CN109980954A - Switching power circuit - Google Patents

Switching power circuit Download PDF

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Publication number
CN109980954A
CN109980954A CN201910297762.5A CN201910297762A CN109980954A CN 109980954 A CN109980954 A CN 109980954A CN 201910297762 A CN201910297762 A CN 201910297762A CN 109980954 A CN109980954 A CN 109980954A
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CN
China
Prior art keywords
resistance
circuit
capacitor
voltage
output
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Granted
Application number
CN201910297762.5A
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Chinese (zh)
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CN109980954B (en
Inventor
左洪波
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Suzhou Dune Electronics Technology Co Ltd
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Suzhou Dune Electronics Technology Co Ltd
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Priority to CN201910297762.5A priority Critical patent/CN109980954B/en
Publication of CN109980954A publication Critical patent/CN109980954A/en
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Classifications

    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02MAPPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/003Constructional details, e.g. physical layout, assembly, wiring or busbar connections
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K7/00Constructional details common to different types of electric apparatus
    • H05K7/20Modifications to facilitate cooling, ventilating, or heating
    • H05K7/2089Modifications to facilitate cooling, ventilating, or heating for power electronics, e.g. for inverters for controlling motor
    • H05K7/20909Forced ventilation, e.g. on heat dissipaters coupled to components
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K7/00Constructional details common to different types of electric apparatus
    • H05K7/20Modifications to facilitate cooling, ventilating, or heating
    • H05K7/2089Modifications to facilitate cooling, ventilating, or heating for power electronics, e.g. for inverters for controlling motor
    • H05K7/20945Thermal management, e.g. inverter temperature control

Abstract

A kind of switching power circuit includes: current rectifying and wave filtering circuit, switching circuit, control circuit, power supply circuit, main winding, transformer T1, output circuit, thermal-shutdown circuit, output overvoltage protection circuit; thermal-shutdown circuit includes: cooling drive control circuit comprising: thermistor RTH3, driving resistance R220, capacitor C220, voltage-stabilizing device SHR1, switching tube Q122, cooling power supply capacitor C221, capacitor C201;When power source temperature increases, thermistor RTH3 resistance value reduces, and driving resistance R220 voltage increases, when the conducting voltage for being greater than voltage-stabilizing device SHR1, the conducting of its C/A foot, the B/E foot of proximity switch pipe Q122 is connected, so that its C/E foot is connected, capacitor C201 charges by switching tube Q122 to capacitor C221, thermistor RTH3 resistance value is smaller, capacitor C221 voltage is higher, and cooling device output power is bigger, effectively cools down.

Description

Switching power circuit
Technical field
The present invention relates to a kind of power circuit, in particular to a kind of switching power circuit.
Background technique
Power supply provides electric energy electron equipment, while converting electrical energy into heat.When power source temperature is more than permission temperature, electricity The output in source will generate very big drift, and efficiency reduces, or even burns power supply.How to guarantee power supply under the conditions of suitable temperature Or work under temperature environment, it is to ensure that the key of power supply normal power supply.To extremely important to power supply progress heat dissipation design, scattered During thermal design, how as the case may be, suitable approach is used to transfer heat away to achieve the purpose that cooling, with The reliability for improving power work, prolongs its service life.If power source temperature is too low simultaneously and its working efficiency is influenced, is influenced Its working life influences its charge and discharge.
Summary of the invention
Based on this, it is necessary to provide a kind of switching power circuit that power supply can be adjusted cooling.
A kind of switching power circuit, comprising: current rectifying and wave filtering circuit, the switching circuit being connect with the current rectifying and wave filtering circuit, The control circuit that connect with the switching circuit, the power supply circuit connecting with the control circuit are connect with the switching circuit Primary side main winding, the transformer T1 that is arranged corresponding to the main winding, the defeated of the transformer T1 primary side is set Out circuit, be arranged in the transformer T1 primary side thermal-shutdown circuit, with the output circuit connecting detection output electricity The output overvoltage protection circuit that the control circuit carries out overvoltage protection is pressed and feeds back to, the switching circuit is arranged in the change The primary side of depressor T1, the control circuit include: main control unit, and the output circuit includes: to be arranged in the transformer T1 Primary side the first secondary windings, connect with first secondary windings output rectifier and filter, be arranged in output end Load circuit, the thermal-shutdown circuit include: access cooling device cooling power supply circuit, with the cooling power supply circuit It connects and output voltage is adjusted to adjust the cooling drive control circuit of cooling device output power, the drop according to power source temperature Warm power supply circuit includes: that the second subprime winding for the primary side that the transformer T1 is arranged in and the second subprime winding connect The cooling current rectifying and wave filtering circuit connect, the voltage regulation unit RG1 being connect with the cooling current rectifying and wave filtering circuit, the cooling rectifying and wave-filtering Circuit includes: the filter capacitor C200 for connecting and supplying electricity to cooling drive control circuit or cooling device with cooling device, described Cooling drive control circuit includes: corresponding to power supply to be arranged and detect power source temperature or temperature change and caused according to temperature change The thermistor RTH3 of change in resistance, the driving resistance R220 connecting with the thermistor RTH3, it is connected in parallel on driving resistance The capacitor C220 at the both ends R220, connect with the driving resistance R220 and according to driving resistance R220 both end voltage carry out conducting with No voltage-stabilizing device SHR1, with switching tube voltage-stabilizing device SHR1 connection and be connected according to voltage-stabilizing device SHR1 Q122, cooling device is connect and supplied electricity to the switching tube Q122 and electricity is caused according to the thermistor RTH3 change in resistance The cooling power supply capacitor C221 of buckling, it connect with cooling power supply capacitor C221 and switching tube Q122 and passes through switching tube Q122 and supply The capacitor C201 of cooling power supply capacitor C221 is supplied electricity to, the capacitor C201 is connect with voltage regulation unit RG1 output end, and the temperature-sensitive is electric Resistance RTH3 connects with driving resistance R220 and accesses the both ends the capacitor C201.
In a preferred embodiment, it is also connected with resistance R219 between the thermistor RTH3 and driving resistance R220, The voltage-stabilizing device SHR1 is zener diode or controllable source of stable pressure, and the switching tube Q122 is PNP type triode Q122, described Drive the reference end that voltage-stabilizing device SHR1 is accessed between resistance R220 and resistance R219, the capacitor C201, cooling power supply capacitor C221 is polar capacitor, and the cathode of the anode access capacitor C201 of the voltage-stabilizing device SHR1, the voltage-stabilizing device SHR1's is negative Pole accesses the base stage of triode Q122, the collector access cooling power supply capacitor C221 of the triode Q122 by resistance R223 Anode, its emitter access capacitor C201 anode, the cathode access capacitor C201's of the cooling power supply capacitor C221 is negative Pole is provided with resistance R222, the collector branch of the triode Q122 between the base stage and emitter of the triode Q122 One branch is linked between the driving resistance R220 and resistance R219 by diode D221, resistance R221, the resistance A branch is drawn between R219 and thermistor RTH3, and the output overvoltage protection circuit is accessed by voltage-stabiliser tube ZD153.
In a preferred embodiment, the output overvoltage protection circuit includes: the voltage-stabiliser tube connecting with the output circuit Or regulator tube group, connect with the voltage-stabiliser tube or regulator tube group diode D150, connect with diode D150 and receive over-voltage letter Number conducting photoelectrical coupler U3, the photoelectrical coupler U3 include: be arranged in transmitting terminal and with output overvoltage protection circuit Voltage-stabiliser tube or regulator tube group connection light emitting diode U3B, with the light emitting diode U3B be correspondingly arranged and receive this shine two The detection signal of pole pipe U3B will test signal and be transferred to the main control unit so that its photodiode for carrying out overvoltage protection U3A。
In a preferred embodiment, the output overvoltage protection circuit further include: connect with the photodiode U3A One-way SCR triode SCR1, the resistance R64 being connect with one-way SCR triode SCR1, the resistance in parallel with resistance R64 The control electrode of R65, one-way SCR triode SCR1 access the emitter of photodiode U3A and according to photodiode U3A It is connected and is connected, the other end of the resistance R64 being connected in parallel and resistance R65 access the power end of the main control unit, unidirectionally may be used The minus earth of control silicon triode SCR1, its anode are connect with resistance R64, and the emitter of photodiode U3A separately passes through resistance R66 ground connection, its collector access the power end of the main control unit by resistance R63, and the both ends resistance R66 are parallel with capacitor C60; The voltage-stabiliser tube or regulator tube group of the output overvoltage protection circuit include: zener diode ZD150, ZD151 of series connection, institute The cathode for stating zener diode ZD150 accesses the anode of the output circuit, and the cathode of the ZD151 accesses zener diode The anode of ZD150, the diode D150 anode accesses the anode of the ZD151, its cathode passes through described in resistance R150 access The anode of light emitting diode U3B, the cathode of the cathode access capacitor C201 of the light emitting diode U3B, the light emitting diode The both ends of U3B, which are provided with, is parallel with resistance R151 and capacitor C150;The cooling current rectifying and wave filtering circuit includes: and described second Grade winding connection diode D200, be arranged in the both ends diode D200 series connection capacitor C202 and resistance R207, and The resistance R208 of the diode D200 cathode connection, the resistance R209 for being connected in parallel on the both ends resistance R208, resistance R208 and resistance The anode of common end access filter capacitor C200, the cathode of filter capacitor C200 of R209 accesses the other end of second subprime winding And it is grounded, the input terminal for one end access voltage regulation unit RG1 that resistance R208 is connect with the anode of filter capacitor C200, the pressure stabilizing The ground terminal of unit R G1 is grounded, and the output head anode of the output circuit accesses the defeated of voltage regulation unit RG1 by diode D201 Enter end.
