Patent Number: 6,295,214

Title: Switching power supply unit

Abstract: A switching power supply unit, which rectifies and smoothes an AC current and an AC voltage from the on-off switching operation of a main switching element to output a DC current and a DC voltage, has an output current detection circuit including a current detection resistor disposed in an intermittent-current flowing path through which a current intermittently flows in sync with the on-off switching operation of the main switching element, a synchronous rectifying a switching element for rectifying a current flowing through the current detection resistor, and a capacitor for charging the current rectified by the synchronous rectifying element, wherein the current flowing through the current detection resistor is charged in the capacitor by a rectifying operation of the synchronous rectifying element, and the charging voltage of the capacitor is outputted as a voltage corresponding to the output current of the switching power supply unit.

Inventors: Matsumoto; Tadahiko (Yokahama, JP), Nishiyama; Takayoshi (Yokahama, JP), Nagai; Jun (Sagamihara, JP)

Assignee: Murata Manufacturing Co., Ltd.

International Classification: H02M 3/24 (20060101); H02M 3/335 (20060101); H02M 003/335 ()

Expiration Date: 09/25/2018