CN212588317U

CN212588317U - Magnetic isolation drive circuit with multi-stage output and discharge loop thereof

Info

Publication number: CN212588317U
Application number: CN202020733903.1U
Authority: CN
Inventors: 孔维聪; 申志鹏; 王小亮
Original assignee: Mornsun Guangzhou Science and Technology Ltd
Current assignee: Mornsun Guangzhou Science and Technology Ltd
Priority date: 2020-05-07
Filing date: 2020-05-07
Publication date: 2021-02-23
Anticipated expiration: 2030-05-07

Abstract

The utility model discloses a drive circuit is kept apart to multistage output's magnetism and discharge circuit thereof, multistage output's magnetism keeps apart drive circuit and includes pulse signal output circuit, isolation driving transformer, the first main switch tube of power circuit, first electric capacity, second electric capacity, first diode, power circuit second main switch tube, third electric capacity, second diode, power circuit third main switch tube, fourth electric capacity, third diode; the control circuit samples the primary side pulse signal of the isolation driving transformer, and the control circuit switches on the trigger electronic switch to discharge the second capacitor, the third capacitor and the fourth capacitor in the output side loop.

Description

Magnetic isolation drive circuit with multi-stage output and discharge loop thereof

Technical Field

The utility model relates to a drive circuit technical field, in particular to drive circuit is kept apart to multistage magnetism.

Background

The magnetic isolation driving circuit is widely applied to driving a suspended ground switch tube, and is used for driving the main switch tube to be switched on and off by using a pulse signal output circuit and isolating the pulse signal output circuit from the driven main switch tube by using a transformer. Recent advances in many industries have placed many new demands on the design of switching power supplies. Such as higher input voltage, wider input range. Particularly, in some emerging industries, such as the photovoltaic new energy industry, the demand of the switching power supply with high input voltage and wide input range is considerable. When designing a switching power supply with a wide input, the variation range of the duty ratio of the switching power supply means the variation range of the input voltage. The size of the duty cycle variation directly determines the input range and the load capacity of the switching power supply.

A product with a wider input voltage range and a higher highest input voltage is realized by a scheme of commonly connecting multiple tubes in series, that is, a driving transformer is needed to output multiple windings to drive multiple switching tubes, and the existing output multistage magnetic isolation driving circuit is shown in fig. 1, and comprises a pulse signal output circuit, an isolation driving transformer T, a first main switching tube of a power loop, a capacitor C1, a capacitor C2, a diode D1, a second main switching tube of the power loop, a capacitor C3, a diode D2, a third main switching tube of the power loop, a capacitor C4 and a diode D3; the pulse signal output circuit is connected with a capacitor C1 and an input winding Np of the isolation driving transformer T in series to form an input side loop; the dotted terminal of the first output winding Ns1 of the isolation driving transformer T is connected to one terminal of the capacitor C2, the other terminal of the capacitor C2 is connected to the cathode of the diode D1, and a positive output terminal is also led out as a first output winding loop, the dotted terminal of the first output winding Ns1 of the isolation driving transformer T is connected to the anode of the diode D1, and a negative output terminal is led out as a first output winding loop, and the first switching tube is connected in series between the positive and negative output terminals of the first output winding loop. The dotted terminal of the second output winding Ns2 of the isolation driving transformer T is connected to one terminal of the capacitor C3, the other terminal of the capacitor C3 is connected to the cathode of the diode D2, and a positive output terminal is also led out as a second output winding loop, the dotted terminal of the second output winding Ns2 of the isolation driving transformer T is connected to the anode of the diode D2, and a negative output terminal is led out as a second output winding loop, and the second switching tube is connected in series between the positive and negative output terminals of the second output winding loop. The dotted terminal of the third output winding Ns3 of the isolation driving transformer T is connected to one terminal of the capacitor C4, the other terminal of the capacitor C4 is connected to the cathode of the diode D3, and a positive output terminal is also led out as a third output winding loop, the dotted terminal of the third output winding Ns3 of the isolation driving transformer T is connected to the anode of the diode D3, and a negative output terminal is led out as a third output winding loop, and the third switch tube is connected in series between the positive and negative output terminals of the third output winding loop. The capacitor C1 is an input side blocking capacitor, the capacitors C2, C3 and C4 are output side level shift capacitors, the transformer T is a multi-winding output magnetic isolation transformer, and the diodes D1, D2 and D3 are respectively connected with the three main switching tubes in parallel.

