Patent ID: 8249272

Claim:
An audio playback apparatus processing an audio signal, providing an output signal to a speaker or an earphone connected to a phone-jack, and comprising: a clock generating module generating a clock signal; a processing module coupled to the clock generating module, processing the audio signal to generate a processed signal according to a clock signal generated by the clock generating module; an amplifier module coupled to the processing module and amplifying the processed signal to generate an output signal; a detecting module coupled to the amplifier module, the speaker, and the phone-jack to detect whether the earphone is plugged in the phone-jack; wherein if the earphone is plugged in the phone-jack, the amplifier module provides the output signal to the earphone, and if not, the amplifier module provides the output signal to the speaker; and wherein the detecting module comprises a voltage source, a first resistor coupled to the voltage source, a second resistor coupled to the first resistor and the phone-jack, and a logic unit comprising a first input terminal, a second input terminal and an output terminal, wherein the first input terminal is coupled to the first and second resistors, the second input terminal is coupled to the amplifier module, and the logic unit performs logic computation according to input signals from the first and second input terminals and generates a control signal at the output terminal based on the logic computation.