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TMS320F28374D: PWM setting or clear output B immediately without chaning period - suggestion

Colombo Carlo
Mastermind 21560 points
Part Number: TMS320F28374D

HI eveybody ,

A PWM module has PWM_A and PWM_B outputs. Is there any way to disable (make it LOW) only PWM_B without changing duty cycle of the channel B? I see there is one option to do it by configuring AQ configurations, but it requires to update more than one registers. 

any suggestion ? can Trip zone make it ? 

best regards

Carlo

  • 0
    TI__Intellectual 1360 points

    Hi Carlo,

    Is the above waveform what you want ? Can you elaborate some more on your requirements. For example when would the PWMB be forced low, Do you expect it to come back after s few PWM cycles etc. Based on your requirements, we can explore the possible options.

    Regards,

    Srinivasa

  • 0 in reply to Srinivasa Chakravarthy
    Prodigy 60 points

    Hi Srinivasa,

    Let me elaborate. 

    • PWM module uses complementary mode by using dead-band submodule.
    • Is there any submodule to control either make only one output PWM A or PWM B to LOW/HIGH without affecting the other output?
      • For example, PWM B output is complementary from the DB submodule. PWM A and PWM B outputs complementary pulses with 50% duty cycle. Now PWM A need to be LOW without making PWM B HIGH. PWM B should output the same 50% duty cycle pulses. 

    Is there any gating logic or making HIGH/LOW to control PWM A/B after DB?

    Thanks,

    Justin

  • 0 in reply to Justin Ryu1
    TI__Guru 51940 points

    After the DEADBAND module you have three options I can think of.

    1. TripZone: TZFRC

    2. CLB: This can 100 get the job done with additional custom logic. A simple design would be gating the Deadband module with an AND gate and SW control gate signal.

    3. GPIO Mux: Switch GPIO mux to point to GPIO instead of EPWMB. The GPIO is in Output/HIGH mode.