kind of high-voltage LED lamp control circuit |
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2015
- 2015-07-10 CN CN201520493998.3U patent/CN204929321U/en not_active Expired - Fee Related
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN106332406A (en) * | 2015-07-10 | 2017-01-11 | 桂林电子科技大学 | LED driver circuit with multi-channel independent control |
| CN106332406B (en) * | 2015-07-10 | 2020-04-10 | 桂林电子科技大学 | LED drive circuit of multichannel independent control |
| CN106230414A (en) * | 2016-08-29 | 2016-12-14 | 成都信息工程大学 | A kind of MOSFET/IGBT high-speed driving circuit based on linear optical coupling isolation |
| CN107682964A (en) * | 2017-10-24 | 2018-02-09 | 江门市丽都照明有限公司 | A kind of high-voltage LED lamp control circuit |
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