Samsung Electronics Co., Ltd.

Hyung-wan Kim

Gil-yong Chang

Hyeong-sik Choi

A step-down converter is provided. The step-down converter includes a DC-DC converter including a boost capacitor and an NMOS transistor, the DC-DC converter converting an input direct current (DC) voltage to an output DC voltage; and an electric discharge circuit which adjusts the output voltage to be less than or equal to the input voltage.

Step-down converter maintaining stable operation at start up

A power supply protecting the electric device circuit when over-voltage is applied, is provided. The power supply has a rectifying unit rectifying AC power externally supplied, into first and second DC power and outputting the first and the second DC power; a main power supply transformer boosting the first DC power and supplying the boosted first DC power to the electric device circuit; a switching controlling unit driven by the second DC power, performing the operation on the main power supply transformer that causes the first DC power to be boosted when the second DC power is received; and a controlling unit determining whether the second DC power is to be supplied to the switching controlling unit, wherein the controlling unit senses the voltage supplied to the electric device circuit and interrupts supplying the second DC power to the switching controlling unit if the sensed voltage exceeds a given value.

Growing community of inventors

Suwon-si, South Korea

Hyung-wan Kim