Positive and negative voltage adjustable insulated gate bipolar transistor driving circuit

Abstract

The utility model provides an insulated gate bipolar transistor driving circuit with adjustable positive and negative voltages, comprising a magnetic isolation module, the input end of which is connected with a driving signal and outputs an isolation driving signal; the input end of the first voltage regulating module is connected with the first positive voltage and outputs a second positive voltage within a first preset range; the input end of the second voltage regulating module is connected with the first negative voltage and outputs a second negative voltage within a second preset range; the push-pull output module is connected between the second positive voltage and the second negative voltage, the control end of the push-pull output module is connected with an isolation driving signal, and the output end of the push-pull output module is connected with the gate pole of the to-be-tested insulated gate bipolar transistor through a gate resistor; and the protection module is controllably connected between the output end of the push-pull output module and the second voltage regulation module under the action of the control signal. The driving circuit has the beneficial effects that the positive and negative voltage output capability can be flexibly adjusted according to debugging requirements, the working condition requirements of different clients are met, and the flexibility and adaptability of the driving circuit are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of power electronics, in particular to an insulated gate bipolar transistor drive circuit with adjustable positive and negative voltages. Background Art

[0002] The insulated gate bipolar transistor (IGBT) is a fully controlled, voltage-driven, composite power semiconductor device consisting of a bipolar junction transistor (BJT) and an insulated gate field-effect transistor (MOS). IGBTs, which combine the high input impedance of MOSFETs with the low on-state voltage drop of GTRs, have greatly expanded the application range of semiconductor devices in the power electronics field.

[0003] The IGBT drive circuit is connected between the control circuit and the IGBT to isolate, amplify and protect the drive signal. The drive circuit plays a very important role in the normal operation and protection of the IGBT, and has different degrees of influence on the IGBT's on-state voltage, switching, switching loss, and short-circuit withstand capability. Therefore, the drive circuit design has a significant impact on the dynamic and static performance of the IGBT.

[0004] In practical applications, IGBT driver circuits must meet diverse driving conditions to meet the diverse operating requirements of different customers. However, traditional IGBT driver circuits are often limited to preset fixed parameters and standard application scenarios, making it difficult to fully and flexibly adapt to these diverse requirements. Utility Model Content

[0005] In order to solve the above technical problems, the utility model provides an insulated gate bipolar transistor drive circuit with adjustable positive and negative voltages.

[0006] The technical problem solved by the present invention can be achieved by adopting the following technical solutions:

[0007] An insulated gate bipolar transistor drive circuit with adjustable positive and negative voltages, comprising:

[0008] A magnetic isolation module, wherein an input end of the magnetic isolation module is connected to a drive signal, and an output end of the magnetic isolation module is used to output an isolated drive signal;

[0009] a first voltage regulating module, wherein an input end of the first voltage regulating module is connected to a first positive voltage, and an output end of the first voltage regulating module is used to output a second positive voltage within a first preset range;

[0010] a second voltage regulating module, wherein an input end of the second voltage regulating module is connected to a first negative voltage, and an output end of the second voltage regulating module is used to output a second negative voltage within a second preset range;

[0011] a push-pull output module connected between the second positive voltage and the second negative voltage, wherein a control end of the push-pull output module is connected to the isolated drive signal, and an output end of the push-pull output module is connected to a gate of the insulated gate bipolar transistor to be tested via a gate resistor;

[0012] The protection module is controllably connected between the output end of the push-pull output module and the second voltage regulating module under the action of a control signal.

[0013] Preferably, the magnetic isolation module includes:

[0014] A transformer, wherein the first end of the primary side of the transformer is connected to the ground end, the second end of the primary side of the transformer is connected to the drive signal, the second end of the secondary side of the transformer is connected to the second negative voltage, and the isolated drive signal is output from the first end of the secondary side of the transformer.

[0015] Preferably, the push-pull output module includes:

[0016] a first transistor and a second transistor, wherein the base of the first transistor and the base of the second transistor are both connected to the isolated drive signal, the collector of the first transistor is connected to the second positive voltage, the emitter of the first transistor and the emitter of the second transistor are connected together and connected to the gate resistor, and the collector of the second transistor is connected to the second negative voltage.

[0017] Preferably, the first voltage regulating module includes:

[0018] a first voltage source, configured to provide the first positive voltage;

[0019] a first sliding rheostat, wherein a first end of the first sliding rheostat is connected to the first voltage source via a first resistor, and a second end of the first sliding rheostat is connected to a ground terminal via a second resistor;

[0020] a first voltage-stabilizing source, wherein a first end of the first voltage-stabilizing source is connected to the second end of the first sliding rheostat, and a third end of the first voltage-stabilizing source is connected to the ground end;

[0021] a third transistor, wherein the base of the third transistor is connected to the second end of the first voltage regulator, the emitter of the third transistor is connected to the first end of the first sliding resistor, the collector of the third transistor is connected to the ground end, and the emitter of the third transistor outputs the second positive voltage;

[0022] The third resistor is connected between the base and the emitter of the third transistor.

