CN108322051A - A kind of inverse-excitation type switch power-supply - Google Patents

Abstract

The invention discloses a kind of inverse-excitation type switch power-supplies, including input rectifying filter circuit, control circuit, high frequency transformer, output rectifier and filter and the current feedback circuit being sequentially connected, input rectifying filter circuit is used to the alternating current of input being changed into direct current, control circuit is used to be converted in direct current the square wave of required voltage value, high frequency transformer is used to adjust the size of voltage, and square-wave voltage for being changed into required DC voltage by output rectifier and filter；Control circuit is connected with input rectifying filter circuit, high frequency transformer and current feedback circuit respectively, and high frequency transformer exports DC voltage through output rectifier and filter, and high frequency transformer is also connected with current feedback circuit.The present invention can adjust the size of output voltage, improve the frequency and efficiency of Switching Power Supply, and when overcurrent occurs for Switching Power Supply, and switching tube shutdown is realized the protection of switch tube, run with making load stabilization.

Description

A kind of inverse-excitation type switch power-supply

Technical field

The present invention relates to field of switch power more particularly to a kind of inverse-excitation type switch power-supplies.

Background technology

Switching Power Supply has outstanding advantages of energy consumption is small, efficient, voltage stabilized range is wide, small and light-weight, is communicatingIt is widely applied in the electronic circuits such as equipment, numerical control device, instrument, audio-visual devices and household electrical appliance.Switching Power SupplyTypical structure has tandem tap power supply architecture, paralleling switch power supply architecture, positive exciting switching voltage regulator structure, reverse exciting switching voltage regulator knotStructure, half-bridge switch power source structure and full-bridge switching power supply structure, wherein reverse exciting switching voltage regulator circuit is simple, and output voltage both may be usedIt can be less than input voltage again higher than input voltage, apply in general in output power 200W Switching Power Supplies below.It is existingSwitching Power Supply generally uses voltage-type pulse width modulator, but the frequency response of voltage-type pulse width modulator is slower, voltage regulation factor andLoad regulation is relatively low, to make the less efficient of Switching Power Supply.

Invention content

The purpose of the present invention is to provide a kind of inverse-excitation type switch power-supplies, can improve the frequency and efficiency of Switching Power Supply,It runs with making load stabilization.

To achieve the above object, the present invention adopts the following technical scheme that：

A kind of inverse-excitation type switch power-supply, including the input rectifying filter circuit, control circuit, high frequency transformer, defeated that is sequentially connectedGoing out current rectifying and wave filtering circuit and current feedback circuit, input rectifying filter circuit is used to the alternating current of input being changed into direct current,Control circuit is used to be converted in direct current the square wave of required voltage value, and high frequency transformer is used to adjust the size of voltage, outputCurrent rectifying and wave filtering circuit is used for for square-wave voltage to be changed into required DC voltage, feedback circuit according to the defeated of high frequency transformerGo out the output waveform that voltage carrys out adjusting pulsewidth modulation module, to adjust the size of output voltage；The control circuit uses arteries and veinsWidth modulation chip, pulse width modulating chip is connected with input rectifying filter circuit, high frequency transformer and current feedback circuit respectively, highFrequency power transformer exports DC voltage through output rectifier and filter, and high frequency transformer is also connected with current feedback circuit.

Preferably, the input rectifying filter circuit includes electromagnetic interface filter and bridge rectifier, and electromagnetic interface filter includesFirst capacitance and rectifier transformer, alternating voltage are connected through the first capacitance with the primary side of rectifier transformer, the pair of rectifier transformerWhile be connected with the input terminal of bridge rectifier through the second capacitance, the first output end and second output terminal point of bridge rectifierIt is not connected with pulse width modulating chip.

Preferably, 7 pins of the pulse width modulating chip are successively through the first potentiometer and first resistor and bridge rectifier electricityFirst output end on road is connected, and 7 pins of pulse width modulating chip are also connected with the second output terminal of bridge rectifier, pulsewidth tune2 pins of coremaking piece are connected through second resistance with 7 pins of pulse width modulating chip, and 1 pin of pulse width modulating chip is through third electricityResistance is connected with 2 pins of pulse width modulating chip, and the both ends of 3rd resistor are parallel with third capacitance, 8 pins of pulse width modulating chipIt is connected with 2 pins of pulse width modulating chip, 4 pins of 8 pins through the 4th resistance and pulse width modulating chip of pulse width modulating chipIt is connected, for 8 pins of pulse width modulating chip also through the 5th resistance eutral grounding, the 5th resistance both ends are parallel with the 4th capacitance, pulsewidth modulation4 pins of chip through the 5th capacity earth, 3 pins and 6 pins of the pulse width modulating chip respectively with current feedback circuit phaseEven；

