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PMP23340UCD: IOUT OC Fault

Part Number: PMP23340UCD
Other Parts Discussed in Thread: UCD3138A

Hardware:PMP23340UCD(UCD3138A)
Firmware:TI supplied routines——UCDIBCFirmware

The problems:The following error occurs after the reset is turned on to turn on the power supply.

Excessive output current and abnormal temperature display (-300°C?),Board rattles, then stops working.

There should be no problem with the program as the burn-in has worked fine many times before.

So can you give me some advice on how to fix or troubleshoot the problem?

  • Martin,

    You can disable OCP and OTP in the firmware.

    But the problem is that why the current is so large? Can you check if there is short circuit on the secondary side?

    The temp shouldn't go negative. what happen only if UCD is powered on but without input 48V?

    Regards,

    Sean

  • Hi,Sean

    I did what you said.

    However, disabling OCP and OTP in the software did not solve the problem.(Maybe I didn't disable OCP correctly.)

    If UCD is powered on but without input 48V,the temperature is still negative.

    I reset the input voltage and current ——(5V, 0.8A) and it works fine at this point.

    However, the input voltage and current were previously set to (5V, 0.5A) and were working fine before the problem arose.

    At one point it suddenly didn't work and there was a rattle on the board.

    Even though it's working properly now, I'm still not sure what caused the problem before.

    What problem triggered the OCP and what caused the temperature to be negative?It still confuses me.

    Regards,

    Yang

  • Probably the voltage from temperature sensing is changed. If you use memory debugger, you can read ADC result of temp sensing channel. Memory debugger can help you to find root cause.