CN1055806C - Constant coltage clamped forward switching voltage regulator - Google Patents
Constant coltage clamped forward switching voltage regulator Download PDFInfo
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- CN1055806C CN1055806C CN97103079A CN97103079A CN1055806C CN 1055806 C CN1055806 C CN 1055806C CN 97103079 A CN97103079 A CN 97103079A CN 97103079 A CN97103079 A CN 97103079A CN 1055806 C CN1055806 C CN 1055806C
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Abstract
The present invention relates to a constant voltage clamped forward switch power supply, particularly, a switch power supply which can avoid the saturated problem of a transformer and can reduce the end-point voltage of a main transistor; a constant voltage clamped circuit composed of a voltage sampling circuit, a voltage detection circuit, a synchronous pulse width generator, a constant voltage driving circuit and an energy recovery circuit is arranged in the switch power supply; voltages induced by the secondary winding of the transformer are processed by steps of voltage sampling and detection to generate synchronous pulse width signals corresponding to the switching of the main transistor; the energy recovery circuit generates synchronous action by the voltage driving circuit so that the excitation of the transformer is continuously connected with a diamagnetic current.
Description
The present invention relates to a kind of constant coltage clamped forward switching voltage regulator, mainly provide a kind of deciding the Switching Power Supply of voltage clamp kenel, with solve the transformer magnetic saturation, the main transistor both end voltage is too high and the magnetic saturation problem of input voltage drift and have the advantage of work period to raise the efficiency of increasing.
Switching Power Supply (SWITCHING POWER) now, because no traditional volume is big and the shortcoming of the low-frequency transformer of Heavy Weight, more owing to be under high-frequency operation, and splendid energy efficiency is arranged, so widespread is used as the power supply of computer or as UPS, yet because it is under high-frequency operation, then derive several magnetic saturation, main transistor withstand voltage needs quite high, duty cycle (duty cycle) can't increase and easily produce problem such as action noise, below promptly just now the characteristic of known various Switching Power Supplies illustrate.
As shown in Figure 4, it is forward Switching Power Supply of one " the passive magnetic-type that returns ", this structure is a most basic Switching Power Supply, it has current rectifying and wave filtering circuit 93 one time, transformer 94, secondary current rectifying and wave filtering circuit 95, sampling feedback circuit 91, pulse width controller 92 is formed with main transistor 921, and cross-over connection has the passive magnetic circuit that returns that a diode 941 and resistance 943/ electric capacity 942 are constituted on the elementary winding of transformer 94, by a current rectifying and wave filtering circuit 93 alternating current of sending into is given rectification and filtering, to supply inner required direct current power, and by pulse width controller 92 so that main transistor 921 carries out high frequency ON/OFF (on/off) change action, so that transformer 94 carries out high-frequency excitation, and make its secondary winding position send the high-frequency ac voltage of required voltage value, and then after secondary current rectifying and wave filtering circuit 95 carries out rectifying and wave-filtering, promptly send required direct current power, and in this output end position also by sampling feedback circuit 91 loopbacks one corresponding to the reference voltage of output voltage to pulse width controller 92, make the voltage height numerical value that pulse width controller 92 can present according to output and the duty cycle (DUTY CYCLE) that the ON/OFF of corresponding change main transistor 921 switches, so that output voltage can be stabilized in the fixed voltage value of desire, and the aforementioned passive magnetic circuit that returns that is positioned on the transformer 94 elementary windings, the magnetoelectricity that returns that then can absorb transformer 94 flows, though this structure has simple and work period of circuit can be greater than 50% advantage, but still has following every shortcoming:
(1) power loss is big.
(2) when load change, because the design that this passive type returns magnetic can't reach the defective of dynamic compensation, cause transformer to produce serious saturation current, cause the main transistor two-end-point to produce unusual pulse wave, so main transistor must adopt the withstand voltage element of height can.(shown in the transistor terminal voltage waveform of Fig. 7 (B), having the crest voltage Vp of about supply voltage (B+) more than 2 times to exist).
