Circuit for protecting gate drive power tube

Abstract

The utility model discloses a circuit for protecting a grid driving power tube, which comprises a power supply module, an input interface, a logic control module, a high-side driver, a low-side driver, a high-side power tube, a low-side power tube, a high-side strong pull-down circuit and a low-side strong pull-down circuit, the output supplies power to the logic control module, the high-side driver and the low-side driver; the input interface is connected with an external input signal and is converted into a logic level signal to be output and connected with the logic control module; the logic control module is used for performing logic processing on an input signal so as to output a corresponding control signal to control the high-side drive and the low-side drive; the high-side driver is used for outputting high-side voltage HO to control the high-side power tube; the low-side driver outputs low-side voltage LO to control the low-side power tube; the input end of the high-side strong pull-down circuit is connected with one output end of the logic control module, and the output end is connected with the grid electrode of the high-side power tube for forcibly pulling down the grid electrode level of the high-side power tube to a low level.

Description

Technical Field

[0001] The utility model belongs to the technical field of electronic circuits, and in particular relates to a circuit for protecting a gate drive power tube. Background Art

[0002] The gate driver integrates high-voltage power devices and low-voltage circuits into the same chip. It combines power electronics with semiconductor technology, gradually replaces traditional discrete components, and is increasingly used in high-power GaN, SiC, IGBT, MOSFET and other driving fields. Gate drivers are commonly used in various motor drives, lighting, communication power supplies, photovoltaic inverters, etc. Traditional gate drivers are divided into high-side drivers and low-side drivers, which drive the upper bridge arm power tube and the lower bridge arm power tube respectively. If the driven upper bridge arm power tube is turned on, at the moment of turning on, the source voltage of the upper bridge arm will be instantly pulled up to the power supply voltage. Due to the parasitic capacitance between the drain and gate ends of the lower bridge arm power tube, the high voltage at the drain end of the lower bridge arm will be transmitted to the gate end through the parasitic capacitance at the gate drain end, generating a high-voltage pulse, which can easily cause the lower bridge arm power tube to burn out. The conduction principle of the upper-arm power tube and the lower-arm power tube is the same. When the power supply VM is powered on, due to the parasitic capacitance between the drain and gate ends of the upper-arm power tube, the high voltage at the drain end of the upper-arm will be transmitted to the gate end through the parasitic capacitance at the gate-drain end, generating a high-voltage pulse, which can easily cause the upper-arm power tube to burn out. Utility Model Content

[0003] In view of the above problems, the utility model provides a circuit for protecting a gate drive power tube.

[0004] In order to solve the above technical problems, the utility model adopts the following technical solutions:

[0005] A circuit for protecting a gate drive power tube comprises a power module, an input interface, a logic control module, a high-side drive, a low-side drive, a high-side power tube, a low-side power tube, a high-side strong pull-down circuit and a low-side strong pull-down circuit, wherein the input of the power module is connected to a power source, and the output is used to supply power to the logic control module, the high-side drive and the low-side drive; the input interface is connected to an external input signal, converted into a logic level signal and outputted to the logic control module; the logic control module is used to perform logic processing on the input signal, thereby outputting a corresponding control signal to control the high-side drive and the low-side drive; the high-side drive is used to output a high-side voltage HO to control the high-side power tube; the low-side drive outputs a low-side voltage LO to control the low-side power tube; the input end of the high-side strong pull-down circuit is connected to an output end of the logic control module, and the output end is connected to the high-side power tube gate, so as to forcibly pull the high-side power tube gate level down to a low level; the input end of the low-side strong pull-down circuit is connected to an output end of the logic control module, and the output end is connected to the low-side power tube gate, so as to forcibly pull the low-side power tube gate level down to a low level.

[0006] In a possible implementation manner, the low-side strong pull-down circuit includes a first inverter, a second inverter, a NOR gate, a third inverter, a NAND gate, a fourth inverter, a fifth inverter and an NMOS tube which are connected in series in sequence.

[0007] In a possible implementation manner, the high-side power tube is an NMOS power tube.

[0008] In a possible implementation manner, the low-side power tube is an NMOS power tube.

