UCC28633: Protection to the UCC28633dr

Hi Rishav,

Thank you for the query. I assume you want to have a 500V protection for the HV pin.

This can be done by connecting a zener in series with the HV pin (as shown in Figure 44 of applications section of datasheet schematic as D10). Sufficient series resistors should be used to handle the maximum input voltage. The zener voltage should be chosen to limit the HV pin < 500 V.

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

Please let us know if you have any further questions

Thank you

Regards,

Harish