CN203423826U - Led power supply circuit - Google Patents
Led power supply circuit Download PDFInfo
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- CN203423826U CN203423826U CN201320393659.9U CN201320393659U CN203423826U CN 203423826 U CN203423826 U CN 203423826U CN 201320393659 U CN201320393659 U CN 201320393659U CN 203423826 U CN203423826 U CN 203423826U
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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
The utility model discloses an LED power supply circuit including a rectification filtering circuit used for performing rectification filtering of input AC power source; a transformer with primary terminal input of voltage being rectified and filtered and secondary terminal output of DC voltage; a DC converting circuit performing DC-DC conversion of the DC voltage output from a secondary terminal of the transformer and reducing output ripple to less than 300mv; a power control and pulse width modulation circuit correcting power factors and outputting pulse width modulation signals; and a switch tube connected with a primary terminal of the transformer in series, receiving the pulse width modulation signals, being switched on or switched off according to the pulse width modulation signals and used for controlling input voltage of the primary terminal of the transformer. Since the DC converting circuit reduces output ripple of DC voltage to less than 300mv, the output DC voltage becomes high in stability. Therefore, flickering phenomenon of an LED luminescent device can be reduced substantially when the output DC voltage is applied to a working power source of the LED luminescent device.
Description
Technical field
The utility model relates to lighting field, particularly relates to a kind of LED power supply circuits of T8 type LED fluorescent tube.
Background technology
Along with the development of modern lighting technology, also more and more higher in the requirement aspect environmental protection to lighting.What traditional fluorescent tube adopted is cold fluorescent tube, although higher than the energy conversion efficiency of incandescent lamp, in its fluorescent tube, the mercury of perfusion can enter environment around when fluorescent tube is destroyed, pollutes.LED luminescent device is combined and just produced LED fluorescent lamp with fluorescent lamp technology.LED fluorescent tube, than traditional incandescent lamp, possesses energy-conservation advantage; Than traditional fluorescent lamp, possesses again the advantage of environmental protection.Therefore LED fluorescent lamp is following illumination trend, is widely used in illumination.
Traditional LED fluorescent lamp is too pursued energy-conservation, so its power factor is generally very high, all surpasses 90%.Yet under so high power factor, LED luminescent device is easy to occur the phenomenon of light-emitting flash.Under the condition of this LED fluorescent lamp lighting, while adopting the image capture device collection image of high frame per second, flicker shows more obviously.
Utility model content
Based on this, be necessary to provide a kind of LED power supply circuits of the LED of avoiding fluorescent lamp flicker.
Power supply circuits, comprising: current rectifying and wave filtering circuit, carries out rectifying and wave-filtering to the AC power of input; Transformer, the described voltage through rectifying and wave-filtering of elementary input, secondary output dc voltage; DC transfer circuit, carries out the conversion of DC-to-DC by the direct voltage of described transformer secondary output output and reduces in output ripple to 300 millivolt; Power is controlled and pulse width modulation circuit, and power factor is proofreaied and correct and output pulse width modulation signal; Switching tube, is connected in series with described primary, and receives described pulse width modulating signal, according to described pulse width modulating signal opening and closing, for controlling the input voltage of described primary.
Because DC transfer circuit is reduced to galvanic output ripple in 300 millivolts, make the direct current of output more steady, while using it for the working power of LED, can significantly reduce the scintillation of LED luminescent device.
Accompanying drawing explanation
Fig. 1 is the LED power supply circuits module map of an embodiment;
Fig. 2 is the LED power supply circuits schematic diagram of the first preferred embodiment;
Fig. 3 is the LED power supply circuits schematic diagram of the second preferred embodiment.
