Pre-drive circuit with negative voltage protection for brushless motor driver

Abstract

The application provides a pre-driving circuit with negative pressure protection for a brushless motor driver, and relates to the technical field of electronic circuits.The pre-driving circuit comprises a power supply, a pre-driving chip, a filter circuit for filtering the power supply, an upper bridge bootstrap circuit for providing a floating power voltage for the pre-driving chip, a high-end field effect transistor, a gate of the high-end field effect transistor being connected to a high-end output of the pre-driving chip, a low-end field effect transistor, a gate of the low-end field effect transistor being connected to a low-end output of the pre-driving chip, a source of the high-end field effect transistor and a drain of the low-end field effect transistor being commonly connected to an output phase line, and an upper bridge negative electrode negative pressure embedding circuit being arranged between the output phase line and an upper bridge negative electrode of the pre-driving chip and limiting a voltage of the upper bridge negative electrode of the pre-driving chip at a fixed voltage when a voltage of the output phase line is lower than a GND voltage.The application can avoid negative pressure from entering the pre-driving chip and ensure normal work of the pre-driving chip.

Description

Technical Field

[0001] This application relates to the field of electronic circuit technology, and in particular to a pre-drive circuit for a brushless motor driver with negative voltage protection. Background Technology

[0002] The pre-drive chip of a brushless motor driver is the driver chip for IGBT / MOSFET devices in a three-phase bridge or half-bridge. Under high load conditions, the negative pin of the pre-drive chip connected to the output phase line is prone to negative voltage. The occurrence of this negative voltage can easily damage the pre-drive chip and thus damage the entire drive circuit.

[0003] To avoid the above situation, designing a circuit that can prevent negative pressure from affecting the pre-drive chip is one of the urgent problems to be solved. Utility Model Content

[0004] This application provides a pre-drive circuit for a brushless motor driver with negative pressure protection, which at least solves the above-mentioned technical problems existing in the prior art.

[0005] According to a first aspect of this application, a pre-drive circuit with negative voltage protection is provided for a brushless motor driver, comprising:

[0006] Power supply;

[0007] Pre-driver chip;

[0008] The filter circuit is set between the power supply and the power supply terminal of the pre-driver chip to filter the power supply and stabilize the power supply.

[0009] The upper bridge bootstrap circuit is connected to the upper bridge negative and upper bridge positive terminals of the pre-driver chip to provide a floating power supply voltage for the pre-driver chip.

[0010] A high-side field-effect transistor, wherein the gate of the high-side field-effect transistor is connected to the high-side output of the pre-driver chip;

[0011] The low-end field-effect transistor has its gate connected to the low-end output of the pre-driver chip, and the source of the high-end field-effect transistor and the drain of the low-end field-effect transistor are connected to the output phase line.

[0012] The upper bridge negative voltage clamping circuit is set between the output phase line and the upper bridge negative terminal of the pre-driver chip. When the voltage of the output phase line is lower than the GND voltage, it limits the voltage of the upper bridge negative terminal of the pre-driver chip to a fixed voltage.

[0013] In some embodiments of the first aspect of this application, the pre-driver chip is of model IRS21867S.

[0014] In some embodiments of the first aspect of this application, the filter circuit includes a second capacitor and a third capacitor, the first terminal of the second capacitor and the first terminal of the third capacitor are both connected to the power supply and the power supply terminal of the pre-driver chip, and the second terminal of the second capacitor and the second terminal of the third capacitor are grounded.

[0015] In some embodiments of the first aspect of this application, the upper bridge bootstrap circuit includes a first resistor, a first diode, and a first capacitor; the first resistor and the first diode are connected between the power supply terminal of the pre-driver chip and the upper bridge positive terminal, and the first capacitor is connected between the upper bridge positive terminal and the upper bridge negative terminal of the pre-driver chip.