[0009] In one possible implementation, the power supply module further includes a linear regulator and a charge pump, wherein the linear regulator is used to provide a low-voltage power supply for the logic control module and the low-side driver, and the charge pump is used to output a voltage higher than the power supply voltage VM to power the high-side driver.

[0010] The utility model has the following beneficial effects:

[0011] (1) When VM is powered on, the high-side strong pull-down circuit forces the gate of the high-side power tube to be at a low level, thereby effectively protecting the high-side power tube from being burned; when the high-side drive output HO is high voltage, the strong pull-down circuit forces the gate of the low-side power tube to be at a low level, thereby effectively protecting the low-side power tube from being burned, and the reliability is high.

[0012] (2) The circuit structure is simple, the power consumption is low and the applicability is strong. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 A circuit schematic diagram of a circuit for protecting a gate drive power tube according to an embodiment of the utility model;

[0014] Figure 2 The present invention is a schematic structural diagram of a strong pull-down circuit in a circuit for protecting a gate drive power tube according to an embodiment of the present invention. DETAILED DESCRIPTION

[0015] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0016] Reference Figure 1 , shown is a circuit for protecting a gate drive power tube according to an embodiment of the utility model, including a power module 18, an input interface 19, a logic control module 20, a high-side driver 21, a low-side driver 22, a high-side power tube 25, a low-side power tube 26, a high-side strong pull-down circuit 28 and a low-side strong pull-down circuit 27, wherein the power module 18 input is connected to a power supply VM, and the output is used to supply power to the logic control module 20, the high-side driver 25 and the low-side driver 26; the input interface 19 is connected to an external input signal, converted into a logic level signal output connected to the logic control module 20; the logic control module 20 is used to perform logic on the input signal The logic is processed to output corresponding control signals to control the high-side driver 21 and the low-side driver 22; the high-side driver 21 is used to output a high-side voltage HO to control the high-side power tube 25; the low-side driver 22 outputs a low-side voltage LO to control the low-side power tube 26; the input end of the high-side strong pull-down circuit 28 is connected to an output end of the logic control module, and the output end is connected to the gate of the high-side power tube, which is used to force the gate level of the high-side power tube to be pulled down to a low level; the input end of the low-side strong pull-down circuit 27 is connected to an output end of the logic control module 20, and the output end is connected to the gate of the low-side power tube 26, which is used to force the gate level of the low-side power tube 26 to be pulled down to a low level.

[0017] In another embodiment of the utility model, a circuit for protecting a gate drive power tube is provided, wherein the power module 18 further includes a linear regulator and a charge pump, wherein the linear regulator is used to provide a low-voltage power supply for a logic control module 20 and a low-side driver 22, and the charge pump is used to output a voltage higher than the power supply voltage VM to power the high-side driver.

[0018] By means of the circuit for protecting the gate drive power tube set above, when the external power supply VM supplies power within the normal working voltage range, the input signal IN1 / IN2 is transmitted to the logic control module 20, and the logic control module 20 generates a control signal to control the high-side driver 21 and the low-side driver 22, so that the high-side driver 21 and the low-side driver 22 output high and low levels to control the external power tube to turn on and off. The HO of the high-side driver 21 drives the high-side power tube 25, and the LO of the low-side driver drives the low-side power tube 26. When the HO output of the high-side power tube 25 is high, the high-side power tube 25 is turned on. At the moment of turning on, the source end of the high-side power tube 25 will be instantly pulled up to the power supply voltage, thereby causing the drain end of the low-side power tube 26 to also be the power supply voltage. Since there is a parasitic capacitor 24 at the gate-drain end of the low-side power tube 26, the high voltage at the drain end of the low-side power tube 26 will be instantly transmitted to the gate end through the parasitic capacitor at the gate-drain end, so that the gate end voltage of the low-side power tube 26 is instantly pulled up, which can easily cause the low-side power tube 26 to burn directly. A low-side strong pull-down circuit 27 is added to the output terminal LO of the low-side driver 22. The low-side strong pull-down circuit 27 is used to force the gate level of the low-side power tube 26 to be pulled down to a low level when it is working. When the high-side driver 20 receives the output HO as a high-voltage control signal, the low-side strong pull-down circuit 27 will also receive a control signal, and the control signal forces the strong pull-down circuit output to be a low level, thereby ensuring that when the drain end of the low-side power tube 26 is at a high level, the gate end of the low-side power tube 26 will not be pulled up through the parasitic capacitance of the gate-drain end, thereby effectively protecting the low-side power tube 26 from being burned. When VM is powered on, due to the parasitic capacitance 23 between the gate and drain of the high-side power tube 25, the gate of the high-side power tube 25 is easy to generate a high-voltage pulse in an instant, thereby causing the high-side power tube 25 to burn. A high-side strong pull-down circuit 28 is added to the output end of the high-side driver 21. When the high-side strong pull-down circuit 28 is working, it is used to forcibly pull down the gate level of the high-side power tube 25 to a low level, thereby effectively protecting the high-side power tube 25 from being burned.

