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UCC256403: Burst off period setting

Part Number: UCC256403

Hi Sir,

 My customer is designing UCC256403 and want to decide its Cboot capacitor and we see a 150ms burst off period time in datasheet. They have question about burst off period setting time: how to decide the value? 150ms is ok for general application or how to calculate / measure it? Thanks for your kindly help.

Best regards,

Gary Teng

  • Hi Gary,

    By raising the burst mode threshold, you can increase burst off duration. The output voltage's ripple would rise as a result. Additionally, because the burst mode threshold is larger during the burst on period, primary mosfets can easily attain ZVS.

    The output voltage ripple will be reduced by lowering the burst mode threshold, however switching frequency will rise during the burst on period. As a result, switching losses will rise. Additionally, because of the greater switching frequency, ZVS may not be achieved.

    Therefore, everything depends on the particular application and must be assessed on the bench.


    Manikanta P