CN201898324U

CN201898324U - IGBT (Insulated Gate Bipolar Transistor) drive circuit

Info

Publication number: CN201898324U
Application number: CN2010205777362U
Authority: CN
Inventors: 展鑫; 王立华
Original assignee: Shandong University of Science and Technology
Current assignee: Shandong University of Science and Technology
Priority date: 2010-10-14
Filing date: 2010-10-14
Publication date: 2011-07-13
Anticipated expiration: 2020-10-14

Abstract

The utility model relates to an IGBT (Insulated Gate Bipolar Transistor) drive circuit which comprises a switching power supply module based on a UC3845 chip and a drive module based on an EXB841 chip. The switching power supply module with the UC3845 chip as a core outputs DC (direct current) voltage of +20V and +12V to the drive module and meanwhile provides a power supply to other parts of the circuit. Under normal circumstances, when current flows through a pin 14 and a pin 15 at the signal input end of the EXB841 chip, a pin 3 of the EXB841 chip provides a drive signal to the IGBT drive circuit so that the IGBT drive circuit is switched on; when no current flows through the pin 14 and the pin 15 at the signal input end of the EXB841 chip due to a control circuit, the electric potential of the pin 3 of the EXB841 chip can quickly decrease to the switched-off one (5V lower than that of a pin 1 of the EXB841 chip) so that the IGBT drive circuit can be reliably switched off. When over-current is caused, the EXB841chip can prevent the inputting of an input signal; meanwhile, the electric potential of the pin 3 of the EXB841 chip gradually decreases to slowly switch off the IGBT drive circuit, thereby protecting the IGBT drive circuit.

Description

A kind of IGBT drive circuit

Technical field

The utility model relates to IGBT control technology field, relates in particular to IGBT and drives protection module

Background technology

IGBT (igbt) has the new-type element of the ability of the handle high voltages of bipolar transistor, big electric current again as a kind of high-speed switching capability of existing power MOSFET, and its application also comes extensive more.

And the performance of element normally in the design decision of drive circuit.In addition, the IGBT module may be because abnormal conditions such as overvoltage, overcurrent and impaired.The gate drive circuit of IGBT influence the IGBT device on-state voltage drop, switching time, switching loss, bear parameters such as short circuit current ability, determined the static state and the dynamic characteristic of IGBT device.So the appropriate design of IGBT protective circuit is also most important.

Present existing IGBT drive circuit majority is based on chip for driving EXB841; EX841 high-speed driving protection module is the single-row direct insertion structures of 15 pin; it is a kind of special driving chip that typically is applicable to the IGBT that 300A is following; adopt the high-isolating optical coupler as Signal Spacing, have key properties such as single supply, positive back bias voltage, over-current detection, protection, soft shutoff.Working power is independent current source 20 ± 1V, and voltage stabilizing circuit is contained in inside, for the grid of ICBT provides+driving voltage of 15V, provides during shutoff-bias voltage of 5V, makes its reliable turn-off.When pin 15 and pin 14 have the 10mA electric current by the time, pin 3 output high level and make IGBT conducting in 1 μ s; And when pin 15 and pin 14 no currents by the time, pin 3 output low levels are turn-offed IGBT; If withdraw from saturatedly because of bearing short circuit current during the ICBT conducting, Vce rises rapidly, and pin 6 is unsettled, and pin 3 current potentials are just beginning soft shutoff behind about 3.5 μ s after the short circuit.

Yet; there are some shortcomings in traditional EXB841 driver module: at first; EXB841 overcurrent protection threshold values is too high; Vce trigger action during greater than 7V; it is 3V that IGBT collection when normally is penetrated pressure drop, and when Vce=7.5V, IGBT is serious overcurrent; even turn-off IGBT this moment, IGBT is damaged.Simultaneously, because this moment, EXB841 inside did not lock the function of input signal, therefore, overcurrent also can further damage EXB841; Secondly, EXB841 only can provide-the 5V bias voltage when realizing normal turn-off, and is higher at switching frequency, when load is excessive, and turn off process is unreliable; Once more, EXB841 does not have the over current protecting self-locking function, and the cut-off signals that the soft turn off process of its grid voltage may be transfused to when short-circuit protection interrupts.

