Rohm Co., Ltd.

Akihito Ito

Isao Yamamoto

Koichi Miyanaga

Yoshikazu Sasaki

Tetsuro Hashimoto

Yutaka Shibata

An external power source is connected to an adapter input terminal (first terminal). A battery is connected to a path input terminal (second terminal). A selection circuit (a first switch, a second switch, logic circuit compares the input voltage input from the external power supply with the battery voltage, and selects one of the two. The voltage thus selected by the selection circuit is output to an external load circuit via a system power supply terminal. A charging circuit charges the battery using the input voltage supplied from the external power supply.

Power management circuit

A start-up circuit receives a start-up signal instructing start-up of an equipment mounted with the circuit, and executes a predetermined sequence when start-up is instructed by the start-up signal. An oscillator generates a clock signal. A sequence circuit receives the start-up signal and a clock signal output from the oscillator, measures time by counting the clock signal when the start-up signal transits to a predetermined level, and executes a predetermined event at a predetermined timing. The oscillator operates for a period where the start-up signal is at the predetermined level if the start-up signal is at the predetermined level during the period the power key of the equipment mounted with the circuit is being pushed.

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Kyoto, Japan

Akihito Ito