Kabushiki Kaisha Toshiba

Katsuyuki Omi

Yuki Kamata

Eiji Hori

Daisuke Yamaguchi

Norio Nakamura

Masaru Hashimoto

Nobuyasu Goto

Toshio Shiramatsu

A DC-DC converter has an error amplifier that amplifies a potential difference between a first voltage based on an output voltage at the output terminal and a reference voltage, and outputs a resultant error amplified signal; a differential detecting circuit that senses an inclination of a temporal change of the output voltage by differentiating the first voltage, outputs a control signal according to a result of the sensing; and a PWM generating circuit that compares a synthetic signal obtained by conducting computation on the amplified error signal and the control signal with a periodically changing comparison signal, and outputs a PWM signal having a duty ratio controlled according to a result of the comparison.

Circuit

DC-DC converter

A delay-time variable filter delays an input signal by a desired time according to a control signal from a control input node and outputs the delayed input signal, and a positive feedback loop circuit changes the output signal (sinusoidal wave signal) from this filter, and provides a positive feedback of the binary pulse signal to the input side of the filter at a desired level for carrying out an oscillation. This positive feedback loop circuit includes a circuit for changing the signal into a binary signal and providing a positive feedback of the binary signal to the input of the filter by limiting the signal at a desired amplitude. As the delay-time variable filter, a quartic Butterworth low-pass filter is used, for example. As the positive feedback loop circuit, there is used a voltage comparator circuit that changes an input signal into a binary signal and outputs a pulse signal of a desired amplitude.

Voltage-controlled oscillator, phase synchronization circuit and signal processing circuit

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Kamakura, Japan

Katsuyuki Omi