Existing corrective measure still exists some not enough: 1. some designs can not fundamentally solve above several shortcomings of EXB841 driver module; 2. though some designs can overcome the intrinsic shortcoming of EXB841 driver module to a certain extent preferably, the connection of circuit is too complicated, and the cost of making is too high, causes lacking feasibility in the practical application link, can not well solve practical problem.

The content of utility model

The utility model adopts based on the Drive Protecting Circuit of the EXB841 chip for driving driving protection module as IGBT; not only can control the unlatching of IGBT device and shutoff, realization protection effectively to IGBT device and EXB841 chip for driving; simultaneously; by improvement to driving protection module circuit; also can overcome above-mentioned several shortcomings of EXB841 chip preferably; and circuit design is simple, and is with low cost, is easy to safeguard.

The utility model is realized by following measure:

A kind of IGBT drive circuit of the present utility model; described drive circuit is made up of the driving protection module that the power module that is used to power and being used to drives IGBT; power module comprises the UC3845 chip; drive protection module and comprise the EXB841 chip; described power module is provided with+20V and+dc voltage output end of 12V, the dc voltage output end of described+20V and+12V is connected the voltage input end that drives protection module.

1 pin of above-mentioned EXB841 chip U2 is by electrochemical capacitor C14 ground connection, and 2 pin of EXB841 chip U2 are by electrochemical capacitor C15 ground connection, and 6 pin of EXB841 chip U2 connect the positive pole of diode V9, and the negative pole of diode V9 is connected with the collector electrode of IGBT.

The negative pole of the in-phase input end 15 pin sending and receiving optical diode V8 of above-mentioned EXB841 chip U2, the positive pole of light-emitting diode V8 connects+the 12V voltage input end by resistance R 21.

The drive signal output of above-mentioned EXB841 chip U2 is connected with the grid of IGBT by resistance R 17.

Advantage and the effect that the utlity model has are:

The drive circuit of the utility model design has stronger dynamic driving ability, can provide the driving pulse with edge, precipitous front and back for the IGBT device grids, provides suitable forward grid voltage and reverse grid voltage to the IGBT device simultaneously.Accomplished effective isolation of signal input circuit and signal output loop, the fail safe when having improved the circuit operate as normal.The components and parts speed that adopts is fast, and stability is high, and the input/output signal transmission does not have time-delay, can reach higher application requirements.When fortuitous events such as short circuit, overcurrent occurring; can send guard signal; the controlling and driving protection module is protected IGBT device and interlock circuit; in the protection process; can suppress fault current automatically by reducing grid voltage gradually in the permission time at the IGBT device, realize the soft shutoff of IGBT device.In addition, entire circuit is short and sweet, and components and parts are cheap, is easy to safeguard, very is suitable for practical application area.

Description of drawings

Fig. 1 is an IGBT driving circuit structure block diagram among the utility model embodiment

Fig. 2 is based on the operating circuit schematic diagram of the switch power module of UC3845 among the utility model embodiment

Fig. 3 is based on the operating circuit schematic diagram of the driving protection module of EXB841 among the utility model embodiment

Embodiment

Below in conjunction with accompanying drawing the utility model is described further:

