STSPIN32G4 – Unable to Drive MOSFETs

[suyog1]

Hello everyone,

I’m working on a project using the STSPIN32G4 and running into an issue where the MOSFETs are not switching as expected. I’d really appreciate some guidance from the community.

Setup:

• MCU: STSPIN32G4 (integrated STM32G4 + gate driver)

• Power stage: 3-phase inverter using N-channel MOSFETs

• Power supply: 48V

• Control method: Just attempting to drivethe Inverter

• Firmware: Own

Problem:

• The MCU is running and I can confirm firmware execution via debug.

• The MOSFETs are not turning on — no switching on the half-bridges.

• Gate driver outputs appear to stay low (no high/low drive pulses).

What I’ve Checked:

• VBOOT and VCC supply rails are within spec.

• EN/FAULT pins are pulled correctly(High).

• PWM timer configuration looks fine in CubeMX.

• Dead-time insertion is enabled.

• No over-current fault is being signaled (nFAULT pin is inactive).

Questions:

1. Are there any common setup steps (jumpers, register settings, enable sequences) I might be missing before the gate driver will actually drive the MOSFETs?

2. Do I need to explicitly enable the gate driver block via firmware before it starts responding to PWM?

3. Could the issue be related to bootstrap capacitor sizing or incorrect wiring of high-side/low-side drivers?

[GMA]

Hello @suyog1,

You can use the MCSDK tool available here to create a project with an STSPIN32G4 MCU-based board as an example.

[suyog1 · Accepted solution]

Thank you for your reply. The problem was TVS diodes. 

[GMA]

Hello @suyog1,

Thank you for your feedback.