High-side bootstrap gate drive circuit applied to half-bridge topology

Abstract

The utility model provides a high-side bootstrap gate driving circuit applied to half-bridge topology, which belongs to the technical field of motor driving and specifically comprises a gate driver circuit, a half-bridge circuit and a high-side driving continuous power supply module. A high-side gate driving signal pin HO, a low-side gate driving signal pin LO and a high-side floating power supply backflow pin VS of the gate driver circuit are electrically connected to the half-bridge circuit, and the high-side driving continuous power supply module is electrically connected with the gate driver circuit. And the high-side driving continuous power supply module is used for continuously supplying power to a high-side driving output pin HO when the high-side driving output pin HO of the gate driver circuit needs to output a high level. According to the processing scheme, compared with an isolated power supply mode, the use amount of devices is small, the purpose that the half-bridge circuit can still use the bootstrap gate drive circuit when the PWM duty ratio changes greatly or the frequency is too high can be achieved, and the processing scheme has engineering use value.

Description

Technical Field

[0001] The present application relates to the field of motor drives, and in particular, to a high-side bootstrap gate drive circuit applied to a half-bridge topology. Background Art

[0002] A motor driver is a power conversion device widely used in fields such as industrial automation equipment and military equipment, and has the characteristics of high frequency, high efficiency, and small size. In order to improve the output efficiency and accelerate the motor speed regulation speed, a full-bridge or three-phase bridge drive circuit is often used. Whether it is a full-bridge or three-phase bridge drive circuit, it is composed of a half-bridge topology. The high-side MOS transistor in the half-bridge topology needs the gate voltage to be 10-15V higher than the source voltage to conduct. However, the source potential of the high-side MOS changes floatingly relative to GND with the switching of the MOS transistor. Therefore, it is required that the gate potential of the high-side MOS also changes floatingly following the source. The power supply of the gate drive circuit generally comes from a separate isolated power supply or adopts a bootstrap circuit. The isolated power supply has the problems of high cost and large volume. With the trend of the motor driver becoming increasingly miniaturized, lightweight, and low-cost, in the field of low-voltage motor drivers, a bootstrap circuit is often adopted. The bootstrap circuit has the advantages of simple structure and few components. The power supply principle of the bootstrap circuit is as follows: in the half-bridge topology, after the low-side MOS transistor conducts, the power supply forms a capacitor charging loop through the bootstrap diode, the bootstrap capacitor, and the low-side MOS transistor to charge the bootstrap capacitor. After the bootstrap capacitor is fully charged, it is about 10-15V higher than the source of the high-side MOS (depending on the power supply voltage and the diode conduction voltage drop), and then the bootstrap capacitor supplies power to the high-side gate drive circuit. However, the bootstrap circuit is limited by the refresh charge time of the bootstrap capacitor. When the PWM duty cycle changes within a large range or the frequency is too high, there is a problem that the charging time of the bootstrap capacitor is insufficient, resulting in abnormal operation of the upper bridge arm gate drive. Summary of the Utility Model

[0003] In view of this, the present application provides a high-side bootstrap gate drive circuit applied to a half-bridge topology, which solves the problems in the prior art and achieves the purpose of using fewer device components compared with the isolated power supply method and enabling the half-bridge circuit to still use the bootstrap gate drive circuit when the PWM duty cycle changes greatly or the frequency is too high.

[0004] The high-side bootstrap gate drive circuit applied to a half-bridge topology provided by the present application adopts the following technical solutions:

[0005] A high-side bootstrap gate drive circuit applied to a half-bridge topology, comprising a gate driver circuit, a half-bridge circuit, and a high-side drive continuous power supply module. The high-side gate drive signal pin HO, the low-side gate drive signal pin LO, and the high-side floating power return pin VS of the gate driver circuit are electrically connected to the half-bridge circuit. The high-side drive continuous power supply module is electrically connected to the gate driver circuit. The high-side drive continuous power supply module is used to continuously supply power to the high-side drive output pin HO when the high-side drive output pin HO of the gate driver circuit needs to output a high level.

[0006] Optionally, the gate drive circuit includes a gate drive chip U1, a power filter capacitor C1, a bootstrap diode V1, and a bootstrap capacitor C2. The power filter capacitor C1, the bootstrap diode V1, and the bootstrap capacitor C2 are all electrically connected to the gate drive chip U1.

