PWM Push-Pull Square Wave w/ Espruino to drive Voltage Multiplier

I try do drive with a Pico without extra hardware a passive voltage multiplier made w/ Cs and Ds to control a VCO that needs 1..10V to get the full range.

How would I do that?

PWM does not what I need... it only does the push... but not the pull down.... It gives me though access to frequency and duty cycle...

Voltage Multiplier - one of the many:

• https://www.electronics-tutorials.ws/blo­g/voltage-multiplier-circuit.html