Each module annexation among the utility model embodiment as shown in Figure 1; whole design comprises that EXB841 drives protection module; UC3845 current mode control module and IGBT module; the UC3845 current mode control module provides the two-way power supply for the EXB841 drive circuit module; be respectively+20V and+12V, EXB841 drives protection module and provides drive signal for the IGBT device.Under the normal condition, when EXB841 chip U2 signal input part 14 pin and 15 pin had electric current to flow through, 3 pin of EXB841 chip U2 provided drive signal to the IGBT device, make the IGBT break-over of device; Flow through when control circuit makes EXB841 chip U2 signal input part 14 pin and 15 pin no currents, pin 3 current potentials of EXB841 chip U2 can be dropped rapidly to OV (with respect to EXB841 chip U2 pin 1 low 5V), make IGBT device reliable turn-off.When over-current phenomenon avoidance took place, EXB841 chip U2 stoped the input of input signal, and pin 3 current potentials of EXB841 chip U2 are progressively descended, and slowly turn-offs the IGBT device, realized the protection to IGBT device and EXB841 chip.

Among the utility model embodiment based on the operating circuit of the switch power module of UC3845 as shown in Figure 2, comprise UC3845 chip U1 a slice in the UC3845 control module, voltage-stabiliser tube 7812, triode Q1, Schottky diode V2, diode V1, diode V4, diode V5, diode V6, diode V7, resistance R 1, resistance R 2, resistance R 3, resistance R 4, resistance R 5, resistance R 6, resistance R 7, resistance R 8, resistance R 9, resistance R 10, resistance R 11, resistance R 12, resistance R 13, resistance R 14, resistance R 15, resistance R 16, capacitor C 1, capacitor C 2, capacitor C 3, electrochemical capacitor C4, capacitor C 5, capacitor C 6, electrochemical capacitor C7, capacitor C 8, capacitor C 9, electrochemical capacitor C10, capacitor C 11, electrochemical capacitor C12, electrochemical capacitor C13.Wherein 1 pin of UC3845 chip U1 is connected with an end of resistance R 2, and the other end of resistance R 2 is by resistance R 1 ground connection, and capacitor C 1 is in parallel with resistance R 2; 2 pin of UC3845 chip U1 are by resistance R 1 ground connection; 3 pin of UC3845 chip U1 pass through capacitor C 6 ground connection, the end of while connecting resistance R9, and the other end of resistance R 9 passes through capacitor C 9 ground connection, the end of while connecting resistance R12, the other end of resistance R 12 is by resistance R 14 ground connection; 4 pin of UC3845 chip U1 are by capacitor C 3 ground connection, and are connected by resistance R 3 between 8 pin of UC3845 chip U1; The 5 pin ground connection of UC3845 chip U1; 8 pin of UC3845 chip U1 are by capacitor C 2 ground connection; In the power supply input circuit, input current flows into the loop by diode V1, the end of the negative pole connecting resistance R5 of diode V1, the other end of resistance R 5 is connected with 7 pin of UC3845 chip U1 by R6,4 terminations from the switch transformer T1 are gone into winding simultaneously, the positive pole of the other end 3 terminating diode V4 of winding and the source electrode of triode Q1, the negative pole connecting resistance R13 of diode V4, capacitor C 8 is connected in parallel on resistance R 13 two ends, in addition, the plus earth of Schottky diode V2, negative pole is connected with 7 pin of UC3845 chip U1,7 pin of UC3845 chip U1 are by capacitor C 4 ground connection, and the grid of triode Q1 is connected by 6 pin of resistance R 8 with UC3845 chip U1, and the drain electrode of triode Q1 is by resistance R 14 ground connection; In the feedback loop, 2 ends of feedback winding on switch transformer T1 are connected with the positive pole of diode V7, the negative pole of diode V7 is connected by 2 pin of resistance R 4 with UC3845 chip U1, and the negative pole of diode V7 is by resistance R 16 ground connection, and capacitor C 13 is in parallel with resistance R 16; In the voltage output loop, the positive pole of 8 end diode V6 on the switch transformer T1, the negative pole of diode V6 is+20 volts of voltage output ends, the negative pole of diode V6 is by resistance R 15 ground connection, capacitor C 12 is in parallel with resistance R 15, the positive pole of 6 terminating diode V5 on the switch transformer T1, the negative pole of diode V5 connects 1 pin (electrode input end) of voltage-