[0007] Optionally, the half-bridge circuit includes a gate drive resistor R4, a gate drive resistor R5, a gate charge discharge resistor R6, a gate charge discharge resistor R7, an MOS transistor Q1, and an MOS transistor Q2. One end of the gate drive resistor R4 and one end of the gate charge discharge resistor R6 are electrically connected to the gate of the MOS transistor Q1. The gate drive resistor R5 and the gate charge discharge resistor R7 are electrically connected to the gate of the MOS transistor Q2. The drain of the MOS transistor Q1 and the source of the MOS transistor Q2 are electrically connected. The source of the MOS transistor Q1 is connected to the main power supply VIN. The drain of the MOS transistor Q2 is grounded to GND. The other end of the gate charge discharge resistor R6 is electrically connected to the high-side floating power return pin VS of the gate drive chip U1. The other end of the gate charge discharge resistor R7 is connected to the drain of the MOS transistor Q2. The gate drive resistor R4 is electrically connected to the high-side gate drive signal pin HO of the gate drive chip U1. The gate drive resistor R5 is electrically connected to the low-side gate drive signal pin LO of the gate drive chip U1.

[0008] Optionally, the high-side drive continuous power supply module is a square wave generating circuit. The square wave generating circuit includes a timer chip U2, a boost capacitor C3, a vibration capacitor C4, a decoupling capacitor C5, an oscillation resistor R1, a pull-up resistor R2, a current limiting resistor R3, a zener diode VZ1, a diode V2, and a diode V3. The high-side floating power return pin VS of the gate drive chip U1 is connected to the external power supply pin VDD of the timer chip U2. The high-side floating power input pin VB of the gate drive chip U1 is electrically connected to the external power supply pin VDD of the timer chip U2 through the series-connected diodes V2 and V3.

[0009] When the MOS transistor Q1 is turned on and the MOS transistor Q2 is turned off, the main power supply VIN forms a loop through the MOS transistor Q1, the voltage stabilizing diode VZ1, and the current limiting resistor R3. The loop charges the capacitor C5, generating a first voltage with the reference point being the high-side floating power return pin VS. The voltage will start the timer chip U2 to work. After being processed by the boost capacitor C3, the diode V2, and the diode V3 through the output pin OUT of the timer chip U2, it is converted into a second voltage and sent to the high-side floating power input pin VB of the SLM2184S to charge the bootstrap capacitor C2.

[0010] Optionally, the timer chip U2 is a 555 timer.

[0011] Optionally, the gate driver chip U1 is an SLM2184S.

[0012] In summary, the present application includes the following beneficial technical effects:

[0013] Through the high-side bootstrap gate drive circuit high-side drive continuous power supply module, the bootstrap capacitor charging circuit of the present application is no longer affected by the frequency and duty cycle of the PWM drive circuit. The circuit topology of the present application is simple, the device usage is less compared to the isolated power supply method, and it can achieve the purpose that the bootstrap gate drive circuit can still be used when the PWM duty cycle changes greatly or the frequency is too high in the half-bridge circuit, and it has engineering application value. Description of the Drawings

[0014] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0015] Figure 1 It is the schematic diagram of the high-side bootstrap gate drive circuit applied to the half-bridge topology of the present application. Detailed Embodiments

[0016] The following will describe the embodiments of the present application in detail with reference to the drawings.

[0017] The following describes the implementation manners of the present application through specific specific examples. Those skilled in the art can easily understand other advantages and effects of the present application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, without conflict, the following embodiments and the features in the embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope protected by the present application.

[0018] It should be noted that the following describes various aspects of the embodiments within the scope of the appended claims. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is illustrative only. Based on the present application, those skilled in the art should understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects described herein can be used to implement the device and / or practice the method. Additionally, this device and / or method can be implemented using other structures and / or functionality in addition to one or more of the aspects described herein.

[0019] It should also be noted that the diagrams provided in the following embodiments only illustrate the basic concept of the present application in a schematic manner. The diagrams only show the components related to the present application and are not drawn according to the number, shape, and size of the components in actual implementation. The type, quantity, and ratio of each component in its actual implementation can be an arbitrary change, and the component layout type may also be more complex.

[0020] In addition, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that the described aspects can be practiced without these specific details.

[0021] The embodiment of the present application provides a high-side bootstrap gate drive circuit applied to a half-bridge topology.

