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TMDSCNCD28388D: Is there any difference between using CLB generate deadband and ePWM's DB module generate deadband？

yeyuan zhu
Prodigy 70 points
Part Number: TMDSCNCD28388D

Hi,

One of my projects had a high requirement for the number of PWM outputs, which required 48 PWM outputs (complementary with dead zone). But 28388 only has 32 PWM outputs. So I came up with the idea of using 28388 CLB to generate part of the PWM output. However, due to the limited resources of CLB, I can only use the 8 modules of CLB and 8 ePWM modules to generate 32 PWM outputs( using ePWM1A and ePWM1B combined with CLB1 to generate 4-channel PWM output), so I use the DB module of ePWM to generate complementary deadband PWM outputs to meet the remaining output requirements.

I see that the clock of CLB is synchronized with the clock of PWM in TRM, but I still want to ask, could the PWM generated by these two methods be considered to be completely equivalent?

Thanks&Regards,

Zhu

  • +1
    TI__Genius 10106 points

    Hi Zhu,

    While the CLB and ePWM are clocked from the same SYSCLK, when bringing in the ePWM signals into the CLB, the ePWM signals will be considered "async." Thus, it would be recommended to enable sync input, which adds some delay to the input (typically 2 CLB CLK cycles). You would be able to achieve the same minimum deadband specification of 1 CLK cycle by using the COUNTER module within the CLB, we actually have tested something similar to this internally. You will need to account for the delay introduced from the sync input.

    Regards,

    Peter