Embodiment
As shown in Figure 1, be the LED power supply circuits module map of an embodiment.These LED power supply circuits 10 comprise current rectifying and wave filtering circuit 100, transformer T1, DC transfer circuit 200, power control and pulse width modulation circuit 300 and switching tube Q1.Wherein the AC power of 100 pairs of inputs of current rectifying and wave filtering circuit is carried out rectifying and wave-filtering.Elementary through the voltage input transformer T1 of rectifying and wave-filtering, after the voltage transformation of transformer T1 from secondary output dc voltage.DC transfer circuit 200 is carried out the conversion of DC-to-DC (DC-DC) by the direct voltage of described transformer secondary output output and is reduced in output ripple to 300 millivolt.Switching tube Q1 and elementary serial connection of described transformer T1, and reception is controlled from power and pulse width modulation (PWM) signal of pulse width modulation circuit 300, according to described pulse width modulating signal opening and closing, for controlling the elementary input voltage of described transformer T1.Power is controlled and above-mentioned pulse width modulating signal is proofreaied and correct and exported to 300 pairs of power factors of pulse width modulation circuit.
Because DC transfer circuit 200 is reduced to galvanic output ripple in 300 millivolts, make the direct current of output more steady, while using it for the working power of LED, can significantly reduce the scintillation of LED luminescent device.
As shown in Figure 2, be the circuit theory diagrams of the utility model LED power supply circuits the first preferred embodiment.
Current rectifying and wave filtering circuit 100 comprises rectifier bridge DB1, and AC power, from two input inputs of rectifier bridge DB1, is exported from two voltage output ends after rectifier bridge DB1 rectification.One of them voltage output end of rectifier bridge DB1 is exported commutating voltage and is connected to one of them input of two elementary voltage input ends of transformer T1, another voltage output end ground connection of rectifier bridge DB1.Capacitor C 2 is connected between one end and ground of rectifier bridge DB1 output commutating voltage.After resistance R 2 and capacitor C 3 are in parallel, connect with resistance R 7 and diode D8, the series arm of formation is connected between two elementary voltage input ends of transformer T1.Wherein the positive pole of diode D8 another voltage input end elementary with transformer T1 is connected, and negative pole is connected with resistance R 7.
The AC power of input rectifying filter circuit 100 can also be passed through the processing of the anti-electromagnetic interference circuit 400 of front end.The protective tube F1 of anti-electromagnetic interference circuit 400 is connected with AC power live wire one end, and be connected in series with inductance coil L1 and resistance R 1 parallel with one another, the serial connection branch road forming is connected with one of them input of magnet exciting coil LF1, and another input of magnet exciting coil LF1 is connected with the zero line of alternating voltage.Two outputs of magnet exciting coil LF1 are connected with two inputs of another magnet exciting coil LF2, and capacitor C X1 is connected between two outputs of magnet exciting coil LF1.Two outputs of magnet exciting coil LF2 are connected with current rectifying and wave filtering circuit 100 as two outputs of anti-electromagnetic interference circuit 400.
Two secondary outputs of transformer T1 are connected with DC transfer circuit 200.After one of them secondary output of transformer T1 is connected with the diode D1 of DC transfer circuit 200, output voltage is to LED drive circuit 500.Another output head grounding of transformer T1.In DC transfer circuit 200, after resistance R 3 and capacitor C 4 serial connections, be connected in parallel on diode D1 two ends.Wherein the positive pole of diode D1 is connected with the secondary of transformer T1.Electrochemical capacitor C6 two ends are connected between diode D1 negative pole and ground.Capacitor C 32 and resistance R 15 are all in parallel with electrochemical capacitor C6.
Power is controlled and pulse width modulation circuit 300 be take chip SN03A and carried out power factor correction and pulse width modulation as core.
In power control and pulse width modulation circuit 300, the pin 1 of chip SN03A is by resistance R 9 and resistance R 11 ground connection, and capacitor C 13 is in parallel with resistance R 11.Between the pin 1 of chip SN03A and pin 2, connect capacitor C 22, the pin 1 of chip SN03A is also connected capacitor C 12 and the resistance R 21 of connecting with pin 2.
The voltage of self-rectifying bridge DB1 output carries out dividing potential drop through resistance R 22, R14 and R19, and wherein the dividing potential drop on R19 is inputted the pin 3 of chip SN03A, and R19 connects with capacitor C 11.
The pin 4 of chip SN03A is through resistance R 25 and resistance R 16 ground connection, and pin 4 is also through capacitor C 15 ground connection.
The elementary coil that also comprises one end ground connection of transformer T1, this coil and aforesaid elementary coil coupling obtain voltage.Another unearthed end of the coil of this ground connection is connected to the pin 5 of chip SN03A by resistance R 12.
