Charging circuit and control method therefor

摘要

A charging circuit includes a power path control unit which switches a first switch connected between a system connection terminal and a battery connection terminal on while not charging, and switches the first switch on and a second switch connected between an external power supply input terminal and the system connection terminal on while charging so as to supply power to a system and charge a battery. A voltage difference between the external power supply input terminal and the battery connection terminal is detected, a current flowing between the external power supply input terminal and the system connection terminal is detected, and it is determined that an external power supply is disconnected based on the detection results of the voltage differences and the current.

主权项

1. A charging circuit comprising:
an external power supply input terminal; a system connection terminal; a battery connection terminal; a first switch connected between the system connection terminal and the battery connection terminal; a second switch connected between the external power supply input terminal and the system connection terminal; a power path control unit configured to linearly control a power supply operation to supply power to a system and a charging operation to charge a battery by switching the first switch on while not charging, and switching the first and the second switches on while charging; a first voltage comparator configured to detect a difference between a voltage at the external power supply input terminal and a voltage at the system connection terminal; a second voltage comparator configured to detect a difference between the voltage at the external power supply input terminal and a voltage at the battery connection terminal; a current detector configured to detect a current flowing between the external power supply input terminal and the system connection terminal; and an external power supply disconnection detection circuit configured to detect a disconnection of an external power supply based on detection results of the respective voltage comparators and detection result of the current detector.