CURRENT INTEGRATED VALUE DETECTING DEVICE, CURRENT DETECTING DEVICE AND BATTERY PACK USING THEM

摘要

PROBLEM TO BE SOLVED: To provide a current integrated value detecting device, a current value detecting device and a battery pack using them which are insensitive for the offset of an operational amplifier or the like. SOLUTION: A detecting device is provided with a current detection resistor 2 inserted in series in a current passage of a battery 1, an integrator 5, an input condition selector 4 to introduce the electric potential at both ends of the current detection resistor 2 to the input of the integrator 5, an integration capacitor 6 connected to the integrator 5, and an integration capacitor inverting means 7 to switch the connection polarity of the integration capacitor 6 between the integrator 5 and the integration capacitor 6, the input condition selector 4 regularly and alternately switches two conditions of the condition (a) and the condition (b), and in the condition (a), the voltage corresponding to the battery current value generated at both ends of the current detection resistor is introduced to the input of the integrator 5, while in the condition (b), the battery current detection voltage generated at both ends of the current detection resistor 2 is inverted to introduce to the input of the integrator 5, or the voltage between terminals of the current detection resistor 2 is introduced to the input of the integrator 5 by assuming the battery current value in 0 condition. The integration capacitor inverting means 7 is alternately inverted synchronous to the condition (a) and the condition (b) of the input condition selector 4, and alternately switches the connection polarity of the integration capacitor 6.