电容式微机械加速度传感器检测电路研究
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摘要
加速度传感器是一种重要的惯性传感器,它被广泛地运用在惯性导航、消费电子、汽车电子和地质勘探等各个领域。硅微机械加速度计作为一种可以测量加速度的传感器,可分为压电式、隧道式、压阻式和电容式等。
其中电容式微机械加速度传感器具有分辨率高、动态范围大、温度特性好等优点,从而得到了广泛的应用。电容式微机械加速度系统由加速度敏感元件和电容检测电路组成,因此电容检测电路的性能直接影响了电容式微机械加速度系统的整体性能,提高电容检测电路的性能是电容式微机械加速度系统设计中一个十分重要的部分。
本文针对变面积电容式微机械加速度计,设计了单路载波调制型检测电路,并对其工作原理进行了分析,对电路的温度特性进行了分析和测量,最后对MEMS三轴加速度计的检测电路进行了小型化和工程化工作。
本论文主要工作如下:
(1)设计了单路载波调制型电容检测电路,包括载波发生模块,带通滤波模块,电荷放大模块,仪表放大模块,移相模块,同步解调模块,低通滤波模块,分析了各个模块的工作原理和限制因素。
(2)针对单载波调制型检测电路,分析了各个模块的参数变化和PCB板的寄生效应等因素对检测电路的影响对系统的影响;同时重点分析了温度变化对系统的影响;针对实验室以前的单轴加速度计的检测电路受温度的影响而容易发生漂移的缺点,从降低系统功耗和改善系统热设计两个方面入手,设计了三轴加速度计的检测电路。
(3)参考加速度计相关测试标准,制定了加速度计性能测试方案,建立了测试平台。根据该方案,对加速度计系统性能进行了全面的测试。
测量结果表明:加速度计的标度因数为115.43mV/g,一小时之内的零偏稳定性为2.254*10~(-4)g,启动时间约为1500s,阈值约为0.12mg,分辨率约为0.1mg,-1g～+1g的线性度为99.999%,带宽约为140Hz。
Accelerometer is a kind of important inertial sensor that can be used in inertial navigation, consumer electronics, motor electronics and geologic exploration. Silicon micro-accelerometer can measure the acceleration of the movement, and there are many kinds of Micro-accelerometer based on piezoelectric, tunnel, piezoresistive, capacitive effect.
Capacitive MEMS micro-accelerometer is widely used because of its high resolution, large dynamic range and low temperature drift. Capacitive MEMS accelerometer consists of acceleration sensor and capacitance detection circuit. The performance of capacitance detection circuit has a direct impact on the performance of accelerometer system. The improvement of capacitance detection circuit performance is important in determining the performance of accelerometers.
A single carrier modulation capacitance detection circuit is designed for an area changing type capacitive MEMS accelerometer. The principle of this circuit is analysed, and temperature characteristics of this circuit is analysed and measured, at last miniaturization and engineering of triaxial MEMS accelerometer was finished.
The major work of this thesis contains:
(1) A single carrier modulation capacitance detection circuit consisting of DDS module, BFP module, charge amplifier module, instrument amplifier module, active phaser module, synchronously demodulation module and LPF module was designed, while operation principle and constraining factor of every module was anlysed, and parameter of every module was figured out according to theory.
(2) According to single carrier modulation detection circuit, the parameter of every module and the influence of PCB board parasitic effect was figured out. The impact of temperature on accelerometer system was also analysed minutely. Duing to temperature drift of previous accelerometer system, a new triaxial MEMS accelerometer system was design which has lower power consumption and better heat emanation design.
(3) A performance test scheme was made with reference to test guides on accelerometers. The measurement shows that capacitive MEMS accelerometer has asensitivity of 115.43mV/g, zero-draft of 2.246*10~(-4)g. Start-Up time of 1500s,threshold value of 0.12mg , resolution of 0.1 mg, linearity of 99.999% and bandwidthof 140Hz.
其中电容式微机械加速度传感器具有分辨率高、动态范围大、温度特性好等优点,从而得到了广泛的应用。电容式微机械加速度系统由加速度敏感元件和电容检测电路组成,因此电容检测电路的性能直接影响了电容式微机械加速度系统的整体性能,提高电容检测电路的性能是电容式微机械加速度系统设计中一个十分重要的部分。
本文针对变面积电容式微机械加速度计,设计了单路载波调制型检测电路,并对其工作原理进行了分析,对电路的温度特性进行了分析和测量,最后对MEMS三轴加速度计的检测电路进行了小型化和工程化工作。
本论文主要工作如下:
(1)设计了单路载波调制型电容检测电路,包括载波发生模块,带通滤波模块,电荷放大模块,仪表放大模块,移相模块,同步解调模块,低通滤波模块,分析了各个模块的工作原理和限制因素。
(2)针对单载波调制型检测电路,分析了各个模块的参数变化和PCB板的寄生效应等因素对检测电路的影响对系统的影响;同时重点分析了温度变化对系统的影响;针对实验室以前的单轴加速度计的检测电路受温度的影响而容易发生漂移的缺点,从降低系统功耗和改善系统热设计两个方面入手,设计了三轴加速度计的检测电路。
(3)参考加速度计相关测试标准,制定了加速度计性能测试方案,建立了测试平台。根据该方案,对加速度计系统性能进行了全面的测试。
测量结果表明:加速度计的标度因数为115.43mV/g,一小时之内的零偏稳定性为2.254*10~(-4)g,启动时间约为1500s,阈值约为0.12mg,分辨率约为0.1mg,-1g～+1g的线性度为99.999%,带宽约为140Hz。
Accelerometer is a kind of important inertial sensor that can be used in inertial navigation, consumer electronics, motor electronics and geologic exploration. Silicon micro-accelerometer can measure the acceleration of the movement, and there are many kinds of Micro-accelerometer based on piezoelectric, tunnel, piezoresistive, capacitive effect.
Capacitive MEMS micro-accelerometer is widely used because of its high resolution, large dynamic range and low temperature drift. Capacitive MEMS accelerometer consists of acceleration sensor and capacitance detection circuit. The performance of capacitance detection circuit has a direct impact on the performance of accelerometer system. The improvement of capacitance detection circuit performance is important in determining the performance of accelerometers.
A single carrier modulation capacitance detection circuit is designed for an area changing type capacitive MEMS accelerometer. The principle of this circuit is analysed, and temperature characteristics of this circuit is analysed and measured, at last miniaturization and engineering of triaxial MEMS accelerometer was finished.
The major work of this thesis contains:
(1) A single carrier modulation capacitance detection circuit consisting of DDS module, BFP module, charge amplifier module, instrument amplifier module, active phaser module, synchronously demodulation module and LPF module was designed, while operation principle and constraining factor of every module was anlysed, and parameter of every module was figured out according to theory.
(2) According to single carrier modulation detection circuit, the parameter of every module and the influence of PCB board parasitic effect was figured out. The impact of temperature on accelerometer system was also analysed minutely. Duing to temperature drift of previous accelerometer system, a new triaxial MEMS accelerometer system was design which has lower power consumption and better heat emanation design.
(3) A performance test scheme was made with reference to test guides on accelerometers. The measurement shows that capacitive MEMS accelerometer has asensitivity of 115.43mV/g, zero-draft of 2.246*10~(-4)g. Start-Up time of 1500s,threshold value of 0.12mg , resolution of 0.1 mg, linearity of 99.999% and bandwidthof 140Hz.
引文
[1]王正通,张斌珍.基于微机械加速度计的无键多功能电视遥控器.电子设计工程.2009年9月.第17卷第9期,pp.23-24.
[2]徐叶雷,方勇.基于MEMS加速度计的车用自动呼救系统.传感技术学报.2009年6月.第22卷第6期,pp.887-892.
[3]Mark lemkin,Member,IEEE,and Berhard E.Boser,Member,IEEE."A Three-Axis Micromachined Accelerometer with a CMOS Position-Sense Interface and Digital Offset-Trim Electronics".IEEE JOURNAL OF SOLID-STATE CIRCUITS,VOL.34,NO.4,APRIL 1999,pp.456-468.
