A VBOOST generator includes, for example, a voltage regulator for generating a first power rail VX between the supply voltage VCC and ground. A clock generator is arranged to generate a clock signal oscillating between the supply voltage VCC and the voltage VCC−VX. A charge pump is arranged to couple the voltage VCC−VX to a first terminal of an on-substrate flyback capacitor during a first half-cycle of the first clock signal and is arranged to couple the voltage VCC to the first terminal of the flyback capacitor during a second half-cycle of the first clock signal. A pin is coupled to the substrate couples the voltage VCC+VX developed on a second terminal of the flyback capacitor during the second half-cycle of the first clock signal to an external bucket capacitor. A second charge pump is optionally included to increase the charging capacity of the VBOOST generator.