CN209545448U - A kind of self-excited push-pull type transducer circuit, power module and power-supply system - Google Patents

Abstract

The utility model discloses a kind of self-excited push-pull type transducer circuit, power module and power-supply systems, the start-up capacitance of self-excited push-pull type transducer circuit is changed to 2 and connects as end voltage increases the capacitor that capacitance reduces, when a wherein capacitance short-circuit, an other capacitor can be because operating voltage raising causes capacitance to decline, so that the capacitance provided when the other practical capacitance provided of a capacitor and normal 2 series capacitances is not much different.The utility model can make square by start-up capacitance bring crash rate for original crash rate, in conjunction with input filter capacitor and output filter capacitor is external, the high technical problem of condenser failure bring product failure rate can easily be solved, it is further that output rectification circuit is external, it is also able to achieve product type reduction, the versatility that client uses increases.

Description

A kind of self-excited push-pull type transducer circuit, power module and power-supply system

Technical field

The utility model relates to Switching Power Supply, in particular to self-excited push-pull type transducer circuit and relevant power module and Power-supply system.

Background technique

Existing self-excited push-pull type transducer is generally speaking divided into two classes: Luo Ye circuit and the gloomy circuit of well.

Luo Ye circuit comes from the self-oscillation push-pull transistor single phase transformer of nineteen fifty-five U.S. Luo Ye (G.H.Royer) invention DC converter, often referred to simply as Royer circuit, this is also the beginning for realizing high frequency conversion control circuit；Nineteen fifty-seven, the U.S. looked into Match (Jen Sen, most document translations " well is gloomy ") has invented auto-excitation type and has recommended dual transformer circuit, referred to as self-oscillation afterwards Jensen circuit, self-excitation push-pull type Jensen circuit, most document are referred to as the gloomy circuit of well；Both circuits, descendant are referred to as Self-excited push-pull type transducer, " principle and design of Switching Power Supply " 67th of the self-excited push-pull type transducer in Electronic Industry Press Page is described to page 70, and the book ISBN is 7-121-00211-6.The principal mode of circuit is Luo Ye circuit and the gloomy circuit of well.

Fig. 1-1 shows the typical case schematic diagram of Luo Ye circuit, and application No. is 201210174076.7 (letters for corresponding China Referred to as background 1) Fig. 9, in order to enable the appended drawing reference of the application is unified, Fig. 1-1 becomes the appended drawing reference of main power transformer More in order to which B2, the name of patent application are " a kind of short-circuit protection method of self-excited push-pull type transducer ", it is gloomy that Fig. 1-2 shows well The typical case schematic diagram of circuit.

The self-oscillation of Luo Ye circuit and driving function are all completed by a transformer, and the gloomy circuit of well changes by driving transformer B1 It realizes, therefore, the main power transformer B2 of the gloomy circuit of well works in undersaturated condition.Although the driving transformer of the gloomy circuit of well There is magnetic saturation, because its is small in size, the energy of magnetic saturation consumption is small, and the global transformation efficiency ratio Luo Ye circuit of circuit is high.But Application No. is 201110436359.X and 201110436259.7 to change by November, 2011 China for such case, in Luo Ye electricity The Rong Ling magnetic core that thin portion or part have been used in road, so that conversion efficiency is substantially improved, so that the more wells of device are gloomy The living space of circuit reduces, compared with the Luo Ye circuit under the same terms, when operating voltage, load, temperature change, The self-oscillating frequency of the gloomy circuit of well is relatively stable, so, many occasions are still using the gloomy circuit of well.

For Fig. 1-2 from the start-up circuit of Fig. 1-1 the difference is that capacitor C1 connection is different, the capacitor C1 in Fig. 1-1 is direct Pin in parallel with biasing resistor R1, that wherein capacitor C1 is connect with power supply Vin, if being changed to be grounded, start-up circuit becomes soft start, As shown in Figs. 1-2, capacitor C1 is connected between feedback winding centre cap and input ground, and such connection method can solve Impact of Fig. 1-1 capacitor C1 in booting because of short circuit to triode is recommended, realizes soft start, improvement applicant is once in 2003 Year has applied for utility model patent ZL 03273278.3, in fact in " the power conversion technology " the 41st of People's Telecon Publishing House Fig. 2-18 of page is disclosed, and the Fig. 2-27 of page 56 is also disclosed, and the book ISBN is 7-115-04229-2/TN353.And Present inventor gives in the 0029th section to 0035 section of 1 authority of background and Fig. 3-1 to Fig. 3-7 of its attached drawing Existing well is gloomy or the differentiation of the biasing circuit of Luo Ye circuit, give detailed working principle, it was demonstrated that in start-up circuit Capacitor C1 takes the connection of Fig. 1-1 or Fig. 1-2 on the steady operation after the successfully starting up of circuit without influence.

Since self-excited push-pull type transducer is open loop work, frequency response is good, in small-signal model, small signal Input impedance under state is positive.And the small signal input impedance of the Switching Power Supply of various other Closed loop operations be it is negative, that is, work as When input voltage is increased because of certain reason, the consumption electric current of other Switching Power Supplies is to reduce, to maintain output power constant.Just Because the small signal input impedance of self-excited push-pull type transducer be it is positive, element is few, and reliability is high, and in parallel or cascade uses It is all very simple, therefore self-excited push-pull type transducer is difficult to be replaced by other circuit topologies, and made within following some time Power module is made as device direct marketing, be fabricated to power module method it is common there are two types of, one kind is plastic packaging, finished product Power module similar integrated circuit, using epoxy resin mixture, including filler particles, curing agent, in a mold under high temperature Molding, plastic packaging power module are easy to use；Another kind is encapsulating, and circuit board is put into shell, the two-component of polyurethane is poured into Mixture or silica gel and form, the general device for being inconvenient to be fabricated to patch type, using slightly inconvenient in engineering.

Currently, global annual output is 100,000,000 or more, and wherein well is gloomy using the power module that self-excited push-pull type transducer produces For circuit accounting still 15% or more, output power is mostly 1W, is commonly called as micropower power supply module, and manufacturer includes Japanese village field Tens companies of company, Texas Instruments, RECOM company, Germany, Taiwan MINMAX company etc. and the country, exist Following technical bottleneck.

The power module is applied to vibration occasion and often loses in use when as in automobile, motor-car, high-speed rail Effect, the especially power module of plastic packaging class, due to power module sealing moulding, can only integral replacing, the probability of failure is not Height, the crash rate to come into operation 1 year of installing is about one thousandth, i.e. 1000ppm, this is unacceptable, vapour in automobile industry Garage's industry is contemplated to be zero-fault, and according to the tub curve in failure mechanism, failure is relatively high, automobile industry in First Year Minimum expectation can be in 8ppm hereinafter, i.e. 8/1000000ths in the crash rate of First Year, while the global failure rate in 10 years Meet 8ppm or less.

