false trigger on break pin b12

[ahmash]

Hello experts in my solar inverter i am running pwm at 19k with break enable function polarity high ,i have pulled down breakinput pin with 1k and has not used additional circuit of lm393 yet to control break but the break function falsely trigger automaticly in above configration after few seconds and even faster if loads at outputs are high ,anyone know why it is happening ? i have also tried a 100nf capacitor parralel to 1k

[Peter BENSCH]

It will not work with an LM393 as the previous stage. If you look at its datasheet, you will see that it has an open-collector output that requires a pull-up and not a pull-down.

Regards
/Peter

[ahmash]

thanks for reply but i have not applied any ciuitary yet to the mcu brk in pin and still it triggering falsely without any signal at mcu brk pin and in resuly mcu stops pwm , where is noise coming from ?

[Peter BENSCH]

You have not yet mentioned schematics, any program or initialization, nor the exact type of the STM32. Are you using one of the Blue Pill?