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參數(shù)資料
| 型號(hào)： | LM4671 |
| 廠商： | National Semiconductor Corporation |
| 元件分類： | 音頻放大器 |
| 英文描述： | Filterless High Efficiency 2.5W Switching Audio Amplifier |
| 中文描述： | 濾波2.5W的高效率開(kāi)關(guān)音頻放大器 |
| 文件頁(yè)數(shù)： | 10/18頁(yè) |
| 文件大?。?/td> | 969K |
| 代理商： | LM4671 |
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Typical Performance Characteristics
(Continued)
Gain vs Supply Voltage
R
in
= 150k
Supply Current vs Supply Voltage
R
L
= 15μH+8
+15μH
20107319
20107320
Shutdown Current vs Supply Voltage
R
L
= 15μH+8
+15μH
20107321
Application Information
GENERAL AMPLIFIER FUNCTION
The LM4671 features a filterless modulation scheme. The
differential outputs of the device switch at 300kHz from V
to GND. When there is no input signal applied, the two
outputs (V
1 and V
2) switch with a 50% duty cycle, with
both outputs in phase. Because the outputs of the LM4671
are differential, the two signals cancel each other. This re-
sults in no net voltage across the speaker, thus there is no
load current during an idle state, conserving power.
With an input signal applied, the duty cycle (pulse width) of
the LM4671 outputs changes. For increasing output volt-
ages, the duty cycle of V
O
1 increases, while the duty cycle of
V
O
2 decreases. For decreasing output voltages, the con-
verse occurs, the duty cycle of V
O
2 increases while the duty
cycle of V
1 decreases. The difference between the two
pulse widths yields the differential output voltage.
POWER DISSIPATION AND EFFICIENCY
In general terms, efficiency is considered to be the ratio of
useful work output divided by the total energy required to
produce it with the difference being the power dissipated,
typically, in the IC. The key here is “useful” work. For audio
systems, the energy delivered in the audible bands is con-
sidered useful including the distortion products of the input
signal.
Sub-sonic
(DC)
and
(
>
22kHz) are not useful. The difference between the power
flowing from the power supply and the audio band power
being transduced is dissipated in the LM4671 and in the
transducer load. The amount of power dissipation in the
LM4671 is very low. This is because the ON resistance of the
switches used to form the output waveforms is typically less
than 0.25
. This leaves only the transducer load as a po-
tential "sink" for the small excess of input power over audio
super-sonic
components
L
www.national.com
10
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LM4671_07 | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:Filterless High Efficiency 2.5W Switching Audio Amplifier |
| LM4671_08 | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:Filterless High Efficiency 2.5W Switching Audio Amplifier |
| LM4671ITL | 制造商:Texas Instruments 功能描述:Audio Amp Speaker 1-CH Mono 2.5W Class-AB 9-Pin uSMD T/R 制造商:Texas Instruments 功能描述:IC AMP FILTERLESS 2.5W SMD 4671 |
| LM4671ITL/NOPB | 功能描述:音頻放大器 Filterless Hi Eff 2.5W Swtch Audio Amp 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 |
| LM4671ITLBD | 功能描述:BOARD EVALUATION LM4671ITL RoHS:否 類別:編程器，開(kāi)發(fā)系統(tǒng) >> 評(píng)估板 - 音頻放大器 系列:Boomer® 產(chǎn)品培訓(xùn)模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:1 系列:- |
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