The product failure rate produced of technique the most advanced can only achieve 300ppm or so both at home and abroad at present, and client It is acceptable only 8ppm, once have defective products by shipment, these defective products will be widely used in automobile, rail traffic, It is very serious such as to cause damage sequence for the fields such as mechanical equipment and industrial communication, therefore manufacturer can only be in online preceding progress Detection, it is ensured that be ability upper plate installation after 100% qualification, but still have defective products appearance, in this regard, auto producer and micropower power supply Module factory all tries every means, and is such as changed to the former brand of global ranking, but problem still occurs in user's use. The cost paid after sale is high, and caused claim is also very high.

Since micropower power supply module is used in the temperature such as automobile, humidity environment rugged environment, product requirement uses modeling Envelope or encapsulating, improve its environmental suitability, after this also results in product failure, will destroy power module in dismantling, thus Extremely difficult carry out failure analysis, also can not the ultimate improvement of further progress, realize zero-fault.

In addition, power module application is multifarious, to its input voltage, output voltage, output number, isolation pressure resistance And the requirement of encapsulation etc. can also have very more demands, for power module manufacturer, be all at present will export it is whole Current circuit is integrated in inside power module, it means that and the product of single channel output and two-way output needs respectively to manufacture and design, this Meeting leads to the increase of management cost and warehousing pressure so that the model of power module manufacturer is double.

Utility model content

In view of this, the technical problem to be solved by the present invention is to provide a kind of self-excited push-pull type transducer circuit, with And the power module using the self-excited push-pull type transducer circuit, the crash rate of power module can be reduced, social cost damage is reduced It loses, and the management cost and warehousing pressure of manufacturer can be reduced, the utility model is also provided using the power module simultaneously Power-supply system facilitates client to use, and is able to achieve using upper expansion.

Present invention design can have a detailed description later, and main thought is to find out failure mechanism, recycle TRIZ The scheme for solving failure is provided, the technical solution that the utility model solves above-mentioned technical problem is as follows:

A kind of self-excited push-pull type transducer circuit, includes at least: input anode, input ground, start-up circuit, driving part, Triode TR1 and triode TR2, main transformer B2 and two output ends；Start-up circuit includes at least two terminals, that is, opens Dynamic input terminal and starting output end；Driving part includes at least three terminals, i.e. driving input terminal and two drive outputs；It is main Transformer B2 includes at least two primary side winding N_P1And N_P2An and vice-side winding N_S1；Starting input terminal connection self-excitation is recommended The input anode of formula converter circuit, starting output end connection driving input terminal；The emitter of triode TR1 and triode TR2 With being connected to the input of self-excited push-pull type transducer circuit, collector is separately connected primary side winding N_P1And N_P2Two ends, Base stage is separately connected two drive outputs；Primary side winding N_P1And N_P2Centre cap connect self-excited push-pull type transducer circuit Input anode；Vice-side winding N_S1Both ends connection self-excited push-pull type transducer circuit two output ends；Start-up circuit is at least Device and start-up capacitance are provided including electric current, it is one of following two that electric current, which provides device and the connection relationship of start-up capacitance:

(1) electric current provides device and start-up capacitance is in parallel, and one end is starting input terminal after parallel connection, the other end is starting output End；

(2) electric current provides device and start-up capacitance series connection, and it is to start input terminal, the other end to open that electric current, which provides device one end, Dynamic output end, start-up capacitance are connected on electric current and provide between the device other end and the input ground of self-excited push-pull type transducer circuit；

It is characterized by: start-up capacitance includes 2 concatenated capacitors, and 2 concatenated capacitance characteristics are with end voltage It increases, capacitance reduces.

Preferably, 2 concatenated capacitors are chip multilayer ceramic capacitor.

Preferably, it is resistance that electric current, which provides device, or is constant-current source device.

For the self-excited push-pull type transducer circuit of Luo Ye circuit, driving part is two be designed in main transformer B2 Feedback winding N_B1And N_B2, feedback winding N_B1And N_B2Centre cap be driving input terminal, feedback winding N_B1And N_B2Two end Head is two drive outputs.

The first improvement of self-excited push-pull type transducer circuit as above-mentioned Luo Ye circuit, main transformer B2 magnetic core by Principal part and part composition, principal part is identical with local material, and sectional area is different；Or principal part is identical with local sectional area, material is not Together.

Second of improvement of the self-excited push-pull type transducer circuit as above-mentioned Luo Ye circuit, recommends triode at its two A capacitor is connected between TR1 and the collector of TR2.

Preferably, the capacitor's capacity connected between above-mentioned two triode TR1 and the collector of triode TR2 is less than 1000pf。

The self-excited push-pull type transducer circuit of circuit gloomy for well, driving part are the driving transformer B1 of independent design, It further include resistance R2 in driving part, driving transformer B1 includes primary side winding N_mAnd two feedback winding N_B1And N_B2, feedback Winding N_B1And N_B2Centre cap be driving input terminal, feedback winding N_B1And N_B2Two ends be two drive outputs, Primary side winding N_mIt connects with resistance R2, two terminals after series connection are respectively connected to the collector of triode TR1, TR2.

The first improvement of self-excited push-pull type transducer circuit as the gloomy circuit of above-mentioned well, driving transformer B1 magnetic core It is made of principal part and part, principal part is identical with local material, and sectional area is different；Or principal part is identical with local sectional area, material It is different.

Second of improvement of the self-excited push-pull type transducer circuit as the gloomy circuit of above-mentioned well, the both ends resistance R2 are one in parallel Capacitor.

Accordingly, power module technical solution provided by the utility model is as follows:

A kind of power module includes at least four terminals, respectively input plus end, input ground, two output terminals, Be characterized in that: including above-mentioned self-excited push-pull type transducer circuit, the input anode of self-excited push-pull type transducer circuit, input ground and Two output ends be correspondingly connected to power module input plus end, input and two output terminals.

The technical solution of above-mentioned self-excited push-pull type transducer circuit and power module is open expression way, i.e., may be used also To include certain other functional circuits, such as input filter circuit, output filter circuit and output rectification circuit, this is practical new Type power module following two technical solution requires to further include or clearly exclude the certain others for including inside power module Functional circuit.Note: some functional circuit can be only a component, if capacitor can be input filter circuit, output filtering Circuit, diode can be output rectification circuit.The technical solution of this two power modules is as follows:

It particularly, further include output rectification circuit in above-mentioned power module.

It particularly, does not include input filter capacitor, output filter capacitor in above-mentioned power module.

When in the power module of the utility model not including input filter capacitor and output filter capacitor, using the power supply The technical solution of the power-supply system of module is as follows:

A kind of power-supply system, it is characterised in that: including external input filter capacitor and output filter capacitor and above-mentioned Power module, input filter capacitor and the input plus end of power module and inputs in parallel, output filter capacitor and power supply mould Two output terminal parallel connections of block, and input filter capacitor and the distance between output filter capacitor and power module all≤λ/ 11, λ be the corresponding wavelength of working frequency of power module.

The utility model relates to noun explain it is as follows:

Input filter capacitor: it is connected to the capacitor of self-excited push-pull type transducer circuit input end, for filtering out input voltage In ripple, such as the capacitor C2 in Fig. 1-1 and Fig. 1-2.It can be the filtered electrical perhaps battery of higher level's power supply itself, contain Super capacitor.

