一种适用于生物电信号处理的全集成五阶Gm-C低通滤波器
|
摘要
传统的Gm-C滤波器OTA输入晶体管大多工作在饱和区,存在输入动态范围较小和跨导值较大等不足,难以满足生物医学电信号处理滤波器所要求的超低截止频率、低功耗与大输入动态范围等要求,采用将输入晶体管钳位到线性工作区的方法,设计了跨导线性可调的OTA以提高滤波器能够处理的信号幅度。并应用该OTA综合了一种五阶Gm-C超低频低通滤波器。仿真结果表明,该滤波器在1.8 V电源,800 m Vpp输入条件下实现了283 Hz的超低低通角频率,-6.4 d B的带内增益,51 d B的三次谐波失真,功耗仅为22μW,适用于可穿戴式生物医学电信号读取电路。
As the OTA input transistors of traditional Gm-C filter usually operate in the saturated zone and have the disadvantages of small input dynamic range and large transconductance value,it is difficult to meet the requirements of ultra-low cutoff frequency,low power consumption,and large input dynamic range required by biomedical electrical signal processing filter.Therefore,a linear and tunable transconductance OTA was designed with the method of clamping the input transistor to the linear operation zone to improve the signal amplitude that the filter can process. The OTA is utilized to synthesize a fifth-order Gm-C low-pass filter with ultra-low frequency. The simulation results show that the filter can achieve 283 Hz ultra-low-pass angle frequency,-6.4 d B in-band gain,and 51 d B third harmonic distortion under the input condition of 1.8 V power supply and 800 m Vpp.The power consumption of the filter is only 22 μW which is suitable for the wearable biomedical electrical signal readout circuit.
As the OTA input transistors of traditional Gm-C filter usually operate in the saturated zone and have the disadvantages of small input dynamic range and large transconductance value,it is difficult to meet the requirements of ultra-low cutoff frequency,low power consumption,and large input dynamic range required by biomedical electrical signal processing filter.Therefore,a linear and tunable transconductance OTA was designed with the method of clamping the input transistor to the linear operation zone to improve the signal amplitude that the filter can process. The OTA is utilized to synthesize a fifth-order Gm-C low-pass filter with ultra-low frequency. The simulation results show that the filter can achieve 283 Hz ultra-low-pass angle frequency,-6.4 d B in-band gain,and 51 d B third harmonic distortion under the input condition of 1.8 V power supply and 800 m Vpp.The power consumption of the filter is only 22 μW which is suitable for the wearable biomedical electrical signal readout circuit.
引文
[1]WILLAMS A B,TAYLOR F J.Electronic filter design handbook[M].New York:Mc Graw-Hill,2006.
[2]GALAN J,PEDRO M,SANCHEZ-RODRIGUEZ T,et al.A very linear low-pass filter with automatic frequency tuning[J].IEEE transactions on very large scale integration systems,2013,21(1):182-187.
[3]段吉海,郝强宇,徐卫林,等.一种适用于心电信号检测的斩波前置放大器[J].微电子学,2016(1):29-33.DUAN Jihai,HAO Qiangyu,XU Weilin,et al.A chopper stabilized preamplifier for ECG signal acquisition[J].Microelectronics,2016(1):29-33.
[4]SCHAUMANN R,XIAO H,VAN VALKENBURG M E.Design of analog filters[M].Oxford:Oxford University Press,2001.
[5]DE LIMA J A,DUALIBLE C.A linearly tunable low-voltage CMOS transconductor with improved common-mode stability and its application to Gm-C filters[J].IEEE transactions on circuits&systems II analog&digital signal processing,2001,48(7):649-660.
[6]DUAN Jihai,LAN Chuang,XU Weilin.An OTA-C filter for ECG acquisition systems with highly linear range and less passband attenuation[J].Journal of semiconductors,2015,36(5):120-125.
[7]SOLIS-BUSTOS S,SILVA-Martínez J,MALOBERTI F.A 60-d B dynamic-range CMOS sixth-order 2.4 Hz low-pass filter for medical application[J].IEEE transactions on circuits systems II analog&digital signal processing,2000,47(12):1391-1398.
[8]LASANEN K,KOSTAMOVAARA J.A 1-V analog CMOS frontend for detecting QRS complexes in a cardiac signal[J].IEEE transactions on circuits&systems I:regular papers,2005,52(12):2584-2594.
[9]LEE S Y,CHENG C J.Systematic design and modeling of a OTA-C filter for portable ECG detection[J].IEEE transactions on biomedical circuits&systems,2009,3(1):53-64.
[10]MAHMOUD S A,BAMAKHRAMAH A,AL-TUNAIJI S A.Low-noise low-pass filter for ECG portable detection systems with digitally programmable range[J].Circuits systems and signal processing,2013,32(5):2029-2045.
[11]周德福,张勇虎,葛锐,等.可变带宽OTA-C连续时间低通滤波器设计[J].现代电子技术,2011,34(6):157-159.ZHOU Defu,ZHANG Yonghu,GE Rui,et al.Design of variablebandwidth OTA-C continuous-time low-pass filter[J].Modern electronics technique,2011,34(6):157-159.
[2]GALAN J,PEDRO M,SANCHEZ-RODRIGUEZ T,et al.A very linear low-pass filter with automatic frequency tuning[J].IEEE transactions on very large scale integration systems,2013,21(1):182-187.
[3]段吉海,郝强宇,徐卫林,等.一种适用于心电信号检测的斩波前置放大器[J].微电子学,2016(1):29-33.DUAN Jihai,HAO Qiangyu,XU Weilin,et al.A chopper stabilized preamplifier for ECG signal acquisition[J].Microelectronics,2016(1):29-33.
[4]SCHAUMANN R,XIAO H,VAN VALKENBURG M E.Design of analog filters[M].Oxford:Oxford University Press,2001.
[5]DE LIMA J A,DUALIBLE C.A linearly tunable low-voltage CMOS transconductor with improved common-mode stability and its application to Gm-C filters[J].IEEE transactions on circuits&systems II analog&digital signal processing,2001,48(7):649-660.
[6]DUAN Jihai,LAN Chuang,XU Weilin.An OTA-C filter for ECG acquisition systems with highly linear range and less passband attenuation[J].Journal of semiconductors,2015,36(5):120-125.
[7]SOLIS-BUSTOS S,SILVA-Martínez J,MALOBERTI F.A 60-d B dynamic-range CMOS sixth-order 2.4 Hz low-pass filter for medical application[J].IEEE transactions on circuits systems II analog&digital signal processing,2000,47(12):1391-1398.
[8]LASANEN K,KOSTAMOVAARA J.A 1-V analog CMOS frontend for detecting QRS complexes in a cardiac signal[J].IEEE transactions on circuits&systems I:regular papers,2005,52(12):2584-2594.
[9]LEE S Y,CHENG C J.Systematic design and modeling of a OTA-C filter for portable ECG detection[J].IEEE transactions on biomedical circuits&systems,2009,3(1):53-64.
[10]MAHMOUD S A,BAMAKHRAMAH A,AL-TUNAIJI S A.Low-noise low-pass filter for ECG portable detection systems with digitally programmable range[J].Circuits systems and signal processing,2013,32(5):2029-2045.
[11]周德福,张勇虎,葛锐,等.可变带宽OTA-C连续时间低通滤波器设计[J].现代电子技术,2011,34(6):157-159.ZHOU Defu,ZHANG Yonghu,GE Rui,et al.Design of variablebandwidth OTA-C continuous-time low-pass filter[J].Modern electronics technique,2011,34(6):157-159.