TI 公司的TAS5707是20W高效數(shù)字音頻功率放大器,能驅(qū)動橋式連接的立體聲揚聲器.模擬音頻輸入/輸出, 支持8-kHz 到48-kHz取樣頻率,能從18V的電源向8歐姆負載提供20W功率. TAS5707的工作電壓從8V到24V,采用高效的D類放大器,不需要散熱器.本文介紹了TAS5707的主要特性,方框圖以及TAS5707評估板的主要特性,電路圖以及所用材料費清單.
The TAS5707 is a 20-W, efficient, digital audio power amplifier for driving stereo bridge-tied speakers. One serial data input allows processing of up to two discrete audio channels and seamless integration to most digital audio processors and MPEG decoders. The device accepts a wide range of input data and data rates. A fully programmable data path routes these channels to the internal speaker drivers.
The TAS5707 is a slave-only device receiving all clocks from external sources. The TAS5707 operates with a PWM carrier between 384-kHz switching rate and 352-KHz switching rate depending on the input sample rate. Oversampling combined with a fourth-order noise shaper provides a flat noise floor and excellent dynamic range from 20 Hz to 20 kHz.
主要特性:
Audio Input/Output:
20-W Into an 8-Ω Load From an 18-V Supply
Wide PVDD Range, From 8 V to 24 V
Efficient Class-D Operation Eliminates Need for Heatsinks
Requires Only 3.3 V and PVDD
One Serial Audio Input (Two Audio Channels)
Supports 8-kHz to 48-kHz Sample Rate (LJ/RJ/I2S)
Audio/PWM Processing:
Independent Channel Volume Controls With 24-dB to Mute
Soft Mute (50% Duty Cycle)
Programmable Dynamic Range Control
14 Programmable Biquads for Speaker EQ and Other Audio Processing Features
Programmable Coefficients for DRC Filters
DC Blocking Filters
General Features:
Serial Control Interface Operational Without MCLK
Factory-Trimmed Internal Oscillator for automatic rate detection
Surface Mount, 48-PIN, 7-mm × 7-mm HTQFP Package
Thermal and Short-Circuit Protection
Benefits:
EQ: Speaker Equalization Improves Audio Performance
DRC: Dynamic Range Compression. Can Be Used As Power Limiter. Enables Speaker Protection, Easy Listening, Night-Mode Listening.
Autobank Switching: Preload Coefficients for Different Sample Rates. No Need to Write new Coefficients to the Part When Sample Rate Changes.
Autodetect: Automatically Detects Sample-Rate Changes. No Need for External Microprocessor Intervention
圖1.TAS5707方框圖
圖2.TAS5707功率級功能方案圖
評估板的主要特性:
AS5707EVM (TAS5709EVM) and MC57xxPSIA Features
Channel evaluation module design
Self-contained protection systems and control pins
USB interface
Standard I2S data input using optical or coaxial inputs
Analog input through analog-to-digital converter
Subwoofer connection—the PWM terminal provides the PWM signal and power to an external subwoofer board
Double-sided, plated-through PCB, 1-oz copper, 2 mm
Access to control signal gain and data format through EVM-software GUI
圖3.TAS5709EVM PCB外形圖
圖4.完整的系統(tǒng)和EVM信號流程概圖
圖5.簡化的應(yīng)用框圖
圖6.TAS5707評估板電路圖
TAS5707EVM材料清單(BOM):
TAS5709EVM材料清單(BOM):
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