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TMS320F28033: PWM output after Power drop

Emma Wang
Expert 5390 points

Part Number: TMS320F28033

Hi expert,

I have a customer want to test power drop down situation.

So they turn down the power from 3.3V to 2.8V.

I know the it is already lower than our recommended voltage. 

At about 2.8V, the DSP will crash, and the output level of the EPWM port of the DSP will change from high to low. and they hope to the PWM turn low quickly

During this process, the Vgs of the PFC_MOS tube continues to be high for about 600us. 

Green- C2000 PWM, blue - Vgs

They want to know the default state of the EPWM design after the chip power supply is abnormal/crash,

and whether the 600us period is mainly related to the internal circuit of the chip EPWM. 

BR

Emma

  • 0
    TI__Mastermind 42195 points

    Emma,

    If you hold the device outside of our recommended operating conditions its difficult to say what would happen to the PWM output. Now if the BOR is activated then the pin should enter a 'reset' state.

    Can you confirm what is connected to the PWM pin are there any pull-up resistors?

    Which pin is showing this behavior? Some pins have a weak pull-up enabled by default.

    Can you observe XRSn such that we can see when and if a BOR occurred?

    Regards,
    Cody