- 您现在的位置：买卖IC网 > PDF目录98254 > TLV320AIC3111IRHBT (TEXAS INSTRUMENTS INC) AUDIO AMPLIFIER, PQCC32 PDF资料下载
参数资料
| 型号： | TLV320AIC3111IRHBT |
| 厂商： | TEXAS INSTRUMENTS INC |
| 元件分类： | 音频／视频放大 |
| 英文描述： | AUDIO AMPLIFIER, PQCC32 |
| 封装： | 5 X 5 MM, GREEN, PLASTIC, QFN-32 |
| 文件页数： | 77/156页 |
| 文件大小： | 1701K |
| 代理商： | TLV320AIC3111IRHBT |
第1页第2页第3页第4页第5页第6页第7页第8页第9页第10页第11页第12页第13页第14页第15页第16页第17页第18页第19页第20页第21页第22页第23页第24页第25页第26页第27页第28页第29页第30页第31页第32页第33页第34页第35页第36页第37页第38页第39页第40页第41页第42页第43页第44页第45页第46页第47页第48页第49页第50页第51页第52页第53页第54页第55页第56页第57页第58页第59页第60页第61页第62页第63页第64页第65页第66页第67页第68页第69页第70页第71页第72页第73页第74页第75页第76页当前第77页第78页第79页第80页第81页第82页第83页第84页第85页第86页第87页第88页第89页第90页第91页第92页第93页第94页第95页第96页第97页第98页第99页第100页第101页第102页第103页第104页第105页第106页第107页第108页第109页第110页第111页第112页第113页第114页第115页第116页第117页第118页第119页第120页第121页第122页第123页第124页第125页第126页第127页第128页第129页第130页第131页第132页第133页第134页第135页第136页第137页第138页第139页第140页第141页第142页第143页第144页第145页第146页第147页第148页第149页第150页第151页第152页第153页第154页第155页第156页
www.ti.com
SLAS644B – JULY 2009 – REVISED OCTOBER 2009
register 82, bit D7 and page 1 / register 47, bit D7. Disabling the MIC PGA sets the gain to 0 dB. Muting
the ADC causes the digital output to mute so that the output value remains fixed. When soft-stepping is
enabled, the CODEC_CLKIN signal must stay active until after the ADC power-down register is written, in
order to ensure that soft-stepping to mute has had time to complete. When the ADC POWER UP flag is
no longer set, the CODEC_CLKIN signal can be shut down.
5.5.2
Automatic Gain Control (AGC)
The TLV320AIC3111 includes automatic gain control (AGC) for the microphone inputs. AGC can be used
to maintain nominally constant output-signal amplitude when recording speech signals. This circuitry
automatically adjusts the MIC PGA gain as the input signal becomes overly loud or very weak, such as
when a person speaking into a microphone moves closer to or farther from the microphone. The AGC
algorithm has several programmable settings, including target gain, attack and decay time constants,
noise threshold, and maximum PGA applicable, that allow the algorithm to be fine-tuned for any particular
application. The algorithm uses the absolute average of the signal (which is the average of the absolute
value of the signal) as a measure of the nominal amplitude of the output signal. Because the gain can be
changed at the sample interval time, the AGC algorithm operates at the ADC_fS clock rate.
Target level represents the nominal output level at which the AGC attempts to hold the ADC output
signal. The TLV320AIC3111 allows programming of eight different target levels, which can be
programmed from –5.5 dB to –24 dB relative to a full-scale signal. Because the TLV320AIC3111 reacts to
the signal absolute average and not to peak levels, it is recommended that the target level be set with
enough margin to avoid clipping at the occurrence of loud sounds.
An AGC low-pass filter is used to help determine the average level of the input signal. This average level
is compared to the programmed detection levels in the AGC to provide the correct functionality. This
low-pass filter is in the form of a first-order IIR filter. Programming this filter is done by writing to page 4 /
register 2 through page 4 / register 7. Two 8-bit registers are used to form the 16-bit digital coefficient as
shown on the register map. In this way, a total of six registers are programmed to form the three IIR
coefficients.
Attack time determines how quickly the AGC circuitry reduces the PGA gain when the input signal is too
loud. Programming the attack time is done by writing to page 0 / register 89, bits D7–D0.
