• State Resolved
  • Locked Locked
  • Replies 2 replies
  • Subscribers 82 subscribers
  • Views 533 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TMS320F280025C: PWM Trip settings ???

david goodin
Intellectual 410 points

Part Number: TMS320F280025C
Other Parts Discussed in Thread: C2000WARE

Greetings all, 

I am trying to find a good sample of setting up a PWM trip function. 

I want to Use CMPSS4 "high" to trip PWM3 (both A and B channels) when the analog signal going in to CMPSS4 exceeds the DtoA value on the comparator.

I'd like it to be a "cycle by cycle" trip (current limiting function) and have PWM enabled at the beginning of each PWM Period. 

I have the CMPSS4 fed by the input pin 22 as called out in the analog pin mux.

PWM XBAR trip input is set to trip4 Mux6 set to CMPSS4 CTRIPH.

PWM trip zone action DCAEVT2 and DCBEVT2 are set to  "low voltage state".

I've tried a bunch of different combinations for the rest of the DCAEVTx and DCBEVTx settings but the technical reference manual doesn't make a lot of sense in this realm. So, after spending 20 hours on this, I figured I'd just ask. 

Anyone know the magic settings to get this to work?

  • 0
    TI__Genius 11076 points

    Hello David,

    Let me ask a couple clarifying questions. You're trying to configure DCxEVTx to cause a cycle-by-cycle trip forcing the both channels of ePWM3 low when the event triggers, yes? What does your output currently look like- no trip occurring? If so, can you show me what the configuration for the TZ looks like in your registers?

    Finally, have you had a chance to check out the ePWM trip zone examples in C2000Ware? They were a huge boon for me when I was first learning to understand how the ePWM works, along with the associated section of C2000 Academy!

    Regards,

    Jason Osborn

  • 0 in reply to Jason Osborn
    Intellectual 410 points

    Thanks Jason, 

    I re-read^5 the PWM example in the PWM manual and finally figured out what I was missing. Now, the PWM kicks off when the input voltage goes higher than the reference DtoA on the CMPSS comparator. 

    Now, I just need to figure out how to turn the PWM back on after a short "off" time. Making a constant off time current "chopper".