CN104661403A - LED driving circuit - Google Patents
LED driving circuit Download PDFInfo
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- CN104661403A CN104661403A CN201410825654.8A CN201410825654A CN104661403A CN 104661403 A CN104661403 A CN 104661403A CN 201410825654 A CN201410825654 A CN 201410825654A CN 104661403 A CN104661403 A CN 104661403A
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- led load
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- 230000006641 stabilisation Effects 0.000 claims abstract description 35
- 238000011105 stabilization Methods 0.000 claims abstract description 35
- 230000001105 regulatory effect Effects 0.000 claims description 15
- 230000001276 controlling effect Effects 0.000 claims description 8
- 239000003990 capacitor Substances 0.000 abstract 2
- 238000010586 diagram Methods 0.000 description 8
- 238000005516 engineering process Methods 0.000 description 2
- 230000033228 biological regulation Effects 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
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Abstract
The invention provides an LED driving circuit. The LED driving circuit comprises a voltage stabilization convertor, an output circuit and a controller, wherein the voltage stabilization convertor outputs constant voltage signals to the output circuit; the controller controls the current size of the output circuit; the output circuit comprises an LED load circuit, a current stabilization circuit and at least one capacitor element; the current stabilization circuit is connected with the LED load circuit in series; the at least one capacitor element is connected with the LED load circuit in parallel.
Description
Technical field
The present invention relates to a kind of LED circuit, especially a kind of LED drive circuit.
Background technology
Along with the fast development of LED, the power of LED is increasing, and gets more and more to the demand of light modulation and tune color.
Usual LED drive circuit is circuit composition as shown in Figure 1, comprises the regulated converter of the band circuit of power factor correction PFC that provides constant voltage to export, DC-to-DC DC-DC converter or linear power supply and carries out constant current control LED strip.The pulse width modulating signal PWM that DC-DC converter or linear power supply can be produced by controller is to carry out light modulation.Controller in drive circuit be all often digitized controller as single-chip microcomputer, it produces pulse width modulating signal PWM than being easier to, and modulates duty ratio, is but not easy to control amplitude.
In addition, although PWM light modulation has its advantage, also there is the problems such as noise is large, stroboscopic.Along with the requirement of people to light quality is more and more higher, control more and more to pay attention to current amplitude.
Summary of the invention
The technical problem to be solved in the present invention is to provide a kind of LED drive circuit, controls the current amplitude of LED load.
For achieving the above object, the present invention adopts following technical scheme:
A kind of LED drive circuit, comprise regulated converter, output circuit, controller, described regulated converter exports constant voltage signal to described output circuit, described controller controls the size of current of described output circuit, it is characterized in that, described output circuit comprises LED load circuit, current stabilization circuit and at least one capacity cell, described current stabilization circuit and described LED load circuit connected in series, at least one capacity cell described and described LED load circuit in parallel.
Preferably, above-mentioned LED drive circuit comprises the output circuit of multiple parallel connection, and controller is connected with the current stabilization circuit of each output circuit.
Preferably, described controller generates control signal to carrying out Synchronization Control to the LED load circuit of multiple described output circuit.Control signal is the pwm signal of homophase.
Preferably, described controller generation control signal carries out asynchronous controlling to described multiple LED load circuit.Control signal is the pwm signal of out of phase.
Preferably, above-mentioned LED load circuit is the series circuit that multiple LED element is formed, and each described LED element is in parallel with a described capacity cell.
Preferably, the LED load circuit of multiple output circuit is made up of the LED strip that glow color is different respectively, because the glow color of the LED strip of each LED load circuit is different, can realize toning and control.
Preferably, above-mentioned regulated converter is the AC-DC converter of AC-to DC or the DC-DC converter of DC-to-DC.
Compared with existing drive circuit, LED drive circuit of the present invention, realize current amplitude by control capacitance discharge and recharge to control, make the current amplitude of LED load circuit can not be reduced to zero when light modulation, thus the stroboscopic caused during load current when avoiding similar PWM light modulation.
In addition, by the asynchronous controlling of controller to Multi-path LED load circuit or multiplex output circuit, avoid when control signal exports high level signal, the electric current superposition of each paths of LEDs load circuit is excessive, reduce the output requirement to front end regulated converter, thus reduce design difficulty and the cost of power supply.
According to below with reference to the accompanying drawing description of this invention, other targets of the present invention and effectiveness will become apparent, and reader can fully understand the present invention.