[4]J.H.Smith,S.Montague,J.J.Sniegowski,J.R.Murray,and P.J.McWhorter,"Embedded micromechanical devices for the monolithic integration of MEMS with CMOS"Proc.IEDM,Dec.1995,pp.609-612.
[5]W.Henrion,L.Disanza,M.Ip,S.Terry,and H.Jerman,"Wide dynamic ranger direct digital acceleromter",Pro.IEEE Solid-State Sensor and Actuator Workshop,Hilton Head Island,SC,June 1990,pp.153-157.
[6]刘晓为,王超,谭晓昀,董长春.体硅电容式双轴微加速度计的信号检测新方法 传感技术学报.2008年3月,第21卷第3期,pp.490-493.
[7]Bernhard E.Boser and Roger T.Howe,Fellow,IEEE,"Surface Micromachined Accelerometers",IEEE JOURNAL OF SOLID-STATE CIRCUITS,VOL.31,NO.3,MARCH 1996,pp.366-375.
[8]M.Lemkin,M.Ortiz,N.Wongkomet,B.E.Boser and J.H.Smith,"A 3-axis surface micromachined sigma-delta accelerometer" ISSCC Dig.Tech.papers,Feb.1997,pp.202-203.
[9]G.Zhang,H.Xie,L.E.de Rosset,and G.K.Fedder,"A lateral capacitive CMOS accelerometer with structural curl compesation",12th IEEE Int.Conf.Micro Electro Mechanical System,Orlando,FL,1999,pp.606-611.
[10]J.Wu,G.K.Fedder and L.R.Carley,"A low-noise low-offset capacitive sensing amplifier for a 50-μg/Hz~(1/2) monolitihic CMOS MEMS accelerometer",IEEE Journal of Solid-State Circuits,39(5),2004,pp.722-730.
[11]Huang SH S,LI X X and Wang Y L,"A piezoresistive accelerometer wit haxially stressed tiny beams for both much increased sensitivity and much broadened frequency bandwidth",The 12th International Confernce on Solid State Sensors,Act.Proc.Transducers,2003,pp.91-94.
[12]Andrew R A,Robert SO and Kevin T K,"Simulation,Fabrication and Testing of Bulk Micromachined SIC HIGH g Piezoresitive Accelerometer",Sensors and Actuators,2003,104,pp.11-18.
[13]A.Garcia-Valenzuela and M.Tabib-Azar,"Comparative study of piezoelectric,piezoresistive,electrostatic,magnetic and optical sensors",Proc.SPIE,July 1994,Vol.2291,pp.125-142.
[14]Li G,Li Z and Wang C,"Design and simulation of a novel highly symmetrical piezoelectric triaxial accelerometer",San Diego CA:Proc of the Modeling and Simulation of Microsystems Confernce,2000.
[15]Scheeper P R,Reynold J K and Kenny T W,"Development of a modal analysis accelerometer based on a tunneling displacement transducer",International Conference on Solid State Sensors and Actuators,Chicago,1997,pp.867-871.
[16]Yeh C and Najafi K,"A low-voltage tunneling-based silicon microaccelerometer",IEEE Transactions on Electron Devices,1997,pp.1875-1882.
[17]钟莹,张国雄,李醒飞,“新型谐振式硅微机械加速度计”,纳米技术与精密工程,2003年12月,第1卷第1期,pp.34-37.
[18]刘俊,石云波,李杰,微惯性技术,第一版,电子工业出版社,2005,pp.127-131.
[19]Y.E.Park and K.D.Wise,"An MOS Switched-Capacitor Readout Amplifier for Capacitive Pressure Sensors",IEEE Custom IC Conf,1983,pp.380-384.
[20]K.Watanabe and G.C.Temes,"A switch-capacitor digital capacitance bridge",IEEE Trans.Instrum.Meas.,vol.33 Dec.1984,pp247-251.
