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Original question:

DRV110: DRV110APWR

DRV110: State when the wiring to the solenoid is cut

Liu Yang
Expert 5915 points
Part Number: DRV110

Hi team,

When the wiring is cut, the OUT signal stops.
However there are some cases that when the wiring is reconnected,
the OUT signal does not recover (PWM does not work).
As for the state of the IC, I thought that during the HOLD state if the PWM was stopped and then reconnected
the HOLD state would continue.
What might be the reason why the OUT signal does not work in PWM in this way?
The EN signal is always on.

Beat Regards,
Tom Liu

  • 0
    TI__Expert 6330 points

    Hi Tom,

    I have notified our expert regarding this topic. Please expect a response by 6/2/20.

    Thanks,

    Aaron

  • 0
    TI__Expert 4940 points

    Hi Tom,

    DRV110 Out is controlled by the internal PWM block and Vsense feedback voltage. If Out doesn't toggle( high all time ) Vsense voltage doesn't reach the

    threshold set by Rhold. This will happened if external load limits Ihold, this current it is lower than target value. This current can be limited by an increase in load series resistance or lower load supply voltage.

    Another system explanation for this issue can be DRV110 Vin dropping below the under voltage threshold.

    My suggestion is to monitor DRV110 Vin, Vout, Vsense and load supply

    Regards,

    Costin

  • 0 in reply to Costin Cazana
    Prodigy 50 points

    Hi,

    Behavior when wiring to solenoid is cut
    When the wiring is disconnected, the OUT signal stops.
    When the wiring is reconnected, the OUT signal may not return (PWM does not work).
    The IC state remains in the HOLD state and pwm is stopped, and when it is reconnected,
    I thought that the HOLD state would continue.
    What could cause the OUT signal to not work?
    Also, the EN signal is always on.

    Best Regards,

    Kashiki

  • 0 in reply to user802161
    TI__Expert 4940 points

    Hi Kashiki,

    When load is disconnected that's no current thru Rsense, Vsense will be below the comparator threshold and Vout will be  continuously high.

    After reconnecting the load it should start normal hold PWM.

    The only think I can think about is a supply glitch causing under voltage  shut down. For a proper control of load on/off it is better to use a relay.

    Regards,

    Costin

  • 0 in reply to Costin Cazana
    Prodigy 50 points

    Hi Costin,

    Is there a way to avoid this problem occurring under voltage shutdown?
    For example, to turn off the power supply of the IC.

    Best Regards,

    Kashiki

  • 0 in reply to user802161
    TI__Expert 4940 points

    Hi Kashiki,

    Turning off IC supply will act like a reset, each time the power turns back on the sequence will be Ipeak followed by Ihold.

    In hold mode the load can be disconnected/connected with no affect on operation if load disconnect/connect doesn't generate glitches.

    Without scope picture when wire is cut and connected back it hard to estimate what has happened.

    When Vout stopped toggling what 's the Vout state: high ( Vin) or low(GND)? also can you monitor the Fault output?

    Regards,

    Costin