The Connection Element of the peripheral circuit of said chip SN03A, parameter and mode are not limited to above-mentioned, can also have flexible mode, as long as can realize its capability correction and pulse width modulation function.
After resistance R 24 and diode D5 parallel connection, be connected between the pin 7 of chip SN03A and the control end of switching tube Q1.
One end of the voltage of rectifier bridge DB1 output is connected to the pin 8 of chip SN03A through resistance R 38 and resistance R 1.Between pin 1 and pin 8, also connect voltage stabilizing didoe ZD1, wherein the positive pole of voltage stabilizing didoe ZD1 is connected with pin 1.Between elementary another coil of pin 8 and transformer T1, also connect diode D6 and resistance R 13.
Chip SN03A also accepts the FEEDBACK CONTROL from secondary output end.This FEEDBACK CONTROL is mainly that the optocoupler that is EL817 through model carries out.Wherein the light accepting part of this optocoupler divides U2 to be connected in power control and pulse width modulation circuit 300, specifically between pin 8 and resistance R 11.The luminous component P1A of this optocoupler is connected in sample circuit 600.Luminous component P1A is in parallel with resistance R 13, and is connected in series with voltage-stabiliser tube ZD2, resistance R 8, TL431U2.Wherein the positive pole of voltage-stabiliser tube ZD2 connects the positive pole of luminous component P1A by resistance R 8.The negative pole of luminous component P1A is connected with the negative pole of TL431U2, the plus earth of TL431U2.Resistance R 30 and capacitor C 35 are connected in parallel on the anodal of TL431 and with reference between the utmost point.Resistance R 32 and capacitor C 35 are serially connected between voltage sample end and ground.Resistance R 29 and capacitor C 34 are serially connected between the negative pole and resistance R 32 of luminous component P1A.
Power supply circuits based on the first preferred embodiment, introduce its circuit working principle as follows.
The AC power of 100 pairs of inputs of current rectifying and wave filtering circuit is carried out rectifying and wave-filtering.The described voltage through rectifying and wave-filtering of elementary input of transformer T1, secondary output dc voltage.DC transfer circuit 200 is carried out the conversion of DC-to-DC by the direct voltage of described transformer T1 time level output and is reduced in output ripple to 300 millivolt.Power is controlled and pulse width modulation circuit 300 be take chip SN03A and power factor proofreaied and correct and output pulse width modulation signal as core.Switching tube Q1 and elementary serial connection of described transformer T1, and receive described pulse width modulating signal, according to described pulse width modulating signal opening and closing, for controlling the elementary input voltage of described transformer T1.
Because DC transfer circuit is reduced to galvanic output ripple in 300 millivolts, make the direct current of output more steady, while using it for the working power of LED, can significantly reduce the scintillation of LED luminescent device.
As shown in Figure 3, be the circuit theory diagrams of the utility model LED power supply circuits the second preferred embodiment.
Compare with the power supply circuits of the first preferred embodiment, the second preferred embodiment is basic identical on the circuit structure of current rectifying and wave filtering circuit 100 DC converting circuit 200 and anti-electromagnetic interference circuit 400, please refer to concrete circuit theory diagrams, is not repeated herein.
The main distinction of the power supply circuits of the power supply circuits of the second preferred embodiment and the first preferred embodiment is power control and pulse width modulation circuit 300 and mirror image constant voltage circuit 500.Details are as follows.
In figure 3, the second preferred embodiments, pulse width modulation circuit 300 be take chip SY5800A and is carried out power factor correction and pulse width modulation as core.
The pin 1 of chip SY5800A is by resistance and capacitance network ground connection, in parallel with capacitor C 3 after capacitor C 4 and resistance R 25 series connection in this resistance and capacitance network.The pin 3 of chip SY5800A is connected with the output of switching tube Q1 and passes through resistance R 18 ground connection.Pin 4 ground connection of chip SY5800A.The pin 5 of chip SY5800A is connected to the control end of switching tube Q1 by resistance R 15, be connected in parallel on resistance R 15 two ends after resistance R 21 and diode D3 serial connection simultaneously.Wherein, the positive pole of diode D3 is connected with resistance R 21, and negative pole is connected with pin 5.The control end of switching tube Q1 is by resistance R 17 ground connection.