[0019] Specifically, a circuit for protecting a gate drive power tube according to an embodiment of the utility model, a low-side strong pull-down circuit comprises a first inverter 30, a second inverter 31, a NOR gate 32, a third inverter 33, a NAND gate 34, a fourth inverter 35, a fifth inverter 36 and an NMOS tube 37 connected in series in sequence. The gate of the NMOS tube 37 is connected to the output end of the fifth inverter 36, the source is grounded, and the drain is connected to the gate of the low-side power tube. The high-side power tube and the low-side power tube are NMOS power tubes. When the logic control 18 outputs a low-level signal to LIN, the inverter 36 outputs a high level to drive the NMOS tube 37 to turn on, and the drain end LO of the NMOS tube 37 will pull down the level of the circuit. The structure of the high-side strong pull-down circuit can be implemented with reference to the low-side strong pull-down circuit, which will not be repeated here.

[0020] It should be understood that the exemplary embodiments described herein are illustrative rather than restrictive. Although one or more embodiments of the present invention are described in conjunction with the accompanying drawings, it should be understood by those skilled in the art that various changes in form and detail may be made without departing from the spirit and scope of the present invention as defined by the appended claims.

Claims

1. A circuit for protecting a gate drive power tube, characterized in that: It includes a power module, an input interface, a logic control module, a high-side driver, a low-side driver, a high-side power tube, a low-side power tube, a high-side strong pull-down circuit and a low-side strong pull-down circuit. The power module input is connected to a power source, and the output is used to supply power to the logic control module, the high-side driver and the low-side driver; the input interface is connected to an external input signal, which is converted into a logic level signal and output to the logic control module; The logic control module is used to perform logic processing on the input signal, thereby outputting corresponding control signals to control the high-side drive and the low-side drive; the high-side drive is used to output a high-side voltage HO to control the high-side power tube; the low-side drive outputs a low-side voltage LO to control the low-side power tube; the input end of the high-side strong pull-down circuit is connected to an output end of the logic control module, and the output end is connected to the gate of the high-side power tube, which is used to force the gate level of the high-side power tube to be pulled down to a low level; the input end of the low-side strong pull-down circuit is connected to an output end of the logic control module, and the output end is connected to the gate of the low-side power tube, which is used to force the gate level of the low-side power tube to be pulled down to a low level.

2. The circuit for protecting a gate drive power tube according to claim 1, characterized in that: The low-side strong pull-down circuit comprises a first inverter, a second inverter, a NOR gate, a third inverter, a NAND gate, a fourth inverter, a fifth inverter and an NMOS tube which are connected in series in sequence.

3. The circuit for protecting a gate drive power tube according to claim 1, characterized in that: The high-side power tube is an NMOS power tube.

4. The circuit for protecting a gate drive power tube according to claim 1, characterized in that: The low-side power tube is an NMOS power tube.

5. The circuit for protecting a gate drive power tube according to any one of claims 1 to 4, characterized in that: The power supply module further includes a linear regulator and a charge pump, wherein the linear regulator is used to provide a low-voltage power supply for the logic control module and the low-side driver, and the charge pump is used to output a voltage higher than the power supply voltage VM to power the high-side driver.

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