A driving device and a switching power supply

Abstract

A driving device and a switching power supply are disclosed to enable safe turn-off of a switching transistor. The driving device includes a drive push-pull circuit and a clamping circuit. The input terminal of the drive push-pull circuit receives a drive signal, and its output terminal is connected to the gate of the IGBT. The first terminal of the clamping circuit is connected to the gate of the IGBT or the input terminal of the drive push-pull circuit, and the second terminal is connected to the main power terminal of the IGBT's emitter. When the current changes rapidly during the IGBT turn-off process, causing an induced voltage in the stray inductance inside the IGBT, the emitter voltage potential of the IGBT rises. The clamping circuit directly raises the gate voltage of the IGBT or raises the gate voltage of the IGBT by adjusting the input voltage of the drive push-pull circuit. This slows down the turn-off speed of the IGBT and the rate of change of current in the circuit, preventing the peak voltage amplitude of the IGBT from rising to the breakdown voltage and ensuring safe turn-off of the IGBT.

Description

Technical Field

[0001] This application relates to the field of power supply technology, and in particular to a drive device and a switching power supply. Background Technology

[0002] Insulated-gate bipolar transistors (IGBTs) have advantages such as high input impedance, low on-state voltage drop, and high current density, and are widely used in switching power supplies and other devices. When the IGBT turns off and cuts off a large current, the rapid drop in current at the main power port will generate a high-amplitude voltage spike on the stray inductance inside the IGBT. This voltage spike, superimposed on the IGBT, can easily cause overvoltage breakdown, leading to IGBT failure and affecting the normal operation of the equipment. Utility Model Content

[0003] This application provides a driving device and a switching power supply, which can realize the safe shutdown of the switching transistor and improve the working reliability of the switching transistor.

[0004] In a first aspect, embodiments of this application provide a driving device connected to the gate of an IGBT and also capable of being connected to other external control devices. The driving device can drive the IGBT to turn on and off according to a driving signal of a corresponding level sent by the control device. The driving device may include a drive push-pull circuit and a clamping circuit.

[0005] The input terminal of the drive push-pull circuit is used to receive drive signals, and the output terminal of the drive push-pull circuit is connected to the gate of the IGBT. The first terminal of the clamping circuit is connected to the gate of the IGBT or the input terminal of the drive push-pull circuit, and the second terminal of the clamping circuit is connected to the emitter main power terminal of the IGBT. The clamping circuit is used to increase the gate voltage of the IGBT when the voltage difference between the gate and the emitter main power terminal of the IGBT is greater than a preset threshold or the voltage difference between the emitter main power terminal of the IGBT and the input terminal of the drive push-pull circuit is greater than the preset threshold.

[0006] Using the above driving architecture, the clamping circuit is connected between the gate and the main power terminal of the IGBT, or between the input of the push-pull driving circuit and the main power terminal of the IGBT. When a rapid change in current causes the stray inductance inside the IGBT to generate an induced voltage, the emitter voltage potential of the IGBT rises, resulting in an increase in the voltage difference between the gate and the main power terminal of the IGBT, or an increase in the voltage difference between the input of the push-pull driving circuit and the main power terminal of the IGBT. The clamping circuit starts by directly raising the gate voltage of the IGBT or by adjusting the amplitude of the driving signal at the input of the push-pull driving circuit to raise the gate voltage of the IGBT, slowing down the turn-off speed of the IGBT, thereby reducing the rate of current change on the line, preventing the induced voltage generated by the stray inductance from rising further to the breakdown voltage of the IGBT, ensuring the safe turn-off of the IGBT, and allowing the device containing the IGBT to operate normally.

[0007] In one possible design, the clamping circuit includes a bidirectional transient voltage suppressor. With this design, during IGBT turn-off, the rapid drop in current induces a voltage on the stray inductance at the IGBT emitter side. When the amplitude of this induced voltage exceeds the breakdown voltage of the bidirectional transient voltage suppressor, the suppressor either breaks down directly to raise the IGBT gate voltage or raises the gate voltage by adjusting the amplitude of the drive signal received by the push-pull drive circuit. This slows down the IGBT turn-off speed, suppresses the rate of change of current on the line, and prevents the induced voltage generated by the stray inductance from further rising to the IGBT breakdown voltage.

