Switched Capacitor Negative DC To Positive DC Voltage Inverter

The circuit is a switched capacitor negative DC to positive DC voltage inverter. When the clock output is negative the switch Sw is in position 1, this connects the positive electrode of the flying/charge pump capacitor Ccp to ground and the negative electrode of Ccp to the negative terminal of power supply Vsn. This charges capacitor Ccp to Vsn. When the clock output is at ground the switch Sw is in position 2, this connects the negative electrode of capacitor Ccp to ground and the positive electrode of Ccp to the positive electrode of reservoir capacitor Cres. With the negative electrode of Ccp at ground, the voltage at its positive electrode is positive and therefore the positive electrode of capacitor Cres becomes charged to a positive voltage.