Ricoh Company, Ltd.

Ritsuko Nomura

Masahiro Matsuo

Shohichi Nitta

Shoichi Nitta

A step-up/down DC-DC converter is disclosed that includes: a step-up/down part generating an output voltage by stepping up or down an input voltage; and a control part generating an error signal indicating an error between a voltage value obtained by dividing the output voltage and a predetermined reference voltage, and causing the step-up/down part to perform a step-up or step-down operation based on the comparison between the error signal and first and second triangle wave signals. The control part includes a first circuit generating the first triangle wave signal for step-down control and a second circuit generating the second triangle wave signal for step-up control. The first circuit generates a clock signal synchronized with the first triangle wave signal, and outputs the clock signal to the second circuit. The second circuit generates the second triangle wave signal synchronized with the first triangle wave signal based on the input clock signal.

Step-up/down DC-DC converter

A power supply apparatus includes a plurality of power source circuits, an oscillator circuit and a controller. The plurality of power source circuits use a common direct current power source. The oscillator circuit generates a plurality of oscillator signals. The controller performs a time sharing control based on the plurality of oscillator signals to enable the plurality of power source circuits to receive power from the common direct current power source in different timings and to output respective voltages.

Power supply method and apparatus

A power supply apparatus includes an output voltage generator, a reference voltage generator, a voltage divider, and a voltage control circuit. An input voltage is supplied from a direct current power source. The output voltage generator generates a constant output voltage based on the input voltage. The reference voltage generator generates a reference voltage. The voltage divider divides the constant output voltage into a divided voltage in accordance with a voltage dividing ratio variable in response to an externally-input control signal. The voltage control circuit controls the output voltage generator to regulate the constant output voltage such that the divided voltage from the voltage divider is equalized to the reference voltage.

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Osaka, Japan

Ritsuko Nomura