stabiliser tube

7812,2 pin ground connection of voltage-

stabiliser tube

7812,3 pin (cathode output end) of voltage-stabiliser tube 7812 are+20 volts of voltage output ends, 1 pin of voltage-stabiliser tube 7812 is connected with 3 pin of voltage-stabiliser tube 7812 by resistance R 11,3 pin of voltage-stabiliser tube 7812 are connected with 2 pin of voltage-stabiliser tube 7812 by

capacitor C

7, and 2 pin of voltage-stabiliser tube 7812 are connected with 1 pin of voltage-stabiliser tube 7812 by capacitor C 10.The voltage output loop provides stable+20 volt and+12 volts of voltages for drive circuit.

As shown in Figure 2, input voltage is via diode V1, the current rectifying and wave filtering circuit that resistance R 5 and resistance R 6 are formed becomes direct voltage, this voltage is through

resistance R

5,4 chargings of 6 pairs of capacitor C of resistance R, the voltage at capacitor C 4 two ends is risen gradually, after 7 pin (VCC end) of UC3845 chip U1 reached turn-on threshold voltage (16V), UC3845 chip U1 started working.The feedback winding both end voltage of switch transformer T1 is after diode V7 and capacitor C 13 rectifying and wave-filterings and resistance R 16, resistance R 1 dividing potential drop, send into the error amplifier inverting input of UC3845 chip U1 from 2 pin, feedback voltage and reference voltage are after error amplifier relatively amplifies, adjust the width of the output pulse of UC3845 chip U1, thus regulated output voltage.

The filter circuit that current feedback loop is made up of current sampling resistor R14 and resistance R 9, resistance R 12, capacitor C 6 and capacitor C 9 is formed.An input of the current comparator of the sampling voltage at resistance R 14 two ends in 3 pin are added to UC3845 chip U1; compare with the error voltage of the other end; when this voltage equaled error voltage (maximum is 1V), the output pulse of UC3845 chip U1 was interrupted, thereby realized current-limiting protection.

This power supply adopts direct drive circuit; the effect of resistance R 8 is peak limiting drive currents; resistance R 2, capacitor C 1 are formed the compensating network of error amplifier; resistance R 3, capacitor C 2 and capacitor C 3 are determined frequency of oscillation and Dead Time, and resistance R 13, capacitor C 8, diode V4 and resistance R 11, capacitor C 7, capacitor C 10, diode V5 and 7812 form surge absorbing circuit with the protection switch pipe.In addition, meet a Schottky diode V2 by resistance R 7, capacitor C 4 and capacitor C 5 between over the ground, be lower than earth potential to prevent output end voltage at 6 pin of UC3845 chip U1.Switching Power Supply is exported at UC3845 chip U1 under the effect of driving pulse, switching tube alternate conduction and shutoff, the secondary alternating voltage that obtains of switch transformer.This voltage can obtain stable VD behind rectifying and wave-filtering.

