Battery capacity computing apparatus
First Claim
1. A capacity computing apparatus for computing the capacity of a secondary battery, comprising:
- a current-detecting resistor means connected in series with said secondary battery for detecting charging and discharging current of said secondary battery;
amplifying means for amplifying the output signal of said current-detecting resistor means, said amplifying means having a first amplifier which amplifies the output signal of said current-detecting resistor means when said secondary battery is charged, and a second amplifier which amplifies the output signal of said current-detecting resistor means when said secondary battery is discharged;
computing means for computing the capacity of said secondary battery on the basis of the output from said amplifying means;
a D/A converter which converts a digital signal as a reference generated from said computing means to an analog signal; and
comparing means for comparing the analog signal generated from said D/A converter with the output from said amplifying means, and outputting the comparative result to said computing means,wherein said computing means computes the capacity of said secondary battery in response to the comparative result.
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Abstract
A capacity computing apparatus for computing the capacity of a chargeable secondary battery by a microcomputer, wherein a resistance is connected to the secondary battery and a drop voltage because of charging and discharging current in the resistance is amplified by an amplifier, whereby the capacity of the secondary battery is computed on the basis of the amplified value. The capacity of the secondary battery is computed with good accuracy even with a small drop of the voltage in the resistance. Moreover, an influence of an offset voltage in the amplifier is removed by applying a constant voltage to the amplifier at all times. The stored value of the microcomputer is periodically updated, thereby avoiding an influence when the amplification degree of the amplifier is changed due to the temperature change.
50 Citations
13 Claims
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1. A capacity computing apparatus for computing the capacity of a secondary battery, comprising:
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a current-detecting resistor means connected in series with said secondary battery for detecting charging and discharging current of said secondary battery; amplifying means for amplifying the output signal of said current-detecting resistor means, said amplifying means having a first amplifier which amplifies the output signal of said current-detecting resistor means when said secondary battery is charged, and a second amplifier which amplifies the output signal of said current-detecting resistor means when said secondary battery is discharged; computing means for computing the capacity of said secondary battery on the basis of the output from said amplifying means; a D/A converter which converts a digital signal as a reference generated from said computing means to an analog signal; and comparing means for comparing the analog signal generated from said D/A converter with the output from said amplifying means, and outputting the comparative result to said computing means, wherein said computing means computes the capacity of said secondary battery in response to the comparative result. - View Dependent Claims (2)
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3. A capacity computing apparatus for computing the capacity of a secondary battery, comprising:
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current-detecting means for detecting charging and discharging current of said secondary battery; reference signal generating means for generating a reference signal to be superposed to the output signal of said current-detecting means; amplifying means for superposing and amplifying the output signal of said current-detecting means and said reference signal; and computing means for computing the capacity of said secondary battery on the basis of the output from said amplifying means. - View Dependent Claims (4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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Specification