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TMS320F28P650DK: Non complementary PWM signals with independent rising and falling edges using ePWM module

Alessandro N
Prodigy 30 points
Part Number: TMS320F28P650DK
Other Parts Discussed in Thread: SYSCONFIG

Tool/software:

Hi,

I would like to generate two PWM signals that in principle are independent of each other, non complementary, and with the possibility to delay their respective rising and falling edges independently.

With PWM signals that are independent of each other, I mean that I can set the cmp values where I want over the full up-counter period. This can be done with XCMP.

Then I want a rising edge delay and a falling edge delay in PWMA which are inserted with respect to the original PWMA signal. The same for PWMB.

I'm using sysconfig for the settings. However, it seems that the settings for the DeadBand Module are not able to do so as they allow to insert a deadtime between the two signals, while the Minimum DeadBand Module settings allow to insert a delay after the falling edge only in PWMB.

Do you know how to better use one or both the dead band modules (by sysconfig or by C code) to get the desired PWM signals?

I attach a picture of the desired signals:

Thank you in advance,

Alessandro

  • 0
    TI__Genius 13605 points

    Hi,

    You can use deadband submodule to add either rising edge and falling edge delay with respect to the other channel output.

    So if you could have the original pwma and original pwmb on separate pwm instances then you can use deadband submodule to add rising and falling edge delays to it wrt to each other.

    Thanks

  • 0
    Prodigy 30 points

    Hi,

    Thank you for the answer.

    Which settings or functions should I use for having the original pwma and original pwmb on separate pwm instances as you suggested for adding rising and falling edge delays wrt their original signal?

    Thank you in advance for the support,

    Alessandro

  • +1 in reply to Alessandro N
    TI__Genius 13605 points

    Hi,

    You can configure epwm1a for original a and then using deadband submodule then add rising and falling edge delay to produce pwmb with below configurations.

    What we are effectively doing with below config is the by passing db submodule for epwma and adding rising edge and falling edge delay on pwma to produce pwmb. I would not be able to write code for this config it should be straightforward from hereon.

    Thanks