BATTERY CHARGER FOR PORTABLE ELECTRONIC EQUIPMENT

摘要

There is offered a battery charger for a portable electronic device that has a simple structure and is capable of detecting that the portable electronic device is connected to the battery charger. A first power supply line is connected to a positive terminal (+) of a rechargeable battery, while a ground line is connected to a negative terminal (−) of the rechargeable battery. An output transistor is connected between the first power supply line and a second power supply line. The output transistor is connected to a Vbus terminal of a USB connector through the second power supply line. A controller outputs a voltage of an H level to the Vbus terminal to detect a change in a voltage at the Vbus terminal, and judges whether the portable electronic device is connected to the USB connector based on a result of the detection. The controller turns the output transistor on when the portable electronic device is judged to be connected to the USB connector.