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DRV120: DRV120

Jan Volkering
Expert 8190 points
Part Number: DRV120

A customer I support is looking for a driver that can drive solenoids from 5 to 24V @ 100mA (200mA current limit).

Since the DRV120 is an open drain driver, is it OK to power the device itself from a voltage rail that is within the datasheet specs (6V-26V) and have the solenoid connected between a 5V - 24V supply and the open drain output?

If the customer does not want to use the hold current option, can he connect the KEEP pin to ground, thereby keeping the device operating on the peak current setting?  Is then the PWM dutycycle 100% (continuous ON)?

I assume that the PWM operation only kicks in when the HOLD mode is active , PWM dutycycle determined by the R-hold setting?  Pls. comment.

  • 0
    TI__Expert 6330 points
    Hi Jan,

    Allow me to contact the engineer in charge of these products. Expect a reply by 3/7/18 at the latest.

    Regards,
    Aaron
  • 0
    TI__Intellectual 1965 points

    Hi Jan,

    The voltage at the input pin and the voltage at the solenoid can be different as long as they are within the recommended operating range of 6V to 26V. The only issue you may have with driving the solenoid at 5V is if the resistance of the solenoid prevents the I_PEAK value from being reached.

    Based on the functional block diagram on page 7 of the datasheet, a short from KEEP to GND will keep the device in the peak current mode. I have verified this behavior on a DRV120 part. The duty cycle in the peak current mode will settle at whatever value causes the current to be regulated at the I_PEAK level, as determined by R_PEAK. The only time the duty cycle will be 100% is if the device is first turned on, or if the resistance of the solenoid prevents the I_PEAK value from being reached.

    Because of the current feedback, the duty cycle varies to regulate the current through the solenoid. The steady-state duty cycle depends on R_PEAK if the device is in peak mode, or R_HOLD if the device if the device is in hold mode. Figure 1 on page 6 of the datasheet demonstrates this.

    Thank you for your question and let me know if I can help further.

    -Grant