[0008] In one possible design, the clamping circuit includes: a first unidirectional transient voltage suppressor and a second unidirectional transient voltage suppressor.

[0009] The cathode of the first unidirectional transient voltage suppressor is connected to the gate of the IGBT or the input terminal of the drive push-pull circuit; the anode of the first unidirectional transient voltage suppressor is connected to the anode of the second unidirectional transient voltage suppressor; and the cathode of the second unidirectional transient voltage suppressor is connected to the emitter main power terminal of the IGBT.

[0010] In one possible design, the clamping circuit includes a third unidirectional transient voltage suppressor and a fourth unidirectional transient voltage suppressor.

[0011] The anode of the third unidirectional transient voltage suppressor is connected to the gate of the IGBT or the input terminal of the drive push-pull circuit; the cathode of the third unidirectional transient voltage suppressor is connected to the cathode of the fourth unidirectional transient voltage suppressor; and the anode of the fourth unidirectional transient voltage suppressor is connected to the emitter main power terminal of the IGBT.

[0012] In one possible design, the clamping circuit includes a fifth unidirectional transient voltage suppressor and a first diode.

[0013] The anode of the fifth unidirectional transient voltage suppressor is connected to the gate of the IGBT or the input terminal of the drive push-pull circuit, and the cathode of the fifth unidirectional transient voltage suppressor is connected to the cathode of the first diode; the anode of the first diode is connected to the emitter main power terminal of the IGBT.

[0014] In one possible design, the clamping circuit includes a sixth unidirectional transient voltage suppressor and a second diode.

[0015] The cathode of the sixth unidirectional transient voltage suppressor is connected to the emitter main power terminal of the IGBT, and the anode of the sixth unidirectional transient voltage suppressor is connected to the anode of the second diode; the cathode of the second diode is connected to the gate of the IGBT or the input terminal of the drive push-pull circuit.

[0016] In one possible design, the clamping circuit includes a first Zener diode and a third diode.

[0017] The anode of the first Zener diode is connected to the gate of the IGBT or the input terminal of the drive push-pull circuit, and the cathode of the first Zener diode is connected to the cathode of the third diode; the anode of the third diode is connected to the emitter main power terminal of the IGBT.

[0018] By adopting the above design, by selecting a suitable type of Zener diode, the Zener diode can break down and raise the gate voltage of the IGBT before the induced voltage generated by stray inductance rises to the breakdown voltage of the IGBT, thereby slowing down the rate of current change in the circuit and ensuring the safe turn-off of the IGBT.

[0019] In one possible design, the clamping circuit includes a second Zener diode and a fourth diode.

[0020] The cathode of the second Zener diode is connected to the emitter main power terminal of the IGBT, and the anode of the second Zener diode is connected to the anode of the fourth diode; the cathode of the fourth diode is connected to the gate of the IGBT or the input terminal of the drive push-pull circuit.

[0021] In one possible design, the drive push-pull circuit includes a push-pull circuit and a drive resistor. The input terminal of the push-pull circuit is used to receive the drive signal, and the output terminal of the push-pull circuit is connected to the gate of the IGBT through the drive resistor.

[0022] With the above design, the two transistors in the push-pull circuit can be connected to the positive and negative power supplies respectively. When the amplitude of the received drive signal is different, different transistors can be controlled to turn on, thereby providing a charging path or a power discharge path for the gate of the IGBT, thus controlling the IGBT to turn on or off.

[0023] Secondly, embodiments of this application provide a switching power supply, which may include multiple IGBTs and a driving device provided in the first aspect of this application and any possible design thereof. Each switching transistor is connected to a corresponding driving device. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 A schematic diagram of the structure of a driving device provided in an embodiment of this application. Figure 1 ;

[0026] Figure 2 This is a schematic diagram of the structure of a driving device provided in an embodiment of this application;

[0027] Figure 3 This is a schematic diagram of a drive push-pull circuit provided in an embodiment of this application;

[0028] Figure 4 A schematic diagram of a clamping circuit provided in Embodiment 1 of this application Figure 1 ;

