CN203761627U - LED constant current drive circuit - Google Patents
LED constant current drive circuit Download PDFInfo
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- CN203761627U CN203761627U CN201320866207.8U CN201320866207U CN203761627U CN 203761627 U CN203761627 U CN 203761627U CN 201320866207 U CN201320866207 U CN 201320866207U CN 203761627 U CN203761627 U CN 203761627U
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- current
- constant
- drive circuit
- constant current
- current control
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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
- Y02B20/40—Control techniques providing energy savings, e.g. smart controller or presence detection
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Abstract
An LED constant current drive circuit comprises an alternating current input grade, a transformer connected with a direct current output end of the alternating current input grade, and a constant current control circuit. The constant current control circuit is composed of a constant current control chip, a power tube, a current sampling resistor connected between a source electrode of the power tube and the ground, and a feedback loop used for detecting voltage of an secondary edge output end of the transformer. A grid electrode of the constant current control chip is connected with a grid electrode of the power tube. The source electrode of the power tube is connected with a current sampling end of the constant current control chip. An output end of the feedback loop is connected with a voltage sampling end of the constant current control chip. The constant current control chip also has a power factor correction pin which is connected with a common end of a first original edge and a second original edge. According to the LED constant current drive circuit, structure of an LED drive circuit is simplified, cost of LED drive is reduced, and size is reduced at the same time. With the adoption of the LED constant current drive circuit, LED products of isolated constant-current drive, high in power factor and efficiency, are achieved.
Description
Technical field
The utility model belongs to electronic circuit field, relates to a kind of LED constant-current drive circuit.
Background technology
Non-isolated DC/DC transducer in Switching Power Supply, press the relation between input voltage and output voltage, can be divided into buck (Buck) DC/DC transducer, boost type (Boost) DC/DC transducer, three kinds of Basic Topologicals of step-down/up type (Buck Boost) DC/DC transducer, this three basic structures is by inductance, one way conducting device and switching device composition, just three's annexation difference.
Use Switching Power Supply can utilize alternating current to power to LED, AC-powered LED illumination can reduce costs, but voltage ripple of power network can cause LED overcurrent to drive and affect its useful life, is important so LED is carried out to constant current driving in the occasion of Alternating Current Power Supply.
The object of power factor correction is that the waveform of the voltage and current of input is calibrated to the as far as possible consistent perfect condition of phase place, in the time that initial phase is consistent, phase changing capacity in same time is consistent and can obtains high power factor.
In conventional LED drive circuit, be applied to the power factor correction part of LED drive circuit, then coordinate other power supply chips to build overall drive circuit.Sort circuit complicated structure, the LED that makes finished product has that volume is large, processed complex, high in cost of production shortcoming.
Utility model content
For overcoming the circuit structure complexity of existing LED constant-current drive circuit, cost is high, can only realize the technological deficiency that drives constant current, the utility model discloses a kind of LED constant-current drive circuit.
LED constant-current drive circuit described in the utility model, comprise and exchange input stage and the transformer being connected with the DC output end that exchanges input stage, also comprise constant-current control circuit, described constant-current control circuit is by constant current control chip, power tube, be connected to the current sampling resistor between power tube source class and ground, detect the feedback loop composition of transformer secondary output end voltage, the grid control end of described constant current control chip connects the grid of power tube, the source class of described power tube connects the current sample end of constant current control chip, the output of described feedback loop connects the voltage sample end of constant current control chip, constant current control chip also possesses power factor correction pin, and described power factor correction pin is connected with the common port on the first former limit and the second former limit.
Preferably, described feedback control loop is made up of optocoupler, current conversion chip, described current conversion chip gathers output voltage and transformer secondary current, and current signal is inputted to the light-emitting component in optocoupler, and the voltage output end of described optocoupler is connected with the voltage sample end of constant current control chip.
Further, also comprise the first divider resistance and second divider resistance of series connection, be connected between transformer secondary and ground, described the first divider resistance is connected the voltage sample end of current conversion chip with the common port of the second divider resistance.
Further, the current sample end of described current conversion chip is connected by sampling diode with the coil mid point of transformer secondary, and the negative pole of described sampling diode connects current sample end.
