Patent ID: 6798269
Filing Date: 2004-09-28
Classification: H02M,H03K,Y02B

Abstract:
A bootstrap circuit in a DC/DC static converter including 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 comprising:a capacitor coupled respectively with a 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; and an overcharge circuit for overcharging the capacitor during the off time of the power transistor for a time period lower than the off time, the overcharge circuit being coupled between the second non drivable terminal and a reference voltage.