CN105445608B

CN105445608B - SIC MOSFET overcurrents short-circuit detecting circuits and detection protection system

Info

Publication number: CN105445608B
Application number: CN201510854460.5A
Authority: CN
Inventors: 凌家树; 胡杰; 周强
Original assignee: Shenzhen Yingweiteng Photovoltaic Technology Co Ltd
Current assignee: Shenzhen yingweiteng Photovoltaic Technology Co. Ltd.
Priority date: 2015-11-30
Filing date: 2015-11-30
Publication date: 2018-06-12
Anticipated expiration: 2035-11-30
Also published as: CN105445608A

Abstract

This application provides a kind of SIC MOSFET overcurrents short-circuit detecting circuits and detection protection system, SIC MOSFET overcurrent short-circuit detecting circuits to include：First resistor, second resistance, the 6th resistance, the 7th resistance, the 8th resistance, the 9th resistance, the tenth resistance, the 29th resistance, the 30th resistance, third capacitance, the first diode, the second diode, the 4th diode, the 5th diode, the second triode and switch diffuser part.In this application; use the switch diffuser part with switching speed more faster than Sic MOSFET; after Sic MOSFET are opened completely; switching diffuser part can be quickly open-minded; detection circuit is enable to respond quickly to rapidly enter detection-phase; it can be quickly detected whether SIC MOSFET occur overcurrent short circuit phenomenon, improve detection speed, so as to improve protection speed of the overcurrent short-circuit protection short circuit to SIC MOSFET.

Description

SIC MOSFET overcurrents short-circuit detecting circuits and detection protection system

Technical field

This application involves field of power electronics, more particularly to a kind of SIC MOSFET overcurrents short-circuit detecting circuit and detection are protected Protecting system.

Background technology

SIC (silicon carbide) MOSFET (metal-oxide half field effect transistor, Metal-Oxide-Semiconductor Field- Effect Transistor) be the silicon carbide power switching device that relatively attracts attention at present, most apparent advantage is that：Low conducting Resistance and high-speed switch, driving circuit are simple and simultaneous with existing power device (silicon power MOSFET and IGBT) driving circuit Capacitive is good.

But present SiC MOSFET costs are higher, in practical applications, due to overload, internal drive mistake, interference Or control is improper etc. that the electric current for flowing through SiC MOSFET is caused to be far longer than the requirement of its area of safety operaton SOA, if do not had Corresponding measure deprotection or protected slowly will permanent damages costliness SiC MOSFET, therefore there is an urgent need for a kind of overcurrents at present Short-circuit detecting circuit is used for quickly detecting SiC MOSFET, with trigger short circuit over-current protection circuit to SiC MOSFET carry out and When overcurrent short-circuit protection.

Invention content

In order to solve the above technical problems, the embodiment of the present application provides a kind of SIC MOSFET overcurrents short-circuit detecting circuit and inspection Protection system is surveyed, can be quickly detected whether SIC MOSFET occur overcurrent short circuit phenomenon to reach, improve detection speed, So as to improve purpose of the overcurrent short-circuit protection short circuit to the protection speed of SIC MOSFET, technical solution is as follows：

A kind of SIC MOSFET overcurrent short-circuit detecting circuits, including：First resistor, second resistance, the 6th resistance, the 7th electricity Resistance, the 8th resistance, the 9th resistance, the tenth resistance, the 29th resistance, the 30th resistance, third capacitance, the first diode, Two diodes, the 4th diode, the 5th diode, the second triode and switch diffuser part；

The first end of the first resistor and the pwm signal output terminal of the affiliated drive circuit units of SIC MOSFET to be detected It is connected, the first end of the first resistor cathode phase with the cathode of first diode and second diode respectively Even, the second end of the first resistor respectively with the anode of first diode, the first end of the second resistance and described The first end of switch diffuser part is connected, the second end ground connection of the second resistance；

The first end of the switch diffuser part is connected with the first end of the 6th resistance, and the second of the switch diffuser part End with first driving isolated power supply positive pressure be connected, it is described switch diffuser part third end respectively with the first end of the tenth resistance and The second end of 6th resistance is connected, the second end of the tenth resistance respectively with the 7th resistance and the five or two pole The anode of pipe is connected, and the cathode of the 5th diode is connected with the drain electrode of the SIC MOSFET to be detected；

The second end of 7th resistance respectively with the first end of the 8th resistance and the anode of second diode Be connected, the first end of the 9th resistance is connected described in the second end of the 8th resistance, the first end of the 9th resistance respectively with The cathode of 4th diode is connected with the emitter of second triode, the plus earth of the 4th diode, institute The second end for stating the 9th resistance is connected with the first end of the 29th resistance, the second end difference of the 29th resistance It is connected with the first end of the 30th resistance and the base stage of second triode, the second end of the 30th resistance and the Two driving isolated power supply positive pressures are connected, and the collector of second triode crosses flow short-circuit with the SIC MOSFET's to be detected Protection output circuit is connected, the third capacitance and the 29th resistor coupled in parallel.

Preferably, the switch diffuser part is the first triode；

When the switch diffuser part is the first triode, the SIC MOSFET overcurrent short-circuit detecting circuits also wrap It includes：Third diode；

The cathode of the third diode is connected with the base stage of first triode, the anode of the third diode with The emitter of first triode is connected；

Wherein, first end of the base stage of first triode as the switch diffuser part, first triode Collector as it is described switch diffuser part second end, the emitter of first triode is as the switch diffuser The third end of part.

Preferably, it further includes：3rd resistor, the 4th resistance, the 5th resistance and the first MOSFET；

The grid of first MOSFET is connected with the second end of the first resistor, the drain electrode of the first MOSFET with The first end of the 3rd resistor is connected, and the second end of the 3rd resistor is connected with the described first driving isolated power supply positive pressure, First end of the source electrode of first MOSFET respectively with the first end of the 4th resistance and the 5th resistance is connected, described The second end ground connection of 4th resistance, the second end of the 5th resistance respectively with the base stage of first triode, the third The cathode of diode is connected with the first end of the 6th resistance.

Preferably, the switch diffuser part is the 3rd MOSFET；

When the switch diffuser part is three MOSFET, the SIC MOSFET overcurrent short-circuit detecting circuits also wrap It includes：9th diode, the 4th capacitance and the 32nd resistance；

Wherein, first end of the grid of the 3rd MOSFET as the 3rd MOSFET, the 3rd MOSFET's Drain second end as the 3rd MOSFET, the third of the source electrode of the 3rd MOSFET as the 3rd MOSFET End；

The cathode of 9th diode respectively with the drain electrode of the 3rd MOSFET and the 32nd resistance the One end is connected, and the anode of the 9th diode is connected with the described first driving isolated power supply positive pressure, the 32nd resistance Second end ground connection, the 4th capacitance and the 32nd resistor coupled in parallel.

Preferably, it further includes：33rd resistance, the 34th resistance, the tenth diode and the 2nd MOSFET；

The grid of 2nd MOSFET is connected with the second end of the first resistor, the drain electrode of the 2nd MOSFET with The first driving isolated power supply positive pressure is connected, the source electrode of the 2nd MOSFET respectively with the 33rd resistance first End is connected with the first end of the 34th resistance, the second end ground connection of the 33rd resistance, the 34th electricity The second end of resistance respectively with the grid of the 3rd MOSFET, the cathode of the tenth diode and the 6th resistance first End is connected, and the anode of the third diode is connected with the third end of first triode.

A kind of SIC MOSFET overcurrent short circuit detection and protection systems, including：Controller, crosses flow short-circuit at drive circuit unit Protect output unit, power-switching circuit and the SIC MOSFET overcurrent short-circuit detecting circuits as described in above-mentioned any one；

The controller, output PWM drive signal to the drive circuit unit and output are reset and reset signal to institute Overcurrent short-circuit protection output unit is stated, and receives the false trigger signals of the overcurrent short-circuit protection output unit output；

The drive circuit unit receives the PWM drive signal of the controller output, drives SIC to be detected MOSFET；

The SIC MOSFET overcurrents short-circuit detecting circuit is to the SIC MOSFET to be detected in the drive circuit unit It carries out overcurrent short-circuit detecting and exports false trigger signals to the overcurrent short-circuit protection output unit；

The overcurrent short-circuit protection output unit, according to the false trigger signals in the drive circuit unit SIC MOSFET carry out overcurrent short-circuit protection；

The power-switching circuit is isolated by the first driving used in the SIC MOSFET overcurrent short-circuit detecting circuits Power supply positive pressure is converted to the second driving isolated power supply positive pressure, and is supplied for the SIC MOSFET overcurrents short circuit detection and protection system Electricity.

