TMS320F28379D: How to make EPW1A and EPWM1B low simultaneously

Hi Hridya,

Can you please elaborate on how you make the signals complementary, is this through the action qualifier submodule or through the deadband submodule?

I would suggest looking at the AQSFRC register. You can invoke a one-time software force that forces the EPWM outputs to a certain state. 

Best Regards,

Marlyn

It is through the dead band module that i am making complementary signals. But i would like to make both PWMs 0 say in the negative half of the modulating signal. Currently, with complementary PWMs, if channel A is '0', I see channel B '1'. How to make both 0?

Hi Hridya

For x49c MCU DBCTL=0x000B mode 4 should make AH symmetrical EPWM-A/B both low/high depending DB gens S4,S5,S8 binary, see x79D TRM figures for correct switches. The inversion to make AH complementary pairs mode 2 (x49c) are S2,S3,S4,S5,S8 binary values, perhaps the same switches x79D?  

Hi Hridya,

You do not need to wait for a fault/trip event in order to utilize the trip zone submodule. You could force a trip condition using the TZFRC register. Select the force action on PWM output A/B to be low in TZCTL.

Best Regards,

Marlyn

Thank you Marlyn Rosales Castaneda20 , so u mean to say when I detect that the modulation  signal is going in negative direction, make the TZCTL.bit.TZA and TZCTL.bit.TZB =0..Right?

Hridya I said:

(not just during fault/trip but during normal operation)

That would seem to require SW control of dead band module switches during that time or perhaps SW change of CMPA match count direction shadow register. Personally I'd try to achieve desired symmetrical inversion via dead band generators first. We use dynamic real time SW control of RED/FED in another TI MCU works great. 

Hi Hridya,

Yes, one way to implement this is to force a trip zone event through the TZFRC register and then configuring the TZA and TZB bits of the TZCTL register to make the respective outputs low. Once the modulating signal is no longer negative you can clear the trip zone signal.

Best Regards,
Marlyn

Sure Marlyn Rosales Castaneda20, will test and keep updated

Also have a look at TRM Fig.18-34 Active Low dead band pairs.