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UCC2813-0: Design

Part Number: UCC2813-0
Other Parts Discussed in Thread: UCC2813-5


I need your help as I am considering UCC2813 for an AC-DC converter.

I am considering a reference design

Please help me to get following queries clarified:

  1. What can be minimum VCC for UCC2813-0?
  2. I am not able to understand what does 0 suffix indicate in UCC2813D? I understand D stands for SOIC package
  3. It appears UCC2813 can't have VCC more than 11V (table 7.3 of device datasheet) but when I refer the schematic of the said reference design, I see 12V is fed back to VCC pin of UCC2813 using two diodes in series. Does this design ensure VCC is not subjected to above 11V?
  4. What is the purpose of R15 which is connected in series of C9?
  5. Can I modify the said reference design to produce output voltage to be 5V @ 1A?
  6. I see input range of the power supply is specified as 10.8VAC to 264VAC, 50Hz. What are the constrains to increase this input range? Can I modify the design to support the AC input range as 85VAC (RMS) to 300VAC(RMS)?

And finally, if you see any other design suggestion for above mentioned requirement, please do let me know.

Thank you for your attention and support on this request.



  • Hi

    (1) For the minimum VCC voltage, you need to make the VCC above UVLO_on. For UCC2813-0, the UVLO_on is 7.2 V.

    (2) Here are differences for different part number from UCC2813-0 to UCC2813-5. They have different turn on voltage of UVLO.

    (3) The maximum voltage of VCC is 12V. In recommended operating conditions, 11V is recommend by TI. The output is 12V. Two diodes are use for matching the VCC voltage.

    (4) When in high input voltage, the voltage accross C9 is equal to zero in start up process. The series resistor can help minimize the rush current to protect the cap.

    (5) You can modify the output. But you need to redesign you power stage parameters.

    (6) If you increase the input range, the duty cycle will be low. And you need to select a proper rectifier bridge and the filter cap C9. For high input range, the withstand voltage can meet the requirement.

    Jerry Xu