[0029] Figure 5 A schematic diagram of a clamping circuit provided in Embodiment 1 of this application Figure 2 ;

[0030] Figure 6 A schematic diagram of a clamping circuit provided in Embodiment 1 of this application Figure 3 ;

[0031] Figure 7 A schematic diagram of a clamping circuit provided in Embodiment 1 of this application Figure 4 ;

[0032] Figure 8 A schematic diagram of a clamping circuit provided in Embodiment 1 of this application Figure 5 ;

[0033] Figure 9A schematic diagram of a clamping circuit provided in Embodiment 1 of this application Figure 6 ;

[0034] Figure 10 This is a schematic diagram of the structure of a clamping circuit provided in Embodiment 2 of this application. Figure 1 ;

[0035] Figure 11 This is a schematic diagram of the structure of a clamping circuit provided in Embodiment 2 of this application. Figure 2 ;

[0036] Figure 12 This is a schematic diagram of the structure of a clamping circuit provided in Embodiment 2 of this application. Figure 3 ;

[0037] Figure 13 This is a schematic diagram of the structure of a clamping circuit provided in Embodiment 2 of this application. Figure 4 ;

[0038] Figure 14 This is a schematic diagram of the structure of a clamping circuit provided in Embodiment 3 of this application. Figure 1 ;

[0039] Figure 15 This is a schematic diagram of the structure of a clamping circuit provided in Embodiment 3 of this application. Figure 2 ;

[0040] Figure 16 This is a schematic diagram of the structure of a clamping circuit provided in Embodiment 3 of this application. Figure 3 ;

[0041] Figure 17 This is a schematic diagram of the structure of a clamping circuit provided in Embodiment 3 of this application. Figure 4 . Detailed Implementation

[0042] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0043] The terminology used in the implementation section of this application is only for explaining specific embodiments of this application and is not intended to limit this application. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this application.

[0044] The following explanations of some terms used in the embodiments of this application are provided to facilitate understanding by those skilled in the art.

[0045] The terms "first," "second," etc., used in the embodiments of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein.

[0046] In this application's embodiments, "multiple" refers to two or more, and other quantifiers are similar. In this application's embodiments, "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone, where A and B can be singular or plural.

[0047] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. The IGBTs provided in the embodiments of this application can be applied to switching power supplies or other devices with switching, rectification, or inversion functions. The switching power supply can be connected in a power supply scenario and between the power supply and the load. The switching power supply can realize the conversion between the power supply voltage and the load supply voltage, and provide a stable supply voltage to the load. The switching power supply can output voltages of different power types and different voltage amplitudes; that is, it can be connected to loads powered by DC or AC. Depending on the type of power supply and the load, the switching power supply can have different circuit topologies, which will not be described in detail here.

[0048] In practical applications, IGBTs can interrupt large currents. Therefore, during the IGBT turn-off process, the rapid change of large current on the main circuit will cause the stray inductance inside the IGBT to generate a high-amplitude spike voltage. When the spike voltage is applied to the emitter and collector of the IGBT, it will cause overvoltage breakdown of the IGBT, leading to IGBT failure.

[0049] Based on this, embodiments of this application provide a driving device and a switching power supply for realizing the safe shutdown of IGBTs and ensuring the operational reliability of IGBTs.

[0050] See Figure 1 The diagram shown is a structural schematic of a driving device provided in an embodiment of this application. Figure 1 As shown, the driving device may include a drive push-pull circuit and a clamping circuit.

[0051] The push-pull drive circuit has an input terminal for receiving drive signals and an output terminal connected to the gate G of the IGBT. The clamping circuit has a first terminal connected to the gate G and a second terminal connected to the emitter E. The clamping circuit adjusts the gate voltage of the IGBT when the voltage difference between the gate G and the main power terminal E of the emitter exceeds a preset threshold. The preset threshold can be set based on the IGBT's breakdown voltage; this application does not impose further limitations on it.

