Patent attributes
A coulomb counter is provided. In the coulomb counter, a current generated on charge or discharge of a secondary battery is converted into a voltage by a resistor, and the voltage is amplified by an amplifier circuit. The voltage amplified by the amplifier circuit is converted into a current by a voltage-current converter circuit, and the current is input to a cumulative addition circuit. The cumulative addition circuit charges a capacitor with the current input from the voltage-current converter circuit and generates a signal corresponding to a voltage generated across the capacitor. One terminal of the capacitor is connected to an output of the voltage-current converter circuit through a switch, and the other terminal of the capacitor is supplied with a constant potential. By on/off of the switch, supply of electric charge to the capacitor and storage of the electric charge can be controlled.
