一种增益可控音频前置放大器电路的设计  

Design of Variable-Gain Pre-Amplifier Circuit for Audio Power Amplifier

作　　者：潘文光[1] 于云丰[1] 马成炎[2] 叶甜春[1] 

机构地区：[1]中国科学院微电子研究所,北京100029 [2]杭州中科微电子有限公司,杭州310053

出　　处：《微电子学》2010年第2期186-189,共4页Microelectronics

基　　金：国家科技重大专项(2009ZX02304-003-1)

摘　　要：设计了一种基于0.5μm CMOS工艺的增益可控音频前置放大器电路。该电路采用直流音量控制方式控制前置放大器的增益,进而实现整体音频放大器的音量控制。外部输入的直流模拟电压经过片内模数转换器转换成数字控制信号,控制前置放大器的输入电阻与反馈电阻的比值,从而实现前置放大器的增益控制。该放大器能够实现32档的音量控制范围,增益从-50 dB变化到25 dB,电路版图面积为1.2 mm×0.8 mm。A variable-gain pre-amplifier circuit for audio power amplifier was implemented in 0. 5μm CMOS process. In this circuit, DC volume control operation mode was adopted to control gain of the pre-amplifier, and by adjusting the gain of the pre-amplifier, volume of the whole audio power amplifier could be controlled. The input DC analog voltage signal was converted to digital control signals with an on-chip A/D converter, which was used to adjust ratio of feedback resistance to input resistance, thus realizing gain control of the pre-amplifier. The amplifier could of- fer a 32-step DC volume control from -50 dB to 25 dB. The circuit occupies a layout area of 1.2 mm×0. 8 mm.

关 键 词：音频功率放大器 音量控制 前置放大器 

分 类 号：TN722.75[电子电信—电路与系统]