TZA & TZB and dead band

dreja

Hello,

I'm using the microcontroller TMS320F28062PZPS.

My PWM module is configured to use the dead band between EpwmA and EpwmB signals.

EPwmRegs->DBCTL.bit.IN_MODE = DBA_RED_DBB_FED; /*EpwmA = rising edge, EpwmB = falling edge surce*/
EPwmRegs->DBCTL.bit.OUT_MODE = DB_FULL_ENABLE;

EPwmRegs->DBCTL.bit.POLSEL = DB_ACTV_HIC;

EPwmRegs->DBFED = dead_time;
EPwmRegs->DBRED = dead_time;

For current limit function I use the TZA and TZB events with the following actions:

EPwm1Regs.TZCTL.bit.TZA = TZ_FORCE_LO;
EPwm1Regs.TZCTL.bit.TZB = TZ_FORCE_HI;

My issue is, that in case of current limit (TZA and TZB), the Epwm1A and Epwm1B outputs are switched off and on immediately: With no "dead time" between them.

Is there any possibility to use the dead time also in case, when the PWM outputs are forced with TZA and TZB commands ?

Thank you and best regards

Andrej

over 9 years ago

0 Fulano de Tal over 9 years ago

Expert 2090 points

The TZ submodule ignores any deadbands set DBFED/DBRED. I had to deal with the same issue. The easiest thing for me to do was set TZA and TZB to do nothing, and then handle forcing PWMs low/high in a TZ interrupt. You can use a delay in the TZ interrupt, or modify CMPA/CMPB with a the correct amount and let it finish the PWM cycle.

0 dreja over 9 years ago in reply to Fulano de Tal

Intellectual 350 points

Thank you for your answer.
I will try to do as you suggest.
Andrej

C2000™︎ microcontrollers

C2000 microcontrollers forum

TZA & TZB and dead band