The problems in the prior art are as follows: when the pulse signal fails, the duty ratio is lost, so that the charge on the input side capacitor C1 cannot be released immediately, the generated bootstrap voltage is applied to the input end of the isolation transformer, the input side capacitor C1 oscillates with the isolation transformer, and accordingly, the voltage across the input side capacitor C1 begins to drop, and the voltages on the input side of the isolation transformer and the output side of the voltage isolation transformer also gradually decrease. Since the voltage across the output-side capacitors C2, C3, and C4 does not have a fast discharge loop, the voltage drops slowly, which inevitably causes the output voltage Vout to rise. When the output voltage Vout rises to the conduction threshold of the main switching tube of the power circuit, the switching tube may be operated by mistake, which may cause the power failure and even harm the personal safety of the operator.

SUMMERY OF THE UTILITY MODEL

In view of this, the utility model provides a drive circuit is kept apart to multistage magnetism can effectively solve and can lose the problem that trigger switch tube misconducted because of the duty cycle.

The above object of the present invention is achieved by the following technical solutions:

a discharge loop of a multistage output magnetic isolation drive circuit comprises a primary side control circuit and a plurality of secondary side control circuits with the same structure, wherein the input end of each secondary side control circuit is connected with the output end of the primary side control circuit in parallel, each secondary side control circuit comprises an optocoupler Q1, a first triode TR1 and a second triode TR2, the anode of a light emitting diode of the optocoupler Q1 is used as the input end of the secondary side control circuit and is used for being connected with the positive output end of the primary side control circuit, the cathode of the light emitting diode of the optocoupler Q1 is grounded, the collector of a triode of the optocoupler Q1 is connected with the base of a triode TR1, the collector of the triode TR1 is connected with the base of the triode TR2, and the emitter of the triode TR2 is led out to be used as the first; the emitter of the transistor TR1 is connected with the collector of the transistor TR2 to form a second end of the secondary side control circuit; a triode emitter of the optocoupler Q1 is led out to be used as a third end of the secondary side control circuit; the primary side control circuit comprises a triode TR7, a triode TR8, a diode D4, a resistor R1, a resistor R2 and a resistor R3, wherein the anode of the diode D4 is the input end of the primary side control circuit and is used for being connected with the positive output end of the pulse signal output circuit; the cathode of the diode D4 is connected with the base of the triode TR8 through the resistor R3, the emitter of the triode TR8 is grounded, the collector of the triode TR8 is connected with the base of the triode TR7, the emitter of the triode TR7 is connected with one end of the resistor R1, the other end of the resistor R1 is led out to serve as the output end of the primary side control circuit and is used for being connected with the secondary side control circuit, the collector of the triode TR7 is connected with the voltage source VDC1, and the resistor R2 is connected between the base and the collector of the triode TR7 in parallel.

The utility model also provides a multistage output's magnetism keeps apart drive circuit's discharge circuit, including the vice limit control circuit that a primary control circuit and a plurality of structure are the same, each vice limit control circuit's input series connection is between primary control circuit's output and ground, each vice limit control circuit includes opto-coupler Q1, first triode TR1, second triode TR2, the emitting diode positive pole of opto-coupler Q1 is as the input of vice limit control circuit, be used for being connected with primary control circuit's positive output end, opto-coupler Q1's emitting diode negative pole ground connection, opto-coupler Q1's triode collecting electrode is connected with triode TR 1's base, triode TR 1's collecting electrode is connected with triode TR 2's base, triode TR 2's projecting pole is drawn forth as vice limit control circuit's first end; the emitter of the transistor TR1 is connected with the collector of the transistor TR2 to form a second end of the secondary side control circuit; a triode emitter of the optocoupler Q1 is led out to be used as a third end of the secondary side control circuit; the primary side control circuit comprises a triode TR7, a triode TR8, a diode D4, a resistor R1, a resistor R2 and a resistor R3, wherein the anode of the diode D4 is the input end of the primary side control circuit and is used for being connected with the positive output end of the pulse signal output circuit; the cathode of the diode D4 is connected with the base of the triode TR8 through the resistor R3, the emitter of the triode TR8 is grounded, the collector of the triode TR8 is connected with the base of the triode TR7, the emitter of the triode TR7 is connected with one end of the resistor R1, the other end of the resistor R1 is led out to serve as the output end of the primary side control circuit and is used for being connected with the secondary side control circuit, the collector of the triode TR7 is connected with the voltage source VDC1, and the resistor R2 is connected between the base and the collector of the triode TR7 in parallel.

