CN204681625U - Input feedforward LED drive circuit - Google Patents
Input feedforward LED drive circuit Download PDFInfo
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- CN204681625U CN204681625U CN201520236611.6U CN201520236611U CN204681625U CN 204681625 U CN204681625 U CN 204681625U CN 201520236611 U CN201520236611 U CN 201520236611U CN 204681625 U CN204681625 U CN 204681625U
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Abstract
Input feedforward LED drive circuit, the power tube comprising direct-flow input end, DC output end, output voltage feedback end, control loop and be connected with control loop; Also comprise the first reference voltage, linear voltage regulator, sampling resistor and Correctional tube, described sampling resistor is connected between DC output end and Correctional tube drain electrode, Correctional tube source electrode connects load LED, the control end of described Correctional tube is connected with linear voltage regulator output, and two inputs of described linear voltage regulator connect common port and first reference voltage of Correctional tube and sampling resistor respectively; Described first reference voltage is the divider resistance string be connected between direct-flow input end and ground.The utility model is by the rechargeable energy path turn-on and turn-off of control inputs to output capacitance, achieve transmitting energy to supply as required, adopt in direct current input feedback to error amplifier the Direct Sampling achieved input direct voltage, improve input response speed.
Description
Technical field
The utility model belongs to integrated circuit (IC) design field, relates to Switching Power Supply, particularly a kind of input feedforward LED drive circuit.
Background technology
Along with the development of high-voltage LED lamp pearl and LED drive power are to the more and more harsh requirement of cost and volume, the high voltage and constant current Linear Driving method of low cost obtains certain technology innovation and application in the past few years.But there is low reliability all the time in Linear Driving method at present, high coupling is required to input voltage and output lamp pearl, the shortcomings such as input and output voltage fluctuation cannot be born, hinder in the production in enormous quantities and safety applications that Linear Driving method is really applied to LED illumination.
Utility model content
For overcoming the deficiency existing for existing LED drive chip employing linear voltage regulator step-down control, the utility model discloses a kind of input feedforward LED drive circuit.
Input described in the utility model feedforward LED drive circuit, comprises direct-flow input end, DC output end, output voltage feedback end, the control loop controlling power tube duty cycle of switching according to output voltage feedback end and the power tube be connected with control loop;
Also comprise the first reference voltage, linear voltage regulator LDO, sampling resistor R4 and Correctional tube, described sampling resistor R4 is connected between DC output end VOUT and Correctional tube drain electrode, Correctional tube source electrode connects load LED, the control end of described Correctional tube is connected with linear voltage regulator output, and two inputs of described linear voltage regulator connect common port and first reference voltage of Correctional tube and sampling resistor respectively; The common port of described Correctional tube and load LED is as output voltage feedback end; Described first reference voltage is the divider resistance string be connected between direct-flow input end and ground.
Preferably, described control loop comprises logic drive circuit, PWM comparator, error amplifier, the second reference voltage and current sampling circuit, two inputs of described error amplifier connect the second reference voltage and output voltage feedback end respectively, two inputs of described PWM comparator connect the output of error amplifier and current sampling circuit respectively, the output of described PWM comparator connects logic drive circuit, and the output of described logic drive circuit connects power tube control end.
Preferably, described current sampling circuit comprises and is connected to current sampling resistor between power tube source electrode and ground and current-to-voltage convertor, and the input of described current-to-voltage convertor connects power tube source electrode, and output is as the output of current sampling circuit.
Preferably, the protective circuit that output is connected with logic drive circuit is also comprised.
The utility model is by being applied in booster type LED drive circuit in conjunction with switched-capacitor circuit and linear constant current LDO, control inputs is to the rechargeable energy path turn-on and turn-off of output capacitance, LDO realizes the ripple-free constant current of LED and fed-back output voltage to switching capacity loop, achieve transmitting energy to supply as required, adopt in direct current input feedback to error amplifier the Direct Sampling achieved input direct voltage, improve input response speed.
Accompanying drawing explanation
Fig. 1 illustrates a kind of embodiment structural representation of the present utility model.
Reference numeral name in Fig. 1 is called
VIN-direct-flow input end VOUT-DC output end M1-power tube M2-Correctional tube LDO-linear voltage regulator D1-sustained diode 2-load LED R1-first divider resistance R2-second divider resistance R3-current sampling resistor R4-sampling resistor COUT-output capacitance L-inductance VREF1-first reference voltage V REF2-second reference voltage.
