Battery charging and discharging control circuit which charges an expansion battery only if there is a full charge on an internal battery
First Claim
1. A battery charging and discharging control circuit for controlling charging and discharging of an internal battery of an electronic device and an expansion battery that is disposed separately from said internal battery, comprising:
- an internal charge switching circuit for supplying charging power to said internal battery;
an expansion charge switching circuit for supplying charging power to said expansion battery; and
a control circuit for controlling said internal charge switching circuit and said expansion charge switching circuit;
whereinsaid control circuit sets only said internal charge switching circuit to a conductive state so as to charge said internal battery when said internal battery is not in a fully charged state.
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Accused Products
Abstract
An electronic device including an internal battery and an expansion battery can not be operated when the charge in both batteries is drained. Accordingly, when charging the batteries, a control circuit, after confirming that the internal battery is not fully charged, sets an FET to a conductive state and an FET to a non-conductive state. The result is that charging occurs from the internal battery provided the internal battery is not fully charged. After the internal battery is fully charged, the control circuit sets the FET to a non-conductive state and the FET to a conductive state so that this time the expansion battery is charged. Thus, if a short operating time is sufficient, the internal battery can be rapidly charged so that the electronic equipment can be operated by itself after charging for only a short period.
18 Citations
23 Claims
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1. A battery charging and discharging control circuit for controlling charging and discharging of an internal battery of an electronic device and an expansion battery that is disposed separately from said internal battery, comprising:
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an internal charge switching circuit for supplying charging power to said internal battery; an expansion charge switching circuit for supplying charging power to said expansion battery; and a control circuit for controlling said internal charge switching circuit and said expansion charge switching circuit;
whereinsaid control circuit sets only said internal charge switching circuit to a conductive state so as to charge said internal battery when said internal battery is not in a fully charged state. - View Dependent Claims (2, 3, 4, 5, 6, 7, 9, 10, 11, 12, 13, 14, 15, 16)
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8. A battery charging and discharging control circuit wherein a battery charging control circuit for controlling the charging of an internal battery of an electronic device and a plurality of small expansion batteries that are disposed separately from said internal battery, comprises:
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an internal charge switching circuit for supplying charging power to said internal battery; a plurality of small expansion charge switching circuits disposed to respectively correspond to said plurality of small expansion batteries, for supplying charging power to corresponding said small expansion batteries among said plurality of small expansion batteries; and a control circuit for controlling said internal charge switching circuit and said plurality of small expansion charge switching circuits;
whereinsaid control circuit sets only said internal charge switching circuit to a conductive state so as to charge said internal battery when said internal battery is not in a fully charged state. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23)
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Specification