The utility model also provides a magnetic isolation driving circuit with multi-stage output, which comprises a pulse signal output circuit, an isolation driving transformer, a first main switch tube of a power loop, a first capacitor, a second capacitor, a first diode, a second main switch tube of the power loop, a third capacitor, a second diode, a third main switch tube of the power loop, a fourth capacitor and a third diode;

the pulse signal output circuit is connected with the first capacitor and the input winding of the isolation driving transformer in series to form an input side loop; the first main switch tube, the second main switch tube and the third main switch tube of the power loop are respectively connected with the second capacitor, the third capacitor, the fourth capacitor and the first output winding, the second output winding and the third output winding of the isolation driving transformer in series to form an output side loop, and the first diode, the second diode and the third diode are respectively connected with the first main switch tube, the second main switch tube and the third main switch tube of the power loop in parallel; the control circuit samples the primary side pulse signal of the isolation driving transformer, triggers the first electronic switch, the second electronic switch and the third electronic switch to be conducted, and discharges the second capacitor, the third capacitor and the fourth capacitor in the output side loop. Preferably, the first electronic switch comprises a PNP first transistor and an NPN second transistor, an emitter of the first transistor and a collector of the second transistor are connected to two ends of the second capacitor, wherein a collector of the first transistor is connected to a base of the second transistor, an emitter of the first transistor and a collector of the second transistor are further connected to a positive output terminal of the first output winding of the driving transformer, and an emitter of the second transistor is connected to a same-name terminal of the first output winding of the isolation driving transformer; the base electrode of the first triode and the negative output end of the first output winding of the driving transformer are also connected with the control circuit; preferably, the second electronic switch comprises a PNP third transistor and an NPN fourth transistor, an emitter of the third transistor and a collector of the fourth transistor are connected to two ends of the third capacitor, a collector of the third transistor and a collector of the fourth transistor are connected to a base of the fourth transistor, an emitter of the third transistor and a collector of the fourth transistor are further connected to the positive output end of the second output winding of the driving transformer, and an emitter of the fourth transistor is connected to a same-name end of the second output winding of the isolation driving transformer; the base electrode of the third triode and the negative output end of the second output winding of the driving transformer are also connected with the control circuit; preferably, the third electronic switch includes a PNP fifth transistor and an NPN sixth transistor, an emitter of the fifth transistor and a collector of the sixth transistor are connected to two ends of the fourth capacitor, a collector of the fifth transistor is connected to a base of the sixth transistor, an emitter of the fifth transistor and a collector of the sixth transistor are further connected to a positive output terminal of the third output winding of the driving transformer, and an emitter of the sixth transistor is connected to a same-name terminal of the third output winding of the isolation driving transformer; and the base electrode of the fifth triode and the negative output end of the third output winding of the driving transformer are also connected with the control circuit.

Preferably, the control circuit includes: the photoelectric conversion circuit comprises a first photoelectric coupler, a second photoelectric coupler, a third photoelectric coupler, a seventh triode, an eighth triode, a first resistor, a second resistor, a third resistor, a fifth capacitor, a first voltage source and a fourth diode; the emitter of the first photoelectric coupler is connected to the negative output end of the first output winding of the driving transformer, and the collector of the first photoelectric coupler is connected to the base of the first triode; the emitter of the second photoelectric coupler is connected to the negative output end of the second output winding of the driving transformer, and the collector of the second photoelectric coupler is connected to the base of the third triode; an emitter of the third photoelectric coupler is connected to the negative output end of the third output winding of the driving transformer, and a collector of the third photoelectric coupler is connected to a base of the fifth triode; the anodes of the primary diodes of the first photoelectric coupler, the second photoelectric coupler and the third photoelectric coupler are all connected with one end of the first resistor, and the cathodes of the primary diodes of the first photoelectric coupler, the second photoelectric coupler and the third photoelectric coupler are all grounded; an emitter of the seventh triode is connected to the other end of the first resistor, a base of the seventh triode is connected to a collector of the eighth triode, and the collector of the seventh triode is connected to the positive end of the first voltage source; the second resistor is connected between the base electrode and the collector electrode of the seventh triode in parallel; the base electrode of the eighth triode is connected to the positive output end of the pulse signal output circuit through a third resistor, and the emitting electrode of the eighth triode is grounded; the fifth capacitor is connected between the base electrode and the emitter electrode of the eighth triode in parallel; the negative end of the first voltage source is grounded; the diode further comprises a fourth diode; and the fourth diode is connected between the third resistor and the positive output end of the pulse signal output circuit, the cathode of the fourth diode is connected with the third resistor, and the anode of the fourth diode is connected with the positive output end of the output circuit.

