3 交流耦合（電容器）輸出配置的示例

AVDD = 3.3/3.0/1.8V
Mic_bias = 2.75/2.5/1.375V
Ref = VSS = 0V

• 插入前，設(shè)置 Bias = DVDD = 2V
  $Insertion detected: Mic\_detect<Bias *\frac{22}{25}+Ref=2*\frac{22}{25}+0=1.76$
  $No Insertion : Mic\_detect>Bias *\frac{22}{25}+Ref=2*\frac{22}{25}+0=1.76$
• 耳機(jī)類型檢測(cè)，設(shè)置 Bias = Mic_bias = 3.3V
  $Headset with MIC: Mic\_detect>Bias *\frac{11}{100}+Ref=3.3*\frac{11}{100}+0=0.363$
  $Headset without MIC: Mic\_detect<Bias *\frac{11}{100}+Ref=3.3*\frac{11}{100}+0=0.363$
• 按鈕按下檢測(cè)，設(shè)置 Bias = Mic_bias = 3.3V
  僅當(dāng)檢測(cè)到帶麥克風(fēng)的耳機(jī)時(shí)，按鈕按下檢測(cè)才會(huì)激活。
  $No botton push: Mic\_detect>Bias *\frac{11}{100}+Ref=3.3*\frac{11}{100}+0=0.363$
  $Push botton detected: Mic\_detect <Bias *\frac{11}{100}+Ref=3.3*\frac{11}{100}+0=0.363$

• 耳機(jī)拔出檢測(cè)，設(shè)置 Bias = Mic_bias = 3.3V