Patent ID: 8269467
Filing Date: 2012-09-18
Classification: H02J

Abstract:
1. A dual-mode charger circuit to charge a battery, comprising: a first charge circuit connected between a power source and the battery, to provide a first charge path; a second charge circuit connected in parallel with the first charge circuit, to provide a second charge path; a central processing unit connected to the battery, to detect a capacity of the battery and determine whether the detected capacity exceeds a predetermined capacity, and to output a mode control signal according to the determination; and a mode switch circuit connected between the central processing unit and the second charger circuit, to switch the second charger circuit on/off according to the mode control signal; wherein each of the first and second charge circuits comprises: a first resistor; a first transistor comprising a control end connected to the power source via the first resistor, and a first output connected to the power source directly; a second transistor with a control end connected to a second output of the first transistor, a first output connected to the control end of the first transistor, and a second output connected to the battery; and a second resistor connected to the control end of the second transistor; wherein the second transistor and the second resistor form a bias circuit of the first transistor, to provide a bias voltage to the first transistor to turn the first transistor on consistently, when the mode switch circuit switches the second charge circuit off, the battery is charged only through the first charge path under a slow charge mode of the dual-mode charger circuit, and when the mode switch circuit switches the second charge circuit on, the battery is charged through both the first charge path and the second charge path under a quick charge mode of the dual-mode charger circuit.