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UCC28630: need a protection circuit on the pin HV to use it with hight level voltage 684V

Part Number: UCC28630


I would use the UCC28630 component to make a flyback converter on a high AC voltage (484Vac rms, so 684Vpeak in input of my circuit). But in the datasheet, it is writen that is not possible to have more than 700V on this pin. Do you have a protection circuit to recomand me so I can use this component?


  • For this situation, you can connect a zener in series with the HV pin (this is shown in the datasheet application schematic Fig. 44 as D10 (optional is place of R2 in that case). Sufficient series resistors should be sued to handle the maximum input voltage. The zener voltage should be chosen to limit the HV pin < 700 V.

    Note that since the zener reduces the HV pin voltage, at low line it may limit the available HV pin input current, and hence limit the VDD cap charging current and lengthen the startup time.

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