Battery monitoring circuit and battery monitoring system
First Claim
1. A battery monitoring circuit that monitors voltages of a plurality of secondary cells connected in series, the battery monitoring circuit comprising:
- a first switch element with a first end connected to a first terminal, the first terminal connected to a first potential line and connected to a negative electrode of a first secondary cell;
a second switch element with a first end connected to a second terminal and a second end connected to a second end of the first switch element, the second terminal connected to a positive electrode of the first secondary cell and a negative electrode of a second secondary cell;
a third switch element with a first end connected to a third terminal and a second end connected to the second end of the first switch element, the third terminal connected to a second potential line and connected to a positive electrode of the second secondary cell;
a first capacitor with a first end connected to the second end of the first switch element;
an operational amplifier with an inverting input terminal connected to a second end of the first capacitor, a non-inverting input terminal connected to a fixed potential, and an output connected to the second end of the first capacitor;
an A/D converter configured to perform analog-to-digital conversion of a signal output by the operational amplifier to obtain a digital signal, and to output the digital signal; and
a control circuit configured to control an on state and an off state of the first, the second, and the third switch elements and to control operation of the operational amplifier and the A/D converter.
1 Assignment
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Accused Products
Abstract
A battery monitoring circuit monitors voltages of a plurality of secondary cells connected in series. The battery monitoring circuit comprises a first switch element, a second switch element, a third switch element, and a first capacitor. The battery monitoring circuit comprises an operational amplifier of which an inverting input terminal is connected to a second end of the first capacitor, a non-inverting input terminal is connected to a fixed potential, and an output is connected to the second end of the first capacitor. The battery monitoring circuit comprises an A/D converter which performs analog-to-digital conversion on a signal output by the operational amplifier and outputs an obtained digital signal. The battery monitoring circuit comprises a control circuit which performs on/off control on the first to third switch elements and controls operations of the operational amplifier and the A/D converter.
15 Citations
20 Claims
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1. A battery monitoring circuit that monitors voltages of a plurality of secondary cells connected in series, the battery monitoring circuit comprising:
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a first switch element with a first end connected to a first terminal, the first terminal connected to a first potential line and connected to a negative electrode of a first secondary cell; a second switch element with a first end connected to a second terminal and a second end connected to a second end of the first switch element, the second terminal connected to a positive electrode of the first secondary cell and a negative electrode of a second secondary cell; a third switch element with a first end connected to a third terminal and a second end connected to the second end of the first switch element, the third terminal connected to a second potential line and connected to a positive electrode of the second secondary cell; a first capacitor with a first end connected to the second end of the first switch element; an operational amplifier with an inverting input terminal connected to a second end of the first capacitor, a non-inverting input terminal connected to a fixed potential, and an output connected to the second end of the first capacitor; an A/D converter configured to perform analog-to-digital conversion of a signal output by the operational amplifier to obtain a digital signal, and to output the digital signal; and a control circuit configured to control an on state and an off state of the first, the second, and the third switch elements and to control operation of the operational amplifier and the A/D converter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A battery monitoring circuit that monitors voltages of a plurality of secondary cells connected in series, the battery monitoring circuit comprising:
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a first switch element with a first end connected to a first terminal, the first terminal connected to a first potential line and connected to a negative electrode of a first secondary cell; a second switch element with a first end connected to a second terminal and a second end connected to a second end of the first switch element, the second terminal connected to a positive electrode of the first secondary cell and a negative electrode of a second secondary cell; a third switch element with a first end connected to a third terminal and a second end connected to the second end of the first switch element, the third terminal connected to a second potential line and connected to a positive electrode of the second secondary cell; a first capacitor with a first end connected to the second end of the first switch element; an operational amplifier with an inverting input terminal connected to a second end of the first capacitor and a non-inverting input terminal connected to a fixed potential; a second capacitor connected between the inverting input terminal of the operational amplifier and an output of the operational amplifier; a refresh switch element connected in parallel to the second capacitor, between the inverting input terminal of the operational amplifier and the output of the operational amplifier; an A/D converter configured to perform analog-to-digital conversion of a signal output by the operational amplifier to obtain a digital signal, and to output the digital signal; and a control circuit configured to control an on state and an off state of the first, the second, and the third switch elements and the refresh switch element and to control operation of the A/D converter. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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18. A battery monitoring system that monitors voltages of a plurality of secondary cells connected in series, the battery monitoring system comprising:
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a first secondary cell; a second secondary cell, the first secondary cell and the second secondary cell connected in series; and a battery monitoring circuit configured to monitor voltages of the first secondary cell and the second secondary cell, wherein the battery monitoring circuit comprises; a first switch element with a first end connected to a first terminal, the first terminal connected to a first potential line and connected to a negative electrode of the first secondary cell; a second switch element with a first end connected to a second terminal and a second end connected to a second end of the first switch element, the second terminal connected to a positive electrode of the first secondary cell and a negative electrode of the second secondary cell; a third switch element with a first end connected to a third terminal and a second end connected to the second end of the first switch element, the third terminal connected to a second potential line and connected to a positive electrode of the second secondary cell; a first capacitor with a first end connected to the second end of the first switch element; an operational amplifier with an inverting input terminal connected to a second end of the first capacitor and a non-inverting input terminal connected to a fixed potential; a second capacitor connected between the inverting input terminal of the operational amplifier and an output of the operational amplifier; a refresh switch element connected in parallel to the second capacitor, between the inverting input terminal of the operational amplifier and the output of the operational amplifier; an A/D converter configured to perform analog-to-digital conversion of a signal output by the operational amplifier to obtain a digital signal and to output the digital signal; and a control circuit configured to control an on state and an off state of the first, the second, and the third switch elements and the refresh switch element and to control operation of the A/D converter. - View Dependent Claims (19, 20)
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Specification