ELECTRONIC DEVICE, ELECTRONIC DEVICE TO BE CHARGED AND METHOD OF CONTROLLING ELECTRONIC DEVICES

An electronic unit for charging a unit to be charged having an accumulator section which can be repeatedly charged has a charging section for charging the accumulator section according to a charging control signal and a charging control section. The charging control section monitors a battery voltage (or a charging current), and maintains an effective charging period per unit time for a long term when the battery voltage (or the charging current) of an accumulator battery is lower than a limit voltage (or the charging current corresponding to the limit voltage) selected in advance. After the battery voltage (or the charging current) reaches the limit voltage (or the charging current corresponding to the limit voltage), however, the charging control section reduces the effective charging period per unit time.