Howto configure timer for half bridge

Roger H · ‎2018-05-06

Posted on May 06, 2018 at 14:03

Hello I am prototyping with an STM32F3xxxx and trying to figure out how to configure a timer/s to operate a half bridge smps.

The normal situation would be that there is a divide by two circuit in the block labelled 'output control' however there doesnt seem to be one in these chips, so perhaps it is not possible to drive a half bridge from a single channels two outputs ?

I can imagine perhaps you could do it with two channels but then this leads to a very dangerious and potentially transformer saturating situation when trying to change the duty cycle (as the two channels have to be changed seperatly).

Unfortunatly all the ST material seems to major on motor control and does not cover smps operation at all.

I hope someone out there has experience of this and could give me some clues please

#timer1 #d-smps #advanced-timers #smps #advanced-control-timer #half-bridge

Roger H · ‎2018-05-12

Posted on May 13, 2018 at 08:22

Woww this community is really helpfull, I am so happy I decided to design with ST!!

waclawek.jan · ‎2018-05-13

Posted on May 13, 2018 at 08:58

This forum is primarily user-driven, and apparently there are little users here with SMPS experience - I don't have that either.

If you represent a significant buying power, you may be better off asking for direct support from ST.

It appears that your question focuses on usage of timers. Generally, you want to read thoroughly the timer chapter(s) in the reference manual (RM) for your chip. I don't say it's a well-written chapter, but all the essential information is there. You maybe want to focus on the advanced timers with complementary channels; and their specifics, covered among others in the Complementary outputs and dead-time insertion subchapter. You might also perhaps want to have a look at the existing application notes on the topic ('timer cookbook').

ST offers STM32-based example SMPS designs (STEVAL-ISA147V3) so there might be related specific appnotes and examples - but as I've said, I don't know the specifics.

JW