Embodiment
Below in conjunction with accompanying drawing, embodiment of the present utility model is described in further detail.
Input described in the utility model feedforward LED drive circuit, comprises direct-flow input end, DC output end, output voltage feedback end, the control loop controlling power tube duty cycle of switching according to output voltage feedback end and the power tube be connected with control loop;
Also comprise the first reference voltage V REF, LDO, sampling resistor R4 and Correctional tube M2, described sampling resistor is connected between DC output end and Correctional tube drain electrode, Correctional tube source electrode connects load LED, the control end of described Correctional tube is connected with LDO output, and two inputs of described LDO connect common port and first reference voltage of Correctional tube and sampling resistor respectively; The common port of described Correctional tube and load LED is as output voltage feedback end;
Described control loop comprises logic drive circuit, PWM comparator, error amplifier, the second reference voltage and alternating current sampling circuit, two inputs of described error amplifier connect the second reference voltage and output voltage feedback end respectively, two inputs of described PWM comparator connect the output of error amplifier and alternating current sampling circuit respectively, the output of described PWM comparator connects logic drive circuit, and the output of described logic drive circuit connects power tube control end.
Concrete, described current sampling circuit comprises and is connected to current sampling resistor R3 between power tube source electrode and ground and current-to-voltage convertor, and the input of described current-to-voltage convertor connects power tube source electrode, and output is as the output of current sampling circuit.
As shown in Figure 1, system is divided into two large divisions, and power tube M1 and output capacitance COUT forms the turn-on and turn-off of switching capacity controls transfer to COUT energy pathway.LDO and Correctional tube M2 is control LED output current, and it is connected with output LED string, and the energy of LDO and LED conducting is from output capacitance COUT.The drain terminal of M2 connects the anode LED+ of load LED strip, and LED+ can reflect the size of energy on COUT electric capacity in real time, and the positive input of LDO is connected with the first reference voltage.Correctional tube can be PMOS or PNP pipe.
Adopt the control mode of above-mentioned LDO and Correctional tube, eliminate the fluctuation of pressure drop because output voltage fluctuates on the load LED caused, make LED output current more stable, make the output voltage feedback end voltage constant being input to Inner Control Loop simultaneously, reduce the power loss of control loop.
Take input voltage as 220V civil power, output voltage is for driving 28-60 LED light-emitting diode, and output voltage is for example is tested in the excursion of 80-200V, and the loss of control loop only changes about 0.2W.Can think that loss and output voltage are substantially irrelevant.
Second reference voltage V REF2 is formed by the divider resistance string dividing potential drop be connected between direct-flow input end and ground, as shown in Figure 1, the common port of the first divider resistance R1 and the second divider resistance R2 is that divider node is as the second reference voltage, second reference voltage is obtained by the voltage of direct-flow input end, make in booster type LED drive circuit, the change of input voltage can rapid feedback to control loop, make the change of the change of control loop to input voltage timely Modulating Power pipe duty ratio.
Control loop preferably adopts current feedback form, described control loop comprises logic drive circuit, PWM comparator, error amplifier, the second reference voltage and alternating current sampling circuit, two inputs of described error amplifier connect the second reference voltage and output voltage feedback end respectively, two inputs of described PWM comparator connect the output of error amplifier and alternating current sampling circuit respectively, the output of described PWM comparator connects logic drive circuit, and the output of described logic drive circuit connects power tube control end.Wherein the first reference voltage V REF1 can be produced by bandgap voltage reference output voltage dividing potential drop, and dividing potential drop can adopt conventional electric resistance partial pressure form.
Preferably, can also protective circuit be set, such as overvoltage crowbar, overheating protection circuit etc., controls logic drive circuit when detecting that output voltage is excessive or power tube current is excessive and close power tube.
Previously described is each preferred embodiment of the present utility model, preferred implementation in each preferred embodiment is if not obviously contradictory or premised on a certain preferred implementation, each preferred implementation can stack combinations use arbitrarily, design parameter in described embodiment and embodiment is only the utility model proof procedure in order to clear statement utility model people, and be not used 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 change that every utilization specification of the present utility model and accompanying drawing content are done, in like manner all should be included in protection range of the present utility model.
