UCC2803: How to reduce transformer turns with flyback use

Len Hsu2

Intellectual 2440 points

Part Number: UCC2803
Other Parts Discussed in Thread: UC2845AQ, UCC28740

Hi team,

I have a customer design in UC2845AQ and have some application questions.

The customer wants to increase the switching frequency for reduce the transformer turns.

(frequency to 172kHz；RT=10kOhm CT=1nF)

And will use flyback technology

over 3 years ago

0 Len Hsu2 over 3 years ago

TI__Intellectual 2440 points

Is there any way to calculate the transformer turns? Or there is any data that can provide for reference?

+1 Teng Feng over 3 years ago in reply to Len Hsu2

TI__Genius 13660 points

Hi Len,

The UCCx8C4x is an enhanced BiCMOS version with pin-for-pin compatibility to the industry standard UCx84xA family. There is a offline flyback design example in Section 9.2 in datasheet.

https://www.ti.com/lit/ds/symlink/ucc38c42.pdf

Below link is the UCC28740 flyback calculator.

https://www.ti.com/lit/zip/sluc487

I think you are finding a transformer calculator. attached a flyback transformer slide for your reference.

Regards

Surinder_Singh_-_transformer-designer-isolated-high-voltage-power-design.pdf

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UCC2803: How to reduce transformer turns with flyback use