[0016] In some embodiments of the first aspect of this application, the upper bridge negative voltage clamping circuit includes a second diode and a fourth resistor. The positive terminal of the second diode is grounded, the negative terminal of the second diode is connected to the upper bridge negative terminal of the pre-drive chip and the first end of the fourth resistor, and the second end of the fourth resistor is connected to the output phase line.

[0017] In some embodiments of the first aspect of this application, a second gate drive resistor is further included, wherein a first terminal of the second gate drive resistor is connected to the gate of the high-side field-effect transistor, and a second terminal of the second gate drive resistor is connected to the high-side output of the pre-driver chip.

[0018] In some embodiments of the first aspect of this application, a third gate discharge resistor is further included, wherein a first end of the third gate discharge resistor is connected to the gate of the high-side field-effect transistor, and a second end of the third gate discharge resistor is connected to the source of the high-side field-effect transistor.

[0019] In some embodiments of the first aspect of this application, a seventh gate drive resistor is further included, wherein a first terminal of the seventh gate drive resistor is connected to the gate of the low-end field-effect transistor, and a second terminal of the seventh gate drive resistor is connected to the low-end output of the pre-drive chip.

[0020] In some embodiments of the first aspect of this application, an eighth gate discharge resistor is further included, wherein a first terminal of the eighth gate discharge resistor is connected to the gate of the low-side field-effect transistor, and a second terminal of the eighth gate discharge resistor is connected to the source of the low-side field-effect transistor.

[0021] In some embodiments of the first aspect of this application, the source of the low-side field-effect transistor is provided with a ninth current sampling resistor to detect the phase current of the brushless motor driver.

[0022] Compared with the prior art, this application has the following advantages:

[0023] This application sets up a negative voltage clamping circuit between the output phase line and the upper bridge negative terminal of the pre-driver chip. When the voltage of the output phase line is lower than the GND voltage, the voltage of the upper bridge negative terminal of the pre-driver chip is limited to a fixed voltage, thereby preventing negative voltage from entering the pre-driver chip and ensuring the normal operation of the pre-driver chip.

[0024] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of this application, nor is it intended to limit the scope of this application. Other features of this application will become readily apparent from the following description. Attached Figure Description

[0025] The above and other objects, features, and advantages of exemplary embodiments of this application will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings. Several embodiments of this application are illustrated in the drawings by way of example and not limitation, in which:

[0026] In the accompanying drawings, the same or corresponding reference numerals indicate the same or corresponding parts.

[0027] Figure 1 The circuit block diagram of this application is shown.

[0028] Figure 2 The specific circuit diagram of this application is shown. Detailed Implementation

[0029] To make the objectives, features, and advantages of this application more apparent and understandable, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0030] Please combine Figure 1 and Figure 2 This embodiment provides a pre-drive circuit for a brushless motor driver with negative voltage protection, including:

[0031] The power supply, specifically a +15V power supply, provides positive power to the pre-driver chip.

[0032] The pre-driver chip, preferably an IRS21867S, is used to amplify the input PWM signal drive capability, improve the PWM drive current and drive voltage, and realize fast switching control of IGBT / MOSFET. TIM1_CH1 and TIM1_CH1N are the drive signal input terminals.

[0033] The filter circuit is located between the power supply and the power supply terminal of the pre-driver chip to filter the power supply and stabilize the power supply.

[0034] Specifically, the filter circuit includes a second capacitor C2 and a third capacitor C3. The first end of the second capacitor C2 and the first end of the third capacitor C3 are both connected to the +15V power supply and the power supply terminal VDD of the pre-driver chip U1. The second end of the second capacitor C2 and the second end of the third capacitor C3 are grounded to GND.

[0035] The upper bridge bootstrap circuit is connected to the upper bridge negative and upper bridge positive terminals of the pre-driver chip to provide a floating power supply voltage for the pre-driver chip.