Claims (4)
1. input feedforward LED drive circuit, comprises direct-flow input end, DC output end, output voltage feedback end, the control loop controlling power tube duty cycle of switching according to output voltage feedback end and the power tube be connected with control loop;
It is characterized in that, also comprise the first reference voltage, linear voltage regulator, sampling resistor and Correctional tube, described sampling resistor is connected between DC output end and Correctional tube drain electrode, Correctional tube source electrode connects load LED, the control end of described Correctional tube is connected with linear voltage regulator output, and two inputs of described linear voltage regulator connect common port and first reference voltage of Correctional tube and sampling resistor respectively; The common port of described Correctional tube and load LED is as output voltage feedback end; Described first reference voltage is the divider resistance string be connected between direct-flow input end and ground.
2. input feedforward LED drive circuit as claimed in claim 1, is characterized in that,
Described control loop comprises logic drive circuit, PWM comparator, error amplifier, the second reference voltage and current sampling circuit, two inputs of described error amplifier connect the second reference voltage and output voltage feedback end respectively, two inputs of described PWM comparator connect the output of error amplifier and current sampling circuit respectively, the output of described PWM comparator connects logic drive circuit, and the output of described logic drive circuit connects power tube control end.
3. input feedforward LED drive circuit as claimed in claim 2, it is characterized in that, described current sampling circuit comprises and is connected to current sampling resistor between power tube source electrode and ground and current-to-voltage convertor, the input of described current-to-voltage convertor connects power tube source electrode, and output is as the output of current sampling circuit.
4. input feedforward LED drive circuit as claimed in claim 1, is characterized in that, also comprise the protective circuit that output is connected with logic drive circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520236611.6U CN204681625U (en) | 2015-04-20 | 2015-04-20 | Input feedforward LED drive circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520236611.6U CN204681625U (en) | 2015-04-20 | 2015-04-20 | Input feedforward LED drive circuit |
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| Publication Number | Publication Date |
|---|---|
| CN204681625U true CN204681625U (en) | 2015-09-30 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201520236611.6U Active CN204681625U (en) | 2015-04-20 | 2015-04-20 | Input feedforward LED drive circuit |
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| CN (1) | CN204681625U (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2017063608A1 (en) * | 2015-10-16 | 2017-04-20 | 得能创科有限公司 | Current measurement circuit and method for led drive power source |
| CN112333882A (en) * | 2020-10-15 | 2021-02-05 | 佛山市利升光电有限公司 | LED control circuit and lamp |
| CN112688558A (en) * | 2020-12-16 | 2021-04-20 | 维沃移动通信有限公司 | Voltage regulation method, voltage regulation circuit, electronic device, and readable storage medium |
-
2015
- 2015-04-20 CN CN201520236611.6U patent/CN204681625U/en active Active
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2017063608A1 (en) * | 2015-10-16 | 2017-04-20 | 得能创科有限公司 | Current measurement circuit and method for led drive power source |
| CN112333882A (en) * | 2020-10-15 | 2021-02-05 | 佛山市利升光电有限公司 | LED control circuit and lamp |
| CN112688558A (en) * | 2020-12-16 | 2021-04-20 | 维沃移动通信有限公司 | Voltage regulation method, voltage regulation circuit, electronic device, and readable storage medium |
| CN112688558B (en) * | 2020-12-16 | 2022-04-05 | 维沃移动通信有限公司 | Voltage regulation method, voltage regulation circuit, electronic device, and readable storage medium |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C41 | Transfer of patent application or patent right or utility model | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20160418 Address after: 201204 Zhang Heng road Shanghai, Pudong New Area Zhangjiang hi tech Park Lane 666 No. 2 floor 504-511 room 5 Patentee after: Shanghai Bright Power Semiconductor Co.,Ltd. Address before: West high tech Zone Fucheng Road in Chengdu city of Sichuan province 610000 399 No. 6 Building 1 unit 10 floor No. 2 Patentee before: Chengdu Minchuang Science & Technology Co., Ltd. |
|
| CP03 | Change of name, title or address | ||
| CP03 | Change of name, title or address |
Address after: 5 room 504-511, room 2, Lane 666, Zhang Heng Road, Pudong New Area, China (Shanghai) free trade zone, Shanghai, China () Patentee after: Shanghai semiconducto Limited by Share Ltd Address before: 201204 Zhang Heng road Shanghai, Pudong New Area Zhangjiang hi tech Park Lane 666 No. 2 floor 504-511 room 5 Patentee before: Shanghai Bright Power Semiconductor Co.,Ltd. |