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UCC28710: PMP20122 REV B Non-Isolated AC/DC Fail to Start/ No Output

Part Number: UCC28710
Other Parts Discussed in Thread: PMP20122


We are using circuit described in PMP20122 REV B. This is non-isolated universal input AC/DC Converter for output of 12V 500mA. After populating the components we are getting output voltage of just 0.45V. Also the Voltage on Vs pin is only 0.29V. We have used exact components values as per the BOM. Only we have changed the output inductor SLF12575T-470M2R7-PF (47uH) to the SRR1260-470M (47uH). 

Please suggest remedy / solution.


Vishwesh Limaye

Vihan Automations

  • Hello Vishwesh,

    May you please share your input condition. For better understanding please share the VDD, DRV, VS waveforms.

    If the output is only 0.45V then I suspect the controller is not even turning-ON because VDD is feed from the output rail. One way of moving forward is to disconnect VDD supply from the circuit and provide an external DC voltage of say 20V, this should turn-ON the controller and your design should start producing an output voltage.



  • Vishwesh

    Since there has been no reply to our follow up questions this thread will be closed. When you reply to the question it will reopen.

    Best Regards,