Matsushita Electric Industrial Co., Ltd.

Matsushita Electric Co., Ltd.

Yoshio Mizutani

Takuya Ishii

Yoshinori Kobayashi

Satoshi Ikeda

Toshikazu Nagaki

Haruo Watanabe

Yutaka Sekine

A DC&mdash;DC conversion switching power supply is provided, including a plurality of DC&mdash;DC converters connected in parallel. A three-times frequency waveform which is generated from a three-times frequency waveform generation circuit, and is in sync with an oscillation frequency of the DC&mdash;DC converters is superimposed on a control voltage which is compared with a switching current signal in a current mode control circuit for controlling the DC&mdash;DC converters, or a signal proportional to the switching current signal to control a switching current pulse. Since superimposing the three-times frequency waveform which falls over one period increases the control voltage decreased by switch-on noise of the other DC&mdash;DC converter, malfunction at a switch-on phase of the other DC&mdash;DC converter, caused by the decrease of the control pulse width, is prevented.

Switching power supply

The interleaved switching converter circuit of the present invention includes: a first and a second switching converter which are connected in parallel to each other; a first control driver for turning ON/OFF the first switching converter; a charger/discharger having a first and a second capacitor and alternately charging/discharging the first and the second capacitors, in response to the turn ON/OFF of the first switching converter; and a second control driver for turning ON/OFF the second switching converter in synchronism with an inversion of a difference between voltages of the first and the second capacitors.

Variable frequency switching of synchronized interleaved switching

An AC-DC converter which allows an input current of an input AC power source to have harmonic currents of reduced levels and which supplies a stabilized output DC voltage to a load is realized by a simple circuit configuration. The converter has: a converter circuit consisting of a choke coil which receives a rectified voltage from a rectifying circuit, a switch element, and a diode; a smoothing capacitor which smooths the output voltage of the converter circuit and supplies the smoothed voltage to a load; and a control circuit consisting of a current detection circuit, a voltage detection circuit, and a pulse-width control circuit. In order to stabilize the output voltage, the switch element is turned on and off so that the peak value of the input current of the converter circuit is limited in a DC-like manner, thereby allowing the input current to have a trapezoidal waveform.

AC-DC converter

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Tsu, Japan

Yoshio Mizutani