CN106505865A - A kind of asymmetrical half-bridge anti exciting converter and its drive control method - Google Patents

Abstract

The invention provides a kind of asymmetrical half-bridge anti exciting converter and its drive control method, the load signal that asymmetrical half-bridge anti exciting converter is detected by load detecting circuit, which is compared with the load point for setting, and comparative result is formed feedback signal and exported to drive control module and Master control chip simultaneously；To drive circuit, drive circuit exports two paths of signals, i.e. main switch drive signal and drive voltage signal to Master control chip output pwm signal, and main switch drive signal drives turning on and off for main switch, and drive voltage signal is input to drive control module；After drive control module receives drive voltage signal and feedback signal, export the first drive signal or the second drive signal to control the turn-on and turn-off of clamp switch pipe.Control method of the present invention and control circuit is simple and reliable, easy realization, can solve the problems, such as asymmetrical half-bridge anti exciting converter the light load of output and unloaded when be lost big, improve light load efficiency.

Description

A kind of asymmetrical half-bridge anti exciting converter and its drive control method

Technical field

The present invention relates to a kind of asymmetrical half-bridge anti exciting converter and its drive control method.

Background technology

As the fast development of field of power electronics, the application of switch converters are more and more extensive, particularly people are to height The switch converters of power density, high reliability and small size propose more requirements.Typically traditional small power switch becomes Parallel operation realizes that using flyback topologies which has the advantages that simple structure, with low cost；But common flyback topologies are hard switchings, And leakage inductance energy can not be reclaimed, therefore limit the efficiency and volume of middle low power changer.In order to meet power inverter Miniaturization, lightweight, modular development trend, soft switch technique have become one of focus of Power Electronic Technique." soft open Close " refer to zero voltage switching or zero current switching, it is to utilize resonance principle, make switch converters switch tube voltage (or electricity Stream) by sinusoidal (or quasi sine) rule change, when voltage zero-cross, opening device (or during electric current natural zero-crossing, closes device Disconnected), realize that switching loss is zero, so as to improve efficiency and the switching frequency of changer, reduce transformator, the volume of inductance.Though So, soft switch technique can realize the miniaturization of power inverter, modularity etc., but, a lot of circuits such as LLC, circuit become Extremely complex so that the cost of the changer of middle low power increases, and is often unfavorable for commercial competition.And asymmetry half-bridge circuit exists With the number of devices and complexity of common circuit of reversed excitation relatively under conditions of can realize that the no-voltage of two switching tubes is opened Logical, leakage inductance energy is reclaimed, and easily realizes self-device synchronous rectification, reduce transformation body while effective raising efficiency Product, becomes a reasonable application scheme.

At present the circuit diagram of conventional asymmetrical half-bridge anti exciting converter is as shown in Fig. 1-1 and 1-2, in wherein Fig. 1-1 on Pipe QH is main switch, and down tube QL is clamp switch pipe；In Fig. 1-2, upper pipe QH is clamp switch pipe, and down tube QL is main switch, Two kinds of circuit operation principles are essentially identical, and simply winding position is different.

By taking Fig. 1-1 as an example, as shown in Fig. 2-1, VgsH and VgsL is respectively upper pipe QH and down tube to the work wave of its stable state The drive voltage signal waveform of QL；Ic is the current waveform for flowing through resonant capacitance Cr, while being also to flow through transformer primary side winding Current waveform；ILm is the exciting curent waveform for flowing through magnetizing inductance Lm, in addition to dotted portion, exciting curent waveform and The current waveform of resonant capacitance is consistent coincidence；VdsH and VdsL is respectively the electricity of the drain-to-source of upper pipe QH and down tube QL Pressure signal waveform.The dutycycle of the drive signal VgsH of hypothesis supervisor QH is D, then the duty of the drive signal VgsL of clamper tube QL Than for (1-D), common for avoiding being responsible for QH and clamper tube QL, need to leave certain Dead Time；Switch periods are Ts；Transformation The primary side winding of device can be equivalent to leakage inductance Lr and magnetizing inductance Lm two parts.

This control mode is complementary because of the drive voltage signal of upper and lower switching tube, even go up switching tube (or be referred to as on Pipe) drive voltage signal VgsH dutycycle be D, then descend the dutycycle of switching tube (or referred to as down tube) drive voltage signal VgsL For (1-D), the ratio of ON time and switch periods Ts of dutycycle D of pipe drive voltage signal VgsH equal to upper pipe is wherein gone up, Transformer excitation electric current ILm is a continuous waveform；Again as dutycycle D of upper pipe does not become with the change of load Change, and changer light load and unloaded when, transformator need to only transmit little energy and can achieve output voltage to outfan Stablize, but during underloading down tube ON time almost unchanged compared with the ON time of full load, then resonant capacitance Cr is under Manage in whole ON time to transformator degaussing, this demagnetization process can be equivalent to a fictitious load and persistently consume excitatory energy Amount, therefore in underloading and zero load, transformer primary side peak point current still can be very big, and substantial amounts of energy is disappeared in resonant tank Consumption, causes loss of the changer when gently loading to greatly increase, greatly reduces light-load efficiency and increased no-load power consumption.Herein Described underloading (or light load) refers to less than 50% load；No-load power consumption as herein described refers to that the outfan of changer is empty The power consumption of its input during load.

Existing another kind of control method is improved for above-mentioned control mode：With the circuit shown in Fig. 1-1 it is still Example, when the output loading of asymmetrical half-bridge anti exciting converter is heavier, control asymmetrical half-bridge anti exciting converter enters complementary work Operation mode, this complementary working mode are the first drive signal complementary by two and the second drive signal control main switch The mode of operation of (or supervisor) and clamp switch pipe (or clamper tube), i.e. the dutycycle of the first drive signal driving main switch is Value D, then it is value (1-D), the steady operation of this complementary working mode that the second drive signal drives the dutycycle of clamp switch pipe Waveform is as shown in Fig. 2-1；When the output loading of asymmetrical half-bridge anti exciting converter is lighter, then control asymmetrical half-bridge flyback becomes Parallel operation enters incomplementarity mode of operation, and this kind of incomplementarity mode of operation is by two non-complementary 3rd drive signals and 4 wheel driven Dynamic signal control main switch and the mode of operation of clamp switch pipe, i.e. the 3rd drive signal drive pincers with a fixed pulse width signal The shut-off of bit switch pipe, fourth drive signal with the fixed pulse width of one the 3rd drive signal of time delay and a Dead Time when The fixed pulse width signal produced after length drives the shut-off of main switch, turns off in main switch and it is not opened by clamp switch pipe Before, the energy of the leakage inductance of transformator and magnetizing inductance forms leakage through the body diode or junction capacity of clamp switch pipe and main switch Sense resonant tank and transformer resonance loop, until clamp switch pipe is again turned on, resonance terminates, then restarts new week Phase, as shown in Fig. 2-2, existing this control method can be to a certain degree for the steady operation waveform of this incomplementarity mode of operation Upper reduction partial unloading power consumption and raising light load efficiency, but there are the following problems：(1) because of transformation in main switch turn on process Device is excitatory and energy storage, in clamp switch pipe turn on process transformator to secondary transmission energy, and when gently loading, main switch and pincers The ON time of bit switch pipe all immobilizes, and the dutycycle of main switch is a fixed value, then when input voltage or defeated When going out load change, the output voltage of changer can change therewith or even cannot realize voltage stabilizing.For example, if input voltage is raised, Then transformer primary side exciting curent increase, transformator energy storage increase；Then in clamp switch pipe turn on process, to maintain weber to put down Weighing apparatus, transformator necessarily increase to the energy that secondary is transmitted, and cause output voltage to raise；(2) when gently loading, after main switch shut-off Transformer primary side magnetizing inductance Lm is refracted to voltage (NVo) clamp of former limit by transformer secondary, is turned off very in main switch In long a period of time, clamp switch pipe is open-minded not yet, then transformer primary side leakage inductance Lr, resonant capacitance Cr can pass through clamp switch pipe The body diode of QL carries out resonance, and as shown in t1～t2 time periods in Fig. 2-2, resonant energy is in two pole of body of clamp switch pipe QL Consume in pipe, cause loss increase, efficiency to reduce；(3), during changer output underloading, main switch is turned off and clamp switch pipe In a very long time also not turned on, because transformer primary side leakage inductance Lr can with resonant capacitance Cr or with upper and lower two switching tubes Junction capacity carry out resonance, cause exciting curent ILm with resonance current Ic and unequal, so as to cause secondary side diode long-time Conducting, as shown in t1～t3 time periods in Fig. 2-2, energy is consumed in secondary side diode so that underloading loss increases；(4) become When parallel operation output loading is lighter or unloaded, main switch shut-off and a very long time that clamp switch pipe is not yet turned on Interior, transformer primary side exciting curent ILm declines, and causes transformer primary side leakage inductance Lr and resonant capacitance Cr to pass through clamp switch pipe QL Body diode or the body diode of main switch QH be circulated resonance, body diode of the energy in upper and lower two switching tubes Middle consumption so that no-load power consumption is still larger.

So, for the distinct disadvantage that above-mentioned asymmetrical half-bridge anti exciting converter and its control method are present, this patent is sent out A person of good sense is analysed in depth to asymmetrical half-bridge anti exciting converter, and thus the present invention produces.

Content of the invention

In view of this, the invention solves the problems that above-mentioned asymmetrical half-bridge anti exciting converter is lost in the light load of output and zero load A kind of big problem, there is provided the drive control of loss of reduction asymmetrical half-bridge anti exciting converter in the light load of output and zero load Method and asymmetrical half-bridge anti exciting converter, the asymmetrical half-bridge anti exciting converter circuit structure are simple, output voltage when unloaded Ripple is little, easily realize with practical.

First purpose of the present invention, is to provide a kind of drive control method of asymmetrical half-bridge anti exciting converter, including Following steps：

Judge the load signal of asymmetrical half-bridge anti exciting converter whether less than the load point for setting；

If it is, ON time of the clamped switching tube in each switch periods is reduced by drive control module, and The ON time of control clamp switch pipe reduces with the mitigation of the output loading of asymmetrical half-bridge anti exciting converter, and with not right Claim the increase of the output loading of half bridge flyback changer and increase so that the ON time of main switch is also with asymmetrical half-bridge The mitigation of the output loading of anti exciting converter and reduce, and increase with the increase of the output loading of asymmetrical half-bridge anti exciting converter Greatly；Main switch and clamp switch pipe is made to be operated in incomplementarity mode of operation, described incomplementarity refers to main switch and clamped The dutycycle sum of the drive voltage signal of switching tube is not equal to 1；

If it is not, then by drive control module, make main switch and clamp switch pipe work in complementary working mode, Described complementation refers to that the dutycycle sum of the drive voltage signal of main switch and clamped switching tube is equal to 1.

