These circuits take a lot of parts to do a job that you can do with modern high frequency stuff with a lot lower cost and parts count.
The normal point of a capacitive doubler is either to give you a voltage you need without a lot of extra parts count (often negative) or to generate a very high voltage.
I did a tapped inductor boost last year to take 3V input to 80V output (at not-much output current, I forget exactly what it was but it was mostly a bias voltage; also, the actual output voltage was DAC-set and could be quite low, so the loop dynamics were unpleasant). It was definitely annoying to wrap my head around, and very annoying to select the inductor (Würth has a nice OTS series, at the usual Würth prices; HVM would likely want a custom or semicustom design) but it just plain worked the first try and continued working through the usual stress tests and also the unusual stress tests of the Very Expensive Load™ getting itself Very Expensively Killed™ (for non-power-supply reasons). I was really happy with that converter, that kind of step-up ratio isn't easy and it just worked.
A basic search coughs up a bunch of papers from academic paper mills, and I don't see obvious links to an OTS series from Wurth Elektronik.
I misremembered what design I actually ended up building. It was nominal 5V to 75V but was tested at a wider range (including the mentioned 3V to 80V). The variable voltage was implemented later, in a linear stage, which did in fact have a number of issues.
ADI app note AN-1126 was very helpful in this design. It pushes for a different topology, yet compares with this one and others in some detail. Its arguments against tapped inductor designs are threefold: (1) sometimes EMI issues on the switching node (fair, and a real concern, but not interesting for what I needed to do), (2) the inductor is annoying to source (very true), and (3) the main technical objection is that demands on the output rectifier are high and might require you to use something crappier than a Schottky. That last one is true in general but for this design in this decade, I was comfortably within medium voltage Schottky territory, and so their main objection was a complete nonissue. That looked good to me so I went ahead and built it, and was not disappointed.
The inductor was 744889030330 (say that three times fast) from the WE-MTCI family which worked a dream. I don't remember why this exact switcher chip was chosen but I do remember having a lot of candidates and so the choice was kind of arbitrary. The control scheme type it uses is important, though. I don't think the zener did anything but being paranoid I wanted to have the footprint there for the prototype build rather than not have it.
THE PREVIOUSLY PROMISED WARNINGS WHICH ARE ACTUALLY REALLY IMPORTANT SO I AM USING CAPS:
1. 80V can kill you. Really, it can. Use caution!
2. This is the design I sent off for fab (and perhaps not even the final version, if the folder notes are any guide). It is not the redlined, working version. I believe this stage was OK. Maybe it needed a bit more output capacitance? Certainly I know the following stage, not shown here, had severe issues (most of them stupid and obvious once noticed). So treat this as good inspiration, not ground truth.
3. Did I mention that 80V can kill you? USE CAUTION.
I will note that we're all talking about 10+ year old chips and technology--mostly prior to GaN.
Apparently, I'm going to have to dig through a bunch of stuff to see what is current. While the topologies don't change, the tradeoffs between them do as technology changes.
Edit: Stare at the LT7890/1/2/3 series for GaN stuff by way of comparison
It is also uncompromising and brutally difficult to get working well. GaN-FETs love to commit suicide in new and entertaining ways. And LTC7890 is not something I would want to implement in any design (though of course I'd suck it up and do it if it was the right choice).
99% of the market is traditional boring stuff because 99% of the market is well served by traditional boring stuff.
They have insane power density and lack of wound inductors means there's nothing that causes problems as you push into the kilovolts.
But really they're just more efficient (integer ratios, where `n-1` not prime) than classical Buck/boost topologies.
GaN stuff can be 99%+ efficiency. The frequencies are multiple MHz which shrinks the inductors significantly--sometimes allowing PCB based coils (See Anker 120W teardowns).
The datasheet mentions low profile a lot. That does make sense as one can make a flat, high quality, capacitor. Making a flat high quality inductor is harder and probably more expensive and likely consumes more volume overall. I can imagine some applications where being flat is important, like the back of a panel.
Integer ratios can be done with GaN and class 1 ceramics and stray inductance to charge the GaN drain, so they only experience ZVS (they don't need ZCS). Use a resonant gate drive. Efficiencies around 99.8% are feasible for a doubler/halver based on the "3L FC buck" topology, in the 10~30 MHz range.
EMC