Detecting a remaining battery capacity and a battery remaining capacity circuit
First Claim
1. A battery circuit capable of supplying an electric current to an external load outside the battery circuit and detecting a battery remaining capacity, comprisinga secondary battery, a storage capacitor, at least two switches, the first switch connecting the secondary battery to the storage capacitor and the second switch, and the second switch connecting the storage capacitor to the external load, and a storage capacity voltage monitor circuit coupled to terminals of the storage capacitor, wherein a remaining capacity of the secondary battery is measured by measuring a terminal voltage of the storage capacitor with the storage capacity voltage monitor circuit before the first switch is turned ON and a charge from the secondary battery flows to the storage capacitor, and measuring the terminal voltage of the storage capacitor with the storage capacity voltage monitor circuit after the first switch element is turned ON and then OFF.
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Accused Products
Abstract
A battery circuit, including a secondary battery, a storage capacitor, two switches and two voltage monitor circuits, detects a remaining capacity of the secondary battery and sends out data indicative of the remaining capacity to outside of the battery circuit. A first switch connects a secondary battery to a storage capacitor. A second switch connects the other end of the first switch to the storage capacitor and a load. A storage capacitor voltage monitor circuit measures voltage of the storage capacitor. The first switch is then turned ON and a current from the battery is transferred to the storage capacitor. At this time, the second switch is OFF. Then, the first switch is then turned OFF, and voltage of the storage capacitor indicative of the voltage of the secondary battery is measured. Then, the second switch turns ON and the current flows from the storage capacitor to the external load. The voltage across the capacitor is measured again and the remaining capacity of the battery can be accurately determined.
42 Citations
26 Claims
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1. A battery circuit capable of supplying an electric current to an external load outside the battery circuit and detecting a battery remaining capacity, comprising
a secondary battery, a storage capacitor, at least two switches, the first switch connecting the secondary battery to the storage capacitor and the second switch, and the second switch connecting the storage capacitor to the external load, and a storage capacity voltage monitor circuit coupled to terminals of the storage capacitor, wherein a remaining capacity of the secondary battery is measured by measuring a terminal voltage of the storage capacitor with the storage capacity voltage monitor circuit before the first switch is turned ON and a charge from the secondary battery flows to the storage capacitor, and measuring the terminal voltage of the storage capacitor with the storage capacity voltage monitor circuit after the first switch element is turned ON and then OFF.
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5. A battery circuit capable of detecting a remaining capacity, comprising
a capacitor and monitoring circuit adapted to couple terminals of the capacitor to a battery, the monitoring circuit including a first switch to selectively couple the capacitor to the battery and a second switch to selectively couple the capacitor to an external load, wherein the battery circuit is charged and discharged in accordance with a voltage measured across the capacitor.
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10. A battery circuit, comprising
a secondary battery, a capacitor selectively coupled to a load, a monitor circuit coupled to terminals of the secondary battery, at least one switch connecting the secondary battery and the capacitor, wherein when the monitor circuit measures a voltage of the secondary battery, the capacitor supplies current to the load, and the secondary battery is in an open state and does not supply current to the load.
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14. A method of measuring a remaining capacity of a secondary battery in a battery circuit and supplying a current to an external load outside the battery circuit comprising:
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selectively connecting the secondary battery to a capacitor via a first switch, the secondary battery charging the capacitor when connected to the capacitor when a potential difference exists between corresponding terminals of the secondary battery and the capacitor;
selectively connecting the capacitor to an external load via a second switch;
measuring a terminal voltage of the capacitor with a capacitor voltage monitor circuit coupled across terminals of the capacitor, measuring a terminal voltage of the capacitor with the capacitor voltage monitor circuit after the first switch is first turned ON and then OFF to connect and then disconnect the secondary battery and the capacitor; and
supplying a current to the external load outside the battery circuit. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21)
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- 22. A method of measuring a remaining capacity of a secondary battery by charging and discharging the secondary battery in accordance with a voltage measured across a capacitor selectively coupled to terminals of the secondary battery via a switch, the voltage measured after the current flows to the capacitor and the switch is turned OFF to uncouple the secondary battery from the capacitor.
Specification