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DRV8353RS-EVM: 3x PWM Mode can have synchronous PWM ? what is diff. b/w 6x PWM and independent mode.

mitesh vishwakarma
Prodigy 10 points
Part Number: DRV8353RS-EVM

Hello,

I am trying to use 3xPWM Mode and 6x PWM Mode, for sensor-ed sinusoidal commutation.
As mentioned into datasheet i have connected 3 of INHX for high side half bridge switching and expecting to generate synchronous PWM from DRV, but DRV is unable to generate complimentary PWM for LOW side half bridge.
If 3x PWM means not to generate synchronous PWM then what does it mean for ? does INLX pin remain hi-z state in that case ?

For 6x PWM Mode does it will work individual for high side half bridge and low side half bridge?
and if yes then what is mean by Independent PWM Mode ? how it can be different from 6x PWM Mode?

  • 0
    TI__Mastermind 19630 points

    Hello Mitesh,

    Thank you for your question, I am not sure I understand the questions completely so feel free to let me know if I missed anything. 3x PWM is used to decrease the amount of signals needed in order to drive a motor. In your setup how was your INLx pin configured? For 3xPWM the INLx pin is used to control the high impedance (High-Z) state of the current sense input but will also keep both GLx and GHx low if INLx pin is low. The truth table can be found on page 30 of the data sheet. Since you are using sinusoidal control you might want to pull INLx high, since all phases are driving current for sinusoidal control.

    Entering a 0 or logic low value for INHx will generate a high value for GLx, low value for GHx.

    Entering a 1 or logic high value for INHx will generate a low value for GLx, high value for GHx.

    For 6x PWM mode it also follows a truth table, so the input PWM will not generate an output that matches the PWM that was entered but instead follow the truth tables logic. For example, being where both INLx and INHx are high logic level inputs then both GLx and GHx will be low. That is essentially the main difference between 6x PWM and independent. In independent mode the input PWM will match the output PWM signal. The truth table can be seen below for independent mode:

    Best,

    Isaac

  • 0 in reply to Isaac Lara
    TI__Mastermind 21805 points

    Hello Mitesh,

    Do you need further assistance on this thread?

    Thanks,

    Matt

  • 0 in reply to Matt Hein
    TI__Mastermind 21805 points

    Hi Mitesh,

    I'm going to go ahead and close this thread. If you have further questions, please click the "Ask a related question" button.

    Thanks,

    Matt