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TPS1H100-Q1: PWM controll for TPS1H100.

Dexter Choi
Expert 2795 points
Part Number: TPS1H100-Q1

Dear Sir,

My customer is using TPS1H100-Q1 and need PWM control by IN(pin3).

when PWM of duty 50% input at IN (pin3). it happened undershoot about -40V for OUTPUT at OUT (pin 5,6,7) as below picture.

could you advise me this problem. how to reduce undershoot.

PWM wave at IN (pin3)

OUT wave at OUT pin(5,6,7)

  • 0
    TI__Genius 12410 points

    Hello,

    This would happen if you have an inductive load on the output. This is not unexpected behavior as the clamp in the FET will turn it on at about -40V. I would say that I believe something is wrong with J20 because it should be clamping the negative pulse.

  • 0 in reply to Cameron Phillips
    Expert 2795 points

    Hello,

    I had removed J20 and tested it. but it is same operation.

    could you help advise me anything else?

    It is possible to use PWM control for this device?

    if non use, could you please recommend another current limit switch IC for AUTOMOTIVE as below specification.

    VIN: up to 40V

    function:

    PWM on/off control using Enable pin.

    programmable current limit up to 2A.

    need to Support AEC-Q100 

  • 0 in reply to Dexter Choi
    TI__Genius 12410 points

    Hello,

    This behavior is not bad. It is expected when you are driving an inductive load. D20 should clamp this to the VF voltage which for normal diodes will be 1-2V.

    With or without the D20 the device is working properly because it has to discharge the inductive energy.