In a preferred embodiment, further includes: connect and detect output voltage or electric current with the output circuit to feed back Constant current protection is carried out to the main control unit or the output of constant voltage output detects feed circuit, and the output detects feed circuit packet It includes: detecting the output voltage of the output circuit or the detection unit U100 of electric current, connect with the output circuit and access institute State in detection unit U100 with detection unit U100 cooperate detection output circuit output electric current current sampling resistor, with it is described defeated The output end of circuit, which connects and accesses to cooperate in the detection unit U100 with detection unit U100, out carries out output voltage detection Voltage dividing resistance circuit, the photoelectrical coupler U2, the detection unit U100 that are connect with the amplifier U100 output end include: With the voltage dividing resistance circuit connection of the output detection feed circuit and by voltage dividing resistance circuit partial pressure compared with reference voltage Judgement and the amplifier U100A and output detection feed circuit that the control circuit is fed back to by photoelectrical coupler U2 Current sampling resistor connect and detect the output circuit output electric current or curent change amplifier U100B, amplifier Anti-phase input termination reference voltage, its normal phase input end of U100A access the partial pressure of voltage dividing resistance circuit connected to it, described Inverting input terminal of the output electric current of output circuit through current sampling resistor access amplifier U100B is simultaneously connect by capacitor C510 Enter its normal phase input end and be grounded, the photoelectrical coupler U2 includes: to be arranged in transmitting terminal and the amplifier U100A output end Or the output end of amplifier U100B connects and causes the light emitting diode U2B of curent change, setting to exist according to output voltage variation The detection signal that receiving end receives light emitting diode U2B will test signal and be transferred to the main control unit so that it is according to detection Signal adjusts output voltage with output constant current or the phototriode U2A of constant pressure.
In a preferred embodiment, the voltage dividing resistance circuit includes: to connect with the cathode output end of the output circuit Resistance R161, connect with resistance R161 resistance R162, connect with 162 other end of resistance and change dividing ratios to adjust Save the resistance R160 and capacitor of the variable resistance SVR1 of output voltage setting point, the series connection for being connected in parallel on the both ends resistance R161 C160, the resistance R163 for being connected in parallel on the both ends resistance R162, variable resistance SVR1 other end ground connection, the resistance R161 and resistance Output over-voltage protection output voltage is linked into amplifier U100A normal phase input end, the anti-phase input of amplifier U100A between R162 End is by the output end of reference voltage the chip SHR500, amplifier U100A of resistance R503 access offer reference voltage through two poles Pipe D500, resistance R520 access the anode of light emitting diode U2B, and the output end of amplifier U100A separately passes through capacitor C504, R504 Its inverting input terminal is accessed, reference voltage chip SHR500 plus earth, its cathode access amplifier U100A by resistance R503 Inverting input terminal, its reference end access its cathode, another branch of reference voltage chip SHR500 cathode is connect by capacitor C501 Ground, reverse phase of the branch through resistance R505 access amplifier U100B between the cathode and capacitor C501 of reference voltage chip SHR500 Input terminal;The current sampling resistor of resistance R510 of the output electric current of the output circuit through being connected in parallel and R511 composition accesses The inverting input terminal of amplifier U100B simultaneously accesses its normal phase input end by capacitor C510 and is grounded, and amplifier U100B's is defeated Outlet is linked into the anode of the light emitting diode U2B by resistance R520 through diode D510, its output end also passes through capacitor C512, resistance R512 feed back the inverting input terminal to amplifier U100B;The input terminal of voltage regulation unit RG1 is connect by resistance R500 Enter the power end to amplifier U100A, its output end is linked into the power end of amplifier U100A, amplifier by resistance R501 One branch of the power end of U100A accesses reference voltage by resistance R502 by capacitor C500 ground connection, its another branch The cathode of chip SHR500;The cathode of the light emitting diode U2B is grounded.
In a preferred embodiment, further includes: connect with the switching circuit and driving switch circuit work switch every From driving circuit, the main winding current detection circuit for being connect with the main winding and detecting main winding overcurrent, the power supply circuit Include: connect with the main control unit driving main control unit start-up circuit, the switch isolation driving circuit include: transformer T2, the T2 armature winding that transformer T2 primary side is set, the first secondary windings of T2 and T2 that transformer T2 primary side is set Armature winding connects and accesses the driving end of the main control unit to amplify the amplifying circuit of driving signal, be arranged in transformer T2 The T2 second subprime winding of primary side, the switching circuit include: the switching tube Q1 being connect with first secondary windings of T2, with The switching tube Q2 of the T2 second subprime winding connection, main winding is arranged between the switching tube Q1 and switching tube Q2, described Start-up circuit includes: to access the first start-up resistor of the current rectifying and wave filtering circuit or resistance group, connect with the resistance or resistance group Switching tube Q50, the second start-up resistor for being connect with the switching tube Q50 other end or resistance group, connect with the switching tube Q50 It connects and the main control unit is accessed in the one end capacitor C37, the switching tube Q50 charged according to the conducting of switching tube Q50 Power end;The main winding current detection circuit include: by the electric current of main winding be converted into voltage detecting electric current inductive reactance, The resistance R60 of the test side of the main control unit is connect and accessed with electric current inductive reactance one end and connect with resistance R60 Capacitor C53.
In a preferred embodiment, the switching tube Q50 is according to the voltage turn-on between grid and source electrode or to turn off it The N-channel MOS pipe for draining and connecting between source electrode, first start-up resistor or resistance group include: the resistance of series connection R20, R21, R22, R20 are accessed in the current rectifying and wave filtering circuit, and the second start-up resistor or resistance group include the pressure stabilizing being connected in series Diode ZD20, resistance R24, resistance R25, the cathode and resistance R20 of zener diode ZD20 access the rectification after converging and filter In wave circuit, resistance R25 accesses the grid of metal-oxide-semiconductor Q50, and resistance R22 accesses the drain electrode of metal-oxide-semiconductor Q50, and capacitor C37 is polarity electricity Hold, the anode of source electrode access capacitor C37, the cathode of capacitor C37 of metal-oxide-semiconductor Q50 is grounded, and the grid of metal-oxide-semiconductor Q50 separately passes through pressure stabilizing It is provided with capacitor C33 between pipe ZD50 ground connection, its grid and source electrode, the both ends capacitor C33 are parallel with resistance R26, metal-oxide-semiconductor Q50's Source electrode separately separates the power end for accessing the main control unit and is grounded by capacitor C50;In the switch isolation driving circuit Amplifying circuit includes: described in the base stage access of NPN triode Q51, PNP triode Q52, the triode Q51, triode Q52 The driving end of main control unit, the collector of the triode Q51 access the power end of the main control unit, the triode Q51 Emitter connect with the emitter of triode Q52, the emitter of the triode Q51 or the emitter of triode Q52 pass through Capacitor C19 access T2 armature winding one end, triode Q52 collector access the T2 armature winding other end, triode Q51 collection Electrode also accesses the T2 armature winding other end by capacitor C20, and described switching tube Q1, Q2 are the enhanced metal-oxide-semiconductor of N-channel, described The the first secondary windings one end T2 accesses the grid of metal-oxide-semiconductor Q1 by resistance R11, its other end accesses the source electrode of metal-oxide-semiconductor Q1, MOS The drain electrode of pipe Q1 accesses in the current rectifying and wave filtering circuit, and the both ends resistance R11 are parallel with diode D12, the resistance of series connection The cathode of R10, diode D12 access the first secondary windings of T2 one end, are provided with resistance between the grid and source electrode of metal-oxide-semiconductor Q1 R12 is provided with capacitor C13, C14 of series connection, the source electrode of the metal-oxide-semiconductor Q1 between the drain electrode and source electrode of the metal-oxide-semiconductor Q1 Also access one end of main winding, the other end of main winding accesses the drain electrode of metal-oxide-semiconductor Q1 by diode D10, main winding both ends it Between be additionally provided with capacitor C26, the grid of metal-oxide-semiconductor Q2 accesses one end of T2 second subprime winding by resistance R15, diode D15, The other end of T2 second subprime winding by diode D11 access main winding one end, resistance R15, diode D15 both ends simultaneously It is associated with resistance R14, capacitor C16, C15 of series connection, electric current inductive reactance packet are provided between the drain electrode and source electrode of metal-oxide-semiconductor Q2 Include: the resistance R18, the resistance R19 that are connected in parallel, the one end resistance R18 by metal-oxide-semiconductor Q2 access main winding, its access metal-oxide-semiconductor Q2 Source electrode, other end ground connection.
In a preferred embodiment, further includes: be arranged in the current rectifying and wave filtering circuit front end EMC circuit, with it is described whole The input voltage detection circuit of input voltage, the remote control communicated with the main control unit are opened after stream filter circuit connecting detection rectification Powered-down road, the power supply circuit further include: the soft starting circuit that connect with the start-up circuit is connect simultaneously with the start-up circuit The transformer type power supply circuit of the main control unit is accessed, the soft starting circuit includes: point connecting with the start-up circuit Piezoresistance, the charging capacitor connecting with the divider resistance are connect and according to the charging situation of the charging capacitor with the divider resistance And be connected switching tube Q70, with the switching tube Q70 connection and the access main control unit be connected according to switching tube Q70 prolong The resistance R73 of Shi Duan, charging capacitor one end is connect with divider resistance, the other end is connect with the feedback end of the main control unit, institute The other end ground connection of switching tube Q70 is stated, the delay end of the main control unit separately passes through resistance R52 and is grounded;The transformer type supplies Circuit include: be arranged in transformer T1 primary side primary auxiliary winding, be arranged on primary auxiliary winding chip power supply it is whole Stream filter circuit connect with the chip power-supply rectifying filter circuit and supplies electricity to the reduction voltage circuit of the main control unit, described Chip power-supply rectifying filter circuit includes: the diode D30 that primary auxiliary winding one end is arranged in, the electricity connecting with diode D30 The capacitor C36 for hindering R31, connecting the other end of resistance R31 and the other end of primary auxiliary winding, the reduction voltage circuit include: and institute The voltage-stabiliser tube ZD30 of the other end of the switching tube Q30 of resistance R31 connection, the connection switch pipe Q30 other end and primary auxiliary winding is stated, The EMC circuit includes: filter capacitor and common mode inductance, and the filter capacitor in the EMC circuit includes: to be arranged in input line The X capacitor at both ends, the Y capacitance being arranged between input line and ground wire, the input voltage detection circuit include: that access is described whole The divider resistance of the input voltage after filter circuit rectifies is flowed, the partial pressure through divider resistance connects in the input voltage detection circuit Enter the low pressure detection input of the main control unit;The remote control switching circuit includes: that remote control trigger device and the remote control are touched The photoelectrical coupler U4, the photoelectrical coupler U4 of hair device connection include: that setting connects in transmitting terminal and with remote control trigger device It connects and because the light emitting diode U4B of remote control trigger conducting, setting receive light emitting diode U4B signal in receiving end and are transferred to institute State the phototriode U4A that main control unit is controlled.
