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UCC28740: Selection criteria for flyback transformer

Part Number: UCC28740
Other Parts Discussed in Thread: TIDA-00709


I am designing a isolated flyback converter (85V-265V AC input and 12V, 3 A output) using UCC28740 IC and referring TIDA-00709 36W output sample design but unable to understand selection criteria for flyback transformer.

So, can you please tell me the information related to the UCC28740 as it can operate in CC and CV mode and operating switching frequency range of IC at the initial turn ON and steady state operation state?

Also please provide some sample calculation for selecting flyback transformer (85V-265V AC input and 12V, 3 A output) if possible.

Thanks & Regards


  • Hi Priyanshu,

    Please refer to figure 15 in the UCC28740 datasheet for the switching frequency range. Section 7.4.1 and 7.4.2 explains CV as well as CC operation using this device. You can refer to section of the datasheet for transformer calculations.

    Best Regards,
    Ben Lough