Rohm Co., Ltd.

Isaku Kimura

Shinya Kobayashi

Takahiro Shimizu

Yoshiki Kobayashi

A battery monitoring unit monitors at least one from among: (i) the attachment state of secondary battery pack; (ii) the low state of a battery voltage VBAT; and (iii) the state of whether it is possible or impossible to use the secondary battery. A battery measurement unit measures the battery voltage VBAT, a charge/discharge current IBAT, and a temperature T of the secondary battery pack, and converts the measured values into digital data. A charging circuit is configured to charge the secondary battery pack using DC voltage from an external power supply based on the state information detected by the battery monitoring unit and the information measured by the battery measurement unit. A coulomb counter measures the charge/discharge current IBAT at predetermined time intervals, and integrates the measurement value, thereby calculating the sum total of the charged/discharged amount. The battery management circuit is monolithically integrated on a single semiconductor substrate.

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Kyoto, Japan

Isaku Kimura