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UCC28600: 800VAC application discussion

Part Number: UCC28600
Other Parts Discussed in Thread: UCC28722, UCC28720

Hi team,

It is nice to know you here. My customer wants to use this device in below requirements,

  • VIN=800VAC, Vo=12V/0.1A, efficiency should be higher than 50%;
  • The No-Load power consumption should be as lower as possible;

Do you think UCC28600 can meet the above requirements?

BTW, what is the next-gen device of UCC28600? 

Thanks.

BR,

Charles Lin 

  • Hello,

    The UCC28600 was designed for high power fly back applications.  I am not sure it is the correct device for this application.

    You might consider using a PSR fly back using the UCC28722 that uses a BJT.

    The following link will bring to the data sheet for the ucc28722.

    The following application note describes how to design with the UCC28722 for a wide input range power supply for eMeter.  Even if you are not designing power for eMeter applications, I think you will find this application note helpful. 

    I also found a reference design using the UCC28720 PSR flyback controller that was designed for an input range of 184V to 707V AC that has a 12V, 1A output and a 3.3V 100mA output.  The following link will bring to this reference design and it may give you some more ideas on how you should design your fly back converter.

    Regards,

  • Hi Mike,

    Thank you for your recommendation here. For the UCC28720, the HV max input voltage is 700V, how to use 800VAC in this application? Thanks.

    BR,

    Charles Lin

  • Hello BR,

    The UCC28722 is the same device as the UCC28720 and does not have the internal high voltage startup.

    You would use trickle charge resistors to charge up the VDD capcitor.

    However, it you want to use the UCC28720 you could use a series pass regulator using high voltage NPN, TVS and resistor.

    1. NPN Collector to your high voltage input
    2. NPN Emitter to the HV pin of the UCC28720
    3. A resistor Collector to base to provide bias current to the TVS zener.
      1. Select a TVS with 650 V or less.
      2. The other option is a resistor divider.
      3. If use a TVS, tie the anode to ground and the Cathode to the base.

        Regards,