(3), correspondingly make the peak current of main transistor excessive, for dynamic load difference in response and the excessive shortcoming of noise because transformer has serious saturation current when load change.(shown in the exciting curent (IEX) of Fig. 7 (B), having the peak current Ip above to exist) above power supply saturation current (B SAT).
And as shown in Figure 5, it then is forward Switching Power Supply of one " clamp coil type ", this type of power supply and Fig. 4 difference only are: an auxiliary winding 944 also is set on this transformer 94, and with this auxiliary winding 944 serial connection one diodes 945 and be connected across transformer 94 elementary windings with between the power supply, and auxiliary winding 944 produces an induced current in contrast to the primary winding whereby, reaches the effect of offsetting exciting curent.
And the Switching Power Supply of this clamp coil pattern, have circuit simple, return that magnetic loss is little, unlikely saturated and the little advantage of noise of transformer during dynamic load conditions, but still following shortcoming is arranged:
(1) the withstand voltage aspect of main transistor has to be higher than 2 times and to exist to the end-point voltages of input voltage, so main transistor still need use the high withstand voltage element can.(shown in the transistor end-point voltage waveform of Fig. 7 (C)).
(2) limited under the factor of effective period as the turn ratio of the transformer auxiliary winding of clamp coil by this, the work period of this type of Switching Power Supply is unsuitable for surpassing 50% occasion and uses.
For another shown in Figure 6, it then is forward Switching Power Supply of one " dynamically clamp formula ", its difference is to be provided with a delay circuit 96, one extra transformer 97 and one and the clamping transistor 98 that is connected in parallel of main transformer 94 elementary windings, and can make these clamping transistor 98 in good time conductings according to the operate condition of supply voltage, pulse width controller 92 and end, return the effect of magnetoelectricity stream to reach dynamic absorption.
Though yet that this design has the magnetic loss of returning is little and can make the work period greater than 75%, increase magnetic flux density and when heavy duty, have high efficiency advantage, yet its main transistor also need use high withstand voltage element, it is also quite big that main transistor bears peak current, and when load change, serious saturated phenomenon (shown in transistor end points (V DS) waveform and exciting curent (I EX) of Fig. 7 (D)) is also arranged, and this clamping transistor 98 also bears the saturation peak electric current that is same as main transistor 921, and the big shortcoming of noise is arranged because of saturation problem, more because this clamping transistor has the A.C. losses factor, under light-load state, efficient is the most low, can't meet complete dynamic power supply supply effect.
Since aforementioned no matter be passive return magnetic-type, clamp coil type or dynamically the clamp formula forward Switching Power Supply have respectively and must use high withstand voltage element, can't be applicable to simultaneously that light, heavy duty is used, operating noise is big, transformer is saturated and the shortcoming of work period limited (work period can't be given extension again), so have and give improved necessity again.
Main purpose of the present invention is to provide a kind of constant coltage clamped forward switching voltage regulator, it has good dynamic load response, can use the transistor unit that hangs down withstand voltage and reduced-current, no clamping transistor A.C. losses, the low operating noise of tool reaches than long-time cycle.
Technical program of the present invention lies in providing a kind of constant coltage clamped forward switching voltage regulator, by once/secondary current rectifying and wave filtering circuit, a sampling feedback circuit, a pulse width controller, a main switching transistor and a main transformer constitute the forward basic circuit of Switching Power Supply, its characteristics are:
Between the elementary winding of this current rectifying and wave filtering circuit and main transformer the certain voltage clamp circuit is set, this is decided voltage clamping circuit and comprises:
One voltage sample circuit is obtained induced voltage on the auxiliary winding by transformer, and can be exchanged into positive and negative to peak voltage signal,
One synchronous pulse-width modulation circuit can produce the output signal of a corresponding square wave pulse width variations according to the high-low level of the crest voltage of sending into,
The certain voltage drive circuit receives above-mentioned square wave pulse width signal and is converted to the electric current amplifying signal, and the maximum of restriction electric current amplifying signal,
One energy recovering circuit, be serially connected with between the elementary winding of current rectifying and wave filtering circuit and main transformer, can receive and decide the electric current amplifying signal that Voltag driving circuit is sent into, and absorb the magnetic energy that returns of main transformer generation with on-off mode, and be converted to supplying energy according to this signal.