[0023] Preferably, the second voltage regulating module includes:

[0024] a fourth transistor, wherein a base of the fourth transistor is connected to the first negative voltage via a fourth resistor, a source of the fourth transistor is connected to the first negative voltage, and an emitter of the fourth transistor outputs the second negative voltage;

[0025] a second sliding rheostat, wherein a first end of the second sliding rheostat is connected to the ground end, and a second end of the second sliding rheostat is connected to the emitter of the fourth transistor via a fifth resistor;

[0026] a second voltage-stabilizing source, wherein a first end of the second voltage-stabilizing source is connected to the second end of the second sliding rheostat, a second end of the second voltage-stabilizing source is connected to the ground end, and a third end of the second voltage-stabilizing source is connected to the base of the fourth transistor;

[0027] A switch is controllably connected between the ground terminal and the emitter of the fourth transistor.

[0028] Preferably, the first negative voltage is provided by a second voltage source; or

[0029] The first negative voltage is provided by a level inversion circuit, and the level inversion circuit includes:

[0030] a DC-DC converter, wherein a first terminal of the DC-DC converter is connected to the first positive voltage via a first inductor, a second terminal of the DC-DC converter is connected to a ground terminal, a third terminal of the DC-DC converter is connected to a first voltage-divided signal sampled from the second negative voltage, and a fourth terminal and a fifth terminal of the DC-DC converter are connected to the first positive voltage;

[0031] a first capacitor connected between the first positive voltage and the ground terminal;

[0032] a sixth resistor and a seventh resistor connected in series between the second negative voltage and a ground terminal, and outputting the first voltage-divided signal from a connection point between the sixth resistor and the seventh resistor;

[0033] a second capacitor connected in parallel with the sixth resistor;

[0034] a second inductor, wherein a first end of the second inductor is connected to the first end of the DC-DC converter via a third capacitor, a second end of the second inductor is connected to the ground end via a fourth capacitor, and the second negative voltage is outputted from the second end of the second inductor;

[0035] A first zener diode, wherein an anode of the first zener diode is connected to the first end of the second inductor, and a cathode of the first zener diode is connected to the ground end.

[0036] Preferably, the protection module includes:

[0037] A fifth transistor, wherein the base of the fifth transistor is connected to the control signal, the collector of the fifth transistor is connected to the output end of the push-pull output module, and the emitter of the fifth transistor is connected to the second voltage regulating module.

[0038] Preferably, the control signal is a clamp signal;

[0039] The clamping signal is generated by a clamping circuit, and the clamping circuit includes:

[0040] a sixth transistor, wherein a base of the sixth transistor is connected to the isolation drive signal via a seventh resistor, and an emitter of the sixth transistor outputs the clamping signal;

[0041] a second voltage stabilizing diode, wherein a cathode of the second voltage stabilizing diode is connected to a drain of the insulated gate bipolar transistor to be tested;

[0042] A third diode, wherein the anode of the third diode is connected to the anode of the second voltage stabilizing diode, and the cathode of the third diode is connected to the collector of the sixth transistor.

[0043] Preferably, the control signal is an overcurrent protection signal;

[0044] The overcurrent protection signal is generated by an overcurrent protection circuit, and the overcurrent protection circuit includes:

[0045] a fourth diode, wherein a cathode of the fourth diode is connected to the drain of the insulated gate bipolar transistor to be tested, and an anode of the fourth diode is connected to the first end of the eighth resistor;

[0046] a comparator, wherein a non-inverting input terminal of the comparator is connected to the second end of the eighth resistor, an inverting input terminal of the comparator is connected to a reference signal, and an output terminal of the comparator outputs the overcurrent protection signal;

[0047] The ninth resistor and the tenth resistor are connected in series between the third positive voltage and the ground terminal, and the reference signal is output from the connection point between the ninth resistor and the tenth resistor.

[0048] Preferably, it also includes:

[0049] The RCD buffer circuit is connected in parallel between the source and the drain of the insulated gate bipolar transistor to be tested.

[0050] The advantages or beneficial effects of the technical solution of the utility model are:

[0051] The utility model provides the push-pull output module with an adjustable second positive voltage within a first preset range and a second negative voltage within a second preset range, and can flexibly adjust the positive and negative voltage output capabilities according to debugging requirements to meet the working conditions of different clients, thereby overcoming the limitations of traditional IGBT drive circuits in adapting to diverse driving conditions and significantly improving the flexibility and adaptability of the drive circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 This is a structural block diagram of an IGBT drive circuit in a preferred embodiment of the present invention;

[0053] Figure 2 This is a schematic diagram of an IGBT driving circuit in a preferred embodiment of the present invention;

[0054] Figure 3 FIG. 1 is a schematic diagram of a level inversion circuit in a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0055] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0056] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features therein can be combined with each other.

[0057] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but they are not intended to limit the present invention.

[0058] Example 1

[0059] See also Figure 1 In a preferred embodiment of the present invention, based on the above-mentioned problems existing in the prior art, a positive and negative voltage adjustable insulated gate bipolar transistor (IGBT) drive circuit is provided, comprising:

[0060] A magnetic isolation module 1, wherein the input end of the magnetic isolation module 1 is connected to the driving signal, and the output end of the magnetic isolation module 1 is used to output the isolated driving signal;

[0061] a first voltage regulating module 2, wherein an input end of the first voltage regulating module 2 is connected to a first positive voltage, and an output end of the first voltage regulating module 2 is used to output a second positive voltage within a first preset range;

[0062] a second voltage regulating module 3, wherein an input end of the second voltage regulating module 3 is connected to the first negative voltage, and an output end of the second voltage regulating module 3 is used to output a second negative voltage within a second preset range;

[0063] A push-pull output module 4 is connected between the second positive voltage and the second negative voltage, a control end of the push-pull output module 4 is connected to the isolated drive signal, and an output end of the push-pull output module 4 is connected to the gate (or gate) of the insulated gate bipolar transistor T1 to be tested through a gate resistor Rg;

[0064] The protection module 5 is controllably connected between the output end of the push-pull output module 4 and the second voltage regulating module 3 under the action of the control signal Scontr.