Preferably, the drive circuit unit includes：Drive isolation optocoupler, the 16th resistance, the 4th triode, the five or three Pole pipe, the 17th resistance, the 18th resistance, the 6th diode, the 7th diode, the 8th diode, the first capacitance, the 19th electricity Resistance, SiC MOSFET to be detected, the first driving isolated power supply positive pressure and driving isolated power supply negative pressure；

The first input end of the driving isolation optocoupler is connected with the controller, and the second of the driving isolation optocoupler is defeated Enter end ground connection, the first output terminal of the driving isolation optocoupler is connected with the driving isolated power supply positive pressure, the driving isolation The second output terminal of optocoupler is connected respectively with the SIC MOSFET overcurrents short-circuit detecting circuit and the 16th resistance, described The third output terminal of isolation optocoupler is driven to be connected with the driving isolated power supply negative pressure；

The second end of 16th resistance respectively with the base stage of the 4th triode, the base stage of the 5th triode It is connected with the overcurrent short-circuit protection output unit；

The collector of 4th triode is connected with the described first driving isolated power supply positive pressure, the 4th triode First end of the emitter respectively with the emitter of the 5th triode and the 17th resistance is connected, the collection of the 5th triode Electrode is connected with the driving isolated power supply negative pressure；

The first end of 17th resistance is connected with the cathode of the 6th diode, the anode of the 6th diode It is connected with the first end of the 18th resistance, the second end of the 18th resistance and the second end phase of the 17th resistance Even；

The second end of 17th resistance respectively with the anode of the 7th diode, the moon of the 8th diode Pole, the 19th resistance first end be connected with the grid of the SIC MOSFET to be detected；

The cathode of 7th diode with it is described driving isolated power supply positive pressure be connected, the anode of the 8th diode with The driving isolated power supply negative pressure is connected, the second end ground connection of the 19th resistance, first capacitance and the described 19th Resistor coupled in parallel, the drain electrode of the SIC MOSFET to be detected is connected with the SIC MOSFET overcurrent short-circuit detecting circuits, described The source electrode ground connection of SIC MOSFET to be detected.

Preferably, the overcurrent short-circuit protection output unit includes：9th diode, the 20th resistance, the 21st electricity Resistance, the 11st resistance, the 12nd resistance, the 13rd resistance, the 14th resistance, the 15th resistance, the second triode, the three or three pole Pipe, DQ triggers, the 25th resistance, the 26th resistance, the first isolation optocoupler, the second isolation optocoupler, the 27th resistance, 28th resistance and the 31st resistance；

The anode of 9th diode is connected with the SIC MOSFET overcurrent short-circuit detecting circuits, the 9th 2 pole The cathode of pipe is connected with the first end of the 20th resistance, and the second end of the 20th resistance is respectively with the described 21st The first end of resistance is connected with the CLK pin of the DQ triggers, the second end ground connection of the 21st resistance；

The D pins of the DQ triggers are connected with the second driving isolated power supply positive pressure, the DQ triggersPin It is connected with the first end of the 31st resistance, the second end of the 31st resistance and the described second driving isolated power supply Positive pressure is connected, the DQ triggersPin is connected with the first input end of first isolation optocoupler, first isolation Second input terminal of optocoupler is connected with the first end of the 25th resistance, the second end of the 25th resistance with it is described Second driving isolated power supply positive pressure is connected；First output terminal of first isolation optocoupler respectively with the 26th resistance First end is connected with the controller, the second output terminal of first isolation optocoupler ground connection, and the of the 26th resistance Two ends are connected with third driving isolated power supply positive pressure；

The DQ triggersLight is isolated with the first end of the 27th resistance and described second respectively in pin First output terminal of coupling is connected, and the second end of the 27th resistance is connected with the described second driving isolated power supply positive pressure, institute State the second output terminal ground connection of the second isolation optocoupler, the second input terminal of second isolation optocoupler and the 28th resistance First end be connected, the second end of the 28th resistance is connected with the controller, the first of second isolation optocoupler Input end grounding；

The collector of the third transistor is connected with the drive circuit unit, the base stage of the third transistor and institute The first end for stating the 15th resistance is connected, the emitter ground connection of the third transistor, the second end point of the 15th resistance Emitter not with the first end of the 14th resistance and second triode is connected, the second end of the 14th resistance Ground connection, the collector of second triode are connected with the first end of the 12nd resistance, and the second of the 12nd resistance End drives isolated power supply positive pressure to be connected with described first, the base stage of second triode respectively with the 11st resistance the One end is connected with the first end of the 13rd resistance, the second end of the 11st resistance and the Q pin of the DQ triggers It is connected, the second end ground connection of the 13rd resistance.

Preferably, the power-switching circuit includes：22nd resistance, the 23rd resistance, the 24th resistance, Two capacitances and controllable accurate source of stable pressure；

The first end of 22nd resistance is connected with the described first driving isolated power supply positive pressure, the 22nd electricity The second end of resistance is connected with the cathode of the controllable accurate source of stable pressure, the plus earth of the controllable accurate source of stable pressure, it is described can The cathode of control precision voltage regulator is connected with the first end of the 23rd resistance, the second end difference of the 23rd resistance It is connected with the reference pole of the controllable accurate source of stable pressure and the first end of the 24th resistance, the 24th resistance Second end is grounded, and the first end of second capacitance, which is connected with the first end of the 23rd resistance and exports described second, drives Dynamic isolated power supply positive pressure, the second end ground connection of second capacitance.

Compared with prior art, the application has the beneficial effect that：

In this application, SIC MOSFET overcurrents short-circuit detecting circuit can be used to have and be opened faster than Sic MOSFET The switch diffuser part of speed is closed, since the switching speed of switch diffuser part is fast, after Sic MOSFET are opened completely, Switching diffuser part can be quickly open-minded, detection circuit is made to be enable to respond quickly to rapidly enter detection-phase, so as to fast Speed detects whether SIC MOSFET occur overcurrent short circuit phenomenon, improves detection speed, so as to improve overcurrent short-circuit protection Short circuit is to the protection speed of SIC MOSFET.

Description of the drawings

In order to illustrate more clearly of the technical solution in the embodiment of the present application, make required in being described below to embodiment Attached drawing is briefly described, it should be apparent that, the accompanying drawings in the following description is only some embodiments of the present application, for For those of ordinary skill in the art, without having to pay creative labor, it can also be obtained according to these attached drawings His attached drawing.

Fig. 1 is a kind of electronic schematic diagram for the SIC MOSFET overcurrent short-circuit detecting circuits that the application provides；

Fig. 2 is another electronic schematic diagram for the SIC MOSFET overcurrent short-circuit detecting circuits that the application provides；

Fig. 3 is a kind of course of work schematic diagram for the SIC MOSFET overcurrent short-circuit detecting circuits that the application provides；

Fig. 4 is another course of work schematic diagram for the SIC MOSFET overcurrent short-circuit detecting circuits that the application provides；

Fig. 5 is another electronic schematic diagram for the SIC MOSFET overcurrent short-circuit detecting circuits that the application provides；

Fig. 6 is another course of work schematic diagram for the SIC MOSFET overcurrent short-circuit detecting circuits that the application provides；

Fig. 7 is another course of work schematic diagram for the SIC MOSFET overcurrent short-circuit detecting circuits that the application provides；

Fig. 8 is another electronic schematic diagram for the SIC MOSFET overcurrent short-circuit detecting circuits that the application provides；

Fig. 9 is another course of work schematic diagram for the SIC MOSFET overcurrent short-circuit detecting circuits that the application provides；

Figure 10 is another course of work schematic diagram for the SIC MOSFET overcurrent short-circuit detecting circuits that the application provides；

Figure 11 is another electronic schematic diagram for the SIC MOSFET overcurrent short-circuit detecting circuits that the application provides；

Figure 12 is another course of work schematic diagram for the SIC MOSFET overcurrent short-circuit detecting circuits that the application provides；

Figure 13 is another course of work schematic diagram for the SIC MOSFET overcurrent short-circuit detecting circuits that the application provides；

Figure 14 is a kind of electronic schematic diagram for the SIC MOSFET overcurrent short circuit detection and protection systems that the application provides；

Figure 15 is a kind of electronic schematic diagram for the drive circuit unit that the application provides；

Figure 16 is a kind of electronic schematic diagram for the overcurrent short-circuit protection output unit that the application provides；

Figure 17 is a kind of electronic schematic diagram for the power-switching circuit that the application provides；

Figure 18 is a kind of logical specification figure for the DQ triggers that the application provides；

Figure 19 is a kind of work schedule schematic diagram for the SIC MOSFET overcurrent short circuit detecting systems that the application provides.

Specific embodiment

Below in conjunction with the attached drawing in the embodiment of the present application, the technical solution in the embodiment of the present application is carried out clear, complete Site preparation describes, it is clear that described embodiments are only a part of embodiments of the present application, instead of all the embodiments.It is based on Embodiment in the application, those of ordinary skill in the art are obtained every other without making creative work Embodiment shall fall in the protection scope of this application.