The current feedback circuit includes the 6th capacitance being connected with 3 pins of pulse width modulating chip, the 6th capacity earth, pulsewidth3 pins of modulation chip are also connected with the 6th resistance, the 6th resistance through the 7th resistance eutral grounding, the 6th resistance also with first switch pipeSource electrode be connected, the grid of first switch pipe is connected through the 8th resistance with 6 pins of pulse width modulating chip, the leakage of first switch pipeThe first diode of pole is connected with 7 pins of pulse width modulating chip, first switch pipe drain electrode also with the primary side of high frequency transformerIt is connected.

Preferably, the pulse width modulating chip uses UC3842 current source PWM chips.

Preferably, one end of the primary side of the high frequency transformer is connected with the first output end of bridge rectifier, high frequencyOne end of the primary side of transformer is also connected through the 7th capacitance and the second diode with the other end of the primary side of high frequency transformer successively,7th capacitance both ends are parallel with the 9th resistance, high frequency transformer first it is secondary while and second it is secondary while be separately connected output rectification filterCircuit.

Preferably, the output rectifier and filter includes the first current rectifying and wave filtering circuit and the second current rectifying and wave filtering circuit, theOne current rectifying and wave filtering circuit and current rectifying and wave filtering circuit respectively with the first of high frequency transformer it is secondary while and second it is secondary while be connected, the first rectificationFilter circuit includes the third diode and the 8th capacitance being connected with the first secondary side of high frequency transformer, third diode and the 8thThe common end of capacitance is connected through the first inductance and the 9th capacitance with the first secondary side of high frequency transformer successively, the both ends of the 9th capacitanceFirst voltage is exported, the second current rectifying and wave filtering circuit includes the 4th diode and the tenth being connected with the second secondary side of high frequency transformerThe common end of capacitance, the 4th diode and the tenth capacitance successively through the second inductance and the 11st capacitance and high frequency transformer firstSecondary side is connected, and the both ends of the 11st capacitance export second voltage.

The alternating current of input is changed into direct current by the present invention by input rectifying filter circuit, then passes through control circuitThe square wave that direct current is converted to required voltage value with high frequency transformer, finally by output rectifier and filter by square-wave voltageIt is changed into required DC voltage, input rectifying filter circuit can effectively inhibit the electromagnetic interference of Switching Power Supply, improve switchThe efficiency of power supply, current feedback circuit can be according to the output voltages of high frequency transformer come the output wave of adjusting pulsewidth modulation moduleShape, to adjust the size of output voltage, current feedback circuit can also be detected the electric current of output rectifier and filter,When overcurrent occurs for Switching Power Supply, switching tube shutdown is realized the protection of switch tube, is run with making load stabilization.

Description of the drawings

Fig. 1 is the circuit diagram of the present invention；

Fig. 2 is the circuit diagram of current feedback circuit of the present invention.

Specific implementation mode

Technical scheme of the present invention is clearly and completely described below in conjunction with attached drawing, it is clear that described embodimentOnly section Example of the invention, instead of all the embodiments.Based on the embodiments of the present invention, the common skill in this fieldOther all embodiments that art personnel are obtained without making creative work belong to the protection model of the present inventionIt encloses.

As shown in Figures 1 and 2, a kind of inverse-excitation type switch power-supply of the present invention, including the input rectifying that is sequentially connectedFilter circuit, control circuit, high frequency transformer, output rectifier and filter and current feedback circuit, input rectifying filter circuitFor the alternating current of input to be changed into direct current, control circuit is used to be converted in direct current the square wave of required voltage value, highFrequency power transformer is used to adjust the size of voltage, and square-wave voltage for being changed into required direct current by output rectifier and filterPressure, feedback circuit are used for the output voltage according to high frequency transformer come the output waveform of adjusting pulsewidth modulation module, to adjustThe size of output voltage；Control circuit use pulse width modulating chip, pulse width modulating chip respectively with input rectifying filter circuit, heightFrequency power transformer and current feedback circuit are connected, and high frequency transformer exports DC voltage, high frequency transformation through output rectifier and filterDevice is also connected with current feedback circuit.

Input rectifying filter circuit includes electromagnetic interface filter and bridge rectifier VD1, and electromagnetic interface filter includes the first capacitanceC1 and rectifier transformer T1, alternating voltage are connected through the first capacitance C1 with the primary side of rectifier transformer T1, rectifier transformer T1'sSecondary side the second capacitance C2 is connected with the input terminal of bridge rectifier VD1, the first output end of bridge rectifier VD1 andTwo output ends are connected with pulse width modulating chip IC1 respectively.

