TMS320F280039C: PMP23126 ePWM2 one-shot trip

Johnny Chen

Hi Champ,

I am asking for my customer.

I've seen below post with the same question I have it now. A follow-up question would like to ask.

https://e2e.ti.com/support/microcontrollers/c2000-microcontrollers-group/c2000/f/c2000-microcontrollers-forum/1224010/pmp23126-software-protections-and-epwm-tripzone-configuration-at-software

We do also observe the same issue that one of the ePWM2 (either Output A or B, in random ouput) cannot have one-shot trip feature and continues to generate PWM signal at its output when one-shot trip occurs on my customer's own board.

The explanation replied by the expert makes sense to me. Owing to conflicting PWMA/B actions on the same TZ event to implement PCMC and OCP / OVP.

However, when OCP / OVP one-shot trip occurs, both ePWM2 output A and B MUST be output low as customer requested, since they have damaged the switches because of one-shot trip failure.

Is there a workaround to decouple PCMC and one-shot (OCP / OVP) on ePWM2 and have ePWM2 both output A and B trip low when one-shot occurs? By using CLB for one-shot?

Thanks for the input.

Regards,

Johnny

7 months ago

0 Allison Nguyen 7 months ago

TI__Mastermind 27510 points

Hi Johnny,

You could certainly use CLB to help influence the PWM output under a specific condition. We actually have an Academy lab describing how this can be implemented: https://dev.ti.com/tirex/local?id=source_c2000_academy_labs_advanced_topics_c2000_lab_clb&packageId=C28X-ACADEMY

You could also leverage the Digital Compare submodule ".force" feature. Using the ".force" would mean that the PWM outputs are placed into a known state (e.g. low) while the digital compare condition is present. When the condition is removed, PWM activity resumes (no "clearing" of flag/status seen in the case with the trip zone OST/CBC). Let me know your thoughts on using this.

Best Regards,

Allison

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TMS320F280039C: PMP23126 ePWM2 one-shot trip