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TPS56339: IC burns with LiPo battery

Part Number: TPS56339

Dear TI team

When I use a power source or low power batteries I can use the next circuit normally:

however for my application I am interested in using a 22.2VDC LiPo battery like: https://www.amazon.de/-/en/Helicopter-Aeroplane-Trex-550-Building-Aircraft/dp/B07QPSD9BG/ref=sr_1_7?dchild=1&keywords=lipo+25V+6S&qid=1612957170&sr=8-7

My IC burns when connected directly. Could you recommend appropriate circuit protection? My guess is that this is due to a too high inrush current due to the big battery capacity.

Thank you for your help

  • Hi Natalia,

    I didn't fully understand the connection method for the battery and TPS56339. How do you connect the power IC with the battery? Do you use a switch to directly connect battery and converter Vin bus?

    I think that might be like some hot plugging procedure and there might be a voltage spike on the input cap. If the voltage stress exceeds the abs maximum rating of IC, IC could damage then.

    From my thought, I think the easy solution is to add a Mosfet parallel with a starting resistor between converter input side and the port for batter. During the plugging in procedure, the Mos should be at off state and the resistor could limit the inrush current. When the Vin voltage for converter is stable, the Mos can be turned on to bypass the resistor.

    I think maybe first you can solder down the damaged IC and measure the waveform on Vin cap to check if there's a voltage spike.

    Thanks,

    Andrew

  • Hi Andrew,

    Thank you for your answer, yes I directly use a switch to power the IC to the VIN bus.

    Thank you for your suggestion, would you perhaps have an schematic of the solution for clarification? In some of my searches a thermistor was recommended, would you have a recommendation for it and for the mosfet parameters?

    Thank you in advance

    Best wishes

    Natalia

  • Hi Natalia,

    I think eFuse like TPS2660x/TPS1663x with integrated Mos can be used for easy design. For the recommended circuit, you can refer to the user guide of the EVM.

    Those products belongs to another product line and those devices are designed for the hot plugging case. I think you can consult them for more details.

    Thanks,

    Andrew