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TPS2660: PCB GND pad (device pin 17) was blowing up

Part Number: TPS2660

The eFuse P/N TPS26601 output supply 32v to Li-Ion 7-cell in series battery controller.

While try to connect battery cable to eFuse output the PCB pad of eFuse pin 17 was blowing up.

Circuit condition: 32v supply to eFuse and eFuse in operation before connecting, Battery almost in full charge condition 

The eFuse output used in battery controller for battery charging and battery heater PWM circuit as well as control circuit.

Attach eFuse circuit and PCB picture after damage (see U44 pin 17)

Would you have idea why the GND pad is blow up?

Thanks

Naftali

  • Hi Naftali,

    Thanks for reaching out!

    How are you making the connection from eFuse output to Battery? Does it introduces any inductance in the path ?

    Even a small difference (300~400mV) in voltage between eFuse input and battery can trigger fast-trip of the eFuse due to sudden increase in the current. If there is any inductance in the output path, the Vout node can swing -ve and can forward bias internal ESD diodes through GND pin.

    Can you capture Vin, Vout, FLT/ and IMON signals to understand better.

    Regards,

    Rakesh

  • Hi Rakesh,

    Thank you on rapid answer.

    The Battery was connected to eFuse using about 1m cable containing 3 wires for incoming battery positive power, 3 wires for battery GND (connected via connector and PCB GND plane to eFuse) and one wire connected between battery charging controller and eFuse output.

    I will try to do your measurements required in next week

    Thanks

    Naftali