Murata Manufacturing Co., Ltd.

Murata Manufacturingco., Ltd.

Masanari Tago

Kazunori Tsuda

Hidemori Akagi

Makoto Kawagishi

Tomoe Izumi

A DC-DC converter includes a capacitive power converter connected to a first terminal side, an LC circuit connected to a second terminal side and including an inductor and a second capacitor, and a control circuit that performs switching of a plurality of switch elements. The control circuit performs the switching at a switching frequency equal to or higher than a resonant frequency determined by the capacitance of the capacitive power converter and the capacitance and the inductance of the LC circuit, steps down an input DC voltage inputted to the first terminal, and outputs an output DC voltage from the second terminal.

DC-DC converter

A DC-DC converter includes n number of first series circuits each including an inductor and a switching element and a second series circuit in which n number of rectifier elements are connected in series with a same rectification direction. When n=2, one end of the second series circuit is connected to a node between an inductor and a switching element in the first series circuit and the other end of the second series circuit is connected to one end of a smoothing capacitor and one end of a load. A node between an inductor and a switching element is connected to a node between the rectifier elements via a capacitor. The odd-numbered switching element and the even-numbered switching element in the order of connection to the second series circuit are complementarily driven.

DC-DC converter with complementarily driven switching elements

A switching control IC is provided with a circuit for generating a triangular wave using a frequency that is dependent on a capacitor connected to a CT terminal of the switching control IC, and a resistor connected to an RT terminal thereof. A synchronizing signal input circuit for externally receiving a synchronizing signal that is a pulse voltage signal is connected to the CT terminal. A charging voltage for the capacitor connected to the CT terminal is changed by the synchronizing signal, which synchronizes the frequency of the triangular wave with the synchronizing signal, whereby the frequencies of a plurality of DC-DC converters are synchronized.

DC-DC converter and power supply device capable of synchronizing frequencies of a plurality of DC-DC converters

A frequency-selective high-frequency oscillator includes a first switching circuit that controls the operation of a first amplifying circuit, and a second switching circuit that controls the operation of the first switching circuit and a second amplifying circuit. Switching control signals are input to the second switching circuit. When the switching control signal is 'Low', the second switching circuit turns ON and the second amplifying circuit only operates, thereby outputting a high frequency signal with a resonant frequency according to a second resonant circuit. On the other hand, when the switching control signal is 'High', the second switching circuit turns OFF and the first switching circuit turns ON, which causes the first amplifying circuit only to operate. Thus, a high frequency signal with a resonant frequency acceding to a first resonant circuit is output.

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Nagaokakyo, Japan

Masanari Tago