Hi team,
My customer design condition is Vin 9~27V Vo=3.3V Po=3W. But I use cal tool or webench that get transformer ratio is 4:1(Pri:Sec).
And efficiency only 65%. Can I adjust the transformer ratio to 1:1 that get efficiency up to 80%.
I want to know if there are other Impact when I change transformer ratio.
Hi Jimmy,
Thank you for posting. I ran the design calculator, and the efficiency can be increased by raising the Lmag. The calculator gives the min Lmag to be 3.8uH, and it the min, and your selection should be higher. I tried 15uH, and 2:1 turns ratio, the predicted efficiency can reach 80%.
Note that the calculator offers some flexibilities and you should be able to play with it to get a better efficiency. A rough idea is try to enable the BCM under the nominal input voltage, in this case the 18Vin. Also, always verify, and fine tune the circuit by experiment.
Hope this helps.
Regards,
Youhao
