Volume adjustment circuit with automatic gain control and electronic device using same

An electronic device, comprising:

• a voltage adjustment circuit;
• an audio source electrically coupled to an audio input terminal of the voltage adjustment circuit, the audio source being configured for providing an input audio signal to the voltage adjustment circuit;
• and
• a speaker electrically coupled to an audio output terminal of the voltage adjustment circuit, the speaker being configured for transforming an output audio signal of the volume adjustment circuit into an audible signal;
• wherein the volume adjustment circuit comprises:
• an amplification circuit, configured for amplifying the audio signal to generate the output audio signal, and outputting the second audio signal to the speaker via the audio output terminal;
• a control circuit electrically coupled to the audio output terminal, the control circuit being configured for generating a control signal based on the output audio signal;
• and
• an adjustment circuit electrically coupled to the control circuit, the adjustment circuit being configured for adjusting an amplitude of the audio signal inputted to the amplification circuit based on the control circuit.