Why do PFC controllers not permit independent output overvoltage setting?

[treez]

Hello,
Do you know why virtually all PFC controllers give you no choice over the output overvoltage threshold level?
I mean, take the PFS7623H PFC controller …
https://led-driver.power.com/design-support/product-documents/data-sheets/hiperpfs-4-data-sheet/

….This (its error amplifier) has a feedback reference of 3.85V…..and the feedback signal is also internally connected to a Overvoltage comparator with a reference voltage of 4-4.1V. Being internally connected mean you cannot adjust it.

This means that with a 200W PFC stage, one must have a PFC output capacitance of at least 150uF so that you don’t keep tripping the OVP with normal 100/120Hz output ripple voltage.
This is extremely inconvenient for people who want to use all Film capacitors at the PFC output.
I can only find one PFC controller on the market that allows one to independently set the output overvoltage level (the LT1248).

Needless to say, digikey etc unfortunately don’t allow one to sort PFC controllers on “independent OVP setting”.

 

[Easy peasy]

add a comparator - do your own ....

 

[treez]

Thanks, you've hit the nail on the head......these controllers connect the FB pin internally to an internal overvoltage comparator......so its not actually even possible to add a comparator and do your own Overvoltage level setting. [apart from that is, of course, on the LT1248, which is the only single PFC controller on the entire market which allows to do what you kindly describe (add a comparator)].
..I suppose its my fault for being such a Luddite and not using a microcontroller based PFC controller.