More specifically, described current conversion chip is AP4313.
Preferably, described constant current control chip is L6562D.
Further, between the compensation end of described constant current control chip L6562D and voltage sample end, be connected with RC compensating network.
Further, described RC compensating network is made up of the first compensating resistance, the second compensating resistance and building-out capacitor, described the first compensating resistance is connected between compensation end and voltage sample end, after described the second compensating resistance and building-out capacitor series connection, is connected between compensation end and voltage sample end.
Preferably, described power tube grid is connected with voltage stabilizing didoe between ground, and described power tube grid is connected with gate protection resistance between grid control end.
Preferably, between the live wire of described interchange input stage and zero line, be connected with piezo-resistance, on described live wire, be in series with fuse resistor.
Adopt LED constant-current drive circuit described in the utility model, with respect to tradition application, simplified LED drive circuit structure, when reducing the cost that LED drives, dwindled volume.Use this programme can make the LED product of High Power Factor, high efficiency isolated form constant current driving.
Brief description of the drawings
Fig. 1 is a kind of embodiment structural representation of a kind of LED constant-current drive circuit described in the utility model;
In figure, Reference numeral name is called: the L-live wire N-zero line RF-fuse resistor RV-piezo-resistance F1-full bridge rectifier L1-first former limit of former limit L2-second L3-secondary D1-sampling diode D2-sustained diode 3-voltage stabilizing didoe Q-power tube R1-current sampling resistor R2-first current-limiting resistance R3-first divider resistance R4-second divider resistance R5-second current-limiting resistance R6-gate protection resistance R 7-second compensating resistance R8-the first compensating resistance C-building-out capacitor F2-optocoupler GT-grid control end CS-current sample end ZCD-power factor correction pin EA-compensation end INV-voltage sample end.
Embodiment
Below in conjunction with accompanying drawing, embodiment of the present utility model is described in further detail.
Embodiment 1
LED constant-current drive circuit described in the utility model, comprise and exchange input stage and the transformer being connected with the DC output end that exchanges input stage, also comprise constant-current control circuit, described constant-current control circuit is by constant current control chip, power tube, be connected to the current sampling resistor R1 between power tube source class and ground, detect the feedback loop composition of transformer secondary output end voltage, the grid control end of described constant current control chip connects the grid of power tube, the source class of described power tube connects the current sample end of constant current control chip, the output of described feedback loop connects the voltage sample end of constant current control chip, constant current control chip also possesses power factor correction pin ZCD, and described power factor correction pin is connected with the common port of the first former limit L1 and the second former limit L2.
The utility model belongs to a kind of application mode for driving LED constant current of Switching Power Supply, utilize transformer, power tube Q and sustained diode 2 to realize flyback topological structure, according to the sample mode of control loop, Switching Power Supply can be divided into current mode switch power supply and voltage-type Switching Power Supply, voltage-type is only sampled to output voltage, signal after sampling is input in error amplifier, error amplifier is by amplifying the error of output voltage, regulating impulse bandwidth modulation signals (PWM), thereby the duty cycle of switching of power ratio control switching tube.Current mode switch power supply is except sampling to output voltage, also pass through the sampling of inductive current regulating impulse bandwidth modulation signals together with voltage signal, thereby the duty cycle of switching to power switch pipe regulates, current sample mode is rapider to the adjusting of control loop.
The utility model adopts current control mode, output voltage and power tube current are sampled, output voltage utilizes feedback loop to sample, feedback loop can be by divider resistance string to output voltage dividing potential drop post-sampling, also can be by output voltage step-down post-sampling, current sample adopts at power tube Q source electrode and connects sampling resistor R1, to the realization of sampling of R1 terminal voltage.
Exchanging input stage can adopt common full bridge rectifier F1 to realize, with respect to Half bridge rectifier, full-bridge rectification mode efficiency is higher, for improving ac input end fail safe, can between the live wire of interchange input stage and zero line, be connected with piezo-resistance RV, on described live wire, be in series with fuse resistor RF, reduce the impact of surge voltage to internal components, fuse resistor fusing when large electric current, turn-off current path.
