Patent ID: 6566843
Filing Date: 2003-05-20
Classification: H02J

Abstract:
A DC power source unit used as a power source of an electrically powered tool and having a charging function for charging a battery pack used as an alternative power source of the tool, the tool having a power switch, the DC power source unit comprising:a switching power source for implementing an AC-DC conversion and providing a DC power; a battery pack connecting portion for connecting the battery pack to charge with the DC power provided from the switching power source; an adapter for supplying the DC power provided from the switching power source to the tool; a power source output controller for controlling the DC power provided from the switching power source in accordance with the DC power supplied to the tool and to the battery pack; a power output switching circuit for switching between supplying the DC power to the tool through the adapter and charging the battery pack; and a trigger detector for detecting that the power switch of the tool is turned ON and outputting an ON signal indicative of ON of the power switch to the power output switching circuit, wherein in response to the ON signal, the power output switching circuit instantaneously allows the DC power to be supplied to the tool and prohibits the battery pack from being charged.