| 摘要 |
PROBLEM TO BE SOLVED: To provide a supply voltage step-down circuit using an Nch transistor as an output stage which can reduce effects of noise generated in a step-up circuit. SOLUTION: The supply voltage step-down circuit includes an output N channel transistor with one end supplied with a first voltage of supply voltage and the other end functioning as an output terminal, a step-up circuit for stepping up the first voltage to generate a second voltage higher than the first voltage, a step-down circuit for stepping down the second voltage to generate a third voltage higher than the first voltage and lower than the second voltage, and an amplifier powered by the third voltage for amplifying a difference between a reference voltage and a voltage at the output terminal to generate a fourth voltage and supplying the fourth voltage to the gate of the output N channel transistor. COPYRIGHT: (C)2010,JPO&INPIT |