The operating circuit of driving protection module EXB841 among the utility model embodiment as shown in Figure 3; EXB841 chip for driving and associated external Connection Element module thereof comprise EXB841 chip U2; optical coupler U3 (6N137); electrochemical capacitor C14, electrochemical capacitor C15; diode V9, light-emitting diode V8, light-emitting diode V10; triode Q2, resistance R 18, resistance R 19, resistance R 20, resistance R 21, resistance R 22 and resistance R 23.The negative pole of 15 pin of EXB841 chip U2 (driven in phase signal input part) sending and receiving optical diode V8 wherein, the positive pole of light-emitting diode is connected with+12 volts of direct voltage sources by resistance R 12; 14 pin of EXB841 chip U2 (inverted drive signal input) are connected with the collector electrode (the C utmost point) of triode Q2, the emitter of triode Q2 (the E utmost point) is connected with ground by resistance R 20, input drive signal is connected with the base stage (the B utmost point) of triode Q2 by resistance R 19, the emitter while of triode Q2 is connected with the emitter of the inside triode of optical coupler U3 (6N137), and the collector electrode of the inside triode of optical coupler U3 (6N137) is connected with+12 volts of direct voltage sources by resistance R 22; 10 pin, 11 pin of EXB841 chip U2 are unsettled; The 9 pin ground connection of EXB841 chip U2; 7,8 pin of EXB841 chip U2 are unsettled; 6 pin of EXB841 chip U2 are by resistance R 18 ground connection, and 6 pin (collector voltage test side) connect the positive pole of diode V9 simultaneously, and the negative pole of diode V9 is connected with the collector electrode (the C utmost point) of IGBT device; 5 pin of EXB841 chip U2 (overcurrent protection output) are connected with the light-emitting diode negative pole of the inside of optical coupler U3 (6N137), the positive pole of the light-emitting diode of the inside of optical coupler U3 (6N137) is connected with the negative pole of diode V10, and the positive pole of diode V10 is connected with+20 volts of direct voltage sources by resistance R 23; 4 pin of EXB841 chip U2 are unsettled; 3 pin (drive output) of EXB841 chip U2 are connected with the grid (the G utmost point) of IGBT by resistance R 17; 2 pin of EXB841 chip U2 are connected the minus earth of electrochemical capacitor C15 with the positive pole of electrochemical capacitor C15; 1 pin of EXB841 chip U2 is connected with the positive pole of electrochemical capacitor C14, the minus earth of electrochemical capacitor C14, and 1 pin also is connected with the emitter (the E utmost point) of IGBT device simultaneously.

1 pin of chip for driving EXB841 U2 and 2 pin reach the purpose of filter away high frequency noise respectively by capacity earth; Signal positive input terminal (15 pin of chip for driving EXB841) directly links to each other with power supply through resistance R 21, can effectively improve the conducting electric current of EXB841 input optical coupler like this; In the time of the 3 pin output drive signals of chip for driving EXB841, chip for driving EXB841 detects the voltage (Vce) between collector electrode-emitter of IGBT by fast recovery diode.As Vce during greater than 7V, overcurrent protection Current Control built-in chip type operational amplifier makes it export soft cut-off signals, in 10 μ s the 3 pin output levels of chip for driving EXB841 is reduced to O.For 6 pin that guarantee IGBT EXB841 when overcurrent takes place can in time detect over-current signal; adopt the method for the threshold value that reduces Vce; be connected in series the fast recovery diode of same size again in the fast recovery diode back; number is decided according to the protection threshold value; guarantee when the slight overcurrent of IGBT, can effectively turn-off.

As shown in Figure 3, DRIVER_IN is the external input signal of chip for driving EXB841 chip U2, is the weak electric signal that comes from master control borad; The collector electrode of triode Q2 (the C utmost point) connects the signal negative input end (14 pin) of chip for driving EXB841 chip U2, signal positive input terminal (15 pin) directly links to each other with power supply through current-limiting resistance R21, can effectively improve the conducting electric current of EXB841 chip U2 input optical coupler U3 (6N137) like this, wherein diode V8 is used to indicate input signal.

Under the normal condition; 5 pin of EXB841 chip U2 keep high level; optical coupler U3 (6N137) ends; thereby the inner triode of optical coupler U3 (6N137) is also ended; the inner transistor emitter of optical coupler U3 (6N137) links to each other with the emitter of triode Q2; the emission that makes triode Q2 is low level very; make the input signal of EXB841 chip U2 normally enter inside by R19; finish the IGBT turn on process; wherein optical coupler U3 (6N137) has realized the isolation of strong and weak electricity, has protected the safety of components and parts.

