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STM32F334 - Peak Current Mode Control/Cycle-by-Cycle Current Limiting

Question asked by Manu Abraham on Aug 28, 2017

Hi,

 

I am trying to figure out how to go about Cycle by Cycle current limiting with the F334.

 

The current sensor output (for instance a shunt or a current transformer) is connected to the comparator non-inverting (ISENSED) input and compared against a current limit which is set on the inverting input (either a simple resistor divider or the embedded DAC if the set-point has to be adjusted dynamically). When the monitored current exceeds the current limit, the comparator output goes high and disables the PWM outputs for the remaining time in the PWM cycle. On the next cycle, if the comparator output is back to zero (i.e. the current is below the limit), the PWM output is enabled again.

 

I can input a FAULT signal FAULT2/3 on COMP4/6 non-inverting input and the reference from the DAC.

Now, that I have generated the fault signal, I am groping in the dark to BLANK each PWM pulse which caused the FAULT and restore it in the next PWM cycle

 

HELP! Trying quite hard to understand how to do this. Have been reading all available material, repeatedly.

 

If someone would be kind enough to point me in the right direction to do Cycle by Cycle current limiting with the F334, that would be very much appreciated.

 

Thanks in advance.

 

Manu

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