Microphone device, telephone device, and decoupling circuit

A microphone device, comprising:

• an audio source;
• a first capacitor, wherein a first terminal of the first capacitor is coupled to a first terminal of the audio source;
• a first resistor, wherein a first terminal of the first resistor is coupled to a second terminal of the first capacitor, and a second terminal of the first resistor is coupled to a second terminal of the audio source;
• and
• a switch, wherein a first terminal of the switch is coupled to the second terminal of the first capacitor and the first terminal of the first resistor, and a second terminal of the switch is coupled to the second terminal of the audio source,
• wherein the first capacitor and the first resistor are configured to absorb noise generated by the switch during switching, and
• a first output terminal of the microphone device provides an audio signal according to one of the first terminal and the second terminal of the audio source,
• wherein when the audio source is a differential input, the microphone device further comprises:
• a second capacitor, wherein a first terminal of the second capacitor is coupled to one of the first terminal and the second terminal of the audio source, and a second terminal of the second capacitor is coupled to a first output terminal;
• a second resistor, wherein a first terminal of the second resistor is coupled to a bias voltage, and a second terminal of the second resistor is coupled to the one of the first terminal and the second terminal of the audio source;
• a third capacitor, wherein a first terminal of the third capacitor is coupled to the other one of the first terminal and the second terminal of the audio source, and a second terminal of the third capacitor is coupled to a second output terminal;
• and
• a third resistor, wherein a first terminal of the third resistor is coupled to a reference voltage terminal, and a second terminal of the third resistor is coupled to the other one of the first terminal and the second terminal of the audio source and the first terminal of the third capacitor.

A telephone device, comprising:

• a microphone device;
• and
• a telephone set device, coupled to the microphone device to receive an audio signal,
• wherein the microphone device comprises:
• an audio source;
• a first capacitor, wherein a first terminal of the first capacitor is coupled to a first terminal of the audio source;
• a first resistor, wherein a first terminal of the first resistor is coupled to a second terminal of the first capacitor, and a second terminal of the first resistor is coupled to a second terminal of the audio source;
• and
• a switch, wherein a first terminal of the switch is coupled to the second terminal of the first capacitor and the first terminal of the first resistor, and a second terminal of the switch is coupled to the second terminal of the audio source,
• wherein a first output terminal of the microphone device provides an audio signal according to one of the first terminal and the second terminal of the audio source, and
• the first capacitor and the first resistor are configured to absorb noise generated by the switch during switching,
• wherein when the audio source is a differential input, the telephone device further comprises:
• a second capacitor, wherein a first terminal of the second capacitor is coupled to one of the first terminal and the second terminal of the audio source, and a second terminal of the second capacitor is coupled to a first output terminal;
• a second resistor, wherein a first terminal of the second resistor is coupled to a bias voltage, and a second terminal of the second resistor is coupled to the one of the first terminal and the second terminal of the audio source;
• a third capacitor, wherein a first terminal of the third capacitor is coupled to the other one of the first terminal and the second terminal of the audio source, and a second terminal of the third capacitor is coupled to a second output terminal;
• and
• a third resistor, wherein a first terminal of the third resistor is coupled to a reference voltage terminal, and a second terminal of the third resistor is coupled to the other one of the first terminal and the second terminal of the audio source and the first terminal of the third capacitor.