In a preferred embodiment, the divider resistance in the soft starting circuit include: sequentially connected resistance R72, R71, the one end resistance R72 access cathode of capacitor C37, the end are simultaneously grounded, the charging capacitor in the resistance R71 other end and its circuit It connects, the charging capacitor in the soft starting circuit includes: the capacitor C70 and C71 being connected in parallel, shunt capacitance C70's and C71 The other end accesses the feedback end of the main control unit, and the both ends of sequentially connected resistance R72 and R71 are provided with the electricity of series connection R70 and diode D70 is hindered, cathode, its other end for one end access capacitor C37 that resistance R70 is connect with resistance R72 access two poles The anode of pipe D70, the cathode of diode D70 are connected to capacitor C70, and the switching tube Q70 is N-channel MOS pipe, the access of its grid Between resistance R72 and R71, its source electrode access capacitor C37 cathode and ground connection;The switching tube Q30 is NPN triode, described The both ends diode D30 are provided with series resistance R30 and capacitor C35, and the both ends resistance R31 are parallel with resistance R34, the one end resistance R31 It is connect with the cathode of diode D30, the collector of its other end access triode Q30, capacitor C36 is polar capacitor, resistance R31 The other end branch access capacitor C36 anode, be provided with resistance R32, voltage-stabiliser tube between the collector and base stage of triode Q30 ZD30 is zener diode, and cathode, its emitter of the base stage access zener diode ZD30 of triode Q30 passes through diode D31, resistance R33 access the power end of the main control unit, between the base stage of the triode Q30 and the anode of diode D31 Draw the low pressure detection input that a branch accesses the main control unit by resistance R74, the cathode of capacitor C36, two pole of pressure stabilizing The plus earth of pipe ZD30;The EMC circuit further include: the varistor ZNR1 between fiery zero curve is set, is arranged in fire zero Resistance R2, R1 of series connection between line, the one end resistance R1 is connect with resistance R2, the other end accesses firewire, and resistance R2 is another It terminates into zero curve, the Y capacitance includes: the capacitor accessed between the capacitor C23 between firewire and ground wire, access firewire and ground wire Capacitor C24, access zero curve between C3, access zero curve and ground wire and the capacitor C4 between ground wire, the X capacitor include: access Capacitor C1, C2 between firewire or zero curve, the one end capacitor C3 is connect with capacitor C4, its other end accesses firewire, and capacitor C4 is another It terminates into zero curve, the common mode inductance includes: common mode inductance LF1, and the both ends of a coil of the common mode inductance LF1 are respectively connected to Resistance R1, the capacitor C3 other end simultaneously access firewire, the both ends of another coil be respectively connected to resistance R2, capacitor C4 the other end simultaneously Zero curve is accessed, the divider resistance of the input voltage detection circuit includes: sequentially connected resistance R45, R46, R47, R53, institute State the Input voltage terminal after the current rectifying and wave filtering circuit rectification is accessed in the one end resistance R45, its other end is connect with resistance R46, electricity The low pressure test side of the main control unit, resistance R53 other end ground connection are accessed between resistance R53 and R47;Phototriode U4A's Collector accesses the low pressure test side of the main control unit, its emitter ground connection, the ground terminal ground connection of main control unit;The remote control Switching circuit further include: with the concatenated resistance R600 of light emitting diode U4B, be connected in parallel on the both ends light emitting diode U4B it is in parallel even The anode of remote control trigger device CN600, its other end access hair are accessed in the resistance R601 and capacitor C601 connect, the one end resistance R600 The anode of optical diode U4B, the cathode of the cathode access remote control trigger device CN600 of light emitting diode U4B.
Above-mentioned switching power circuit, after the confession of main control unit electrically activates, driving switch circuit carries out power conversion, cooling After the ac voltage rectifier filtering that the cooling current rectifying and wave filtering circuit of power supply circuit arrives the second subprime winding coupled of transformer T1 Direct current is exported, the voltage of filter capacitor C200 is down to setting voltage or cooling drive control circuit using voltage regulation unit RG1 Cooling driving is carried out with fan;When power source temperature increases, thermistor RTH3 resistance value reduces, and drives resistance R220 both end voltage It increases, when its voltage is greater than the conducting voltage of voltage-stabilizing device SHR1, the C/A foot conducting of voltage-stabilizing device SHR1, driving switch pipe Q122 conducting, i.e. the B/E foot conducting of the C/A foot conducting proximity switch pipe Q122 of voltage-stabilizing device SHR1, thus triode Q122 The conducting of C/E foot, capacitor C201 charge by switching tube Q122 to capacitor C221, final voltage and thermistor RTH3 resistance value phase It closes, thermistor RTH3 resistance value is smaller, and capacitor C221 voltage is higher, and capacitor C221 powers to fan, and output power is bigger, cooling The output power of device is bigger, and revolving speed is also bigger, i.e., power source temperature is higher, and driving fan revolving speed is faster;Work as power source temperature When decline, the course of work adjusts its output power conversely, to adjust control cooling device according to the power source temperature detected, So that it is carried out flexible modulation according to the heat condition of power supply, effectively cool down to power supply, while electric energy is efficiently used, It is energy saving.
Detailed description of the invention
Fig. 1 is the partial schematic diagram of the primary side of the transformer T1 of the switching power circuit of one embodiment of the invention;
Fig. 2 is the partial schematic diagram of the primary side of the transformer T1 of the switching power circuit of one embodiment of the invention.
Specific embodiment
As shown in Figure 1 to Figure 2, the switching power circuit of one embodiment of the invention, comprising: current rectifying and wave filtering circuit B and rectification The switching circuit J of filter circuit B connection, the control circuit being connect with switching circuit J, the power supply circuit connected to the control circuit, To the main winding 4-6 of the primary side of switching circuit J connection, the transformer T1 that is arranged corresponding with main winding 4-6, setting in transformer The output circuit K of T1 primary side, be arranged in transformer T1 primary side thermal-shutdown circuit, with output circuit K connecting detection Output voltage simultaneously feeds back to the output overvoltage protection circuit N that control circuit carries out overvoltage protection.
The primary side of transformer T1 is arranged in switching circuit J.Control circuit includes: main control unit U1.Main control unit U1 control The information of system acquisition interlock circuit or partial function circuit, and controlled according to collected information.Output circuit K includes: The first secondary windings 9.10-7.8 that the primary side of transformer T1 is set, the output being connect with the first secondary windings 9.10-7.8 Current rectifying and wave filtering circuit, the load circuit that output end is set.
Thermal-shutdown circuit include: access cooling device cooling power supply circuit L, with cooling power supply circuit L connect simultaneously root Output voltage is adjusted according to power source temperature to adjust the cooling drive control circuit M of cooling device output power.
The power supply circuit L that cools down includes: the second subprime winding 11-12 for the primary side that transformer T1 is arranged in and second The cooling current rectifying and wave filtering circuit of grade winding 11-12 connection, the voltage regulation unit RG1 being connect with cooling current rectifying and wave filtering circuit.
The cooling current rectifying and wave filtering circuit of the present embodiment includes: to connect and supply electricity to cooling drive control circuit with cooling device Or the filter capacitor C200 of cooling device.
Further, the cooling current rectifying and wave filtering circuit of the present embodiment further include: two poles being connect with second subprime winding 11-12 Pipe D200, the both ends diode D200 are set and are connected in series capacitor C202 and resistance R207, connect with diode D200 cathode The resistance R208 that connects, the resistance R209 for being connected in parallel on the both ends resistance R208.The common end of resistance R208 and resistance R209, which is accessed, to be filtered The anode of capacitor C200, the other end i.e. 12 ends of the cathode access second subprime winding of filter capacitor C200 are simultaneously grounded.Resistance The input terminal for one end access voltage regulation unit RG1 that R208 is connect with the anode of filter capacitor C200.The ground terminal of voltage regulation unit RG1 Ground connection.The output head anode of output circuit K accesses the input terminal of voltage regulation unit RG1 by diode D201.
Preferably, circuit of three-terminal voltage-stabilizing integrated 7812 can be selected in the voltage regulation unit RG1 of the present embodiment.
The cooling drive control circuit M of the present embodiment includes: is arranged to detect power source temperature or temperature become corresponding to power supply Change and the thermistor RTH3 of change in resistance caused according to temperature change, the driving resistance R220 that is connect with thermistor RTH3, It is connected in parallel on the capacitor C220 at the driving both ends resistance R220, connect with driving resistance R220 and according to driving resistance R220 both end voltage Voltage-stabilizing device SHR1 whether conducting, it is connected with voltage-stabilizing device SHR1 connection and according to voltage-stabilizing device SHR1 Switching tube Q122, cooling device is connect and supplied electricity to switching tube Q122 and voltage is caused according to thermistor RTH3 change in resistance The cooling power supply capacitor C221 of variation, it connect with cooling power supply capacitor C221 and switching tube Q122 and passes through switching tube Q122 and power To the capacitor C201 of cooling power supply capacitor C221.Capacitor C201 is connect with voltage regulation unit RG1 output end.Thermistor RTH3 and drive Dynamic resistance R220 connects and accesses the both ends capacitor C201.
Further, resistance R219 is also connected between the thermistor RTH3 of the present embodiment and driving resistance R220.Pressure stabilizing Device SHR1 is zener diode or controllable source of stable pressure.
Further, the switching tube Q122 of the present embodiment is PNP type triode Q122.Drive resistance R220 and resistance R219 it Between access voltage-stabilizing device SHR1 reference end.The voltage-stabilizing device of model LA431 can be selected in the voltage-stabilizing device SHR1 of the present embodiment, Also voltage-stabiliser tube can be selected.Capacitor C201, cooling power supply capacitor C221 are polar capacitor.The anode access capacitor of voltage-stabilizing device SHR1 The cathode of C201.The cathode of voltage-stabilizing device SHR1 accesses the base stage of triode Q122 by resistance R223.The collection of triode Q122 Anode, its emitter of electrode access cooling power supply capacitor C221 accesses the anode of capacitor C201.Cool down power supply capacitor C221's The cathode of cathode access capacitor C201.Resistance R222 is provided between the base stage and emitter of triode Q122.Triode Q122 One branch of collector branch by diode D221, resistance R221 be linked into driving resistance R220 and resistance R219 between.Electricity A branch is drawn between resistance R219 and thermistor RTH3, and output overvoltage protection circuit is accessed by voltage-stabiliser tube ZD153.