[21]Michael Suster,Jun Guo,Nattapon Chaimanonart,Wen H.Ko,and Darrin J.Young.Low-Noise CMOS Integrated Sensing Electronics for Capacitive MEMS Strain Sensors.
[22]李希文,赵健,白小平传感器与信号调理技术,第一版,西安电子科技大学出版社,2008,pp.261-263.
[23]Harrison D.and Dimeff J,"A diode-quad bridge circuit for use with capacitance transducers",Rev.Sci.Instrum.,Vol.44,No.10,Oct.1973,pp.1648-1472.
[24]Henrik Rodjegard and Anders Loof,"A differential charge-transfer readout circuit for multiple output capacitive sensors",Sensors and Actuators,2005,119,pp.309-315.
[25]Mark A.Lemkin,Bernhard E.Boser,David Auslander and Jim H.Smith,"A 3-Axis Force Balanced Accelerometer Using a Single Proof-Mass",International Conference on Solid State Sensors and Actuators,Chicago,1997,pp.1185-1188.
[26]Dong Ki Min and Jong Up Jeon,"Parameter Design of the Capacitive Position Sensing Circuit for a Differential-driven Electrostatic Microactuator",Sensors for Industry Conference Rosemount Illinois,Nov.2001,pp.168-171.
[27]Jiangfeng Wu,Gary K.Fedder,and L.Richard Carley,Fellow,IEEE.A Low-Noise Low-Offset Capacitive Sensing Amplifier for a Monolithic CMOS MEMS Accelerometer.IEEE JOURNAL OF SOLID-STATE CIRCUITS,VOL.39,NO.5,MAY 2004.
[28]J.C.Lotters et al,"A sensitive differential capacitance to voltage converter for sensor application",IEEE Trans.on Instrum.And Meas.,vol.48,no.l,1999,pp.89-96.
[29]Ebrahim Ghafar-Zadeh and Mohamad Sawan,A High Precision and Linearity Differential Capacitive Sensor Circuit Dedicated to Bioparticles Detection,The 3rd International IEEE-NEWCAS Conference,19-22,June,2005,299-302
[30]丁超,张科峰,王磊,“一种新型高精度数字RC振荡电路”,计算机与数字工程,第35卷第11期,2007,pp.167-169.
[31]Alexander A V,Sergey V A and Yakov L V,"New concept and practical results for new very low profile precision OCXOs",IEEE International Frequency Control Symposium and PDA,2001,00.423-429.
[32]汉泽西,张海飞,王文勃,李国栋,“基于DDS技术正弦波信号发生器的设 计”,电子测试,第8期,2009年8月,pp.65-77.
[33]任鹏,周资伟,朱江,“一种基于DDS和PLL技术本振源的设计与实现”,现在电子技术,第9期,2009年,PP.178-180.
[34]Nicholas H T,H.Samuleia and Kim B,"The optimization of Direct Digit a Frequency Synthesizer Performance in the Presence of Finite Word Length effects",IEEE Proc 42th AFCS,1988,pp.357-363
[35]张亚,黄克平,“有源模拟带通滤波器的设计”,电子科技,第22卷,第1期,2009,pp.9-12.
[36]S.Franco,“基于运算放大器和模拟集成电路的电路设计”,第三版,西安交通大学出版社,2004,pp.121-124.
[37]林凌,王小林,李刚,王朔,刘铭,“一种新型锁相放大器检测电路”,天津大学学报,第38卷,第1期,2005年,pp.65-68.
[38]Johansson HO,"A simple precharged CMOS phase/frequency detector",IEEE J Sol Sta Cir,1998,33(2),pp.295-299.
[39]Agarwal A.,Sampath H.,Yelamanchili V.and Vemuri R.,"Accurate estimation of parasitic capacitances in analog circuits Design",Automation and Test in Europe Conference and Exhibition,Volume 2,2004,pp.1364 -1365.
[40]Yamanaga K.,Sato T.and Masu K.,"Accurate parasitic inductance determination of a ceramic capacitor through 2-port measurements",Electrical Performance of Electronic Packaging,IEEE,Oct.2008,pp.119-122.
