How to drive the BOOT pins of a STSPIN32F0251?

[MLamp.2]

I have an EVSPIN32F02Q1S1 board to experiment. Each boot pin has a connection to Vcc via a diode (D1, D4, D7) - which are not mounted on the board. When driving a phase full on the pull up MOSFET breaks down about every 2.5ms. The time varies depending on other IO signals.

I can not find a reference data sheet or application note about the MOSFET driver circuitry of this chip.

Anybody knows how to drive this pin?

If I need 100% Vcc output, is populating those diodes all that is required?

What are the implications?

[Peter BENSCH · Accepted solution]

The driver works like all known half-bridge drivers based on bootstrap capacitors and is comparable to the STDRIVE101, but can work with a higher bridge voltage. The evaluation board offers the option of connecting external bootstrap diodes to reduce the time to charge the bootstrap capacitors.

100% VCC output is only possible for the (limited) time that the bootstrap capacitors supply the high-side FET and remain above the UVLO limit.

Regards

/Peter

[MLamp.2]

Thanks Peter, the datasheet for the STDRIVE101 has all the answers. Might be worth adding a reference to the STSPIN32F0251 datasheet.

Markus