Electronic apparatuses, such as mobile phones and smart phones, have built-in battery cells therein, and for example, alternating current (AC) adapters are connected to the electronic apparatuses to charge the battery cells with AC power supplies. In recent years, as opposed to “contact” charging performed by connecting an AC adapter to an electronic apparatus, “contactless” charging for performing charging using an electromagnetic induction technology, for example, by placing an electronic apparatus on a battery charging stand.
With enhancement in the functionality of electronic apparatuses in recent years, the capacities of battery cells therein are on a growing trend and thus the amounts of time taken for charging the battery cells also tend to increase. In order to reduce the charging time, it is conceivable to increase charging current flowing from a power supply to a battery cell. However, since the current capacities of the battery cell and a charging circuit are limited, it is difficult to significantly increase the charging current.
In that respect, in related art, a technology in which a capacitor and a rechargeable battery are provided side by side and are charged during both contact charging and contactless charging is available to increase the charging speed. Such a technology is disclosed in, for example, International Publication Pamphlet No. 2002/086811.