[0065] Specifically, an embodiment of the present invention provides a high-frequency IGBT drive circuit with adjustable gate positive and negative voltages, which consists of a magnetic isolation module 1, a first voltage regulation module 2, a second voltage regulation module 3, a push-pull output module 4 and a protection module 5.

[0066] The driving circuit of this embodiment can be applied to IGBT testing, with the insulated gate bipolar transistor T1 to be tested being the test target.

[0067] Magnetic isolation module 1 is used to isolate and protect the input signal source, i.e., the drive signal, and output an isolated drive signal, i.e., the isolated drive signal. This magnetic isolation technology ensures that the drive signal does not directly affect subsequent circuits, thereby improving circuit reliability and safety.

[0068] The push-pull output module 4 is used to amplify the isolated driving signal and output the amplified signal to the gate of the insulated gate bipolar transistor T1 to be tested through the gate resistor Rg to drive the IGBT and implement the test of the IGBT.

[0069] The first voltage regulating module 2 is used to regulate the input first positive voltage to provide a second positive voltage within a first preset range. The second positive voltage is used to supply positive power to the push-pull output module 4.

[0070] The second voltage regulating module 3 is used to regulate the input first negative voltage to provide a second negative voltage within a second preset range. The second negative voltage is used to supply negative power to the push-pull output module 4.

[0071] The regulated positive and negative voltage values ​​are provided to the push-pull output module 4 through the first voltage regulating module 2 and the second voltage regulating module 3. The push-pull output module 4 operates under the positive and negative voltage power supply and outputs the amplified signal to the gate of the IGBT T1 to be tested through the gate resistor Rg, thereby providing a more stable and efficient IGBT drive signal.

[0072] Furthermore, under the control of the control signal Scontr, the protection module 5 is controllably connected between the output of the push-pull output module 4 and the second voltage regulating module 3. When an abnormality occurs in the circuit, the protection module 5 can quickly cut off the output of the push-pull output module 4 to protect the circuit on the magnetically isolated secondary side from damage.

[0073] In this embodiment, the drive signal is a pulse-width modulated (PWM) signal. A PWM signal is a square wave signal whose duty cycle (i.e., the proportion of the high-level time in the entire cycle) determines the average on-time of the IGBT. By adjusting the duty cycle of the PWM signal, the on-time of the IGBT can be precisely controlled, thereby achieving power control.

[0074] As a preferred embodiment, the magnetic isolation module 1 includes:

[0075] Transformer U1, the first terminal of the primary side of transformer U1 is connected to the ground terminal, the second terminal of the primary side of transformer U1 is connected to the driving signal, the second terminal of the secondary side of transformer U1 is connected to the second negative voltage, and the isolated driving signal is output from the first terminal of the secondary side of transformer U1.

[0076] Specifically, in this embodiment, the magnetic isolation module 1 adopts isolation technology based on chip-level transformers. Unlike the light-emitting diodes (LEDs) and photodiodes used in traditional optocouplers, the magnetic isolation technology uses wafer-level technology to directly manufacture the transformer U1 on the chip, which has higher integration, smaller size and lower power consumption.

[0077] The first end of the primary side of the transformer U1 (usually marked as "pin 1" or "primary-") is directly connected to the ground terminal (GND) to ensure that the reference potential of the signal is consistent; the second end of the primary side (usually marked as "pin 2" or "primary+") is connected to the PWM drive signal input terminal for receiving the PWM signal to be isolated; the first end of the secondary side of the transformer U1 (usually marked as "pin 3" or "secondary output") is used to output the isolated PWM signal, that is, the isolated drive signal; the second end of the secondary side (usually marked as "pin 4" or "secondary-") is connected to the second negative voltage to provide the necessary bias voltage to ensure the normal operation of the secondary circuit.

[0078] The operating principle is as follows: When a PWM drive signal is input to the primary side of transformer U1, a corresponding induced electromotive force is generated on the secondary side through magnetic field coupling. This induced electromotive force, after appropriate circuit processing, is converted into an isolated PWM signal. Due to the high coupling coefficient and low loss characteristics of transformer U1, the isolated PWM signal maintains the same duty cycle and frequency as the input signal, while achieving electrical isolation between circuits.

[0079] Transformer U1 uses magnetic isolation to couple square wave signals, which can provide steep rise and fall speeds, almost no delay transmission, and can more accurately transmit the duty cycle and frequency information of the PWM signal, making it suitable for high-frequency and high-power power modules such as IGBT, MOSFET, etc.

[0080] As a preferred embodiment, the push-pull output module 4 includes:

[0081] The first transistor Q1 and the second transistor Q2, the base of the first transistor Q1 and the base of the second transistor Q2 are both connected to the isolation drive signal, the collector of the first transistor Q1 is connected to the second positive voltage, the emitter of the first transistor Q1 and the emitter of the second transistor Q2 are connected together and connected to the gate resistor Rg, and the collector of the second transistor Q2 is connected to the second negative voltage.

[0082] Specifically, in this embodiment, the push-pull output module 4 is composed of two transistors, namely a first transistor Q1 and a second transistor Q2, for increasing the outgoing current capacity and realizing the control of the IGBT.

