Battery charger capable of suppressing the temperature increase of the power source circuit
First Claim
1. A battery charger adapted to supply current to a removable battery pack comprising battery cells and a charging terminal, comprising:
- a first terminal for coupling to an external power source,a second terminal for coupling to the charging terminal of the battery pack,a power source circuit coupled to the first terminal and the second terminal, the power source circuit transforming voltage input from the external power source, and supplying charging current to the battery cells, wherein the power source circuit includes a transformer which comprises a primary winding coupled to the first terminal, a first secondary winding coupled to the second terminal and a second secondary winding which is not coupled to the second terminal, wherein the voltage output from the second secondary winding has a linear relationship with the voltage of the primary winding,a voltage detector coupled to the second secondary winding, the voltage detector detecting the voltage output from the second secondary winding in order to determine the voltage input from the external power source to the power source circuit, anda processor coupled to the voltage detector and the power source circuit, the processor (i) determining the external power source voltage based upon the voltage output from the second secondary winding detected by the voltage detector, and (ii) determining a first allowable charging-current value, which permits charging while suppressing an increase in the temperature of power source circuit, based at least upon the determined external power source voltage.
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Abstract
Battery pack may include rechargeable battery cells Battery charger may include power source circuit. Power source circuit may be connected with an external power source and battery cells. The external power source may supply power to the power source circuit and then, the power source circuit may supply charging current to battery cells. Battery charger may also include voltage detector for detecting the voltage input from the external power source to power source circuit. Battery charger may further include processor for controlling power source circuit. Processor may determine the amount of charging current supplied to battery cells based upon the external power source voltage detected by the voltage detector.
49 Citations
12 Claims
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1. A battery charger adapted to supply current to a removable battery pack comprising battery cells and a charging terminal, comprising:
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a first terminal for coupling to an external power source, a second terminal for coupling to the charging terminal of the battery pack, a power source circuit coupled to the first terminal and the second terminal, the power source circuit transforming voltage input from the external power source, and supplying charging current to the battery cells, wherein the power source circuit includes a transformer which comprises a primary winding coupled to the first terminal, a first secondary winding coupled to the second terminal and a second secondary winding which is not coupled to the second terminal, wherein the voltage output from the second secondary winding has a linear relationship with the voltage of the primary winding, a voltage detector coupled to the second secondary winding, the voltage detector detecting the voltage output from the second secondary winding in order to determine the voltage input from the external power source to the power source circuit, and a processor coupled to the voltage detector and the power source circuit, the processor (i) determining the external power source voltage based upon the voltage output from the second secondary winding detected by the voltage detector, and (ii) determining a first allowable charging-current value, which permits charging while suppressing an increase in the temperature of power source circuit, based at least upon the determined external power source voltage. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An apparatus comprising:
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a battery pack comprising battery cells; and a battery charger comprising a power source circuit that transforms voltage input from an external power source and supply charging current to the battery cells, means for detecting the voltage input from the external power source to the power source circuit, and a processor that determines a first allowable charging-current value, which permits charging while suppressing an increase in the temperature of power source circuit, based at least upon the external power source voltage detected by the detecting means, wherein the power source circuit includes a transformer which comprises a primary winding coupled to the external power source, a first secondary winding coupled to the battery cells and a second secondary winding which is not coupled to the battery cells, wherein the voltage output from the second secondary winding has a linear relationship with the voltage of the primary winding, the detecting means detects the voltage output from the second secondary winding in order to determine the voltage input from the external power source to the power source circuit, and the processor determines the external power source voltage based upon the voltage output from the second secondary winding detected by the voltage detector. - View Dependent Claims (9, 10, 11, 12)
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Specification