Above-mentioned constant coltage clamped forward switching voltage regulator, its characteristics are: this voltage sample circuit comprises forward peak value and negative peak diode and capacitor, described two diodes are connected in series, it connects the end that mid point is connected to the auxiliary winding of described transformer, an end separately of described two capacitors is connected respectively to described two diodes, and the other end of described two capacitors is also received the other end of described auxiliary winding.
Above-mentioned constant coltage clamped forward switching voltage regulator, its characteristics are: this synchronous pulse-width modulation circuit comprises voltage detecting circuit that is connected with described voltage sample circuit and the synchronous pulse width generator that is connected and is subjected to its control with this voltage detecting circuit.
Above-mentioned constant coltage clamped forward switching voltage regulator, its characteristics are: this voltage detecting circuit comprises the certain current circuit that is made of Zener diode, three resistance (R1, R2, R3) and a transistor, wherein the Zener diode two ends are connected respectively to the two ends of aforementioned auxiliary winding, and a wherein end of Zener diode is connected to described transistorized base stage by resistance (R3), and described transistorized collector electrode is connected with synchronous pulse width generator;
Described resistance (R1) and (R3) be connected to described transistorized base stage jointly with an end separately, wherein the other end of resistance (R1) is connected to an end of resistance (R2), and the other end of resistance (R2) is connected to described transistorized emitter.
Above-mentioned constant coltage clamped forward switching voltage regulator, its characteristics are: this synchronous pulse width generator comprises that at least a capacitor and is connected to electric current amplifier transistor on described auxiliary winding one end with base stage; Wherein, an end of this capacitor is connected to the same end of described auxiliary winding, and the other end of this capacitor is connected with the transistorized collector electrode of voltage detecting circuit, the collector electrode of described electric current amplifier transistor with decide Voltag driving circuit and be connected.
Above-mentioned constant coltage clamped forward switching voltage regulator, its characteristics are: this synchronous pulse width generator is by the peak forward voltage control of described auxiliary winding induction.
Above-mentioned constant coltage clamped forward switching voltage regulator, its characteristics are: this is decided Voltag driving circuit and comprises an electric current amplifier transistor that is connected with the synchronous output of pulse width generator with base stage at least, and the emitter of this electric current amplifier transistor is connected with energy recovering circuit.
Above-mentioned constant coltage clamped forward switching voltage regulator, its characteristics are: this is decided Voltag driving circuit and be provided with a Zener diode on the base stage of its electric current amplifier transistor, the negative pole of this Zener diode is connected with the base stage of described electric current amplifier transistor, its positive pole is connected to an end of described auxiliary winding, to limit the output level that this decides Voltag driving circuit.
Above-mentioned constant coltage clamped forward switching voltage regulator, its characteristics are: this energy recovering circuit comprises that at least is connected in diode between the primary winding and capacitor, certain voltage driving transistors, a coil that magnetizes; Wherein:
Described diode and capacitor are connected respectively to the two ends of described elementary winding with an end separately, and the other end of described diode and capacitor interconnects and be connected to the source electrode of deciding voltage drive transistor;
The described grid of deciding voltage drive transistor is connected with the output of deciding Voltag driving circuit, its leakage level is connected with an output of magnetize a coil and a current rectifying and wave filtering circuit simultaneously, and the other end of the coil that magnetizes is connected with another output of a current rectifying and wave filtering circuit.
