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PMP10491: pmp10491 DC-DC flyback converter having a synchronous rectification circuit

Augurio Gennaro
Prodigy 20 points
Part Number: PMP10491
Other Parts Discussed in Thread: PMP

I needs more informations about pmp 10491 evaluations board. For example i need to understood operations of syncronous rectifier and how i can reduce output voltage to 3,3 volt

  • 0
    TI__Intellectual 2530 points

    Power Supply Design Seminar topic slup204 is a good introduction to the synchronous flyback converter.  You can search the TI website for this document.  You will need to sign up for a TI account (if you don't have one) to view this document.

    Changing the output from 5V to 3.3V will require a new xfmr with a different turns ratio.  Other components such as the output sync FET, feedback network, and output capacitors will also need to be changed.

  • 0 in reply to David Strasser
    Prodigy 20 points 
    Thank you David, your advice has been very useful.
The calculation I performed gives me a primary inductance Lp = 7uH and a ratio turns Np: Ns = 2: 1, with fsw = 500kHz and the DCM-CCM transition of about 7 watts.
These values ​​are the same as those of the Sumida C91181 transformer used on PMP10491, although my transformer is designed for the main output of 3.3 Volt -1.5A (plus outputs for others 7Watt).
Can you confirm that PMP 10491 is also designed for mixed DCM CCM functionality?
Thank you very much.
Gennaro