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參數資料
| 型號： | TPA6021A4N |
| 廠商： | TEXAS INSTRUMENTS INC |
| 元件分類： | 音頻控制 |
| 英文描述： | 2 CHANNEL(S), VOLUME CONTROL CIRCUIT, PDIP20 |
| 封裝： | ROHS COMPLIANT, PLASTIC, MS001-AD, DIP-20 |
| 文件頁數： | 11/25頁 |
| 文件大小： | 1823K |
| 代理商： | TPA6021A4N |
www.ti.com
f
(c) +
1
2 p R
L CC
(6)
RL
C(C)
VO(PP)
VDD
-3 dB
fc
SINGLE-ENDED OPERATION
BTL AMPLIFIER EFFICIENCY
TPA6021A4
SLOS465 – JUNE 2005
In a typical computer sound channel operating at 5 V, bridging raises the power into an 8-
speaker from a
singled-ended (SE, ground reference) limit of 250 mW to 1 W. In sound power that is a 6-dB improvement, which
is loudness that can be heard. In addition to increased power there are frequency response concerns. Consider
the single-supply SE configuration shown in Figure 27. A coupling capacitor is required to block the dc offset
voltage from reaching the load. These capacitors can be quite large (approximately 33 F to 1000 F), so they
tend to be expensive, heavy, occupy valuable PCB area, and have the additional drawback of limiting
low-frequency performance of the system. This frequency limiting effect is due to the high-pass filter network
created with the speaker impedance and the coupling capacitance and is calculated with Equation 6.
For example, a 68-F capacitor with an 8-
speaker would attenuate low frequencies below 293 Hz. The BTL
configuration cancels the dc offsets, which eliminates the need for the blocking capacitors. Low-frequency
performance is then limited only by the input network and speaker response. Cost and PCB space are also
minimized by eliminating the bulky coupling capacitor.
Figure 27. Single-Ended Configuration and Frequency Response
Increasing power to the load does carry a penalty of increased internal power dissipation. The increased
dissipation is understandable considering that the BTL configuration produces 4x the output power of the SE
configuration. Internal dissipation versus output power is discussed further in the crest factor and thermal
considerations section.
In SE mode (see Figure 27), the load is driven from the primary amplifier output for each channel (OUT+).
The amplifier switches single-ended operation when the SE/BTL terminal is held high. This puts the negative
outputs in a high-impedance state, and effectively reduces the amplifier's gain by 6 dB.
Class-AB amplifiers are inefficient. The primary cause of these inefficiencies is voltage drop across the output
stage transistors. There are two components of the internal voltage drop. One is the headroom or dc voltage
drop that varies inversely to output power. The second component is due to the sinewave nature of the output.
The total voltage drop can be calculated by subtracting the RMS value of the output voltage from VDD. The
internal voltage drop multiplied by the RMS value of the supply current (IDDrms) determines the internal power
dissipation of the amplifier.
An easy-to-use equation to calculate efficiency starts out as being equal to the ratio of power from the power
supply to the power delivered to the load. To accurately calculate the RMS and average values of power in the
load and in the amplifier, the current and voltage waveform shapes must first be understood (see Figure 28).
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相關代理商/技術參數 |
參數描述 |
|---|---|
| TPA6021A4N | 制造商:Texas Instruments 功能描述:Audio Power Amplifier IC 制造商:Texas Instruments 功能描述:IC, AUDIO POWER AMP, CLASS AB, 2W, DIP20 |
| TPA6021A4NE4 | 功能描述:音頻放大器 Stereo Class-AB w/Ster Hdphn Drive RoHS:否 制造商:STMicroelectronics 產品: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: 安裝風格:SMD/SMT 封裝 / 箱體:TQFP-64 封裝:Reel |
| TPA6030A4 | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:3-W Stereo Audio Power Amplifier with Advanced DC Volume Control |
| TPA6030A4_07 | 制造商:TI 制造商全稱:Texas Instruments 功能描述:3-2 STEREO AUDIO POWER AMPLIFIER WITH ADVANCED DC VOLUME CONTROL |
| TPA6030A4EVM | 功能描述:音頻 IC 開發工具 TPA6030A4 Eval Mod RoHS:否 制造商:Texas Instruments 產品:Evaluation Kits 類型:Audio Amplifiers 工具用于評估:TAS5614L 工作電源電壓:12 V to 38 V |
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