Output filter capacitor: it is connected to the capacitor of self-excited push-pull type transducer circuit output end, for filtering out output voltage In ripple, such as the capacitor C3 in Fig. 1-1 and Fig. 1-2.It can be input filter capacitor or the battery itself of lower level power supply, Containing super capacitor.

Output rectification circuit: the circuit being connected between self-excited push-pull type transducer circuit vice-side winding and output end is used In the positive and negative ac voltage rectifier for exporting vice-side winding be direct voltage output, as in Fig. 1-1 and Fig. 1-2 diode Da and The circuit of Db composition.

Start-up capacitance: the capacitor of self-excited push-pull type transducer circuit quick start or soft start is realized, such as Fig. 1-1 and Fig. 1- Capacitor C1 in 2.Not only there is effect on startup, start-up capacitance still works in normal work, as it was noted above, in background There is discussion in 1 authority.

Recommend triode: realizing the triode of self-excitation push-pull type work, as in Fig. 1-1 and Fig. 1-2 triode TR1 and TR2。

Driving transformer: the gloomy circuit of well individually completes self-oscillation and driving function by magnetic saturation transformer, and the application should Magnetic saturation transformer is referred to as driving transformer, such as the B1 in Fig. 1-2.

Main transformer: voltage transformation is institute for the transformer to load transmission energy by the abbreviation of main power transformer The numerical value needed, primary side centre cap are connected to power supply, i.e., the self-excitation operating voltage of pushing off formula converter, primary side are another Two terminals are connected with two collectors for recommending triode respectively, and vice-side winding connects one or more output rectification circuit, such as Transformer B2 in Fig. 1-1 and Fig. 1-2.

Feedback winding centre cap: referring to and be connected to two centre caps for recommending the winding between transistor base, such as schemes The winding N of the main transformer B2 of 1-1_B1And N_B2Centre cap or Fig. 1-2 in driving transformer B1 winding N_B1And N_B2In Heart tap.

The power module of the utility model solves related personnel for a long time and thirsts for always solving but fail to obtain always Successful technical problem, discovery procedure and method and working principle will be analyzed in a particular embodiment, not go to live in the household of one's in-laws on getting married herein It states.

Having the beneficial effect that for formula converter is pushed off in the self-excitation of the utility model

(1) crash rate is greatly reduced, and 1ppm crash rate below may be implemented, meet the needs of automotive grade；

(2) product type will be reduced, and the versatility that client uses increases.

Detailed description of the invention

Fig. 1-1 is the typical case schematic diagram of Luo Ye circuit；

Fig. 1-2 is the typical case schematic diagram of the gloomy circuit of well；

Fig. 2 show capacitance change curve of the ceramic condenser used by the utility model start-up circuit under Dc bias Figure；

Fig. 3 is the utility model first embodiment power module exemplar schematic figure；

Fig. 3-1 is the waveform diagram of the utility model first embodiment output voltage；

Fig. 3-2 is the schematic diagram of the external output rectification of the utility model first embodiment client and filter circuit；

In the absence of Fig. 3-3 is Fig. 3-2 hypothesis filter capacitor C3 and using voltage oscillogram when purely resistive load；

Fig. 3-4 is the schematic diagram for the doubleway output that the utility model first embodiment obtains altogether；

Fig. 3-5 is the schematic diagram that the utility model first embodiment obtains multiplication of voltage output；

Fig. 3-6 is that vice-side winding obtains the schematic diagram of independent doubleway output to the increase of the utility model first embodiment all the way, And the schematic diagram applied in the power supply system for the 5th embodiment power module of the utility model.

Fig. 3-7 is that the implementation start-up circuit of the utility model first replaces with the schematic diagram after capacitor C1 and resistance R1 parallel connection；

Fig. 4 is the utility model second embodiment power module exemplar schematic figure；

Fig. 4-1 is the schematic diagram for the doubleway output that the utility model second embodiment obtains altogether；

Fig. 4-2 is that vice-side winding obtains the schematic diagram of independent doubleway output to the increase of the utility model second embodiment all the way；

Fig. 5-1 is one of the utility model 3rd embodiment power module main transformer core structure schematic diagram；

Fig. 5-2 is the two of the utility model 3rd embodiment power module main transformer core structure schematic diagram；

Fig. 5-3 is the three of the utility model 3rd embodiment power module main transformer core structure schematic diagram；

Fig. 6 is the utility model fourth embodiment power module exemplar schematic figure.

Specific embodiment

The targeted failure of the utility model is that industry wishes the technical problem captured for a long time, and power module product makes Its environmental suitability is improved with plastic packaging or encapsulating, after this also results in product failure, will destroy power module in dismantling, Thus extremely difficult carry out failure analysis, also can not the ultimate improvement of further progress.

Applicant has collected the sample much to fail, analyzes by traditional method, obtained conclusion is all to recommend use nothing but Triode breakdown, power module due to again acting as device on circuit boards, again undergo Reflow Soldering and cause capacitor and open It splits, causes short circuit, or the internal rectification used is punctured with Schottky diode.

Inventor notices, and reflected short circuit outside electric power source pair of module, short-circuit impedance is distributed more widely, from 0.1 Ω to Nearly 10 Ω has, more in 2 Ω or so, this is different from the reflected distribution of semiconductor failure, and conjecture is that other reasons cause Failure, but consult many data, seeked advice from domestic many experts, all without compellent explanation, at this moment, work together Liu Kun Bright proposition, if the caused short circuit in second of Reflow Soldering for pure tin.Power module itself in production, the tin cream used Be alloy, be called solder(ing) paste, be mainly made of scaling powder and solder powder, solder powder is also known as glass putty, mainly by tin-lead, tin bismuth, Tin Silver Copper Alloy composition, as other producers, has selected high-melting-point solder(ing) paste, for fusing point at 280 DEG C or more, its feature is to contain Lead amount is high, this be also for high reliability request industry lead content is not required and the high lead welding tin that uses, normally, Client when device Reflow Soldering again, temperature be strict controlled in 260 DEG C it is below, the solder joint inside power module should not It melts again, puts into tens of thousands of products, every batch of 5000, tested with different temperatures, discovery temperature between 235 degree to 265 degree In range, product will appear failure really, predominantly short-circuit.The fusing point of pure tin is 231.89 DEG C, but inside power module Pure tin from where come.

The pin of power module internal components is mostly the pin of pure tin coating covering, and applicant has reused this technology neck The common method in domain: method of substitution.With electrochemical process, tin is removed to the device pin strip of participation, and plates silver layer, fusing point exists 961 DEG C or more, it should overcome the problems, such as this, but result still has short circuit, by the pebble glue slice analysis that expense is high, It was found that being still short circuit caused by pure tin, further associating is that tin grain diameter is excessive in solder(ing) paste, it is desirable that solder(ing) paste supplier exists When prepared by glass putty, electric spark current is reduced, and obtains the tin grain of smaller diameter, and solder(ing) paste supplier has directlyed adopt Japan, Germany The raw material of smallest particles on the earth of import cooperate industry to solve the problems, such as, experiments have shown that, there are still almost the same crash rates.

