CN103313454B - Micro power consumption LED (Light Emitting Diode) lighting source - Google Patents

Abstract

The invention discloses a micro power consumption LED (Light Emitting Diode) lighting source. According to the micro power consumption LED lighting source, narrow pulses of alternating current sine waves before and after the zero crossing point are utilized to obtain appropriate voltages, meanwhile a novel method for generating constant flows is used, and the purposes of energy saving, environmentally friendly, providing optimal designs for achieving the LED intelligent control and providing preferable guarantee for utilization of the LED in different working conditions are achieved. The micro power consumption LED lighting source has the advantages of avoiding light emitting efficiency to be reduced due to large currents or the high junction temperature, generating no high frequency loss and EMI (Electro-Magnetic Interference) and enabling light emitting tubes not to be flashed during to working under the low frequency and enabling the cost, the size, the weight and the power consumption to be reduced by 90 % in comparison with the traditional LED power source.

Description

Micro Energy Lose LED illumination power supply

Technical field

The present invention relates to a kind of Micro Energy Lose LED illumination power supply.

Background technology

Tradition LED illumination power supply present situation, has three kinds of situations:

1) adopt resistance step-down, be mainly used in small-power illumination, efficiency is very low, is only about 5%;

2) adopt capacitance decompression, be mainly used in small-power illumination, power factor is very low, is only about 5%;

3) adopt Switching Power Supply mode, be mainly used in the larger illumination of power, efficiency and power factor are less than 80%.

Width modulation type switching power supply, for unipolarity rectangular pulse, its direct current average voltage Uo depends on the width of rectangular pulse, and pulse is wider, and its direct current average voltage level is higher.Direct current average voltage Uo can by formulae discovery, i.e. Uo=Um × T1/T.In formula, Um is rectangular pulse maximum voltage value; T is the rectangular pulse cycle; T1 is rectangular pulse width.

As can be seen from the above equation, when Um and T is constant, direct current average voltage Uo will be directly proportional to pulse width T 1.Like this, as long as make pulse width increasing and narrow with voltage-stabilized power supply output voltage, the object of burning voltage can just be reached.

The maximum shortcoming of this pulse-width modulation type voltage-stabilized power supply is that efficiency is relatively low, and circuit is complicated, produces strong EMI and disturbs, cause severe contamination to electrical network.

LED illumination power supply feature

The characteristic curve on Fig. 1 left side can be found out, after LED conducting, the tiny variation of forward voltage will cause the very big change of electric current, environment temperature, LED ageing time etc. also will be affected, and the light output of LED is directly relevant to the electric current passed through, when input voltage, environment temperature change, the electric current that must be maintained by LED keeps constant.

The characteristic curve of Fig. 2 can be found out, when LED junction temperature raises, its luminous intensity exported will reduce, and vice versa, and when junction temperature rises to 100 degree, the luminous intensity of White LED is down to initial value 80%.

Summary of the invention

Burst pulse before and after the sinusoidal wave zero crossing of Micro Energy Lose LED photo power utilization civil power, obtain suitable voltage, adopt the new method producing constant current simultaneously, object is energy saving standard, proposing optimal design for realizing LED intelligentized control method, providing more superior guarantee for LED uses in different operating environment.Micro Energy Lose LED illumination power supply, avoids because electric current is excessive or save warm too high reduction luminous efficiency; This mains lighting supply main device is operated in power frequency, and do not produce high-frequency loss and EMI interference, luminous tube does not flash, and cost, volume, weight, power consumption all reduce 90% compared with traditional LED power.

Micro Energy Lose LED illumination power supply includes schematic circuit, symmetrical output circuit, transformer output circuit etc., is described in detail as follows;

Fig. 3 is the schematic circuit of Micro Energy Lose LED illumination power supply, and V1 is amplitude 311V civil power, and drive singal V2, V3, V4, V5 are the square waves of cycle 20ms, pulsewidth 1ms, and delay time is successively; 0ms, 9ms, 10ms, 19ms.Between positive half period, before and after sine voltage zero passage during 1ms, V2, V3 high level, civil power V1 forms loop by D1, NPN FET Q1, R5 to ground, get the sine voltage in 1ms interval before and after the sinusoidal wave zero passage of forward respectively, two direct impulses on resistance R5; Between negative half-cycle, before and after sine voltage zero passage during 1ms, V4, V5 low level, civil power V1 forms loop by D2, PNP FET Q2, R5 to ground, get the sine voltage in 1ms interval before and after the sinusoidal wave zero passage of negative sense respectively, two direct impulses on resistance R5, after one-period, resistance R5 obtain positive and negative four positive negative pulse stuffing voltages.The voltage pulse ripple that resistance R5 obtains is the some of sine voltage, pulsewidth 1ms, is positioned at before and after sinusoidal wave zero passage, two unidirectional pulse ripples before and after zero passage, forms a positive negative pulse stuffing ripple, pulsewidth 2ms, and adjacent two impulse waves are symmetrical about the longitudinal axis.

