| 摘要 |
PURPOSE: A charging circuit is provided to allow a user to recognize complete charging of battery or existence of battery during charging of battery, while reducing weight of the charger by incorporating the charging circuit into hand-held communications device. CONSTITUTION: A charging circuit comprises a battery(50); a battery existence judging unit(20) for judging whether the battery exists, and reporting charging current supply to a mobile station modem chip(60); a switching transistor(Q4) for controlling charging current supply to the battery; a constant voltage processing unit(30) for regulating the DC voltage into constant voltage for use as the charging current; a differential amplification and voltage detection unit(40) for charging the battery by sensing the constant voltage, or reporting the charged state of the battery to the mobile station modem chip; a charge on/off control unit(10) for controlling battery charging; and the mobile station modem chip for generating charging on/off control signals to the charge on/off control unit in accordance with the existence or absence of the battery.
|