Output overvoltage protection circuit N include: with the output circuit K voltage-stabiliser tube connecting or regulator tube group, with the voltage-stabiliser tube or The diode D150 of regulator tube group connection, the photoelectrical coupler U3 for being connect with diode D150 and receiving over-voltage signal conduction.Light Electric coupler U3 includes: transmitting terminal is arranged in and connect with the voltage-stabiliser tube of output overvoltage protection circuit or regulator tube group luminous two Pole pipe U3B, the detection signal for being correspondingly arranged with light emitting diode U3B and receiving light emitting diode U3B will test signal transmission To main control unit U1 so that its photodiode U3A for carrying out overvoltage protection.
Output overvoltage protection circuit further include: the one-way SCR triode SCR1 and list being connect with photodiode U3A Resistance R64, the resistance R65 in parallel with resistance R64 to triode thyrister SCR1 connection, one-way SCR triode SCR1's The emitter of control electrode access photodiode U3A is simultaneously connected according to photodiode U3A and is connected.The resistance being connected in parallel The power end VCC of the other end access main control unit U1 of R64 and resistance R65.The minus earth of one-way SCR triode SCR1, Its anode is connect with resistance R64.The emitter of photodiode U3A separately passes through resistance R66 ground connection, its collector passes through resistance The power end VCC of R63 access main control unit U1.The both ends resistance R66 are parallel with capacitor C60.
The voltage-stabiliser tube or regulator tube group of output overvoltage protection circuit include: series connection zener diode ZD150, ZD151.The anode of the cathode access output circuit of zener diode ZD150.The cathode of ZD151 accesses zener diode ZD150 Anode.Diode D150 anode accesses the anode of ZD151, its cathode and is accessing light emitting diode U3B just by resistance R150 Pole.The cathode of the cathode access capacitor C201 of light emitting diode U3B.The both ends of light emitting diode U3B, which are provided with, is parallel with resistance R151 and capacitor C150.
In the present embodiment, cooling device is illustrated using fan, other cooling devices can also be used certainly.The present embodiment Main control unit U1 by power supply circuit for after electrically activating, driving power switch carries out power conversion, and diode D200 is by transformation After the ac voltage rectifier that the second subprime winding 11-12 of device T1 is coupled to, then through resistance R208, R209, capacitor C200 filtering Become direct current, supplies cooling drive control circuit M and wind after the voltage of capacitor C200 is down to 12V using voltage regulation unit RG1 Fan.
When power source temperature increases, thermistor RTH3 resistance value reduces, and resistance R220 both end voltage increases, when its voltage is big When 2.5V, the C/A foot of voltage-stabilizing device SHR1 is connected, the B/E foot conducting of triode Q122, thus the C/E foot of triode Q122 Conducting, capacitor C201 charge by triode Q122 to capacitor C221.Its final voltage is related to thermistor RTH3 resistance value, heat Quick resistance RTH3 resistance value is smaller, and capacitor C221 voltage is higher, and setting is up to 12V in the present embodiment.Capacitor C221 is supplied to fan Electricity.Power source temperature is higher, and driving fan revolving speed is faster.When power source temperature decline, the course of work is on the contrary.
When the output voltage of output circuit is greater than the pressure stabilizing value of voltage-stabiliser tube ZD150+ZD151, voltage-stabiliser tube ZD150, ZD151 Conducting, the light emitting diode U3B conducting of the transmitting terminal of photoelectrical coupler, is arranged in the light of the primary side of output overvoltage protection circuit The photodiode U3A of the receiving end of electric coupler detects the light emitting diode U3B conducting of transmitting terminal, then triggers OVP and protects It protects (output voltage overvoltage protection), power supply is closed in control.
Output circuit K includes: the first secondary windings 9.10-7.8 and first grade for the primary side that transformer T1 is arranged in The output rectifier and filter of winding 9.10-7.8 connection, the load circuit that output end is set.
Q101, Q102, D61, D62, D63, L100, C105, C106, C107, C108 in output rectifier and filter will It is DC output voltage that the PWM voltage that first secondary windings 9.10-7.8 of the primary side of T1 is coupled to, which carries out rectifying and wave-filtering, defeated Voltage is directly proportional to the voltage value of PWM voltage and duty ratio out.
The current rectifying and wave filtering circuit B of the present embodiment includes: input rectification circuit, input filter circuit.Input rectification circuit packet It includes: rectifier bridge BD1.Input filter circuit includes: filter capacitor C5, C6.
Filter capacitor C5, C6 are polar capacitor.Cathode output end after rectified bridge BD1 rectification is after thermistor RTH1 It is linked into the anode of filter capacitor C5, zero curve input terminal enters the cathode of filter capacitor C5 after common mode inductance LF1, switch SW1. The both ends filter capacitor C5 are parallel with the resistance R6 and R5 of series connection, and both ends are also parallel with varistor ZNR5.
Cathode output end after rectified bridge BD1 rectification is linked into the cathode of filter capacitor C6 and is connect after resistance RTH2 Ground, the cathode of the anode access filter capacitor C5 of filter capacitor C6.The both ends filter capacitor C6 are parallel with the resistance R7 of series connection With R8, both ends are also parallel with varistor ZNR6.It is set between cathode output end and ground wire input terminal after rectifier bridge BD1 rectification It is equipped with capacitor C30.
The current rectifying and wave filtering circuit B of the present embodiment further include: be arranged between the positive and negative anodes of rectified bridge BD1 rectification output Capacitance group.The capacitance group includes: capacitor C9, C10, C11, the C12 being connected in parallel.The one of C9, C10, C11, the C12 being connected in parallel End ground connection, the other end access switching circuit.
The current rectifying and wave filtering circuit B of the present embodiment filters AC-input voltage after rectifier bridge BD1 rectification, then by C5, C6 Wave is transformed to DC voltage.In power supply booting, varistor RTH1, varistor RTH2 can inhibit inrush current.
Further, the switching power circuit of the present embodiment further include: output voltage or electricity are connect and detected with output circuit K Stream carries out constant current protection or the output of constant voltage output detection feed circuit P, Q to feed back to main control unit U1.It is defeated in the present embodiment The portion P detected in feed circuit out is mainly output electric current measure and feedback, and the part Q is mainly output voltage detection and anti- Feedback.
Further, the output detection feed circuit of the present embodiment includes: the output voltage or electric current for detecting output circuit Detection unit U100, it is connect with output circuit and accesses to cooperate in detection unit U100 with detection unit U100 and detect output circuit Export electric current current sampling resistor, connect with the output end of output circuit and access in detection unit U100 with detection unit U100 cooperation carries out the voltage dividing resistance circuit of output voltage detection, the photoelectrical coupler U2 connecting with amplifier U100 output end.
Detection unit U100 includes: connect with the voltage dividing resistance circuit of output detection feed circuit and the divider resistance is electric Road partial pressure feeds back to amplifier U100A and the output of control circuit with reference voltage multilevel iudge and by photoelectrical coupler U2 The current sampling resistor of detection feed circuit connects and detects the output electric current of output circuit or the amplifier of curent change U100B.Anti-phase input termination reference voltage, its normal phase input end of amplifier U100A accesses divider resistance electricity connected to it The partial pressure on road.
Inverting input terminal of the output electric current of output circuit through current sampling resistor access amplifier U100B simultaneously passes through electricity Hold C510 to access its normal phase input end and be grounded.Photoelectrical coupler U2 includes: to be arranged in transmitting terminal and amplifier U100A output end Or amplifier U100B output end connection and according to amplifier output voltage variation cause curent change light emitting diode U2B, It is correspondingly arranged with light emitting diode U2B and the detection signal for receiving light emitting diode U2B will test signal and be transferred to master control list First U1 is so that it adjusts output voltage according to detection signal with output constant current or the phototriode U2A of constant pressure.
Further, the voltage dividing resistance circuit of the present embodiment includes: the resistance connecting with the cathode output end of output circuit R161, the resistance R162 being connect with resistance R161, it is connect with 162 other end of resistance and changes dividing ratios to adjust output voltage The variable resistance SVR1 of set-point, be connected in parallel on the both ends resistance R161 series connection resistance R160 and capacitor C160, be connected in parallel on The resistance R163 at the both ends resistance R162.
Variable resistance SVR1 other end ground connection, the partial pressure value of the resistance adjustment dividing point of adjustment variable resistance SVR1, with suitable Answer the demand of different loads or different product, different scenes.
Output over-voltage protection output voltage is linked into amplifier U100A between the resistance R161 and resistance R162 of the present embodiment Normal phase input end.The inverting input terminal of amplifier U100A provides the reference voltage chip of reference voltage by resistance R503 access SHR500.Anode of the output end of amplifier U100A through diode D500, resistance R520 access light emitting diode U2B.Amplifier The output end of U100A separately passes through capacitor C504, R504 and accesses its inverting input terminal, reference voltage chip SHR500 plus earth, Its cathode accesses the inverting input terminal of amplifier U100A by resistance R503, its cathode is accessed in its reference end.
Another branch of reference voltage chip SHR500 cathode is grounded by capacitor C501, the yin of reference voltage chip SHR500 Inverting input terminal of the branch through resistance R505 access amplifier U100B between pole and capacitor C501.The output electric current of output circuit The inverting input terminal for the current sampling resistor access amplifier U100B that resistance R510 and R511 through being connected in parallel is formed simultaneously is led to Capacitor C510 is crossed to access its normal phase input end and be grounded.Current sampling resistor is linked at the J109 of output circuit.Amplifier The output end of U100B is linked into the anode of light emitting diode U2B by resistance R520 through diode D510, its output end also passes through Capacitor C512, resistance R512 feed back the inverting input terminal to amplifier U100B.The input terminal of voltage regulation unit RG1 passes through resistance R500 is linked into the power end of amplifier U100A, its output end is linked into the power end of amplifier U100A by resistance R501. One branch of the power end of amplifier U100A accesses base by resistance R502 by capacitor C500 ground connection, its another branch The cathode of quasi- voltage chips SHR500.The cathode of light emitting diode U2B is grounded.