As shown in Fig. 4 simulation waveform, to get each point voltage corresponding with the driving voltage of each power MOS pipe, it is all the 1ms spike before and after sinusoidal wave zero passage, the wide peaking voltage of 1ms near four zero passages is only got at sinusoidal wave one-period, sine voltage distortion can not be caused, can greatly improve the sine waveform factor on the contrary.

Electric network pollution, power factor is low, and main cause is that capacitive load causes, the feature of capacitive load only utilizes interval voltage near sinusoidal crest, only have this interval just to have outflow of bus current, and rest interval does not have outflow of bus current completely, this just causes power factor low.This power supply utilizes interval voltage near sinusoidal wave trough just, makes this usually not have the interval that electric wave flows out also to have outflow of bus current completely, not only develops a large treasure-house of the energy, greatly improves power factor and the electric network pollution degree of electrical network simultaneously.

Micro Energy Lose LED illumination power supply is made up of reduction voltage circuit and constant-current circuit, and civil power enters reduction voltage circuit, and in reduction voltage circuit, the source electrode of power MOS pipe Q1 exports DC low-voltage V2, and DC low-voltage V2 enters constant-current circuit, exports constant current, and driving LED is luminous:

Reduction voltage circuit comprises comparator LM339 and power MOS pipe Q1, diode D1, D2, D5, D6 forms rectifier bridge B1, the ac input end of rectifier bridge B1 connects synchronous sine wave signal, its direct current output plus terminal connecting resistance R3, its direct current exports negative terminal connecting resistance R4, resistance R3 and resistance R4 connects, its intermediate point connects the inverting input of comparator LM339, the positive pole connecting resistance R1 of DC voltage V1, its negative pole connecting resistance R5, resistance R1 and resistance R5 connects, its intermediate point connects the in-phase input end of comparator LM339, the positive pole of one termination DC voltage V1 of resistance R2 and the positive power source terminal of comparator LM339, the signal output part of its another termination comparator LM339, connect the grid of power MOS pipe Q1 simultaneously, diode D5, the positive pole of D6, the negative pole of DC voltage V1, the negative power end ground connection of comparator LM339, diode D3, D4, D7, D8 form rectifier bridge B2, the ac input end of rectifier bridge B2 meets civil power V3, and its direct current output plus terminal connects the drain electrode of power MOS pipe Q1, and its direct current exports negative terminal and connects power MOS pipe Q1 source electrode by resistance R6, ground connection simultaneously, electric capacity C1 is in parallel with resistance R6,

Constant-current circuit comprises power MOS pipe Q1, Q2 and transformer TX1, the minus earth of DC low-voltage V2, and its positive pole connects the drain electrode of power MOS pipe Q1, Q2 by the former limit of transformer TX1; Diode D9, D10, D11, D12 form rectifier bridge B3, the ac input end of rectifier bridge B3 connects the secondary of transformer TX1, connect the parallel branch that electric capacity C3 and resistance R2 forms simultaneously, its direct current output plus terminal connects the positive pole of electric capacity C4, C5, simultaneously connecting resistance R5, and its direct current exports the negative pole of negative termination capacitor C4, connect the positive pole of DC low-voltage V2 simultaneously, resistance R5 and resistance R13 connects, and intermediate point connects the positive pole of the diode part of optocoupler 4N33 by resistance R6, the other end ground connection of resistance R13; The negative pole of the diode part of optocoupler 4N33 is by resistance R11 ground connection, the emitter stage of its triode part is by resistance R10 ground connection, the colelctor electrode of its triode part connects power Vcc by resistance R1, simultaneously by electric capacity C10 and Zener diode D5 ground connection, the plus earth of Zener diode D5, the minus earth of electric capacity C5, the pin INV of control chip UC1825 connects the emitter stage of the triode part of optocoupler 4N33, pin OUT-A connects the grid of power MOS pipe Q2, and pin OUT-B connects the grid of power MOS pipe Q1.

