N-mos high-side driver and fast turn-off circuit

Abstract

The application discloses an N-MOS high-side driving and fast turn-off circuit, which comprises a gate driving switch circuit U1, a fast turn-off circuit, a first resistor R1 and an N-MOS T1, a control signal end CON0 is connected with one end of the first resistor R1 and the fast turn-off circuit, the gate driving switch circuit is connected with a gate driving voltage end VG and the other end of the first resistor R1, an output end of the gate driving switch circuit is connected with a gate of the N-MOS, a drain of the N-MOS is connected with a system power voltage end, the other input end of the fast turn-off circuit is connected with the other end of the first resistor R1, an output end of the fast turn-off circuit is connected with a gate of the N-MOS T1, and a source of the N-MOS T1 is connected with a load as an output end Vout.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of electronic circuits, and particularly relates to an N-MOS high-side drive and fast turn-off circuit. BACKGROUND

[0002] In modern automotive electronic systems, the body control module is responsible for managing the driving of loads such as vehicle lights, wipers, door and window motors, etc. To improve reliability and integration, the current mainstream solution uses high-side drive intelligent power MOSFET (hereinafter referred to as "intelligent MOS"). This type of device integrates MOSFET, drive circuit, protection function (such as overcurrent, overheat, short circuit protection) into a single chip, and users only need to provide high and low level signals to control the load, greatly simplifying system design.

[0003] However, the existing high-side intelligent MOS solution has the following problems: (1) high cost: intelligent MOS is significantly more expensive than ordinary MOSFET due to its high integration, resulting in an increase in the overall BOM cost of the body control system. (2) Limited selection of models: intelligent MOS is usually supplied by a few semiconductor manufacturers, and the selection of parameters such as packaging and current level is limited, making it difficult to meet diverse needs. (3) Low design flexibility: high-side drive requires specific intelligent MOS, and if the load characteristics need to be adjusted (such as higher voltage / current), the entire solution may need to be replaced, resulting in a long development cycle. SUMMARY

[0004] In view of the above problems, the application provides an N-MOS high-side drive and fast turn-off circuit.

[0005] To solve the above technical problems, the application adopts the following technical solution:

[0006] An N-MOS high-side drive and fast turn-off circuit, comprising a gate drive switch circuit U1, a fast turn-off circuit, a first resistor R1, and an N-MOS transistor T1, a control signal end CON0 is connected to one end of the first resistor R1 and the fast turn-off circuit, the gate drive switch circuit is connected to a gate drive voltage end VG and the other end of the first resistor R1, the gate drive switch circuit output end is connected to the gate of the N-MOS transistor, the drain of the N-MOS transistor is connected to a system power supply voltage end, the other input end of the fast turn-off circuit is connected to the other end of the first resistor R1, the output end of the fast turn-off circuit is connected to the gate of the N-MOS transistor T1, and the source of the N-MOS transistor T1 is connected to a load as an output end Vout.

[0007] In a possible implementation, the fast turn-off circuit comprises a diode D1, an inverter U2, a capacitor C1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, and an NPN triode Q1, a positive electrode of the diode D1 is connected to a control signal end CON0, a negative electrode of the diode D1 is connected to one end of the second resistor R2, the other end of the second resistor R2 is connected to one end of the capacitor C1 and a power input end of the inverter U2 respectively, the other end of the capacitor C1 is grounded, the other end of the first resistor R1 is connected to an input end of the inverter U2 and one end of the third resistor R3, the other end of the third resistor is grounded, one end of the fourth resistor R4 connected to an output end of the inverter U2, the other end of the fourth resistor R4 is connected to one end of the fifth resistor R5, the other end of the fifth resistor R5 is grounded, an emitter of the NPN triode Q1 is grounded, and a collector of the NPN triode Q1 is connected to a gate of the N-MOS transistor T1.

[0008] In a possible implementation, the gate drive switch circuit U1 comprises an electronic switch K1, a sixth resistor R6, and a seventh resistor R7, one end of the electronic switch K1 is connected to a gate drive voltage end VG, the other end of the electronic switch K1 is connected to one end of the seventh resistor R7, the other end of the seventh resistor R7 is connected to one end of the sixth resistor R6 and a gate of the N-MOS transistor T1, and the other end of the sixth resistor R6 is grounded.

[0009] In a possible implementation, when the control signal of the control signal end CON0 changes from low level to high level, the gate drive switch circuit is controlled to work, the gate drive voltage end VG is turned on, the gate voltage of the N-MOS transistor T1 has a drive voltage, the N-MOS transistor T1 is turned on, and the output voltage of the output end Vout of the N-MOS transistor T1 is output.