When over-current phenomenon avoidance takes place when; the conducting of optical coupler U3 (6N137) internal body diodes; make the inner triode conducting of optical coupler U3 (6N137); the emitter of triode Q2 becomes high level; stoped the input of triode Q2 base signal, do not had signal flow in EXB841 chip U2 inside, thereby turn-offed the IGBT device; effectively protect the safety of EXB841 and IGBT device, diode V10 is used to indicate the generation of over-current phenomenon avoidance among the figure.After over-current phenomenon avoidance was eliminated, the input signal of EXB841 can be continued to drive the work of IGBT device by automatic unlocking.Q3 among the figure is the IGBT device that is used to realize high-current switch.

Design principle of the present utility model is:

With the UC3845 chip is+20 volts of the switch power module outputs of core and+12 volts direct voltage, offers the driving protection module, and the while also provides voltage source for other parts of circuit.Be in the driving protection module of core with chip for driving EXB841,1 pin of chip for driving EXB841 and 2 pin reach the purpose of filter away high frequency noise respectively by capacity earth; Signal positive input terminal (15 pin of chip for driving EXB841) directly links to each other with power supply through current-limiting resistance, can effectively improve the conducting electric current of EXB841 input optical coupler like this; In the time of the 3 pin output drive signals of chip for driving EXB841, chip for driving EXB841 detects the voltage (Vce) between collector electrode-emitter of IGBT by fast recovery diode.As Vce during greater than 7V, overcurrent protection Current Control built-in chip type operational amplifier makes it export soft cut-off signals, in 10 μ s the 3 pin output levels of chip for driving EXB841 is reduced to O.For 6 pin that guarantee IGBT EXB841 when overcurrent takes place can in time detect over-current signal; adopt the method for the threshold value that reduces Vce; be connected in series the fast recovery diode of same size again in the fast recovery diode back; number is decided according to the protection threshold value; guarantee when the slight overcurrent of IGBT, can effectively turn-off.Under the normal condition, when EXB841 chip signal input 14 pin and 15 pin had electric current to flow through, 3 pin of EXB841 chip provided drive signal to the IGBT device, make the IGBT break-over of device; Flow through when control circuit makes EXB841 chip signal input 14 pin and 15 pin no currents, pin 3 current potentials of EXB841 can be dropped rapidly to OV, make IGBT device reliable turn-off.When over-current phenomenon avoidance takes place when; the EXB841 chip is by the outer protection circuit function; the reverse input end that stops the input EXB841 chip of input signal; there is not signal flow in EXB841 inside; the drive signal output 3 pin current potentials of EXB841 are progressively descended; slowly turn-off the IGBT device, realize protection IGBT device and EXB841 chip.

Claims

1. IGBT drive circuit; it is characterized in that: described drive circuit is made up of the driving protection module that the power module that is used to power and being used to drives IGBT; power module comprises the UC3845 chip; drive protection module and comprise the EXB841 chip; described power module is provided with+20V and+dc voltage output end of 12V, the dc voltage output end of described+20V and+12V is connected the voltage input end that drives protection module.

2. IGBT Drive Protecting Circuit according to claim 1; it is characterized in that: 1 pin of described EXB841 chip U2 is by electrochemical capacitor C14 ground connection; 2 pin of EXB841 chip U2 are by electrochemical capacitor C15 ground connection; 6 pin of EXB841 chip U2 connect the positive pole of diode V9, and the negative pole of diode V9 is connected with the collector electrode of IGBT.

3. a kind of IGBT Drive Protecting Circuit according to claim 1 is characterized in that: the negative pole of the in-phase input end 15 pin sending and receiving optical diode V8 of described EXB841 chip U2, the positive pole of light-emitting diode V8 connects+the 12V voltage input end by resistance R 21.

4. a kind of IGBT Drive Protecting Circuit according to claim 1 is characterized in that: the drive signal output of described EXB841 chip U2 is connected with the grid of IGBT by resistance R 17.