Accompanying drawing explanation

Fig. 1 is light emitting diode characteristic curve;

Fig. 2 is the relation curve of luminous efficiency and temperature;

Fig. 3 is the schematic circuit of Micro Energy Lose LED illumination power supply;

Fig. 4 is the simulation waveform of each point voltage of schematic circuit of Micro Energy Lose LED illumination power supply;

Fig. 5 is the simulation waveform of gate drive voltage

Fig. 6 is the simulation waveform of load resistance R1, R2 upper output voltage Vp, Vn;

Fig. 7 is the symmetrical output circuit of direct current;

Fig. 8 is the simulation waveform of symmetrical VD;

Fig. 9 is transformer output circuit;

Figure 10 is each point voltage simulation waveform of transformer circuit;

Figure 11 is drive signal generation circuit;

Figure 12 is the simulation waveform of drive singal;

Figure 13 is transformerless output circuit (reduction voltage circuit);

Figure 14 is the simulation waveform of step-down voltage

Figure 15 is symmetrical drive signal generation circuit

Figure 16 is the drive singal simulation waveform of Vc after commutation

Figure 17 is the two-way output circuit of transless

Figure 18 is output voltage simulation waveform

Figure 19 is transformer output circuit

Figure 20 is each point voltage simulation waveform

Figure 21, Figure 22 are the details of unidirectional and two-way output voltage simulation waveform

Figure 21 is the spike simulation waveform details that the steamed bun ripple after rectification cuts down;

Figure 22 is the spike simulation waveform details cut down from sine wave

Figure 23 is constant-current circuit

Figure 25 is the side circuit that constant current produces

Figure 24 is the simulation waveform of constant-current circuit output current

Micro Energy Lose LED illumination power supply make use of the sine voltage (near trough) in minimum interval near alternating voltage zero-crossing just, suitably selects the pulsewidth of metal-oxide-semiconductor drive singal, goes for how low voltage, how lowly just can have.When selecting drive singal pulsewidth 0.5ms, output symmetrical voltage is about 30V, and this voltage also can obtain direct-flow positive voltage after rectification.

Fig. 5 is gate drive voltage V2, V3, V4, V5, simulation waveform, Fig. 6 is the simulation waveform of load resistance R1, R2 upper output voltage Vp, Vn.V2, V3, V4, V5 are interval selection pulses, can see, strobe pulse and the interval one_to_one corresponding of output voltage tip.

Alternately, with the forward output voltage one_to_one corresponding that resistance R5 produces, under left figure transverse axis, part signal V4, V5 are also alternately, with the negative sense output voltage one_to_one corresponding produced on resistance R5 for left figure transverse axis upper part signal V2, V3.

Fig. 7 is the symmetrical output circuit of direct current, and two source electrodes of Q1, Q2 in Fig. 3 circuit, it separates, and uses bulky capacitor in parallel with R5, R6 simultaneously.Then on resistance R5, R6, obtain symmetrical DC voltage, Fig. 8 is its simulation waveform.

This circuit all reduces except 90% except cost, volume, weight, power consumption, and safe and reliable, and can obtain and input ac power auxiliary DC power supply altogether, this point is very important to many application simultaneously.

Fig. 9 is transformer output circuit, circuit connecting and Fig. 3 slightly difference: V2, V3 are the square-wave signals of frequency 50Hz, forward pulsewidth 1ms, time delay 0ms and 9ms respectively, 0ms and the 9ms moment of the positive half cycle of civil power, Q2 saturation conduction, V1 forms loop by the drain-source pole of diode, Q2 in the body of former limit P1, Q1 of transformer TX1 with ground, direct impulse electric current is formed at transformer primary side, pass through magnetic induction, at the electric current that TX1 secondary also forming frequency is identical, form rectifier bridge by D1-D4, become VD Vo.

V4, V5 are the square-wave signals of frequency 50Hz, negative sense pulsewidth 1ms, time delay 10ms and 19ms respectively, 10ms and the 19ms moment of civil power negative half period, Q1 saturation conduction, V1 forms loop with ground, at transformer primary side formation negative-going pulse electric current by the drain-source pole of diode, Q1 in the body of former limit P1, Q2 of transformer TX1, pass through magnetic induction, at the electric current that TX1 secondary also forming frequency is identical, form rectifier bridge by D1-D4, become VD Vo.

