| 摘要 |
PROBLEM TO BE SOLVED: To provide a charging circuit capable of charging with a stable charge current while avoiding a secondary battery from being exposed to a high temperature.SOLUTION: The charging circuit includes: a secondary battery 1; power supply means 2 that supplies a charge current; a positive temperature characteristic sensitive resistance 3 the resistance value of which increases sharply when the temperature reaches Curie temperature; voltage detection means 4 that detects the voltage while amplifying the voltage generated on the positive temperature characteristic sensitive resistance 3; and current adjusting means 5 that increases/reduces the charge current to maintain the voltage detected by the voltage detection means 4 at a constant level. The positive temperature characteristic sensitive resistance 3 is disposed in series to a supply path of the charge current being in thermal-contact with the secondary battery 1. Therefore, the voltage detection means 4 detects a voltage generated by the charge current on the positive temperature characteristic sensitive resistance 3 and the voltage according to the changes of the resistance value on the positive temperature characteristic sensitive resistance due to the heat generated by the secondary battery 1. Since the current adjusting means 5 adjusts the charge current, accompanying the charge current adjustment when the secondary battery 1 is heated, the current is reduced and the heat on the secondary battery 1 is reduced. Thus, a charging circuit free from deterioration can be achieved. |