With reference to figure 3, the elementary coil that also comprises one end ground connection of transformer T1, this coil obtains voltage with the elementary coil coupling being connected with current rectifying and wave filtering circuit 100 of transformer T1.Another unearthed end of the coil of this ground connection is by resistor voltage divider network ground connection, and this resistor voltage divider network comprises resistance R 13 and the resistance R 16 of resistance R 12, parallel connection, the voltage input pin 2 of getting in resistance R in parallel 13 and resistance R 16.Another unearthed end of the coil of this ground connection is also connected with the pin 6 of chip SY5800A by diode D2, resistance R 11.Pin 6 is also by capacitor C 9 ground connection and by voltage-stabiliser tube ZD1 ground connection.Pin 6 is also connected to the voltage output end of rectifier bridge by resistance R 5 and resistance R 6.Contact resistance R14 between the pin 6 of chip SY5800A and pin 7.Pin 8 ground connection of chip SY5800A.
Mirror image constant voltage circuit 500 comprises triode Q2, and the voltage output end of DC converting unit 200 is connected with the collector electrode of triode Q2, the base stage of triode Q2 is connected with the collector electrode of triode Q3, the emitter of triode Q3 is connected with the collector electrode of triode Q2.The base stage of triode Q2 is connected with the positive pole of voltage-stabiliser tube ZD2 by resistance R 28, and the negative pole of voltage-stabiliser tube ZD2 is connected with the negative pole of diode D11, and the positive pole of diode D11 is connected with the collector electrode of diode Q2.The two ends of resistance R 27 are connected to the positive pole of voltage-stabiliser tube ZD2 and the positive pole of diode D11.Electrochemical capacitor C11 is anodal to be connected with voltage-stabiliser tube ZD2 is anodal.
The Connection Element of the peripheral circuit of said chip SY5800A, parameter and mode are not limited to above-mentioned, can also have flexible mode, as long as can realize its capability correction and pulse width modulation function.
Power supply circuits based on the second preferred embodiment, introduce its circuit working principle as follows.
The AC power of 100 pairs of inputs of current rectifying and wave filtering circuit is carried out rectifying and wave-filtering.The described voltage through rectifying and wave-filtering of elementary input of transformer T1, secondary output dc voltage.DC transfer circuit 200 is carried out the conversion of DC-to-DC by the direct voltage of described transformer T1 time level output and is reduced in output ripple to 300 millivolt.Power is controlled and pulse width modulation circuit 300 be take chip SY5800A and power factor proofreaied and correct and output pulse width modulation signal as core.Switching tube Q1 and elementary serial connection of described transformer T1, and receive described pulse width modulating signal, according to described pulse width modulating signal opening and closing, for controlling the elementary input voltage of described transformer T1.
Because DC transfer circuit is reduced to galvanic output ripple in 300 millivolts, make the direct current of output more steady, while using it for the working power of LED, can significantly reduce the scintillation of LED luminescent device.
The above embodiment has only expressed several execution mode of the present utility model, and it describes comparatively concrete and detailed, but can not therefore be interpreted as the restriction to the utility model the scope of the claims.It should be pointed out that for the person of ordinary skill of the art, without departing from the concept of the premise utility, can also make some distortion and improvement, these all belong to protection range of the present utility model.Therefore, the protection range of the utility model patent should be as the criterion with claims.
Claims (8)
1. LED power supply circuits, comprising:
Current rectifying and wave filtering circuit, carries out rectifying and wave-filtering to the AC power of input;
Transformer, the described voltage through rectifying and wave-filtering of elementary input, secondary output dc voltage;
DC transfer circuit, carries out the conversion of DC-to-DC by the direct voltage of described transformer secondary output output and reduces in output ripple to 300 millivolt;
Power is controlled and pulse width modulation circuit, and power factor is proofreaied and correct and output pulse width modulation signal;
Switching tube, is connected in series with described primary, and receives described pulse width modulating signal, according to described pulse width modulating signal opening and closing, for controlling the input voltage of described primary.
