Everyone has been telling me that you must have an AC input to run a CW type charge pump but here it clearly states that is not so for a half wave version:

Voltage can be unipolar or bipolar, but current must flow in both directions.

Strange then that a Sim of a charge pump string works with a unipolar series of 5V

The circuit has a capacitor at the input. This means it will operate the same way on both bipolar and unipolar voltage. You can provide pulses with levels of -100V and +100V, or 0 and 200V, or even 200V and 400V; the output voltage will be the same. It is essential that the circuit you use to power the multiplier must allow current to flow in two directions; the output must be push-pull.
A little knowledge about how a capacitor works is enough to know that unidirectional current pulses won't flow thru it.

 

Very often , many simulators do not totally duplicate actual hardware. With a simple simulator that square wave DC supply has a zero output impedance at both zero and full voltage, so current can flow either way.
Now try it with a constant source voltage and a series switch that alternates between open and closed. It will not work.

 

Very often , many simulators do not totally duplicate actual hardware. With a simple simulator that square wave DC supply has a zero output impedance at both zero and full voltage, so current can flow either way.
Now try it with a constant source voltage and a series switch that alternates between open and closed. It will not work.

If what you say is true, then why does this simple 2-stage 555 unipolar-based voltage doubler work in both 'real world' and simulations? In fact the actual measurements are better than the simulation with 12V to 24V.

 

The 555 timer output stage is a totem-pole configuration, capable of both sourcing and sinking current.
This is what is needed to drive a charge pump.

If you think about it, it's producing an AC signal that centers around 1/2 Vcc, because it goes from 0V to Vcc.
The charge pump doesn't care WHERE the the AC is centered, the capacitor cannot pass the DC, only the AC portion of the signal gets through.

It's AC coupled, as long as the drive signal can push current in, and suck it out, - it works.

The first versions of the circuit you posted were fails because a single FET to GND can only SINK current, there was nothing to SOURCE current, so no output was generated.
The caps just reach a constant DC level and nothing happens.

The SIMULATOR versions work because the output looks like a perfect 0 impedance voltage source, which can source and sink.

Square wave AC or sine wave AC- it matters very little, its the ability to move current in BOTH directions that counts.

 

The 555 timer output stage is a totem-pole configuration, capable of both sourcing and sinking current.
This is what is needed to drive a charge pump.

If you think about it, it's producing an AC signal that centers around 1/2 Vcc, because it goes from 0V to Vcc.
The charge pump doesn't care WHERE the the AC is centered, the capacitor cannot pass the DC, only the AC portion of the signal gets through.

It's AC coupled, as long as the drive signal can push current in, and suck it out, - it works.

The first versions of the circuit you posted were fails because a single FET to GND can only SINK current, there was nothing to SOURCE current, so no output was generated.
The caps just reach a constant DC level and nothing happens.

The SIMULATOR versions work because the output looks like a perfect 0 impedance voltage source, which can source and sink.

Square wave AC or sine wave AC- it matters very little, its the ability to move current in BOTH directions that counts.

That’s helpful, thanks.

 

If what you say is true, then why does this simple 2-stage 555 unipolar-based voltage doubler work in both 'real world' and simulations? In fact the actual measurements are better than the simulation with 12V to 24V.
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My answer is that" That is not a simple circuit."