Embodiment one

Fig. 1 is referred to, it illustrates a kind of electrical originals for the SIC MOSFET overcurrent short-circuit detecting circuits that the application provides Schematic diagram is managed, SIC MOSFET overcurrent short-circuit detecting circuits include：First resistor R1, second resistance R2, the 6th resistance R6, the 7th Resistance R7, the 8th resistance R8, the 9th resistance R9, the tenth resistance R10, the 29th resistance R29, the 30th resistance R30, third electricity Hold C3, the first diode D1, the second diode D2, the 4th diode D4, the 5th diode D5, the second triode Q2 and switch to expand Flow device Sef.

Wherein, the first end of first resistor R1 (i.e. described first resistor R1, the first diode D1 and the second diode D2's Common end A) it is connected with the pwm signal output terminal of the affiliated drive circuit units of SIC MOSFET to be detected, the first resistor R1 Cathode of the first end respectively with the cathode of the first diode D1 and the second diode D2 be connected, the first resistor The second end of R1 respectively with the anode of the first diode D1, the first end of the second resistance R2 and the switch diffuser The first end of part Sef is connected, the second end ground connection of the second resistance R2；

The first end of the switch diffuser part Sef is connected with the first end of the 6th resistance R6, the switch diffuser part The second end of Sef is connected with the first driving isolated power supply positive pressure+VCC1, the third end of the switch diffuser part Sef respectively with The first end of tenth resistance R10 is connected with the second end of the 6th resistance R6, the second end of the tenth resistance R10 respectively with The 7th resistance R7 is connected with the anode of the 5th diode D5, the cathode of the 5th diode D5 with it is described to be detected The drain electrode of SIC MOSFET is connected；

The second end of the 7th resistance R7 respectively with the first end of the 8th resistance R8 and the second diode D2 Anode be connected, the first end of the 9th resistance R9 is connected described in the second end of the 8th resistance R8, the 9th resistance R9's Emitter of the first end respectively with the cathode of the 4th diode D4 and the second triode Q2 is connected, the four or two pole The plus earth of pipe D4, the second end of the 9th resistance R9 are connected with the first end of the 29th resistance R29, and described The second end of 29 resistance R29 respectively with the first end of the 30th resistance R30 and the base stage of the second triode Q2 It is connected, the second end of the 30th resistance R30 is connected with the second driving isolated power supply positive pressure+VCC2, second triode The collector of Q2 is connected with the overcurrent short-circuit protection output circuit of the SIC MOSFET to be detected, the third capacitance C3 and institute State the 29th resistance R29 parallel connections.

Wherein, in the present embodiment and in following embodiments, A points and the affiliated drive circuit units of SIC MOSFET to be detected Be connected, D points are connected with the drain electrode of SIC MOSFET to be detected in the affiliated drive circuit units of SIC MOSFET to be detected, C points and Overcurrent short-circuit protection output unit is connected, wherein, overcurrent short-circuit protection output unit is used to carry out SIC MOSFET to be detected Overcurrent short-circuit protection.

In this application, SIC MOSFET overcurrents short-circuit detecting circuit can be used and be had than Sic MOSFET to be detected more The switch diffuser part of fast switching speed, since the switching speed of switch diffuser part is fast, in Sic to be detected After MOSFET is opened completely, switch diffuser part can be quickly open-minded, is enable to respond quickly detection circuit to rapidly enter inspection The survey stage so as to be quickly detected whether SIC MOSFET occur overcurrent short circuit phenomenon, improves detection speed, so as to carry High protection speed of the overcurrent short-circuit protection short circuit to SIC MOSFET.

In the present embodiment, the switch diffuser part Sef is specifically as follows the first triode Q1, as shown in Figure 2.

When the switch diffuser part Sef is the first triode Q1, the SIC MOSFET overcurrent short-circuit detecting circuits It further includes：Third diode D3.

The cathode of the third diode D3 is connected with the base stage of the first triode Q1, the third diode D3's Anode is connected with the emitter of the first triode Q1.

When the switch diffuser part Sef is the first triode Q1, described in the base stage conduct of the first triode Q1 The first end of diffuser part Sef is switched, the collector of the first triode Q1 switchs the second of diffuser part Sef as described End, the emitter of the first triode Q1 is as the third end for switching diffuser part Sef.

In the present embodiment, the switching speed of the first triode Q1 is faster than the switching speed of Sic MOSFET Td to be detected, Therefore after Sic MOSFET Td to be detected are opened completely, the first triode Q1 can be quickly open-minded, enables detection circuit fast Speed response, so as to be quickly detected whether SIC MOSFET occur overcurrent short circuit phenomenon, is carried with rapidly entering detection-phase High detection speed, so as to improve protection speed of the overcurrent short-circuit protection short circuit to SIC MOSFET.Wherein, third diode D3 is used to protect the first triode Q1 emitters-base stage in order to avoid by reflected voltage being punctured.

Fig. 2 shows circuit the course of work it is as follows：As shown in figure 3, as the first resistor R1, the first diode D1 and A points in common end, that is, Fig. 3 of second diode D2 receive the PWM letters of the affiliated drive circuit units of SIC MOSFET to be detected During the high level PWM drive signal of number output terminal output, Sic MOSFET Td to be detected are first open-minded.By setting first resistor The speed of opening that R1, second resistance R2 resistance value adjust the first triode Q1 is slower than Sic MOSFET Td to be detected.Wherein, pass through The parameter designing of experiment condition makes the blanking time (when the first triode Q1 opens moment and Sic MOSFET Td to be detected and opens The difference at quarter) it adapts to the quick of Sic MOSFET Td to be detected and opens requirement.Simultaneously so that a point voltages are：Wherein the 6th resistance R6 is larger so that a point voltages V_aIt is non-that the electric current of circuit 4. is 3. flowed by circuit Often small, synergistic effect can almost be ignored.B point voltages are：V_b=V_a-V_{BE_Q1}(V_{BE_Q1}For transistor base-emitter it Between pressure drop, about 0.7V~0.8V).6th resistance R6, the tenth resistance R10 and the first triode Q1 form current amplification circuit, Ensure circuit 6. flow through the 5th diode D5 electric current it is sufficiently large and maintain the 5th diode D5 conduction voltage drop stablize.D points Voltage is the conduction voltage drop V of the 5th diode D5_D5With Sic MOSFET Td conduction voltage drops V to be detected_DSThe sum of, i.e. V_d=V_DS+ V_D5, while the maximum voltage of d points is controlled in(V_{BE_Q1}For transistor base- Pressure drop between emitter, about 0.7V~0.8V).The voltage of f points is：Such V_fMaximum value also by V_dMaximum value limitation.Second triode Q2, the 29th resistance R29, the 30th resistance R30, third capacitance C3, the second driving Isolated power supply positive pressure+VCC2 constitutes voltage monitoring circuit, and g point voltages are:

Such as Fig. 4, when the pwm signal output terminal of the affiliated drive circuit units of Sic MOSFET Td to be detected exports low level During PWM drive signal, A points become negative level-VEE, and Sic MOSFET Td shutdowns to be detected, e points voltage is by circuit at this time 1. be pulled to A point current potentials rapidly, f points also for negative pressure, the 4th diode D4 f point current potential clampers-VD4 (about -0.5~- 0.7V), to prevent voltage between the second triode Q2 base stages-emitter from exceeding maximum value required by device.While the 1st Pole pipe Q1 is by circuit 2. also rapid shutdown.When Sic MOSFET Td to be detected are turned off, a generated peak voltage part It will be reflected by the parasitic capacitance of the 5th diode D5 inside circuit, in order to discharge peak voltage, in circuit since d points It provides 2., 3. 2 circuits.SIC MOSFET overcurrents short-circuit detecting circuit provided in this embodiment can be to Sic to be detected The peak voltage that MOSFET Td are generated when rapidly switching off is to the reflected voltage of SIC MOSFET overcurrent short-circuit detecting circuits by returning The mode of road release is preferably minimized its influence the purpose even eliminated, and improves SIC MOSFET overcurrent short-circuit detecting circuits and exists Reliability, antijamming capability and adaptability in practical application.

Refer to Fig. 3, to Fig. 2 shows SIC MOSFET overcurrents short-circuit detecting circuit carry out overcurrent short-circuit detecting principle It illustrates.It is specific as follows：

In the present embodiment, SIC MOSFET overcurrents short-circuit detecting circuit utilizes Sic MOSFET Td electric conductions to be detected Bigger, the bigger characteristic of conduction voltage drop is flowed, overcurrent short-circuit detecting is carried out to Sic MOSFET Td to be detected.It is if to be detected The overcurrent short-circuit protection threshold value of Sic MOSFET Td is I_{DS_th}, corresponding conduction voltage drop threshold value is V_{DS_th}, as Sic to be detected MOSFET Td conduction voltage drops are V_{DS_th}When, the voltage of d points is V in corresponding diagram 3_{d_th}=V_{DS_th}+V_D5(V_D5Conducting pressure for D5 Drop), the maximum voltage of d points is controlled inThe voltage of f points is：V_fMaximum value also by V_dMaximum value limitation.

