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PMP10816: Transformer Winding

Part Number: PMP10816
Other Parts Discussed in Thread: UCC28710

Hi experts,

We are trying to design PMP10816 but we force to buy RLTI-1131 Transformer. We already send several mails to Renco Electronics for transformer winding details but they did not give any response.

As there is no information on TI website about transformer windings and other details even on WEBENCH we can’t design more than 25V 2A with UCC28710

So now we are start designing himself and make primary side 90uH with 50 Turns (28AWG X 3)

Secondary 24 Turns (22AWG X 3) and Auxiliary 11 Turns (28AWG X 1).

What we found...

  1. Supply did not start at 85VAC to 150VAC and its only work with load on 220VAC and after running some time it stops working. At the place of 48V We get around 44VDC
  2. Now we think this happened due to unstable VS pin we also try to adjust voltage divider and able to get 48V But after just some switching IC get damage no voltage on VDD pin
  3. We try with another transformer with 18 Turns auxiliary and rest of the winding are same then it start working on 85VAC but after some loading it stop working
  4. We check VS pin voltage which is varying which load up to 5.8V or move than this.


Please can you help me to find out what exactly turns number and turns ratio should I use to get PMP10816 out put