It will be with output electricity with the current potential of the tie point of the resistance R510 and R511 that are connected in parallel at the J109 of output circuit K Rheology is big and reduces, so that the 6 foot current potentials of detection unit U100 reduce, i.e. the current potential of the normal phase input end of amplifier U100B Reduce, when it is less than 0V, the output end of 7 feet of detection unit U100, i.e. amplifier U100B exports high level, to make The electric current of the light emitting diode U2B of the transmitting terminal of photoelectrical coupler U2 increases, and transmits signals to the phototriode of receiving end Pipe U2A, so that the output curent change for the output circuit that will test is transferred to main control unit U1, main control unit U1 drives PWM Duty ratio decline, output electric current reduce, and by this negative-feedback circuit, exporting electric current will stablize in OCP (output overcurrent protection) Set-point, this protected mode are constant current protection, are conducive to power supply output with biggish perception or capacitive load, solve practical application In recurrent power supply hiccup protections problem.
The output voltage of output circuit K is after resistance R160~R163 and variable resistance SVR1 partial pressure, point of dividing point Pressure is input to the normal phase input end of amplifier U100A, the partial pressure and reference voltage chip that detection unit U100 will test The reference voltage such as 2.5V that SHR500 is generated is compared, when partial pressure is greater than 2.5V, detection unit U1001 foot output voltage liter The output end voltage of height, i.e. amplifier U100A increases, thus make the light emitting diode U2B of the transmitting terminal of photoelectrical coupler U2 Electric current increases, and transmits signals to the phototriode U2A of receiving end, thus the output electric current for the output circuit that will test Variation is transferred to main control unit U1, makes main control unit U1 driving PWM duty cycle decline, output voltage reduces, by this negative-feedback Circuit, output voltage will be stablized in output voltage setting point.Variable resistance SVR1 can change dividing ratios, to change defeated Voltage set point out.
The detection unit U100 of the present embodiment preferably selects the chip of model LM258 to be realized, does not limit to certainly In the model chip, as long as realizing the function of this detection feed circuit.
The main control unit U1 of the present embodiment is preferably the control chip of model NCP1252.It is certainly not limited to this chip, only It can control the function of realizing switching circuit of the invention, realize detection of the invention, control function.
Further, the switching power circuit of the present embodiment further include: connect with switching circuit J and driving switch circuit works Switch isolation driving circuit H, the main winding current detection circuit I that is connect with main winding 4-6 and detect main winding overcurrent.
The switch isolation driving circuit H of the present embodiment includes: transformer T2, the T2 primary that transformer T2 primary side is arranged in Winding 10-1, it the first secondary windings of T2 6-3 that transformer T2 primary side is set, is connect with T2 armature winding and accesses master control list T2 second subprime winding of the driving end DRV of first U1 to amplify the amplifying circuit of driving signal, transformer T2 primary side is arranged in.
The switching circuit J of the present embodiment include: the switching tube Q1 being connect with the first secondary windings of T2, with T2 second subprime around The switching tube Q2 of group connection.Main winding 4-6 is arranged between switching tube Q1 and switching tube Q2.
Further, the amplifying circuit in the switch isolation driving circuit of the present embodiment includes: NPN triode Q51, PNP tri- Pole pipe Q52.The driving end DRV of the base stage access main control unit U1 of triode Q51, triode Q52, i.e. 6 feet of main control unit U1. The power end VCC of the collector access main control unit U1 of triode Q51.The transmitting of the emitter and triode Q52 of triode Q51 Pole connection, the emitter of triode Q51 or the emitter of triode Q52, the i.e. emitter of triode Q51 are with triode Q52's The common end of emitter accesses one end 10 of T2 armature winding 10-11 by capacitor C19, the collector of triode Q52 accesses T2 The armature winding other end 11.The collector of triode Q51 also accesses the T2 armature winding other end 11 by capacitor C20.
Further, switching tube Q1, Q2 of the present embodiment are the enhanced metal-oxide-semiconductor of N-channel.The first secondary windings of T2 one end passes through Resistance R11 accesses the source electrode of the grid of metal-oxide-semiconductor Q1, its other end access metal-oxide-semiconductor Q1.The drain electrode of metal-oxide-semiconductor Q1 accesses rectifying and wave-filtering In circuit B, the both ends resistance R11 are parallel with the diode D12 of series connection, resistance R10.The cathode access T2 the of diode D12 One end 6 of one secondary windings 6-3.Resistance R12 is provided between the grid and source electrode of metal-oxide-semiconductor Q1.The drain electrode of metal-oxide-semiconductor Q1 and source electrode Between be provided with capacitor C13, C14 of series connection.The source electrode of metal-oxide-semiconductor Q1 also accesses one end 4 of main winding 4-6.Main winding 4-6 The other end 6 by diode D10 access metal-oxide-semiconductor Q1 drain electrode.Capacitor C26 is additionally provided between the both ends of main winding 4-6. The grid of metal-oxide-semiconductor Q2 accesses one end 8 of T2 second subprime winding 8-5, T2 second subprime winding by resistance R15, diode D15 The other end 5 of 8-5 accesses one end 4 of main winding 4-6 by diode D11.Resistance R15, diode D15 both ends be parallel with electricity Hinder R14.Capacitor C16, C15 of series connection are provided between the drain electrode and source electrode of metal-oxide-semiconductor Q2.Electric current inductive reactance includes: simultaneously Join resistance R18, the resistance R19 of connection.Main winding 4-6, its source for accessing metal-oxide-semiconductor Q2 are accessed by metal-oxide-semiconductor Q2 in the one end resistance R18 Pole, other end ground connection.
Metal-oxide-semiconductor Q1, Q2 are driven or are turned off by main control unit U1 simultaneously, and exchange is generated on the main winding 4-6 of transformer T1 PWM voltage, allows to transmit energy to other windings of T1, and diode D10, D11 are transformer T1 magnetizing inductance resetting current Access.
Further, the main winding current detection circuit I of the present embodiment includes: to convert voltage detecting for the electric current of main winding Electric current inductive reactance, the test side CS for being connect with electric current inductive reactance one end and accessing main control unit U1 resistance R60 and with The capacitor C53 of resistance R60 connection.The test side CS of main control unit U1, other end ground connection are accessed in the one end capacitor C53.
Ground connection one end of capacitor C53 or an extremely another second subprime winding 11- by capacitor C3 access cooling power supply circuit L 12 12 ends.
Main winding current detection circuit I detects the electric current of main winding 4-6, and by resistance R18, R19 by transformer T1's The current value of main winding 4-6 is converted into voltage value, and the test side of main control unit U1 is inputted after resistance R60, capacitor C53 filtering CS, i.e. 3 feet.If the voltage that main control unit U1 detects its test side CS is greater than 1V, closing driving is controlled, to prevent main winding The electric current of 4-6 is excessive, achievees the purpose that carry out overpower protection to primary side.
Further, the power supply circuit of the present embodiment includes: the starting that main control unit U1 is connect and driven with main control unit U1 Circuit D.
The start-up circuit D of the present embodiment include: access current rectifying and wave filtering circuit B the first start-up resistor or resistance group, with the One start-up resistor or switching tube Q50, the second start-up resistor for being connect with the switching tube Q50 other end or the resistance of the connection of resistance group Group, the capacitor C37 for connecting with switching tube Q50 and being charged according to the conducting of switching tube Q50.The one end switching tube Q50 access master Control the power end VCC of unit U1.
Switching tube Q50 is to be connect between its drain electrode and source electrode according to voltage turn-on between grid and source electrode or turn off N-channel MOS pipe.The source electrode of metal-oxide-semiconductor Q50 separately separates the power end VCC of access main control unit U1 and is grounded by capacitor C50.
First start-up resistor or resistance group include: resistance R20, R21, R22 of series connection.R20 accesses rectifying and wave-filtering electricity In the B of road.Preferably, R20 access rectified filter circuit rectification circuit BD1 rectification after, the output after thermistor RTH1 End.Second start-up resistor or resistance group include: the zener diode ZD20, resistance R24, resistance R25 of series connection.Two pole of pressure stabilizing The cathode of pipe ZD20 and resistance R20 are accessed in current rectifying and wave filtering circuit B after converging, and after accessing rectified circuit BD1 rectification output, Output end after thermistor RTH1.
The grid of resistance R25 access metal-oxide-semiconductor Q50.The drain electrode of resistance R22 access metal-oxide-semiconductor Q50.Capacitor C37 is polarity electricity Hold.The anode of the source electrode access capacitor C37 of metal-oxide-semiconductor Q50.The cathode of capacitor C37 is grounded.The grid of metal-oxide-semiconductor Q50 separately passes through pressure stabilizing Capacitor C33 is provided between pipe ZD50 ground connection, its grid and source electrode.The both ends capacitor C33 are parallel with resistance R26.
Access alternating current, L/N is when just powering on for input, and capacitor C37 voltage is 0V, at this time the grid G Yu source S of metal-oxide-semiconductor Q50 it Between voltage be 15V, be connected between the drain D and source S of metal-oxide-semiconductor Q50.
The electric current exported after rectification circuit BD1 rectification through thermistor RTH1 is by resistance R20, R21, R22, metal-oxide-semiconductor Q50 It charges to capacitor C37.When the voltage of capacitor C37 is increased to the starting voltage such as 10V or so of setting, the power supply of main control unit U1 End VCC reaches starting voltage.When capacitor C37 voltage continues to increase, the voltage between the grid G and source S of metal-oxide-semiconductor Q50 declines When to 3V or so, turned off between the drain D and source S of metal-oxide-semiconductor Q50.
Further, the power supply circuit of the present embodiment further include: the soft starting circuit E and starting electricity being connect with start-up circuit D Road D is connected and is accessed the transformer type power supply circuit G of main control unit U1.
Further, the soft starting circuit of the present embodiment includes: the divider resistance connecting with start-up circuit D and partial pressure electricity Hinder connection charging capacitor, connect with the divider resistance and be connected according to the charging situation of the charging capacitor switching tube Q70, The resistance R73 of the delay end RT of access main control unit U1 is connected with switching tube Q70 connection and according to switching tube Q70.Charging capacitor One end connect with divider resistance, the feedback end FB connection of the other end and main control unit U1.The other end of switching tube Q70 is grounded.It is main The delay end RT of control unit U1 separately passes through resistance R52 and is grounded.
