In article ,
raypsi wrote:

I used to make a living selling capacitors for single stage charge pump they
were tagged with the name voltage doubler.

I'm building a 10 stage charge pump using 400wvdc capacitors rated at 22uf.
Running this pump from 220 VAC mains it's taking 3 capacitors for each stage.
Minus losses I should be getting around 3,300 vdc using a half bridge from
the split 220VAC mains here in the USA.

Although google is my friend I can't find much about charge pumps I've had
experience building ladder multipliers
I'm just hoping that the 1kPIV diodes will hold up to the task, they are
high speed 30amp surge.

Raypsi-

I'm not familiar with the term, "charge pump".

The 240 VAC mains in the US (NOT 220), have a maximum Voltage that can
be as high as 264 VAC since there is a ten percent tolerance. Peak
voltage could be as high as 373 Volts. The rectifier diode could charge
a capacitor up to 373 Volts DC. When the diode is reverse-biased during
the negative half of the cycle, the peak line voltage is -373. The
diode then sees the line voltage in series with the capacitor voltage
for a total of 746 Volts. At least for a simple rectifier, the 1000
Volt diodes might be sufficient.

As I understand voltage multiplier circuits, they consist of simple
rectifier circuits stacked. Output voltage is the sum of the charges on
a stack of capacitors. Rectifier voltages are also stacked so an
individual diode only sees the peak line voltage plus one capacitor's
voltage. If so, your 1000 Volt diodes should be OK.

If a diode actually sees peak line Voltage plus the sum of 2 capacitor's
Voltages, then 1000 Volt diodes would not be sufficient for any line
voltage above 236 VAC.

Fred
K4DII