Comments on Why do DC/DC switching controllers seem to favour the buck-boost topology over similar ones like Cuk, SEPIC and Zeta?
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Why do DC/DC switching controllers seem to favour the buck-boost topology over similar ones like Cuk, SEPIC and Zeta?
I am looking at various DC/DC converter topologies for a power system I am designing. The most suitable topology for me is one that can perform both step-up and step-down functions, so I am looking into buck-boost and similar topologies like Cuk, SEPIC and Zeta.
While selecting the candidate ICs for the switching controller, I noticed a curios thing. On Digikey, where it is possible to filter by topology, the buck-boost & four-switch buck-boost topology occupies a large majority of the market. For instance, Digikey's catalog lists 471 active switching controller designs for a buck-boost topology, whereas for Cuk/SEPIC topologies there are only a handful of chips available (in the range of 15-20 chips).
Why is there such a preference for buck-boost topologies over Cuk and Sepic? Or is this just a shortcoming of Digikey's catalog?
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I'm not sure there's a technical reason, except usually the offered parts are multi-topology and then they could be listed as buck-boost while they at the same time could as well be used as flyback, SEPIC etc.
This seems to be the case for TI and Maxim, which at a glance seem to call everything "buck/boost". Whereas AD, who's probably still the market leader, seems to list them separately and offer roughly as many buck/boost parts as flyback or SEPIC.
In the case of catalog companies specifically, they might have many reasons why they only list certain parts. Most notably the ever changing, ever tiresome "linecards" of silicon vendors that they are allowed to sell from.
For example LT went completely bonkers some 10 years ago and decided that they would only sell their parts through Arrow. Didn't work out too well for them... Digikey & others would probably have liked to sell their parts, but they weren't allowed to.
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