Two paths of signals as referred to herein is complementary：Refer to that the dutycycle sum of two paths of signals is equal to 1；Two paths of signals is not complementary： Refer to that the dutycycle sum of two paths of signals is not equal to 1, if hereinafter to mention complementation or incomplementarity, no longer individually explained.

The principle of the self-feedback adjustment effect of circuit is：In light load, asymmetrical half-bridge anti exciting converter is detected Output loading less than the load point for setting when, reduce ON time of the clamp switch pipe in each switch periods, and control The ON time of clamp switch pipe processed reduces with the mitigation of asymmetrical half-bridge anti exciting converter output loading, with asymmetrical half-bridge The increase of anti exciting converter output loading and increase；Under this kind of light load mode, because asymmetrical half-bridge anti exciting converter is only needed Little energy is transmitted to regulated output voltage by outfan, after the ON time of clamp switch pipe reduces, changer is used Constant in the energy transmitted needed for regulated output voltage, but resonant capacitance Cr is greatly reduced to the degaussing time of transformator, resonance The excitatory energy that electric capacity Cr is consumed also is greatly reduced, and therefore the excitatory energy needed for power circuit is just reduced, and main switch is excitatory Time reduces, i.e., the ON time of main switch reduces；When the output loading of asymmetrical half-bridge anti exciting converter increases, clamp The ON time increase of switching tube, resonant capacitance Cr increased to the degaussing time of transformator, were to maintain stablizing for output voltage, became The excitatory energy of depressor and excitatory time also necessarily increase, then the ON time increase of main switch.So, in light load not The ON time of the main switch of symmetrical half bridge anti exciting converter is also with the output loading of asymmetrical half-bridge anti exciting converter Increase and increase, and reduce with the mitigation of the output loading of asymmetrical half-bridge anti exciting converter.Thus, then working as asymmetrical half-bridge When anti exciting converter works in light load, the ON time of main switch and clamp switch pipe is all less and works in incomplementarity mould Formula, prevents energy to be consumed in resonant tank, to reduce damage of the asymmetrical half-bridge anti exciting converter in gently load and zero load Consumption.

Another kind of improved though of control method of the present invention is：When detecting asymmetrical half-bridge anti exciting converter work Make in, during underloading (when the output loading of asymmetrical half-bridge anti exciting converter is less than the load point for setting), to open clamp is reduced While closing ON time of the pipe in each switch periods, reduce the operating frequency of asymmetrical half-bridge anti exciting converter, to enter One step reduces loss of the asymmetrical half-bridge anti exciting converter in gently load and zero load.Principle is：During underloading, reduce clamp switch The ON time TwL of pipe can effectively reduce the loss of asymmetrical half-bridge anti exciting converter, also, TwL is less, the loss of changer Less；But the ON time TwL of clamp switch pipe can not possibly be infinitely small, and TwL once reaches the limit of value, and circuit loss also reaches pole Limit value, now, by reducing the operating frequency of changer, can reduce peak value and the virtual value of transformer primary side exciting curent, and The operating magnetic field flux density of magnetic core of transformer can be reduced, this allow for the copper loss of transformator and magnetic loss, the switching loss of switching tube and Drive loss all further reduces, so as to further improving the light-load efficiency of asymmetrical half-bridge anti exciting converter and reducing unloaded work( Consumption.

Preferably, the method for operating frequency for reducing asymmetrical half-bridge anti exciting converter is, Master control chip is using having Reduce the IC of the function of operating frequency during underloading.

Preferably, the method for reducing the operating frequency of asymmetrical half-bridge anti exciting converter is, negative by peripheral circuit detection The change of load is so as to reducing the operating frequency of Master control chip.

Second object of the present invention, be to provide a kind of can reduce underloading and unloaded when loss asymmetrical half-bridge anti- Exciting converter, described asymmetrical half-bridge anti exciting converter include circuit of reversed excitation, described circuit of reversed excitation include main switch and Clamp switch pipe, it is characterised in that：Described asymmetrical half-bridge anti exciting converter also includes detecting control circuit, described detection Control circuit includes Master control chip, drive circuit, drive control module and load detecting circuit；Load detecting circuit is detected not Whether the output loading of symmetrical half bridge anti exciting converter, compare the output loading signal of asymmetrical half-bridge anti exciting converter less than setting Fixed load point, and feedback signal is exported simultaneously to drive control module and Master control chip；Master control chip output PWM letters Number give drive circuit, drive circuit export two paths of signals, i.e. main switch drive signal and drive voltage signal, main switch drive Dynamic signal drives turning on and off for main switch, and drive voltage signal is input to drive control module；Drive control module connects After receiving drive voltage signal and feedback signal, export the first drive signal or the second drive signal to control clamp switch pipe Turn-on and turn-off.

Described Master control chip includes that the application condition inside VCC feet, pwm signal output pin, Master control chip is put The output pin and GND feet of big device；VCC feet are used for connecting power supply, and GND feet connect input ground, and pwm signal output pin is used for Output pwm signal, the output pin of the application condition amplifier inside Master control chip connect the outfan of load detecting circuit Feedback signal.

Described drive circuit includes PWM input pins, the first output pin and the second output pin, the work of drive circuit With being：After PWM input pins receive pwm signal, through conversion, defeated by the first output pin and the second output pin respectively Go out main switch drive signal and drive voltage signal, described main switch drive signal and the complete phase of described pwm signal With described drive voltage signal is complementary with pwm signal.

Described drive control module includes first comparator, the second comparator, first resistor, second resistance, the 3rd electricity Resistance, the first diode, the second diode, the 3rd diode, the 4th diode, the first electric capacity, the first metal-oxide-semiconductor；First resistor First pin connects the second outfan of drive circuit, and the second pin of first resistor connects the first pin of the first electric capacity, the The second pin connection input ground of one electric capacity；First pin of the first electric capacity be also connected with simultaneously the anode of the first diode, second First pin of resistance and the input in the same direction of first comparator；Second output of the negative electrode connection drive circuit of the first diode End；The second pin of second resistance connects the negative electrode of the second diode, and the anode of the second diode connects the defeated of first comparator Go out end；Meanwhile, the outfan of first comparator is also connected with the grid of the first metal-oxide-semiconductor, and the source electrode connection of the first metal-oxide-semiconductor is input into ground, First pin of the leakage connection 3rd resistor of the first metal-oxide-semiconductor, while be also connected with the anode of the 4th diode；The second of 3rd resistor Pin connects the negative electrode of the 4th diode, while being additionally coupled to the second outfan of drive circuit；Second comparator reverse defeated Enter the output pin of the application condition amplifier inside end connection Master control chip, the in-phase input end linker of the second comparator Quasi- voltage；The reverse input end of first comparator is also connected to the reverse input end of the second comparator, the output of first comparator The anode of the 3rd diode of end connection, the negative electrode of the 3rd diode are connected to the outfan of the second comparator；The leakage of the first metal-oxide-semiconductor Outfan of the pole as drive control module, the control voltage signal output first according to the outfan of first comparator drive letter Number or the second drive signal, to drive turning on and off for clamp switch pipe.

Preferably, described drive control module include the first current-limiting resistance, the second current-limiting resistance, the first audion, One Zener diode, the first charging diode, the first diode, the second diode, first comparator, second resistance, the 3rd electricity Resistance and the 4th diode；First pin of the first described current-limiting resistance, the first pin of the second current-limiting resistance, the first diode Negative electrode be connected simultaneously to the second outfan of drive circuit, the second pin of the first current-limiting resistance connects the base of the first audion Pole and the negative electrode of the first Zener diode, the anode of the first Zener diode connect input ground；The second pin of the second current-limiting resistance Connect the colelctor electrode of the first audion；The emitter stage of the first audion connects the anode of the first charging diode, the first charging two The negative electrode of pole pipe connects the first pin of the first electric capacity, the second pin connection input ground of the first electric capacity；The first of first electric capacity Pin is also connected with the first pin of the anode of the first diode, the input in the same direction of first comparator U1 and second resistance, and second The second pin of resistance connects the negative electrode of the second diode, and the anode of the second diode connects the outfan of first comparator；With When, the outfan of first comparator is additionally coupled to the grid of the first metal-oxide-semiconductor, and the source electrode of the first metal-oxide-semiconductor connects with being input into, and first First pin and the anode of the 4th diode of the drain electrode connection 3rd resistor of metal-oxide-semiconductor；The second pin of 3rd resistor and the 4th The negative electrode of diode is connected to the second outfan of drive circuit；In the reverse input end connection Master control chip of first comparator The output pin of the application condition amplifier in portion；Outfan of the drain electrode of the first metal-oxide-semiconductor as drive control module, according to first The control voltage signal of comparator output exports the first drive signal or the second drive signal, to drive the conducting of clamp switch pipe With shut-off.

Preferably, described drive control module include first comparator, the second comparator, the second electric capacity, the 4th resistance, 5th resistance, second resistance, the second diode, the 4th current-limiting resistance, the 5th current-limiting resistance, the 3rd audion and the five or two pole Pipe, the second electric capacity and the 4th resistance constitute peaker, and the 5th resistance, second resistance and the second diode constitute positive and negative feed Road, the 4th current-limiting resistance, the 5th current-limiting resistance and the 3rd audion constitute level shifting circuit；The first of 4th current-limiting resistance is drawn The output pin and the reverse input end of the second comparator of the application condition amplifier inside foot connection Master control chip, the 4th limit The second pin of leakage resistance connects the base stage of the 3rd audion；The input connection reference voltage in the same direction of the second comparator, second The outfan of comparator connects the negative electrode of the 5th diode；The emitter stage of the 3rd audion connects input ground, the collection of the 3rd audion Electrode is simultaneously connected with the reverse input end of the second pin, the anode of the 5th diode and first comparator of the 5th current-limiting resistance； The first pin connection power supply VCC of the 5th current-limiting resistance；The second of the first pin connection drive circuit of the second electric capacity is defeated Go out end, the second pin of the second electric capacity connects the first pin of first pin and the 5th resistance of the 4th resistance；4th resistance Second pin connects input ground；5th resistance second pin connection second resistance the first pin and first comparator in the same direction defeated Enter end；The second pin of second resistance connects the negative electrode of the second diode, the anode connection first comparator of the second diode Outfan, the outfan of first comparator export the first drive signal or second and drive as the outfan of drive control module Signal, to drive turning on and off for clamp switch pipe.

