參數(shù)資料
型號: TPA3008D2PHP
廠商: TEXAS INSTRUMENTS INC
元件分類: 音頻/視頻放大
英文描述: 10 W, 2 CHANNEL, AUDIO AMPLIFIER, PQFP48
封裝: GREEN, PLASTIC, HTQFP-48
文件頁數(shù): 6/31頁
文件大?。?/td> 654K
代理商: TPA3008D2PHP
0 V
12 V
+12 V
Current
OUTP
OUTN
Differential
Voltage
Across
Load
0 V
12 V
+12 V
Current
OUTP
OUTN
Differential
Voltage
Across
Load
Output = 0 V
Output > 0 V
SLOS435C – MAY 2004 – REVISED AUGUST 2010
www.ti.com
Figure 18. The TPA3008D2 Output Voltage and Current Waveforms Into an Inductive Load
Efficiency: LC Filter Required With the Traditional Class-D Modulation Scheme
The main reason that the traditional class-D amplifier needs an output filter is that the switching waveform results
in maximum current flow. This causes more loss in the load, which causes lower efficiency. The ripple current is
large for the traditional modulation scheme, because the ripple current is proportional to voltage multiplied by the
time at that voltage. The differential voltage swing is 2 x VCC, and the time at each voltage is half the period for
the traditional modulation scheme. An ideal LC filter is needed to store the ripple current from each half cycle for
the next half cycle, while any resistance causes power dissipation. The speaker is both resistive and reactive,
whereas an LC filter is almost purely reactive.
The TPA3008D2 modulation scheme has little loss in the load without a filter because the pulses are short and
the change in voltage is VCC instead of 2 x VCC. As the output power increases, the pulses widen, making the
ripple current larger. Ripple current could be filtered with an LC filter for increased efficiency, but for most
applications the filter is not needed.
An LC filter with a cutoff frequency less than the class-D switching frequency allows the switching current to flow
through the filter instead of the load. The filter has less resistance than the speaker, which results in less power
dissipation, therefore increasing efficiency.
Effects of Applying a Square Wave Into a Speaker
Audio specialists have advised for years not to apply a square wave to speakers. If the amplitude of the
waveform is high enough and the frequency of the square wave is within the bandwidth of the speaker, the
square wave could cause the voice coil to jump out of the air gap and/or scar the voice coil. A 250-kHz switching
frequency, however, does not significantly move the voice coil, as the cone movement is proportional to 1/f2 for
frequencies beyond the audio band.
14
Copyright 2004–2010, Texas Instruments Incorporated
Product Folder Link(s): TPA3008D2
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
TPA3008D2PHPG4 功能描述:音頻放大器 10-W Stereo Class-D RoHS:否 制造商:STMicroelectronics 產(chǎn)品:General Purpose Audio Amplifiers 輸出類型:Digital 輸出功率: THD + 噪聲: 工作電源電壓:3.3 V 電源電流: 最大功率耗散: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TQFP-64 封裝:Reel
TPA3008D2PHPR 功能描述:音頻放大器 10-W Stereo Class-D RoHS:否 制造商:STMicroelectronics 產(chǎn)品:General Purpose Audio Amplifiers 輸出類型:Digital 輸出功率: THD + 噪聲: 工作電源電壓:3.3 V 電源電流: 最大功率耗散: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TQFP-64 封裝:Reel
TPA3008D2PHPRG4 功能描述:音頻放大器 10-W Stereo Class-D RoHS:否 制造商:STMicroelectronics 產(chǎn)品:General Purpose Audio Amplifiers 輸出類型:Digital 輸出功率: THD + 噪聲: 工作電源電壓:3.3 V 電源電流: 最大功率耗散: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TQFP-64 封裝:Reel
TPA3009D2PHP 制造商:Texas Instruments 功能描述:
TPA3009D2PHPR 制造商:Texas Instruments 功能描述: