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UCC25800-Q1: UCC25800-Q1

Parvin Sherakar
Prodigy 50 points
Part Number: UCC25800-Q1

Hi We are using UCC25800-Q1 . I was checking the reference design of this IC.

I am unable to understand the purpose of the R12 and R16 resistor divider here.

Could you please explain?

thanks

  • 0
    TI__Expert 7706 points

    Hi Parvin, R12 and R16 are resistors that help to charge balance capacitors C10 and C17 capacitors. When C10 and C17 are charged by the commutation of the internal switches of the UCC25800-Q1, they need a path to discharge, and they can do it through R12 and R16 respectively. How to choose their values is a trade of between conduction losses and start up time. If they are too large, the converter will take a lot of time to reach steady state, but conduction losses are negligible. If they are too small, conduction losses will be too high. For R12=R16=10kohm, they dissipate Ploss=2*(Vin/2)^2/R=45mW and take T=5*R*C=50ms as maximum to reach 15V in steady state.

    If you have any further questions let me know replying to this thread.