Constant current control chip also possesses power factor correction pin, and described power factor correction pin is connected with the common port on the first former limit and the second former limit.The object of power factor correction is that the waveform of the voltage and current of input is calibrated to the as far as possible consistent perfect condition of phase place, in the time that initial phase is consistent, phase changing capacity in same time is consistent and can obtains high power factor.The mean value of electric current in a complete half-wave keeps phase place consistent with voltage, is the perfect condition that switch power supply power factor is proofreaied and correct.Circuit of power factor correction is the prior art that many chips can be realized.Described constant current control chip can be selected L6562D, and L6562D is a current mode switch power supply control IC, adopts the control of PFC(pulse frequency) control model, power consumption is little, and power factor correction rate is high.
The utility model, by output current sampling feedback control output voltage, meanwhile, is realized power factor correction by the biasing winding sampling of transformer primary side.Power factor > 0.9, efficiency > 85%, the technical indicator of constant output current rate within ± 5% are realized.
Embodiment 2
The present embodiment provides a kind of preferred implementation to feedback control loop, feedback control loop described in the present embodiment is made up of optocoupler, current conversion chip, described current conversion chip gathers output voltage and transformer secondary current, current signal is inputted to the light-emitting component in optocoupler, and the voltage output end of described optocoupler is connected with the voltage sample end of constant current control chip.Current conversion chip gathers transformer secondary L3 electric current, current signal is set multiplication factor according to the output voltage gathering, be input in optic coupling element, optocoupler F2 is as shown in Figure 1 made up of light-emitting diode and phototriode, light-emitting diode receives luminous irradiation phototriode after the electric current of current conversion chip output, phototriode conducting, thus collector electrode output voltage changed.
The current sample end of current conversion chip can be connected by sampling diode D1 with the coil mid point of transformer secondary, and the negative pole of described sampling diode connects current sample end.Coil mid point current value can represent coil output current preferably, and sampling diode is realized monolateral conducting, avoids coil current to be subject to the impact of feedback loop.
Current conversion chip can be realized by divider resistance string the sampling of output voltage, as shown in Figure 1, is connected to the first divider resistance R3 between transformer secondary and ground is connected current conversion chip voltage sample end with the common port of the second divider resistance R4.Above-mentioned dividing potential drop sample mode is simple in structure, higher output voltage equal proportion can be reduced to lower voltage levvl, to adapt to current conversion chip lower sampled voltage scope conventionally.Current conversion chip can be AP4313.
Embodiment 3
The present embodiment, on the basis of embodiment 1, carries out decision design to loop stability, between the compensation end of constant current control chip L6562D and voltage sample end, is connected with RC compensating network.Frequency compensation is carried out in internal loop control to L6562D, to obtain good frequency stability.
Further, described RC compensating network is made up of the first compensating resistance R8, the second compensating resistance R7 and building-out capacitor C, described the first compensating resistance is connected between compensation end and voltage sample end, after described the second compensating resistance and building-out capacitor series connection, is connected between compensation end and voltage sample end.Above-mentioned RC compensating network can provide a dominant pole and a zero point, according to loop characteristics, and for example input voltage, output voltage, output currents etc. are selected suitable resistance and capacitance, can regulate pole and zero position, obtain good phase margin.
Embodiment 4
The present embodiment is preferably protected structure to power tube, and described power tube grid is to being connected with voltage stabilizing didoe D3 between ground, and described power tube grid is connected with gate protection resistance R 6 between grid control end.Voltage stabilizing didoe is in the time that grid voltage is too high; can automatically puncture to reduce voltage protection grid, gate protection resistance, in the time having large electrostatic potential pulse, is combined to form RC network with grid parasitic capacitance; by electrostatic induced current bleed off, to ground, protection grid is not directly subject to electrostatic impact.
Previously described is each preferred embodiment of the present utility model, preferred implementation in each preferred embodiment is if not obviously contradictory or taking a certain preferred implementation as prerequisite, each preferred implementation arbitrarily stack combinations is used, design parameter in described embodiment and embodiment is only the utility model proof procedure for clear statement utility model people, not in order to limit scope of patent protection of the present utility model, scope of patent protection of the present utility model is still as the criterion with its claims, the equivalent structure that every utilization specification of the present utility model and accompanying drawing content are done changes, in like manner all should be included in protection range of the present utility model.