Further, the divider resistance in the soft starting circuit E of the present embodiment includes: sequentially connected resistance R72, R71.Electricity Resistance one end R72 access cathode of capacitor C37, the end are simultaneously grounded.The resistance R71 other end is connect with the charging capacitor in its circuit. Charging capacitor in soft starting circuit E includes: the capacitor C70 and C71 being connected in parallel.The resistance R71 other end and capacitor C70, C71 Connection.The feedback end FB of the other end access main control unit U1 of shunt capacitance C70 and C71.Sequentially connected resistance R72 and R71 Both ends be connected with the resistance R70 and diode D70 of series connection.Capacitor is accessed in one end that resistance R70 is connect with resistance R72 The anode of the cathode of C37, its other end access diode D70.The cathode of diode D70 is connected to capacitor C70.Switching tube Q70 For N-channel MOS pipe, its grid access resistance R72 and R71 between, its source electrode access capacitor C37 cathode and ground connection.
After main control unit U1 reaches starting voltage, feedback end FB sports high level by low level, at this time capacitor C37 Negative pole end gives capacitor C70, C71 charging by R71, R72, when resistance R72 both end voltage reaches the GS threshold voltage of metal-oxide-semiconductor Q70, The DS of metal-oxide-semiconductor Q70 is connected, and is at this moment equivalent to and detects the delay end RT of resistance R73 parallel resistance R52, main control unit U1 outside After connecting resistance reduces, the switching frequency of main control unit U1 can rise, thus to the dash current of metal-oxide-semiconductor Q1, Q2 when reducing starting, Achieve the purpose that soft start.
Further, the transformer type power supply circuit G of the present embodiment includes: that the primary for the primary side that transformer T1 is arranged in is secondary Winding 1-2, the chip power-supply rectifying filter circuit being arranged on primary auxiliary winding 1-2 connect with chip power-supply rectifying filter circuit Connect and supply electricity to the reduction voltage circuit of main control unit.
The chip power-supply rectifying filter circuit of the present embodiment includes: the diode that one end 1 of primary auxiliary winding 1-2 is arranged in The electricity of the other end 2 of D30, the resistance R31 being connect with diode D30, the other end for connecting resistance R31 and primary auxiliary winding 1-2 Hold C36.
The reduction voltage circuit of the present embodiment includes: the switching tube Q30 connecting with the resistance R31, connection switch pipe Q30 another The voltage-stabiliser tube ZD30 of the other end of end and primary auxiliary winding.
The switching tube Q30 of the present embodiment is NPN triode.The both ends diode D30 are provided with series resistance R30 and capacitor C35.The both ends resistance R31 are parallel with resistance R34, and the one end resistance R31 is connect with the cathode of diode D30, its other end accesses three The collector of pole pipe Q30.Capacitor C36 is polar capacitor, and the other end of resistance R31 is the one of the collector of access triode Q30 Hold the anode of another branch's access capacitor C36 of branch.Resistance R32 is provided between the collector and base stage of triode Q30.Pressure stabilizing Pipe ZD30 is zener diode.Cathode, its emitter of the base stage access zener diode ZD30 of triode Q30 passes through diode The power end VCC of D31, resistance R33 access main control unit U1.It is drawn between the base stage of triode Q30 and the anode of diode D31 One branch accesses the low pressure detection input BO of main control unit U1 by resistance R74.Cathode, the zener diode of capacitor C36 The plus earth of ZD30.
When main control unit U1 is after start-up circuit starts, driving power switch carries out power conversion, and diode D30 will become After the ac voltage rectifier that the primary auxiliary winding 1-2 of depressor T1 is coupled to, then through R31, C36 filtering, become direct current, using three The voltage of capacitor C36 is down to after 20V the power end VCC for supplying main control unit U1 by pole pipe Q30, resistance R32, voltage-stabiliser tube ZD30, Start-up circuit D can be made to complete switch off, to reduce loss, improve power-efficient.
Further, the switching power circuit of the present embodiment further include: the EMC circuit A of current rectifying and wave filtering circuit front end is set.
The EMC circuit of the present embodiment includes: filter capacitor and common mode inductance.Filter capacitor in EMC circuit includes: to set Set X capacitor at input line both ends, the Y capacitance that is arranged between input line and ground wire.
Further, the EMC circuit of the present embodiment further include: the varistor ZNR1 between fiery zero curve is set, setting exists Resistance R2, R1 of series connection between fiery zero curve.The one end resistance R1 is connect with resistance R2, the other end accesses firewire.Resistance R2 The other end accesses zero curve.
Further, the Y capacitance of the present embodiment includes: the capacitor C23 accessed between firewire and ground wire, access firewire and ground wire Between capacitor C3, access zero curve and ground wire between capacitor C24, access zero curve and ground wire between capacitor C4.Capacitor C3 mono- End is connect with capacitor C4, its other end accesses firewire.The capacitor C4 other end accesses zero curve.X capacitor includes: access firewire or zero curve Between capacitor C1, access firewire or zero curve between C2.
Common mode inductance includes: common mode inductance LF1.The both ends of a coil of common mode inductance LF1 are respectively connected to resistance R1, capacitor The other end of C3 simultaneously accesses firewire, the both ends of another coil be respectively connected to resistance R2, capacitor C4 the other end and access zero curve.
The EMC circuit of the present embodiment further include: setting is in common mode inductance LF1 input terminal and is arranged between firewire and zero curve Varistor ZNR1.
EMC (Electro Magnetic Compatibility Electro Magnetic Compatibility) circuit passes through common mode inductance LF1 and X electricity Hold and the filtering of Y capacitance, inhibition own power switch are caused to extraneous conduction and radiation interference;Pass through varistor ZNR1 Circuit is not damaged by lightning surge voltage below for protection.
Further, the switching power circuit of the present embodiment further include: connect with current rectifying and wave filtering circuit B, detect rectification after it is defeated Enter the input voltage detection circuit C of voltage.
The input voltage detection circuit C of the present embodiment includes: the input voltage point accessed after current rectifying and wave filtering circuit rectification Divider resistance.The low pressure detection input BO of partial pressure access main control unit U1 in input voltage detection circuit C through divider resistance.
Further, the divider resistance of the input voltage detection circuit of the present embodiment include: sequentially connected resistance R45, R46、R47、R53。
Input voltage terminal, its other end after the one end resistance R45 access current rectifying and wave filtering circuit B rectification are connect with resistance R46. Preferably, resistance R45 accesses one end the Input voltage terminal of rectified circuit DB1 rectification, thermistor RTH1 output.It is defeated at this Enter voltage end to refer mainly to power voltage supply after rectifying and wave-filtering to other function circuit, the Input voltage terminal of chip.Resistance R53 with The low pressure detection input BO of main control unit U1 is accessed between R47.Resistance R53 other end ground connection.
Rectified circuit or rectifier bridge DB1 rectification after input voltage by resistance R53 and R45/R46/R47 partial pressure after, By the low pressure detection input BO of the voltage input at the both ends R53 to main control unit U1, when main control unit U1 detects that low pressure detects When the partial pressure of input terminal BO input is lower than 1V, driving is closed in main control unit U1 control, and power supply is made to enter input under-voltage protection shape State.
Further, the switching power circuit of the present embodiment further include: the remote control switching circuit O communicated with main control unit U1. The remote control switching circuit O of the present embodiment includes: remote control trigger device, the photoelectrical coupler U4 connecting with remote control trigger device.It is distant Control the trigger switch or triggering connector end CN600 of trigger device.Photoelectrical coupler U4 includes: that setting is touched in transmitting terminal and remote control The connection of hair device and because of the light emitting diode U4B of remote control trigger conducting, receive and light emitting diode U4B signal and be transferred to master control list The phototriode U4A that first U1 is controlled.The low pressure of the collector access main control unit U1 of phototriode U4A detects input Hold BO, its emitter ground connection.The ground terminal GND of main control unit U1 is grounded.
Further, the remote control switching circuit of the present embodiment further include: with the concatenated resistance R600 of light emitting diode U4B, simultaneously The resistance R601 and capacitor C601 for being associated in the both ends light emitting diode U4B and being connected in parallel.Remote control trigger is accessed in the one end resistance R600 The anode of the anode of device CN600, its other end access light emitting diode U4B.The cathode access remote control touching of light emitting diode U4B Send out the cathode of device CN600.
When the trigger switch of remote control trigger device or triggering connector end CN600 input are high level, photoelectrical coupler The light emitting diode U4B of U4 is connected, so that the phototriode U4A of receiving end be driven to be connected, the low pressure of main control unit U1 is examined The current potential for surveying input terminal BO is dragged down in 1V, so that driving is closed, output shutdown.When the trigger switch or triggering of remote control trigger device When connector end CN600 input is low level, the light emitting diode U4B shutdown of photoelectrical coupler U4 leads to the photoelectricity of receiving end The current potential of triode U4A shutdown, the low pressure detection input BO of main control unit U1 is higher than 1V, thus output driving, power supply is normal Work.
The Switching Power Supply for being 350W mainly for realization power of switching power circuit of the invention, input voltage are preferably 90~132 or 180~264VAC, rated output be 12VDC/29A or 24VDC/14.6A, this circuit have input under-voltage protection, OVP (output over-voltage protection), OCP (output overcurrent protection), OTP (over-temperature protection), the power conversion topologies used are double Pipe normal shock.
The embodiments described above only express several embodiments of the present invention, and the description thereof is more specific and detailed, but simultaneously Limitations on the scope of the patent of the present invention therefore cannot be interpreted as.It should be pointed out that for those of ordinary skill in the art For, without departing from the inventive concept of the premise, various modifications and improvements can be made, these belong to guarantor of the invention Protect range.Therefore, the scope of protection of the patent of the invention shall be subject to the appended claims.

