參數(shù)資料
型號(hào): TPA2005D1DGNR
廠商: TEXAS INSTRUMENTS INC
元件分類(lèi): 音頻/視頻放大
英文描述: 1.45 W, 1 CHANNEL, AUDIO AMPLIFIER, PDSO8
封裝: GREEN, PLASTIC, MSOP-8
文件頁(yè)數(shù): 10/32頁(yè)
文件大小: 1128K
代理商: TPA2005D1DGNR
0 V
–5 V
+5 V
Current
OUT+
OUT–
Differential
Voltage
Across
Load
0 V
–5 V
+5 V
Current
OUT+
OUT–
Differential
Voltage
Across
Load
Output = 0 V
Output > 0 V
Efficiency: Why You Must Use a Filter With the Traditional Class-D Modulation Scheme
Effects of Applying a Square Wave Into a Speaker
SLOS369F – JULY 2002 – REVISED JULY 2008............................................................................................................................................................... www.ti.com
Figure 40. The TPA2005D1 Output Voltage and Current Waveforms Into an Inductive Load
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 × VDD 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 TPA2005D1 modulation scheme has little loss in the load without a filter because the pulses are short and
the change in voltage is VDD instead of 2 × VDD. 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 that results in less power
dissipated, which increases efficiency.
If the amplitude of a square wave is high enough and the frequency of the square wave is within the bandwidth
of the speaker, a 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, is not significant because the speaker cone movement is proportional to
1/f2 for frequencies beyond the audio band. Therefore, the amount of cone movement at the switching frequency
is small. However, damage could occur to the speaker if the voice coil is not designed to handle the additional
power. To size the speaker for added power, the ripple current dissipated in the load needs to be calculated by
subtracting the theoretical supplied power, PSUP THEORETICAL, from the actual supply power, PSUP, at maximum
output power, POUT. The switching power dissipated in the speaker is the inverse of the measured efficiency,η
MEASURED, minus the theoretical efficiency,η THEORETICAL.
18
Copyright 2002–2008, Texas Instruments Incorporated
Product Folder Link(s): TPA2005D1
相關(guān)PDF資料
PDF描述
TPA2005D1DGN 1.45 W, 1 CHANNEL, AUDIO AMPLIFIER, PDSO8
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TPA2005D1DGNG4 1.45 W, 1 CHANNEL, AUDIO AMPLIFIER, PDSO8
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
TPA2005D1DGNRG4 功能描述:音頻放大器 Mono Fully Diff Filter-Free Class-D RoHS:否 制造商:STMicroelectronics 產(chǎn)品:General Purpose Audio Amplifiers 輸出類(lèi)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
TPA2005D1DGNRQ1 功能描述:音頻放大器 1.4W Class D Audio Power Amp RoHS:否 制造商:STMicroelectronics 產(chǎn)品:General Purpose Audio Amplifiers 輸出類(lèi)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
TPA2005D1DRBQ1 功能描述:音頻放大器 1.4-W Mono Class-D Aud Power Amplifier RoHS:否 制造商:STMicroelectronics 產(chǎn)品:General Purpose Audio Amplifiers 輸出類(lèi)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
TPA2005D1DRBR 功能描述:音頻放大器 Mono Fully Diff Filter-Free Class-D RoHS:否 制造商:STMicroelectronics 產(chǎn)品:General Purpose Audio Amplifiers 輸出類(lèi)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
TPA2005D1DRBR 制造商:Texas Instruments 功能描述:IC AUDIO AMP DIFF CLASS D SON 制造商:Texas Instruments 功能描述:IC, AUDIO AMP, DIFF CLASS D, SON 制造商:Texas Instruments 功能描述:IC, AUDIO AMP, DIFF CLASS D, SON; Amplifier Class:D; No. of Channels:1; Output Power:1.4W; Supply Voltage Range:2.5V to 5.5V; Amplifier Case Style:QFN; No. of Pins:8; Load Impedance:8ohm; Operating Temperature Min:-40C; Operating ;RoHS Compliant: Yes