[0010] In a possible implementation, when the control signal of the control signal end CON0 changes from high level to low level, the one-way conduction of the diode D1 and the energy storage of the capacitor C1 jointly act on the inverter U2 to continue working, when the input end of the inverter U2 is at low level, the output end of the inverter U2 is at high level, so that the NPN triode Q1 works and is turned on, the gate voltage of the N-MOS transistor is rapidly discharged, the fast turn-off of the MOS is completed, and after the capacitor C1 is discharged, the inverter U2 no longer works.

[0011] The application has the following beneficial effects:

[0012] (1) Reducing switching loss: The turn-off time of the N-MOS transistor directly affects the switching loss. Shorter turn-off time can reduce power loss, lower loss means less heat generated, thereby reducing the requirement for the heat dissipation system, and helping to prolong the working life of the N-MOS transistor;

[0013] (2) Improve electromagnetic compatibility: Fast shutdown can reduce voltage and current surges, thereby reducing electromagnetic interference and improving the electromagnetic compatibility of the system.

[0014] (3) Enhanced reliability: Fast turn-off can prevent the MOS transistor from being subjected to excessive stress during the turn-off process, and improve the reliability and lifespan of the device when the drain and source currents of the N-MOS transistor are relatively large. Attached Figure Description

[0015] Figure 1 This is a circuit schematic diagram of an N-MOS transistor high-side drive and fast turn-off circuit according to an embodiment of the present invention. Detailed Implementation

[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] See Figure 1 The diagram shows a circuit schematic of an N-MOS transistor high-side drive and fast turn-off circuit according to an embodiment of the present invention. It includes a gate drive switch circuit U1, a fast turn-off circuit, a first resistor R1, and an N-MOS transistor T1. The control signal terminal CON0 is connected to one end of the first resistor R1 and the fast turn-off circuit. The gate drive switch circuit is connected to the gate drive voltage terminal VG and the other end of the first resistor R1. The output terminal of the gate drive switch circuit is connected to the gate of the N-MOS transistor, and the drain of the N-MOS transistor is connected to the system power supply voltage terminal. The other input terminal of the fast turn-off circuit is connected to the other end of the first resistor R1, and the output terminal of the fast turn-off circuit is connected to the gate of the N-MOS transistor T1. The source of the N-MOS transistor T1 serves as the output terminal Vout and is connected to the load.

[0018] In a specific application example, the fast turn-off circuit includes diode D1, inverter U2, capacitor C1, second resistor R2, third resistor R3, fourth resistor R4, fifth resistor R5 and NPN transistor Q1, the positive pole of diode D1 is connected to control signal end CON0, the negative pole of diode D1 is connected to one end of second resistor R2, the other end of second resistor R2 is connected to one end of capacitor C1 and the power input end of inverter U2 respectively, the other end of capacitor C1 is grounded, the other end of first resistor R1 is connected to the input end of inverter U2 and one end of third resistor R3, the other end of third resistor R3 is grounded, the output end of inverter U2 is connected to one end of fourth resistor R4, the other end of fourth resistor R4 is connected to one end of fifth resistor R5, the other end of fifth resistor R5 is grounded, the emitter of NPN transistor Q1 is grounded, and the collector of NPN transistor Q1 is connected to the gate of N-MOS transistor T1.

[0019] In a specific application example, the gate drive switch circuit U1 includes electronic switch K1, sixth resistor R6 and seventh resistor R7, one end of electronic switch K1 is connected to gate drive voltage end VG, the other end of electronic switch K1 is connected to one end of seventh resistor R7, the other end of seventh resistor R7 is connected to one end of sixth resistor R6 and the gate of N-MOS transistor T1, and the other end of sixth resistor R6 is grounded.

[0020] In the process of opening of N-MOS transistor, when the control signal of control signal end CON0 changes from low level to high level, the gate drive switch circuit is controlled to work, so that the voltage of gate drive voltage end VG is conducted, thereby the gate voltage of N-MOS transistor T1 has driving voltage, N-MOS transistor T1 is conducted, and the output voltage of output end Vout of N-MOS transistor T1 is output. In the process of opening of N-MOS transistor, in the fast turn-off circuit, second resistor R2 and capacitor C1 constitute a delay circuit, although the signal of input end (2 pin) of inverter U2 is low level, due to the effect of delay circuit, in the rising process of input voltage from low to high, inverter U2 is still in non-working state, and the output end (4 pin) of inverter U2 is still low level, which does not affect the charging process of gate of N-MOS transistor.

