Hi,

Suppose you are doing a Boost PFC for 205-250VAC input, 400V output and 250W power.

Then the way to find the inductor value is to get the switching frequency. Then you design a Boost converter for the Static case of Vin = 205*sqrt(2), and Vout = 400V and Pout = 2*250W. Using the equation Vout/Vin = 1/(1-D) , amongst others, one then assess’s what inductor value gives you the tolerated level of inductor ripple current. Thus you get your inductor value.

….However, one cannot do this with the HiperPFS-3 controller, because you have no way of knowing what the switching frequency will be.

There is a graph on page 7 of the HiperPFS-3 datasheet (Fig9a) which shows switching frequency at mains peak for various mains input voltages….but it does not give switching frequency for 205VAC. Also, Fig9a must only be relevant for a particular value of Vout, but fig9a does not say what this vout value is.

So how do you calculate the needed Boost PFC inductance value for HiperPFS-3?

HiperPFS-3 Boost PFC controller datasheet:

https://ac-dc.power.com/sites/default/files/product-docs/hiperpfs-3_family_datasheet.pdf