Fully autonomous piezoelectric-based miniaturized robots usually have a high-voltage biasing system that provides the required voltage levels to drive properly their piezoelectric actuators. In this paper a novel on-board biasing system based on the cascade connection of three full-custom charge pump ICs is presented. Simulated and experimental results show that the proposed biasing system is capable to obtain a regulated output voltage up to 20 V from a 3.3 V battery and deliver successfully up to 120 mW of power. Moreover, a novel approach in the steady-state analysis of the two-phase voltage doubler (which is the core of the designed charge pump IC) has been developed in order to have a tool capable to provide a full understanding of the steady-state voltage doubler's behavior while at the same time accelerate and simplify the design process of such circuit. Simulated results show that the proposed mathematical model is more accurate than already developed models. The design of the charge pump IC has been implemented using a commercial 0.7 μm Bipolar-CMOS-DMOS (BCD) technology.