In the present embodiment, pulse width modulating chip IC1 uses UC3842 current source PWM chips, pulse width modulating chipThe DC power supply feeder ear of IC1（7 pins）Successively through the first potentiometer RP1's and first resistor R1 and bridge rectifier VD1First output end is connected, the DC power supply feeder ear of pulse width modulating chip IC1（7 pins）Also with the of bridge rectifier VD1Two output ends are connected, the feedback voltage input terminal of pulse width modulating chip IC1（2 pins）Through second resistance R2 and pulse width modulating chipThe DC power supply feeder ear of IC1（7 pins）It is connected, the error amplifier output of pulse width modulating chip IC1（1 pin）Through thirdThe feedback voltage input terminal of resistance R3 and pulse width modulating chip IC1（2 pins）It is connected, the both ends of 3rd resistor R3 are parallel with thirdCapacitance C3, the reference voltage output end of pulse width modulating chip IC1（8 pins）It is inputted with the feedback voltage of pulse width modulating chip IC1End（2 pins）It is connected, the reference voltage output end of pulse width modulating chip IC1（8 pins）Through the 4th resistance R4 and pulsewidth modulation coreThe timing end of piece IC1（4 pins）It is connected, the reference voltage output end of pulse width modulating chip IC1（8 pins）Also through the 5th resistance R5Ground connection, the 5th both ends resistance R5 are parallel with the 4th capacitance C4, the timing end of pulse width modulating chip IC1（4 pins）Through the 5th capacitanceC5 is grounded, the current sense input of pulse width modulating chip IC1（3 pins）With recommending output mode end（6 pins）It is anti-with electric current respectivelyCurrent feed circuit is connected.

Current feedback circuit includes the current sense input with pulse width modulating chip IC1（3 pins）The 6th connected electricityHold C6, the 6th capacitance C6 ground connection, the current sense input of pulse width modulating chip IC1（3 pins）Also it is connected with the 6th resistance R6,6th resistance R6 is also connected with the source electrode of first switch pipe Q1 through the 7th resistance R7 ground connection, the 6th resistance R6, first switch pipe Q1Recommending output mode end of the grid through the 8th resistance R8 Yu pulse width modulating chip IC1（6 pins）It is connected, the drain electrode of first switch pipe Q1DC power supply feeder ear through the first diode D1 Yu pulse width modulating chip IC1（7 pins）It is connected, the drain electrode of first switch pipe Q1Also it is connected with the primary side of high frequency transformer T2.

One end of the primary side of high frequency transformer T2 is connected with the first output end of bridge rectifier VD1, high frequency transformerOne end of the primary side of T2 also other end phase through the 7th capacitance C7 and the second diode D2 and the primary side of high frequency transformer T2 successivelyEven, the 7th both ends capacitance C7 are parallel with the 9th resistance R9, high frequency transformer T2 first it is secondary while and second it is secondary while be separately connected it is defeatedGo out current rectifying and wave filtering circuit.

Output rectifier and filter includes the first current rectifying and wave filtering circuit and the second current rectifying and wave filtering circuit, the first rectifying and wave-filtering electricityRoad and current rectifying and wave filtering circuit respectively with the first of high frequency transformer T2 it is secondary while and second it is secondary while be connected, the first current rectifying and wave filtering circuit packetInclude the third diode D3 and the 8th capacitance C8 being connected with the first secondary side of high frequency transformer T2, the electricity of third diode D3 and the 8thThe common end for holding C8 is connected through the first inductance L1 and the 9th capacitance C9 with the first secondary side of high frequency transformer T2 successively, the 9th capacitanceThe both ends of C9 export first voltage OUT1, and the second current rectifying and wave filtering circuit includes the to be connected with the second secondary side of high frequency transformer T2The common end of four diode D4 and the tenth capacitance C10, the 4th diode D4 and the tenth capacitance C10 are successively through the second inductance L2 and11 capacitance C11 are connected with the first secondary side of high frequency transformer T2, the both ends output second voltage OUT2 of the 11st capacitance C11.

The present invention can adjust the size of output voltage, improve the frequency and efficiency of Switching Power Supply, and when Switching Power Supply is sent outWhen raw overcurrent, switching tube shutdown is realized the protection of switch tube, is run with making load stabilization.

