Silabs公司的Si2704/05/06/07是降EMI的数字音频处理D类放大器,集成了功率级,PWM DAC和数字音频处理(DAP),以简化低成本高效率系统的设计. Si270x具有数字输入Delta-Sigma PWM,正在申请专利的降EMI,AM波段无噪音陷波滤波器,能向3欧姆BTL输出2x5W功率,PSRR大于50dB时的效率88%,THD优于0.1%时的动态范围为95dB,主要应用在PMP/MP3坞站,手持消费类电子,有源/无线扬声器,TV和监视器以及TV声卡等.本文介绍了Si2704/05/06/07主要特性, 功能方框图, 典型应用电路图和材料清单,以及多种系统配置图与Si270x-EVB D类放大器开发套件主要特性.
The Si2704/05/06/07 EMI mitigating 2.1 digital audio processing Class D amplifier integrates a power stage, PWM DAC, and digital audio processing (DAP) for simplified, low cost, power efficient system designs in consumer audio electronics. The digital input amplifier features delta-sigma PWM and innovative EMI mitigation technology for producing high-quality audio while effectively managing PWM switching noise for enhanced EMI compliance and AM/FM radio co-existence, while also being GSM/iPhone friendly.
Si2704/05/06/07主要特性:
Digital input Delta-Sigma PWM
Patent-pending EMI mitigation
AM radio band noise-free notch
GSM/iPhone friendly
Wideband PWM carrier spreading
Power stage slew rate control
Power stage feedback for PSR/THD
2x 5 W @ 3 ohm BTL; 2x 3 W @ 8 ohm BTL
88% efficiency with >50 dB PSRR
95 dB dynamic range and <0.1% THD
Stereo PWM DAC line analog outputs
Master/slave I2S w/ 3 inputs & 1 output
Automatic digital audio rate detection
Standard audio rates from 32–192 kHz
Audio activity detector w/ auto-standby
Operates from external XTAL or clock
Buffered master/regulator clock output
Programmable 7 band parametric EQ, dynamic range compressor, tone control
Crossbar input mixer with scaling
Digital tone and alert generation
128 dB volume control in 0.5 dB steps
Multiple low power operating modes
Over-current and over-temperature detection w/ auto recovery
Pop and click free operation
Standard 2-wire control w/ 2 addresses
System flexibility w/ 3 multi-function pins
Dual supply voltage: 2.7–3.6 V main and 4.0–6.6 V power stage
Available in 4x4 24-pin Power QFN and 7x7 48-pin Power eTQFP package
Both Pb-free/RoHS compliant
Si2704/05/06/07应用:
PMP/MP3 docking stations
Portable consumer audio electronics
Table top and portable radios
Active/wireless speakers
TVs and monitors
TV sound bars
图1.Si2704/05/06/07功能方框图
图2.Si2704/05/06/07典型应用电路图
典型应用电路材料清单(BOM):
图3.Si270x PMP坞站系统基本配置图
图4.Si270x 带无线电和数字媒体控制的PMP坞站系统配置图
图5.Si270x立体声双向扬声器系统配置图
图6.Si270x TV声卡系统配置图
Si270x-EVB D类放大器开发套件
Si270x-EVB Class D Amplifier Development Kit
图7.Si270x-EVB D类放大器开发套件外形图
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-EVB kit addresses the entire Si270x family of Class D amplifier products.
The daughter card is populated with the Si2707 Class D amplifier which 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 Ω 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
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