Design features of the present invention provides a kind ofly can respond to the forward excitatory state of power supply synchronously, and by voltage detecting circuit 30, change synchronous pulse width generator 40 with the variation that detects input voltage and can produce corresponding pulsewidth current drive signal, and utilize and to decide Voltag driving circuit 50 and make energy recovering circuit 60 do the energy recuperation of dynamic, so not only can reach rapidly and positively absorb the effect of returning magnetic energy, and make it no matter gently, the situation of heavy duty or input voltage change all can be exempted the magnetically saturated problem of transformer, and pass through it and decide the design of voltage clamp, the elementary winding of limiting transformer two ends unlikely generation peak value excessive variation and acquisition more positively reduces the effect of main switching transistor end-point voltage and peak current, so decide voltage clamp design with of the present invention, have following every advantage:
(1) has good dynamic load response, when the load dynamic change, because all can give elasticity and positively make zero by decide voltage clamping circuit at the exciting curent in each cycle, even if under the occasion that input voltage changes, transformer all can not cause saturated phenomenon.
(2) because inside is to adopt the design of deciding voltage clamp, and the coil-end of transformer and main transistor end-point voltage are low, and do not have excessive peak-to-peak value electric current generation, can use the transistor unit that hangs down withstand voltage and reduced-current.
(3) there is no the forward exchange that clamping transistor the caused loss of Switching Power Supply of existing dynamic clamp formula, no matter under underload or heavy duty state, high efficiency advantage is arranged all.
(4) because transformer does not all have the magnetic saturation problem in light, heavy duty and input voltage variation, so all lower in the operation noise of various occasions.
(5) work period there is no the restriction of existing change-over circuit, can do pulsewidth adjustment by a relatively large margin in effective period, and its work period can be greater than 75%.
Therefore, the present invention promptly decides the design of the forward Switching Power Supply of voltage clamp pattern with it, really can solve input voltage change, light/transformer saturation problem that heavy duty change occasion is derived effectively, more can use the transistor unit of low rated voltage.
Further specify specific structural features of the present invention and purpose below in conjunction with accompanying drawing.
Fig. 1 is a circuit diagram of the present invention.
Fig. 2 is that Fig. 1 indicates each end points and adds the schematic diagram that electric current indicates.
Fig. 3 is voltage, the current waveform schematic diagram at each position of Fig. 1.
Fig. 4 is the existing passive forward circuit diagram of Switching Power Supply of magnetic-type that returns.
Fig. 5 is the forward circuit diagram of Switching Power Supply of existing clamp coil type.
Fig. 6 is the forward circuit diagram of Switching Power Supply of existing dynamic clamp formula.
Fig. 7 is the comparison diagram of voltage, current waveform and the magnetic saturation phenomenon of the present invention and various existing Switching Power Supplies under the dynamic load.
As shown in Figure 1, of the present inventionly decide forward Switching Power Supply textural of voltage clamp formula, also have equally once/secondary current rectifying and wave filtering circuit 10,11, transformer T1, sampling feedback circuit 12, pulse width controller 13, the switching switch circuit 14 that constitutes with main switching transistor Q5, constituting the forward basic circuit of Switching Power Supply, and difference of the present invention be:
Have a synchronous pulse-width modulation circuit of being formed with voltage sample circuit 20, a voltage detecting circuit 30 and a synchronous pulse width generator 40, certain voltage drive circuit 50 and an energy recovering circuit 60 common certain voltage clamp circuits of forming, so that having, whole forward Switching Power Supply do not cause transformer saturated, withstand voltage that reduces transistor Q5 and the effect that reduces the peak-to-peak value electric current, and no matter under the high and low load condition or the situation of external input voltage change, good work efficiency is all arranged, below promptly successively with regard to every structure and the effect analyzed.
This voltage sample circuit 20, be that auxiliary winding N3, two diode D2, D4 and two capacitor C 2, C5 with transformer T1 formed, and the voltage of the formed positive and negative peak value of this auxiliary winding N3 can be stored in two capacitor C 2, C5 endpoint location respectively, reach generation whereby corresponding to negative sense under the transformer T1 operating state or peak forward voltage state, and the voltage value that this voltage sample circuit 20 is sent height, then can utilize the elementary winding N1 of transformer T1 and the turn ratio of auxiliary winding N3 to be adjusted, it can be corresponded to actual needs.
