Bootstrap circuit in DC/DC static converters

Abstract

A bootstrap circuit in DC/DC static converters is provided that includes a power transistor having a first non drivable terminal coupled with a first input voltage and driving means connected with a drivable terminal of the power transistor and adapted for determining the on time and the off time of the power transistor for each prefixed switching time period. The bootstrap circuit includes a capacitor coupled respectively with the second non drivable terminal of the power transistor and with a second input voltage and an input of the driving means so that the voltage between its terminals is substantially equal to the voltage between the second non drivable terminal and the drivable terminal during the off time of the power transistor. The bootstrap circuit includes an overcharge circuit arranged between the second non drivable terminal and ground; the overcharge circuit is able to allow overcharging the capacitor during the off time of the power transistor and for a time period lower than the off time.

Dependencies are inferred from the claim text.