Further, the second described comparator is replaced with a transistor control circuit, and described audion is controlled Circuit includes the first divider resistance, the second divider resistance, the second audion and the 3rd current-limiting resistance；Mistake inside Master control chip The output pin of difference comparison amplifier, the second pin of the first divider resistance be simultaneously connected with the second pin of the second divider resistance and The base stage of the second audion, the emitter stage of first pin and the second audion of the second divider resistance connect jointly and are input into ground, and second The colelctor electrode of audion connects the second pin of the 3rd current-limiting resistance, and the colelctor electrode of the second audion is also connected with the 3rd diode Negative electrode or the negative electrode of the 5th diode, the first pin of the 3rd current-limiting resistance meet power supply VCC.

Preferably, increase a driving IC between the outfan of described drive control module and clamp switch pipe, described Driving IC the described drive control module of input connection outfan, the outfan of described drivings IC connects clamp and opens The grid of pipe is closed, to drive the conducting and shut-off of clamp switch pipe, the output voltage of described driving IC is according to described driving The change of the voltage of the outfan of control module and change, can more quickly drive clamp switch pipe, strengthen whole detection The driving force of control circuit.

A kind of operation principle of described asymmetrical half-bridge anti exciting converter is：When described load detecting circuit is detected When the output loading of described asymmetrical half-bridge anti exciting converter is higher than the load point for setting, load detecting circuit exports feedback letter Number to described drive control module, make described drive control module export the first drive signal VgsL1 and be given to clamp switch Pipe, to drive the conducting and shut-off of clamp switch pipe, and makes the first described drive signal VgsL1 and main switch drive signal VgsH is complementary；

Set when the output loading that described load detecting circuit detects described asymmetrical half-bridge anti exciting converter is less than During fixed load point, load detecting circuit output feedback signal to described drive control module makes described drive control mould Block exports the second drive signal VgsL2 and is given to clamp switch pipe, to drive the conducting and shut-off of clamp switch pipe, and makes described Second drive signal VgsL2 and main switch drive signal VgsH incomplementarities；If also, the asymmetrical half-bridge anti exciting converter Output loading mitigate, then the pulse width and dutycycle of the second drive signal VgsL2 reduces therewith；If the asymmetrical half-bridge The output loading of anti exciting converter increases, then the pulse width and dutycycle of the second drive signal VgsL2 increases therewith, that is, clamp The ON time of switching tube reduces with the mitigation of the output loading of the asymmetrical half-bridge anti exciting converter, and with described not right Claim the increase of the output loading of half bridge flyback changer and increase；Accordingly, the ON time of main switch is also with asymmetric half The mitigation of the output loading of bridge anti exciting converter and reduce, and the increasing of the output loading with the asymmetrical half-bridge anti exciting converter Plus and increase.

Compared with prior art, a kind of asymmetrical half-bridge anti exciting converter of the invention and its drive control method have as follows Beneficial effect：

(1) no-load power consumption of asymmetrical half-bridge anti exciting converter is reduced, light load efficiency is improve；

(2) the magnetic core transmission energy of transformator can be maximally utilised when heavy duty, improve asymmetric half The efficiency of the whole machine of bridge anti exciting converter；

(3) control method and control circuit is simple and reliable, easy realization.

Description of the drawings

Fig. 1-1 (goes up pipe QH for main switch, down tube QL is for the circuit theory diagrams of existing asymmetrical half-bridge anti exciting converter Clamp switch pipe)；

Fig. 1-2 is that the circuit theory diagrams of existing asymmetrical half-bridge anti exciting converter (go up pipe QH for clamp switch pipe, down tube QL For main switch)；

Fig. 2-1 (goes up pipe QH for main switch, down tube QL for the steady operation waveform of existing asymmetrical half-bridge anti exciting converter For clamp switch pipe)；

For the steady operation waveform of existing incomplementarity mode of operation asymmetrical half-bridge anti exciting converter, (upper pipe QH is Fig. 2-2 Main switch, down tube QL are clamp switch pipe)；

Fig. 3-1 is a kind of schematic block circuit diagram of asymmetrical half-bridge anti exciting converter first embodiment of the present invention；

Fig. 3-2 is a kind of circuit theory diagrams of asymmetrical half-bridge anti exciting converter first embodiment of the present invention；

Fig. 3-3 is each in a kind of asymmetrical half-bridge anti exciting converter first embodiment drive control module of the present invention The steady operation waveform of key node；

Fig. 3-4 works in stable state work during incomplementarity pattern for a kind of asymmetrical half-bridge anti exciting converter of the present invention Make waveform；

Fig. 4 is that the technology receives the circuit connection diagram in middle comparator practical application；

Fig. 5 is a kind of circuit theory diagrams of asymmetrical half-bridge anti exciting converter second embodiment of the present invention；

Fig. 6-1 is a kind of circuit theory diagrams of asymmetrical half-bridge anti exciting converter 3rd embodiment of the present invention；

Fig. 6-2 is a kind of circuit theory diagrams of asymmetrical half-bridge anti exciting converter fourth embodiment of the present invention；

Fig. 6-3 is a kind of circuit theory diagrams of the 5th embodiment of asymmetrical half-bridge anti exciting converter of the present invention；

Fig. 7-1 is a kind of circuit theory diagrams of asymmetrical half-bridge anti exciting converter sixth embodiment of the present invention；

Fig. 7-2 is a kind of circuit theory diagrams of the 7th embodiment of asymmetrical half-bridge anti exciting converter of the present invention；

Fig. 7-3 is each in a kind of the 7th embodiment drive control module of asymmetrical half-bridge anti exciting converter of the present invention The steady operation waveform of key node.

Specific embodiment

For a better understanding of the present invention, specific embodiment is set forth below to be illustrated.

First embodiment

Fig. 3-1 shows the schematic block circuit diagram of the asymmetrical half-bridge anti exciting converter of first embodiment of the invention, Fig. 3-2 Circuit theory diagrams for first embodiment of the invention.Asymmetrical half-bridge anti exciting converter includes circuit of reversed excitation and detection control electricity Road；Circuit of reversed excitation includes primary circuit and secondary output rectifier and filter.Primary circuit is by filter capacitor Cin, resonant capacitance The primary side winding of Cr, main switch QH, clamp switch pipe QL and transformator T is formed by connecting, leakages of the Lr for transformator T primary side windings Sense；One end of Cin is connected to input positive pole Vin+, and the other end is connected to input ground GND (or input negative pole), main switch QH's Drain electrode connection Vin+, source electrode connect the drain electrode of clamp switch pipe QL, the grid connection main switch drive signal of QH；The source electrode of QL Connection GND, the drive signal of the grid connecting detection control circuit output of QL；One end of resonant capacitance Cr is connected to the source electrode of QH With the drain electrode of QL, the other end of Cr is connected to the Same Name of Ends of the primary side winding of transformator T, the different name termination of transformer primary side winding GND；Secondary output rectifier and filter is formed by connecting by commutation diode D, filter capacitor Cout；

The different name end of the anode connection transformer T vice-side windings of D, the negative electrode of D meet transformator output cathode Vo+, transformator T The Same Name of Ends connection output negative pole Vo- of vice-side winding；One end connection Vo+ of filter capacitor Cout, other end connection transformer pair Side output negative pole Vo-；Vo+ is also the output cathode of asymmetrical half-bridge anti exciting converter simultaneously, and Vo- is also asymmetrical half-bridge simultaneously The output negative pole of anti exciting converter.

Detection control circuit includes Master control chip, drive circuit, load detecting circuit, drive control module；Described Master control chip is put including the application condition inside VCC feet, pwm signal output pin, Master control chip using IC LM5021 The output pin and GND feet of big device；VCC is the energization pins for controlling IC LM5021, and Comp is IC LM5021 internal error ratios Compared with the outfan of amplifier, reflect the change of changer output voltage, the application condition amplifier inside Master control chip defeated Go out pin voltage Vcomp to increase with the increase of asymmetrical half-bridge anti exciting converter output loading, and with asymmetrical half-bridge flyback The mitigation of changer output loading and reduce；Output pin of the pwm signal output pin for IC LM5021 drive signals, this draws Foot output pwm signal Vgs is given to drive circuit.

Described drive circuit adopts IC Si8234, the OUT terminal output pwm signal Vgs of LM5021 to be given to Si8234's PWM pins, are changed by IC Si8234 internal circuits, and by VOA pins (i.e. the first output pin) and VOB pins, (i.e. second is defeated Go out pin) output two-way drive signal, i.e. main switch drive signal VgsH and drive voltage signal VgsL, wherein, VgsH with Pwm signal Vgs is identical, and VgsL and pwm signal Vgs is complementary；Main switch drive signal VgsH drives main switch QH, After voltage drive signals VgsL are driven voltage control conversion by drive control module, exported by the drain electrode of N-MOS pipes First drive signal VgsL1 or the second drive signal VgsL2 is used for driving clamp switch pipe QL.