The voltage detecting circuit 30 of this synchronous pulse-width modulation circuit is formed with a Zener diode ZD1, resistance R 1, R2, R3 and transistor Q1, can detect the capacitor C 2 of voltage sample circuit 20, the variable quantity of C5 end-point voltage to form one, and be converted to current change quantity, and utilize the follow-up synchronous pulse width generator 40 of transistor Q1 control.
The synchronous pulse width generator 40 of this synchronous pulse-width modulation circuit is with diode D3, resistance R 4, R5, a capacitor C 4 and a transistor Q2 form, this synchronous pulse width generator 40 is directly to be connected with the transformer T1 auxiliary winding N3 of voltage sample circuit 20 by diode D3, and an end of this capacitor C 4 is connected with the transistor Q1 collector electrode of voltage detecting circuit 30, these structures can be when auxiliary winding N3 produces induced voltage, wherein induced electricity positive pressure half cycle signal can be through 4 chargings of 4 pairs of capacitor C of resistance R, the transistor Q1 of voltage detecting circuit 30 then can change according to the height of the voltage value of sending into this capacitor C 4 is carried out constant-current discharge, this discharges and recharges action, and Fig. 2 is somebody's turn to do with respect to resistance R 4, voltage (V between the outer end points E-C of capacitor C 4
E-C) (cooperating the respective waveforms as Fig. 3 stage casing) presents the waveform effect synchronous with transformer T1, and this E-C point voltage promptly promotes this transistor Q2 through resistance R 5, produces the square wave output with the sampling voltage variation with the collector electrode at this transistor Q2.
Should decide Voltag driving circuit 50 is made up of a Zener diode ZD2, diode D5, resistance R 7 and transistor Q4, this Zener diode ZD2 is the maximum voltage value in order to the transistor Q2 square wave output that limits aforementioned synchronous pulse width generator 40, so that the voltage clamp effect to be provided, and this diode D5 is base, emitter voltage in order to limit transistor Q4, and can be phase inversion system operation along with the square-wave signal of aforementioned transistor Q2, and promote follow-up energy recovering circuit 60 according to this decide voltage drive transistor Q3.
This energy recovering circuit 60 is to comprise certain voltage driving transistors Q3, the one coil L1 that magnetizes, two diode D1,6 common compositions of D6 and capacitor C, the effect of this circuit is the excitatory energy of transformer T1 can be stored in the capacitor C 6 through diode D6, and then when being synchronous ON (conducting)/OFF (ending) action by deciding voltage drive transistor Q3 to be subjected to the aforementioned control of deciding voltage clamping circuit that forms, then the energy that is stored in capacitor C 6 can be transferred on the coil L1 that magnetizes through deciding voltage drive transistor Q3, be to return magnetic energy through capacitor C 1 charging of diode D1 at last to the upper left current rectifying and wave filtering circuit 10 of drawing by this coil L1 that magnetizes, to form a kind of break-even magnetic action of returning, and this energy recovering circuit 60 also limits the peak-peak voltage at the elementary winding N1 two ends of this transformer T1, so, then can make transformer T1 no matter under underload or heavy duty situation, still have good magnetic effect and the unlikely magnetic saturation phenomenon that causes returned.(and the voltage at each working point of this circuit and each position, electric current change circuit diagram and oscillogram that the sign that can cooperate Fig. 2 and Fig. 3 has each end points and correlated current.)
