Charger for electronic device, electronic device, and charging method

An electronic device capable of using a rechargeable battery, the electronic device comprising:

• a charger which charges the rechargeable battery that is arranged in the electronic device, the charger including:
• a detection unit which detects connection of another electronic device to the electronic device through a communication cable including a power supply line;
• a charging unit which charges the rechargeable battery with power supply voltage from the power supply line of the communication cable;
• a measurement unit which acquires a measurement value indicating a degree of a voltage drop of the power supply voltage occurred when the charging unit performs charging;
• and
• a control unit which instructs a charging current value for charging the rechargeable battery with the charging unit;
• wherein when the detection unit detects connection of the other electronic device, the control unit monitors the measurement value obtained by the measurement unit while instructing the charging unit to increase the charging current value from an initial current value and determines the charging current value based on the monitored measurement value.

A method for charging a rechargeable battery arranged in an electronic device, the method comprising:

• detecting, by the electronic device, connection of another electronic device to the electronic device through a communication cable including a power supply line;
• starting, by the electronic device, charging of the rechargeable battery using a power supply voltage from the power supply line of the communication cable;
• acquiring, by the electronic device, a measurement value indicating a degree of a voltage drop of the power supply voltage occurred during charging;
• and
• determining, by the electronic device, a charging current value of the rechargeable battery based on the measurement value;
• wherein said determining includes:
• monitoring the measurement value during the charging while increasing the charging current value from an initial current value;
• and
• updating the charging current value based on the monitored measurement value.