Second triode Q2, the 29th resistance R29, the 30th resistance R30, third capacitance C3, the second driving isolation electricity Source positive pressure+VCC2 constitutes voltage monitoring circuit, and g point voltages are:And V_{g_}Th voltages pass through the 29th resistance by+VCC2 R29, the 30th resistance R30 partial pressure gained, by the way that the 29th resistance R29, the 30th resistance R30 is set to cause

Under normal circumstances, when overcurrent or short circuit do not occur for Sic MOSFET Td to be detected, conduction voltage drop V_DSIt is small In conduction voltage drop threshold value V_{DS_th}, i.e.,：V_DS＜ V_{DS_th}, the voltage of final f points is：Second Triode Q2 is not turned on, and C points are low level, do not trigger overcurrent short-circuit protection output unit.

When overcurrent or short circuit occur for Sic MOSFET Td to be detected, conduction voltage drop V_DSMore than conduction voltage drop threshold Value V_{D_S}T, h are：V_DS＞ V_{DS_th}, the voltage of final f points is：Second triode Q2 is led Logical, C point voltages become V from low level_f-V_{CE_Q2}, and overcurrent short-circuit protection output unit is triggered with the signal, to realize to be checked Survey the overcurrent short-circuit protection of Sic MOSFET Td.

Further, it is adjustable that the SIC MOSFET overcurrent short-circuit detecting circuits that the application provides cross flow point threshold value.Wherein SIC It is as follows that MOSFET overcurrent short-circuit detecting circuits cross the adjustable principle of flow point threshold value：

Bigger, the bigger characteristic of conduction voltage drop, it is assumed that Sic according to Sic MOSFET Td conducting electric currents to be detected The overcurrent short-circuit protection threshold value of MOSFET is I_{DS_th}, corresponding conduction voltage drop threshold value is V_{DS_th}, as Sic MOSFET to be detected Td conduction voltage drops are V_{DS_th}When, the voltage of d points is V in corresponding diagram 3_{d_th}=V_{DS_th}+V_D5(V_D5Conduction voltage drop for D5), f points Voltage is：G point voltages are:And V_{g_th}Voltage by the second driving isolated power supply positive pressure+ VCC2 is by the 29th resistance R29, the 30th resistance R30 partial pressure gained, by setting the 29th resistance R29, the 30th Resistance R30 causesSo as toDue to the 7th resistance R7, the 8th resistance R8, the 9th resistance R9, V_D5, V_{BE_Q2},+VCC2 is it is known that overcurrent short-circuit protection threshold value I_{DS_th}The conduction voltage drop of corresponding Sic MOSFET Td to be detected is V_{DS_th}, by designing the 29th resistance R29, the resistance value of the 30th resistance R30 is with regard to that can adjust conduction voltage drop V_{DS_th}, so as to Enough adjust overcurrent short-circuit protection threshold value.

Embodiment two

In the present embodiment, show that the another kind for the SIC MOSFET overcurrent short-circuit detecting circuits that the application provides is electrical Principle schematic, refers to Fig. 5, SIC MOSFET overcurrents short-circuit detecting circuit provided in this embodiment Fig. 2 shows SIC It is further included on the basis of MOSFET overcurrent short-circuit detecting circuits：3rd resistor R3, the 4th resistance R4, the 5th resistance R5 and first MOSFET T1。

The grid of the first MOSFET T1 is connected with the second end of the first resistor R1, the first MOSFET T1 Drain electrode be connected with the first end of the 3rd resistor R3, the second end of the 3rd resistor R3 with described first driving electricity is isolated Source positive pressure+VCC1 is connected, the source electrode of the first MOSFET T1 first end and the described 5th with the 4th resistance R4 respectively The first end of resistance R5 is connected, the second end of the 4th resistance R4 ground connection, the second end of the 5th resistance R5 respectively with institute State the base stage of the first triode Q1, the cathode of the third diode D3 is connected with the first end of the 6th resistance R6.

In the present embodiment, only by the circuit shown in Fig. 5 with Fig. 2 shows the different operating process of circuit be described, With Fig. 2 shows the identical course of work of circuit repeat no more.It is as follows：

As shown in fig. 6, the pwm signal output terminal when the affiliated drive circuit units of SIC MOSFET to be detected exports high level During PWM drive signal, for the first MOSFET T1 when opening, the first driving isolated power supply positive pressure+VCC1 passes through the first MOSFET T1,3rd resistor R3 and the 5th resistance R5 are supplied to the bias voltage needed for base stage-emitter conducting of the first triode Q1, So that the first triode Q1 conductings.Wherein, input offset voltage of the b point voltages as the first triode Q1, wherein the 6th resistance R6 is larger so that 3. Vb points flow into that the electric current of circuit 4. is very small, and synergistic effect can almost be ignored by circuit, b points electricity It presses and is：V_b=V_a-V_{th_T1}(V_{th_T1}Conducting threshold voltage for the first MOSFET T1).5th resistance R5, the 6th resistance R6, the Ten resistance R10 and the first triode Q1 composition current amplification circuits, it is ensured that 6. electric current that the 5th diode D5 is flowed through in circuit is enough Conduction voltage drop that is big and maintaining the 5th diode D5 is stablized.The voltage of d points is the conduction voltage drop V of the 5th diode D5_D5With it is to be checked Survey Sic MOSFET Td conduction voltage drops V_DSThe sum of, i.e. V_d=V_DS+V_D5。

Such as Fig. 7, as the pwm signal output terminal output low level PWM of the affiliated drive circuit units of SIC MOSFET to be detected During drive signal, A points become negative level-VEE, Sic MOSFET Td shutdowns to be detected, at this time e points voltage by circuit 1., quilt Rapid to be pulled to A point current potentials, f points are also negative pressure, the 4th diode D4 f point current potential clampers at-VD4 (about -0.5~-0.7V), with Prevent the voltage between the second triode Q2 base stages-emitter from exceeding maximum value required by device.First MOSFET T1 simultaneously By circuit 2. also rapid shutdown, when the first MOSFET T1 are turned off, base stage-emitter of the first triode Q1 is without biased electrical Pressure and bias current, so the first triode Q1 is also simultaneously turned off.It is generated when Sic MOSFET Td to be detected are turned off A peak voltage part will be reflected by the parasitic capacitance of the 5th diode D5 inside circuit, in order to discharge peak voltage, It is provided 3. since d points in circuit, 4. two circuits, wherein, since circuit is 3. by c points, c points and the first triode Q1's Base stage is connected, and increases third diode D3 protection the first triode Q1 emitters-base stages in order to avoid being punctured by reflected voltage.

In the present embodiment, the principle that SIC MOSFET overcurrents short-circuit detecting circuit carries out overcurrent short-circuit detecting refers to implementation Referring to Fig. 3 in example one, to Fig. 2 shows SIC MOSFET overcurrents short-circuit detecting circuit carry out the principle progress of overcurrent short-circuit detecting The process of explanation, details are not described herein.

In the present embodiment, SIC MOSFET overcurrents short-circuit detecting circuit compared to embodiment one Fig. 2 shows SIC MOSFET overcurrent short-circuit detecting circuits increase 3rd resistor R3, the 4th resistance R4, the 5th resistance R5 and the first MOSFET T1, The first triode Q1 is controlled to increase the flexibility of the regulation of electrical circuit by the first MOSFET T1, circuit parameter is made to be more prone to adjust It is whole.

In the present embodiment, switch speed of the switching speed of the first MOSFET T1 equally than Sic MOSFET Td to be detected Degree is fast, therefore after Sic MOSFET Td to be detected are opened completely, the first MOSFET T1 and the first triode Q1 can be quick It is open-minded, detection circuit is made to be enable to respond quickly to rapidly enter detection-phase, is so as to be quickly detected SIC MOSFET No generation overcurrent short circuit phenomenon, improves detection speed, so as to improve guarantor of the overcurrent short-circuit protection short circuit to SIC MOSFET Protect speed.

Embodiment three

In the present embodiment, show different from Fig. 2 shows SIC MOSFET overcurrent short-circuit detecting circuits, refer to figure 8, the switch diffuser part Sef in SIC MOSFET overcurrent short-circuit detecting circuits provided in this embodiment can also be third MOSFET T3。

Switch diffuser part Sef be the 3rd MOSFET T3 when, compared to Fig. 2 shows SIC MOSFET cross flow short-circuit Detection circuit, SIC MOSFET overcurrent short-circuit detecting circuits provided in this embodiment further include：9th diode D9, the 4th capacitance C4 and the 32nd resistance R32.

Wherein, first end of the grid of the 3rd MOSFET T3 as the 3rd MOSFET, the 3rd MOSFET Second end of the drain electrode of T3 as the 3rd MOSFET T3, the source electrode of the 3rd MOSFET T3 is as the third The third end of MOSFET T3；

The cathode of the 9th diode D9 respectively with the drain electrode of the 3rd MOSFET T3 and the 32nd resistance The first end of R32 is connected, and the anode of the 9th diode D9 is connected with the described first driving isolated power supply positive pressure+VCC1, institute The second end ground connection of the 32nd resistance R32 is stated, the 4th capacitance C4 is in parallel with the 32nd resistance R32.

