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STM32H753 HRTIM for BLDC control with complementary outputs

Linas L
Senior II

In my project I need to have ~25KHz high resolution PWM generation. So for this I selected STM32H753 with 480MHz HRTIM1.

I am struggling producing correct outputs for my needs, maybe some one has this done already and care to share the project ? Problems I am facing:

  • 3 channels of synchronized PWM outputs with complimentary part (and dead-time)
  • ADC trigger in correct spot for 3 channels, so I could see if any phase is shorted

Ok, so the first problem I don't know how to deal with.  it looks like HRTIM1 does actually have one master timer and many other timers with it's own period counters. In order to synchronize PWM outputs, it looks like I need to use master timer for it somehow. It does have many compare units also a period counter. what is correct way of generating simple 3 channels of synchronized PWMs? (why where are no example for this task, it looks it should me main example in my mind...)

Can I simply use compare units on master timer and TX1 and TX2 would just add dead time ? or i need to set master timer period lower and start each timer in one "single shot mode" with pulse with selected in CCR register ?

Second problem is how to properly align ADC sample points on each phase. Problem I face is that I routed  current sence to pins, that are only ADC1/2. Does this mean I can't have perfect sample point on each phase, and best I can do is selecting lowest PWM width middle point for current measurement ?

Looking forward for ideas, and in the mean time, going to read RM and see how it goes