Further, the control circuit includes: the photoelectric conversion circuit comprises a first photoelectric coupler, a second photoelectric coupler, a third photoelectric coupler, a seventh triode, an eighth triode, a first resistor, a second resistor, a third resistor, a fifth capacitor, a first voltage source and a fourth diode; the emitter of the first photoelectric coupler is connected to the negative output end of the first output winding of the driving transformer, and the collector of the first photoelectric coupler is connected to the base of the first triode; the emitter of the second photoelectric coupler is connected to the negative output end of the second output winding of the driving transformer, and the collector of the second photoelectric coupler is connected to the base of the third triode; an emitter of the third photoelectric coupler is connected to the negative output end of the third output winding of the driving transformer, and a collector of the third photoelectric coupler is connected to a base of the fifth triode; the anode of the first photoelectric coupler is connected with one end of the first resistor, the cathode of the first photoelectric coupler is connected with the anode of the second photoelectric coupler, the cathode of the second photoelectric coupler is connected with the anode of the third photoelectric coupler, and the cathode of the third photoelectric coupler is grounded; an emitter of the seventh triode is connected to the other end of the first resistor, a base of the seventh triode is connected to a collector of the eighth triode, and the collector of the seventh triode is connected to the positive end of the first voltage source; the second resistor is connected between the base electrode and the collector electrode of the seventh triode in parallel; the base electrode of the eighth triode is connected to the positive output end of the pulse signal output circuit through a third resistor, and the emitting electrode of the eighth triode is grounded; the fifth capacitor is connected between the base electrode and the emitter electrode of the eighth triode in parallel; the negative end of the first voltage source is grounded; the diode further comprises a fourth diode; and the fourth diode is connected between the third resistor and the positive output end of the pulse signal output circuit, the cathode of the fourth diode is connected with the third resistor, and the anode of the fourth diode is connected with the positive output end of the output circuit.

Drawings

FIG. 1 is a schematic diagram of a conventional multi-output magnetically isolated drive circuit;

fig. 2-1 is a schematic diagram of a magnetic isolation driving circuit with multi-stage output according to a first embodiment of the present invention, in which an access point of a discharging loop in the magnetic isolation driving circuit is marked;

fig. 2-2 is a schematic diagram of a discharge circuit of a magnetic isolation driving circuit with multi-stage output according to a first embodiment of the present invention;

fig. 3 is a schematic diagram of a discharge circuit of a magnetic isolation driving circuit with multi-stage output according to a second embodiment of the present invention.

Detailed Description

First embodiment

Fig. 2-1 and 2-2 are schematic diagrams of a discharging loop of the magnetic isolation driving circuit according to the first embodiment of the present invention, a discharging loop of the magnetic isolation driving circuit according to the multistage output, a first electronic switch of the discharging loop is a PNP transistor TR1 and an NPN transistor TR2, and an emitter of the transistor TR2 is led out as a first end of a secondary side of the first discharging loop, and is used for being connected to a dotted end 101 (i.e., a first end of a second capacitor C2) of a first output winding of the magnetic isolation driving circuit; the emitter of the transistor TR1 is connected in parallel with the collector of the transistor TR2 to form a second end of the secondary side of the first discharge loop for connection to the positive output terminal 102 of the first output winding (i.e., the second end of the second capacitor C2).