In the first triode Q1 during Fig. 2 is replaced by the 3rd MOSFET T3, increase the 9th diode D9, the 4th capacitance The reason of C4 and the 32nd resistance R32, is as follows：There are integration diode, Sic MOSFET Td to be detected in 3rd MOSFET T3 Peak voltage during shutdown can pass through the integration of the integrating capacitor of the 5th diode D5, the tenth resistance R10 and the 3rd MOSFET T3 Diode is added on the first driving isolated power supply positive pressure+VCC1, therefore increases the 9th diode D9, the 4th capacitance C4 and the 30th Two resistance R32 absorb peak voltage during Sic MOSFET Td to be detected shutdown, avoid the first driving isolated power supply positive pressure+ VCC1 is excessively high, influences circuit normal work.

In the present embodiment, only by the circuit shown in Fig. 8 with Fig. 2 shows the different operating process of circuit be described, With Fig. 2 shows the identical course of work of circuit repeat no more.It is as follows：

As shown in figure 9, the pwm signal output terminal when the affiliated drive circuit units of SIC MOSFET to be detected exports high level During PWM drive signal, b point voltages are：V_b=V_a-V_{th_T3}(V_{th_T3}Conducting threshold voltage for the 3rd MOSFET T3).Tenth electricity Hinder R10 and the 3rd MOSFET T3 and form current amplification circuit, it is ensured that circuit 6. flow through the 5th diode D5 electric current it is sufficiently large and The conduction voltage drop of the 5th diode D5 is maintained to stablize.The voltage of d points is the conduction voltage drop V of the 5th diode D5_D5With Sic to be detected MOSFET Td conduction voltage drops V_DSThe sum of, i.e. V_d=V_DS+V_D5, while the maximum voltage of d points is controlled inThe voltage of f points is：Such V_fMaximum value also by V_dMaximum value Limitation.

As shown in Figure 10, when the pwm signal output terminal of the affiliated drive circuit units of SIC MOSFET to be detected output it is low During level PWM drive signal, A points become negative level-VEE, and Sic MOSFET Td shutdowns to be detected, e points voltage passes through back at this time 1. road, is pulled to rapidly A point current potentials, f points are also negative pressure, the 4th diode D4 f point current potential clampers-VD4 (about -0.5~- 0.7V), to prevent voltage between the second triode Q2 base stages-emitter from exceeding maximum value required by device.Third simultaneously MOSFET T3 are by circuit 2. also rapid shutdown.When Sic MOSFET Td to be detected are turned off, generated peak voltage one Part will be reflected by the parasitic capacitance of the 5th diode D5 inside circuit, in order to discharge peak voltage, from d points in circuit Start to provide 2., 3., 5. 3 circuits.

Equally, SIC MOSFET overcurrent short-circuit detecting circuits provided in this embodiment adjustable, the SIC that crosses flow point threshold value MOSFET overcurrent short-circuit detecting circuits cross the adjustable principle of flow point threshold value, and to may refer to SIC MOSFET overcurrents in embodiment one short Alignment detection circuit crosses the adjustable principle of flow point threshold value, and details are not described herein.

In this application, SIC MOSFET overcurrents short-circuit detecting circuit has been used with than Sic MOSFET to be detected faster Switching speed the 3rd MOSFET, it is complete in Sic MOSFET to be detected since the switching speed of the 3rd MOSFET is fast After opening, the 3rd MOSFET can be quickly open-minded, and detection circuit is made to be enable to respond quickly to rapidly enter detection-phase, so as to It is enough quickly detected whether SIC MOSFET occur overcurrent short circuit phenomenon, improves detection speed, so as to improve flow short-circuit Protection short circuit is to the protection speed of SIC MOSFET.

Example IV

In the present embodiment, SIC MOSFET overcurrents short-circuit detecting circuit crosses flow short-circuit in the SIC MOSFET shown in Fig. 8 It is further included on the basis of detection circuit：33rd resistance R33, the 34th resistance R34, the tenth diode D10 and second MOSFET T2, as shown in figure 11.

The grid of the 2nd MOSFET T2 is connected with the second end of the first resistor R1, the 2nd MOSFET T2 Drain electrode be connected with the described first driving isolated power supply positive pressure+VCC1, the source electrode of the 2nd MOSFET T2 is respectively with described the The first end of 33 resistance R33 is connected with the first end of the 34th resistance R34, the 33rd resistance R33's Second end is grounded, the second end of the 34th resistance R34 respectively with the grid of the 3rd MOSFET T3, the described tenth The cathode of diode D10 is connected with the first end of the 6th resistance R6, anode and the third of the tenth diode D10 The source electrode of MOSFET T3 is connected.

In the present embodiment, only the different operating process of the circuit shown in Figure 11 and the circuit shown in Fig. 8 is described, The course of work identical with the circuit shown in Fig. 8 repeats no more.It is as follows：

As shown in figure 12, when the pwm signal output terminal of the affiliated drive circuit units of SIC MOSFET to be detected exports high electricity During flat PWM drive signal, after the 2nd MOSFET T2 are opened, input driving voltage of the b point voltages as the 3rd MOSFET T3, In the 6th resistance R6 it is larger so that 3. Vb points flow into the electric current of circuit 4. by circuit very small, and synergistic effect almost can be with Ignore, b point voltages are：V_b=V_a-V_{th_T2}(V_{th_T2}Conducting threshold voltage for the 2nd MOSFET T2).34th resistance R34, the 6th resistance R6, the tenth resistance R10 and the 3rd MOSFET T3 form current amplification circuit, it is ensured that 6. flow through the 5th in circuit The electric current of diode D5 is sufficiently large and the conduction voltage drop of the 5th diode D5 is maintained to stablize.The voltage of d points is the 5th diode D5 Conduction voltage drop V_D5With Sic MOSFET Td conduction voltage drops V to be detected_DSThe sum of, i.e. V_d=V_DS+V_D5, while the maximum electricity of d points Pressure is controlled in(V_{th_T3}Conducting threshold voltage for the 3rd MOSFET T3).

As shown in figure 13, when the pwm signal output terminal of the affiliated drive circuit units of SIC MOSFET to be detected output it is low During level PWM drive signal, A points become negative level-VEE, and Sic MOSFET Td shutdowns to be detected, e points voltage passes through back at this time 1. road, is pulled to rapidly A point current potentials, f points are also negative pressure, the 4th diode D4 f point current potential clampers-VD4 (about -0.5~- 0.7V), to prevent voltage between the second triode Q2 base stages-emitter from exceeding maximum value required by device.While second MOSFET T2 are by circuit 2. also rapid shutdown.When Sic MOSFET Td to be detected are turned off, generated peak voltage one Part will be reflected by the parasitic capacitance of the 5th diode D5 inside circuit, in order to discharge peak voltage, from d points in circuit Start to provide 3., 4., 5. 3 circuits, the tenth diode D10 also protect the 3rd MOSFET T3 grids-source electrode simultaneously in order to avoid Punctured by reflected voltage.

In the present embodiment, the switching speed of the 2nd MOSFET T2 is than the switching speed of Sic MOSFET Td to be detected Soon, therefore after Sic MOSFET Td to be detected are opened completely, the 2nd MOSFET T2 and the 3rd MOSFET T3 can be opened quickly It is logical, detection circuit is made to be enable to respond quickly to rapidly enter detection-phase, so as to whether be quickly detected SIC MOSFET Overcurrent short circuit phenomenon occurs, detection speed is improved, so as to improve protection of the overcurrent short-circuit protection short circuit to SIC MOSFET Speed.

Wherein, device is off state in the "×" indication circuit in Fig. 4, Fig. 7, Figure 10 and Figure 13.

Embodiment five

In the present embodiment, the SIC MOSFET overcurrent short circuit detection and protection systems that the application provides are shown, are referred to Figure 14, SIC MOSFET overcurrent short circuit detection and protection systems include：Controller 11, drive circuit unit 12, overcurrent short-circuit protection Output unit 13, power-switching circuit 14 and SIC MOSFET overcurrents short-circuit detecting circuit 15.

Wherein, the controller 11 respectively with the drive circuit unit 12 and the overcurrent short-circuit protection output unit 13 It is connected, for exporting, PWM drive signal is reset to the drive circuit unit 12 and output and reset signal is short to the overcurrent Output unit 13 is protected on road, and receives the false trigger signals that the overcurrent short-circuit protection output unit 13 exports.

Controller 11 is high level in the false trigger signals for receiving the output of overcurrent short-circuit protection output unit 13 When, the normal PWM drive signal that exports is receiving the overcurrent short-circuit protection output unit 13 to the drive circuit unit 12 When the false trigger signals of output are low level, stop output PWM drive signal to the drive circuit unit 12.

The drive circuit unit 12 is connected with the SIC MOSFET overcurrents short-circuit detecting circuit 15, for receiving The PWM drive signal of the output of controller 11 is stated, drives SIC MOSFET to be detected.

