Abstract: An electronic device includes a battery pack, a charging circuit that charges the battery pack, a load device that operates with a power of the battery pack, a voltage sensor that detects a charge voltage and a discharge voltage of the battery pack, a current sensor that detects a charge current and a discharge current of the battery pack, and a control circuit. The control circuit calculates an internal resistance of the battery pack based on the charge voltage and the charge current, calculates an allowable power indicating a maximum power that is able to be acquired from the battery pack by the load device based on the discharge voltage, the discharge current, and the internal resistance, and sends a control signal to the load device to cause the load device to operate with a power less than or equal to the allowable power.

Abstract: An electronic device includes a first switching circuit switching a power feed path between a first path for supplying first power and a second path for supplying second power, and a step-up/down circuit changing a voltage of the second power. The first switching circuit switches the power feed path to the first path when a voltage of the first path is higher than a voltage of the second path, and switches the power feed path to the second path when a voltage of the second path is higher than a voltage of the first path. The step-up/down circuit makes the voltage of the second power lower than a voltage of the first power when the first power is larger than the second power, and makes the voltage of the second power higher than the voltage of the first power when the second power is larger than the first power.