[0052] In practical applications, since the gate G potential of the IGBT is related to the amplitude of the drive signal received at the input of the push-pull drive circuit, the drive device provided in this application embodiment can also adjust the gate G voltage of the IGBT by adjusting the amplitude of the drive signal received by the push-pull drive circuit. For example, see... Figure 2 As shown, the input terminal of the drive push-pull circuit is used to receive the drive signal, and the output terminal of the drive push-pull circuit is connected to the gate G of the IGBT; the first terminal of the clamping circuit is connected to the input terminal of the drive push-pull circuit, and the second terminal of the clamping circuit is connected to the emitter main power terminal E of the IGBT. The clamping circuit is used to raise the gate G voltage of the IGBT by adjusting the amplitude of the drive signal received at the input terminal of the drive push-pull circuit when the voltage difference between the emitter main power terminal E of the IGBT and the input terminal of the drive push-pull circuit is greater than a preset threshold.

[0053] It should be understood that, Figure 1 and Figure 2 The structure of the drive device shown is for illustrative purposes only. In practical applications, the drive device can have more advanced features than... Figure 1 The components shown may include other protective devices, for example, in the switching circuit; however, this application does not impose further limitations on these components.

[0054] See Figure 1 and Figure 2 As shown, the driving device includes a push-pull circuit, which drives the IGBT to turn on and off based on the amplitude of the driving signal received at its input. For example, when the input of the push-pull circuit receives a high-level driving signal, the push-pull circuit can drive the IGBT to turn on. When the input of the push-pull circuit receives a low-level driving signal, the push-pull circuit drives the IGBT to turn off. The driving signal can be sent by an external controller.

[0055] In practical applications, the drive push-pull circuit can adopt a commonly used industry-standard drive push-pull structure. For example, it can consist of a push-pull circuit and a drive resistor. The input of the push-pull circuit can receive drive signals from external controllers, and the output of the push-pull circuit can be connected to the gate G of the IGBT through the drive resistor. See also Figure 3As shown, the push-pull circuit can be composed of two transistors T1 and T2, and bias resistors Rb for these two transistors. When the input terminal B of the push-pull circuit receives a high-level drive signal, transistor T1 turns on and transistor T2 turns off. The +15V power supply connected to transistor T1 charges the gate G of the IGBT through the drive resistor Rz. When the gate G of the IGBT is fully charged, the IGBT turns on. When the input terminal B of the push-pull circuit receives a low-level drive signal, transistor T2 turns on and transistor T1 turns off. Transistor T2 provides a path for the gate G of the IGBT to discharge energy. When the energy stored in the gate G is fully released, the IGBT turns off.

[0056] See also Figure 1 and Figure 2 As shown, in addition to the drive push-pull circuit used to drive the IGBT to turn on and off, the drive device also includes a clamping circuit. The clamping circuit can be connected between the main power emitter terminal E and the gate G of the IGBT, or it can be connected between the main power emitter terminal E of the IGBT and the input terminal B of the push-pull circuit. During the IGBT turn-off process, the potential of the IGBT's gate G gradually decreases, and the current between the main power emitter terminal E and the collector C of the IGBT also decreases rapidly. This rapid change in current causes an induced voltage to be generated on the stray inductance inside the IGBT. This induced voltage will cause the potential of the main power emitter terminal E of the IGBT to increase, and the voltage difference between the main power emitter terminal E and the gate G of the IGBT, or between the main power emitter terminal E and the input terminal B of the drive push-pull circuit, will increase. When the voltage difference between the main power terminal E of the IGBT emitter and the gate G of the IGBT increases to the preset threshold for the clamping circuit to operate, or when the voltage difference between the main power terminal E of the IGBT emitter and the input terminal B of the push-pull circuit increases to the preset threshold for the clamping circuit to operate, the clamping circuit directly raises the gate G voltage of the IGBT or raises the gate G voltage of the IGBT by adjusting the amplitude of the drive signal at the input terminal B of the push-pull circuit. When the gate G potential of the IGBT increases, the turn-off speed of the IGBT decreases, the rate of change of current in the line decreases, and the induced voltage generated by stray inductance is prevented from further increasing to the breakdown voltage of the IGBT, thus ensuring the normal turn-off of the IGBT.

[0057] In practical use, depending on the number and type of clamping devices, the clamping circuit can have several different circuit topologies. The following examples will introduce several circuit topologies of the clamping circuit.

