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TPS4H160-Q1: How to choose TVS when driving the inductive load?

Rogers Chen
Intellectual 825 points
Part Number: TPS4H160-Q1

Dear TI experts,

We use TPS4H160-Q1 to drive multiple solenoid valves (inductive loads), each solenoid valve has a power of 5.5W, now we use bidirectional TVS to connect the OUTx port to deal with surge energy, instead of zener diodes, is this OK? How should the maximum power of the TVS be determined? Please help give some suggestions, many thanks!

  • 0
    TI__Mastermind 34985 points

    Rogers,

    Yes, adding a zener diode there is a perfectly acceptable solution for clamping the voltage on the output with inductive turn-off. Slide 9 of the following presentation does a good job explaining this:

    8750.2019_FAE summit_Driving inductive loads using power switches _cameron.pptx

    The device itself does have an integrated VDS clamp that clamps at 50V to 70V. When selecting the Zener clamp, you must ensure that that clamping voltage of the Zener is less than the minimum clamping voltage of the integrated VDS clamp (50V). 

  • 0 in reply to Timothy Logan
    Intellectual 825 points

    Hi Timothy,

    Thanks for your reply! Actually my question is, is it possible to use a bidirectional TVS instead of a Zener diode + unidirectional TVS to connect to the output to demagnetize the inductive load? I think bidirectional TVS looks like a better solution in terms of response speed and power, and at the same time, it saves board space and can be used to deal with ESD problems, what do you think? Also, I have read the PPT you submitted, I have another question, when the TPS4H160-Q1 switch is turned off, use the "clamp on FET" in the PPT, Vbat may reach -58V (Vbat=12V, while the highest VDS (clamp) of 4H160 is 70V), is this safe for the OUTx pin of 4H160? Many thanks!

  • +1 in reply to Rogers Chen
    TI__Mastermind 34985 points

    Rogers,

    Yes- it is fine to use a bidrectional TVS as long as it can withstand the energy requirements of discharging the inductance on the load.

    The OUTx pins can handle this voltage for inductive turnoffs as these are considered transient events. Steady state it obviously cannot stand a steady -58V, however the VDS clamp in the device is designed to withstand the max negative voltage of the clamp.