参数资料
型号: TPA2031D1YZFR
厂商: TEXAS INSTRUMENTS INC
元件分类: 音频/视频放大
英文描述: 2.5 W, 2 CHANNEL, AUDIO AMPLIFIER, BGA9
封装: 1.45 X1.45 MM, LEAD FREE, WCSP-9
文件页数: 11/24页
文件大小: 754K
代理商: TPA2031D1YZFR
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
www.ti.com........................................................................................................................................................................................................ SLOS546 – MAY 2008
Figure 37. The TPA2031D1 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 TPA2031D1 modulation scheme has very little loss in the load without a filter because the pulses are very
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 very 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, ηTHEORETICAL.
Copyright 2008, Texas Instruments Incorporated
19
Product Folder Link(s): TPA2031D1
相关PDF资料
PDF描述
TPA2032D1YZFR 2.75 W, 1 CHANNEL, AUDIO AMPLIFIER, BGA9
TPA2032D1YZF 2.75 W, 1 CHANNEL, AUDIO AMPLIFIER, BGA9
TPA2034D1YZFR 2.75 W, 1 CHANNEL, AUDIO AMPLIFIER, BGA9
TPA2034D1YZF 2.75 W, 1 CHANNEL, AUDIO AMPLIFIER, BGA9
TPA2033D1YZFR 2.75 W, 1 CHANNEL, AUDIO AMPLIFIER, BGA9
相关代理商/技术参数
参数描述
TPA2031D1YZFT 功能描述:音频放大器 2.5W Mono Class-D Aud Pwr Amp 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
TPA2032D1 制造商:TI 制造商全称:Texas Instruments 功能描述:2.75-W FIXED GAIN MONO FILTER-FREE CLASS-D AUDIO POWER AMPLIFIER
TPA2032D1YZF 制造商:TI 制造商全称:Texas Instruments 功能描述:2.75-W FIXED GAIN MONO FILTER-FREE CLASS-D AUDIO POWER AMPLIFIER
TPA2032D1YZFR 功能描述:音频放大器 2.75W Mon Fully Diff Class-D Aud Amp 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
TPA2032D1YZFT 功能描述:音频放大器 2.75W Mon Fully Diff Class-D Aud Amp 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