[0058] Example 1

[0059] The clamping circuit is connected between the gate G and the emitter main power terminal E of the IGBT, or between the input terminal B of the drive push-pull circuit and the emitter main power terminal E of the IGBT. The clamping circuit can consist of a bidirectional transient voltage suppressor (TVS) or two unidirectional TVSs.

[0060] See Figure 4 and Figure 5 The diagram shown is a schematic of the clamping circuit configured with a bidirectional TVS. Figure 4 As shown, during IGBT turn-off, the current between the IGBT's emitter power terminal E and collector C drops rapidly. Because the IGBT has stray inductance, and inductors have the characteristic that current cannot change abruptly, this stray inductance generates an induced voltage to suppress the rapid current drop. The IGBT's emitter power terminal E has a stray inductance Le. When IGBT turn-off causes a rapid drop in current between the emitter power terminal E and collector C, the spike voltage generated by the stray inductance Le causes the potential at the IGBT's emitter power terminal E to rise, potentially breaking down the TVS. The breakdown current flows through the TVS into the IGBT's gate G, increasing the gate voltage and slowing the IGBT's turn-off rate. This reduces the rate of current change in the circuit, limiting the spike voltage amplitude and preventing it from rising further to the IGBT's breakdown voltage, thus protecting the IGBT from safe turn-off. Similarly, as... Figure 5 As shown, when the IGBT is turned off, causing a rapid decrease in the current between the IGBT's emitter main power terminal E and collector C, the spike voltage generated by the stray inductance Le will cause the potential of the IGBT's emitter main power terminal E to rise and break down the TVS. The breakdown current flows through the TVS into the input terminal B of the push-pull circuit, raising the amplitude of the drive signal received by the push-pull circuit to raise the gate voltage G of the IGBT. The IGBT's turn-off rate decreases, thereby reducing the rate of change of current on the line, achieving the purpose of limiting the amplitude of the spike voltage, preventing the generated spike voltage from rising to the IGBT's breakdown voltage, and protecting the IGBT from safe turn-off.

[0061] See Figure 6 and Figure 7 The diagram shows a clamping circuit consisting of two unidirectional TVSs. Figure 6 and Figure 7 As shown, the clamping circuit includes a first unidirectional TVS1 and a second unidirectional TVS2. The cathode of the first unidirectional TVS1 is connected to the gate G of the IGBT or the input terminal B of the push-pull circuit. The anode of the first unidirectional TVS1 is connected to the anode of the second unidirectional TVS2. The cathode of the second unidirectional TVS2 is connected to the emitter main power terminal E of the IGBT. See also... Figure 6As shown, when the IGBT is turned off, causing a rapid decrease in current between the IGBT's emitter power terminal E and collector C, the spike voltage generated by the stray inductance Le will cause the potential of the IGBT's emitter power terminal E to rise, breaking down TVS2. The breakdown current flows into the IGBT's gate (G) through TVS2 and TVS1, increasing the gate voltage (G) to slow down the IGBT's turn-off rate, thereby reducing the rate of current change in the circuit and preventing the generated spike voltage from rising further to the IGBT's breakdown voltage, thus protecting the IGBT from safe turn-off. Similarly, as... Figure 7 As shown, when the IGBT is turned off, causing a rapid drop in current between the IGBT's emitter power terminal E and collector C, the stray inductance Le generates a voltage spike that raises the potential at the IGBT's emitter E, causing TVS3 to break down. The breakdown current flows through TVS4 and TVS3 into the input terminal B of the push-pull circuit. The amplitude of the drive signal received by the push-pull circuit increases, thereby raising the IGBT's gate voltage G, slowing down the IGBT's turn-off rate, further reducing the rate of current change on the line, and limiting the amplitude of the voltage spike. This prevents the generated voltage spike from rising further to the IGBT's breakdown voltage, ensuring the safe turn-off of the IGBT. When TVS1 breaks down, since TVS functions like a regular diode during forward energy transfer, TVS2 can be used to prevent reverse energy transfer.