2. LED power supply circuits according to claim 1, is characterized in that, described power is controlled and pulse width modulation circuit comprises chip SN03A and peripheral circuit thereof.
3. LED power supply circuits according to claim 1, is characterized in that, described power is controlled and pulse width modulation circuit comprises chip SY5800A and peripheral circuit thereof.
4. LED power supply circuits according to claim 1, is characterized in that, described DC transfer circuit comprises diode D1, resistance R 3, capacitor C 4, electrochemical capacitor C6, capacitor C 32 and resistance R 15; After described resistance R 3 and capacitor C 4 serial connections, be connected in parallel on diode D1 two ends; The positive pole of described diode D1 is connected with the secondary of transformer; Electrochemical capacitor C6 two ends are connected between diode D1 negative pole and ground; Capacitor C 32 and resistance R 15 are all in parallel with electrochemical capacitor C6.
5. LED power supply circuits according to claim 4, is characterized in that, also comprise mirror image constant voltage circuit; Described mirror image constant voltage circuit comprises triode Q2, and the voltage output end of described DC converting unit is connected with the collector electrode of triode Q2, the base stage of triode Q2 is connected with the collector electrode of triode Q3, the emitter of triode Q3 is connected with the collector electrode of triode Q2; The base stage of triode Q2 is connected with the positive pole of voltage-stabiliser tube ZD2 by resistance R 28, and the negative pole of voltage-stabiliser tube ZD2 is connected with the negative pole of diode D11, and the positive pole of diode D11 is connected with the collector electrode of diode Q2; The two ends of resistance R 27 are connected to the positive pole of voltage-stabiliser tube ZD2 and the positive pole of diode D11; Electrochemical capacitor C11 is anodal to be connected with voltage-stabiliser tube ZD2 is anodal.
6. LED power supply circuits according to claim 1, is characterized in that, described current rectifying and wave filtering circuit comprises rectifier bridge DB1, and AC power, from two input inputs of rectifier bridge DB1, is exported from two voltage output ends after rectifier bridge DB1 rectification; One of them voltage output end of rectifier bridge DB1 is exported commutating voltage and is connected to one of them input of two voltage input ends of described primary, another voltage output end ground connection of rectifier bridge DB1; Capacitor C 2 is connected between one end and ground of rectifier bridge DB1 output commutating voltage; After resistance R 2 and capacitor C 3 are in parallel, connect with resistance R 7 and diode D8, the series arm of formation is connected between two voltage input ends of described primary; Wherein the positive pole of diode D8 is connected with another voltage input end of described primary, and negative pole is connected with resistance R 7.
7. LED power supply circuits according to claim 4, is characterized in that, also comprise anti-electromagnetic interference circuit; The protective tube F1 of described anti-electromagnetic interference circuit is connected with AC power live wire one end, and be connected in series with inductance coil L1 and resistance R 1 parallel with one another, the serial connection branch road forming is connected with one of them input of magnet exciting coil LF1, and another input of magnet exciting coil LF1 is connected with the zero line of alternating voltage; Two outputs of magnet exciting coil LF1 are connected with two inputs of another magnet exciting coil LF2, and capacitor C X1 is connected between two outputs of magnet exciting coil LF1; Two outputs of magnet exciting coil LF2 are connected with current rectifying and wave filtering circuit as two outputs of anti-electromagnetic interference circuit.
8. LED power supply circuits according to claim 2, is characterized in that, also comprise sample circuit, for the described transformer-secondary voltage of sampling, to comprising that the power of described chip SN03A is controlled and pulse width modulation circuit carries out FEEDBACK CONTROL.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320393659.9U CN203423826U (en) | 2013-07-03 | 2013-07-03 | Led power supply circuit |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201320393659.9U CN203423826U (en) | 2013-07-03 | 2013-07-03 | Led power supply circuit |
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| CN203423826U true CN203423826U (en) | 2014-02-05 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103338560A (en) * | 2013-07-03 | 2013-10-02 | 深圳市通普科技有限公司 | LED supply circuit |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103338560A (en) * | 2013-07-03 | 2013-10-02 | 深圳市通普科技有限公司 | LED supply circuit |
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| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20140205 Termination date: 20170703 |
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