[0022] As Figure 1As shown in the figure, a high-side bootstrap gate drive circuit applied to a half-bridge topology includes a gate driver circuit, a half-bridge circuit, and a high-side drive continuous power supply module. The high-side gate drive signal pin HO, the low-side gate drive signal pin LO, and the high-side floating power supply return pin VS of the gate driver circuit are electrically connected to the half-bridge circuit. The high-side drive continuous power supply module is electrically connected to the gate driver circuit. The high-side drive continuous power supply module is used to continuously supply power to the high-side drive output pin HO when the high-side drive output pin HO of the gate driver circuit needs to output a high level.

[0023] The gate drive circuit includes a gate drive chip U1, a power filter capacitor C1, a bootstrap diode V1, and a bootstrap capacitor C2. The power filter capacitor C1, the bootstrap diode V1, and the bootstrap capacitor C2 are all electrically connected to the gate drive chip U1.

[0024] The high-side drive continuous power supply module of the high-side bootstrap gate drive circuit of the present application makes the bootstrap capacitor charging circuit no longer affected by the frequency and duty cycle of the PWM drive circuit.

[0025] The half-bridge circuit includes a gate drive resistor R4, a gate drive resistor R5, a gate charge discharge resistor R6, a gate charge discharge resistor R7, a MOS transistor Q1, and a MOS transistor Q2. One end of the gate drive resistor R4 and one end of the gate charge discharge resistor R6 are electrically connected to the gate of the MOS transistor Q1. The gate drive resistor R5 and the gate charge discharge resistor R7 are electrically connected to the gate of the MOS transistor Q2. The drain of the MOS transistor Q1 and the source of the MOS transistor Q2 are electrically connected. The source of the MOS transistor Q1 is connected to the main power supply VIN. The drain of the MOS transistor Q2 is grounded to GND. The other end of the gate charge discharge resistor R6 is electrically connected to the high-side floating power supply return pin VS of the gate drive chip U1. The other end of the gate charge discharge resistor R7 is connected to the drain of the MOS transistor Q2. The gate drive resistor R4 is electrically connected to the high-side gate drive signal pin HO of the gate drive chip U1. The gate drive resistor R5 is electrically connected to the low-side gate drive signal pin LO of the gate drive chip U1.

[0026] The high-side drive continuous power supply module is a square wave generating circuit. The square wave generating circuit includes a timer chip U2, a boost capacitor C3, a vibration capacitor C4, a decoupling capacitor C5, an oscillation resistor R1, a pull-up resistor R2, a current limiting resistor R3, a voltage stabilizing diode VZ1, a diode V2, and a diode V3. The high-side floating power supply return pin VS of the gate drive chip U1 is connected to the external power supply pin VDD of the timer chip U2. The high-side floating power input pin VB of the gate drive chip U1 is electrically connected to the external power supply pin VDD of the timer chip U2 through the series-connected diodes V2 and V3.

[0027] When MOS transistor Q1 is turned on and MOS transistor Q2 is turned off, the main power supply VIN forms a loop through MOS transistor Q1, zener diode VZ1, and current-limiting resistor R3. The loop charges capacitor C5, generating a first voltage with the high-side floating power supply return pin VS as the reference point. The voltage will start the operation of timer chip U2. After being processed by boost capacitor C3, diode V2, and diode V3 through the output pin OUT of timer chip U2, it is converted into a second voltage and sent to the high-side floating power supply input pin VB of SLM2184S to charge bootstrap capacitor C2.

[0028] In this application, when MOS transistor Q1 is turned off and MOS transistor Q2 is turned on, the auxiliary power supply VCC charges bootstrap capacitor C2 through diode V1; when MOS transistor Q1 is turned on and MOS transistor Q2 is turned off, the main power supply VIN forms a loop through MOS transistor Q1, zener diode VZ1, and current-limiting resistor R3. The loop charges capacitor C5, generating a -15V voltage with the high-side floating power supply return pin VS as the reference point, and starts the operation of 555 timer U2. When working, the OUT pin of U2 outputs a 15V square wave signal with a certain frequency. After being processed by boost capacitor C3, diode V2, and diode V3, the 15V square wave signal is converted into a 15V voltage to charge bootstrap capacitor C2, so as to achieve the purpose that the bootstrap gate drive circuit can still be used when the PWM duty cycle of the half-bridge circuit changes greatly or the frequency is too high.