[0083] In this embodiment, a PWM signal is provided by an external signal source, isolated by a magnetic isolation module, and then input into a push-pull output module. The push-pull output module controls the conduction and cutoff of the first and second transistors Q1 and Q2 based on the high and low level changes of the PWM signal, thereby turning the IGBT on and off.

[0084] When the PWM signal is high, transistor Q1 turns on. The second positive voltage flows through the collector-emitter path of transistor Q1 and is applied to the gate of the IGBT under test via gate resistor Rg, turning the IGBT on. Simultaneously, because the base of transistor Q2 is also high, but its collector is connected to a negative voltage, transistor Q2 remains off and does not participate in the current flow.

[0085] When the PWM signal is at a low level, the first transistor Q1 is turned off and the second transistor Q2 is turned on. Since the collector of the second transistor Q2 is connected to the second negative voltage, the emitter signal of the second transistor Q2 is applied to the gate of the IGBT through the gate resistor Rg, turning off the IGBT.

[0086] By continuously changing the duty cycle of the PWM signal, the IGBT on-time can be adjusted and controlled.

[0087] In this embodiment, the gate resistor Rg is used to limit the peak value of the IGBT gate current, protecting the IGBT from the impact of excessive gate drive current. At the same time, it also helps to stabilize the switching process of the IGBT and reduce switching losses and electromagnetic interference.

[0088] As a preferred embodiment, the first voltage regulating module 2 includes:

[0089] A first voltage source, configured to provide a first positive voltage;

[0090] A first sliding resistor RS1, wherein a first end of the first sliding resistor RS1 is connected to a first voltage source via a first resistor R1, and a second end of the first sliding resistor RS1 is connected to a ground terminal via a second resistor R2;

[0091] a first voltage stabilizing source U2, wherein a first end of the first voltage stabilizing source U2 is connected to the second end of the first sliding resistor RS1, and a third end of the first voltage stabilizing source U2 is connected to the ground end;

[0092] a third transistor Q3, wherein the base of the third transistor Q3 is connected to the second end of the first voltage regulator U2, the emitter of the third transistor Q3 is connected to the first end of the first sliding resistor RS1, the collector of the third transistor Q3 is connected to the ground end, and a second positive voltage is output from the emitter of the third transistor Q3;

[0093] The third resistor R3 is connected between the base and the emitter of the third transistor Q3.

[0094] Specifically, the first voltage regulating module 2 is a positive voltage adjustable power supply, which is composed of a first sliding rheostat RS1, a first resistor R1, a second resistor R2, a third resistor R3, a first voltage stabilizing source U2 and a third transistor Q3 to achieve voltage regulation and stable output.

[0095] In this embodiment, the first positive voltage is +30 V. The first positive voltage is provided by a first voltage source, that is, the first voltage source is a +30 V voltage source, which provides a +30 V DC voltage as the initial input voltage of the first voltage regulating module 2 .

[0096] The first sliding rheostat RS1 is used to adjust the input voltage. Its first end is connected to the first voltage source through the first resistor R1, and its second end is grounded through the second resistor R2. The position of the sliding contact of the sliding rheostat determines the output voltage of the voltage divider circuit.

[0097] The first resistor R1, the second resistor R2 and the sliding rheostat RS1 together form a voltage divider circuit for preliminary voltage regulation.

[0098] The preferred voltage regulator, U2, is a TL431. Its first terminal (reference terminal) is connected to the second terminal of the sliding rheostat RS1, and its third terminal is grounded. The TL431 uses an internal feedback mechanism to ensure a stable voltage output at its second terminal (cathode). This voltage is determined by the reference terminal voltage and an internal reference voltage (typically 2.5V).

[0099] The third transistor Q3 functions as a voltage follower or amplifier. Its base is connected to the second terminal of TL431, its emitter is connected to the first terminal of the sliding rheostat RS1 (which is also the other terminal of the first resistor R1), and its collector is grounded. Adjusting the output voltage of TL431 controls the on / off state of the third transistor Q3. When the base is high, the third transistor Q3 is off; when the base is low, the third transistor Q3 is on, and a second positive voltage is output from the emitter of the third transistor Q3.

[0100] By adjusting the position of the sliding contact of the first sliding resistor RS1, the value of the second positive voltage output from the emitter is adjusted.

[0101] In this embodiment, the first preset range is 15V to 22V. The first voltage regulating module 2 is intended to regulate the input +30V first positive voltage to a second positive voltage within the range of 15V to 22V through the first sliding rheostat RS1.

[0102] The third resistor R3 serves as a base bias resistor, is connected between the base and emitter of the third transistor Q3, and is used to stabilize the operating point of the third transistor Q3 to prevent oscillation.

[0103] The operating principle is as follows: When the sliding contact position of the first sliding rheostat RS1 changes, the output voltage of the voltage divider circuit changes accordingly, and this voltage serves as the reference voltage for the TL431. The TL431 adjusts its cathode output voltage based on the difference between its internal reference voltage (2.5V) and the external reference voltage to maintain a constant voltage difference between the two. The base voltage of the third transistor Q3 changes with the TL431 cathode voltage, thereby controlling Q3's collector-emitter current and outputting a second positive voltage from the emitter.