And the present invention also can be under the situation of input voltage change, also because the present invention adopts the design of deciding voltage clamp, and can not cause saturated problem, surpass last and cooperate as the leading portion of Fig. 3 and the input voltage (VA-M) of back fragment position, during the lower position, the state that can present complete conducting or end fully then by the Zener diode ZD1 of this voltage detecting circuit 30 of Fig. 1, so that the capacitor C of pulse width generator 40 inside prolongs and shortens 4 discharge times synchronously, and when input voltage is too high, for the transistor Q1 that makes voltage detecting circuit 30 is complete conducting, and make that Fig. 2 should be corresponding to resistance R 4 two-end-point B, E just, negative pulsewidth is just to be same as the elementary winding N1 of transformer T1, negative pulsewidth, therefore, the switch periods of deciding voltage drive transistor Q3 promptly is equal to the switch periods of main switching transistor Q5, the exciting curent I6 of the transformer T1 of Fig. 2 is equal to returns magnetoelectricity stream I5, and for being equal to the electric current I 4 that magnetizes of the coil L1 that magnetizes, when if this inductance value that magnetizes coil L1 is made as the inductance value that is equal to the elementary winding N1 of transformer T1, even capacitor C 6 is just identical with the energy that capacitor C 1 was obtained in the unlatching cycle (ONCYCLE) in the energy in the cycle of closing (OFFCYCLE), as previously mentioned, not only can make the elementary winding N1 of transformer T1 end points present square-wave waveform, and the coil L1 two ends of magnetizing also are square-wave waveform, and exciting curent and return magnetoelectricity stream and be the state that joins continuously just, and magnetizing and returning magnetoelectricity stream of the coil L1 that magnetizes also joined continuously for being, and do not have the magnetic saturation problem so can make transformer T1 still can remain on the normal running situation and exists.
Claims (9)
1. constant coltage clamped forward switching voltage regulator, by once/secondary current rectifying and wave filtering circuit, a sampling feedback circuit, a pulse width controller, a main switching transistor and a main transformer constitute the forward basic circuit of Switching Power Supply, it is characterized in that:
Between the elementary winding of this current rectifying and wave filtering circuit and main transformer the certain voltage clamp circuit is set, this is decided voltage clamping circuit and comprises:
One voltage sample circuit is obtained induced voltage on the auxiliary winding by transformer, and can be exchanged into positive and negative to peak voltage signal,
One synchronous pulse-width modulation circuit can produce the output signal of a corresponding square wave pulse width variations according to the high-low level of the crest voltage of sending into,
The certain voltage drive circuit receives above-mentioned square wave pulse width signal and is converted to the electric current amplifying signal, and the maximum of restriction electric current amplifying signal,
One energy recovering circuit, be serially connected with between the elementary winding of current rectifying and wave filtering circuit and main transformer, can receive and decide the electric current amplifying signal that Voltag driving circuit is sent into, and absorb the magnetic energy that returns of main transformer generation with on-off mode, and be converted to supplying energy according to this signal.
2. constant coltage clamped forward switching voltage regulator according to claim 1, it is characterized in that: this voltage sample circuit comprises forward peak value and negative peak diode and capacitor, described two diodes are connected in series, it connects the end that mid point is connected to the auxiliary winding of described transformer, an end separately of described two capacitors is connected respectively to described two diodes, and the other end of described two capacitors is also received the other end of described auxiliary winding.
3. constant coltage clamped forward switching voltage regulator according to claim 1 is characterized in that: this synchronous pulse-width modulation circuit comprises voltage detecting circuit that is connected with described voltage sample circuit and the synchronous pulse width generator that is connected and is subjected to its control with this voltage detecting circuit.
4. constant coltage clamped forward switching voltage regulator according to claim 3, it is characterized in that: this voltage detecting circuit comprises the certain current circuit that is made of Zener diode, three resistance (R1, R2, R3) and a transistor, wherein the Zener diode two ends are connected respectively to the two ends of aforementioned auxiliary winding, and a wherein end of Zener diode is connected to described transistorized base stage by resistance (R3), and described transistorized collector electrode is connected with synchronous pulse width generator;
Described resistance (R1) and (R3) be connected to described transistorized base stage jointly with an end separately, wherein the other end of resistance (R1) is connected to an end of resistance (R2), and the other end of resistance (R2) is connected to described transistorized emitter.