The second electronic switch of the discharge circuit is a PNP type triode TR3 and an NPN type triode TR4, and an emitter of the triode TR4 is led out to be used as a first end of a secondary side of the second discharge circuit and is used for being connected with a homonymous end 201 (namely, a first end of a third capacitor C3) of a second output winding of the magnetic isolation driving circuit; the emitter of the transistor TR3 is connected in parallel with the collector of the transistor TR4 to form a second end of the secondary side of the second discharge loop for connection to the positive output terminal 202 of the second output winding (i.e., the second end of the third capacitor C3). The third electronic switch of the discharge loop is a PNP type triode TR5 and an NPN type triode TR6, and an emitter of the triode TR6 is led out to be used as a first end of a secondary side of the third discharge loop and is used for being connected with a dotted end 301 (namely, a first end of a third capacitor C3) of a third output winding of the magnetic isolation driving circuit; the emitter of the transistor TR5 is connected in parallel with the collector of the transistor TR6 to form a second end of the secondary side of the third discharge loop, for connection with the positive output terminal 302 of the third output winding (i.e., the second end of the fourth capacitor C4). The control circuit of the first electronic switch of the discharge loop further comprises a first photoelectric coupler Q1, a second photoelectric coupler Q2, a third photoelectric coupler Q3, a seventh triode TR7, an eighth triode TR8, a first resistor R1, a second resistor R2, a third resistor R3, a first voltage source VDC1 and a fourth diode D4; an emitter of the first photoelectric coupler Q1 is connected to the negative output terminal 103 of the first output winding of the driving transformer T of the magnetic isolation driving circuit (i.e. the synonym terminal of the first output winding of the transformer T), and a collector is connected to the base of the first triode TR 1; an emitter of the second photocoupler Q2 is connected to the negative output terminal 203 of the second output winding of the driving transformer T of the magnetic isolation driving circuit (i.e. the synonym terminal of the second output winding of the transformer T), and a collector is connected to the base of the third transistor TR 3; an emitter of the third photocoupler Q3 is connected to the negative output end 303 of the third output winding of the driving transformer T (i.e. the synonym end of the third output winding of the transformer T) of the magnetic isolation driving circuit, and a collector is connected to the base of the fifth triode TR 5; the anodes of the primary diodes of the first photoelectric coupler Q1, the second photoelectric coupler Q2 and the third photoelectric coupler Q3 are all connected with one end of a first resistor R1, and the cathodes of the primary diodes of the first photoelectric coupler Q1, the second photoelectric coupler Q2 and the third photoelectric coupler Q3 are all grounded; an emitter of the seventh transistor TR7 is connected to the other end of the first resistor R1, a base of the seventh transistor TR7 is connected to a collector of the eighth transistor TR8, and the collector of the seventh transistor is connected to the positive terminal of a first voltage source VDC 1; the second resistor R2 is connected in parallel between the base and the collector of the seventh triode TR 7; the base electrode of the eighth triode TR8 is connected to the positive output end 401 of the pulse signal output circuit through a third resistor R3, and the emitter electrode of the eighth triode TR8 is grounded; a fourth diode D4; the fourth diode D4 is connected between the third resistor R3 and the positive output terminal 401 of the pulse signal output circuit, the cathode of the fourth diode D4 is connected to the third resistor R3, and the anode of the fourth diode D4 is connected to the positive output terminal 401 of the pulse signal output circuit.

The working principle of the discharge circuit of the magnetic isolation driving circuit is as follows: when the primary side pulse signal is at a high level, the capacitor C5 is charged through the fourth diode D4, and the voltage of the capacitor C5 gradually rises; when the voltage of the capacitor C5 rises to the B-E junction turn-on voltage of transistor TR8, transistor TR8 is saturated. At the moment, the base electrode of the transistor TR7 is connected to the ground through the C-E junction of the transistor TR 8; the transistor TR7 is turned off. When the primary pulse signal is at a low level, the capacitor C5 continues to provide a conducting voltage to the transistor TR8 by its stored charge. The current limiting resistor R1 is used for adjusting the discharging speed of the capacitor C5. The capacitor C5 is constant, the value of the current limiting resistor R1 is increased, and the discharge time of the capacitor C5 is increased. The value of the current limiting resistor R1 is reduced, and the discharge time of the capacitor C5 is shortened. In the scheme, the discharge time of the capacitor C5 is only required to be 2 to 3 times of the pulse period. When the primary side pulse signal is lost and the time exceeds the time that the capacitor C5 keeps the transistor TR8 on, the transistor TR8 is turned off. The input voltage source VDC1 injects charge through a current limiting resistor R1 into the base of the transistor TR7 and the transistor TR7 is turned on. Meanwhile, the input voltage source VDC1 injects current to the primary leds of the photocouplers Q1, Q2, Q3 through the transistor TR7 and the current limiting resistor R1. The primary current signal promotes the secondary side of the photoelectric coupler to be conducted through the optical coupling effect of the photoelectric coupler. At this time, the level shift capacitors C2, C3 and C4 on the secondary side of the magnetic isolation transformer store electric charges, the voltages on the capacitors C2, C3 and C4 inject current to the bases of the switching transistors TR2, TR4 and TR6 through the conduction paths of the switching transistors TR1, TR3 and TR5 on the secondary side of the photoelectric coupler, the switching transistors TR2, TR4 and TR6 are turned on, and a quick discharge path is provided for the capacitors C2, C3 and C4. So far, the scheme finishes the energy discharge of the capacitors C2, C3 and C4.