[0104] As a preferred embodiment, the second voltage regulating module 3 includes:

[0105] a fourth transistor Q4 , wherein a base of the fourth transistor Q4 is connected to the first negative voltage via a fourth resistor R4 , a source of the fourth transistor Q4 is connected to the first negative voltage, and an emitter of the fourth transistor Q4 outputs a second negative voltage;

[0106] a second sliding resistor RS2, wherein a first end of the second sliding resistor RS2 is connected to the ground end, and a second end of the second sliding resistor RS2 is connected to the emitter of the fourth transistor Q4 via a fifth resistor R5;

[0107] The second voltage stabilizing source U3, the first end of the second voltage stabilizing source U3 is connected to the second end of the second sliding resistor RS2, the second end of the second voltage stabilizing source U3 is connected to the ground end, and the third end of the second voltage stabilizing source U3 is connected to the base of the fourth transistor Q4.

[0108] Specifically, the second voltage regulating module 3 serves as a negative voltage adjustable power supply, and is composed of a second sliding rheostat RS2 , a second voltage stabilizing source U3 , a fourth transistor Q4 , a fourth resistor R4 , and a fifth resistor R5 .

[0109] In this embodiment, the first negative voltage is -20V.

[0110] As a preferred embodiment, the first negative voltage is provided by a second voltage source, that is, the second voltage source is a -20V voltage source, which provides a -20V DC voltage as the initial input voltage of the second voltage regulating module 3 .

[0111] The first end of the second sliding rheostat RS2 is connected to ground, providing a reference point for voltage adjustment. The first end of the second voltage-stabilizing source U3 is connected to the second end of the second sliding rheostat RS2, and together with the fifth resistor R5, they form a voltage divider circuit. The third end of the second voltage-stabilizing source U3 is connected to the base of the fourth transistor Q4. A feedback mechanism is used to stabilize the output voltage and control the on and off state of the fourth transistor Q4. When the base is at a high level, the fourth transistor Q4 is off; when the base is at a low level, the fourth transistor Q4 is on, outputting a second negative voltage from the emitter of the fourth transistor Q4.

[0112] In this embodiment, the second preset range is -5V to -18V.

[0113] By adjusting the resistance of the sliding rheostat, the voltage of the emitter of the fourth transistor Q4 can be changed, thereby outputting a second negative voltage in the range of -5V to -18V.

[0114] As a preferred embodiment, the second voltage regulating module 3 further includes:

[0115] The switch SW1 is controllably connected between the ground terminal and the emitter of the fourth transistor Q4.

[0116] Specifically, when a negative voltage of 0V is required to be output, the switch SW1 is closed, the emitter of the fourth transistor Q4 is directly grounded, and the fourth transistor Q4 is controlled to be turned off, thereby disconnecting the input of the -20V voltage. At this time, the output voltage of the second voltage regulating module 3 is 0V.

[0117] As a preferred embodiment, the protection module 5 includes:

[0118] The fifth transistor Q5 has a base connected to the control signal Scontr, a collector connected to the output end of the push-pull output module 4 , and an emitter connected to the second voltage regulating module 3 .

[0119] Specifically, when the control signal Scontr is at a low level, the fifth transistor Q5 is turned off, and the connection between the push-pull output module 4 and the second voltage regulating module 3 is disconnected.

[0120] When the control signal Scontr is at a high level, the fifth transistor Q5 is turned on, and a path is formed between the collector and emitter of the fifth transistor Q5 to lower the output voltage of the push-pull output module 4, thereby protecting the IGBT.

[0121] In this embodiment, the control signal Scontr is generated by real-time detection of the working state of the IGBT and based on the output signal of the drive circuit (i.e., the signal at point P). Once the IGBT is damaged or abnormal, the signal at point P will change accordingly, triggering the corresponding adjustment of the control signal Scontr, thereby quickly cutting off or adjusting the secondary side circuit connected to the IGBT, ensuring that the secondary side circuit will not suffer further damage due to the damage of the IGBT, thereby reducing the risk of damage to the IGBT.

[0122] As a preferred embodiment, the control signal Scontr is a clamp signal;

[0123] The clamping signal is generated by the clamping circuit 6 .

[0124] Specifically, a first end of the clamp circuit 6 is connected to the output end of the driving circuit, ie, the drain (or collector) of the IGBT to be tested, and a second end is connected to the isolated driving signal.

[0125] Collector clamping technology is used to prevent IGBT from being damaged by short circuit.

[0126] As a preferred embodiment, the clamping circuit 6 includes:

[0127] a sixth transistor Q6 , wherein a base of the sixth transistor Q6 is connected to the isolation driving signal via a seventh resistor R7 , and a clamping signal is output from an emitter of the sixth transistor Q6 ;

[0128] a second voltage stabilizing diode D2, wherein the cathode of the second voltage stabilizing diode D2 is connected to the drain of the insulated gate bipolar transistor T1 to be tested;

[0129] The third diode D3 has an anode connected to the anode of the second voltage stabilizing diode D2 and a cathode connected to the collector of the sixth transistor Q6.

[0130] Specifically, the clamping circuit 6 is composed of a sixth transistor Q6 , a second voltage stabilizing diode D2 and a third diode D3 .

[0131] The base of the sixth transistor Q6 receives the isolated driving signal via the seventh resistor R7, so that the sixth transistor Q6 can be turned on or off in response to changes in the driving signal.

[0132] When the driving signal is at a high level, the sixth transistor Q6 is turned on.

[0133] When the driving signal is at a low level, the sixth transistor Q6 is turned off.

[0134] The function of the second zener diode D2 is to set a voltage threshold. When the drain voltage of the insulated gate bipolar transistor T1 to be tested exceeds the threshold, the second zener diode D2 will start to conduct, thereby triggering the clamping mechanism.