Accompanying drawing explanation
Fig. 1 is the schematic diagram of the drive circuit of prior art LED multiple-channel output;
Fig. 2 is the electrical block diagram of an embodiment of LED drive circuit of the present invention;
Fig. 3 a is current direction schematic diagram under the structure of output circuit and high level;
Fig. 3 b is current direction schematic diagram under the structure of output circuit and low level;
Fig. 4 is the electrical block diagram of the another embodiment of LED drive circuit of the present invention;
Fig. 5 is the oscillogram of LED drive circuit work;
Fig. 6 is the oscillogram of the multiple output circuit of asynchronous controlling of LED driver.
Embodiment
Hereafter describe specific embodiments of the invention with reference to graphic in detail by embodiment.
Fig. 2 is the electrical block diagram of an embodiment of LED drive circuit of the present invention.With reference to Fig. 2,
LED drive circuit, comprise regulated converter 21, output circuit 22, controller 23, regulated converter 21 exports constant voltage signal to described output circuit, controller 23 controls the size of current of output circuit 22, output circuit 22 comprises LED load circuit K1, current stabilization circuit 222 and at least one capacity cell C1, current stabilization circuit 222 is connected with LED load circuit K1, a capacity cell C1 is in parallel with described LED load circuit K1, in the present embodiment, have employed a capacity cell 223 and LED load circuit in parallel, also multiple capacity cell and LED load circuit in parallel can be adopted, as can adopt multiple capacity cell connect then with LED load circuit in parallel, LED load circuit K1 is made up of a LED element, and LED load circuit also can be contacted by plural LED element and be formed.In addition, except electric capacity and LED load circuit in parallel, each LED element in LED load circuit also can be in parallel with a capacity cell.Regulated converter 21 can be the AC-DC variator or the dc-dc that comprise power factor school circuit, exports constant voltage signal to output circuit.
Fig. 3 a-3b is structural representation and the current direction schematic diagram of output circuit
,with reference to Fig. 3 a-3b, output circuit 22 is by LED load circuit K1, capacity cell C1 and current stabilization circuit 222 formed, current stabilization circuit 222 in the present embodiment current stabilization circuit 222 is linear power supplies, current stabilization circuit is by comparator U1, and switch element Q1, resistance R1 and resistance R2 form, comparator can be computing discharger, and switch element 226 can be triode or MOS switching tube.The output of comparator U1 is connected with the first end A of switch element Q1, resistance R1 is connected between the second end B of a switch element Q1 and input IN2 of comparator, resistance R2 is connected between the second end B of switch element Q1 and ground, and the 3rd end C of switch element Q1 is connected with LED load circuit.If switch element is triode, first end A is base stage, and the second end B is emitter-base bandgap grading, and the 3rd end C is collector electrode; If switch element is MOS switching tube, first end A is grid, and the second end B is source electrode, and the 3rd end C is drain electrode.When controller 23 exports high potential to current stabilization circuit 222, current direction such as Fig. 3 a of output circuit is with shown in the dotted line of arrow, electric current flows through LED load circuit K1, and charge to capacity cell C1, current stabilization circuit enters linear condition and controls the electric current flow through simultaneously.When controller 23 exports electronegative potential (0 current potential) to current stabilization circuit 222, as shown in Figure 3 b, the switch element of current stabilization circuit will be closed, and now not have electric current to flow through current stabilization circuit, and capacity cell C1, by starting electric discharge, continues to power to LED load circuit K1.
The electrical block diagram of another embodiment of Fig. 4 LED drive circuit of the present invention.With reference to Fig. 4, LED drive circuit comprises regulated converter 21, controller 23, output circuit 42, wherein output circuit 42 is made up of the output circuit 22 in Fig. 2 embodiment of multiple parallel connection, and namely output circuit 42 comprises multiple LED load circuit K1-Kn, multiple current stabilization circuit 222
1-222
nand multiple capacity cell C1-Cn.Each road of output circuit 42 comprises LED load circuit, current stabilization circuit and at least one capacity cell, and current stabilization circuit is connected with LED load circuit connected in series, an above-mentioned LED load circuit and the parallel connection of at least one capacity cell.Controller 23 and multiple current stabilization circuit 222 in output circuit 42
1-222
nconnect, control the size of current of each output circuit in output circuit 42.The circuit of power factor correction of regulated converter 21 can be a flyback circuit of reversed excitation, or boost booster circuit.Controller 23 can be microprocessor (MCU) or digital signal processor (DSP).
Fig. 5 be output circuit work wave, with reference to Fig. 5, controller 23 output voltage control signal is pwm signal.When pwm signal is high level, the electric current of LED load circuit increases gradually, and when pwm signal is low level, current stabilization circuit quits work, and capacity cell discharges, and powers to LED load circuit, and the electric current of LED load circuit reduces gradually.Due to the power supply of capacity cell, when current stabilization circuit quits work, the electric current of LED load circuit is not reduced to zero, but reduces the final state of low current that keeps gradually until the next cycle of pwm signal.At pwm signal next cycle, the electric current of LED load circuit raises gradually under the control of the high level of PWM.