The utility model discloses the magnetic isolation drive circuit's of multistage output discharge circuit, including connecting respectively in isolation driving transformer T first, second and third output winding's electronic switch, and connect in the input control circuit that the pulse signal output circuit on isolation driving transformer primary side formed, take a sample to isolation driving transformer primary side pulse signal through input control circuit, input control circuit will trigger output winding first, the second, third electronic switch switches on, second in the output side return circuit respectively, third and fourth electric capacity implement to discharge. The utility model discloses an input side pulse signal detects and to realize equally that it discharges to output side second electric capacity, third electric capacity and fourth electric capacity through three discharge circuit when duty cycle changes or loses, consequently can effectively solve the problem that triggers the switch tube mistake and switch on because of the duty cycle loses.

Second embodiment

Fig. 3 shows a schematic diagram of a discharge circuit of a magnetic isolation driving circuit according to a second embodiment of the present invention, which is based on the first embodiment of the present invention, and the second embodiment of the present invention changes the connection mode of the primary led of the photocoupler Q1, Q2, Q3: namely, the anode of the first photoelectric coupler Q1 is connected with one end of a first resistor R1, the cathode of the first photoelectric coupler Q1 is connected with the anode of the second photoelectric coupler Q2, the cathode of the second photoelectric coupler Q2 is connected with the anode of the third photoelectric coupler Q3, and the cathode of the third photoelectric coupler Q3 is grounded; other connection modes are the same as the first embodiment, and the working principle is also the same as the first embodiment, which is not described herein again.

The above is only the preferred embodiment of the present invention, it should be noted that the above preferred embodiment should not be considered as limiting the present invention, and for those skilled in the art, without departing from the spirit and scope of the present invention, several improvements and decorations can be made, and this embodiment adopts the three-stage isolation driving as the embodiment, and if it is two-stage or multi-stage, these improvements and decorations should also be considered as the protection scope of the present invention, and no description of the embodiment is needed, and the protection scope of the present invention should be subject to the scope defined by the claims.

Claims

1. The utility model provides a multistage output's magnetic isolation drive circuit's discharge circuit which characterized in that:

the secondary side control circuit comprises an optocoupler Q1, a first triode TR1 and a second triode TR2, wherein the anode of a light emitting diode of the optocoupler Q1 is used as the input end of the secondary side control circuit and is used for being connected with the positive output end of the primary side control circuit, the cathode of the light emitting diode of the optocoupler Q1 is grounded, the collector of a triode of the optocoupler Q1 is connected with the base of a triode TR1, the collector of the triode TR1 is connected with the base of the triode TR2, and the emitter of the triode TR2 is led out to be used as the first end of the secondary side control circuit; the emitter of the transistor TR1 is connected with the collector of the transistor TR2 to form a second end of the secondary side control circuit; a triode emitter of the optocoupler Q1 is led out to be used as a third end of the secondary side control circuit;

the primary side control circuit comprises a triode TR7, a triode TR8, a diode D4, a resistor R1, a resistor R2 and a resistor R3, wherein the anode of the diode D4 is the input end of the primary side control circuit and is used for being connected with the positive output end of the pulse signal output circuit; the cathode of the diode D4 is connected with the base of the triode TR8 through the resistor R3, the emitter of the triode TR8 is grounded, the collector of the triode TR8 is connected with the base of the triode TR7, the emitter of the triode TR7 is connected with one end of the resistor R1, the other end of the resistor R1 is led out to serve as the output end of the primary side control circuit and is used for being connected with the secondary side control circuit, the collector of the triode TR7 is connected with the voltage source VDC1, and the resistor R2 is connected between the base and the collector of the triode TR7 in parallel.

