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Can CBC trip event be cleared before period is over?

andreas von kaenel
Genius 4925 points

Hi all,

Before I lose a lot of time by setting up a test, I post my question here:
                             ________________                 
PWM Period  ________________|                |________________|
            ______          ___________________________________
trip input        |________|
                   ____________
EPWM output ______|            ???????????????________________|
                                _
TZCRL       ___________________| |_____________________________

What happens to the EPWM output, that has been correctly tripped by a trip-event, when I clear the tripflag before the period is over. Will the ouput fall to 0 (assumed there is no other event active), or doesn't happen anything until the period is crossed??

BR Andreas

  • 0
    Genius 5170 points

    As far as I can remember ... in case of CBC ... the PWM output will remain in trip state until the beginning of the next cycle. I believe there have been few requests to provide a mode where PWM output will start operating normally when the trip event is cleared ... I am not sure if that feature is incorporated in any C2000 devices or not ...

  • 0 in reply to Arefeen
    Genius 4925 points

    Arefeen,

    Thanks for your reply, I interrept the datasheet the same way you do, although I would like to find a specific timing diagram for these cases ... :-)

    Arefeen Mohammed said:

    I believe there have been few requests to provide a mode where PWM output will start operating normally when the trip event is cleared ... I am not sure if that feature is incorporated in any C2000 devices or not ...

    TI Guru's, can you give a feedback about this point - that would exaclty be the thing to make my life easier...

    BR Andreas

  • 0 in reply to andreas von kaenel
    TI__Genius 10820 points

    Andreas,

    Arefeen is correct about the CBC mode of operation. In the CBC mode, even if you clear the CBC flag, the PWM output will stay in its 'tripped' state till the end of the current PWM cycle. If you have an INT generated from the CBC event another INT can be generated if a trip event occurs again within that current PWM cycle after clearing the CBC flag.

    When operating in one-shot trip mode (OST), as soon as the OST flag is cleared the PWM output will go to a state dictated by the PWM signal feeding into the trip zone sub-module. This PWM signal is the one coming from the previous sub-modules in the signal chain (Action qualifier, Dead band, PWM chopper). That is to say, as soon as the OST event is cleared the PWM output will function normally as it does when there is no trip event.

    I hope this helps.

    - Hrishi