integrated voltage multiplier circuit for low supply voltage . in order to improve the signal - to - noise ratio in battery - operated switched capacitor filter circuits in hearing aids , the range of modulation can be increased by doubling the supply voltage . a circuit for voltage multiplication in cmos technology generates a negative voltage for a given voltage . in order to be able to utilize both clock phases , a two - stage embodiment is selected , both of these working onto a smoothing capacitor . the voltage multiplier circuit is driven by a fourth inverter stage and with a level converter having a connected , third inverter stage .