[0036] Specifically, the bootstrap circuit includes a first resistor R1, a first diode D1, and a first capacitor C1. The first resistor R1 and the first diode D1 are connected between the power supply terminal VDD of the pre-driver chip U1 and the positive terminal VB of the bootstrap, and the first capacitor C1 is connected between the positive terminal VB of the bootstrap and the negative terminal VS of the bootstrap of the pre-driver chip U1.

[0037] High-side field-effect transistor Q1, the gate of which is connected to the high-side output HO of the pre-driver chip, and the drain of which is connected to the driver power supply VBUS, which is the power supply for the brushless motor driver.

[0038] Specifically, the high-side field-effect transistor Q1 is preferably of model BLG75T65FDL. A second gate drive resistor R2 is also included to control the gate switching speed of the high-side field-effect transistor Q1 (IGBT / MOSFET) and suppress oscillations in the gate drive signal. The first terminal of the second gate drive resistor R2 is connected to the gate of the high-side field-effect transistor Q1, and the second terminal of the second gate drive resistor R2 is connected to the high-side output HO of the pre-driver chip U1.

[0039] Additionally, a third gate discharge resistor R3 is included to quickly release the gate charge of the IGBT / MOSFET, ensuring reliable turn-off. The first terminal of the third gate discharge resistor R3 is connected to the gate of the high-side field-effect transistor Q1, and the second terminal of the third gate discharge resistor R3 is connected to the source of the high-side field-effect transistor Q1.

[0040] The low-side field-effect transistor Q2 has its gate connected to the low-side output LO of the pre-driver chip U1. The source of the high-side field-effect transistor Q1 and the drain of the low-side field-effect transistor Q2 are both connected to the output phase line OU. The output phase line OU is connected to the motor phase line. The three phase lines of the brushless DC motor need to be connected to three half-bridge circuits.

[0041] Similarly, the preferred model for the high-side field-effect transistor Q2 is BLG75T65FDL. It also includes a seventh gate drive resistor R7 to control the gate switching speed of the high-side field-effect transistor Q1 (IGBT / MOSFET). The first terminal of the seventh gate drive resistor R7 is connected to the gate of the low-side field-effect transistor Q2, and the second terminal of the seventh gate drive resistor R7 is connected to the low-side output LO of the pre-driver chip U1.

[0042] Additionally, an eighth gate discharge resistor R8 is included to quickly release the gate charge of the IGBT / MOSFET, ensuring reliable turn-off. The first terminal of the eighth gate discharge resistor R8 is connected to the gate of the low-side field-effect transistor Q2, and the second terminal of the eighth gate discharge resistor R8 is connected to the source of the low-side field-effect transistor Q2.

[0043] The upper bridge negative voltage clamping circuit is set between the output phase line OU and the upper bridge negative terminal VS of the pre-drive chip U1. When the voltage of the output phase line is lower than the GND voltage, the voltage of the upper bridge negative terminal of the pre-drive chip is limited to a fixed voltage.

[0044] Specifically, the upper bridge negative voltage clamping circuit includes a second diode D2 and a fourth resistor R4. The positive terminal of the second diode D2 is grounded, the negative terminal of the second diode D2 is connected to the upper bridge negative terminal VS of the pre-drive chip U1 and the first terminal of the fourth resistor R4, and the second terminal of the fourth resistor R4 is connected to the output phase line OU.

[0045] When the output voltage of the output phase line OU is lower than the GND voltage, D2 is turned on. Due to the unidirectional conductivity of the semiconductor, the voltage across D2 is limited to the diode's forward voltage, thus preventing negative voltage from entering pin 6 of the pre-driver chip U1, i.e., the upper bridge negative terminal VS. When the output voltage of OU is higher than GND, D2 is turned off, and the output of pin 6 of the pre-driver chip U1 is not affected, ensuring the normal operation of the pre-driver chip.

[0046] In this embodiment, the source of the low-end field-effect transistor Q2 is provided with a ninth current sampling resistor R9 to detect the phase current of the brushless motor driver.