By the adjustment no-load voltage ratio of TX1 and the pulsewidth of V2, V3, V4, V5, the amplitude of adjustable output voltage Vo, transformer exports the place that can be used on necessary voltage isolation.Due to the pulse that TX1 former limit input voltage is positive negative direction, do not have dc component in former limit, the voltage waveform that secondary is formed is symmetric double sideband voltage, can adopt bridge rectifier.

Because the input voltage frequency of transformer TX1 is 50Hz, in power conversion, all devices are all operated in power frequency, do not produce high-frequency loss and EMI in disturbing; Input voltage due to transformer TX1 is spike, and TX1 can adopt pulse transformer again, can reduce cost and volume further; Input voltage due to transformer TX1 is Symmetrical pulse, can utilize 4 quadrants of magnetic core magnetization curve, can reduce power consumption and volume further.

Figure 10 is each point voltage simulation waveform of transformer circuit, output voltage Vo, transformer secondary voltage Vs respectively, can see, transformer secondary peak voltage is after magnetic coupling, form series of bilateral band harmonization component, after bridge rectifier filtering, define dc source as shown in simulation waveform.

The side circuit of Micro Energy Lose LED illumination power supply includes drive signal generation circuit, commutating circuit, symmetrical output circuit, transformerless circuit, has transformer circuit, constant current produces is circuit etc., is described in detail as follows:

Figure 11 is drive signal generation circuit, civil power sine voltage V2 is after the whole bridge that D1-D4 forms, steamed bun wave voltage is through resistance R1, R4 dividing potential drop, be added in the end of oppisite phase of comparator U1, DC voltage V1 is added in the in-phase end of comparator U1 through resistance R1, R5 dividing potential drop, the size of suitable regulation voltage R1, can regulate the DC voltage height being added to comparator in-phase end, according to performance and the feature of comparator, the height of this DC voltage determines the pulsewidth exporting direct impulse Va.

Be forward steamed bun ripple owing to being added in U1 end of oppisite phase, so at sinusoidal wave zero passage place, originally negative pulse occurs local, now all above transverse axis, namely in the twice that the pulsewidth of each pulse is original.

Figure 12 is the simulation waveform of drive singal, forms the pulse of twice pulsewidth in the front and back of zero crossing (N × 10ms), Here it is interval selection pulse Vc, selects sinusoidal wave difference interval, minizone before and after the sinusoidal wave zero passage place of this example selection.

Figure 13 is transformerless output circuit (reduction voltage circuit), drive singal (interval selection pulse) Vc that Figure 11 produces, be added in the grid of Q1, the source electrode connecting resistance R6 of Q1, its drain electrode adds the steamed bun wave voltage after civil power V3 rectification, whenever civil power zero passage place, drive singal Vc is high level, Q1 conducting, and steamed bun ripple forms spike voltage by the drain-source pole of Q1 on R6, after drive singal Vc, Q1 ends.

Figure 14 is the simulation waveform of reduction voltage circuit, before and after zero crossing (N × 10ms), form spike output voltage, the amplitude of this pulse voltage is directly proportional to the pulsewidth of drive singal Vc, and the pulsewidth of Vc is directly proportional to the DC voltage being added in Fig. 6 comparator U1 in-phase end, because this DC voltage is adjustable, so the amplitude producing spike output voltage is also adjustable.

As the symmetry output DC voltage of Fig. 7, the bulky capacitor filtering of spike output voltage, can obtain the DC voltage Vo of different amplitude.The DC voltage obtained by transformerless output circuit (reduction voltage circuit), not through pwm power conversion, all devices are all operated in power frequency, and do not produce high-frequency loss and EMI interference, efficiency is close to 100%, and power factor is 1 or is greater than 1.Power factor is greater than 1 and can be regarded as: this circuit not only guarantees that own power factor is 1, and can also improve the power factor of other Sneak Circuits, two kinds of factors are added up, and power factor can be recognized for being greater than 1 simultaneously.

Figure 15 is symmetrical drive signal generation circuit, the commutating circuit (being actually a kind of square wave inverter circuit) of Q1-Q4 composition, unidirectional drive signal Vc is converted to two-way driving and advises signal Vcc, wherein V2, V3, V5, V6 are the square-wave signals of cycle 20ms, pulsewidth 1ms, V3, V5 time delay 10ms.

During front 10ms, Q1, Q4 conducting, unidirectional drive signal Vc, by the drain-source pole of Q1, Q4, is 2 forward burst pulses of 10ms before formation at resistance R4; During rear 10ms, Q2, Q3 conducting, unidirectional drive signal Vc, by the drain-source pole of Q2, Q3, is 2 the negative sense burst pulses forming rear 10ms at resistance R4; Just define positive and negative four burst pulses of one-period altogether.