When drive circuit comprises output circuit 22 of multiple parallel connection, controller 23 can export identical control signal, as homophase pwm signal, to the current stabilization circuit in each output circuit, and by each current stabilization circuit, Synchronization Control is carried out to each LED load circuit, the electric current of the LED load circuit of multiple output circuit is consistent.Controller 23 also can output multi-channel out of phase pwm control signal give multiple output circuit, asynchronous controlling is carried out to the LED load circuit of multiple output circuit, to reduce the requirement of the output current value to A regulated converter.Fig. 6 is the oscillogram of the multiple output circuit of asynchronous controlling in LED drive circuit.Composition graphs 4 and Fig. 6, controller 23 exports the control voltage signal of out of phase to the multiple current stabilization circuits 222 in output circuit
1-222
n, the phase place of multiple LED load circuit K1-Kn electric current changes accordingly along with the change of control voltage signal.When 222
1control voltage signal when being high level, electric current flows through LED load circuit K1, and charges to capacity cell C1; When 222
1control voltage be electronegative potential, 222
2control voltage when being high potential, current stabilization circuit 222
1quit work, and current stabilization circuit 222
2start working, at this moment the electric current of LED load circuit K2 increases gradually, and capacity cell C2 also charges gradually, and now capacity cell C1 carries out discharging and powers to LED load circuit K1, and the electric current of K1 reduces gradually.By that analogy, when last current stabilization circuit 222
nwhen starting working, other current stabilization circuit all quits work, and the electric current except LED load circuit Kn starts to increase, other capacity cell C1 ..., C
n-1all discharge, and corresponding parallel connection LED load circuit is powered, LED load circuit K1-K
n-1electric current reduce gradually but be not reduced to zero, work under the state finally remaining on a low current, the LED load circuit realiration of controller 23 pairs of multiplex output circuits 22 asynchronous controlling.In asynchronous controlling, control signal can be the pwm signal of out of phase.The control signal exported due to controller 23 is out of phase high level, and the electric current avoiding multiplex output circuit 22 all reaches maximum in section at one time, thus decreases the requirement of the output voltage to front end regulated converter 21.
The large I of the electric current of LED load circuit K1-Kn is realized by the duty ratio of PWM, and LED load circuital current is approximately equal to LED maximum current × duty ratio, and the size of ripple current is determined by electric capacity C1-Cn.Under stable state, the waveform of electric current and voltage is as Fig. 6.The capacitance of the C1-Cn of electric capacity is by make decision:
C=(I*ts)/(2(Vmax-Vmin))，
Wherein, C: capacitance,
The electric current of I:LED load circuit,
Ts: output voltage is the time of high level,
Vmax:LED load circuit two ends ceiling voltage,
Vmin:LED load circuit two ends minimum voltage.
According to the above, the LED drive circuit meeting the preferred embodiment of the present invention can improve LED load circuital current amplitude with pwm signal, can homophase or non-homophase control.If the LED load circuit of each is made up of the LED strip that glow color is different respectively in multiple output circuit 22, namely LED load circuit K1 is made up of the LED sending same coloured light, and other LED load circuit is made up of the LED different with glow color in K1, toning can be realized like this and control.In addition, completed the amplitude regulation and control of LED load electric current by pwm signal, can effectively reduce noise and EMI, thus reduce design difficulty and the cost of power supply.
The above is only the preferred embodiment of the present invention; it should be pointed out that for those skilled in the art, under the prerequisite not departing from the technology of the present invention principle; can also make some improvement and distortion, these improve and distortion also should be considered as protection scope of the present invention.
Claims (10)
1. a LED drive circuit, comprise regulated converter, output circuit, controller, described regulated converter exports constant voltage signal to described output circuit, described controller controls the size of current of described output circuit, it is characterized in that, described output circuit comprises LED load circuit, current stabilization circuit and at least one capacity cell, described current stabilization circuit and described LED load circuit connected in series, at least one capacity cell described and described LED load circuit in parallel.
2. LED drive circuit according to claim 1, is characterized in that, described LED drive circuit comprises the described output circuit of multiple parallel connection, and described controller is connected with the current stabilization circuit of each output circuit.
3. LED drive circuit according to claim 2, is characterized in that, described controller generates the LED load circuit of control signal to multiple described output circuit and carries out Synchronization Control.