Claims (6)

1. a kind of inverse-excitation type switch power-supply, it is characterised in that：Including be sequentially connected input rectifying filter circuit, control circuit,High frequency transformer, output rectifier and filter and current feedback circuit, the alternating current that input rectifying filter circuit is used to inputIt is changed into direct current, control circuit is used to be converted in direct current the square wave of required voltage value, and high frequency transformer is for adjusting electricityThe size of pressure, output rectifier and filter are used for basis for square-wave voltage to be changed into required DC voltage, feedback circuitThe output voltage of high frequency transformer carrys out the output waveform of adjusting pulsewidth modulation module, to adjust the size of output voltage；It is describedControl circuit use pulse width modulating chip, pulse width modulating chip respectively with input rectifying filter circuit, high frequency transformer and electric currentFeedback circuit be connected, high frequency transformer through output rectifier and filter export DC voltage, high frequency transformer also with current feedbackCircuit is connected.

2. a kind of inverse-excitation type switch power-supply as described in claim 1, it is characterised in that：The input rectifying filter circuit includesElectromagnetic interface filter and bridge rectifier, electromagnetic interface filter include the first capacitance and rectifier transformer, and alternating voltage is through the first capacitanceIt is connected with the primary side of rectifier transformer, the second capacitance of secondary side of rectifier transformer is connected with the input terminal of bridge rectifier,The first output end and second output terminal of bridge rectifier are connected with pulse width modulating chip respectively.

3. a kind of inverse-excitation type switch power-supply as claimed in claim 2, it is characterised in that：7 pins of the pulse width modulating chipIt is connected successively with the first output end of bridge rectifier through the first potentiometer and first resistor, 7 pins of pulse width modulating chipAlso it is connected with the second output terminal of bridge rectifier, 2 pins of pulse width modulating chip are through second resistance and pulse width modulating chip7 pins be connected, 1 pin of pulse width modulating chip is connected through 3rd resistor with 2 pins of pulse width modulating chip, 3rd resistorBoth ends are parallel with third capacitance, and 8 pins of pulse width modulating chip are connected with 2 pins of pulse width modulating chip, pulse width modulating chip8 pins be connected with 4 pins of pulse width modulating chip through the 4th resistance, 8 pins of pulse width modulating chip also connect through the 5th resistanceGround, the 5th resistance both ends are parallel with the 4th capacitance, and 4 pins of pulse width modulating chip are through the 5th capacity earth, the pulsewidth modulation3 pins and 6 pins of chip are connected with current feedback circuit respectively；

The current feedback circuit includes the 6th capacitance being connected with 3 pins of pulse width modulating chip, the 6th capacity earth, pulsewidth3 pins of modulation chip are also connected with the 6th resistance, the 6th resistance through the 7th resistance eutral grounding, the 6th resistance also with first switch pipeSource electrode be connected, the grid of first switch pipe is connected through the 8th resistance with 6 pins of pulse width modulating chip, the leakage of first switch pipeThe first diode of pole is connected with 7 pins of pulse width modulating chip, first switch pipe drain electrode also with the primary side of high frequency transformerIt is connected.

4. a kind of inverse-excitation type switch power-supply as claimed in claim 3, it is characterised in that：The pulse width modulating chip usesUC3842 current source PWM chips.

5. a kind of inverse-excitation type switch power-supply as claimed in claim 4, it is characterised in that：The one of the primary side of the high frequency transformerEnd is connected with the first output end of bridge rectifier, and one end of the primary side of high frequency transformer is also successively through the 7th capacitance and secondDiode is connected with the other end of the primary side of high frequency transformer, and the 7th capacitance both ends are parallel with the 9th resistance, high frequency transformerFirst it is secondary while and second it is secondary while be separately connected output rectifier and filter.

6. a kind of inverse-excitation type switch power-supply as claimed in claim 5, it is characterised in that：The output rectifier and filter includesFirst current rectifying and wave filtering circuit and the second current rectifying and wave filtering circuit, the first current rectifying and wave filtering circuit and current rectifying and wave filtering circuit become with high frequency respectivelyThe first of depressor is secondary to be connected while with the second pair, and the first current rectifying and wave filtering circuit includes being connected with the first secondary side of high frequency transformerThe common end of third diode and the 8th capacitance, third diode and the 8th capacitance is successively through the first inductance and the 9th capacitance and heightFirst secondary side of frequency power transformer is connected, and the both ends of the 9th capacitance export first voltage, and the second current rectifying and wave filtering circuit includes and high frequencyThe secondary side of the second of transformer connected the 4th diode and the tenth capacitance, the common end of the 4th diode and the tenth capacitance passes through successivelySecond inductance and the 11st capacitance are connected with the first secondary side of high frequency transformer, and the both ends of the 11st capacitance export second voltage.