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UCC28740: High Vout design check

user4773172
Intellectual 1410 points
Part Number: UCC28740
Other Parts Discussed in Thread: UCC28600, LM5023

Hi Sir,

May I learn from you that does UCC28740 can support below spec?

Vin 120~600V / Vout 400V 0.1A

If not, could you kindly suggest a TI solution could support this design spec?

Thank you for your kindly help.

Edward Chen

  • 0
    TI__Mastermind 40020 points
    Hello Edward,

    Based on this rather limited set of requirements, the tentative answer is YES.
    Can you please clarify if the input voltage Vin is AC or DC?

    If it is DC, then yes the UCC28740 can readily support that spec since the HV input is rated to 700Vdc and the input range is 600/120 = 5 to 1.
    Compared to the typical rectified-AC bulk voltage range of 375V peak to 70V in the valley, this range is 375/70 = 5.36 to 1.
    So the performance should be similar, just scaled to a higher voltage.

    If it is AC, then the UCC28740 can still be adapted to work, but the input range will be much wider since there will still be a lower-voltage valley extending to a higher voltage peak. The duty-cycle variation will be extreme and there will be much lower efficiency at the high line.
    Also, the HV input must be protected from voltages above 700V with a clamp such as are used in wide-range E-meter reference designs.
    Perhaps an alternative controller for wide-range AC input would be one of the UCC280x or UCC2813-x series of controllers or the UCC28600 or the LM5023.

    Given the high output voltage, I would recommend adding a secondary-side low-voltage auxiliary winding to bias the shunt regulator and opto-coupler circuits, to avoid excessive loss if biased directly from the 400V output.

    Regards,
    Ulrich