UCC28780: Turn off Over Power Protection

Ivan Andelic

Part Number: UCC28780

Hello,

I am using UCC2870 for my Activ Clamp Flyback Converter and my goal i to make a Converter with a output power 160W (Vo=40V and Io=4A). I am Using your UCC28780 GaN SIMPLIS Model (45W Output Power) for my Simplis Simulation. I already changed the Parameters for the (Rvo1 and Rvo2) and it worked i got something about Vo=40V and Io=4.3 A but after 160ms of Simulation, the Over Power Protecion turns on and breaks up!

I tried to program it by changing the Values of Ropp and Rcs but it Didnt work. Can you please tell me which Parameters i need to change, to become a activ clamp Flyback Converter with Po=160W. And how i can Calculate that?

Thanks!

Ivan

over 6 years ago

0 Benjamin Lough over 6 years ago

TI__Mastermind 27105 points

Hi Ivan,

Thanks for your interest in TI. Overpower protection uses the CS pin voltage. The voltage on the CS pin is likely too large and tripping OPP. A 160W design is very different from a 45W design. You will need to make adjustments to the power stage such as using a lower current sense resistor to avoid tripping OPP. I would suggest walking through the UCC28780 design calculator to understand all the adjustments that would be necessary. You can find the calculator at the bottom of this page:www.ti.com/.../toolssoftware

Best Regards,
Ben Lough

0 Ivan Andelic over 6 years ago in reply to Benjamin Lough

Prodigy 70 points

Hello Ben,
thank you for your fast response! I will try it with the design calculator.

Best Regards
Ivan Andelic

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UCC28780: Turn off Over Power Protection