[0047] It should be understood that the various forms of processes shown above can be used to rearrange, add, or delete steps. For example, the steps described in this application can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this application can be achieved, and this is not limited herein.

[0048] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0049] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A pre-drive circuit for a brushless motor driver with negative voltage protection, characterized in that, include: Power supply; Pre-driver chip; The filter circuit is set between the power supply and the power supply terminal of the pre-driver chip to filter the power supply and stabilize the power supply. The bootstrap circuit is connected to the negative and positive terminals of the pre-driver chip to provide power supply voltage for the pre-driver chip. A high-side field-effect transistor, wherein the gate of the high-side field-effect transistor is connected to the high-side output of the pre-driver chip; The low-end field-effect transistor has its gate connected to the low-end output of the pre-driver chip, and the source of the high-end field-effect transistor and the drain of the low-end field-effect transistor are connected to the output phase line. The upper bridge negative voltage clamping circuit is set between the output phase line and the upper bridge negative terminal of the pre-driver chip. When the voltage of the output phase line is lower than the GND voltage, it limits the voltage of the upper bridge negative terminal of the pre-driver chip to a fixed voltage.

2. The pre-drive circuit with negative voltage protection for a brushless motor driver according to claim 1, characterized in that, The pre-driver chip is model IRS21867S.

3. The pre-drive circuit with negative voltage protection for a brushless motor driver according to claim 1, characterized in that, The filter circuit includes a second capacitor and a third capacitor. The first terminal of the second capacitor and the first terminal of the third capacitor are both connected to the power supply and the power supply terminal of the pre-driver chip. The second terminal of the second capacitor and the second terminal of the third capacitor are grounded.

4. The pre-drive circuit with negative voltage protection for a brushless motor driver according to claim 1, characterized in that, The bootstrap circuit includes a first resistor, a first diode, and a first capacitor; the first resistor and the first diode are connected between the power supply terminal of the pre-driver chip and the positive terminal of the bootstrap, and the first capacitor is connected between the positive terminal of the bootstrap and the negative terminal of the bootstrap of the pre-driver chip.

5. The pre-drive circuit with negative voltage protection for a brushless motor driver according to claim 1, characterized in that, The upper bridge negative voltage clamping circuit includes a second diode and a fourth resistor. The positive terminal of the second diode is grounded, the negative terminal of the second diode is connected to the upper bridge negative terminal of the pre-drive chip and the first end of the fourth resistor, and the second end of the fourth resistor is connected to the output phase line.

6. The pre-drive circuit with negative voltage protection for a brushless motor driver according to claim 1, characterized in that, It also includes a second gate drive resistor, the first end of which is connected to the gate of the high-side field-effect transistor, and the second end of which is connected to the high-side output of the pre-drive chip.

7. A pre-drive circuit with negative voltage protection for a brushless motor driver according to claim 1 or 6, characterized in that, It also includes a third gate discharge resistor, the first end of which is connected to the gate of the high-side field-effect transistor, and the second end of which is connected to the source of the high-side field-effect transistor.

8. The pre-drive circuit with negative voltage protection for a brushless motor driver according to claim 1, characterized in that, It also includes a seventh gate drive resistor, the first end of which is connected to the gate of the low-end field-effect transistor, and the second end of which is connected to the low-end output of the pre-drive chip.

9. A pre-drive circuit with negative voltage protection for a brushless motor driver according to claim 1 or 8, characterized in that, It also includes an eighth gate discharge resistor, the first end of which is connected to the gate of the low-side field-effect transistor, and the second end of which is connected to the source of the low-side field-effect transistor.

10. The pre-drive circuit with negative voltage protection for a brushless motor driver according to claim 1, characterized in that, The source of the low-end field-effect transistor is equipped with a ninth current sampling resistor to detect the phase current of the brushless motor driver.

Images