原标题：Wolfson WM2002立体声耳机驱动解决方案

　　Wolfson 公司的WM2002是采用Wolfson myZoneTM环境噪音消(ANC)除技术的立体声耳机驱动器，可采用单端或BTL输出配置，支持模拟播放或语音输入，模拟或数字麦克风。WM2002集成了功率管理，包括DC/DC转换器，电荷泵和LDO稳压器，采用单节AAA电池供电。环境噪音可降低25dB(典型值),降噪带宽(40Hz -4kHz) ，BTL驱动的THD+N可达-80dB。主要用在带ANC的手机，耳机以及蓝牙单声道/立体声手机。本文介绍了WM2002主要特性，方框图，典型应用框图以及推荐外接元件数值和DC1升压转换器和电荷泵外接元件数值。

　　Stereo Headphone Driver with Wolfson myZoneTM Ambient Noise Cancellation

　　The WM2002 is a low power, high quality stereo headphone driver, delivering Wolfson’s patented myZoneTM ambient noise cancellation in a single-ended or BTL (bridge-tied-load) output configuration. The WM2002 supports analogue playback or voice input, and analogue or digital microphone inputs for noisemonitoring microphones.

　　Designed for embedded applications or incorporated within a stand-alone headset or headphone, the Wolfson myZone™ ANC noise cancellation engine performs ambient noise cancellation during a voice call or during music playback.

　　The ambient noise input is supported via single-ended or differential analogue microphone interfaces; digital microphone input is also supported. Up to 10 noise input microphones can be supported at once.

　　The WM2002 provides integrated power management, comprising a DC-DC converter, Charge Pump and LDO Regulators. Many different power supply configurations are thus supported. The entire device can be powered from a single cell AAA battery, or from 2xAAA cells, or from an external regulated supply.

　　System clocking is achieved using an on-chip oscillator. An external clock can be connected directly, if available. The WM2002 is configured using programmable settings stored in an integrated non-volatile memory. The configuration stored in the OTP memory is enabled automatically at start-up. If required, the WM2002 can also be configured using register control accessed using a 2-wire serial control interface.

　　WM2002主要特性：

　　Wolfson myZone™ Ambient Noise Cancellation (ANC)

　　- >30dB (peak), 25dB (typical) ambient noise reduction*

　　- Wide noise cancellation bandwidth (40Hz to 4kHz)*

　　- * depending on acoustic configuration

　　- Multiple banks of ANC coefficients can be programmed to support different operating conditions

　　Audio inputs

　　- Up to 10 analogue or digital microphones

　　- Single-ended or differential analogue microphone input

　　- 2 single-ended or 1 differential line input per channel

　　Headphone driver (LDO4VOUT = 1.8V)

　　- 45mW per channel into 16ohm load

　　- 22mW per channel into 32ohm load

　　- Single-ended or differential (BTL) drive configuration

　　- -80dB THD+N for differential (BTL) drive

　　Integration

　　- On-chip DC-DC boost converter, charge-pump and LDOs

　　- Flexible power supply options, including single cell battery (1 x AAA battery) or (2 x AAA/AAAA)

　　- Internal crystal oscillator

　　Miscellaneous

　　- Monitor pin to select mute / talk-through modes

　　- LED driver

　　- Tone generator for audible status indication

　　- Pop and click noise protection circuit

　　- RFI suppression

　　- 48-pin QFN package (7 x 7 x 0.75mm, 0.5mm pitch)

　　WM2002应用：

　　“Pod-style” stereo ear-buds, headsets, headphones with ANC

　　“Supra-Aural” stereo headphones with ANC

　　Mono/Stereo Bluetooth headsets with ANC

　　图1。WM2002方框图

　　图2。WM2002典型应用框图

　　图3。WM2002推荐外接元件数值

　　图4。WM2002 DC1升压转换器和电荷泵外接元件数值