REGULATOR, BATTERY-CHARGING DEVICE, AND BATTERY-CHARGING METHOD

To provide a regulator capable of more appropriately preventing the voltage of a battery from increasing beyond a full-charge voltage during a battery chattering. [Solution] A regulator 1 includes a rectifying circuit 2, a first battery detecting circuit 3, a first full-charge detecting circuit 4, a first differentiating circuit 5 having a fifth resistor r5 connected between a first terminal T1 and one end of a first capacitor C1 and a second capacitor connected in series with the fifth resistor r5 between the first terminal T1 and one end of the first capacitor C1, and a first driving circuit DR that controls the rectifying circuit 2 to rectify an alternating current according to output of an alternating-current generator ACG and controls the rectifying circuit 2 to operate or stop according to signal at one end of a first battery connecting switch element SW1.