[0135] Specifically, when the drive signal is high, the IGBT turns on. If the output signal of the IGBT drive circuit (the signal at point P) exceeds the voltage regulation value of the second Zener diode D2, the sixth transistor Q6 is also in the on state at this time. Due to the conduction of the second Zener diode D2 and the third diode D3, the emitter of the sixth transistor Q6 will output a clamping signal, triggering the conduction of the fifth transistor Q5, thereby shutting off the gate of the insulated gate bipolar transistor T1 under test, thus realizing the protection circuit function.

[0136] On the contrary, if the IGBT works normally, the signal at point P does not exceed the voltage regulation value of the second voltage regulator diode D2, the second voltage regulator diode D2 is turned off, and the fifth transistor Q5 is also turned off.

[0137] The sixth transistor Q6 controls the clamp and only works when the PWM signal is turned on.

[0138] As a preferred embodiment, the control signal Scontr is an overcurrent protection signal;

[0139] The overcurrent protection signal is generated by the overcurrent protection circuit 7 .

[0140] Specifically, in this embodiment, by setting an overcurrent protection circuit 7, the output signal of point P is compared with a preset reference signal, so as to output an overcurrent protection signal in the event of a short circuit, triggering the fifth transistor Q5 to turn on, and then turning off the gate of the insulated gate bipolar transistor T1 to be tested, thereby preventing further damage to the IGBT and achieving overcurrent protection.

[0141] As a preferred embodiment, the overcurrent protection circuit 7 includes:

[0142] a fourth diode D4 , wherein a cathode of the fourth diode D4 is connected to the drain of the insulated gate bipolar transistor T1 to be tested, and an anode of the fourth diode D4 is connected to the first end of the eighth resistor R8 ;

[0143] The comparator U5 has a non-inverting input terminal connected to the second end of the eighth resistor R8, an inverting input terminal connected to the reference signal, and an overcurrent protection signal is output from an output terminal of the comparator U5.

[0144] Specifically, when the IGBT operates normally and the output signal at point P does not exceed the reference signal, the output terminal of the comparator U5 maintains a low level and the fifth transistor Q5 is also turned off.

[0145] Once a short circuit or overcurrent occurs in the IGBT, the signal at point P will rise rapidly and exceed the reference signal. At this time, the comparator U5 flips and outputs a high-level overcurrent protection signal, triggering the fifth transistor Q5 to turn on, so as to quickly turn off the gate voltage of the IGBT, prevent further damage to the IGBT, and achieve overcurrent protection.

[0146] Considering the fluctuation of the IGBT when it is turned off, a negative voltage is used in this embodiment to ensure reliable gate turn-off. Therefore, by turning on the fifth transistor Q5, the gate voltage is pulled down to the second negative voltage, thereby effectively achieving overcurrent protection for the IGBT.

[0147] In this embodiment, the fourth diode D4 is a fast recovery diode.

[0148] In this embodiment, in order to enhance the sensitivity and stability of current detection, the fourth diode D4 is not a single diode, but a series of diodes is used to cope with possible current shocks.

[0149] As a preferred embodiment, the ninth resistor R9 and the tenth resistor R10 are connected in series between the third positive voltage and the ground terminal, and the reference signal is output from the connection point between the ninth resistor R9 and the tenth resistor R10.

[0150] In this embodiment, the third positive voltage is +15 V. The ninth resistor R9 and the tenth resistor R10 are connected in series to divide the voltage and generate a reference signal as a threshold value for overcurrent protection.

[0151] Furthermore, by adjusting the resistance values ​​of the ninth resistor R9 and the tenth resistor R10, the threshold of the overcurrent protection can be flexibly set.

[0152] As a preferred embodiment, the present invention further comprises:

[0153] The RCD snubber circuit 8 is connected in parallel between the source and the drain of the insulated gate bipolar transistor T1 to be tested.

[0154] Specifically, in this embodiment, an RCD snubber circuit 8 is provided between the source and drain of the insulated gate bipolar transistor T1 to be tested, so as to reduce the load of the active switch (i.e., IGBT) during high-frequency switching operations, thereby reducing energy loss during the switching process and improving the efficiency and reliability of the circuit.

[0155] Furthermore, the RCD snubber circuit 8 includes a fifth diode D5, a fifth capacitor C5, and an eleventh resistor R11. The anode of the fifth diode D5 is connected to the drain of the insulated gate bipolar transistor T1 under test; the fifth capacitor C5 and the eleventh resistor R11 are connected in parallel between the cathode of the fifth diode D5 and the source of the insulated gate bipolar transistor T1 under test.

[0156] During the switching operation, the RCD snubber circuit 8 can absorb and release the transient voltage and current fluctuations generated by the IGBT, thereby protecting the IGBT from damage caused by overvoltage and overcurrent, and playing a certain role in alleviating overvoltage and suppressing bus voltage oscillations.

[0157] Furthermore, the system further includes: a twelfth resistor R12 and a sixth capacitor C6 connected in parallel between the output terminal of the push-pull output module 4 and the second negative voltage.

[0158] Specifically, the twelfth resistor R12 and the sixth capacitor C6 form a filter circuit to filter out high-frequency noise in the IGBT gate signal, thereby further enhancing the anti-interference capability and stability of the circuit.

