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TPS4H160-Q1: Fault Condition

Ryan Sequeira
Prodigy 30 points
Part Number: TPS4H160-Q1

Hi All,

Am looking for a quick help on a condition. Any inputs appreciated.

We are using the TPS4H160-Q1. The V_BAT = 24Vdc. 

Am applying an abnormal fault condition where Vout can get faulted with a 48Vdc line accidently falling on the Vout_x. 

Current I am not enabling the Vout. Just by applying a 48Vdc on Vout, we observe the TPS4H160-Q1 is slightly heating up and the 48Vout source voltage drope to about 24.5Vdc ( which we presume is about 24Vdc battery + parasitic diode drop across the HSS_FET on that particular channel). The current drawn is about 42mA (max). 

This implies the TPS4H160-Q1 is powered by VBAT=24Vdc and/or diode ORedwith 48Vdc. Unable to reason why the 48Vdc drops to 24.5Vdc and what limits the current to only 42mA (as the TPS4H160-Q1 draws only about 7mA for its operation).

has anyone experienced this fault scenarion

  • 0
    TI__Mastermind 32650 points

    Hi Ryan,

    Please do not short the output to 48V. This is a 40V device and the abs max is at 48V. Any small voltage spike can cause damage above 48V.

    There is also no reverse current protection. Therefore connecting a higher voltage on the output will result in forward conduction through the body diode into the input source. 

    If the input source is a stronger source than the output short condition, it can pull the output voltage down especially if the 48V source is power limited.

    Still, this condition is not advisable and is not recommended by TI. 

    Thanks,

    Shreyas