[2]徐叶雷,方勇.基于MEMS加速度计的车用自动呼救系统.传感技术学报.2009年6月.第22卷第6期,pp.887-892.
[3]Mark lemkin,Member,IEEE,and Berhard E.Boser,Member,IEEE."A Three-Axis Micromachined Accelerometer with a CMOS Position-Sense Interface and Digital Offset-Trim Electronics".IEEE JOURNAL OF SOLID-STATE CIRCUITS,VOL.34,NO.4,APRIL 1999,pp.456-468.
[4]J.H.Smith,S.Montague,J.J.Sniegowski,J.R.Murray,and P.J.McWhorter,"Embedded micromechanical devices for the monolithic integration of MEMS with CMOS"Proc.IEDM,Dec.1995,pp.609-612.
[5]W.Henrion,L.Disanza,M.Ip,S.Terry,and H.Jerman,"Wide dynamic ranger direct digital acceleromter",Pro.IEEE Solid-State Sensor and Actuator Workshop,Hilton Head Island,SC,June 1990,pp.153-157.
[6]刘晓为,王超,谭晓昀,董长春.体硅电容式双轴微加速度计的信号检测新方法 传感技术学报.2008年3月,第21卷第3期,pp.490-493.
[7]Bernhard E.Boser and Roger T.Howe,Fellow,IEEE,"Surface Micromachined Accelerometers",IEEE JOURNAL OF SOLID-STATE CIRCUITS,VOL.31,NO.3,MARCH 1996,pp.366-375.
[8]M.Lemkin,M.Ortiz,N.Wongkomet,B.E.Boser and J.H.Smith,"A 3-axis surface micromachined sigma-delta accelerometer" ISSCC Dig.Tech.papers,Feb.1997,pp.202-203.
[9]G.Zhang,H.Xie,L.E.de Rosset,and G.K.Fedder,"A lateral capacitive CMOS accelerometer with structural curl compesation",12th IEEE Int.Conf.Micro Electro Mechanical System,Orlando,FL,1999,pp.606-611.
[10]J.Wu,G.K.Fedder and L.R.Carley,"A low-noise low-offset capacitive sensing amplifier for a 50-μg/Hz~(1/2) monolitihic CMOS MEMS accelerometer",IEEE Journal of Solid-State Circuits,39(5),2004,pp.722-730.
[11]Huang SH S,LI X X and Wang Y L,"A piezoresistive accelerometer wit haxially stressed tiny beams for both much increased sensitivity and much broadened frequency bandwidth",The 12th International Confernce on Solid State Sensors,Act.Proc.Transducers,2003,pp.91-94.
[12]Andrew R A,Robert SO and Kevin T K,"Simulation,Fabrication and Testing of Bulk Micromachined SIC HIGH g Piezoresitive Accelerometer",Sensors and Actuators,2003,104,pp.11-18.
[13]A.Garcia-Valenzuela and M.Tabib-Azar,"Comparative study of piezoelectric,piezoresistive,electrostatic,magnetic and optical sensors",Proc.SPIE,July 1994,Vol.2291,pp.125-142.
[14]Li G,Li Z and Wang C,"Design and simulation of a novel highly symmetrical piezoelectric triaxial accelerometer",San Diego CA:Proc of the Modeling and Simulation of Microsystems Confernce,2000.
[15]Scheeper P R,Reynold J K and Kenny T W,"Development of a modal analysis accelerometer based on a tunneling displacement transducer",International Conference on Solid State Sensors and Actuators,Chicago,1997,pp.867-871.
[16]Yeh C and Najafi K,"A low-voltage tunneling-based silicon microaccelerometer",IEEE Transactions on Electron Devices,1997,pp.1875-1882.
[17]钟莹,张国雄,李醒飞,“新型谐振式硅微机械加速度计”,纳米技术与精密工程,2003年12月,第1卷第1期,pp.34-37.
[18]刘俊,石云波,李杰,微惯性技术,第一版,电子工业出版社,2005,pp.127-131.
