Patent ID: 8248028

Claim:
A device housing a battery and charging pad comprising: a charging pad provided with a power supply coil; and a device housing a battery containing an induction coil that magnetically couples with the power supply coil, wherein the internal battery in the device housing a battery is charged with power transmitted from the power supply coil to the induction coil, wherein the charging pad comprises: a case having a charging region where a device housing a battery can be placed in a removable manner; an AC power source connected to the power supply coil; a moving mechanism that moves the power supply coil to a position in close proximity to the induction coil; and a position detection controller that determines the position of the device housing a battery placed on the charging region and controls the moving mechanism to move the power supply coil close to the induction coil of the device housing a battery; wherein the position detection controller comprises: position detection coils fixed to a top plate; a detection signal generating circuit that supplies position detection signals to the position detection coils; a receiving circuit that receives echo signals output from the induction coil to the position detection coils due to excitation of the induction coil by position detection signals supplied to the position detection coils from the detection signal generating circuit; and a discrimination circuit that determines induction coil position from the echo signals received by the receiving circuit; wherein the device housing a battery comprises: a rectifying circuit connected to the induction coil that converts AC induced in the induction coil to DC to supply the internal battery with charging power; a series capacitor connected in series with the induction coil to input induction coil AC to the rectifying circuit; a parallel capacitor connected in parallel with the induction coil 51 ; and a switching circuit that switches the connection of the series capacitor, the parallel capacitor, and the induction coil, and wherein when the position detection controller issues position detection signals, the parallel capacitor is connected to the induction coil by the switching circuit; when power is transmitted from the power supply coil to the induction coil, the parallel capacitor is disconnected from the induction coil, and induction coil AC is output to the rectifying circuit through the series capacitor.