4. LED drive circuit according to claim 3, is characterized in that, described control signal is homophase pwm signal.
5. LED drive circuit according to claim 2, is characterized in that, described controller generates control signal and carries out asynchronous controlling to described multiple LED load circuit.
6. LED drive circuit according to claim 5, is characterized in that, described control signal is the pwm signal of out of phase.
7. LED drive circuit according to claim 2, is characterized in that, the LED load circuit of multiple described output circuit is made up of the LED strip that glow color is different respectively.
8. LED drive circuit according to claim 1, is characterized in that, described LED load circuit is the series circuit that multiple LED element is formed, and each described LED element is in parallel with a described capacity cell.
9. LED drive circuit according to claim 1, it is characterized in that, described current stabilization circuit comprises comparator, switch element, resistive element, the output of described comparator is connected with the first end (A) of switch element, and described resistive element is connected between an input (IN2) of described comparator and second end (B) of switch element, and the output of described controller is connected with another input (IN1) of described comparator.
10. according to the arbitrary LED drive circuit described in claim 1 to 9, it is characterized in that, described regulated converter is AC-DC converter or DC-DC converter.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410825654.8A CN104661403A (en) | 2014-12-28 | 2014-12-28 | LED driving circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410825654.8A CN104661403A (en) | 2014-12-28 | 2014-12-28 | LED driving circuit |
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| Publication Number | Publication Date |
|---|---|
| CN104661403A true CN104661403A (en) | 2015-05-27 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201410825654.8A Pending CN104661403A (en) | 2014-12-28 | 2014-12-28 | LED driving circuit |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110545607A (en) * | 2018-05-28 | 2019-12-06 | 立锜科技股份有限公司 | Power supply circuit capable of reducing current ripple and method for reducing current ripple |
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| JP4379829B1 (en) * | 2008-05-08 | 2009-12-09 | 株式会社光洋電子工業 | Light source driving method and light source driving device |
| CN101754541A (en) * | 2010-01-27 | 2010-06-23 | 英飞特电子（杭州）有限公司 | DC bus voltage following control circuit suitable for multi-path parallel LEDs |
| CN102548109A (en) * | 2010-12-30 | 2012-07-04 | 英飞特电子（杭州）有限公司 | Load driving device and system |
| CN102695341A (en) * | 2012-05-28 | 2012-09-26 | 矽力杰半导体技术(杭州)有限公司 | LED drive power supply applicable to electronic transformer |
| WO2013063770A1 (en) * | 2011-11-02 | 2013-05-10 | 深圳市讯宇创科技有限公司 | Switched dimming led drive circuit and led light group |
| CN103118453A (en) * | 2011-11-16 | 2013-05-22 | 金德奎 | Light emitting diode (LED) tandem driving control circuit based on microcontroller and programming method of microcontroller |
| CN203057635U (en) * | 2013-01-09 | 2013-07-10 | 四川创境科技有限公司 | Energy-saving multi-path adjustable LED street lamp constant-current driving power supply |
| CN204335078U (en) * | 2014-12-28 | 2015-05-13 | 欧普照明股份有限公司 | A kind of LED drive circuit |
-
2014
- 2014-12-28 CN CN201410825654.8A patent/CN104661403A/en active Pending
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4379829B1 (en) * | 2008-05-08 | 2009-12-09 | 株式会社光洋電子工業 | Light source driving method and light source driving device |
| CN101754541A (en) * | 2010-01-27 | 2010-06-23 | 英飞特电子（杭州）有限公司 | DC bus voltage following control circuit suitable for multi-path parallel LEDs |
| CN102548109A (en) * | 2010-12-30 | 2012-07-04 | 英飞特电子（杭州）有限公司 | Load driving device and system |
| WO2013063770A1 (en) * | 2011-11-02 | 2013-05-10 | 深圳市讯宇创科技有限公司 | Switched dimming led drive circuit and led light group |
| CN103118453A (en) * | 2011-11-16 | 2013-05-22 | 金德奎 | Light emitting diode (LED) tandem driving control circuit based on microcontroller and programming method of microcontroller |
| CN102695341A (en) * | 2012-05-28 | 2012-09-26 | 矽力杰半导体技术(杭州)有限公司 | LED drive power supply applicable to electronic transformer |
| CN203057635U (en) * | 2013-01-09 | 2013-07-10 | 四川创境科技有限公司 | Energy-saving multi-path adjustable LED street lamp constant-current driving power supply |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110545607A (en) * | 2018-05-28 | 2019-12-06 | 立锜科技股份有限公司 | Power supply circuit capable of reducing current ripple and method for reducing current ripple |
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Application publication date: 20150527 |
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