Boosting the input potential which is input into the power source supply

摘要

PROBLEM TO BE SOLVED: To obtain a power-supply circuit capable of outputting a constant voltage necessary for stably driving a load, irrespective of fluctuation in power supply voltage.;SOLUTION: A PMOS transistor M3, which connects the connecting terminal C1P connected to one end of a fly-back capacitor C1 to the output terminal OUT connected to one end of a catch-back capacitor Cout, is used to pump up the charges charged in the fly-back capacitor C1 to the catch-back capacitor Cout, thereby boosting the power supply voltage VCC. To make a constant voltage of an output voltage Vout, the output voltage Vout is fed-back to an error amplifier circuit 4 for controlling the gate voltage of the PMOS transistor M3 through a feedback circuit of the resistors R1, R2 connected to the output terminal OUT, thereby controlling the on-resistor of the PMOS transistor M3.;COPYRIGHT: (C)2009,JPO&INPIT