Portable device and semiconductor device
First Claim
1. A portable device connectable to a battery pack including a secondary battery, the portable device comprising:
- a charging circuit for charging the secondary battery when the battery pack is connected to the portable device, the charging circuit including a charging terminal used to supply the secondary battery with charging current and a voltage detection terminal used to detect voltage of the secondary battery in the battery pack, the charging circuit stopping charging of the secondary battery if a voltage abnormality is detected at the voltage detection terminal.
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Accused Products
Abstract
A portable device for preventing overcharging of a secondary battery resulting from contact failure of a voltage detection terminal. The portable device includes a charging circuit for charging the secondary battery when a battery pack, which includes the secondary battery, is connected to the portable device. The charging circuit includes a charging terminal, which is used to supply the secondary battery with charging current, and a voltage detection terminal, which is used to detect voltage of the secondary battery. The charging circuit stops charging the secondary battery when voltage abnormality is detected at the voltage detection terminal.
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Citations
17 Claims
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1. A portable device connectable to a battery pack including a secondary battery, the portable device comprising:
a charging circuit for charging the secondary battery when the battery pack is connected to the portable device, the charging circuit including a charging terminal used to supply the secondary battery with charging current and a voltage detection terminal used to detect voltage of the secondary battery in the battery pack, the charging circuit stopping charging of the secondary battery if a voltage abnormality is detected at the voltage detection terminal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A semiconductor device for use in a charging circuit of a portable device connectable to a battery pack including a secondary battery, wherein the charging circuit charges the secondary battery when connected to the portable device supplies the secondary battery with charging current, and includes a voltage detection terminal used to detect voltage of the secondary battery in the battery pack and a current detection resistor for detecting the charging current, the semiconductor device comprising:
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a current detection circuit connected to the current detection resistor to generate a current detection signal corresponding to the charging current flowing through the current detection resistor;
a first error amplifier connected to the current detection circuit, wherein the first error amplifier compares the current detection signal with a first reference voltage to obtain the difference therebetween and amplifies the difference to generate a first charge control signal with a voltage that causes charging to be performed at a constant current when the voltage at the voltage detection terminal is normal; and
a second error amplifier connected to the voltage detection terminal, wherein the second error amplifier compares voltage derived from the voltage of the secondary battery with a second reference voltage and amplifies the difference to generate a second charge control signal that causes charging to be performed at a constant voltage;
wherein the first error amplifier is supplied with the voltage of the voltage detection terminal and generates the first charge control signal with a voltage that causes charging to be stopped when the voltage at the voltage detection terminal is abnormal. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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16. A method for charging a secondary battery of a battery pack with a portable device that is connectable to the battery pack, wherein the battery pack includes a first voltage detection terminal used to detect voltage of the secondary battery in the battery pack, and the portable device includes a second voltage detection terminal connected to the first voltage detection terminal, the method comprising:
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connecting the battery pack to the portable device and supplying charging current to the battery pack from the portable device;
detecting the charging current and generating a current detection signal that is in accordance with the charging current;
comparing voltage of the current detection signal with voltage at the second voltage detection terminal; and
stopping the supply of charging current to the battery pack from the portable device in accordance with the result of the comparison. - View Dependent Claims (17)
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Specification