Decay time determines how quickly the PGA gain is increased when the input signal is too low.
Programming the decay time is done by writing to page 0 / register 90, bits D7–D0.
Noise threshold is a reference level. If the input speech average value falls below the noise threshold,
the AGC considers it as a silence and hence brings down the gain to 0 dB in steps of 0.5 dB every sample
period and sets the noise-threshold flag. The gain stays at 0 dB unless the input speech signal average
rises above the noise-threshold setting. This ensures that noise is not amplified in the absence of speech.
The noise-threshold level in the AGC algorithm is programmable from –30 dB to –90 dB for the
microphone input. When the AGC noise threshold is set to –70 dB, –80 db, or –90 dB, the microphone
input maximum PGA applicable setting must be greater than or equal to 11.5 dB, 21.5 dB, or 31.5 dB,
respectively. This operation includes debounce and hysteresis to prevent the AGC gain from cycling
between high gain and 0 dB when signals are near the noise threshold level. When the noise-threshold
flag is set, the status of the gain applied by the AGC and the saturation flag should be ignored.
Programming the noise debounce is done by writing to page 0 / register 91, bits D4–D0. Programming the
signal debounce is done by writing to page 0 / register 92, bits D3–D0.
Max PGA applicable allows the user to restrict the maximum gain applied by the AGC. This can be used
for limiting PGA gain in situations where environmental noise is greater than the programmed noise
threshold. Microphone input maximum PGA can be programmed from 0 dB to 59.5 dB in steps of 0.5 dB.
Programming the maximum PGA gain allowed by the AGC is done by writing to page 0 / register 88,
bits D6–D0.
See Table 5-15 for various AGC programming options. AGC can be used only if the microphone input is
routed to the ADC channel.
Copyright 2009, Texas Instruments Incorporated
APPLICATION INFORMATION
27
Product Folder Link(s): TLV320AIC3111
相关PDF资料 |
PDF描述 |
|---|---|
| TLV320AIC3111IRHBR | AUDIO AMPLIFIER, PQCC32 |
| TLV320AIC3120IRHBR | AUDIO AMPLIFIER, PQCC32 |
| TLV320AIC3120IRHBT | AUDIO AMPLIFIER, PQCC32 |
| TLV320AIC31IRHBRG4 | SPECIALTY CONSUMER CIRCUIT, PQCC32 |
| TLV320AIC31IRHBR | SPECIALTY CONSUMER CIRCUIT, PQCC32 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| TLV320AIC3120 | 制造商:TI 制造商全称:Texas Instruments 功能描述:Low-Power Mono Audio Codec With Embedded miniDSP and Mono Class-D Speaker Amplifier |
| TLV320AIC3120EVM-U | 功能描述:音频 IC 开发工具 TLV320AIC3120EVM-U Eval Mod RoHS:否 制造商:Texas Instruments 产品:Evaluation Kits 类型:Audio Amplifiers 工具用于评估:TAS5614L 工作电源电压:12 V to 38 V |
| TLV320AIC3120IRHBR | 功能描述:接口—CODEC Low-Pwr Audio CODEC RoHS:否 制造商:Texas Instruments 类型: 分辨率: 转换速率:48 kSPs 接口类型:I2C ADC 数量:2 DAC 数量:4 工作电源电压:1.8 V, 2.1 V, 2.3 V to 5.5 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:DSBGA-81 封装:Reel |
| TLV320AIC3120IRHBT | 功能描述:接口—CODEC Low-Pwr Audio CODEC RoHS:否 制造商:Texas Instruments 类型: 分辨率: 转换速率:48 kSPs 接口类型:I2C ADC 数量:2 DAC 数量:4 工作电源电压:1.8 V, 2.1 V, 2.3 V to 5.5 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:DSBGA-81 封装:Reel |
| TLV320AIC31EVM | 功能描述:音频 IC 开发工具 TLV320AIC31 Eval Mod RoHS:否 制造商:Texas Instruments 产品:Evaluation Kits 类型:Audio Amplifiers 工具用于评估:TAS5614L 工作电源电压:12 V to 38 V |
发布紧急采购，3分钟左右您将得到回复。