Patent ID: 9325191
Filing Date: 2016-04-26
CPC Classification: H01M,H02J,H02M,Y02B,Y02E

Claim Text:
1. A charger comprising: a power source control circuit that controls charging of a battery that supplies electric power to an electric power tool; a microcomputer that operates the power source control circuit; and a constant voltage power source circuit that supplies electric power to the microcomputer and the power source control circuit, wherein: the constant voltage power source circuit is configured to control electric power supplied to the microcomputer by a pulse width modulation control such that the voltage applied to the microcomputer becomes a predetermined voltage; the microcomputer is configured to output in a time sequence, to the constant voltage power source circuit, a continuous signal by which the constant voltage power source circuit continuously performs the pulse width modulation control, and an intermittent signal by which the constant voltage power source circuit intermittently performs the pulse width modulation control such that the constant voltage power source circuit controls the voltage applied to the microcomputer between a minimum voltage that is required to drive the microcomputer and an operation voltage of the microcomputer; the power source control circuit is configured to control charging when the power source control circuit receives a charging permission signal from the microcomputer; and the microcomputer is configured to output the continuous signal to the constant voltage power source circuit when the microcomputer outputs the charging permission signal to the power source control circuit, and further wherein when the microcomputer stops outputting the charging permission signal to the power source control circuit, the microcomputer is configured to output the intermittent signal to the constant voltage power source circuit and also configured to stop electric power from the constant voltage power source circuit to the power source control circuit.