Described drive control module includes comparator U1, comparator U2, charging resistor R1, resistance R2, resistance Rd, electric discharge Diode D1, diode D2, diode D3, discharge diode Dd, charging capacitor C1, N-MOS pipe Q1；Drive voltage signal VgsL First pin of connection charging resistor R1, the second pin of charging resistor R1 connect first pin of charging capacitor C1, and charge electricity Hold the second pin connection input negative pole GND (i.e. input ground) of C1；First pin of charging capacitor C1 is also connected with discharge diode The anode of D1, the negative electrode of discharge diode D1 connect first pin of resistance R1, while being also connected with drive voltage signal VgsL； The second pin of charging resistor R1 is also connected with the input in the same direction of comparator U1, and the in-phase input end of comparator U1 is also connected with resistance First pin of R2, the second pin of resistance R2 connect the negative electrode of diode D2, the anode connection comparator U1's of diode D2 Outfan；Meanwhile, the outfan of comparator U1 is also connected with the grid of N-MOS pipe Q1, and the source electrode connection of N-MOS pipe Q1 is input into ground, First pin of the leakage connection resistance Rd of N-MOS pipe Q1, while be also connected with the anode of discharge diode Dd；The second of resistance Rd is drawn Foot connects the negative electrode of discharge diode Dd, while being additionally coupled to drive voltage signal VgsL；Inside Master control chip IC LM5021 Application condition amplifier output pin (i.e. Comp) connect comparator U1 reverse input end, while being also connected with comparator U2 Reverse input end, be compared with reference voltage V ref for being connected to comparator U2 in-phase input ends, the output of comparator U1 End is connected to the outfan of comparator U2 by a diode D3, and wherein, the anode connection comparator U1's of diode D3 is defeated Go out end, the negative electrode of diode D3 connects the outfan of comparator U2；The drain electrode of N-MOS pipe Q1 is according to the outfan of comparator U1 Control voltage signal exports the first drive signal VgsL1 or the second drive signal VgsL2, and exports and give clamp switch pipe QL, with Drive the conducting and shut-off of QL.

The input of described load detecting circuit connects the outfan of asymmetrical half-bridge anti exciting converter, load detecting electricity Road includes optocoupler OC1, sampling resistor Rf1, sampling resistor Rf2, resistance R21, electric capacity C21, resistance R10, electric capacity C10 and adjustable steady Depressor TL431；One end of Rf1 is connected to the output cathode Vo+ of asymmetrical half-bridge anti exciting converter, and the other end of Rf1 is with Rf2's One end is connected, another termination output negative pole Vo- of Rf2；One end connection Vo+ of R21, the other end of R21 are connected to optocoupler OC1's 1st pin (i.e. the anode of the light emitting diode inside optocoupler OC1), the 2nd pin of optocoupler OC1 are (i.e. luminous inside optocoupler OC1 The negative electrode of diode) it is connected to the negative pole of TL431, (i.e. phototriode inside optocoupler OC1 is sent out for the 3rd pin of optocoupler OC1 Emitter-base bandgap grading) connect the one end for being input into ground GND and C10, the 4th pin (i.e. the colelctor electrode of the phototriode inside optocoupler OC1) of optocoupler Comp pin and the input of drive control module of the output feedback signal Vcomp to Master control chip；One end connection light of R10 4th pin of coupling, the other end connect the other end of C10；The adjustable end of TL431 is connected to the series connection node of Rf1 and Rf2, TL431 Positive pole meet Vo-；One end of C21 connects the negative pole of TL431, and the other end of C21 connects the adjustable end of TL431.

The effect of load detecting circuit be detect asymmetrical half-bridge anti exciting converter output loading, and by load signal with The load point of setting is compared, and comparative result formation feedback signal is exported to drive control module and Master control chip. Load detecting circuit is not limited to above-described annexation, and in prior art, any one can realize the load inspection of the function Slowdown monitoring circuit can.

It should be noted that：Typically, comparator is all colelctor electrode or open-drain output, in actual use, comparator In addition to needing normal power supply and ground connection, in addition it is also necessary to export one pull-up resistor of termination to power supply at which, for being compared Transistor inside device provides voltage and current loop so that comparator normal work, and connects pull-up resistor and can improve and compare Device exports load-carrying ability, as shown in figure 4, this is the common knowledge of this area.Comparator in all of accompanying drawing of the present invention, All give tacit consent to and increased power supply and earth-return circuit, and increased pull-up resistor, be intended merely to simplify accompanying drawing, do not draw, not generation The all of comparator of table, or cannot work because connecting power supply not over pull-up resistor because of not power supply and earth-return circuit Make.

The present invention control method be：

Whether the output loading of load detecting circuit detection asymmetrical half-bridge anti exciting converter is less than the load point for setting；

If it is, i.e. asymmetrical half-bridge anti exciting converter works in light-load mode, then by drive control module, open master Close pipe QH and clamp switch pipe QL and work in complementary working mode, and the ON time of clamp switch pipe QL is controlled with asymmetric half The mitigation of bridge anti exciting converter output loading and reduce, and increase with the increase of asymmetrical half-bridge anti exciting converter output loading Greatly；Due to the self-feedback adjustment effect of circuit so that the ON time of main switch QH becomes also with asymmetrical half-bridge flyback The mitigation of parallel operation output loading and reduce, and increase with the increase of asymmetrical half-bridge anti exciting converter output loading；

If it is not, i.e. asymmetrical half-bridge anti exciting converter works in non-light-load mode, then by drive control module, make Main switch QH and clamp switch pipe QL work in complementary working mode.

When the output loading of described asymmetrical half-bridge anti exciting converter is underloading, asymmetrical half-bridge anti exciting converter work Make in incomplementarity mode of operation, while reduce the operating frequency of asymmetrical half-bridge anti exciting converter, asymmetric further to reduce Loss of the half bridge flyback changer in underloading；

The method for reducing the operating frequency of asymmetrical half-bridge anti exciting converter is that Master control chip is using drop when there is underloading The IC of the function of low operating frequency；

The method for reducing the operating frequency of asymmetrical half-bridge anti exciting converter can also be, by peripheral circuit detection load Change and adjust control IC operating frequency.

The circuit operation principle of first embodiment of the invention is specific as follows：

Setting reference voltage V ref works in corresponding when setting load point equal to asymmetrical half-bridge anti exciting converter The magnitude of voltage of Comp feet, then：

(1) when the output loading of asymmetrical half-bridge anti exciting converter is more than the load point for setting, the Comp of main control IC Voltage Vcomp is of a relatively high for foot, i.e. Vcomp ＞ Vref, then comparator U2 outputs low level, the output end voltage quilt of comparator U1 Clamp to the conduction voltage drop VD3 of diode D3, general VD3 is about 0.7V, then N-MOS pipes Q1 is held off, drive voltage signal VgsL exports the first drive signal VgsL1 by resistance Rd and diode Dd to drive clamp switch pipe QL, VgsL1 to follow driving Voltage signal VgsL, and complementary with main switch drive signal VgsH, then and main switch and clamp switch pipe work in complementary work Operation mode；The effect of diode Dd is, when VgsL is converted to low level by high level, makes the drain voltage of N-MOS pipe Q1 (i.e. First drive signal VgsL1) released to zero rapidly by diode Dd, to accelerate the shut-off of QL, reduce turn-off power loss；

(2) when the output loading of asymmetrical half-bridge anti exciting converter is less than the load point for setting, the Comp of main control IC Voltage Vcomp is relatively low for foot, i.e. Vcomp ＜ Vref, then comparator U2 outputs high level, and comparator U1 and comparator U2 is used Identical power voltage supply, no matter the voltage of comparator U1 outfans for height or is low, and diode D3 ends because reverse-biased；This When, the second drive signal VgsL passes through charging resistor R1 and discharge diode D1 to electric capacity C1 discharge and recharges, and electric capacity C1 two ends The voltage Vcomp of voltage Vc1 and IC LM5021 the first pin Comp feet be compared, i.e., when VgsL exports high level, lead to Cross resistance R1 to charge electric capacity C1, when the voltage Vc1 at C1 two ends is charged to higher than Vcomp, comparator U1 exports high level, Turn on N-MOS pipes Q1, the drain electrode output low level of N-MOS pipes just achieves the shut-off in advance of QL, its ON time and reduces Purpose；When VgsL is converted to low level by high level, the voltage Vc1 at electric capacity C1 two ends is discharged to by diode D1 rapidly Zero, and Vcomp all the time both greater than zero, so comparator U1 output low levels, N-MOS pipes Q1 is turned off, the drain electrode of N-MOS pipe Q1 with Low level is exported with VgsL；When next switch periods arrive, and VgsL is high level by low transition, because of delaying for electric capacity C1 Punching act on, still less than Vcomp, comparator U1 still exports low level to Vc1, N-MOS pipe Q1 still in off state, so N-MOS The drain voltage of pipe Q1 follows VgsL to be output as high level, once electric capacity C1 both end voltages Vc1 are charged to higher than Vcomp, N- Metal-oxide-semiconductor Q1 is turned on, and the drain voltage of N-MOS pipe Q1 is pulled low to close to zero rapidly, that is, is achieved the shut-off in advance of QL. And under this light-load mode, because of the self-feedback adjustment effect of circuit, the ON time of QH will necessarily be with the ON time of QL Reduction and reduce, and QH shut-off after after the Dead Time of a nanosecond, QL is open-minded immediately, so just makes asymmetric Half bridge flyback changer enters incomplementarity mode of operation in light load, and now the drain voltage signal of N-MOS pipes Q1 is the Two driving signal VgsL2；Additionally, when the output loading of asymmetrical half-bridge anti exciting converter changes, controlling the Comp feet electricity of IC Pressure Vcomp also can change therewith, and when the output loading of asymmetrical half-bridge anti exciting converter increases, Vcomp is raised, electric capacity C1 two The voltage needs at end are charged to higher voltage and can just make comparator U1 output high level so that N-MOS pipes Q1 conductings, compare The time of device U1 output high level reduces, then the time increase of the drain electrode output high level of N-MOS pipes Q1, the second drive signal The high level lasting time of VgsL2 increases, i.e. the ON time of QL increases；Conversely, defeated when asymmetrical half-bridge anti exciting converter When going out load reduction, Vcomp reduces, and the voltage at electric capacity C1 two ends is only needed to be charged to lower voltage and can just make comparator U1 Output high level is so that N-MOS pipes Q1 conductings, the time increase of comparator U1 output high level, then the drain electrode of N-MOS pipes Q1 is defeated The time for going out high level is reduced, and the high level lasting time of the second drive signal VgsL2 is reduced, i.e. the ON time of QL reduces； When so just achieving light load, in asymmetrical half-bridge anti exciting converter, the ON time of clamp switch pipe QL reduces, and with not right Claim half bridge flyback changer output loading increase and increase, and with asymmetrical half-bridge anti exciting converter output loading mitigation and Reduce.

