Charging system and method for electronic device controlled by audio output

A charging system for an electronic device controlled by audio output, applicable for controlling an external charging power supply to charge the electronic device, comprising:

• an electric quantity detection software, running on the electronic device, for generating a first audio signal indicating a message of performing a charging operation when an electric quantity of the electronic device is detected to be lower than a first amount, or generating a second audio signal indicating a message of stopping the charging operation when the electric quantity is detected to be higher than a second amount, the first audio signal and the second audio signal are formed by encoding the message of performing the charging operation and the message of stopping the charging operation by an encoding software running on the electronic device;
• an audio output interface, disposed on the electronic device, for outputting the first audio signal or the second audio signal;
• a decoding device, connected to the audio output interface, for receiving the first audio signal and controlling the external charging power supply to perform the charging operation, or for receiving the second audio signal and controlling the external charging power supply to stop the charging operation;
• and
• a relay, connected to the decoding device, and controlled by the decoding device, for turning on the external charging power supply to charge the electronic device or turning off the external charging power supply to stop charging the electronic device.