We are using EVSPIN32F0251S1 Motor Control board. We are able to drive the lower mosfets on the board , however we are not able to drive the higher side mosfets.

[PShah.4]

We think the firmware configuration is correct because we tested the same code on STM32F0 discovery board and PWM gets generated on all the 6 pins which are used in the EVSPIN32F0251S1 board.

So code is not issue.

Can anyone explain what can be the actual problem ?

[Cristiana SCARAMEL]

Hello @PShah.4​ and welcome to the ST Community.

The high-side section is supplied by a bootstrapped voltage technique with integrated bootstrap diode.

At the power-up, there may be no charge in the bootstrap capacitors. In this case, the driver cannot start immediately with normal operation, but the bootstrap capacitor should be charged turning on the low-side MOSFET.

The charging time of the bootstrap capacitors depends on their value but also on the resistance of the bootstrap diode (RDboot), which limits the current flow.

In your firmware, at the power-up is there enough time to load the bootstrap capacitors?

[Cristiana SCARAMEL]

Hello @PShah.4​ is there feedback from you?

[PShah.4]

Hello @Cristiana SCARAMEL​ , I am extremely sorry for the late reply.

Due to some unavoidable circumstances, we have not tested this solution. We are going to test the solution on coming Saturday. Will update you accordingly