At this moment, it is patch type capacitor that inventor, which notices the capacitor in power module, and industry is sheet type multi-layer ceramic Capacitor, english abbreviation MLCC, is commonly called as patch capacitor, what it was misplaced by the ceramic dielectric diaphragm of printed electrode (interior electrode) Mode is superimposed together, and forms ceramic chip by disposable high temperature sintering, then seal up metal layer (external electrode) at the both ends of chip, To realize required capacitance and other parameter characteristics.There is multilayer inside this capacitor, interior electrode is silver layer, and there are also dielectric Ceramic material, their thermal expansion coefficient is different, as muti-piece biscuit is superimposed, in patch it is difficult to ensure that therein Shape face is parallel with circuit board, if the case where also will appear vertical 90 degree, i.e., capacitor is in patch, if is axially revolved Turned 90 degree, note: axis passes through the geometric center of two terminals.By polyester resin slice analysis, there are 10 samples of short circuit in discovery Product, 8 only because capacitor is rotated by 90 degree of patches, and inventor's guess: capacitor is rotated by after 90 degree, with circuit board water On the basis of placing flat, there are many potential grooves in the top parallel with circuit board, and at high temperature, pure tin is first melting, is moulded Envelope or the closed environment of encapsulating influence, and dart forward in this groove, two ends of short circuit.Chip mounter itself is impossible This move is completed, inquires that the supplier of patch capacitor, the supplier of capacitor recognize that capacitor is material of the random braid in plate-like In disk, i.e., in patch, it is possible to which nearly 50% probability has been axial-rotation 90 degree.

This only guesses that, when including polyester resin slice dismantling product, short circuit can disappear, and can not verify this guess, send out Bright people proposes new experimental method again: from the external power supply for using low-voltage, high-current, can the internal resistance that formed using short circuit be sent out Heat dissolves tin, and using the surface tension of liquid tin, spherical shape is voluntarily retracted into, or have this trend, so that short dot be allowed to disappear Lose? by calculating, with Binding experiment, maximum output voltage 5V, the power supply of constant current output 2A, to the electricity of input terminal shortcircuit are finally used Source module is tested, and discovery short dot really disappears；The power module of power module outlet short circuit is tested, Polarity is needed to pay attention to, internal rectifier diode otherwise can be burnt, discovery short dot equally disappears, the performance recovery of product.

In client when device Reflow Soldering again, in flowing, part pure tin can be in pure tin because of the effect of surface tension Spherical tin ball is distributed in groove as water droplet, does not cause short circuit, but in terminal client in use, due to vibration It influences, tin club is mobile, to cause short circuit.Such case makes with the aforedescribed process, can not repair in advance.

In addition, in 10 above-mentioned samples, caused by being not as the short circuit that pure tin causes there are also 2, using above-mentioned Method can not repair in advance.By careful slice analysis, this two short-circuit reasons are as follows: capacitor cracking causes, multi-layer ceramics After capacitor cracking, the corresponding silver layer of two terminals can be staggered, and can also cause short circuit, and this short circuit can not repair with the aforedescribed process It is multiple.From 2011 to 2018 year, a large amount of visitor moves back product sampling analysis and sees, capacitor cracking accounting about always fail 22% or so. Plastic packaging product especially using the lead frame of sheet metal as circuit board, ratio are higher.

Root is had found because after, solves the problems, such as this scheme, it appears that have, that is, should not input capacitance and output filtering Capacitor, start-up capacitance in normal work, influence efficiency and output short circuit protection, can not save.But client must be will not Agree to, client can think in this way: should not input filter capacitor and output filter capacitor, this obviously reduces the property of power module Can, Electro Magnetic Compatibility is centainly also deteriorating.

Since the inside is 3 multilayer ceramic capacitors, average one crash rate is 333ppm, should not input capacitance and defeated Filter capacitor out, crash rate is still in 333ppm, and using the bigger capacitor of volume, such as 0805 capacitor is changed to the electricity of 1210 encapsulation Hold, it is expected to solve the problems, such as this, but the factory of multilayer ceramic capacitor, headed by TDK, every factory is all being minimized, even 0805 encapsulation will withdraw from the market, and mainstream is with 0603, or even to 0402 evolution, as mobile phone industry is using The multilayer ceramic capacitor of 0201 encapsulation.

If the scheme that the utility model is taken is the start-up capacitance that this can not be removed, using two patch capacitors Series connection, when wherein a short circuit, another still work, but one times of volume change, the characteristic variations of power module are larger, client It is not easily accepted by.

Even if having found root because start-up capacitance can be split as two concatenated capacitors, seem and be readily apparent that, but ability The concatenated general purpose of capacitor is provided to improve pressure resistance by the technical staff in domain, also has the case where for reducing capacitance, at this time It is that smaller capacitance can be obtained by concatenated mode, such application is by used because the capacitor of standard capacitance is improper at hand Property thinking influence it is actually rare.And other capacitors are external is readily apparent that for a person skilled in the art, but it is restricted In the limitation that electromagnetic compatibility standard requires, someone is not it is thought that feasible solution, even if therefore both at home and abroad the most first Into manufacturer, be all directed to the improvement of welding material and welding procedure all the time, 2011 to 2013 Japanese villages Tian company has just applied for that the multinomial patent of welding material and welding procedure carrys out the power supply mould for self-excited push-pull type transducer circuit Block.Although can not be further decreased always so that being widely used since the nineteen fifty-five circuit generates after more than 60 years Crash rate.

Present inventor breaks through conventional thought, proposes that start-up capacitance C1 is readily modified as two capacitor C11 and C12 strings Connection and input filter capacitor C2, output filter capacitor C3 can be external, and theoretical basis is as follows:

(1) start-up capacitance C1 is readily modified as two concatenated theoretical basis of capacitor C11 and C12

The utility model start-up capacitance C1 is readily modified as two capacitor C11 and C12 series connection, and Yao Shixian purpose of utility model is also It is required that the capacitance of two capacitors C11 and C12 decline with the increase of end voltage, according to capacitance characteristic it is found that in series capacitance Each capacitor's capacity and total capacitance relationship it is as follows:

C₁₁×C₁₂/(C₁₁+C₁₂)=C₁

Here the capacitance of corresponding capacitor, C are indicated with subscript₁₁Indicate the capacitance of C11, C₁₂Indicate the capacitance of C12, C₁Indicate C1 Capacitance, therefore, C under nominal case₁₁> C₁, C₁₂> C₁.In normal circumstances, in order to reduce cost, C11 and C12 can be adopted With the capacitor of same model, then, calculating becomes very simple, and total capacity is the half that monomer participates in series capacitance, i.e. C₁= 0.5C₁₁=0.5C₁₂。

Assuming that the capacitor C12 short circuit in capacitor C11, C12, holds C11 work for residual electricity, whole capacitances are therefore only by capacitor C11 is provided, for example nominal case, before analyzed C₁₁> C₁, C₁₁=2C₁For one times of relationship.But after capacitor C12 short circuit Originally the operating voltage for giving capacitor C12 can also be applied to the both ends capacitor C11, and the operating voltage of capacitor C11 will increase one times, by In the characteristic of multilayer ceramic capacitor are as follows: capacitance declines with the increase of end voltage, therefore the capacitance of capacitor C11 has at this time Declined, it is assumed that the capacitance of decline is Δ C, then the capacitance after capacitor C11 decline is (C₁₁Δ C), it is set by reasonable parameter Meter, may be implemented (C₁₁Δ V) and C₁It is not much different, so as to realize purpose of utility model.

