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DRV8242-Q1: question about input PWM accuracy what device can identify/respond

Jay wang
Expert 3331 points
Part Number: DRV8242-Q1
Other Parts Discussed in Thread: DRV8424

hi experts

i want to use DRV8424 to control motor or Solenoids. from my narrow knowledge, if i want to control speed of motor accurately or control current of Solenoids accurately, i think we need to send high resolution PWM to device.

for example,  in other words, device need to identify/respond the difference between 50% and 50.1%.

Q1: what accuracy range the input PWM signal can device identify?

Q2:what parameter/spec are list in datasheet to show the ability of identify input PWM signal accuracy?

  • 0
    TI__Mastermind 45705 points

    Hi Jay,

    The minimum PWM input duty cycle (DC) will be determined by the dead-time and the slew rate SR, see page-15 of the datasheet. Assuming you have SR set fast enough the minimum DC could be close to 1 %. Once the PWM DC is above this threshold the input output circuitry is an analog circuitry, meaning whatever DC you input you will get at the output. So if you use a high resolution DC at the input you will get an high resolution DC at the output. The EVM uses 1 % resolution. You can remove the header jumper short in the EVM for PWM input and input an high res PWM and check the output for evaluation. Thanks.  

    Regards, Murugavel

  • 0 in reply to Murugavel4637
    TI__Expert 3331 points

    ok got it thanks
    i plan to apply EVM and test in the future