UM2458 Inverter (SPC560P50L3 + L6491D): No Gate Drive on MOSFETs

[Jenistan]

Hello ST community,

I am working with the STM UM2458 inverter board (5 kW low-voltage, high-current inverter) using the STEVAL-CTM004V1 control board with SPC560P50L3 MCU. I am configuring the system in SPC5Studio, debugging with UDE STK, and using Motor Control Live Monitor for motor testing.

My setup:

• Supply: DC source (up to 48 V)

• Gate driver: L6491D (configured as per UM2458 schematic)

• PWM inputs: HS_IN_PWM and LS_IN_PWM are driven correctly from MCU (checked with oscilloscope)

• Bootstraps and supply voltages (+12 V, +3.3 V) are present

• Motor: small BLDC A2212/13T 1000 kV for testing

Problem:

• No switching observed at GATE_HS, SOURCE_HS, or GATE_HS outputs of the L6491D

• MOSFETs are tested OK with multimeter (no shorts)

• In Motor Control Live Monitor, I first saw “Speed feedback error” and sometimes startup errors

• After enabling open-loop FOC (parameter.h), no error is displayed but the motor does not run and MOSFETs still do not switch

Questions:

1. Why is the L6491D not producing gate drive even though PWM inputs are present?

2. Is there a recommended SPC5Studio configuration file for UM2458?

3. Do I need special settings for bootstrap charging or open-loop startup?

4. Any checklist or reference project for UM2458 with SPC560P50L3?

Thanks in advance for your support.

Best regards,

Jenistan J

[AScha.3]

Hi,

so for the driver to run : whats on its error pin , OD/SD ?

[Jenistan]

Hi,

Thanks for your response. I checked the OD/SD pin as you suggested — it is not low, I measure some voltage there.
The issue is that although I am driving the input pins (LS_IN_PWM, HS_IN_PWM), the outputs to the MOSFETs (GATE_HS, SOURCE_HS, LS) are not switching. The MOSFETs themselves are fine (I checked them with a multimeter).

So I am not sure if the problem is:

1. Configuration of the driver IC (maybe I missed a requirement for enabling it), or

2. A protection/fault condition that is preventing the outputs from switching.

Thanks for your support.

[AScha.3]

>it is not low, I measure some voltage there.

As this OD/SD pin is crucical for run or error/stop , exact voltage and check with a scope: constant and clean , or... ?

> maybe I missed a requirement for enabling it

As OD/SD pin is the only enable-or-error deciding pin.... check it !