Patent ID: 8325502

Claim:
A self-supply circuit, for a voltage converter having a main switch and a controller, designed to control switching of said main switch for controlling an output voltage, said self-supply circuit comprising: a charge accumulator, coupled to said controller and designed to supply a self-supply voltage to said controller; a generator, operable to supply a charge current to said charge accumulator; and a charge switching circuit, operable to control transfer of said charge current to said charge accumulator, and a precharge stage, coupled to said charge switching circuit and configured to carry out precharging of an intrinsic capacitance of said charge switching circuit, before a turning-off transient of said main switch ends; wherein said charge switching circuit comprises an auxiliary transistor having a gate terminal coupled to said precharge stage, and a second conduction terminal coupled to said generator, and said precharge stage comprises a precharge controller and precharge switching circuit; said precharge controller being configured to control said precharge switching circuit for supplying said self-supply voltage to said gate terminal during said precharging; and wherein said precharge switching circuit comprises a first switch, coupled between said second conduction terminal and a reference potential, and a second switch, coupled between said gate terminal and said charge-accumulator; said precharge controller being designed to close said first switch and second switch during said precharging.