In first embodiment of the invention, as shown in Fig. 3-3, wherein, VgsL is the logical signal waveform of each key node of circuit The drive voltage signal of the VOB pins output of ICSi8234, when asymmetrical half-bridge anti exciting converter works in complementary working mode When, the first drive signal VgsL1 is completely the same with drive voltage signal VgsL, and complementary with main switch drive signal VgsH； Voltages of the Vc1 for electric capacity C1 two ends, voltages of the Vcomp for main control IC Comp ends, voltages of the Vu1 for comparator U1 outfans (and grid voltage of N-MOS pipe Q1).

Fig. 3-4 works in stable state during incomplementarity pattern for asymmetrical half-bridge anti exciting converter in first embodiment of the invention Work wave, wherein, ILm for transformer primary side magnetizing inductance electric current, Ic be flow through resonant capacitance Cr electric current (also referred to as humorous Shake electric current), while being also the electric current for flowing through transformer primary side leakage inductance Lr；The waveform of ILm in addition to dotted portion, remainder with humorous The waveform of electric current Ic of shaking is completely superposed；VdsH for QH drain electrode and source electrode between voltage, VdsL for QL drain electrode and source electrode it Between voltage.When the output loading of asymmetrical half-bridge anti exciting converter is less than load point (the i.e. asymmetrical half-bridge flyback change for setting The output loading of parallel operation is underloading) when, the driving voltage of QL is VgsL2 (the second drives i.e. described in first embodiment of the invention Dynamic signal), now because of the self-feedback adjustment effect of circuit, the driving voltage incomplementarity of the driving voltage of QH and QL just can have Effect reduce asymmetrical half-bridge anti exciting converter underloading and unloaded when because of resonant tank in the loss that causes of energy circulation, improve light Load efficiency；And work as the output loading of asymmetrical half-bridge anti exciting converter higher than load point (the i.e. asymmetrical half-bridge flyback for setting The output loading of changer is not underloading) when, changer is entered in complementary working mode, and QH and QL is with maximum duty cycle work Make, magnetic core of transformer is operable with bigger magnetic flux density, and changer just can maximally utilise magnetic core transmission energy so that Overall efficiency is improved；Also, this underloading incomplementarity control mode is simply easily realized, reality by the ON time of QL need to be only controlled Show significantly improving for light load efficiency, and make circuit reliably work.

What deserves to be explained is, for asymmetrical half-bridge anti exciting converter, control method of the present invention and existing control method There are many differences, be described as follows：

(1) when existing control method is to detect asymmetrical half-bridge anti exciting converter to work in underloading, main switch The ON time of ON time and clamp switch pipe all immobilizes, i.e., drive clamp switch pipe with a fixed pulse width signal Open and shut-off, and another signal is with the fixed pulse width of one clamp switch pipe drive signal of time delay and a Dead Time The fixed pulse width signal produced after duration drives opening and shut-off for main switch；And the control method of the present invention is, detect When asymmetrical half-bridge anti exciting converter works in underloading, reduce ON time of the clamp switch pipe in each switch periods, and And the ON time of clamp switch pipe reduces with the mitigation of asymmetrical half-bridge anti exciting converter output loading, and with asymmetric half The increase of bridge anti exciting converter output loading and increase；Under light load mode of the present invention, because of asymmetrical half-bridge anti exciting converter Only need to transmit little energy to regulated output voltage by outfan, if the output loading of changer is same load point, Then after the ON time of clamp switch pipe QL reduces, the energy that changer is used for transmission needed for regulated output voltage is constant, but Resonant capacitance was greatly reduced to the degaussing time of transformator, and the excitatory energy that resonant capacitance Cr is consumed also is greatly reduced, therefore work( Excitatory energy needed for rate circuit is just reduced, and the main switch QH excitatory times reduce, i.e. the ON time of main switch QH reduces； When the output loading of asymmetrical half-bridge anti exciting converter increases, the ON time increase of clamp switch pipe QL, resonant capacitance Cr The degaussing time of transformator is increased, is to maintain stablizing for output voltage, the excitatory energy of transformator and excitatory time also inevitable Increase, then the ON time increase of main switch QH.

(2), when existing control method is to detect asymmetrical half-bridge anti exciting converter to work in underloading, main switch is closed Disconnected and clamp switch pipe has a very long time before not turning on, in this section of long time, the leakage inductance of transformator and excitatory The energy of inductance forms leakage inductance resonant tank through the body diode or junction capacity of clamp switch pipe and main switch and transformator is humorous Shake loop, until clamper tube is again turned on, resonance terminates, then restarts the new cycle；And the control method of the present invention is, main Switching tube shut-off only leaves the Dead Time of nanosecond with clamp switch pipe before turning on, the Dead Time is opened only for preventing master Close pipe and clamp switch pipe is common, and it is turned on reserved main switch shut-off under complementary working mode with clamp switch pipe Front Dead Time is identical.

(3) existing control method is when detecting asymmetrical half-bridge anti exciting converter and working in underloading, because of main switch ON time and the ON time of clamp switch pipe all immobilize, when input voltage changes or output loading changes, defeated Go out voltage to stablize, i.e., voltage regulation factor and load regulation are excessively poor；And the control method of the present invention is being detected not When symmetrical half bridge anti exciting converter works in underloading, the ON time of only control clamp switch pipe increases with the increase of output loading Greatly, and with the mitigation of output loading reduce, the ON time of main switch is voluntarily adjusted to meet output voltage by circuit Stable.

(4) existing control method is when detecting asymmetrical half-bridge anti exciting converter and working in underloading, in main switch In some time that shut-off and clamp switch pipe are not turned on, because leakage inductance and resonant capacitance resonance make the body diode of clamp switch pipe Long-time is turned on；And when resonant energy is larger, leakage inductance can equally make the body diode of main switch with resonant capacitance resonance Conducting, this results in resonant energy and consumes in the body diode of upper and lower switching tube, increases loss；Meanwhile, in main switch In some time that shut-off and clamp switch pipe are not turned on, secondary side diode is constantly in conducting state so that loss significantly increases Plus；And the control method of the present invention is when detecting asymmetrical half-bridge anti exciting converter and working in underloading, main switch shut-off with The interval time that clamp switch pipe is not turned on is only the Dead Time of nanosecond, the achievable clamp switch pipe of this Dead Time ZVS (no-voltage is open-minded), resonant energy will not be consumed in the body diode of main switch or clamp switch pipe in a large number, secondary Diode also will not be turned on for a long time, and this all greatly reduces loss.

(5) existing control method when detecting asymmetrical half-bridge anti exciting converter and working in underloading, only controls master and opens The ON time for closing the ON time and clamp switch pipe of pipe all immobilizes, and the operating frequency of changer does not change；And this The another embodiment of invention is, when detecting asymmetrical half-bridge anti exciting converter and working in underloading, except reducing clamp The ON time of switching tube, and the ON time of clamp switch pipe is controlled with the output loading of asymmetrical half-bridge anti exciting converter Increase and increase, and reduce with the mitigation of the output loading of asymmetrical half-bridge anti exciting converter, additionally reduce asymmetric half The operating frequency of bridge anti exciting converter, further to reduce loss of the asymmetrical half-bridge anti exciting converter in underloading and zero load.

Second embodiment

As shown in figure 5, for the circuit theory diagrams of asymmetrical half-bridge anti exciting converter second embodiment of the present invention, empty 502 part of wire frame is drive control module.

Compared with first embodiment of the invention, the difference of second embodiment is, in the drain output of N-MOS pipes A driving IC2 is increased and the grid of clamp switch pipe QL between, in order to more rapidly to drive clamp switch pipe QL, is driven The input of IC2 connects the drain electrode of N-MOS pipe Q1, the grid for driving the outfan of IC2 to connect QL, drives the outfan electricity of IC2 Pressure follows the change of input terminal voltage；After through the IC2 that overdrives, the driving force of whole detection control circuit is enhanced, this Bright second embodiment is essentially identical with the operation principle of first embodiment, will not be described here.

Now using the circuit topology in Fig. 5 in the embodiment, make sample and tested.

In order to the beneficial effect of the asymmetrical half-bridge anti exciting converter of second embodiment of the invention is described, with showing for comparing The asymmetrical half-bridge anti exciting converter sample for having technology employs identical circuit parameter：Including transformator T, transformator T is by magnetic Core and corresponding coil windings two parts composition, coil windings include primary side winding Np, vice-side winding Ns and assists winding Nf, auxiliary Winding is helped to be used as accessory power supply, in order to power to main control IC, driving IC1, driving IC2 and comparator；Coil windings are spread by PCB After copper, etching is formed, i.e., transformator T does flat surface transformer known to cost professional field；Magnetic core uses EIR20 magnetic cores；Transformator The number of turns of each winding is respectively Np=5, Ns=8, Nf=2；Main switch QH and clamp switch pipe QL are managed using N-MOS；Output Commutation diode uses Schottky diode；Output filter circuit is filtered using Pi (π) type；Master control chip is using with underloading The IC of frequency-dropping function.

The drive control method of the present invention is not used to no-load power consumption to the asymmetrical half-bridge anti exciting converter of above-mentioned parameter When being optimized with light load efficiency, the no-load power consumption actual measurement such as table 2- of the asymmetrical half-bridge anti exciting converter sample of prior art Shown in 1, light load efficiency is surveyed as shown in table 2-2.

Table 2-1

Table 2-2

Circuit theory diagrams shown in second embodiment of the invention are used to above-mentioned asymmetrical half-bridge anti exciting converter sample, such as Shown in Fig. 5, wherein, reference voltage V ref is obtained by accessory power supply and electric resistance partial pressure, and sets Vref=2.17V；Drive IC2 Using IC LM5114B, drive circuit is using driving IC1Si8234.The no-load power consumption of actual measurement and the data of corresponding switching frequency As shown in table 3, the light load efficiency of actual measurement and corresponding switching frequency data are as shown in table 4.

Table 3

Table 4

140. changer input voltages：110VDC.

