Patent ID: 7531989

Claim:
A battery fuel gauge circuit for measuring a capacity of a rechargeable battery pack, the battery pack being capable of generating a battery voltage and a discharge current, the battery pack having a temperature, the battery fuel gauge circuit comprising: an amplifier circuit capable of sensing the discharge current and the temperature of the battery pack and generating a first and a second voltage signals based upon the discharge current and the temperature; a correction circuit capable of receiving the first and the second voltage signals and generating a plurality of voltages; a plurality of comparators capable of receiving a reference voltage based upon the battery voltage, the plurality of comparator comparing the reference voltage with the plurality of voltages from the correction circuit and generating a plurality of digital signals; and a multiplexer capable of receiving the plurality of digital signals from the plurality of comparators, and controlling an external indicating circuit to indicate the capacity of the battery pack based upon the plurality of digital signals.