[0021] In the process of turning off the MOS, when the CON0 control signal changes from high level to low level, the gate drive switch circuit unit disconnects the VG voltage signal, the gate voltage of the MOS is discharged through the sixth resistor R6, and the discharge time of the gate determines the turn-off time of the MOS. In order to improve the load capacity of the VG power supply, in order to make the MOS opening process quickly charge the gate, the larger the sixth resistor R6 is, but it affects the turn-off time of the MOS in the process of turning off the MOS. In order to solve the above-mentioned contradictory problem, a fast turn-off circuit is added, when the control signal of the control signal end CON0 changes from high level to low level, the one-way conduction of the diode D1 and the energy storage of the capacitor C1 jointly act on the inverter U2 to continue to work, when the input end of the inverter U2 is low level, the output end of the inverter U2 is high level, so that the NPN triode Q1 works and turns on, and the gate voltage of the N-MOS is quickly discharged, and after the N-MOS is quickly turned off, the capacitor C1 is discharged, and the inverter U2 no longer works.

[0022] The N-MOS high-side drive and fast turn-off circuit provided above shares one signal for the opening signal and the turn-off signal of the N-MOS, thereby saving the pin resources of the control end MCU. The hardware delay circuit composed of the diode D1, the second resistor R2 and the capacitor C1 does not affect the charging of the MOS gate by the inverter U2 when the N-MOS is turned on. In the process of turning off the N-MOS, the energy storage of the capacitor C1 is used to make the inverter U2 quickly turn off. The working power supply of the inverter U2 is provided by the control signal CON0, so that when the N-MOS is turned off, the inverter and the gate drive switch circuit unit do not consume power, thereby effectively reducing the static power consumption of the system. Directly discharging the gate of the N-MOS makes the size of the sixth resistor R6 and the seventh resistor R7 have no effect on the turn-off of the N-MOS.

[0023] It should be understood that the example embodiments described herein are illustrative and not restrictive. Although one or more embodiments of the application are described in conjunction with the attached figures, it should be understood that various changes in form and detail can be made without departing from the spirit and scope of the application as defined by the appended claims.

Claims

1. A high-side drive and fast turn-off circuit for an N-MOS transistor, characterized in that, The circuit includes a gate drive switch circuit U1, a fast turn-off circuit, a first resistor R1, and an N-MOS transistor T1. The control signal terminal CON0 is connected to one end of the first resistor R1 and the fast turn-off circuit. The gate drive switch circuit is connected to the gate drive voltage terminal VG and the other end of the first resistor R1. The output terminal of the gate drive switch circuit is connected to the gate of the N-MOS transistor, and the drain of the N-MOS transistor is connected to the system power supply voltage terminal. The other input terminal of the fast turn-off circuit is connected to the other end of the first resistor R1, and the output terminal of the fast turn-off circuit is connected to the gate of the N-MOS transistor T1. The source of the N-MOS transistor T1 is used as the output terminal Vout and connected to the load. The fast shutdown circuit includes a diode D1, an inverter U2, a capacitor C1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, and an NPN transistor Q1. The positive terminal of the diode D1 is connected to the control signal terminal CON0, and the negative terminal of the diode D1 is connected to one end of the second resistor R2. The other end of the second resistor R2 is connected to one end of the capacitor C1 and the power input terminal of the inverter U2. The other end of the capacitor C1 is grounded. The other end of the first resistor R1 is connected to the input terminal of the inverter U2 and one end of the third resistor R3. The other end of the third resistor is grounded. The output terminal of the inverter U2 is connected to one end of the fourth resistor R4. The other end of the fourth resistor R4 is connected to one end of the fifth resistor R5. The other end of the fifth resistor R5 is grounded. The emitter of the NPN transistor Q1 is grounded, and the collector of the NPN transistor Q1 is connected to the gate of the N-MOS transistor T1. When the control signal at the control signal terminal CON0 changes from high level to low level, the inverter U2 continues to work due to the combined effect of the unidirectional conduction of diode D1 and the energy storage of capacitor C1. When the input terminal of inverter U2 is low level, the output terminal of inverter U2 is high level, which makes NPN transistor Q1 work and conduct, quickly discharging the gate voltage of N-MOS transistor. After the MOS is quickly turned off, capacitor C1 is discharged and inverter U2 stops working.

2. The N-MOS transistor high-side drive and fast turn-off circuit as described in claim 1, characterized in that, The gate drive switch circuit U1 includes an electronic switch K1, a sixth resistor R6, and a seventh resistor R7. One end of the electronic switch K1 is connected to the gate drive voltage terminal VG, and the other end of the electronic switch K1 is connected to one end of the seventh resistor R7. The other end of the seventh resistor R7 is connected to one end of the sixth resistor R6 and the gate of the N-MOS transistor T1. The other end of the sixth resistor R6 is grounded.

3. The N-MOS transistor high-side drive and fast turn-off circuit as described in claim 2, characterized in that, When the control signal at the control signal terminal CON0 changes from low level to high level, the gate drive switch circuit is activated, turning on the gate drive voltage terminal VG. This results in a drive voltage at the gate of N-MOS transistor T1, turning on N-MOS transistor T1 and causing the output terminal Vout of N-MOS transistor T1 to output voltage.

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