Voltage detecting device for assembled battery

A voltage detecting device for detecting a voltage of each of a plurality of unit batteries of an assembled battery, the unit batteries being connected in series, the voltage detecting device comprising:

• an operation amplifier having an inverted input terminal and a non-inverted input terminal;
• a plurality of first capacitors being correspondingly provided for the plurality of unit batteries;
• a plurality of first switches each being disposed between a high potential terminal of corresponding one of the unit batteries and a first end of corresponding one of the first capacitors;
• a plurality of second switches each being disposed between a low potential terminal of corresponding one of the unit batteries and the first end of corresponding one of the first capacitors, the low potential terminal having a potential lower than that of the high potential terminal;
• a plurality of third switches each being disposed between the inverted input terminal of the operation amplifier and a second end of corresponding one of the first capacitors;
• a second capacitor and a fourth switch being disposed in parallel between the inverted input terminal of the operation amplifier and an output terminal of the operation amplifier;
• and
• a control unit controlling the first switches, the second switches, the third switches, and the fourth switch to detect the voltage of each of the unit batteries, wherein
• the control unit:
• closes the first switches and the third switches to charge electric charge to the first capacitors, in a state where the fourth switch is closed and the operation amplifier is operated in a voltage follower;
• simultaneously opens at least one of the first switches or the third switches to hold the electric charge in the first capacitors;
• temporarily closes the fourth switch to reset electric charge of the second capacitor, while selecting one of the unit batteries in a predetermined order as a target unit battery for voltage detection;
• and
• closes one of the second switches corresponding to the target unit battery and one of the third switches corresponding to the target unit battery, in a state where one of the first switches corresponding to the target unit battery is opened, to detect the voltage of the target unit battery.

A voltage detecting device for detecting a voltage of each of a plurality of unit batteries of an assembled battery, the unit batteries being connected in series, the voltage detecting device comprising:

• an operation amplifier having an inverted input terminal and a non-inverted input terminal;
• a plurality of first capacitors being correspondingly provided for the plurality of unit batteries;
• a plurality of first switches each being disposed between a high potential terminal of corresponding one of the unit batteries and a first end of corresponding one of the first capacitors;
• a plurality of second switches each being disposed between a low potential terminal of corresponding one of the unit batteries and the first end of corresponding one of the first capacitors, the low potential terminal having a potential lower than that of the high potential terminal;
• a plurality of third switches each being disposed between the inverted input terminal of the operation amplifier and a second end of corresponding one of the first capacitors;
• a fourth switch being disposed between the inverted input terminal of the operation amplifier and an output terminal of the operation amplifier;
• a second capacitor and a ninth switch being disposed in series, between the inverted input terminal of the operation amplifier and the output terminal of the operation amplifier;
• a tenth switch being disposed between a common connecting point of the second capacitor and the ninth switch and a voltage line applied with a constant voltage;
• and
• a control unit controlling the first switches, the second switches, the third switches, the fourth switch, the ninth switch and the tenth switch to detect the voltage of each of the unit batteries, wherein
• the control unit:
• closes the first switches and the third switches to charge electric charge to the first capacitors, in a state where the fourth switch is closed and the operation amplifier is operated in a voltage follower;
• simultaneously opens at least one of the first switches or the third switches to hold the electric charge in the first capacitors;
• temporarily closes the fourth switch and the tenth switch to reset electric charge of the second capacitor, while selecting one of the unit batteries in a predetermined order as a target unit battery for voltage detection;
• and
• closes the ninth switch, one of the second switches corresponding to the target unit battery, and one of the third switches corresponding to the target unit battery, in a state where one of the first switches corresponding to the target unit battery is opened, to detect the voltage of the target unit battery.