Contrast test data from table 3 this it appears that：(1) when the operating frequency of asymmetrical half-bridge anti exciting converter Constant, when being 150KHz, then using underloading incomplementarity control model asymmetrical half-bridge anti exciting converter second embodiment of the present invention Drive control method and detection control circuit, during underloading control asymmetrical half-bridge anti exciting converter work in incomplementarity Working mould Formula, reduces the ON time of QL, then the no-load power consumption of changer is considerably decreased to 3.08W by 17.8W, reduces 4.78 times； (2) reduce the ON time of QL, and reduce switching frequency of the asymmetrical half-bridge anti exciting converter in underloading, 110VDC During input, when making the unloaded switching frequency of asymmetrical half-bridge anti exciting converter be reduced to 90KHz by 303KHz, the zero load of changer Power consumption is considerably decreased to 1.10W by 9.08W, reduces 7.2 times.

Contrast test data from table 4 are, it is apparent that when 110VDC is input into, the asymmetrical half-bridge of the present invention is anti- Efficiency of the exciting converter in 25% and following load is all significantly increased.

It will be apparent that the drive using second embodiment of the invention underloading incomplementarity control model asymmetrical half-bridge anti exciting converter Flowing control method and detection control circuit, can significantly reduce loss of the asymmetrical half-bridge anti exciting converter in underloading and zero load, Improve light load efficiency.

3rd embodiment

As in Figure 6-1, be asymmetrical half-bridge anti exciting converter 3rd embodiment of the present invention circuit theory diagrams, 601 part of dotted line frame is detection control circuit.

From drive control module part unlike first embodiment, the VOB pins of IC1 in the third embodiment, are driven First pin of outputting drive voltage signal VgsL, VgsL the first current-limiting resistance R11 of connection, the second of the first current-limiting resistance R11 Pin connects the base stage of charging audion TR1, while being also connected with the negative electrode of Zener diode Z1, the anode of Zener diode Z1 connects Input ground GND (i.e. the input negative pole of asymmetrical half-bridge anti exciting converter)；Drive voltage signal VgsL is also connected with the second current limliting electricity First pin of resistance R12, the second pin of the second current-limiting resistance R12 connect the colelctor electrode of charging audion TR1；Charging audion The emitter stage of TR1 connects the anode of charging diode D11, and the first of the negative electrode connection charging capacitor C1 of charging diode D11 draws Foot, the second pin connection input negative pole GND of charging capacitor C1；First pin of charging capacitor C1 is also simultaneously connected with two poles of electric discharge The input in the same direction of the anode of pipe D1, first pin of resistance R2 and comparator U1；The negative electrode connection second of discharge diode D1 First pin of current-limiting resistance R12, while be also connected with drive voltage signal VgsL；The in-phase input end connection electricity of comparator U1 First pin of resistance R2, the second pin of resistance R2 connect the negative electrode of diode D2, the anode connection comparator U1 of diode D2 Outfan；Meanwhile, the outfan of comparator U1 is additionally coupled to the grid of N-MOS pipe Q1, the source electrode connection input of N-MOS pipe Q1 First pin of the drain electrode connection resistance Rd of ground GND, N-MOS pipe Q1, while be also connected with the anode of discharge diode Dd；Resistance Rd Second pin connect discharge diode Dd negative electrode, while being additionally coupled to drive voltage signal VgsL；Inside Master control chip Application condition amplifier output pin (i.e. the Comp pins of IC LM5021) connect comparator U1 reverse input end；N- Outfan of the drain electrode of metal-oxide-semiconductor Q1 as drive control module, according to the control voltage signal output of the outfan of comparator U1 First drive signal VgsL1 or the second drive signal VgsL2, and export to QL, to drive the conducting and shut-off of QL.

It should be noted that by the resistance for adjusting the first current-limiting resistance R11 and the second current-limiting resistance R12, making charging three Pole pipe TR1 works in magnifying state；Charging capacitor C1 chooses suitable capacitance, to guarantee that charging voltage Vc1 at C1 two ends will not Too high, as long as guaranteeing the main control IC when the output loading of asymmetrical half-bridge anti exciting converter is more than the load point for setting More than the maximum Vc1max of Vc1, Comp foot magnitudes of voltage Vcomp just can ensure that changer works in complementation in non-light condition Mode of operation.

The concrete operating principle of the asymmetrical half-bridge anti exciting converter of third embodiment of the invention is as follows：

(1) when the output loading of asymmetrical half-bridge anti exciting converter is more than the load point for setting, the Comp of main control IC Voltage Vcomp is of a relatively high for foot, because having ensured that during design that the maximum Vc1max of voltage at electric capacity C1 two ends is less than asymmetric half Comp foot magnitude of voltage Vcomp of the output loading of bridge anti exciting converter more than main control IC during the load point for setting, therefore comparator U1 exports low level, and N-MOS pipe Q1 are held off, then drive voltage signal VgsL directly drives QL by resistance Rd, i.e., now The drain electrode of N-MOS pipe Q1 exports the first drive signal VgsL1 and drives QL, and the first drive signal VgsL1 follows driving voltage to believe The change of number VgsL, and completely the same with VgsL, now drive voltage signal VgsL1 of drive voltage signal VgsH of QH and QL Complementary；

(2) when the output loading of asymmetrical half-bridge anti exciting converter is less than the load point for setting, the Comp of main control IC Voltage Vcomp is relatively low for foot；Now, drive voltage signal VgsL that drive circuit (driving IC1) is exported is limited by first Leakage resistance R11, the second current-limiting resistance R12, charging audion TR1, charging diode D11 and discharge diode D1 are filled to electric capacity C1 Electric discharge, and the voltage Vc1 at electric capacity C1 two ends is passed through comparator U1 with the voltage Vcomp of IC LM5021 the first pin Comp feet It is compared；When VgsL exports high level, electric capacity C1 is electrically charged, when the voltage Vc1 at C1 two ends is charged to higher than Vcomp When, comparator U1 exports high level, turns on N-MOS pipes Q1, and the drain voltage of N-MOS pipe Q1 is low level, just achieves QL In advance shut-off, QL ON time reduce purpose；When VgsL is converted to low level by high level, the electricity at electric capacity C1 two ends Pressure Vc1 is released to zero by discharge diode D1 rapidly, and Vcomp is both greater than zero all the time, so comparator U1 output low levels, N-MOS pipes Q1 is turned off, and the drain electrode of N-MOS pipe Q1 follows VgsL output low levels；When next switch periods arrive, VgsL is by low When level conversion is high level, because of the cushioning effect of electric capacity C1, Vc1 still exports low level, N- still less than Vcomp, comparator U1 Metal-oxide-semiconductor Q1 is still in off state, so the drain electrode of N-MOS pipe Q1 follows VgsL output high level, once electric capacity C1 two ends Voltage Vc1 is charged to higher than Vcomp, then N-MOS pipes Q1 is turned on, and the drain voltage of N-MOS pipe Q1 is pulled low to rapidly Close to zero, the shut-off in advance of QL is realized.And under this light-load mode, because of the self-feedback adjustment effect of circuit, QH leads The logical time will necessarily reduce with the reduction of the ON time of QL, and after QH shut-offs after the Dead Time of one section of nanosecond QL is open-minded immediately, so just makes asymmetrical half-bridge anti exciting converter enter incomplementarity mode of operation in light load, now N-MOS The drain voltage signal of pipe Q1 is the second drive signal VgsL2；Additionally, the output loading when asymmetrical half-bridge anti exciting converter During change, the Comp foot voltage Vcomp for controlling IC also can change therewith, when the output loading of asymmetrical half-bridge anti exciting converter increases Added-time, Vcomp raise, and the voltage needs at electric capacity C1 two ends are charged to higher voltage can just make comparator U1 output high level So that N-MOS pipes Q1 conductings, the time minimizing of comparator U1 output high level, the then drain electrode of N-MOS pipes Q1 export high level Time increases, and the high level lasting time of the second drive signal VgsL2 increases, i.e. the ON time of clamp switch pipe QL increases； Conversely, when the output loading of asymmetrical half-bridge anti exciting converter mitigates, Vcomp reduces, the voltage at electric capacity C1 two ends is only needed to Being charged to lower voltage can just make comparator U1 output high level so that N-MOS pipes Q1 conductings, the high electricity of comparator U1 outputs The flat time increases, then the time minimizing of the drain electrode output high level of N-MOS pipes Q1, the high level of the second drive signal VgsL2 Persistent period is reduced, i.e. the ON time of clamp switch pipe QL reduces；When so just achieving light load, asymmetrical half-bridge flyback In changer, the ON time of clamp switch pipe QL reduces, and increases with the increase of asymmetrical half-bridge anti exciting converter output loading Greatly, and with the mitigation of asymmetrical half-bridge anti exciting converter output loading reduce.

Using the drive control method shown in third embodiment of the invention Fig. 6-1 and drive control circuit, can equally show Writing reduces loss and no-load power consumption of the asymmetrical half-bridge anti exciting converter in underloading, improves light load efficiency；And work as asymmetric When the output loading of half bridge flyback changer is not underloading, (i.e. the output loading of asymmetrical half-bridge anti exciting converter is higher than to set During load point), changer is entered in complementary working mode, and main switch and clamp switch pipe are all worked with maximum duty cycle, are become Depressor magnetic core is operable with bigger magnetic flux density, and changer just can maximally utilise magnetic core transmission energy so that whole machine Efficiency is improved；Also, this underloading incomplementarity control model of the invention is simply easily realized, the conducting of clamp switch pipe need to be only controlled Time can achieve significantly improving for light load efficiency, and make circuit reliably work.

Fourth embodiment

Circuit theory diagrams of the Fig. 6-2 for fourth embodiment of the invention, 602 part of dotted line frame are detection control circuit.With figure Shown in 6-1, circuit is compared, and the difference of circuit shown in Fig. 6-2 is, in the grid of the drain output and QL of N-MOS pipe Q1 Between increased one driving IC2, in order to more rapidly drive QL, drive IC2 output end voltage follow drive IC defeated Enter the change of terminal voltage (i.e. the drain voltage of N-MOS pipes Q1), increase and drive IC2 effectively improve whole detection control circuit Driving force.Circuit shown in Fig. 6-2 is essentially identical with the operation principle of circuit shown in Fig. 6-1, will not be described here.