[0062] It should be noted that, Figure 6 and Figure 7 The clamping circuit structure shown is for illustrative purposes only. In practical applications, the polarities of TV1 and TVS2 can be reversed. For example, see [link to example]. Figure 8 and Figure 9 As shown, the clamping circuit includes a third unidirectional TVS3 and a fourth unidirectional TVS4. The anode of the third unidirectional TVS3 is connected to the gate G of the IGBT or the input terminal B of the push-pull circuit, the cathode of the third unidirectional TVS3 is connected to the cathode of the fourth unidirectional TVS4, and the anode of the fourth unidirectional TVS4 is connected to the emitter main power terminal E of the IGBT.

[0063] Example 2

[0064] The clamping circuit is connected between the gate (G) and emitter (E) of the IGBT, or between the input terminal (B) of the push-pull drive circuit and the emitter (E) of the IGBT. The clamping circuit can consist of a unidirectional TVS diode and a diode to prevent reverse power transfer.

[0065] In some implementations, the clamping circuit includes a fifth unidirectional TVS5 and a first diode D1.

[0066] Specifically, the anode of the fifth unidirectional TVS5 is connected to the gate G of the IGBT or the input terminal B of the push-pull circuit, the cathode of the fifth unidirectional TVS5 is connected to the cathode of the first diode D1, and the anode of the first diode D1 is connected to the emitter main power terminal E of the IGBT. The structure of the clamping circuit when the anode of the fifth unidirectional TVS5 is connected to the gate G of the IGBT can be found in [reference needed]. Figure 10 As shown, the structure of the clamping circuit when the anode of the fifth unidirectional TVS5 is connected to the input terminal B of the push-pull circuit can be found in [reference needed]. Figure 11 As shown.

[0067] See Figure 10 As shown, when the IGBT is turned off, causing a rapid decrease in current between the IGBT's emitter power terminal E and collector C, the spike voltage generated by the stray inductance Le will cause the potential of the IGBT's emitter power terminal E to rise, breaking down TVS5. The breakdown current flows into the IGBT's gate (G) through D1 and TVS5, increasing the gate voltage (G) to slow down the IGBT's turn-off rate, thereby reducing the rate of current change in the circuit and preventing the generated spike voltage from rising further to the IGBT's breakdown voltage, thus protecting the IGBT from safe turn-off. Similarly, as... Figure 11 As shown, when the IGBT is turned off, causing a rapid decrease in the current between the IGBT's emitter main power terminal E and collector C, the spike voltage generated by the stray inductance Le will cause the potential of the IGBT's emitter main power terminal E to rise and break down TVS5. The breakdown current flows into the input terminal B of the push-pull circuit through D1 and TVS5, increasing the amplitude of the drive signal received by the push-pull circuit, thereby raising the IGBT's gate voltage G, slowing down the IGBT's turn-off rate, further reducing the rate of current change on the line, and limiting the amplitude of the spike voltage. This prevents the generated spike voltage from rising further to the IGBT's breakdown voltage, protecting the IGBT from being safely turned off.

[0068] In some implementations, the clamping circuit includes a sixth unidirectional TVS6 and a second diode D2.

[0069] Specifically, the cathode of the sixth unidirectional TVS6 is connected to the emitter main power terminal E of the IGBT, and the anode of the sixth unidirectional TVS6 is connected to the anode of the second diode D2; the cathode of the second diode D2 is connected to the gate G of the IGBT or the input terminal B of the drive push-pull circuit. The structure of the clamping circuit when the cathode of the second diode D2 is connected to the gate G of the IGBT can be found in [reference needed]. Figure 12 As shown, the structure of the clamping circuit when the cathode of the second diode D2 is connected to the input terminal B of the push-pull circuit can be found in [reference needed]. Figure 13 As shown.

[0070] It should be noted that, Figure 12 and Figure 13 The clamping circuit structure shown is similar to Figure 10 and Figure 11 The clamping circuit structure shown only interchanges the connection positions of the diode and the unidirectional TVS. Therefore, Figure 12 and Figure 13 The working principle of the clamping circuit shown is the same as Figure 10 and Figure 11 The clamping circuit shown operates on the same principle, and will not be described again here.

[0071] Example 3

[0072] The clamping circuit is connected between the gate G of the IGBT and the main power terminal E of the emitter, or between the input terminal B of the push-pull drive circuit and the main power terminal E of the IGBT. The clamping circuit can consist of a Zener diode and a diode to prevent reverse power transfer.