2. The utility model provides a multistage output's magnetic isolation drive circuit's discharge circuit which characterized in that:

the circuit comprises a primary side control circuit and a plurality of secondary side control circuits with the same structure, wherein the input end of each secondary side control circuit is connected between the output end of the primary side control circuit and the ground in series, each secondary side control circuit comprises an optocoupler Q1, a first triode TR1 and a second triode TR2, the anode of a light emitting diode of the optocoupler Q1 is used as the input end of the secondary side control circuit and is used for being connected with the positive output end of the primary side control circuit, the cathode of the light emitting diode of the optocoupler Q1 is grounded, the collector of a triode of the optocoupler Q1 is connected with the base of a triode TR1, the collector of the triode TR1 is connected with the base of the triode TR2, and the emitter of the triode TR2 is led out; the emitter of the transistor TR1 is connected with the collector of the transistor TR2 to form a second end of the secondary side control circuit; a triode emitter of the optocoupler Q1 is led out to be used as a third end of the secondary side control circuit;

3. A magnetic isolation driving circuit with multi-stage output comprises a pulse signal output circuit, an isolation driving transformer, a first main switch tube of a power circuit, a first capacitor, a second capacitor, a first diode, a second main switch tube of the power circuit, a third capacitor, a second diode, a third main switch tube of the power circuit, a fourth capacitor and a third diode; the pulse signal output circuit is connected with the first capacitor and the input winding of the isolation driving transformer in series to form an input side loop; the first main switch tube of the power loop, the second capacitor and the first output winding of the isolation driving transformer are connected in series to form a first output winding loop, the anode of the first diode is connected with the negative output end of the first output winding loop, and the cathode of the first diode is connected with the positive output end of the first output winding loop; the second main switch tube of the power loop is connected with the third capacitor and the second output winding of the isolation driving transformer in series to form a second output winding loop, the anode of the second diode is connected with the negative output end of the second output winding loop, and the cathode of the second diode is connected with the positive output end of the second output winding loop; the third main switch tube of the power loop is connected with the fourth capacitor and the third output winding of the isolation driving transformer in series to form a third output winding loop, the anode of the third diode is connected with the negative output end of the third output winding loop, and the cathode of the third diode is connected with the positive output end of the third output winding loop, which is characterized in that:

the control circuit samples a primary side pulse signal of the isolation driving transformer, triggers the first electronic switch, the second electronic switch and the third electronic switch to be conducted, and respectively discharges the second capacitor, the third capacitor and the fourth capacitor in the output side loop;

the first electronic switch comprises a PNP type first triode and an NPN type second triode, an emitting electrode of the first triode and a collecting electrode of the second triode are connected in parallel at two ends of the second capacitor, wherein the collecting electrode of the first triode is connected to a base electrode of the second triode, the emitting electrode of the first triode and the collecting electrode of the second triode are further connected to a positive output end of the first output winding of the driving transformer, and the emitting electrode of the second triode is connected with a homonymous end of the first output winding of the isolation driving transformer; the base electrode of the first triode and the negative output end of the first output winding of the driving transformer are also connected with the control circuit;

the second electronic switch comprises a PNP type third triode and an NPN type fourth triode, an emitting electrode of the third triode and a collecting electrode of the fourth triode are connected with two ends of the third capacitor in parallel, wherein the collecting electrode of the third triode is connected with a base electrode of the fourth triode, the emitting electrode of the third triode and the collecting electrode of the fourth triode are also connected with a positive output end of the second output winding of the driving transformer, and the emitting electrode of the fourth triode is connected with a homonymous end of the second output winding of the isolation driving transformer; the base electrode of the third triode and the negative output end of the second output winding of the driving transformer are also connected with the control circuit;

the third electronic switch comprises a PNP type fifth triode and an NPN type sixth triode, an emitting electrode of the fifth triode and a collecting electrode of the sixth triode are connected in parallel at two ends of the fourth capacitor, wherein the collecting electrode of the fifth triode is connected to a base electrode of the sixth triode, the emitting electrode of the fifth triode and the collecting electrode of the sixth triode are further connected to a positive output end of a third output winding of the driving transformer, and the emitting electrode of the sixth triode is connected to a homonymous end of the third output winding of the isolation driving transformer; and the base electrode of the fifth triode and the negative output end of the third output winding of the driving transformer are also connected with the control circuit.