5th embodiment

Circuit theory diagrams of the Fig. 6-3 for fifth embodiment of the invention, 603 part of dotted line frame are detection control circuit.With Fig. 5 The difference of shown embodiment two is that comparator U2 is replaced by audion TR2 control circuits, and audion TR2 is controlled Circuit includes divider resistance R211, divider resistance R22, audion TR2, current-limiting resistance R23；The first pin connection U1's of R211 The second pin connection of the output pin Comp of the application condition amplifier inside reverse input end and Master control chip, R211 The second pin of R22, its junction point are simultaneously connected with the base stage of TR2, and first pin of R22 connects input jointly with the emitter stage of TR2 The second pin of the colelctor electrode connection R23 of ground GND, TR2 and the negative electrode of diode D3, first pin of R23 connect power supply The anode of VCC, D3 connects the outfan of U1.Divider resistance R211 and divider resistance R22 chooses suitable resistance, you can set three poles The real work voltage VBE of pipe TR2 emitter junctions, i.e. the voltage VR22=VBE=Vcomp*R22/ at divider resistance R22 two ends (R211+R22) audion TR2 is controlled according to the change of Comp foot voltage Vcomp, and works in saturation conduction state or cut-off shape State, i.e., when the virtual voltage VBE of TR2 emitter junctions is more than or equal to its emitter junction conducting voltage VBEon, TR2 is turned on；Work as TR2 When the virtual voltage VBE of emitter junction is less than its emitter junction conducting voltage VBEon, TR2 is turned off；The setting of R211, R22 and R23 is needed Guarantee that TR2 can operate at saturation region.

The operation principle of circuit shown in Fig. 6-3 is as follows：When the output loading of asymmetrical half-bridge anti exciting converter is higher than setting Load point when, the Comp foot voltage Vcomp of main control IC are of a relatively high, now VBE=Vcomp*R22/ (R211+R22) ＞ VBEon, audion TR2 saturation conductions, close to zero, the output voltage of comparator U1 passes through diode to the collector voltage of TR2 D3 is clamped to conducting voltage VD3 of diode D3, VD3 ≈ 0.7V, then N-MOS pipes Q1 shut-offs, the drain electrode output of N-MOS pipe Q1 The change of voltage follow drive voltage signal VgsL, and the change of drive voltage signal VgsL is equally followed after the IC2 that overdrives, I.e. now the first drive signal VgsL1 is consistent with drive voltage signal VgsL of drive control module, and drives with main switch Signal VgsH is complementary；When the output loading of asymmetrical half-bridge anti exciting converter is less than the load point for setting, the Comp of IC is controlled Voltage Vcomp is relatively low for foot, now VBE=Vcomp*R22/ (R211+R22) ＜ VBEon, and audion TR2 is turned off, TR2's Collector voltage is high level, and close to power supply VCC, and VCC is powered to comparator U1 simultaneously, so when diode D3 Reverse-biased cut-off, audion TR2 control circuits have no effect on the working condition of N-MOS pipe Q1, now the work of drive control module Pattern is identical with circuit shown in Fig. 5 with operation principle, will not be described here.

Sixth embodiment

Circuit theory diagrams of the Fig. 7-1 for sixth embodiment of the invention, from drive control module portion unlike embodiment one Point, in embodiment six, drive control module includes comparator U1, comparator U2 and diode D31, electric capacity C31 and resistance R31 structures Into peaker, resistance R32, R2 and diode D2 composition positive-feedback circuits, current-limiting resistance R33, R34 and audion TR3 compositions Level shifting circuit；The output pin Comp's and U2 of the application condition amplifier inside one end connection Master control chip of R33 Reverse input end, the other end of R33 connect the base stage of TR3；The input connection reference voltage Vref in the same direction of U2, outfan connect The negative electrode of D31；The emitter stage of TR3 connects input ground, and colelctor electrode is simultaneously connected with the reverse input of one end of R34, the anode of D31 and U1 End；The other end connection power supply VCC of R34；The VgsL signals of one end connection drive circuit output of C31, the other end connect One end of R31 and one end of R32；Another termination input ground of R31；The other end of R32 connects the in the same direction of the 1st pin and U1 of R2 Input；2nd pin of R2 connects the negative electrode of D2, and the anode of D2 connects the outfan of U1, and the outfan output first of U1 drives Signal VgsL1 or the second drive signal VgsL2 signals drive turning on and off for QL to QL.

The value that resistance R33 and R34 are rationally set is needed, makes audion TR3 work in magnifying state, then when Comp feet electricity When pressure Vcomp is raised, the voltage Vc of the colelctor electrode of TR3 reduces；Conversely, when Comp foot voltages Vcomp reduces, the current collection of TR3 The voltage Vc of pole is raised；The voltage VR31 at the voltage V+ and resistance R31 two ends of the in-phase input end of comparator U1 is of substantially equal, i.e., V+≈VR31.The operation principle of the embodiment is：

Setting reference voltage V ref works in corresponding when setting load point equal to asymmetrical half-bridge anti exciting converter The magnitude of voltage of Comp feet, then：

(1) when the output loading of asymmetrical half-bridge anti exciting converter is more than the load point for setting, the Comp of main control IC Voltage Vcomp is of a relatively high for foot, and Vcomp is more than reference voltage V ref for setting, i.e. Vcomp ＞ Vref, then comparator U2 Output low level, the output end voltage of comparator U2 are clamped to the conduction voltage drop VD31 of diode D31, and general VD31 is about 0.7V, then the collector voltage of audion TR3 be clamped to VD31, i.e. now Vc=VD31 ≈ 0.7V；Resistance R31 and electric capacity It is to be more than Vc between high period in VgsL that C31 chooses suitable value and can cause the voltage VR31 at resistance R31 two ends, then comparator U1 is to export high level between high period in VgsL；And VgsL be low period between, because resistance R31 both end voltages be negative, i.e., There are VR31 ＜ Vc (or V+ ＜ Vc), therefore comparator U1 is that low level is exported between low period in VgsL；In this non-light-load mode Under, the output voltage of comparator U1 follows drive voltage signal VgsL, the i.e. output voltage signal of comparator U1 to be first and drives Dynamic signal VgsL1, and complementary with main switch drive signal VgsH, make main switch QH and clamp switch pipe QL work in complementation Mode of operation；

(2) when the output loading of asymmetrical half-bridge anti exciting converter is less than the load point for setting, the Comp of main control IC Voltage Vcomp is relatively low for foot, then the collector voltage Vc of audion TR3 is of a relatively high；Now Comp feet voltage Vcomp is less than Reference voltage V ref of setting, i.e. Vcomp ＜ Vref, then comparator U2 outputs high level, comparator U1 and comparator U2 are used Identical power supply VCC is powered, and diode D31 ends because reverse-biased, therefore the output voltage of comparator U2 has no effect on The working condition of comparator U1；When drive voltage signal VgsL is high level by low transition, because of electric capacity C31 and resistance The differential action of the peaker that R31 is constituted, the voltage VR31 at resistance R31 two ends can follow rapidly VgsL to be risen to by low level High level, subsequently, within time periods of the VgsL for high level, VR31 is slowly reduced by maximum, but is decreased to less than in VR31 Before the collector voltage Vc of audion TR3, i.e. during VR31 ＞ Vc (or V+ ＞ Vc), comparator U1 exports high level；Work as VR31 Vc is decreased to less than, i.e., during VR31 ＜ Vc (or V+ ＜ Vc), comparator U1 exports low level, so just achieves clamp switch pipe The shut-off in advance of QL；And thereafter before VgsL exports high level again, the output voltage of comparator U1 is all low level； When VgsL is high level by low transition again, comparator U1 exports high level therewith, worked before then repeating Journey, in the embodiment, the voltage waveform of each key node is as shown in Fig. 7-3；Under this light-load mode, because circuit self is anti- Feedback adjustment effect, the ON time of main switch QH will necessarily reduce with the reduction of the ON time of clamp switch pipe QL, and And after the Dead Time of one section of nanosecond, clamp switch pipe QL is open-minded immediately after main switch QH shut-offs, it is not right so just to make Half bridge flyback changer is claimed to enter incomplementarity mode of operation in light load, now the voltage signal of the outfan of comparator U1 is For the second drive signal VgsL2；Additionally, when the output loading of asymmetrical half-bridge anti exciting converter changes, main control IC's Comp foot voltage Vcomp also can change therewith, and when the output loading of asymmetrical half-bridge anti exciting converter increases, Vcomp is raised, The collector voltage Vc of audion TR3 reduces, and the voltage VR31 needs at resistance R31 two ends are decreased to lower voltage can just make ratio High level is exported compared with device U1, the time of comparator U1 output high level increases, i.e., the high level of the second drive signal VgsL2 continues Time increases, and the ON time of clamp switch pipe QL increases；Conversely, when the output loading of asymmetrical half-bridge anti exciting converter mitigates When, Vcomp reduces, and the collector voltage Vc of audion TR3 is raised, and the decreasing value of the voltage VR31 at resistance R31 two ends is only needed more Few time that can just make comparator U1 output high level, comparator U1 output high level is reduced, i.e. the second drive signal VgsL2's High level lasting time reduces, and the ON time of clamp switch pipe QL reduces；When so just achieving light load, asymmetrical half-bridge In anti exciting converter, the ON time of clamp switch pipe QL reduces, and the increase with asymmetrical half-bridge anti exciting converter output loading And increase, and reduce with the mitigation of asymmetrical half-bridge anti exciting converter output loading.

7th embodiment

Circuit theory diagrams of the Fig. 7-2 for seventh embodiment of the invention, from unlike sixth embodiment, comparator U1's is defeated Go out driving IC2 between end and the grid of clamp switch pipe QL, in order to more rapidly to drive clamp switch pipe QL, drive The output end voltage of IC2 follows the change of the input terminal voltage (i.e. the output end voltage of comparator U1) for driving IC2, increases and drives IC2 can effectively improve the driving force of whole detection control circuit.Fig. 7-3 is the voltage wave of key node in the embodiment Shape.

The above is only the preferred embodiment of the present invention, it is noted that it is right that above-mentioned preferred implementation is not construed as The restriction of the present invention, for those skilled in the art, without departing from the spirit and scope of the present invention, also Some improvements and modifications can be made, for example, the N-MOS pipe Q1 in above-described embodiment audion or P-MOS pipes is changed to；Will NPN triode in above-described embodiment is changed to N-MOS pipes or PNP triode；By two inputs of comparator U1 and phase The connection circuit that answers is exchanged, and the N-MOS pipes being connected with the outfan of comparator U1 are replaced by PNP triode or P- then Metal-oxide-semiconductor；Sample mode of change load signal etc., these improvements and modifications also should be regarded as protection scope of the present invention, here No longer repeated with embodiment, protection scope of the present invention should be defined by claim limited range.