[0073] In some embodiments, the clamping circuit includes a first Zener diode Z1 and a third diode D3.

[0074] Specifically, the anode of the first Zener diode Z1 is connected to the gate G of the IGBT or the input terminal B of the push-pull circuit, and the cathode of the first Zener diode Z1 is connected to the cathode of the third diode D3; the anode of the third diode D3 is connected to the emitter main power terminal E of the IGBT. The structure of the clamping circuit when the anode of the first Zener diode Z1 is connected to the gate G of the IGBT can be found in [reference needed]. Figure 14 As shown, the structure of the clamping circuit when the anode of the first Zener diode Z1 is connected to the input terminal B of the push-pull circuit can be found in [reference needed]. Figure 15 As shown.

[0075] join Figure 14 As shown, when the IGBT is turned off, causing a rapid decrease in current between the IGBT's emitter main power terminal E and collector C, the spike voltage generated by the stray inductance Le will cause the potential of the IGBT's emitter main power terminal E to rise. When the voltage of the emitter main power terminal E1 exceeds the breakdown voltage of Z1, Z1 breaks down. The breakdown current flows into the IGBT's gate G through D1 and Z1, increasing the IGBT's gate G voltage to slow down the IGBT's turn-off rate, thereby reducing the rate of current change in the circuit and preventing the generated spike voltage from rising further to the IGBT's breakdown voltage, thus protecting the IGBT from safe turn-off. Similarly, as... Figure 15As shown, when the IGBT is turned off, causing a rapid decrease in the current between the IGBT's emitter main power terminal E and collector C, the spike voltage generated by the stray inductance Le will cause the potential of the IGBT's emitter main power terminal E to rise and break down Z1. The breakdown current flows into the input terminal B of the push-pull circuit through D3 and Z1, increasing the amplitude of the drive signal received by the push-pull circuit, thereby raising the IGBT's gate voltage G, slowing down the IGBT's turn-off rate, further reducing the rate of change of current on the line, and limiting the amplitude of the spike voltage. This prevents the generated spike voltage from rising further to the IGBT's breakdown voltage, thus protecting the IGBT from being turned off safely.

[0076] In some implementations, the clamping circuit includes a second Zener diode Z2 and a fourth diode D4.

[0077] Specifically, the cathode of the second Zener diode Z2 is connected to the emitter power terminal E of the IGBT, and the anode of the second Zener diode Z2 is connected to the anode of the fourth diode D4; the cathode of the fourth diode D4 is connected to the gate G of the IGBT or the input terminal B of the push-pull circuit. The structure of the clamping circuit when the cathode of the fourth diode D4 is connected to the gate G of the IGBT can be found in [reference needed]. Figure 16 As shown, the structure of the clamping circuit when the cathode of the fourth diode D4 is connected to the input terminal B of the push-pull circuit can be found in [reference needed]. Figure 17 As shown.

[0078] It should be noted that, Figure 16 and Figure 17 The clamping circuit structure shown is similar to Figure 14 and Figure 15 The clamping circuit structure shown only interchanges the connection positions of the diode and the Zener diode; therefore, Figure 16 and Figure 17 The working principle of the clamping circuit shown is the same as Figure 14 and Figure 15 The clamping circuit shown operates on the same principle, and will not be described again here.

[0079] In practical applications, all components of the drive unit can be fixed on a single device. This device is equipped with multiple fixed interfaces, through which IGBTs or other devices can connect to the drive unit. Alternatively, the drive unit can be packaged with the IGBT within a single chip. For example, a switching power supply may include multiple IGBTs, with each IGBT and its driver integrated into a single package. Of course, the drive unit can also employ other mounting methods, which are not limited here.

[0080] Based on the above description, this application also provides a switching power supply, which can be applied in power supply scenarios, connected between the power supply and the load, and provides a stable power supply voltage to the load. The switching power supply may include multiple IGBTs and multiple aforementioned driving devices, with each switching transistor connected to each driving device in a one-to-one correspondence.