And by probability theory it is found that if wherein a capacitance short-circuit cause failure probability be 333ppm, two Series capacitance is simultaneously because short circuit causes the probability of failure to be 333ppm × 333ppm, multiplied result 0.11ppm, crash rate moment Unexpected decline is obtained, it is final to lose if input filter capacitor and output filter capacitor to be also all changed to two series connection Efficiency is 1ppm, easily meets client to the quality requirements of product, is limited by requirement of the client to small product size, input filter Capacitor and output filter capacitor are also changed to two and unrealistic, and ideal solution is they are external, the two electricity Hold can external theoretical basis will be described below in detail.

So, characteristic is how the capacitor that capacitance declines with the increase of end voltage obtains, those skilled in the art Member is known that the capacitor of high-quality, as the raising capacitance variation of end voltage is smaller, current domestic quality is not high Chip multilayer ceramic capacitor (hereinafter referred to as domestic patch capacitor) is limited by piezoelectricity pottery due to using piezoceramic material The electrical characteristics of porcelain itself, the characteristics of showing, are exactly substantially reduced as end voltage increases capacitance.

Fig. 2 show capacitance change curve of the ceramic condenser used by the utility model start-up circuit under Dc bias Figure, 473K/10V of the test sample from certain domestic company, 0603, X7R chip multilayer ceramic capacitor, i.e. capacity are The patch capacitor of 0.047uF, the figure are inventor's actual measurement.It can be seen that DC offset voltage by the curve graph to be positive and be Capacitance change curve when negative is symmetrical, and with the increase of DC offset voltage, the capacitance of capacitor declines, when DC offset voltage increases When being added to 10V, the capacitance of capacitor is only the 5% of nominal value.This undesirable feature is that each patch capacitor factory is deliberately returned It keeps away, on their service manual, can all ignore this curve, or the curve after beautification is showed user, but also with Patch capacitor has been forgotten at family, and there is also this undesirable features.

Current embodiment require that the exactly not high MLCC capacitor of this quality, to just be able to achieve series capacitance wherein one Short circuit, in addition one causes capacitance to decline because operating voltage increases, thus the other practical capacitance provided of a capacitor and two The capacitance that series capacitance provides when normal is not much different, not only can solve in this way capacitance short-circuit bring product failure rate occupy it is high Technical problem under not also makes the undesirable feature of low-quality capacitor be turned bane into boon, to realize the cost of raw material It reduces.It is well known that the capacitor of NPO or C0G, capacitance is extremely stable, same capacity, more than ten times at high cost, capacitance and electricity The relationship of pressure is very weak, it is clear that is not preferably used in the utility model, effect is poor.And the characteristic of X7R is poor, effect is fine.And The worse patch capacitor of the characteristics such as X5R or Y5U, effect are more preferable.

(2) theoretical basis that input filter capacitor C2, output filter capacitor C3 can be external

It is theoretical according to well known electricity, have: C=λ f

Wherein: C: electromagnetic wave propagation speed is 3 × 10⁸m/s；λ: wavelength, unit m；F: frequency, unit Hz；

Distance≤λ/11 of the external capacitor of the requires of the utility model apart from power module, at this time its to space generate electromagnetism Radiate it is very little, can be considered not to space generate electromagnetic radiation, be lost it is also smaller, effect is preferable.Relevant theoretical foundation does not have Have a direct argument, it is closer can " minimal tour be designed in EMC with reference to the 21st Annual Conference paper of Chinese power supply association In application ", paper is delivered in November, 2015, the Authors of Science Articles be present inventor, the article pointed out " high-frequency signal If 1/4 wavelength is identical as the length of antenna, antenna just has good radiation and reception ability ... antenna once being formed, that There are when step signal in circuit, the frequency which can select resonance therewith automatically is launched ", and the utility model Transformer output is exactly square wave, and rising edge or failing edge are exactly step signal, then, it is external in order to reduce external radiation Distance of the capacitor apart from power module will within 1/4 wavelength, more preferably, in less than half of 1/4 wavelength, i.e. 1/8 wavelength with Under.In order to further ensure effect, distance of the external capacitor apart from power module will 1/4 wavelength golden section point with It is interior, i.e., it is 0.382 times of 1/4 wavelength (1-0.618), it is closest for λ/11.

Since the working frequency of self-excited push-pull type transducer circuit is mainly 50kHz, 100kHz and 200kHz, highest at present Frequency can accomplish 1MHz, and future is expected to realize the breakthrough of 10MHz, for the self-excited push-pull type transducer electricity of different operating frequency Road, distance of the external capacitor apart from power module calculate as follows:

Working frequency	Wavelength X	λ/11
			50kHz	6000m	545.4m
100kHz	3000m	272.7m
			200kHz	1500m	136.3m
1MHz	300m	27.27m
			10MHz	30m	2.727m

There are when step signal in circuit, the frequency which can select resonance therewith automatically is launched, according to engineering 19 subharmonic of experience, harmonic wave still have very considerable radianting capacity, even if by the working frequency of self-excited push-pull type transducer circuit Multiplied by 19, then, distance of the external capacitor apart from power module will be within 1/the 19 of 1/11 wavelength, i.e. 1/209 wavelength Within, it is still able to satisfy the requirement of electromagnetic compatibility standard, the following are distance of the external capacitor apart from power module in such cases Calculated result:

When module working frequency is 1MHz, distance is 1.44 meters, still can guarantee the performance of electromagnetic compatibility.

First embodiment

Referring to Fig. 3, Fig. 3 is the utility model first embodiment power module exemplar schematic figure, use similar integrated There are pin in the technique of painting of circuit, outside, and the empty thick line of outline border indicates that internal device integrates encapsulation, the empty thick line of outline border It does not indicate to be electrically connected, power module includes input plus end Vin, input ground GND and two output terminal Out1 and Out2, electricity It include: resistance R1, capacitor C11, capacitor C12, triode TR1, triode TR2, main transformer B2, primary side winding inside source module N_P1And N_P2, feedback winding N_B1And N_B2And vice-side winding N_S1；One end connection input plus end of resistance R1, resistance R1's is another Connection input ground after capacitor C12, capacitor C11 that one end is concatenated；The emitter of triode TR1 and TR2 are connected to input ground, Collector is separately connected primary side winding N_P1And N_P2Two ends, base stage is separately connected feedback winding N_B1And N_B2Two ends； Primary side winding N_P1And N_P2Centre cap connection power module input plus end；Vice-side winding N_S1Both ends connect power supply mould Two output terminals of block.