Claims (10)
1. a LED constant-current drive circuit, comprise and exchange input stage and the transformer being connected with the DC output end that exchanges input stage, it is characterized in that, also comprise constant-current control circuit, described constant-current control circuit is by constant current control chip, power tube, be connected to the current sampling resistor between power tube source class and ground, detect the feedback loop composition of transformer secondary output end voltage, the grid control end of described constant current control chip connects the grid of power tube, the source class of described power tube connects the current sample end of constant current control chip, the output of described feedback loop connects the voltage sample end of constant current control chip, constant current control chip also possesses power factor correction pin, and described power factor correction pin is connected with the common port on the first former limit and the second former limit.
2. a kind of LED constant-current drive circuit as claimed in claim 1, it is characterized in that, described feedback control loop is made up of optocoupler, current conversion chip, described current conversion chip gathers output voltage and transformer secondary current, current signal is inputted to the light-emitting component in optocoupler, and the voltage output end of described optocoupler is connected with the voltage sample end of constant current control chip.
3. a kind of LED constant-current drive circuit as claimed in claim 2, it is characterized in that, also comprise the first divider resistance and second divider resistance of series connection, be connected between transformer secondary and ground, described the first divider resistance is connected the voltage sample end of current conversion chip with the common port of the second divider resistance.
4. a kind of LED constant-current drive circuit as claimed in claim 2, is characterized in that, the current sample end of described current conversion chip is connected by sampling diode with the coil mid point of transformer secondary, and the negative pole of described sampling diode connects current sample end.
5. a kind of LED constant-current drive circuit as described in claim 2-4 any one, is characterized in that, described current conversion chip is AP4313.
6. a kind of LED constant-current drive circuit as claimed in claim 1, is characterized in that, described constant current control chip is L6562D.
7. a kind of LED constant-current drive circuit as claimed in claim 6, is characterized in that, between the compensation end of described constant current control chip L6562D and voltage sample end, is connected with RC compensating network.
8. a kind of LED constant-current drive circuit as claimed in claim 7, it is characterized in that, described RC compensating network is made up of the first compensating resistance, the second compensating resistance and building-out capacitor, described the first compensating resistance is connected between compensation end and voltage sample end, after described the second compensating resistance and building-out capacitor series connection, is connected between compensation end and voltage sample end.
9. a kind of LED constant-current drive circuit as claimed in claim 1, is characterized in that, described power tube grid is connected with voltage stabilizing didoe between ground, and described power tube grid is connected with gate protection resistance between grid control end.
10. a kind of LED constant-current drive circuit as claimed in claim 1, is characterized in that, between the live wire of described interchange input stage and zero line, is connected with piezo-resistance, on described live wire, is in series with fuse resistor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320866207.8U CN203761627U (en) | 2013-12-26 | 2013-12-26 | LED constant current drive circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320866207.8U CN203761627U (en) | 2013-12-26 | 2013-12-26 | LED constant current drive circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN203761627U true CN203761627U (en) | 2014-08-06 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201320866207.8U Expired - Fee Related CN203761627U (en) | 2013-12-26 | 2013-12-26 | LED constant current drive circuit |
Country Status (1)
| Country | Link |
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| CN (1) | CN203761627U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106533140A (en) * | 2017-01-04 | 2017-03-22 | 西南应用磁学研究所 | High-efficiency magnetic tuning device drive circuit |
| CN106996586A (en) * | 2017-05-18 | 2017-08-01 | 浙江帅康电气股份有限公司 | Fresh air linkage controller and the range hood using the linkage controller |
-
2013
- 2013-12-26 CN CN201320866207.8U patent/CN203761627U/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106533140A (en) * | 2017-01-04 | 2017-03-22 | 西南应用磁学研究所 | High-efficiency magnetic tuning device drive circuit |
| CN106996586A (en) * | 2017-05-18 | 2017-08-01 | 浙江帅康电气股份有限公司 | Fresh air linkage controller and the range hood using the linkage controller |
| CN106996586B (en) * | 2017-05-18 | 2023-07-28 | 浙江帅康电气股份有限公司 | Fresh air linkage controller and range hood using same |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20140806 Termination date: 20171226 |