Patent ID: 8289001
Filing Date: 2012-10-16
Classification: H02J

Abstract:
1. A battery charging circuit comprising: an output transistor that supplies a battery with charging current; first and second transistors, each having a control terminal, which is connected to the control terminal of the other transistor and that of the output transistor, and a current input terminal, which is connected to the current input terminal of the other transistor and that of the output transistor; a first terminal that connects a current output terminal of the first transistor to a first resistor, which determines a charging current in a trickle charge mode; a second terminal that connects a current output terminal of the second transistor to a second resistor, which determines a charging current in a fast charge mode; a selective switch circuit that selectively outputs voltage from the first and second terminals; a first error amplifier that compares an output from the switch circuit with a current restriction reference voltage, which is for restricting current; and a current amount determination unit that determines a gate voltage of the output transistor based on an output of the error amplifier; wherein the first transistor is larger in size than the second transistor.