基于Si270x降EMI音頻D類放大技術

本文介紹了Si2704/05/06/07主要特性, 功能方框圖, 典型應用電路圖和材料清單,以及多種系統配置圖與Si270x-EVB D類放大器開發套件主要特性.

Silabs公司的Si2704/05/06/07是降EMI的數字音頻處理D類放大器,集成了功率級,PWM DAC和數字音頻處理(DAP),以簡化低成本高效率系統的設計. Si270x具有數字輸入Delta-Sigma PWM,正在申請專利的降EMI,AM波段無噪音陷波濾波器,能向3歐姆BTL輸出2x5W功率,PSRR大于50dB時的效率88%,THD優于0.1%時的動態范圍為95dB,主要應用在PMP/MP3塢站,手持消費類電子,有源/無線揚聲器,TV和監視器以及TV聲卡等.

Si2704/05/06/07應用:

PMP/MP3 docking stations

Portable consumer audio electronics

Table top and portable radios

Active/wireless speakers

TVs and monitors

TV sound bars

圖1.Si2704/05/06/07功能方框圖

圖2.Si2704/05/06/07典型應用電路圖
典型應用電路材料清單(BOM):


圖3.Si270x PMP塢站系統基本配置圖

圖4.Si270x 帶無線電和數字媒體控制的PMP塢站系統配置圖

圖5.Si270x立體聲雙向揚聲器系統配置圖

圖6.Si270x TV聲卡系統配置圖

Si270x-EVB D類放大器開發套件

Si270x-EVB Class D Amplifier Development Kit

圖7.Si270x-EVB D類放大器開發套件外形圖

The Si270x Class D amplifier EVB consists of a baseboard and a daughter card.The baseboard is common and shared among all the Si270x 5 W per channel Class D audio amplifier daughter cards. The Si270x-EVBkit addresses the entire Si270x family ofClass D amplifier products.

The daughter card is populated with the Si2707 Class D amplifierwhich provides the following:

EMI mitigation

Volume and tone controls

EQ and Dynamic Range Compressor DSP functions

Tunable noise-free notch for AM radio coexistence

The Si270x Class D amplifier EVB is supported by a full function graphical user interface (GUI) that runs on a standard PC and is connected to the EVB via USB.The baseboard includes the Si4730 AM/FM tuner, a stereo analog input, as well as an optical SPDIF input for digital audio sources.The daughter card also includes the required output filtering network.Speakers with impedances of 4 ? and larger may be directly driven from this board; a separate line level output is provided.

The Si270x-EVB Class D Amplifier development kit includes:

Si270x Evaluation Board

External power supply

AM/FM adapter card and antennas cable

Audio cable

Documentation and software CD