[0029] The timer chip U2 is a 555 timer.

[0030] The circuit topology of this application is simple. Compared with the isolated power supply feeding method, the number of components used is less. It can achieve the purpose that the bootstrap gate drive circuit can still be used when the PWM duty cycle of the half-bridge circuit changes greatly or the frequency is too high, and has engineering application value.

[0031] The above is only the specific implementation manner of this application, but the protection scope of this application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed in this application should be covered by the protection scope of this application. Therefore, the protection scope of this application should be subject to the protection scope of the claims.

Claims

1. A high-side bootstrap gate drive circuit applied to a half-bridge topology, characterized in that, It includes a gate driver circuit, a half-bridge circuit, and a high-side drive continuous power supply module. The high-side gate drive signal pin HO, the low-side gate drive signal pin LO, and the high-side floating power supply return pin VS of the gate driver circuit are electrically connected to the half-bridge circuit. The high-side drive continuous power supply module is electrically connected to the gate driver circuit. The high-side drive continuous power supply module is used to continuously supply power to the high-side drive output pin HO when the high-side drive output pin HO of the gate driver circuit needs to output a high level.

2. The high-side bootstrap gate drive circuit applied to a half-bridge topology according to claim 1, wherein The gate drive circuit includes a gate drive chip U1, a power filter capacitor C1, a bootstrap diode V1, and a bootstrap capacitor C2. The power filter capacitor C1, the bootstrap diode V1, and the bootstrap capacitor C2 are all electrically connected to the gate drive chip U1.

3. The high-side bootstrap gate drive circuit applied to a half-bridge topology according to claim 2, wherein The half-bridge circuit includes a gate drive resistor R4, a gate drive resistor R5, a gate charge discharge resistor R6, a gate charge discharge resistor R7, a MOS transistor Q1, and a MOS transistor Q2. One end of the gate drive resistor R4 and one end of the gate charge discharge resistor R6 are electrically connected to the gate of the MOS transistor Q1. The gate drive resistor R5 and the gate charge discharge resistor R7 are electrically connected to the gate of the MOS transistor Q2. The drain of the MOS transistor Q1 and the source of the MOS transistor Q2 are electrically connected. The source of the MOS transistor Q1 is connected to the main power supply VIN. The drain of the MOS transistor Q2 is grounded to GND. The other end of the gate charge discharge resistor R6 is electrically connected to the high-side floating power supply return pin VS of the gate drive chip U1. The other end of the gate charge discharge resistor R7 is connected to the drain of the MOS transistor Q2. The gate drive resistor R4 is electrically connected to the high-side gate drive signal pin HO of the gate drive chip U1. The gate drive resistor R5 is electrically connected to the low-side gate drive signal pin LO of the gate drive chip U1.

4. The high-side bootstrap gate driving circuit applied to a half-bridge topology according to claim 3, wherein The high-side drive continuous power supply module is a square wave generating circuit. The square wave generating circuit includes a timer chip U2, a boost capacitor C3, a vibration capacitor C4, a decoupling capacitor C5, an oscillation resistor R1, a pull-up resistor R2, a current limiting resistor R3, a zener diode VZ1, a diode V2, and a diode V3. The high-side floating power supply return pin VS of the gate drive chip U1 is connected to the external power supply pin VDD of the timer chip U2. The high-side floating power input pin VB of the gate drive chip U1 is electrically connected to the external power supply pin VDD of the timer chip U2 through the series-connected diodes V2 and V3. When the MOS transistor Q1 is turned on and the MOS transistor Q2 is turned off, the main power supply VIN forms a loop through the MOS transistor Q1, the zener diode VZ1, and the current limiting resistor R3. The loop charges the capacitor C5 to generate a first voltage with the high-side floating power supply return pin VS as the reference point. The voltage will start the timer chip U2 to work. The output voltage of the timer chip U2 is processed by the boost capacitor C3 and the diodes V2 and V3 and then converted into a second voltage to the high-side floating power input pin VB of the SLM2184S to charge the bootstrap capacitor C2.

5. The high-side bootstrap gate driving circuit applied to a half-bridge topology according to claim 4, characterized in that, The timer chip U2 is a 555 timer.

6. The high-side bootstrap gate driving circuit applied to a half-bridge topology according to claim 2, wherein The gate driver chip U1 is SLM2184S.

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