TPS92513: TPS92513 blowing up on powerup at higher voltages

Part Number: TPS92513

I am having problems with the TPS92513 blowing up on power up at higher voltages. When applying power the TPS92513 fails and smokes. This happens when 36 volts is applied to the input of the circuit. This happens with both the HV and non HV parts. If voltage is slowly ramped up there are no problems. This problem happens on a hard power on. LED current is 300mA. To try fixing this I increased the inductance from 220uH to 470uH. The 470uH is an improvement, but it will still occasionally fails on a hard power on. Are there any suggestions on how to fix this so the TPS92513 does not fail on a hard power up?

  • Hello Jim,

    Usually hard power up damage occurs due to an overshoot on VIN due to parasitic inductance between the power supply and the board, whatever the output capacitance of the supply is, and the input capacitance to the circuit. 2.35uF input capacitance is pretty low, I would probably increase that to 10uF or more and that might be enough. But it would be best to use a scope to probe VIN under these conditions and see if that is the likely cause. Then increase the input capacitance to see if that helps. Ideally you test it with the final expected source because some supplies have huge output caps and if your leads are much longer than in the end app it may behave way differently.

    In short I would use more input capacitance and in the end you may need to add a TVS to the input to prevent exceeding abs max. Let me know if this is helpful or not, if it is something else we can investigate further.

    Regards,

    Clint

  • In reply to Clinton Jensen:

    I increased the input cap value to 100uF to see what happens, I don't have any lower capacitance values around to test right now. This increased capacitance value fixed the problem.