Self-excited push-pull type transducer circuit inside the power module of the present embodiment is the Luo Ye circuit of soft starting mode, Capacitor C11 and capacitor C12 is asked to decline with the increase of end voltage, without integrated input filter capacitor, defeated inside power module Filter capacitor and output rectification circuit out.Obviously, capacitor C11 and capacitor C12 transposition equally realize purpose of utility model.

Fig. 3-1 is the waveform diagram of the present embodiment output voltage, compared with technology, the square wave being alternately present for generating positive and negative voltage； Single channel output voltage can be obtained after the circuit shown in the external Fig. 3-2 of client, due to having only used a diode D1, works as output Filter capacitor C3 is not present, and when use purely resistive load, the waveform diagram of output voltage is exported as shown in Fig. 3-3 for half-wave, At this moment the capacity of C3 should increase, discussed above to obtain the ripple voltage to meet the requirements, when module working frequency is 1MHz When, distance is 1.44 meters, still can guarantee the performance of electromagnetic compatibility.That is within C3 is from 1.44 meters of power module, it is obvious that In the system of client, the original decoupling capacitance that can use in its system completely serves as C3, and is increased without cost, due to original Decoupling capacitance may be that the ceramic condenser of electrolytic capacitor and 1000pF to 0.1uF composes in parallel, population size is because use Such as tantalum solid electrolyte capacitor and it is bigger, therefore filter effect can be fine.Half-wave output can't be made to recommending with triode At any adverse effect, only wherein a triode is constantly in light condition.

When the diode D1 in Fig. 3-2 is reversely connected, so that it may obtain negative voltage output, no longer individually be arranged with embodiment Out.Certainly, directly the upper lead tie point of the cathode of diode D1 in Fig. 3-2 and C3 as direct current output ground wire, then with The connected DC output end of another lead of C3 will export a negative pressure, equally can work normally.Diode D1 it Before, i.e. the rising edge of square wave still can be absorbed under in the two of Fig. 3 output terminals low capacity filter capacitor directly in parallel Edge is dropped, the promotion of Electro Magnetic Compatibility is conducive to.

Due to there is no diode inside power module, it is well known that since Switching Power Supply working frequency is higher, export whole Stream diode mostly uses Schottky diode,, can again after client mounts or inserts onto their circuit as power module Secondary Reflow Soldering or wave-soldering, and most device, are all to be resistant to 12 seconds by equivalent 260 DEG C to design, bear 2 high temperature, right For Schottky diode, caused failure is steeply risen.European Union is instructed by RoHS and WEEE, is prohibited on July 1st, 2006 Lead and other harmful substances matter are only used, has pulled open the beginning of electronic product high-temperature soldering, the fusing point of traditional tin-lead eutectic solder is 183 DEG C, and the fusing point of tin silver copper (SAC) lead-free solder for gaining universal acceptance and being widely used at present is about 217 DEG C, so that Thermotropic failure aggravates significantly, and each related device manufacturer was studied by many years, just allows device that can support 12 seconds at 260 DEG C Welding, to show oneself reliability.This is not represented, and for device at 260 DEG C, it is lossless, device that welding in 12 seconds, which is reliable, Part manufacturer can only guarantee that under this high temperature, crash rate is lower than some value.The same period, the electronic product as high-quality produce Quotient, the temperature of Reflow Soldering are still controlled at 245 DEG C or less；Here we will notice a fact, and this kind of product is civilian goods, longevity Order it is of less demanding, can be continuous work 3000 hours such as MP3, the satisfaction of consumer after 3000 hours, is reprocessed with regard to relatively high Rate has been just good product lower than 3%, and this is required, and will cause great complaint for Switching Power Supply.For automobile, Can not even more it receive.

From the perspective of science, continuous high temperature has negative effect to semiconductor.Concentrated expression are as follows: insulation performance is moved back Change；Component directly damages；The heat ageing of material.This obtains and talks about from the characteristic of semiconductor, and current used in electronic industry is partly led Body, is often referred to silicon semiconductor, silicon itself be it is very intrepid, fusing point is 1410 DEG C, this do not represent it is bad to 1410 DEG C of, generally At 165 DEG C, the silicon semiconductor of energization just substantially because of a large amount of appearance of few son, the displacement of few son and directly damage Silicon semiconductor；In Schottky diode, usual doping concentration is higher, and the electric conductivity of semiconductor will become better, and pressure drop is got over It is low, the reason is that can enter the electron amount of conduction band can increase as doping concentration improves.The very high semiconductor of doping concentration It can be widely used in Schottky diode because of electric conductivity close to metal.High temperature reflux weldering again etc., silicon semiconductor is most Pipe is not powered, and can survive, but at high temperature, a large amount of appearance of few son, combination, the regeneration of He Duozi, omnidirectional Movement still has damage semiconductor PN.It is well known that the silicon semiconductor of energization is just as few under 165 DEG C of junction temperature A large amount of appearance of son lack the displacement of son and directly damage silicon semiconductor.

The present embodiment is external rectifier diode, so that rectifier diode is solely subjected to once weld high temperature, it is clear that reduce The crash rate of whole system improves the reliability of whole system.

Rectifier diode is external, since external capacitor C3 is easy to be amplified with the electrolytic capacitor of low cost, so that power supply The vice-side winding of module is reduced to a winding, has been saved cost by two windings in Fig. 1-1, Fig. 1-2.

Rectifier diode is external, also obtains another the utility model has the advantages that easily obtain doubleway output altogether, referring to Fig. 3-4, It can be obtained doubleway output, recommend with triode all in there is load state.

Further, if using the negative output in Fig. 3-4 as ground wire, then, so that it may multiplication of voltage output is obtained, is such as expected 18V DC voltage, it is only necessary to using the power module of the 9V of the utility model, use the usage of Fig. 3-5.

Rectifier diode is external, also obtains another the utility model has the advantages that easily obtaining the output of independent two-way or more, independence is double Road refers to them not altogether, and Fig. 3-6 gives this power module and usage thereof: increasing vice-side winding N all the way_S2, accordingly Ground, external rectifier diode increase D2, and filter capacitor increases C5, obtain another way DC output voltage, i.e., in figure DCout2 this Road, voltage can be identical as this road Dcout1, can also be different, and change the turn ratio, and the positive-negative polarity of two-way voltage Can arbitrarily it be arranged.The Same Name of Ends of secondary side two-way is noticed in Fig. 3-6, this is in order to ensure recommending with triode all in there is load shape State.It is traditional to obtain the two-way not scheme on ground altogether using Fig. 1-1, Fig. 1-2 technical solution, it is secondary while to use 4 it is secondary while around Group, at high cost, coiling is difficult.The technical solution of Fig. 3-6 is further added by a diode, can obtain the output of three tunnels, Zhong Second Road Altogether, not altogether with third road；It is further further added by a diode, totally four diodes, can get the output of four tunnels, wherein the All the way, altogether, altogether, the first via, the second road and tetra- tunnel third Lu Yu are not altogether on tetra- tunnel third Lu Yu on the second tunnel.

