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DRV8703-Q1: VM pin power-on recommendation

Viktorija Cecil
Mastermind 18491 points
Part Number: DRV8703-Q1

In customers design “VM” pin is only powered some of the time (they only turn on VM when they generate a command to move the motor). Is there any issue with this or is VM recommended to be powered all the time?

  • 0
    TI__Prodigy 460 points

    Hi Viktorija, 

    Yes, it is okay to power VM some of the time. If VM falls below the under voltage lockout (Vuvlo2) the H-bridges are disabled, the charge pump is disabled, and nfault is driven low. Everything resumes normal operation, when VM rises above the under voltage lockout (Vuvlo2). 

    One additional recommendation is to set the inputs to a logic low when VM = 0. This will remove any current flowing through the internal pulldown resistors.

    Thanks, 

    Madison Eaker

    Motor Drivers

  • 0 in reply to Madison Eaker
    TI__Mastermind 18491 points

    Thanks.

    Is there a recommended power up sequence that TI recommends for this driver before issuing a PWM command to move? For example, how long should VM be active until we start to PWM?

  • 0 in reply to Viktorija Cecil
    TI__Prodigy 460 points

    Hi Viktorija,

    There is no required sequence. The device will not begin driving until VM voltage is above Vuvlo2 recovery ~5.4V. The system may want to hold off until VM is higher than 5.4V. 

     Thanks, 

    Madison Eaker

    Motor Drivers