SIC MOSFET overcurrents short-circuit detecting circuit 15, is connected with overcurrent short-circuit protection output unit 13, for described SIC MOSFET to be detected in drive circuit unit 12 carry out overcurrent short-circuit detecting and export false trigger signals to described Overcurrent short-circuit protection output unit 13.

The concrete structure of SIC MOSFET overcurrents short-circuit detecting circuit 15 and to be checked in the drive circuit unit 12 SIC MOSFET are surveyed to carry out overcurrent short-circuit detecting and export overcurrent short-circuit detecting result to the overcurrent short-circuit protection to export list The process of member 13 refers to embodiment one to the SIC MOSFET overcurrents short-circuit detecting circuit 15 shown in example IV, herein no longer It repeats.

The overcurrent short-circuit protection output unit 13, is connected with the drive circuit unit 12, is triggered according to the failure Signal carries out overcurrent short-circuit protection to the SIC MOSFET in the drive circuit unit 12.

The power-switching circuit 14 is used for will be first used in the SIC MOSFET overcurrents short-circuit detecting circuit 15 Driving isolated power supply positive pressure+VCC1 is converted to the second driving isolated power supply positive pressure+VCC2, and short for the SIC MOSFET overcurrents Road detection protection system power supply.

In the present embodiment, the electronic schematic diagram of drive circuit unit 12 refers to Figure 15, drive circuit unit 12 Including：Drive isolation optocoupler U1, the 16th resistance R16, the 4th triode Q4, the 5th triode Q5, the 17th resistance R17, the 18 resistance R18, the 6th diode D6, the 7th diode D7, the 8th diode D8, the first capacitance C1, the 19th resistance R19, SiC MOSFET Td to be detected, the first driving isolated power supply positive pressure+VCC1 and driving isolated power supply negative pressure-VEE.

The first input end of the driving isolation optocoupler U1 is connected with the controller 11, the driving isolation optocoupler U1's Second input end grounding, the first output terminal of the driving isolation optocoupler U1 is connected with the driving isolated power supply positive pressure, described Drive the second output terminal of isolation optocoupler U1 respectively with the SIC MOSFET overcurrents short-circuit detecting circuit 15 and the described 16th Resistance R16 is connected, and the third output terminal of the driving isolation optocoupler U1 is connected with the driving isolated power supply negative pressure-VEE.

The second end of the 16th resistance R16 respectively with the base stage of the 4th triode Q4, the 5th triode The base stage of Q5 is connected with the overcurrent short-circuit protection output unit 13.

The collector of the 4th triode Q4 is connected with the described first driving isolated power supply positive pressure+VCC1, and the described 4th The emitter of the triode Q4 first end phase with the emitter of the 5th triode Q5 and the 17th resistance R17 respectively Even, the collector of the 5th triode Q5 is connected with the driving isolated power supply negative pressure-VEE.

The first end of the 17th resistance R17 is connected with the cathode of the 6th diode D6, the 6th diode The anode of D6 is connected with the first end of the 18th resistance R18, the second end and the described 17th of the 18th resistance R18 The second end of resistance R17 is connected.

The second end of the 17th resistance R17 respectively with the anode of the 7th diode D7, the 8th diode The cathode of D8, the 19th resistance R19 first end be connected with the grid of the SIC MOSFET to be detected.

The cathode of the 7th diode D7 is connected with the described first driving isolated power supply+VCC1 positive pressures, and the described 8th 2 The anode of pole pipe D8 is connected with the driving isolated power supply negative pressure-VEE, the second end ground connection of the 19th resistance R19, described First capacitance C1 is in parallel with the 19th resistance R19, drain electrode and the SIC MOSFET of the SIC MOSFET to be detected Overcurrent short-circuit detecting circuit 15 is connected, the source electrode ground connection of the SIC MOSFET to be detected.

In the present embodiment, the electronic schematic diagram of overcurrent short-circuit protection output unit 13 refers to Figure 16, and overcurrent is short Road protection output unit 13 includes：9th diode D9, the 20th resistance R20, the 21st resistance R21, the 11st resistance R11, the 12nd resistance R12, the 13rd resistance R13, the 14th resistance R14, the 15th resistance R15, the second triode Q2, third Triode Q3, DQ trigger U2, the 25th resistance R25, the 26th resistance R26, the first isolation optocoupler U3, the second isolation light Coupling U4, the 27th resistance R27, the 28th resistance R28 and the 31st resistance R31.

The anode of the 9th diode D9 is connected with the SIC MOSFET overcurrents short-circuit detecting circuit 15, and the described 9th The cathode of diode D9 is connected with the first end of the 20th resistance R20, the second end of the 20th resistance R20 respectively with The first end of the 21st resistance R21 is connected with the CLK pin of the DQ triggers U2, the 21st resistance R21 Second end ground connection.

The D pins of the DQ triggers U2 are connected with the second driving isolated power supply positive pressure+VCC2, the DQ triggers U2'sPin is connected with the first end of the 31st resistance R31, the second end of the 31st resistance R31 and described the Two driving isolated power supply positive pressure+VCC2 are connected, the DQ triggers U2'sPin and the first of the first isolation optocoupler U3 Input terminal is connected, and the second input terminal of the first isolation optocoupler U3 is connected with the first end of the 25th resistance R25, institute The second end for stating the 25th resistance R25 is connected with the described second driving isolated power supply positive pressure+VCC2.

The first output terminal of the first isolation optocoupler U3 respectively with the first end of the 26th resistance R26 and described Controller 11 is connected, the second output terminal of the first isolation optocoupler U3 ground connection, the second end of the 26th resistance R26 with Third driving isolated power supply positive pressure+VCC3 is connected, the DQ triggers U2'sPin respectively with the 27th resistance The first end of R27 is connected with the first output terminal of the second isolation optocoupler U4, the second end of the 27th resistance R27 with The second driving isolated power supply positive pressure+VCC2 is connected, the second output terminal ground connection of the second isolation optocoupler U4, and described second The second input terminal of isolation optocoupler U4 is connected with the first end of the 28th resistance R28, the 28th resistance R28's Second end is connected with the controller 11, the first input end ground connection of the second isolation optocoupler U4.

The collector of the third transistor Q3 is connected with the drive circuit unit 12, the base of the third transistor Q3 Pole is connected with the first end of the 15th resistance R15, the emitter ground connection of the third transistor Q3, the 15th resistance Emitter of the second end of R15 respectively with the first end of the 14th resistance R14 and the second triode Q2 is connected, described The second end ground connection of 14th resistance R14, the collector of the second triode Q2 and the first end of the 12nd resistance R12 It is connected, the second end of the 12nd resistance R12 is connected with the described first driving isolated power supply positive pressure+VCC1, and the described 2nd 3 First end of the base stage of pole pipe Q2 respectively with the first end of the 11st resistance R11 and the 13rd resistance R13 is connected, institute The second end for stating the 11st resistance R11 is connected with the Q pin of the DQ triggers U2, the second end of the 13rd resistance R13 Ground connection.

Wherein, the B arrows in Figure 14 represent the B output points in Figure 16 to the B input points of Figure 15.

In the present embodiment, the electronic schematic diagram of power-switching circuit 14 refers to Figure 17, power-switching circuit 14 Including：22nd resistance R22, the 23rd resistance R23, the 24th resistance R24, the second capacitance C2 and controllable accurate voltage stabilizing Source U5.

The first end of the 22nd resistance R22 is connected with the described first driving isolated power supply positive pressure+VCC1, and described the The second end of 22 resistance R22 is connected with the cathode of the controllable accurate source of stable pressure U5, the controllable accurate source of stable pressure U5's Plus earth, the cathode of the controllable accurate source of stable pressure U5 are connected with the first end of the 23rd resistance R23, and described second The second end of 13 resistance R23 respectively with the reference pole of the controllable accurate source of stable pressure U5 and the 24th resistance R24 First end is connected, the second end ground connection of the 24th resistance R24, the first end and the described 20th of the second capacitance C2 The first end of three resistance R23 is connected and exports the second driving isolated power supply positive pressure+VCC2, and the second of the second capacitance C2 End ground connection.

