UCC3803: we need to calculate the transformer turns ratio, which we are unable to do.

Thank you for your prompt response.

(UCC3803)This design has come to us from the customer, and it is in working condition. We are also not sure of the topology. We assume it is flyback boost. 

But we need to calculate the transformer turns ratio, which we are unable to do.

And I am working on a simulation but cannot find the optocoupler in Tina software. How can I simulate the optocoupler in Tina software?

https://dr-download.ti.com/design-tools-simulation/calculation-tool/MD-KjdRGpwgFj/01.00.00.0B/slpc017b.zip The design of the transformer that we require is not included in this Excel sheet.

Yes, this is a flyback circuit, but the transformer polarities in this design are incorrect. Please suggest a similar reference design.

Hi,

The transformer turns ratios are calculated in the excel sheet. This excel file has a sheet of "Designs" in which you input your design specs. Then in the sheet of Flyback CCM or Flyback DCM, you can get the turns ratios and other transformer design parameter values..

Your circuit is ok but needs the transformer polarities corrected. As you are designing this converter, you need to know how the polarities should be. Or you may need to review some flyback design basics.

On the TINA opto coupler, let me have a look and I will reply to you when I see how it should be in TINA.