Open Feedback loop protection for UCC28070A PFC controller?

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cupoftea

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Hi,
Would you agree, if an upper output divider resistor in UCC28070A based Boost PFC circuit is absent, then output will just get severely overvoltaged?

UCC28070A datasheet.


.there appears to be no overload timer, which would turn off a "normal" controller after say 500ms of the error amplifier saturating high.

(BTW, this is good news , because it appears to mean that we can simply unhook the gate driver(s) from the FET(s), and check the gate drive signals are correct, without the FETs being connected)
 

Hi,
We wish to remove the FETs, and inspect the gate drive output of UCC28070A.....how do we do this?....do we set VSENSE to 2.9V, VINAC to ~2.7V or lower, then we will see the gate drives working on the scope?
 

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