5. according to claim 3 or 4 described constant coltage clamped forward switching voltage regulators, it is characterized in that: this synchronous pulse width generator comprises that at least a capacitor and is connected to electric current amplifier transistor on described auxiliary winding one end with base stage; Wherein, an end of this capacitor is connected to the same end of described auxiliary winding, and the other end of this capacitor is connected with the transistorized collector electrode of voltage detecting circuit, the collector electrode of described electric current amplifier transistor with decide Voltag driving circuit and be connected.
6. constant coltage clamped forward switching voltage regulator according to claim 5 is characterized in that: this synchronous pulse width generator is by the peak forward voltage control of described auxiliary winding induction.
7. constant coltage clamped forward switching voltage regulator according to claim 1, it is characterized in that: this is decided Voltag driving circuit and comprises an electric current amplifier transistor that is connected with the synchronous output of pulse width generator with base stage at least, and the emitter of this electric current amplifier transistor is connected with energy recovering circuit.
8. constant coltage clamped forward switching voltage regulator according to claim 7, it is characterized in that: this is decided Voltag driving circuit and be provided with a Zener diode on the base stage of its electric current amplifier transistor, the negative pole of this Zener diode is connected with the base stage of described electric current amplifier transistor, its positive pole is connected to an end of described auxiliary winding, to limit the output level that this decides Voltag driving circuit.
9. constant coltage clamped forward switching voltage regulator according to claim 1 is characterized in that: this energy recovering circuit comprises that at least is connected in diode between the primary winding and capacitor, certain voltage driving transistors, a coil that magnetizes; Wherein:
Described diode and capacitor are connected respectively to the two ends of described elementary winding with an end separately, and the other end of described diode and capacitor interconnects and be connected to the source electrode of deciding voltage drive transistor;
The described grid of deciding voltage drive transistor is connected with the output of deciding Voltag driving circuit, its leakage level is connected with an output of magnetize a coil and a current rectifying and wave filtering circuit simultaneously, and the other end of the coil that magnetizes is connected with another output of a current rectifying and wave filtering circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN97103079A CN1055806C (en) | 1997-03-20 | 1997-03-20 | Constant coltage clamped forward switching voltage regulator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN97103079A CN1055806C (en) | 1997-03-20 | 1997-03-20 | Constant coltage clamped forward switching voltage regulator |
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| Publication Number | Publication Date |
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| CN1194494A CN1194494A (en) | 1998-09-30 |
| CN1055806C true CN1055806C (en) | 2000-08-23 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN97103079A Expired - Fee Related CN1055806C (en) | 1997-03-20 | 1997-03-20 | Constant coltage clamped forward switching voltage regulator |
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Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6396716B1 (en) * | 2001-09-20 | 2002-05-28 | The University Of Hong Kong | Apparatus for improving stability and dynamic response of half-bridge converter |
| CN100388148C (en) * | 2002-10-31 | 2008-05-14 | 中兴通讯股份有限公司 | Circuit for regulating lower limit of limiting switch power source voltage |
| CN102739025A (en) * | 2011-04-11 | 2012-10-17 | 深圳市英可瑞科技开发有限公司 | Switch power supply protection control circuit |
| CN103001506A (en) * | 2012-11-13 | 2013-03-27 | 东莞市威力固电路板设备有限公司 | Power source circuit for circuit board blind hole electroplating |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1015848B (en) * | 1989-05-29 | 1992-03-11 | 三菱电机株式会社 | Pwm conversion apparatus |
| CN1092345A (en) * | 1993-03-17 | 1994-09-21 | 哈尔滨工业大学 | Pulse width modulating electric spark working pulse power source |
-
1997
- 1997-03-20 CN CN97103079A patent/CN1055806C/en not_active Expired - Fee Related
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1015848B (en) * | 1989-05-29 | 1992-03-11 | 三菱电机株式会社 | Pwm conversion apparatus |
| CN1092345A (en) * | 1993-03-17 | 1994-09-21 | 哈尔滨工业大学 | Pulse width modulating electric spark working pulse power source |
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| CN1194494A (en) | 1998-09-30 |
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