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TPS54331: The temperature of tps54331 short circuit to ground is too high

hongwei duan
Intellectual 450 points
Part Number: TPS54331


When tps54331 is short circuited to the ground, the temperature of the chip will rise, which will cause the chip to fail due to the over temperature of the device caused by the junction temperature. What measures can be taken to reduce the current and temperature during chip short circuit.

  • 0
    TI__Mastermind 32440 points

    Hi Michiaki,

    Mathematically, Voltage/0=infinity. So short to GND will cause lots current to be drawn from any power supply. Short circuit condition is an external event to TPS54331. If the output is shorted, then current will increase as results. Then an over current runway can happen quickly.

    TPS54331 device increases the off time during short-circuit conditions by lowering the switching frequency by up to 8 times. Then if the condition continues, the device eventually will heat up; the thermal shutdown will be triggered to prevent the device from thermal runaway and damage . The device implements an internal thermal shutdown to protect the device if the junction temperature exceeds 165°C. The thermal shutdown forces the device to stop switching when the junction temperature exceeds the thermal trip threshold.

    So, thermal is consequence of excessive current draws due to short circuit condition. To reduce the current, a short need to be prevented in the first place, and if a short happens long time, the safest thing any power supply can do is to shut off. 

    Thanks !

    Tahar