A current mode feed-forward gain control system for a 0.8 V CMOS hearing aid  

作　　者：李凡阳 杨海钢 刘飞 尹幍 

机构地区：[1]Institute of Electronics,Chinese Academy of Sciences [2]Graduate University of the Chinese Academy of Sciences

出　　处：《Journal of Semiconductors》2011年第6期126-131,共6页半导体学报（英文版）

基　　金：Project supported by the National High Technology Research and Development Program of China(No2008AA010701)

摘　　要：A current mode feed-forward gain control（CMFGC）technique is presented,which is applied in the front-end system of a hearing aid chip.Compared with conventional automatic gain control（AGC）,CMFGC significantly improves the total harmonic distortion（THD）by digital gain control.To attain the digital gain control codes according to the extremely weak output signal from the microphone,a rectifier and a state controller implemented in current mode are proposed.A prototype chip has been designed based on a 0.13μm standard CMOS process.The measurement results show that the supply voltage can be as low as 0.6 V.And with the 0.8 V supply voltage,the THD is improved and below 0.06%（-64 dB）at the output level of 500 mV_（p-p）,yet the power consumption is limited to 40μW.In addition,the input referred noise is only 4μV_（rms）and the maximum gain is maintained at 33 dB.A current mode feed-forward gain control（CMFGC）technique is presented,which is applied in the front-end system of a hearing aid chip.Compared with conventional automatic gain control（AGC）,CMFGC significantly improves the total harmonic distortion（THD）by digital gain control.To attain the digital gain control codes according to the extremely weak output signal from the microphone,a rectifier and a state controller implemented in current mode are proposed.A prototype chip has been designed based on a 0.13μm standard CMOS process.The measurement results show that the supply voltage can be as low as 0.6 V.And with the 0.8 V supply voltage,the THD is improved and below 0.06%（-64 dB）at the output level of 500 mV_（p-p）,yet the power consumption is limited to 40μW.In addition,the input referred noise is only 4μV_（rms）and the maximum gain is maintained at 33 dB.

关 键 词：current mode gain control hearing aid 

分 类 号：TH785.1[机械工程—仪器科学与技术]