4. The multi-output magnetically isolated drive circuit of claim 3, wherein: the control circuit includes: the photoelectric conversion circuit comprises a first photoelectric coupler, a second photoelectric coupler, a third photoelectric coupler, a seventh triode, an eighth triode, a first resistor, a second resistor, a third resistor, a fifth capacitor and a first voltage source; the emitter of the first photoelectric coupler is connected to the negative output end of the first output winding of the driving transformer, and the collector of the first photoelectric coupler is connected to the base of the first triode; the emitter of the second photoelectric coupler is connected to the negative output end of the second output winding of the driving transformer, and the collector of the second photoelectric coupler is connected to the base of the third triode; an emitter of the third photoelectric coupler is connected to the negative output end of the third output winding of the driving transformer, and a collector of the third photoelectric coupler is connected to a base of the fifth triode; the anodes of the primary diodes of the first photoelectric coupler, the second photoelectric coupler and the third photoelectric coupler are all connected with one end of the first resistor, and the cathodes of the primary diodes of the first photoelectric coupler, the second photoelectric coupler and the third photoelectric coupler are all grounded; an emitter of the seventh triode is connected to the other end of the first resistor, a base of the seventh triode is connected to a collector of the eighth triode, and the collector of the seventh triode is connected to the positive end of the first voltage source; the second resistor is connected between the base electrode and the collector electrode of the seventh triode in parallel; the base electrode of the eighth triode is connected to the positive output end of the pulse signal output circuit through a third resistor, and the emitting electrode of the eighth triode is grounded; the fifth capacitor is connected between the base electrode and the emitter electrode of the eighth triode in parallel; the negative end of the first voltage source is grounded; the diode further comprises a fourth diode; and the fourth diode is connected between the third resistor and the positive output end of the pulse signal output circuit, the cathode of the fourth diode is connected with the third resistor, and the anode of the fourth diode is connected with the positive output end of the output circuit.

5. The multi-output magnetically isolated drive circuit of claim 3, wherein: the control circuit includes: the photoelectric conversion circuit comprises a first photoelectric coupler, a second photoelectric coupler, a third photoelectric coupler, a seventh triode, an eighth triode, a first resistor, a second resistor, a third resistor, a fifth capacitor and a first voltage source; the emitter of the first photoelectric coupler is connected to the negative output end of the first output winding of the driving transformer, and the collector of the first photoelectric coupler is connected to the base of the first triode; the emitter of the second photoelectric coupler is connected to the negative output end of the second output winding of the driving transformer, and the collector of the second photoelectric coupler is connected to the base of the third triode; an emitter of the third photoelectric coupler is connected to the negative output end of the third output winding of the driving transformer, and a collector of the third photoelectric coupler is connected to a base of the fifth triode; the anode of the first photoelectric coupler is connected with one end of the first resistor, the cathode of the first photoelectric coupler is connected with the anode of the second photoelectric coupler, the cathode of the second photoelectric coupler is connected with the anode of the third photoelectric coupler, and the cathode of the third photoelectric coupler is grounded; an emitter of the seventh triode is connected to the other end of the first resistor, a base of the seventh triode is connected to a collector of the eighth triode, and the collector of the seventh triode is connected to the positive end of the first voltage source; the second resistor is connected between the base electrode and the collector electrode of the seventh triode in parallel; the base electrode of the eighth triode is connected to the positive output end of the pulse signal output circuit through a third resistor, and the emitting electrode of the eighth triode is grounded; the fifth capacitor is connected between the base electrode and the emitter electrode of the eighth triode in parallel; the negative end of the first voltage source is grounded; the diode further comprises a fourth diode; and the fourth diode is connected between the third resistor and the positive output end of the pulse signal output circuit, the cathode of the fourth diode is connected with the third resistor, and the anode of the fourth diode is connected with the positive output end of the output circuit.