# Conceptual confusion about voltage multiplier circuits

I can do circuit analysis of the half-wave series multiplier (also called Villard or Greinacher cascade or Cockcroft-Walton multiplier) and see that it works, but I have several conceptual confusions about it stemming from how it is almost universally explained: each stage is a clamper that shifts the waveform up by the peak voltage, whose output is sent to a filtered half-wave rectifier (i.e. a peak detector) to produce a smooth doubled output DC voltage. It is explained that if we want to produce a V$_{out}$ = NV$_{in}$, that we string together N of these stages.

For clarity I've separated the following three confusions but I think they are just helping to explain the same central question.

1) My first confusion is that if we wish to ultimately produce smooth DC output, it would make the most sense to save N-1 diodes by only doing the smoothing after the voltage multiplication. And yet most online resources describe the smoothing as being somehow integral to the operation of each stage, without explaining why. This is particularly confusing because if the output waveform really were smoothed to a constant DC voltage at each stage, then the polarity would not change for the next stage and it would therefore be unable to do its job!

2) My second confusion is related to the first: why can't we therefore just get rid of the rectifier in each stage and just string together clampers (and save any smoothing to the end)? The reason this is particularly confusing is that both circuits are actually the same circuit, that is, a daisy chain of 2N clampers (swapping polarity for each added clamper), is the same circuit as a daisy chain of N (clamper + filtered rectifier).

3) My third confusion is that if I really were to understand the multiplier as a chain of clampers and filters in series, then I would expect V$_{out}$ to be between the two "rails" rather than between a ground placed next to V$_{in}$ before the first stage, and the output of the last stage (as in this diagram).

Again, I can successfully do circuit analysis on the multiplier circuit, but I've found all of the common conceptual descriptions to be very confusing.

• The diodes ensure that the shifted voltage does not drain back to its base potential. Oct 9, 2017 at 6:47
• Yes, typically it's explained that we want a clamper + filter, and the diode is to prevent the cap from draining. But this doesn't affect my above confusions. Oct 9, 2017 at 6:54
• Why do you have this distinction between "clampers" and rectifiers? The diodes are all the same, and are being used to switch the capacitors from a parallel configuration (charging the capacitors) to a series configuration (doubled voltage output.)
– JRE
Oct 9, 2017 at 7:53
• You are preaching to the choir, hence my question. Oct 9, 2017 at 15:01
• What's a clamper? Oct 9, 2017 at 15:33