In the present embodiment, the course of work of SIC MOSFET overcurrent short circuit detection and protection systems is illustrated.Specifically It is as follows：

Under normal circumstances, controller 11 (resets and resets to the input Clear Input signal of DQ triggers U2 Signal) when becoming low level from high level, DQ triggers U2'sPin withPin byBecome ForIt completes to reset default step (DQ trigger U2 logics are shown in Figure 18).The Q of DQ triggers U2 draws at this time Foot output is low level, and the second triode Q2, third transistor Q3 end, and B point voltages are not influenced by third transistor Q3, Drive circuit unit 12 works normally.Pin output is high level, and the LED light of the first isolation optocoupler U3 is ended, Trip It is high level that output signal (i.e. false trigger signals) signal, which is exported to controller 11,.The CLK pin prison of DQ triggers U2 C level points are controlled, under no overcurrent or short-circuit conditions, C level points are low level, and DQ triggers U2 is failure to actuate, as SIC MOSFET When overcurrent short-circuit detecting circuit detects overcurrent or short circuit and causes C points output high level, C points high level passes through the 9th 2 pole The pipe resistance R21 of D9, the 20th resistance R20, the 21st voltage division processing trigger control end CLK, control terminal CLK capture rapidly level After rising edge so that Q pin output becomes high level, the second triode Q2, third transistor Q3 conducting, B point quilts from low level It is pulled to GND1 rapidly, so that the 4th triode Q4 cut-offs of drive circuit unit 12, the drive of Sic MOSFET Td to be detected Dynamic signal is cut off.Pin simultaneouslyOutput becomes low level from high level, and Trip output signal are become from high level Low level acts on controller 11, and controller 11 turns off PWM drive signal, avoids the 16th resistance of drive circuit unit 12 R16 is crossed to be born excessive power consumption and damages for a long time.

Main time working mechanism is following (such as Figure 19)：

At the t0 moment, controller 11 controls Clear Input signal signals to become low level from high level, completes DQ The clearing and reset of trigger U2,13 circuit output of overcurrent short-circuit protection output unit is to the signal Trip of controller 11 Output signal signals maintain high level.At the t1 moment, the PWM that controller 11 sends out Sic MOSFET Td to be detected drives Dynamic signal, signal is after the delay for the isolation optocoupler U1 that overdrives in 12 circuit A points of t2 moment drive circuit unit and B point voltages VA, VB become high level by low level, Sic MOSFET Td to be detected are driven to start open-minded.At the t3 moment, Sic to be detected MOSFET Td, which are opened, to be finished, and SIC MOSFET overcurrent short-circuit detecting circuits start to detect, due to Sic MOSFET Td to be detected The electric current Sic MOSFET Current of itself do not reach scheduled also and cross flow point, and SIC MOSFET overcurrent short-circuit detecting circuits are defeated Go out C points voltage for low level.Δ t1=t3-t2 is the front end blanking time of detection circuit, within this time, Sic to be detected MOSFET Td need to complete to open action completely.

At the t4 moment, 12 circuit A points of drive circuit unit are with B point voltages VA, VB due to being believed by PWMinput signal Number influence low level is become from high level, SIC MOSFET overcurrents short-circuit detecting circuit stops detection, at this time Sic to be detected MSOFET Td switch OFFs, Sic MOSFET Current are begun to decline, and at the t5 moment, Sic MSOFET Td to be detected are complete Shutdown.Δ t2=t5-t4 is the rear end blanking time of SIC MOSFET overcurrent short-circuit detecting circuits.

At the t6 moment, controller 11 sends out the PWM drive signal of Sic MOSFET, and signal is through overdriving isolation optocoupler U1's High level is become by low level in 12 circuit A points of t7 moment drive circuit unit and B point voltages VA, VB after delay, driving is to be checked Survey Sic MOSFET Td start open-minded.At the t8 moment, Sic MOSFET Td to be detected, which are opened, to be finished, and SIC MOSFET overcurrents are short Alignment detection circuit starts to detect.Short circuit or over-current phenomenon avoidance, electric current Sic occur for Sic MOSFET Td to be detected at this time MOSFET Current rise rapidly, at the t9 moment more than preset maximum allowable threshold current, SIC MOSFET overcurrents 13 circuit of short-circuit detecting circuit triggering overcurrent short-circuit protection output unit, C point voltages VC become high level by low level, lead to DQ Trigger U2 is acted so that drive circuit unit 12B point voltage VB are pulled to rapidly 0, and Sic MOSFET Td to be detected are closed Disconnected, electric current Sic MOSFET Current decline and are complete switched off in t10 moment Sic MOSFET Td to be detected.In t11 It carves, 13 circuit output of overcurrent short-circuit protection output unit is become to the signal Trip outputsignal of controller 11 by high level Into low level, since circuit influences, VC voltages keep high level state.

At the t12 moment, pwm signal is got in the stopping of controller 11, at the t13 moment after isolation optocoupler U1 delays of overdriving, 12 circuit A points of drive circuit unit are with B point voltages VA, VB due to being influenced by the signal of PWMinput signal by high level Become low level, SIC MOSFET overcurrents short-circuit detecting circuit stops detection, and VC voltages become low level by high level at this time, whole A protection period terminates.

At the t14 moment, controller 11 controls Clear Input signal signals to become high level by low level, in t15 Moment becomes low level from high level again, completes the clearing and reset of DQ triggers U2,13 electricity of overcurrent short-circuit protection output unit Road is exported becomes high level, circuit normal work after t16 again to the signal Trip output signal signals of controller 11 Make.

It should be noted that the A points in A points, that is, above-described embodiment in the present embodiment, the C in C points, that is, above-described embodiment Point, the D points in D points, that is, above-described embodiment.

It should be noted that each embodiment in this specification is described by the way of progressive, each embodiment weight Point explanation is all difference from other examples, and just to refer each other for identical similar part between each embodiment. For device class embodiment, since it is basicly similar to embodiment of the method, so description is fairly simple, related part is joined See the part explanation of embodiment of the method.

Finally, it is to be noted that, herein, relational terms such as first and second and the like be used merely to by One entity or operation are distinguished with another entity or operation, without necessarily requiring or implying these entities or operation Between there are any actual relationship or orders.Moreover, term " comprising ", "comprising" or its any other variant meaning Covering non-exclusive inclusion, so that process, method, article or equipment including a series of elements not only include that A little elements, but also including other elements that are not explicitly listed or further include for this process, method, article or The intrinsic element of equipment.In the absence of more restrictions, the element limited by sentence "including a ...", is not arranged Except also there are other identical elements in the process, method, article or apparatus that includes the element.

A kind of SIC MOSFET overcurrents short-circuit detecting circuit provided herein and detection protection system are carried out above It is discussed in detail, the principle and implementation of this application are described for specific case used herein, above example Explanation be merely used to help understand the present processes+and its core concept；Meanwhile for the general technology people of this field Member, according to the thought of the application, there will be changes in specific embodiments and applications, in conclusion this explanation Book content should not be construed as the limitation to the application.

Claims

1. a kind of SIC MOSFET overcurrent short-circuit detecting circuits, which is characterized in that including：First resistor, second resistance, the 6th electricity Resistance, the 7th resistance, the 8th resistance, the 9th resistance, the tenth resistance, the 29th resistance, the 30th resistance, third capacitance, first Diode, the second diode, the 4th diode, the 5th diode, the second triode and switch diffuser part；

The first end of the first resistor and the pwm signal output terminal phase of the affiliated drive circuit units of SIC MOSFET to be detected Even, cathode of the first end of the first resistor respectively with the cathode of first diode and second diode is connected, The second end of the first resistor respectively with the anode of first diode, the first end of the second resistance and the switch The first end of diffuser part is connected, the second end ground connection of the second resistance；

It is described switch diffuser part first end be connected with the first end of the 6th resistance, it is described switch diffuser part second end and First driving isolated power supply positive pressure is connected, the third end of the switch diffuser part respectively with the first end of the tenth resistance and described The second end of 6th resistance is connected, the second end of the tenth resistance respectively with the 7th resistance and the 5th diode Anode is connected, and the cathode of the 5th diode is connected with the drain electrode of the SIC MOSFET to be detected；

Anode of the second end of 7th resistance respectively with the first end of the 8th resistance and second diode is connected, The first end of the 9th resistance is connected described in the second end of 8th resistance, and the first end of the 9th resistance is respectively with described The cathode of four diodes is connected with the emitter of second triode, the plus earth of the 4th diode, and the described 9th Anode of the second end of resistance respectively with the first end of the 29th resistance and the 4th diode is connected, and described second Base stage of the second end of 19 resistance respectively with the first end of the 30th resistance and second triode is connected, and described The second end of 30 resistance with second driving isolated power supply positive pressure be connected, the collector of second triode with it is described to be detected The overcurrent short-circuit protection output circuit of SIC MOSFET is connected, the third capacitance and the 29th resistor coupled in parallel.

2. SIC MOSFET overcurrent short-circuit detecting circuits according to claim 1, which is characterized in that the switch diffuser Part is the first triode；

When the switch diffuser part is the first triode, the SIC MOSFET overcurrent short-circuit detecting circuits further include：The Three diodes；

The cathode of the third diode is connected with the base stage of first triode, the anode of the third diode with it is described The emitter of first triode is connected；

Wherein, first end of the base stage of first triode as the switch diffuser part, the collection of first triode Second end of the electrode as the switch diffuser part, the emitter of first triode is as the switch diffuser part Third end.