Figure 16 is the drive singal simulation waveform of Vc after commutation, and 4 the positive and negative burst pulses formed in each cycle, define a series of positive and negative drive singal Vcc.

Figure 17 is the two-way output circuit of transless, the positive and negative drive singal Vcc formed by commutating circuit is added between the grid of Q3, Q4 and source electrode, V4 is input civil power, when the positive half cycle of civil power, drive singal are timing, Q4 conducting, civil power during corresponding with drive singal forms loop by diode, the drain-source pole of Q4, R5 in Q3 body, the positive spike voltage that generation two is corresponding with drive singal on R5; When civil power negative half period, drive singal are for time negative, Q3 conducting, the civil power during corresponding with drive singal forms loop by diode, the drain-source pole of Q3, R5 in Q4 body, the negative spike voltage that generation two is corresponding with drive singal on R5; After one cycle, the positive and negative spike voltage that generation four is corresponding with drive singal on R5, after this reciprocation cycle, produces a succession of positive and negative spike voltage.

Figure 18 is output voltage simulation waveform, spike output voltage and drive singal Vcc one_to_one corresponding, and this voltage strengthens capacitor filtering, can obtain symmetrical bidirectional DC voltage (simulation waveform as Fig. 4).

Figure 19 is transformer output circuit, removes the resistance R5 in Figure 17, and namely increase transformer TX1 and rectification circuit thereof are Figure 19, Q3, Q4 conducting opportunity and current direction, identical with upper figure, no longer repeat.It should be noted that, what flow through in transformer TX1 is Symmetrical electric current, and magnetic core, in magnetic history, does not have remanent magnetism, four quadrants of magnetization curve can be utilized simultaneously, need not degaussing circuit, secondary can adopt bridge rectifier, and circuit is simple and reliable, electric energy loss is little, and efficiency is high, safe and reliable.

Figure 20 is each point voltage simulation waveform, and be topmost export DC voltage Vo, centre is driving voltage Vcc, here is transformer secondary voltage Vs, secondary voltage Vs is double-side band pulse voltage, directly uses bridge circuit rectification, and former limit need not degaussing circuit and DCR circuit.

Figure 21, Figure 22 are the details of unidirectional and two-way output voltage simulation waveform, Figure 21 is the spike voltage waveform that the steamed bun ripple after rectification cuts down, Figure 22 is the spike voltage waveform cut down from sine wave, and its amplitude is decided by the width of drive singal.

Detailed description of the invention

Figure 23 is constant-current circuit, if output-current rating is Io=20A, V2 is input direct voltage, is namely the DC voltage Vo adopting Figure 13, Figure 19 circuit to obtain.Control chip UC1825 exports two-way complementary drive signals OUT-A, OUT-B, the break-make of control Q1, Q2, resistance R3, R11 produce pulsating current, DC current is formed after electric capacity C3 filtering, UC1825 is by the voltage on chip 4N33 sense resistance R11, and the electric current I o namely in perception R3, R11 branch road, when this electric current is greater than rated current 20A, UC1825 adjusts the output pulse width of narrow OUT-A, OUT-B, recovers output current 20A; When this electric current is less than rated current 20A, UC1825 adjusts the output pulse width of wide OUT-A, OUT-B, recovers output current 20A.That is to say, no matter load is how many, and portion can make output current keep rated value 20A, reaches the effect of constant current output.

Figure 24 is the simulation waveform of constant-current circuit output current, and output current is 20A, and no matter load changes or input voltage change, and output current all can keep constant.

Figure 25 is the side circuit that constant current produces, and compared with Figure 23, the DC voltage Vc that the secondary of TX1 produces is superimposed upon on input voltage Vi, forms Vh=Vi+Vc, produces continuous current by Vh.

The principle producing constant current is identical with Figure 13 circuit with process, no longer repeats herein.The essence of constant current output is: output current is constant, such as 5A, and output voltage is variable, such as changes to 100V from 80V, and at this moment load resistance will change to 20 Ω from 16 Ω.Output voltage Va in this circuit is set as 80V, meet the situation of least load 16 Ω, bucking voltage Vc is set as 20V, Vh=Va+Vc=80+20=100V, meet the situation of maximum load 20 Ω, when load resistance changes between 16 Ω to 20 Ω, voltage changes between 80V-100V, and output current is constant, keep constant.