Claims (10)

1. a kind of switching power circuit characterized by comprising current rectifying and wave filtering circuit is connect with the current rectifying and wave filtering circuit Switching circuit, the control circuit being connect with the switching circuit, the power supply circuit being connect with the control circuit and the switch The main winding of the primary side of circuit connection, is arranged at the transformer T1 times the transformer T1 that is arranged corresponding to the main winding The output circuit of grade side, be arranged in the transformer T1 primary side thermal-shutdown circuit, with the output circuit connect inspection It surveys output voltage and feeds back to the output overvoltage protection circuit that the control circuit carries out overvoltage protection, the switching circuit setting In the primary side of the transformer T1, the control circuit includes: main control unit, and the output circuit includes: to be arranged described First secondary windings of the primary side of transformer T1, the output rectifier and filter being connect with first secondary windings, setting In the load circuit of output end, the thermal-shutdown circuit includes: the cooling power supply circuit for accessing cooling device and the cooling Power supply circuit connection simultaneously adjusts output voltage according to power source temperature to adjust the cooling drive control electricity of cooling device output power Road, the cooling power supply circuit include: be arranged in the transformer T1 primary side second subprime winding, with described second The cooling current rectifying and wave filtering circuit of grade winding connection, the voltage regulation unit RG1 being connect with the cooling current rectifying and wave filtering circuit, the cooling Current rectifying and wave filtering circuit includes: the filter capacitor for connecting and supplying electricity to cooling drive control circuit or cooling device with cooling device C200, the cooling drive control circuit include: corresponding to power supply to be arranged and detect power source temperature or temperature change and according to temperature Degree variation causes the thermistor RTH3 of change in resistance, the driving resistance R220 connecting with the thermistor RTH3, is connected in parallel on Drive the capacitor C220 at the both ends resistance R220, connect with the driving resistance R220 and according to drive resistance R220 both end voltage into Voltage-stabilizing device SHR1 whether row conducting, with the voltage-stabilizing device SHR1 connection and be connected according to voltage-stabilizing device SHR1 Switching tube Q122, with the switching tube Q122 connect and supply electricity to cooling device and become according to the thermistor RTH3 resistance value Change and causes the cooling power supply capacitor C221 of voltage change, connect with cooling power supply capacitor C221 and switching tube Q122 and pass through switch Pipe Q122 supplies electricity to the capacitor C201 of cooling power supply capacitor C221, and the capacitor C201 is connect with voltage regulation unit RG1 output end, institute Thermistor RTH3 is stated to connect with driving resistance R220 and access the both ends the capacitor C201.
2. switching power circuit according to claim 1, which is characterized in that the thermistor RTH3 and driving resistance Resistance R219 is also connected between R220, the voltage-stabilizing device SHR1 is zener diode or controllable source of stable pressure, the switching tube Q122 is PNP type triode Q122, and the reference end of voltage-stabilizing device SHR1 is accessed between the driving resistance R220 and resistance R219, The capacitor C201, cooling power supply capacitor C221 are polar capacitor, the anode access capacitor C201's of the voltage-stabilizing device SHR1 Cathode, the cathode of the voltage-stabilizing device SHR1 access the base stage of triode Q122 by resistance R223, the triode Q122's Anode, its emitter of collector access cooling power supply capacitor C221 accesses the anode of capacitor C201, the cooling power supply capacitor The cathode of the cathode access capacitor C201 of C221, is provided with resistance R222 between the base stage and emitter of the triode Q122, One branch of collector branch of the triode Q122 is linked into the driving resistance R220 by diode D221, resistance R221 Between resistance R219, a branch is drawn between the resistance R219 and thermistor RTH3 by voltage-stabiliser tube ZD153 and accesses institute State output overvoltage protection circuit.
3. switching power circuit according to claim 1, which is characterized in that the output overvoltage protection circuit include: with The voltage-stabiliser tube or regulator tube group of the output circuit connection, the diode D150 and two being connect with the voltage-stabiliser tube or regulator tube group The photoelectrical coupler U3, the photoelectrical coupler U3 that pole pipe D150 connected and received over-voltage signal conduction include: that setting is emitting End and the light emitting diode U3B being connect with the voltage-stabiliser tube of output overvoltage protection circuit or regulator tube group and the light emitting diode U3B be correspondingly arranged and receive light emitting diode U3B detection signal will test signal be transferred to the main control unit so that its Carry out the photodiode U3A of overvoltage protection.
4. switching power circuit according to claim 3, which is characterized in that the output overvoltage protection circuit further include: The one-way SCR triode SCR1 being connect with the photodiode U3A, the electricity being connect with one-way SCR triode SCR1 R64, the resistance R65 in parallel with resistance R64 are hindered, the control electrode access photodiode U3A's of one-way SCR triode SCR1 Emitter is simultaneously connected according to photodiode U3A and is connected, and the other end of the resistance R64 being connected in parallel and resistance R65 access institute The power end of main control unit is stated, the minus earth of one-way SCR triode SCR1, its anode are connect with resistance R64, photoelectricity two The emitter of pole pipe U3A separately passes through resistance R66 ground connection, its collector accesses the power end of the main control unit by resistance R63, The both ends resistance R66 are parallel with capacitor C60;The voltage-stabiliser tube or regulator tube group of the output overvoltage protection circuit include: to be connected in series Zener diode ZD150, ZD151, the cathode of the zener diode ZD150 accesses the anode of the output circuit, described ZD151 cathode access zener diode ZD150 anode, the diode D150 anode access the ZD151 anode, its Cathode accesses the anode of the light emitting diode U3B by resistance R150, and the cathode of the light emitting diode U3B accesses capacitor The cathode of C201, the both ends of the light emitting diode U3B, which are provided with, is parallel with resistance R151 and capacitor C150;The cooling rectification Filter circuit includes: the diode D200 connecting with the second subprime winding, the series connection company that the both ends diode D200 are arranged in The capacitor C202 connect and resistance R207, the resistance R208 connecting with the diode D200 cathode, the both ends resistance R208 are connected in parallel on The common end access anode of filter capacitor C200 of resistance R209, resistance R208 and resistance R209, filter capacitor C200 it is negative The other end of second subprime winding and ground connection are accessed in pole, and one end access that resistance R208 is connect with the anode of filter capacitor C200 is steady The input terminal of unit R G1, the ground terminal ground connection of the voltage regulation unit RG1 are pressed, the output head anode of the output circuit passes through two The input terminal of pole pipe D201 access voltage regulation unit RG1.
5. switching power circuit according to claim 1, which is characterized in that further include: it is connect simultaneously with the output circuit The main control unit carries out constant current protection or the output of constant voltage output detection feedback is electric to feed back to for detection output voltage or electric current Road, output detection feed circuit include: the detection unit U100 for detect output voltage or electric current of the output circuit and The output circuit is connected and accessed cooperates detection output circuit output electricity with detection unit U100 in the detection unit U100 The current sampling resistor of stream, connect with the output end of the output circuit and access in the detection unit U100 with detection unit U100 cooperation carries out the voltage dividing resistance circuit of output voltage detection, the photoelectrical coupler connecting with the amplifier U100 output end U2, the detection unit U100 include: connect with the voltage dividing resistance circuit of the output detection feed circuit and the partial pressure is electric Resistance circuit partial pressure and reference voltage multilevel iudge and the amplifier that the control circuit is fed back to by photoelectrical coupler U2 U100A, with it is described output detection feed circuit current sampling resistor connect and detect the output circuit output electric current or The anti-phase input termination reference voltage of the amplifier U100B of curent change, amplifier U100A, its normal phase input end accesses and it The output electric current of the partial pressure of the voltage dividing resistance circuit of connection, the output circuit accesses amplifier U100B through current sampling resistor Inverting input terminal and its normal phase input end is accessed by capacitor C510 and is grounded, the photoelectrical coupler U2 include: setting exist Transmitting terminal connect with the output end of the amplifier U100A output end or amplifier U100B and is caused according to output voltage variation The light emitting diode U2B of curent change, be arranged in receiving end receive light emitting diode U2B detection signal will test signal biography The main control unit is defeated by so that it adjusts output voltage according to detection signal with output constant current or the phototriode of constant pressure U2A。
6. switching power circuit according to claim 5, which is characterized in that the voltage dividing resistance circuit include: with it is described The resistance R161 of the cathode output end connection of output circuit, the resistance R162, another with the resistance 162 being connect with resistance R161 End connects and changes dividing ratios to adjust the variable resistance SVR1 of output voltage setting point, be connected in parallel on the string at the both ends resistance R161 Join the resistance R160 and capacitor C160 of connection, be connected in parallel on the resistance R163 at the both ends resistance R162, another termination of variable resistance SVR1 Ground, output over-voltage protection output voltage is linked into amplifier U100A normal phase input end between the resistance R161 and resistance R162, The inverting input terminal of amplifier U100A provides the reference voltage chip SHR500 of reference voltage, amplification by resistance R503 access Anode of the output end of device U100A through diode D500, resistance R520 access light emitting diode U2B, the output of amplifier U100A End is another to access its inverting input terminal by capacitor C504, R504, and reference voltage chip SHR500 plus earth, its cathode pass through electricity Its cathode is accessed in the inverting input terminal of resistance R503 access amplifier U100A, its reference end, and reference voltage chip SHR500 cathode is another One branch is grounded by capacitor C501, and branch connects through resistance R505 between the cathode and capacitor C501 of reference voltage chip SHR500 Enter the inverting input terminal of amplifier U100B;Resistance R510 of the output electric current of the output circuit through being connected in parallel and R511 group At current sampling resistor access amplifier U100B inverting input terminal and its normal phase input end is accessed simultaneously by capacitor C510 Ground connection, the output end of amplifier U100B are being linked into the light emitting diode U2B just by resistance R520 through diode D510 Pole, its output end also pass through capacitor C512, resistance R512 feedback to the inverting input terminal of amplifier U100B;Voltage regulation unit RG1's Input terminal is linked into the power end of amplifier U100A, its output end by resistance R500 and is linked into amplifier by resistance R501 One branch of the power end of U100A, the power end of amplifier U100A is passed through by capacitor C500 ground connection, its another branch The cathode of resistance R502 access reference voltage chip SHR500;The cathode of the light emitting diode U2B is grounded.