[0159] Furthermore, the system further includes a bidirectional voltage regulator D6 , wherein a first end of the bidirectional voltage regulator D6 is connected to the gate of the insulated gate bipolar transistor T1 to be tested, and a second end of the bidirectional voltage regulator D6 is connected to a second negative voltage.

[0160] Specifically, when the IGBT gate voltage is too high, the bidirectional voltage regulator D6 is turned on to provide stable voltage protection and prevent the IGBT from being damaged due to abnormal voltage.

[0161] Furthermore, in order to further optimize the switching performance of the IGBT, the embodiment of the present invention can also replace the gate resistor Rg with a circuit with a diode added in parallel to form a turn-on resistor and a turn-off resistor.

[0162] Example 2

[0163] In a preferred embodiment of the present invention, the first negative voltage may be -30V.

[0164] It is worth noting that such a high negative pressure value may not be required in actual applications.

[0165] This embodiment is implemented by Figure 2 The level inversion circuit shown converts the first positive voltage of 30V into a first negative voltage of -30V, thereby providing the required negative voltage source for the second voltage regulating module 3 and reducing the need for additional voltage source settings.

[0166] As a preferred embodiment, the first negative voltage is provided by a level inversion circuit, and the level inversion circuit includes:

[0167] A DC-DC converter U4, wherein a first terminal of the DC-DC converter U4 is connected to a first positive voltage via a first inductor L1, a second terminal of the DC-DC converter U4 is connected to a ground terminal, a third terminal of the DC-DC converter U4 is connected to a first voltage-divided signal sampled from a second negative voltage (the signal is obtained by voltage-dividing a sixth resistor R6 and a seventh resistor R7 connected in series), and a fourth terminal and a fifth terminal of the DC-DC converter U4 are connected to the first positive voltage;

[0168] A first capacitor C1 is connected between the first positive voltage and the ground terminal, and is used to smooth the DC voltage and reduce voltage fluctuations;

[0169] A sixth resistor R6 and a seventh resistor R7 are connected in series between the second negative voltage and the ground terminal, and a first voltage-divided signal is output from the connection point between the sixth resistor R6 and the seventh resistor R7; the first voltage-divided signal is generated by voltage division, and the signal is used for feedback control of the DC-DC converter;

[0170] A second capacitor C2 is connected in parallel with the sixth resistor R6 to further stabilize the voltage-divided signal;

[0171] a second inductor L2, wherein a first end of the second inductor L2 is connected to a first end of the DC-DC converter via a third capacitor C3, and a second end of the second inductor L2 is connected to a ground terminal via a fourth capacitor C4. A second negative voltage is output from the second end of the second inductor L2. The second inductor L2 is used to smooth the output voltage and reduce ripple;

[0172] The first zener diode D1 has an anode connected to the first end of the second inductor L2 and a cathode connected to the ground, and is used to protect the circuit from damage caused by transient overvoltage.

[0173] Furthermore, the DC-DC converter U4 is preferably selected as LT1611.

[0174] In this embodiment, the inductance of the first inductor L1 is preferably 22 μH.

[0175] In this embodiment, the inductance of the second inductor L2 is preferably 22 μH.

[0176] The IGBT drive circuit of the utility model can be applied to experimental tests of half-bridge topology. The positive and negative voltages of the drive can be adjusted to meet the various actual drive voltage requirements of different customers and improve the convenience of laboratory debugging.

[0177] The advantages or beneficial effects of adopting the above technical solution are: the utility model provides the push-pull output module with an adjustable second positive voltage within a first preset range and a second negative voltage within a second preset range, and can flexibly adjust the positive and negative voltage output capabilities according to debugging requirements to meet the working conditions of different clients, thereby overcoming the limitations of traditional IGBT drive circuits in adapting to diverse driving conditions and significantly improving the flexibility and adaptability of the drive circuit.

[0178] The above are only preferred embodiments of the present invention and do not limit the implementation methods and protection scope of the present invention. Those skilled in the art should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the contents of this specification and illustrations should be included in the protection scope of the present invention.

Claims

1. An insulated gate bipolar transistor drive circuit with adjustable positive and negative voltages, characterized in that: include: A magnetic isolation module, wherein an input end of the magnetic isolation module is connected to a drive signal, and an output end of the magnetic isolation module is used to output an isolated drive signal; a first voltage regulating module, wherein an input end of the first voltage regulating module is connected to a first positive voltage, and an output end of the first voltage regulating module is used to output a second positive voltage within a first preset range; a second voltage regulating module, wherein an input end of the second voltage regulating module is connected to a first negative voltage, and an output end of the second voltage regulating module is used to output a second negative voltage within a second preset range; a push-pull output module connected between the second positive voltage and the second negative voltage, wherein a control end of the push-pull output module is connected to the isolated drive signal, and an output end of the push-pull output module is connected to a gate of the insulated gate bipolar transistor to be tested via a gate resistor; The protection module is controllably connected between the output end of the push-pull output module and the second voltage regulating module under the action of a control signal.

2. The positive and negative voltage adjustable insulated gate bipolar transistor driving circuit according to claim 1, characterized in that: The magnetic isolation module includes: A transformer, wherein the first end of the primary side of the transformer is connected to the ground end, the second end of the primary side of the transformer is connected to the drive signal, the second end of the secondary side of the transformer is connected to the second negative voltage, and the isolated drive signal is output from the first end of the secondary side of the transformer.

