Learn about Valley Fill PFC

[budm]

See PDF.

[kaboom]

Re: Learn about Valley Fill PFC

R11, at .1 milliohm is not going to affect anything.
Where is the input current sense resistor on those drawings? It's mentioned in the text but nowhere to be found.

The value of the sense R would have do more to the PF than the alleged .1 milliohm "slowdown" resistor.

For R11 to even barely affect PF, it would be so large that efficiency would be absurd.

Think about it- it seems to be implemented as a simple RC time constant, "extending" the time it takes for the two caps to charge.

Personally, methinks this is another one of those "in theory only" announcements, rather than documentation of a built and tested circuit.

One tenth of a milliohm... Uh-huh.

[budm]

Re: Learn about Valley Fill PFC

Used in:

[tom66]

Re: Learn about Valley Fill PFC

Valley fill does work... The .1mohm is in error. The major issue with valley fill is voltage ripple is 1/2 the peak voltage which is difficult to design a PSU for.

[kaboom]

Re: Learn about Valley Fill PFC

Used in:

Yes, all of those except Philips (NXP) have much higher slowdown resistors!

100 ohms, 1K, 1.2K.

In the PDF in your OP, that resistor is ".0001" in the netlist. One tenth of a milliohm. Unless they meant ".0001M," which would be 100 ohms.

[tom66]

Re: Learn about Valley Fill PFC

My guess would be they had some convergence problems and they were simply playing around with it to make the simulation work better.

[budm]

Re: Learn about Valley Fill PFC

I can see them use this simple design for LED lightings with PFC.