Patent ID: 6744612
Filing Date: 2004-06-01
Classification: H02H

Abstract:
An inrush current protection circuit for a power supply including a rectification circuit coupled to a main body of said power supply through an energy-storage capacitor, said main body is provided with a reference voltage with a setup time greater than a threshold value, said inrush current protection circuit comprising:a current limiting resistor coupled in series between a negative terminal of said rectification circuit and a ground terminal of said energy-storage capacitor connected to a ground for preventing an inrush current from generation at an instant that the power supply is powered on; a switch coupled in parallel with said current limiting resistor and is-controlled under said reference voltage so as to switch from an open state to a short state after said reference voltage is set up, thereby to bypass said current limiting resistor; and a zener diode coupled in series between a reference voltage input terminal of said switch and a negative terminal of said rectification circuit for limiting a voltage across said switch.