Patent ID: 7649343
Filing Date: 2010-01-19
Classification: H01M,H02J,Y02E

Abstract:
1. A charge control circuit for controlling charging operation of a transistor configured to supply a charge current to a secondary battery, the circuit comprising: a battery connector terminal configured to electrically connect the charge control circuit with the secondary battery; a charge current detector provided between a drain of the transistor and the secondary battery and configured to detect a value of the charge current supplied from the transistor to the secondary battery; a voltage comparator coupled to the battery connector terminal and configured to detect a value of a battery voltage at the battery connector terminal and compare the value of the battery voltage with a reference voltage value to generate a comparison result, the reference voltage value comprising a first reference voltage value; and a controller coupled to the battery connector terminal, the charge current detector, and the voltage comparator and configured to turn off the transistor before starting the charging operation, start a charge start wait time after the transistor is turned off while keeping the off state of the transistor, determine whether the value of the battery voltage during the charge start wait time is equal to or greater than the first reference voltage value based on the comparison result to generate a first determination result, and control the on or off state of the transistor after the charge start wait time according to the first determination result, wherein the controller keeps the off state of the transistor after the charge start wait time when the first determination result indicates that the value of the battery voltage during the charge start wait time is less than the first reference voltage value, and the controller turns on the transistor to start the charging operation after the charge start wait time when the first determination result indicates that the value of the battery voltage during the charge start wait time is equal to or greater than the first reference voltage value.