It should be noted that the start-up circuit of the present embodiment is made of resistance R1 and capacitor C1, resistance R1 provides for electric current Device provides starting voltage for power module, and resistance R1 can be substituted with resistance shunt capacitance or constant-current source, equally can be real The electricity of the spike on triode TR1 and triode TR2 can be absorbed when power module powers on by existing purpose of utility model, capacitor C1 Pressure avoids triode from therefore burning, to realize the soft start of power module.Fig. 3-7 shows the another of first embodiment Kind alternate embodiments, start-up circuit include that electric current provides device resistance R1 and capacitor C1, and the one end resistance R1 is starting input terminal, The other end is starting output end, and capacitor C1 and resistance R1 are in parallel, and resistance R1 can be substituted with constant-current source device, the use of this constant-current source Method has been filled part in China is application No. is 201110200894.5 and is disclosed, and no longer provides explanation here.

In addition, the self-excited push-pull type transducer circuit inside the present embodiment power module also can be replaced other embodiment party Start-up circuit in formula, the gloomy circuit of well as shown in Figs. 1-2 or Fig. 1-2 is changed to the circuit after mode shown in Fig. 1-1, these Purpose of utility model may be implemented in alternate embodiments, is not unfolded to illustrate one by one herein.

Certainly, on the concatenated tie point of C11 and C12, a high resistance measurement, such as 10K or more, high resistance measurement are connect The other end connection input anode or input ground, implementation result can be promoted further, only in the power module of volume very little, Increase an element, is all the original design intention for having violated module: it is small size, highly reliable, in the present invention, do not advocate this The postiche usage of kind.

Second embodiment

Referring to Fig. 4, be the utility model second embodiment power module schematic diagram, it is different from Fig. 3 of first embodiment Place is for output rectifier diode D1 shown in Fig. 3-2 to be integrated into inside power module, for being reluctant that exterior design is defeated Out for the client of rectification circuit, such design can satisfy its demand.Remove inside the present embodiment input filter capacitor and Output filter capacitor, the power-supply system of client still can satisfy the design method of electromagnetic compatibility and theoretical foundation has been said above It is bright, it does not or else repeat equally herein.

The beneficial effect of second embodiment is, the original system of client can directly use the without making any change Original module of power module substitution such as Fig. 1-1, Fig. 1-2 of two embodiments, it is extremely easy to use.

Equally, the diode that second embodiment is internally integrated is further added by a diode D2, obtains the embodiment of Fig. 4-1, It can get doubleway output altogether；

Fig. 4-2, which is shown, is further added by a winding N inside second embodiment_S2, series diode D2 easily obtains not altogether Two-way more than output, equally, the technical solution of Fig. 4-2 is further added by a diode, can obtain three tunnels output, wherein Two tunnels altogether, not altogether with third road；It is further further added by a diode, totally four diodes, can get the output of four tunnels, Altogether, altogether, the first via, the second road and tetra- tunnel third Lu Yu are not altogether on tetra- tunnel third Lu Yu for the middle first via, the second tunnel.

Start-up circuit includes that electric current provides device resistance R1 and capacitor C1, and C1 is the electricity after C11 and C12 series connection in the figure Hold, the one end resistance R1 is to start input terminal, and the other end is starting output end, and capacitor C1 is changed to, same realization in parallel with resistance R1 Purpose of utility model.Resistance R1, or be constant-current source device, the usage of this constant-current source China application No. is 201110200894.5 part has been filled in disclose, and no longer provides explanation here.

3rd embodiment

Fig. 5-1, Fig. 5-2 and Fig. 5-3 are please referred to, is the utility model 3rd embodiment power module main transformer magnetic core three Kind structural schematic diagram, the same the first embodiment or the second embodiment of circuit diagram structure, which is not described herein again.

The utility model of 3rd embodiment is contemplated that the magnetic core of main transformer B1 is made of principal part A and part B, and part is in phase First reach magnetic saturation than the principal part under same ascending magnetic field excitation, in this way, which magnetic core is at work, part is only It is close to or up to local first quartile saturation point or third quadrant saturation point in moment, other time is all in intrinsic first quartile Between saturation point and third quadrant saturation point, since self-excited push-pull type transducer circuit can consume a large amount of energy in core saturation Amount, local magnetic is full to replace all magnetically saturated utility model designs that can efficiency is significantly improved.This magnetic core is in industry Boundary is referred to as Rong Ling magnetic core.The working principle of this part may refer to China application No. is 201110436359.X, 201110436259.7 patent specification.

The A of magnetic core principal part shown in Fig. 5-1 is identical with part B material, and principal part sectional area is greater than partial cross section's product, the part First reach magnetic saturation than the principal part under identical ascending magnetic field excitation.Part at work, only connects in moment Closely or reach local first quartile saturation point or third quadrant saturation point, it is better locally to account for the smaller effect of entire core length；Figure Application No. is the schemes of Fig. 7, Fig. 8 in 201220206952 from China for the magnetic core of 5-1, only gone on magnetic core here two it is convex It rises.

The A of magnetic core principal part shown in Fig. 5-2 and part B material be not identical, and principal part sectional area is less than partial cross section's product, local use The material of high permeability realizes that part first reaches magnetic saturation than principal part under identical ascending magnetic field excitation.Part exists When work, it only is close to or up to local first quartile saturation point or third quadrant saturation point in moment, it is long locally to account for entire magnetic core It is better to spend smaller effect；

The A of magnetic core principal part shown in Fig. 5-3 is identical with local B-section product, and material is different, if local magnetic conductivity is greater than principal part magnetic The material of conductance, i.e. local use more high permeability can also realize part under identical ascending magnetic field excitation than master Portion first reaches magnetic saturation.Part at work, is only close to or up to local first quartile saturation point in moment or third quadrant is full And point, it is better locally to account for the smaller effect of entire core length.Application No. is in 201220206952 from China for the magnetic core of Fig. 5-3 Figure 12 scheme.

The case where circuit gloomy for well for the self-excited push-pull type transducer circuit inside power module, then be driving transformer B1 is three kinds of core structures in Fig. 5-1, Fig. 5-2 and Fig. 5-3, and utility model design is identical, and this will not be repeated here.

Fourth embodiment

Referring to Fig. 6, being the utility model fourth embodiment power module exemplar schematic figure, it is different from the first embodiment it Place is is parallel with capacitor C4 between two collectors for recommending triode, it is therefore intended that elimination recommend triode when powering on because Characteristic frequency is excessively high and generates high-frequency self-excitation, and after increasing capacitor C4, high-frequency self-excitation meeting damped oscillation or frequency of oscillation are moved down, and two Recommend triode just can be entered in the push-pull oscillator carried out using magnetic core saturated characteristic quickly within more than ten of period, realize electricity The quick start on road, in addition high-frequency self-excitation has obtained effective control, and triode is recommended in no longer damage.And it is short to obtain output Road defencive function, working principle is detailed in China, and application No. is 201010604284.7.

