STEP-DOWN DC-DC CONVERTER

摘要

PROBLEM TO BE SOLVED: To constitute a DC-DC converter having good characteristics using an N channel MOS transistor without providing a special voltage circuit having a voltage higher than the input voltage. SOLUTION: An N channel MOS transistor 11 and a choke coil 12 are connected in series between the minus side of a DC power supply and the minus side of an output capacitor 8. A PWM circuit 14 for applying a pulse signal to the gate of the MOS transistor 11 based on an input voltage divided by resistors 9 and 10 is provided. Power of the pulse signal being applied to the gate of the MOS transistor 11 is supplied between the plus side and minus side of the DC power supply. Pulse signal of the PWM circuit 14 is formed by a voltage corresponding to the output voltage from the output capacitor 8 and inputted to the gate of the MOS transistor 11 through a photocoupler 16. COPYRIGHT: (C)2006,JPO&NCIPI