[0081] In practical applications, the structure of a switching power supply can be configured according to the power supply type of the load and the power source. For example, if the external power supply to the switching power supply is AC, and the load uses DC power, multiple IGBTs can form a rectifier circuit to convert the AC output from the AC power supply into DC power to supply power to the load. If the external power supply to the switching power supply is DC, and the load operates on AC, multiple IGBTs can form an inverter circuit to convert the DC output from the DC power supply into AC power to supply power to the load.

[0082] In practical applications, switching power supplies can also include other components. For example, in order to improve the power efficiency of switching power supplies, they can also include multiple inductors, which can form a power factor correction (PFC) circuit with multiple IGBTs.

[0083] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A driving device, characterized in that, include: Drive push-pull circuit and clamping circuit; The input terminal of the drive push-pull circuit is used to receive drive signals, and the output terminal of the drive push-pull circuit is connected to the gate of the IGBT. The first end of the clamping circuit is connected to the gate of the IGBT or the input end of the drive push-pull circuit, and the second end of the clamping circuit is connected to the emitter main power terminal of the IGBT.

2. The driving device according to claim 1, characterized in that, The clamping circuit includes a bidirectional transient voltage suppressor.

3. The driving device according to claim 1, characterized in that, The clamping circuit includes: a first unidirectional transient voltage suppressor and a second unidirectional transient voltage suppressor; The cathode of the first unidirectional transient voltage suppressor is connected to the gate of the IGBT or the input terminal of the drive push-pull circuit, and the anode of the first unidirectional transient voltage suppressor is connected to the anode of the second unidirectional transient voltage suppressor. The cathode of the second unidirectional transient voltage suppressor is connected to the emitter main power terminal of the IGBT.

4. The driving device according to claim 1, characterized in that, The clamping circuit includes: a third unidirectional transient voltage suppressor and a fourth unidirectional transient voltage suppressor; The anode of the third unidirectional transient voltage suppressor is connected to the gate of the IGBT or the input terminal of the drive push-pull circuit, and the cathode of the third unidirectional transient voltage suppressor is connected to the cathode of the fourth unidirectional transient voltage suppressor. The anode of the fourth unidirectional transient voltage suppressor is connected to the emitter main power terminal of the IGBT.

5. The driving device according to claim 1, characterized in that, The clamping circuit includes: a fifth unidirectional transient voltage suppressor and a first diode; The anode of the fifth unidirectional transient voltage suppressor is connected to the gate of the IGBT or the input terminal of the drive push-pull circuit, and the cathode of the fifth unidirectional transient voltage suppressor is connected to the cathode of the first diode. The anode of the first diode is connected to the emitter main power terminal of the IGBT.

6. The driving device according to claim 1, characterized in that, The clamping circuit includes: a sixth unidirectional transient voltage suppressor and a second diode; The cathode of the sixth unidirectional transient voltage suppressor is connected to the main power terminal of the emitter of the IGBT, and the anode of the sixth unidirectional transient voltage suppressor is connected to the anode of the second diode. The cathode of the second diode is connected to the gate of the IGBT or the input terminal of the drive push-pull circuit.

7. The driving device according to claim 1, characterized in that, The clamping circuit includes: a first Zener diode and a third diode; The anode of the first Zener diode is connected to the gate of the IGBT or the input terminal of the drive push-pull circuit, and the cathode of the first Zener diode is connected to the cathode of the third diode. The anode of the third diode is connected to the emitter main power terminal of the IGBT.

8. The driving device according to claim 1, characterized in that, The clamping circuit includes: a second Zener diode and a fourth diode; The cathode of the second Zener diode is connected to the main power terminal of the emitter of the IGBT, and the anode of the second Zener diode is connected to the anode of the fourth diode. The cathode of the fourth diode is connected to the gate of the IGBT or the input terminal of the drive push-pull circuit.

9. The driving device according to any one of claims 1 to 8, characterized in that, The drive push-pull circuit includes a push-pull circuit and a drive resistor. The input terminal of the push-pull circuit is used to receive the drive signal, and the output terminal of the push-pull circuit is connected to the gate of the IGBT through the drive resistor.

10. A switching power supply, characterized in that, It includes multiple switching transistors and multiple driving devices as described in any one of claims 1 to 9; wherein each switching transistor is connected to each driving device in a one-to-one correspondence.

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