Because voltage Va=80V directly obtains from input voltage, do not participate in actual power conversion, there is no power attenuation, this part efficiency can regard 100% as, only have Vc=20V will obtain from power conversion, if this part conversion efficiency is 85%, then conversion is exactly 97% (calculating is omitted) to the efficiency of complete machine

This circuit all reduces except 90% except cost, body weight, power consumption, and safe and reliable, and can obtain and input ac power auxiliary DC power supply altogether, this point is very important to many application simultaneously.

1) high-frequency loss is not had, because main device is operated in power frequency.

2) operating voltage waveform is impulse wave, need not Industrial Frequency Transformer.

3) for the sine wave of input, only get the very small portion voltage closest to zero, in fact do not draw input power.

4) export DC voltage efficiency close to 100%, power factor is close or be greater than 1.

Claims (1)

1. a Micro Energy Lose LED illumination power supply, it is characterized in that Micro Energy Lose LED illumination power supply is made up of reduction voltage circuit and constant-current circuit, civil power enters reduction voltage circuit, in reduction voltage circuit, the source electrode of power MOS pipe Q1 exports DC low-voltage V2, DC low-voltage V2 enters constant-current circuit, export constant current, driving LED is luminous:

1) reduction voltage circuit comprises comparator LM339 and power MOS pipe Q1, first, two, five, six diode (D1, D2, D5, D6) rectifier bridge B1 is formed, the ac input end of rectifier bridge B1 connects synchronous sine wave signal, its direct current output plus terminal connects the 3rd resistance (R3), its direct current exports negative terminal and connects the 4th resistance (R4), 3rd resistance (R3) and the series connection of the 4th resistance (R4), its intermediate point connects the inverting input of comparator LM339, the positive pole of DC voltage V1 connects the first resistance (R1), its negative pole connects the 5th resistance (R5), first resistance (R1) and the series connection of the 5th resistance (R5), its intermediate point connects the in-phase input end of comparator LM339, the positive pole of one termination DC voltage V1 of the second resistance (R2) and the positive power source terminal of comparator LM339, the signal output part of its another termination comparator LM339, connect the grid of power MOS pipe Q1 simultaneously, 5th, six diode (D5, D6) positive pole, the negative pole of DC voltage V1, the negative power end ground connection of comparator LM339, third and fourth, seven, eight diodes (D3, D4, D7, D8) form rectifier bridge B2, the ac input end of rectifier bridge B2 meets civil power V3, its direct current output plus terminal connects the drain electrode of power MOS pipe Q1, its direct current exports negative terminal and connects power MOS pipe Q1 source electrode by the 6th resistance (R6), ground connection simultaneously, electric capacity C1 is in parallel with the 6th resistance (R6),

2) constant-current circuit comprises first and second power MOS pipe (Q1, Q2) and transformer TX1, the minus earth of DC low-voltage V2, and its positive pole connects the drain electrode of first and second power MOS pipe (Q1, Q2) by the former limit of transformer TX1, 9th, ten, 11, 12 diode (D9, D10, D11, D12) rectifier bridge B3 is formed, the ac input end of rectifier bridge B3 connects the secondary of transformer TX1, connect the parallel branch that the 3rd electric capacity (C3) and the second resistance (R2) form simultaneously, its direct current output plus terminal connects the 4th, five electric capacity (C4, C5) positive pole, connect the 5th resistance (R5) simultaneously, its direct current exports the negative pole that negative terminal connects the 4th electric capacity (C4), connect the positive pole of DC low-voltage V2 simultaneously, 5th resistance (R5) and the series connection of the 13 resistance (R13), intermediate point connects the positive pole of the diode part of optocoupler 4N33 by the 6th resistance (R6), the other end ground connection of the 13 resistance (R13), the negative pole of the diode part of optocoupler 4N33 is by the 11 resistance (R11) ground connection, the emitter stage of its triode part is by the tenth resistance (R10) ground connection, the colelctor electrode of its triode part connects power Vcc by the first resistance (R1), simultaneously by the tenth electric capacity (C10) and Zener diode D5 ground connection, the plus earth of Zener diode D5, the minus earth of the 5th electric capacity (C5), the pin INV of control chip UC1825 connects the emitter stage of the triode part of optocoupler 4N33, pin OUT-A connects the grid of the second power MOS pipe (Q2), pin OUT-B connects the grid of the first power MOS pipe (Q1).