3. SIC MOSFET overcurrent short-circuit detecting circuits according to claim 2, which is characterized in that further include：Third electricity Resistance, the 4th resistance, the 5th resistance and the first MOSFET；

The grid of first MOSFET is connected with the second end of the first resistor, the drain electrode of the first MOSFET with it is described The first end of 3rd resistor is connected, and the second end of the 3rd resistor is connected with the described first driving isolated power supply positive pressure, described First end of the source electrode of first MOSFET respectively with the first end of the 4th resistance and the 5th resistance is connected, and the described 4th The second end ground connection of resistance, the second end of the 5th resistance respectively with the base stage of first triode, the three or two pole The cathode of pipe is connected with the first end of the 6th resistance.

4. SIC MOSFET overcurrent short-circuit detecting circuits according to claim 1, which is characterized in that the switch diffuser Part is the 3rd MOSFET；

When the switch diffuser part is three MOSFET, the SIC MOSFET overcurrent short-circuit detecting circuits further include：The Nine diodes, the 4th capacitance and the 32nd resistance；

Wherein, first end of the grid of the 3rd MOSFET as the 3rd MOSFET, the drain electrode of the 3rd MOSFET As the second end of the 3rd MOSFET, the third end of the source electrode of the 3rd MOSFET as the 3rd MOSFET；

The cathode of 9th diode respectively with the 3rd MOSFET drain electrode and the 32nd resistance first end It is connected, the anode of the 9th diode drives isolated power supply positive pressure to be connected with described first, and the of the 32nd resistance Two ends are grounded, the 4th capacitance and the 32nd resistor coupled in parallel.

5. SIC MOSFET overcurrent short-circuit detecting circuits according to claim 4, which is characterized in that further include：30th Three resistance, the 34th resistance, the tenth diode and the 2nd MOSFET；

The grid of 2nd MOSFET is connected with the second end of the first resistor, the drain electrode of the 2nd MOSFET with it is described First driving isolated power supply positive pressure is connected, the source electrode of the 2nd MOSFET respectively with the first end of the 33rd resistance and The first end of 34th resistance is connected, the second end ground connection of the 33rd resistance, the 34th resistance Second end respectively with the grid, the cathode of the tenth diode and the first end phase of the 6th resistance of the 3rd MOSFET Even, the anode of the tenth diode is connected with the source electrode of the 3rd MOSFET.

6. a kind of SIC MOSFET overcurrent short circuit detection and protection systems, which is characterized in that including：Controller, drive circuit unit, Overcurrent short-circuit protection output unit, power-switching circuit and the SIC MOSFET overcurrents as described in claim 1-5 any one Short-circuit detecting circuit；

The controller, output PWM drive signal to the drive circuit unit and output are reset and reset signal to the mistake Flow short-circuit protects output unit, and receives the false trigger signals of the overcurrent short-circuit protection output unit output；

The drive circuit unit receives the PWM drive signal of the controller output, drives SIC MOSFET to be detected；

The SIC MOSFET overcurrents short-circuit detecting circuit carries out the SIC MOSFET to be detected in the drive circuit unit Overcurrent short-circuit detecting simultaneously exports false trigger signals to the overcurrent short-circuit protection output unit；

The overcurrent short-circuit protection output unit, according to the false trigger signals to the SIC in the drive circuit unit MOSFET carries out overcurrent short-circuit protection；

The power-switching circuit, by the first driving isolated power supply used in the SIC MOSFET overcurrent short-circuit detecting circuits Positive pressure is converted to the second driving isolated power supply positive pressure, and powers for the SIC MOSFET overcurrents short circuit detection and protection system.

7. SIC MOSFET overcurrent short circuit detection and protection systems according to claim 6, which is characterized in that the driving electricity Road unit includes：Drive isolation optocoupler, the 16th resistance, the 4th triode, the 5th triode, the 17th resistance, the 18th electricity Resistance, the 6th diode, the 7th diode, the 8th diode, the first capacitance, the 19th resistance, SiC MOSFET to be detected, first Drive isolated power supply positive pressure and driving isolated power supply negative pressure；

The first input end of the driving isolation optocoupler is connected with the controller, the second input terminal of the driving isolation optocoupler Ground connection, the first output terminal of the driving isolation optocoupler are connected with the driving isolated power supply positive pressure, the driving isolation optocoupler Second output terminal be connected respectively with the SIC MOSFET overcurrents short-circuit detecting circuit and the 16th resistance, the driving The third output terminal of isolation optocoupler is connected with the driving isolated power supply negative pressure；

The second end of 16th resistance respectively with the base stage of the 4th triode, the base stage of the 5th triode and institute Overcurrent short-circuit protection output unit is stated to be connected；

The collector of 4th triode is connected with the described first driving isolated power supply positive pressure, the transmitting of the 4th triode First end of the pole respectively with the emitter of the 5th triode and the 17th resistance is connected, the collector of the 5th triode It is connected with the driving isolated power supply negative pressure；

The first end of 17th resistance is connected with the cathode of the 6th diode, the anode of the 6th diode and institute The first end for stating the 18th resistance is connected, and the second end of the 18th resistance is connected with the second end of the 17th resistance；

The second end of 17th resistance respectively with the anode, the cathode of the 8th diode, institute of the 7th diode The first end for stating the 19th resistance is connected with the grid of the SIC MOSFET to be detected；

The cathode of 7th diode with it is described driving isolated power supply positive pressure be connected, the anode of the 8th diode with it is described Driving isolated power supply negative pressure is connected, the second end ground connection of the 19th resistance, first capacitance and the 19th resistance Parallel connection, the drain electrode of the SIC MOSFET to be detected is connected with the SIC MOSFET overcurrent short-circuit detecting circuits, described to be checked Survey the source electrode ground connection of SIC MOSFET.

8. SIC MOSFET overcurrent short circuit detection and protection systems according to claim 6, which is characterized in that the overcurrent is short Road protection output unit includes：9th diode, the 20th resistance, the 21st resistance, the 11st resistance, the 12nd resistance, 13rd resistance, the 14th resistance, the 15th resistance, the second triode, third transistor, DQ triggers, the 25th resistance, 26th resistance, the first isolation optocoupler, the second isolation optocoupler, the 27th resistance, the 28th resistance and the 31st electricity Resistance；

The anode of 9th diode is connected with the SIC MOSFET overcurrent short-circuit detecting circuits, the 9th diode Cathode is connected with the first end of the 20th resistance, the second end of the 20th resistance respectively with the 21st resistance First end be connected with the CLK pin of the DQ triggers, the second end of the 21st resistance ground connection；

The D pins of the DQ triggers are connected with the second driving isolated power supply positive pressure, the DQ triggersPin with it is described The first end of 31st resistance is connected, the second end of the 31st resistance and the described second driving isolated power supply positive pressure phase Even, the DQ triggersPin is connected with the first input end of first isolation optocoupler, first isolation optocoupler Second input terminal is connected with the first end of the 25th resistance, and the second end of the 25th resistance is driven with described second Dynamic isolated power supply positive pressure is connected；First output terminal of first isolation optocoupler first end with the 26th resistance respectively Be connected with the controller, the second output terminal of first isolation optocoupler ground connection, the second end of the 26th resistance with Third driving isolated power supply positive pressure is connected；

The DQ triggersPin respectively with the first end of the 27th resistance and second isolation optocoupler One output terminal is connected, and the second end of the 27th resistance is connected with the described second driving isolated power supply positive pressure, and described second The second output terminal ground connection of isolation optocoupler, the second input terminal of second isolation optocoupler and the first of the 28th resistance End is connected, and the second end of the 28th resistance is connected with the controller, the first input end of second isolation optocoupler Ground connection；

The collector of the third transistor is connected with the drive circuit unit, the base stage of the third transistor and described the The first end of 15 resistance is connected, the emitter of third transistor ground connection, the second end of the 15th resistance respectively with The first end of 14th resistance is connected with the emitter of second triode, the second termination of the 14th resistance Ground, the collector of second triode are connected with the first end of the 12nd resistance, the second end of the 12nd resistance Be connected with the described first driving isolated power supply positive pressure, the base stage of second triode respectively with the 11st resistance first End is connected with the first end of the 13rd resistance, the second end of the 11st resistance and the Q pin phase of the DQ triggers Even, the second end ground connection of the 13rd resistance.

9. SIC MOSFET overcurrent short circuit detection and protection systems according to claim 6, which is characterized in that the power supply turns Circuit is changed to include：22nd resistance, the 23rd resistance, the 24th resistance, the second capacitance and controllable accurate source of stable pressure；

The first end of 22nd resistance is connected with the described first driving isolated power supply positive pressure, the 22nd resistance Second end is connected with the cathode of the controllable accurate source of stable pressure, the plus earth of the controllable accurate source of stable pressure, the controllable essence The cathode of close source of stable pressure is connected with the first end of the 23rd resistance, the second end of the 23rd resistance respectively with institute The reference pole for stating controllable accurate source of stable pressure is connected with the first end of the 24th resistance, and the second of the 24th resistance End ground connection, the first end of second capacitance be connected with the first end of the 23rd resistance and export it is described second drive every From power supply positive pressure, the second end ground connection of second capacitance.