3. The positive and negative voltage adjustable insulated gate bipolar transistor driving circuit according to claim 1, characterized in that: The push-pull output module includes: a first transistor and a second transistor, wherein the base of the first transistor and the base of the second transistor are both connected to the isolated drive signal, the collector of the first transistor is connected to the second positive voltage, the emitter of the first transistor and the emitter of the second transistor are connected together and connected to the gate resistor, and the collector of the second transistor is connected to the second negative voltage.

4. The positive and negative voltage adjustable insulated gate bipolar transistor driving circuit according to claim 1, characterized in that: The first voltage regulating module includes: a first voltage source, configured to provide the first positive voltage; a first sliding rheostat, wherein a first end of the first sliding rheostat is connected to the first voltage source via a first resistor, and a second end of the first sliding rheostat is connected to a ground terminal via a second resistor; a first voltage-stabilizing source, wherein a first end of the first voltage-stabilizing source is connected to the second end of the first sliding rheostat, and a third end of the first voltage-stabilizing source is connected to the ground end; a third transistor, wherein the base of the third transistor is connected to the second end of the first voltage regulator, the emitter of the third transistor is connected to the first end of the first sliding resistor, the collector of the third transistor is connected to the ground end, and the emitter of the third transistor outputs the second positive voltage; The third resistor is connected between the base and the emitter of the third transistor.

5. The positive and negative voltage adjustable insulated gate bipolar transistor driving circuit according to claim 1, characterized in that: The second voltage regulating module includes: a fourth transistor, wherein a base of the fourth transistor is connected to the first negative voltage via a fourth resistor, a source of the fourth transistor is connected to the first negative voltage, and an emitter of the fourth transistor outputs the second negative voltage; a second sliding rheostat, wherein a first end of the second sliding rheostat is connected to the ground end, and a second end of the second sliding rheostat is connected to the emitter of the fourth transistor via a fifth resistor; a second voltage-stabilizing source, wherein a first end of the second voltage-stabilizing source is connected to the second end of the second sliding rheostat, a second end of the second voltage-stabilizing source is connected to the ground end, and a third end of the second voltage-stabilizing source is connected to the base of the fourth transistor; A switch is controllably connected between the ground terminal and the emitter of the fourth transistor.

6. The positive and negative voltage adjustable insulated gate bipolar transistor driving circuit according to claim 1, characterized in that: The first negative voltage is provided by a second voltage source; or The first negative voltage is provided by a level inversion circuit, and the level inversion circuit includes: a DC-DC converter, wherein a first terminal of the DC-DC converter is connected to the first positive voltage via a first inductor, a second terminal of the DC-DC converter is connected to a ground terminal, a third terminal of the DC-DC converter is connected to a first voltage-divided signal sampled from the second negative voltage, and a fourth terminal and a fifth terminal of the DC-DC converter are connected to the first positive voltage; a first capacitor connected between the first positive voltage and the ground terminal; a sixth resistor and a seventh resistor connected in series between the second negative voltage and a ground terminal, and outputting the first voltage-divided signal from a connection point between the sixth resistor and the seventh resistor; a second capacitor connected in parallel with the sixth resistor; a second inductor, wherein a first end of the second inductor is connected to the first end of the DC-DC converter via a third capacitor, a second end of the second inductor is connected to the ground end via a fourth capacitor, and the second negative voltage is outputted from the second end of the second inductor; A first zener diode, wherein an anode of the first zener diode is connected to the first end of the second inductor, and a cathode of the first zener diode is connected to the ground end.

7. The insulated gate bipolar transistor driving circuit with adjustable positive and negative voltages according to claim 1, characterized in that: The protection module includes: A fifth transistor, wherein the base of the fifth transistor is connected to the control signal, the collector of the fifth transistor is connected to the output end of the push-pull output module, and the emitter of the fifth transistor is connected to the second voltage regulating module.

8. The insulated gate bipolar transistor driving circuit with adjustable positive and negative voltages according to claim 1, characterized in that: The control signal is a clamp signal; The clamping signal is generated by a clamping circuit, and the clamping circuit includes: a sixth transistor, wherein a base of the sixth transistor is connected to the isolation drive signal via a seventh resistor, and an emitter of the sixth transistor outputs the clamping signal; a second voltage stabilizing diode, wherein a cathode of the second voltage stabilizing diode is connected to a drain of the insulated gate bipolar transistor to be tested; A third diode, wherein the anode of the third diode is connected to the anode of the second voltage stabilizing diode, and the cathode of the third diode is connected to the collector of the sixth transistor.

9. The positive and negative voltage adjustable insulated gate bipolar transistor driving circuit according to claim 1, characterized in that: The control signal is an overcurrent protection signal; The overcurrent protection signal is generated by an overcurrent protection circuit, and the overcurrent protection circuit includes: a fourth diode, wherein a cathode of the fourth diode is connected to the drain of the insulated gate bipolar transistor to be tested, and an anode of the fourth diode is connected to the first end of the eighth resistor; a comparator, wherein a non-inverting input terminal of the comparator is connected to the second end of the eighth resistor, an inverting input terminal of the comparator is connected to a reference signal, and an output terminal of the comparator outputs the overcurrent protection signal; The ninth resistor and the tenth resistor are connected in series between the third positive voltage and the ground terminal, and the reference signal is output from the connection point between the ninth resistor and the tenth resistor.

10. The insulated gate bipolar transistor driving circuit with adjustable positive and negative voltages according to claim 1, characterized in that: Also includes: The RCD buffer circuit is connected in parallel between the source and the drain of the insulated gate bipolar transistor to be tested.

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