Claims (10)

1. a kind of drive control method of asymmetrical half-bridge anti exciting converter, it is characterised in that：

Judge the load signal of asymmetrical half-bridge anti exciting converter whether less than the load point for setting；

If it is, reducing ON time of the clamped switching tube in each switch periods by drive control module, and control The ON time of clamp switch pipe reduces with the mitigation of the output loading of asymmetrical half-bridge anti exciting converter, and with asymmetric half The increase of the output loading of bridge anti exciting converter and increase so that the ON time of main switch is also with asymmetrical half-bridge flyback The mitigation of the output loading of changer and reduce, and increase with the increase of the output loading of asymmetrical half-bridge anti exciting converter； Main switch and clamp switch pipe is made to be operated in incomplementarity mode of operation, described incomplementarity refers to main switch and clamped switch The dutycycle sum of the drive voltage signal of pipe is not equal to 1；

If it is not, then by drive control module, make main switch and clamp switch pipe work in complementary working mode, described Complementation refer to main switch and clamped switching tube drive voltage signal dutycycle sum be equal to 1.

2. the drive control method of a kind of asymmetrical half-bridge anti exciting converter according to claim 1, it is characterised in that：When When the load signal of asymmetrical half-bridge anti exciting converter is detected less than the load point for setting, reduce asymmetrical half-bridge inverse-excitation converting The operating frequency of device.

3. the drive control method of a kind of asymmetrical half-bridge anti exciting converter according to claim 2, it is characterised in that：Can To reduce the operating frequency of Master control chip by peripheral circuit, and then reduce the work frequency of asymmetrical half-bridge anti exciting converter Rate.

4. a kind of asymmetrical half-bridge anti exciting converter, has used above-mentioned drive control method, including circuit of reversed excitation, described flyback Circuit includes main switch and clamp switch pipe, it is characterised in that：Described asymmetrical half-bridge anti exciting converter also includes detecting Control circuit, described detection control circuit include Master control chip, drive circuit, drive control module and load detecting electricity Road；Load detecting circuit detects the output loading of asymmetrical half-bridge anti exciting converter, compares asymmetrical half-bridge anti exciting converter Whether output loading signal is less than the load point for setting, and gives drive control mould by comparative result formation feedback signal while exporting Block and Master control chip；Master control chip output pwm signal exports two paths of signals, i.e. master switch to drive circuit, drive circuit Pipe drive signal and drive voltage signal, main switch drive signal drive turning on and off for main switch, driving voltage to believe Number it is input to drive control module；After drive control module receives drive voltage signal and feedback signal, output first drives Signal or the second drive signal are controlling the turn-on and turn-off of clamp switch pipe.

5. a kind of asymmetrical half-bridge anti exciting converter according to claim 4, it is characterised in that：Described Master control chip Output pin and GND feet including the application condition amplifier inside VCC feet, pwm signal output pin, Master control chip；VCC Foot is used for connecting power supply, and GND feet connect input ground, and pwm signal output pin is used for output pwm signal, in Master control chip The feedback signal of the outfan of the output pin connection load detecting circuit of the application condition amplifier in portion；

Described drive circuit includes that input, the first outfan and the second outfan, the effect of drive circuit are：Input termination After receiving pwm signal, through conversion, main switch drive signal and drive are exported by the first outfan and the second outfan respectively Dynamic voltage signal, described main switch drive signal are identical with described pwm signal, described drive voltage signal with Pwm signal is complementary；

Described drive control module include first comparator, the second comparator, first resistor, second resistance, 3rd resistor, One diode, the second diode, the 3rd diode, the 4th diode, the first electric capacity, the first metal-oxide-semiconductor；The first of first resistor is drawn Foot connects the second outfan of drive circuit, and the second pin of first resistor connects the first pin of the first electric capacity, the first electric capacity Second pin connection input ground；First pin of the first electric capacity is also connected with the anode of the first diode, second resistance simultaneously First pin and the input in the same direction of first comparator；The negative electrode of the first diode connects the second outfan of drive circuit；The The second pin of two resistance connects the negative electrode of the second diode, and the anode of the second diode connects the outfan of first comparator； Meanwhile, the outfan of first comparator is also connected with the grid of the first metal-oxide-semiconductor, and the source electrode of the first metal-oxide-semiconductor connects with being input into, and first First pin of the leakage connection 3rd resistor of metal-oxide-semiconductor, while be also connected with the anode of the 4th diode；The second pin of 3rd resistor Connect the negative electrode of the 4th diode, while being additionally coupled to the second outfan of drive circuit；The reverse input end of the second comparator The output pin of the application condition amplifier inside connection Master control chip, the in-phase input end connection benchmark electricity of the second comparator Pressure；The reverse input end of first comparator is also connected to the reverse input end of the second comparator, and the outfan of first comparator connects The anode of the 3rd diode is connect, the negative electrode of the 3rd diode is connected to the outfan of the second comparator；The drain electrode of the first metal-oxide-semiconductor is made For the outfan of drive control module, the control voltage signal according to the outfan of first comparator export the first drive signal and Second drive signal, drives turning on and off for clamp switch pipe.

6. a kind of asymmetrical half-bridge anti exciting converter according to claim 4, it is characterised in that：Described drive control mould Block include the first current-limiting resistance, the second current-limiting resistance, the first audion, the first Zener diode, the first charging diode, first Diode, the second diode, first comparator, second resistance, 3rd resistor and the 4th diode；The first described current-limiting resistance The first pin, the first pin of the second current-limiting resistance, the negative electrode of the first diode be connected simultaneously to the second defeated of drive circuit Go out end, the second pin of the first current-limiting resistance connects the base stage of the first audion and the negative electrode of the first Zener diode, and first is steady The anode of pressure diode connects input ground；The second pin of the second current-limiting resistance connects the colelctor electrode of the first audion；One or three pole The emitter stage of pipe connects the anode of the first charging diode, and the negative electrode of the first charging diode connects the first of the first electric capacity and draws Foot, the second pin connection input ground of the first electric capacity；First pin of the first electric capacity be also connected with the anode of the first diode, first The input in the same direction of comparator and the first pin of second resistance, the second pin of second resistance connect the moon of the second diode Pole, the anode of the second diode connect the outfan of first comparator；The outfan of first comparator is additionally coupled to the first metal-oxide-semiconductor Grid, the first metal-oxide-semiconductor source electrode connection input ground, the first metal-oxide-semiconductor drain electrode connection 3rd resistor the first pin and the 4th The anode of diode；The negative electrode of the second pin of 3rd resistor and the 4th diode is connected to the second outfan of drive circuit； The output pin of the application condition amplifier inside the reverse input end connection Master control chip of first comparator；First metal-oxide-semiconductor Drain electrode as drive control module outfan, according to first comparator output the first drive signal of signal output or second Drive signal, drives the conducting and shut-off of clamp switch pipe.

7. a kind of asymmetrical half-bridge anti exciting converter according to claim 4, it is characterised in that：Described drive control mould Block includes first comparator, the second comparator, the 5th diode, and the second electric capacity and the 4th resistance constitute peaker, the 5th electricity Resistance, second resistance and the second diode constitute positive-feedback circuit, the 4th current-limiting resistance, the 5th current-limiting resistance and the 3rd audion structure Into level shifting circuit；The output of the application condition amplifier inside the first pin connection Master control chip of the 4th current-limiting resistance Pin and the reverse input end of the second comparator, the second pin of the 4th current-limiting resistance connect the base stage of the 3rd audion；Second The input connection reference voltage in the same direction of comparator, the outfan of the second comparator connect the negative electrode of the 5th diode；Three or three The emitter stage of pole pipe connects input ground, the colelctor electrode of the 3rd audion be simultaneously connected with the second pin of the 5th current-limiting resistance, the five or two The anode of pole pipe and the reverse input end of first comparator；The first pin connection power supply VCC of the 5th current-limiting resistance；Second First pin of electric capacity connects the second outfan of drive circuit, and the second pin of the second electric capacity connects the first of the 4th resistance and draws Foot and the first pin of the 5th resistance；The second pin of the 4th resistance connects input ground；The second pin connection second of the 5th resistance First pin of resistance and the input in the same direction of first comparator；The second pin of second resistance connects the moon of the second diode Pole, the anode of the second diode connect the outfan of first comparator, and the outfan of first comparator is used as drive control module Outfan, export the first drive signal or the second drive signal and drive turning on and off for clamp switch pipe.

8. a kind of asymmetrical half-bridge anti exciting converter according to claim 5, it is characterised in that：The second described comparator Replaced with transistor control circuit, described transistor control circuit include the first divider resistance, the second divider resistance, the Two audions and the 3rd current-limiting resistance；Application condition inside the first pin connection Master control chip of the first divider resistance amplifies The output pin of device, the second pin of the first divider resistance are simultaneously connected with second pin and second audion of the second divider resistance Base stage, the emitter stage of first pin and the second audion of the second divider resistance connects input ground, the collection of the second audion jointly Electrode connects the second pin of the 3rd current-limiting resistance and the negative electrode of the 3rd diode, and the first pin of the 3rd current-limiting resistance connects power supply Power supply VCC.

9. a kind of asymmetrical half-bridge anti exciting converter according to claim 6, it is characterised in that：Described drive control module Outfan and clamp switch pipe between increase a driving IC, the drive control described in the input connection of described drivings IC The outfan of module, the outfan of described driving IC connect the grid of clamp switch pipe, to drive the conducting of clamp switch pipe With shut-off, the output voltage of described driving IC according to the change of the output voltage of the outfan of described drive control module and Change, can more quickly drive clamp switch pipe, strengthen the driving force of whole detection control circuit.

10. a kind of asymmetrical half-bridge anti exciting converter according to claim 8, it is characterised in that：Described drive control mould Increase a driving IC between the outfan of block and clamp switch pipe, the input of described driving IC connects described driving control The outfan of molding block, the outfan of described driving IC connect the grid of clamp switch pipe, to drive leading for clamp switch pipe Logical with shut-off, the change of the output voltage of described driving IC according to the output voltage of the outfan of described drive control module And change, clamp switch pipe can be more quickly driven, strengthens the driving force of whole detection control circuit.