参数资料
型号: TPA2000D1PWRG4
厂商: TEXAS INSTRUMENTS INC
元件分类: 音频/视频放大
英文描述: 2 W, 1 CHANNEL, AUDIO AMPLIFIER, PDSO16
封装: GREEN, PLASTIC, TSSOP-16
文件页数: 23/23页
文件大小: 500K
代理商: TPA2000D1PWRG4
www.ti.com
APPLICATION INFORMATION
ELIMINATING THE OUTPUT FILTER WITH THE TPA2000D1
EFFECT ON AUDIO
TRADITIONAL CLASS-D MODULATION SCHEME
O V
–5 V
+5 V
Current
OUTP
Differential Voltage
Across Load
OUTN
TPA2000D1 MODULATION SCHEME
TPA2000D1
SLOS328F – JUNE 2000 – REVISED MARCH 2004
This section explains why the user can eliminate the output filter with the TPA2000D1.
The class-D amplifier outputs a pulse-width modulated (PWM) square wave, which is the sum of the switching
waveform and the amplified input audio signal. The human ear acts as a band-pass filter such that only the
frequencies between approximately 20 Hz and 20 kHz are passed. The switching frequency components are
much greater than 20 kHz, so the only signal heard is the amplified input audio signal.
The traditional class-D modulation scheme, which is used in the TPA005Dxx family, has a differential output
where each output is 180 degrees out of phase and changes from ground to the supply voltage, VDD. Therefore,
the differential prefiltered output varies between positive and negative VDD, where filtered 50% duty cycle yields
0 V across the load. The traditional class-D modulation scheme with voltage and current waveforms is shown in
Figure 9. Even at an average of 0 V across the load (50% duty cycle), the current to the load is high, causing
high loss, and a high supply current.
Figure 9. Traditional Class-D Modulation Scheme Output Voltage and Current Waveforms Into an
Inductive Load With No Input
The TPA2000D1 uses a modulation scheme that still has each output switching from 0 to the supply voltage.
However, OUTP and OUTN are now in phase with each other with no input. The duty cycle of OUTP is greater
than 50% and OUTN is less than 50% for positive voltages. The duty cycle of OUTP is less than 50% and OUTN
is greater than 50% for negative voltages. The voltage across the load sits at 0 V throughout most of the
switching period greatly reducing the switching current, which reduces any I2R losses in the load.
9
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相关代理商/技术参数
参数描述
TPA2000D1-Q1 制造商:TI 制造商全称:Texas Instruments 功能描述:2-W FILTERLESS MONO CLASS-D AUDIO POWER AMPLIFIER
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TPA2000D1TPWRQ1 功能描述:音频放大器 Auto Cat Mono Filter Free Class D RoHS:否 制造商:STMicroelectronics 产品:General Purpose Audio Amplifiers 输出类型:Digital 输出功率: THD + 噪声: 工作电源电压:3.3 V 电源电流: 最大功率耗散: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:TQFP-64 封装:Reel
TPA2000D2 制造商:TI 制造商全称:Texas Instruments 功能描述:2-W FILTERLESS STEREO CLASS-D AUDIO POWER AMPLIFIER
TPA2000D2_07 制造商:TI 制造商全称:Texas Instruments 功能描述:2-W FILTERLESS STEREO CLASS-D AUDIO POWER AMPLIFIER