一种精确恒定跨导偏置的Gm-C滤波器设计  

Design of Gm-C filter with an accurate constant-Gm bias circuit

作　　者：郭桂良[1] 牟荣增[1] 杜占坤[1] 阎跃鹏[1] 

机构地区：[1]中国科学院微电子研究所,北京100029

出　　处：《江苏大学学报（自然科学版）》2011年第1期70-74,共5页Journal of Jiangsu University：Natural Science Edition

基　　金：国家"863"计划项目(2007AA01Z2a8)

摘　　要：针对片上Gm-C滤波器的自动频率调谐电路结构复杂、功耗大和精度低的问题,提出了一种精确的恒定跨导偏置电路.该电路通过使跨导管的跨导恒等于片外高精度电阻来稳定滤波器截止频率.给出了电路的推导,设计了滤波器及跨导器.将此电路应用于无线传感器网络节点芯片中九阶低通滤波器,进行了仿真;基于SMIC中0.18μm、1.8 V的1P6M CMOS工艺,采用无源LC滤波器原型综合的方法实现滤波器,并完成测试.结果表明,该滤波器的截止频率与设计值相差仅为1%,带内纹波小于0.8 dB,输入噪声电压小于25 nV/Hz～(1/2),功耗仅为1.6 mW,满足无线传感器网络节点芯片的要求.To improve the complex structure,high power consumption and low precision of on-chip Gm-C filter automatic frequency tuning circuits,an accurate constant-transconductance bias circuit was proposed.The cutoff frequency of the filter was stabilized by making the transconductance of the transconductance transistor identically equal to an off-chip high precision resistor.The operation theory was derived,and the filter and transconductor were designed.The circuit was applied to the 9th order low pass filter for wireless sensor chips,and the simulation was conducted.This chip was implemented in SMIC 0.18 μm 1.8 V 1P6M CMOS technology and the low pass filter was realized by the synthesis of passive LC filter prototype.The test results show that there is only a difference of 1% between the cutoff frequency and the designed value and the in-band ripple is less than 0.8 dB.The input-referred noise is less than 25 nV/Hz～（1/2） with a power consumption of 1.6 mW.The results meet the requirements of wireless sensor chips.

关 键 词：跨导电容滤波器 无线传感网 锁相环 恒定跨导 自动频率调谐 

分 类 号：TN742[电子电信—电路与系统]