The case where being well gloomy circuit for the self-excited push-pull type transducer circuit inside power module, then for in Fig. 1-2 The both ends resistance R2 shunt capacitance C4, meanwhile, the C1 in Fig. 1-2 also to replace with C11 and C12 series connection, it is defeated in main transformer B2 When there is short circuit, because of the presence of C4, the frequency of oscillation of circuit is increased in power module, although in high frequency, driving transformer The efficiency of transmission of B1 reduces, this is also the characteristic of well known Switching Power Supply magnetic core material.Triode TR1 or triode TR2 are obtained Feedback voltage reduce, but after frequency increases, the internal resistance of capacitor C4 reduction compensates for feedback voltage reduction, so that circuit is able to Oscillation is maintained under high frequency.At this moment, main transformer B2 is equally because efficiency of transmission drops lower, loss caused by secondary short circuit, folding Primary side and little is calculated, the operating current of circuit can control in lower range, obtain output short circuit protection function, work Being detailed in China as principle, application No. is the descriptions of the working principle of 201110247645.1 documents, especially 0077 section to 0083 section.

5th embodiment

Fig. 3-6 is please referred to, for the schematic diagram that the utility model power module is applied in the power supply system, the present embodiment application Be first embodiment power module increase all the way vice-side winding obtain independent doubleway output the case where, input filter capacitor C2 With diode D1, D2, output filter capacitor C3 and C5 is designed in its power-supply system by client, be welded on client circuit board it On, since C2 can be the output filter capacitor of upper level Switching Power Supply, without specially installing, thus Fig. 3-6 be not drawn into it is defeated Enter filter capacitor C2.

Above are merely preferred embodiments of the utility model, it is noted that above-mentioned preferred embodiment should not regard For limitations of the present invention.For those skilled in the art, in the essence for not departing from the utility model In mind and range, several improvements and modifications can also be made, the electricity that can such as decline with operating voltage using the capacitance occurred later Hold series connection, substitutes start-up capacitance；Such as start-up capacitance is substituted with three or more capacitor series connection or mixed connection；For another example, in start-up capacitance Series connection low resistance resistance, visiting resistance is 1/5th or less of biasing resistor resistance value；As N-type triode is changed into p-type, In turn supply voltage；Or above-mentioned constant-current source circuit is realized using metal-oxide-semiconductor；And the design of the utility model is applied to Non- self-excited push-pull type transducer circuit and relevant power module and power-supply system, these improvements and modifications also should be regarded as this reality It with novel protection scope, is no longer repeated here with embodiment, the protection scope of the utility model should be limited with claim Subject to fixed range.

Claims (14)

1. a kind of self-excited push-pull type transducer circuit, includes at least: input anode, input ground, start-up circuit, driving part, three Pole pipe TR1 and triode TR2, main transformer B2 and two output ends；Start-up circuit includes at least two terminals, that is, starts Input terminal and starting output end；Driving part includes at least three terminals, i.e. driving input terminal and two drive outputs；Main transformer Depressor B2 includes at least two primary side winding N_P1And N_P2An and vice-side winding N_S1；Start input terminal and connects self-excitation push-pull type The input anode of converter circuit, starting output end connection driving input terminal；The emitter of triode TR1 and triode TR2 are equal With being connected to the input of self-excited push-pull type transducer circuit, collector is separately connected primary side winding N_P1And N_P2Two ends, base Pole is separately connected two drive outputs；Primary side winding N_P1And N_P2Centre cap connection self-excited push-pull type transducer circuit Input anode；Vice-side winding N_S1Both ends connection self-excited push-pull type transducer circuit two output ends；Start-up circuit at least wraps It includes electric current and device and start-up capacitance is provided, it is one of following two that electric current, which provides device and the connection relationship of start-up capacitance:

(1) electric current provides device and start-up capacitance is in parallel, and one end is starting input terminal after parallel connection, the other end is starting output end；

(2) electric current provides device and start-up capacitance series connection, and electric current offer device one end is starting input terminal, the other end is that starting is defeated Outlet, start-up capacitance are connected on electric current and provide between the device other end and the input ground of self-excited push-pull type transducer circuit；

It is characterized by: start-up capacitance includes 2 concatenated capacitors, and 2 concatenated capacitance characteristics be as end voltage increases, Capacitance reduces.

2. self-excited push-pull type transducer circuit according to claim 1, it is characterised in that: 2 concatenated capacitors are chip Multilayer ceramic capacitor.

3. self-excited push-pull type transducer circuit according to claim 1, it is characterised in that: it is resistance that electric current, which provides device, It or is constant-current source device.

4. self-excited push-pull type transducer circuit according to claim 1, it is characterised in that: driving part is to be designed at main transformer Two feedback winding N in depressor B2_B1And N_B2, feedback winding N_B1And N_B2Centre cap be driving input terminal, feedback winding N_B1And N_B2Two ends be two drive outputs.

5. self-excited push-pull type transducer circuit according to claim 4, it is characterised in that: main transformer B2 magnetic core is by principal part With local composition, principal part is identical with local material, and sectional area is different；Or principal part is identical with local sectional area, material is different.

6. self-excited push-pull type transducer circuit according to claim 4, it is characterised in that: triode TR1 and triode TR2 Collector between connect a capacitor.

7. self-excited push-pull type transducer circuit according to claim 6, it is characterised in that: triode TR1 and triode TR2 Collector between the capacitor's capacity that is connected be less than 1000pf.

8. self-excited push-pull type transducer circuit according to claim 1, it is characterised in that: driving part is independent design Driving transformer B1 further includes resistance R2 in driving part, and driving transformer B1 includes primary side winding N_mAnd two feedback around Group N_B1And N_B2, feedback winding N_B1And N_B2Centre cap be driving input terminal, feedback winding N_B1And N_B2Two ends be two A drive output, primary side winding N_mIt connects with resistance R2, two terminals after series connection are respectively connected to triode TR1, TR2 Collector.

9. self-excited push-pull type transducer circuit according to claim 8, it is characterised in that: driving transformer B1 magnetic core is by leading Portion and part composition, principal part is identical with local material, and sectional area is different；Or principal part is identical with local sectional area, material is different.

10. self-excited push-pull type transducer circuit according to claim 8, it is characterised in that: the both ends resistance R2 are one in parallel Capacitor.

11. a kind of power module includes at least four terminals, respectively input plus end, input ground, two output terminals, It is characterized in that: including the described in any item self-excited push-pull type transducer circuits of claims 1 to 10, self-excited push-pull type transducer electricity The input anode on road, input ground and two output ends be correspondingly connected to the input plus end of power module, input and two it is defeated Terminal out.

12. power module according to claim 11, it is characterised in that: further include output rectification circuit in power module.

13. power module according to claim 12, it is characterised in that: do not include in power module input filter capacitor, Output filter capacitor.

14. a kind of power-supply system, it is characterised in that: including external input filter capacitor and output filter capacitor and right It is required that power module described in 12 or 13, input filter capacitor and the input plus end of power module and in parallel, output is inputted Filter capacitor is in parallel with two output terminals of power module, and input filter capacitor and output filter capacitor and power module it Between distance all≤λ/11, λ be power module the corresponding wavelength of working frequency.