Charging apparatus
First Claim
1. A charging apparatus for controlling a charging process in a manner such that a secondary battery is initially charged using a constant current as long as a terminal voltage of the secondary battery is less than a threshold voltage and,when the terminal voltage rises to said threshold voltage, the secondary battery is charged using a constant voltage less than said threshold voltage, the charging apparatus comprising:
- switching means for shutting off a charge current at a predetermined time;
comparing means for comparing a voltage difference between an output voltage of a power source when the charge current is shut off and a secondary battery voltage with a reference voltage; and
control means forswitching a charge voltage to a voltage higher than the output voltage of the power source when said charge current is supplied,switching the charge voltage to a voltage equal to the output voltage of the power source when said charge current is shut off, andswitching the charge voltage to a voltage equal to the output voltage of the power source when the charging is finished in accordance with an output of the comparing means.
1 Assignment
0 Petitions
Accused Products
Abstract
A charging apparatus controls the charging of a secondary battery such that charging is performed using a constant current as long as a terminal voltage of the secondary battery is less than a threshold voltage. When the terminal voltage rises to the threshold voltage, charging is performed using a constant voltage that is equal to or less than the threshold voltage. The charging apparatus includes a switch for shutting off the charge current at a predetermined time; a comparator for comparing (1) a voltage difference between an output voltage of a power source at the time of the shut-off of the charge current and a secondary battery voltage with (2) a reference voltage; and control means for (1) switching a charge voltage to a voltage higher than the output voltage of the power source when the charge current is supplied, (2) switching the charge voltage to a voltage equal to the output voltage of the power source when the charge current is shut off, and (3) switching the charge voltage to a voltage equal to the output voltage of the power source when the charging is finished in accordance with the output of the comparator.
35 Citations
4 Claims
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1. A charging apparatus for controlling a charging process in a manner such that a secondary battery is initially charged using a constant current as long as a terminal voltage of the secondary battery is less than a threshold voltage and,
when the terminal voltage rises to said threshold voltage, the secondary battery is charged using a constant voltage less than said threshold voltage, the charging apparatus comprising: -
switching means for shutting off a charge current at a predetermined time; comparing means for comparing a voltage difference between an output voltage of a power source when the charge current is shut off and a secondary battery voltage with a reference voltage; and control means for switching a charge voltage to a voltage higher than the output voltage of the power source when said charge current is supplied, switching the charge voltage to a voltage equal to the output voltage of the power source when said charge current is shut off, and switching the charge voltage to a voltage equal to the output voltage of the power source when the charging is finished in accordance with an output of the comparing means. - View Dependent Claims (2)
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3. A charging apparatus for controlling a charging process in a manner such that a secondary battery is initially charged using a constant current as long as a terminal voltage of the secondary battery is less than a threshold voltage and,
when the terminal voltage to said threshold voltage, the secondary battery is charged using a constant voltage less than said threshold voltage, wherein the charging is stopped at a predetermined time, when the charging is stopped, a voltage difference between an output voltage of a power source when the charging is stopped and a secondary battery voltage is compared with a reference voltage to yield a comparison result, upon charging, a charge voltage is switched to a voltage higher than the output voltage of the power source, and when the charging is stopped, the charge voltage is switched to a voltage equal to the output voltage of the power source in accordance with the comparison result, and after completion of charging, the charging is continued using a voltage equal to the output voltage of the power source.
Specification