One help (claimeth I) is to think of is as a boost converter, followed by a buck converter, and to re-draw it like this (left) so at least the polarities are the right way up. With its Ls and Cs, the Cuk looks very much like it should be some sort of resonant converter (even harder to visualise), but it is hard-switched just like a buck or a boost. Having never got past step A – how they work at all – let alone getting onto coupled-inductor variants, I had a really good read around and discovered a lot of explanations.Īn excellent one can be found on a website called SimonBramble, and it is well worth reading the Cuk section because of its refreshing approach. However, the output voltage has to be the opposite polarity to the input, which is not so neat for two reasons:ġ, for easy feedback it is nice to have everything on the same side of the 0V rail.Ģ, I struggle to think upside-down and the right way up in the same circuit, especially when inductors (with all their already difficult polarity-reversing-while-current-stays-in-the-same-direction behaviour) are involved. And can make output voltages higher and lower than the input with only one switch.