7. according to claim 1 to switching power circuit described in 6 any one, which is characterized in that further include:
It connect and the switch isolation driving circuit of driving switch circuit work, connect simultaneously with the main winding with the switching circuit The main winding current detection circuit of main winding overcurrent is detected, the power supply circuit includes: that driving master is connect with the main control unit At the beginning of start-up circuit, the switch isolation driving circuit of control unit include: transformer T2, the T2 that transformer T2 primary side is arranged in Grade winding, connect with T2 armature winding and accesses the master control list the first secondary windings of T2 that transformer T2 primary side is arranged in T2 second subprime winding of the driving end of member to amplify the amplifying circuit of driving signal, transformer T2 primary side is arranged in, it is described Switching circuit includes: the switching tube Q1 connecting with first secondary windings of T2, opens with what the T2 second subprime winding was connect Pipe Q2 is closed, main winding is arranged between the switching tube Q1 and switching tube Q2, and the start-up circuit includes: the access rectification filter The first start-up resistor or resistance group of wave circuit, the switching tube Q50 being connect with the resistance or resistance group and the switching tube Q50 The second start-up resistor or resistance group of other end connection connect with the switching tube Q50 and are carried out according to the conducting of switching tube Q50 The power end of the main control unit is accessed in one end capacitor C37, the switching tube Q50 of charging;The main winding current detection electricity Road includes: to convert the electric current inductive reactance of voltage detecting for the electric current of main winding, connect with electric current inductive reactance one end And the capacitor C53 for accessing the resistance R60 of the test side of the main control unit and being connect with resistance R60.
8. switching power circuit according to claim 7, which is characterized in that the switching tube Q50 is according to grid and source Voltage turn-on between pole turns off its drain electrode and the N-channel MOS pipe that connect between source electrode, first start-up resistor or electricity Resistance group includes: resistance R20, R21, R22 of series connection, and R20 is accessed in the current rectifying and wave filtering circuit, the second start-up resistor or electricity Resistance group includes the zener diode ZD20 being connected in series, resistance R24, resistance R25, the cathode and resistance of zener diode ZD20 R20 is accessed after converging in the current rectifying and wave filtering circuit, and resistance R25 accesses the grid of metal-oxide-semiconductor Q50, and resistance R22 accesses metal-oxide-semiconductor Q50 Drain electrode, capacitor C37 is polar capacitor, the cathode ground connection of the source electrode access anode of capacitor C37 of metal-oxide-semiconductor Q50, capacitor C37, The grid of metal-oxide-semiconductor Q50, which separately passes through, is provided with capacitor C33, the both ends capacitor C33 between voltage-stabiliser tube ZD50 ground connection, its grid and source electrode It is parallel with resistance R26, the source electrode of metal-oxide-semiconductor Q50 separately separates the power end for accessing the main control unit and is grounded by capacitor C50; Amplifying circuit in the switch isolation driving circuit include: NPN triode Q51, PNP triode Q52, the triode Q51, The base stage of triode Q52 accesses the driving end of the main control unit, and the collector of the triode Q51 accesses the main control unit Power end, the emitter of the triode Q51 connect with the emitter of triode Q52, the emitter of the triode Q51 or The emitter of triode Q52 by capacitor C19 access T2 armature winding one end, triode Q52 collector access T2 primary around The group other end, triode Q51 collector the T2 armature winding other end is also accessed by capacitor C20, described switching tube Q1, Q2 are The enhanced metal-oxide-semiconductor of N-channel, described the first secondary windings one end T2 access grid, its other end of metal-oxide-semiconductor Q1 by resistance R11 The source electrode of metal-oxide-semiconductor Q1 is accessed, the drain electrode of metal-oxide-semiconductor Q1 accesses in the current rectifying and wave filtering circuit, and the both ends resistance R11 are parallel with series connection and connect The cathode of diode D12, the resistance R10 connect, diode D12 access the first secondary windings of T2 one end, the grid of metal-oxide-semiconductor Q1 and source It is provided with resistance R12 between pole, capacitor C13, C14 of series connection, institute are provided between the drain electrode and source electrode of the metal-oxide-semiconductor Q1 The source electrode for stating metal-oxide-semiconductor Q1 also accesses one end of main winding, and the other end of main winding accesses the leakage of metal-oxide-semiconductor Q1 by diode D10 Pole, capacitor C26 is additionally provided between main winding both ends, and the grid of metal-oxide-semiconductor Q2 accesses T2 second by resistance R15, diode D15 One end of secondary windings, the other end of T2 second subprime winding access one end of main winding, resistance R15, two by diode D11 The both ends of pole pipe D15 are parallel with resistance R14, be provided between the drain electrode and source electrode of metal-oxide-semiconductor Q2 series connection capacitor C16, C15, electric current inductive reactance include: the resistance R18 being connected in parallel, resistance R19, the one end resistance R18 by metal-oxide-semiconductor Q2 access it is main around Group, its source electrode for accessing metal-oxide-semiconductor Q2, other end ground connection.
9. switching power circuit according to claim 7, which is characterized in that further include: setting is in the rectifying and wave-filtering electricity The EMC circuit of road front end, with the current rectifying and wave filtering circuit connecting detection rectification after input voltage input voltage detection circuit, with The remote control switching circuit of the main control unit communication, the power supply circuit further include: the soft start being connect with the start-up circuit Circuit, the transformer type power supply circuit for being connect with the start-up circuit and accessing the main control unit, the soft starting circuit packet Include: the divider resistance that connect with the start-up circuit, the charging capacitor connecting with the divider resistance are connect simultaneously with the divider resistance The switching tube Q70 that is connected according to the charging situation of the charging capacitor, it is connect with the switching tube Q70 and according to switching tube Q70 Conducting accesses the resistance R73 at the delay end of the main control unit, charging capacitor one end connect with divider resistance, the other end with it is described The feedback end of main control unit connects, and the other end ground connection of the switching tube Q70, the delay end of the main control unit separately passes through resistance R52 ground connection;The transformer type power supply circuit include: be arranged in transformer T1 primary side primary auxiliary winding, be arranged first Grade auxiliary winding on chip power-supply rectifying filter circuit, connect with the chip power-supply rectifying filter circuit and supply electricity to the master The reduction voltage circuit of unit is controlled, the chip power-supply rectifying filter circuit includes: the diode that primary auxiliary winding one end is arranged in D30, the resistance R31 being connect with diode D30, the other end for connecting resistance R31 and primary auxiliary winding the other end capacitor C36, the reduction voltage circuit include: the switching tube Q30 connecting with the resistance R31, the connection switch pipe Q30 other end and primary pair The voltage-stabiliser tube ZD30 of the other end of winding, the EMC circuit include: filter capacitor and common mode inductance, in the EMC circuit Filter capacitor includes: the X capacitor that input line both ends are arranged in, the Y capacitance being arranged between input line and ground wire, the input electricity Pressure detection circuit includes: the divider resistance of the input voltage after the access current rectifying and wave filtering circuit rectification, the input voltage inspection Partial pressure in slowdown monitoring circuit through divider resistance accesses the low pressure detection input of the main control unit;The remote control switching circuit packet Include: remote control trigger device, the photoelectrical coupler U4 connecting with the remote control trigger device, the photoelectrical coupler U4 includes: to set It sets in transmitting terminal and is connected with remote control trigger device and the light emitting diode U4B that be connected by remote control trigger, setting are receiving termination Transmitting-receiving optical diode U4B signal is simultaneously transferred to the phototriode U4A that the main control unit is controlled.
10. switching power circuit according to claim 9, which is characterized in that the divider resistance in the soft starting circuit It include: sequentially connected resistance R72, R71, the cathode of the one end resistance R72 access capacitor C37, the end are simultaneously grounded, and resistance R71 is another One end is connect with the charging capacitor in its circuit, and the charging capacitor in the soft starting circuit includes: the capacitor C70 being connected in parallel With C71, the other end of shunt capacitance C70 and C71 access the feedback end of the main control unit, sequentially connected resistance R72 and R71 Both ends be provided with the resistance R70 and diode D70 of series connection, capacitor is accessed in one end that resistance R70 is connect with resistance R72 The anode of the cathode of C37, its other end access diode D70, the cathode of diode D70 are connected to capacitor C70, the switching tube Q70 be N-channel MOS pipe, its grid access resistance R72 and R71 between, its source electrode access capacitor C37 cathode and ground connection;It is described Switching tube Q30 is NPN triode, and the both ends the diode D30 are provided with series resistance R30 and capacitor C35, the both ends resistance R31 It is parallel with resistance R34, the one end resistance R31 is connect with the cathode of diode D30, its other end accesses the collector of triode Q30, Capacitor C36 is polar capacitor, the anode of the other end branch access capacitor C36 of resistance R31, the collector and base of triode Q30 Resistance R32 is provided between pole, voltage-stabiliser tube ZD30 is zener diode, and the base stage of triode Q30 accesses zener diode ZD30 Cathode, its emitter the power end of the main control unit is accessed by diode D31, resistance R33, the triode Q30's The low pressure detection input that a branch accesses the main control unit by resistance R74 is drawn between base stage and the anode of diode D31 End, the plus earth of the cathode of capacitor C36, zener diode ZD30;The EMC circuit further include: be arranged between fiery zero curve Varistor ZNR1, the series connection being arranged between fiery zero curve resistance R2, R1, the one end resistance R1 connect with resistance R2, The other end accesses firewire, and the resistance R2 other end accesses zero curve, and the Y capacitance includes: the capacitor accessed between firewire and ground wire Between capacitor C3, access zero curve between C23, access firewire and ground wire and the capacitor C24 between ground wire, access zero curve and ground wire Capacitor C4, the X capacitor includes: capacitor C1, the C2 accessed between firewire or zero curve, the one end capacitor C3 connect with capacitor C4, Its other end accesses firewire, and the capacitor C4 other end accesses zero curve, and the common mode inductance includes: common mode inductance LF1, the common mode electricity The both ends for feeling a coil of LF1 are respectively connected to resistance R1, the capacitor C3 other end and access firewire, the both ends difference of another coil Access resistance R2, capacitor C4 the other end and access zero curve, the divider resistance of the input voltage detection circuit includes: successively to connect Resistance R45, R46, R47, the R53 connect, the resistance R45 access one end the input voltage after the current rectifying and wave filtering circuit rectification End, its other end are connect with resistance R46, and the low pressure test side of the main control unit, resistance R53 are accessed between resistance R53 and R47 Other end ground connection;The collector of phototriode U4A accesses the low pressure test side of the main control unit, its emitter ground connection, main Control the ground terminal ground connection of unit;The remote control switching circuit further include: with the concatenated resistance R600 of light emitting diode U4B, in parallel Remote control trigger device is accessed in the resistance R601 being connected in parallel and capacitor C601 at the both ends light emitting diode U4B, the one end resistance R600 The anode of the anode of part CN600, its other end access light emitting diode U4B, the cathode of light emitting diode U4B access remote control trigger The cathode of device CN600.
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