[19]Y.E.Park and K.D.Wise,"An MOS Switched-Capacitor Readout Amplifier for Capacitive Pressure Sensors",IEEE Custom IC Conf,1983,pp.380-384.
[20]K.Watanabe and G.C.Temes,"A switch-capacitor digital capacitance bridge",IEEE Trans.Instrum.Meas.,vol.33 Dec.1984,pp247-251.
[21]Michael Suster,Jun Guo,Nattapon Chaimanonart,Wen H.Ko,and Darrin J.Young.Low-Noise CMOS Integrated Sensing Electronics for Capacitive MEMS Strain Sensors.
[22]李希文,赵健,白小平传感器与信号调理技术,第一版,西安电子科技大学出版社,2008,pp.261-263.
[23]Harrison D.and Dimeff J,"A diode-quad bridge circuit for use with capacitance transducers",Rev.Sci.Instrum.,Vol.44,No.10,Oct.1973,pp.1648-1472.
[24]Henrik Rodjegard and Anders Loof,"A differential charge-transfer readout circuit for multiple output capacitive sensors",Sensors and Actuators,2005,119,pp.309-315.
[25]Mark A.Lemkin,Bernhard E.Boser,David Auslander and Jim H.Smith,"A 3-Axis Force Balanced Accelerometer Using a Single Proof-Mass",International Conference on Solid State Sensors and Actuators,Chicago,1997,pp.1185-1188.
[26]Dong Ki Min and Jong Up Jeon,"Parameter Design of the Capacitive Position Sensing Circuit for a Differential-driven Electrostatic Microactuator",Sensors for Industry Conference Rosemount Illinois,Nov.2001,pp.168-171.
[27]Jiangfeng Wu,Gary K.Fedder,and L.Richard Carley,Fellow,IEEE.A Low-Noise Low-Offset Capacitive Sensing Amplifier for a Monolithic CMOS MEMS Accelerometer.IEEE JOURNAL OF SOLID-STATE CIRCUITS,VOL.39,NO.5,MAY 2004.
[28]J.C.Lotters et al,"A sensitive differential capacitance to voltage converter for sensor application",IEEE Trans.on Instrum.And Meas.,vol.48,no.l,1999,pp.89-96.
[29]Ebrahim Ghafar-Zadeh and Mohamad Sawan,A High Precision and Linearity Differential Capacitive Sensor Circuit Dedicated to Bioparticles Detection,The 3rd International IEEE-NEWCAS Conference,19-22,June,2005,299-302
[30]丁超,张科峰,王磊,“一种新型高精度数字RC振荡电路”,计算机与数字工程,第35卷第11期,2007,pp.167-169.
[31]Alexander A V,Sergey V A and Yakov L V,"New concept and practical results for new very low profile precision OCXOs",IEEE International Frequency Control Symposium and PDA,2001,00.423-429.
[32]汉泽西,张海飞,王文勃,李国栋,“基于DDS技术正弦波信号发生器的设 计”,电子测试,第8期,2009年8月,pp.65-77.
[33]任鹏,周资伟,朱江,“一种基于DDS和PLL技术本振源的设计与实现”,现在电子技术,第9期,2009年,PP.178-180.
[34]Nicholas H T,H.Samuleia and Kim B,"The optimization of Direct Digit a Frequency Synthesizer Performance in the Presence of Finite Word Length effects",IEEE Proc 42th AFCS,1988,pp.357-363
[35]张亚,黄克平,“有源模拟带通滤波器的设计”,电子科技,第22卷,第1期,2009,pp.9-12.
[36]S.Franco,“基于运算放大器和模拟集成电路的电路设计”,第三版,西安交通大学出版社,2004,pp.121-124.
[37]林凌,王小林,李刚,王朔,刘铭,“一种新型锁相放大器检测电路”,天津大学学报,第38卷,第1期,2005年,pp.65-68.
[38]Johansson HO,"A simple precharged CMOS phase/frequency detector",IEEE J Sol Sta Cir,1998,33(2),pp.295-299.
[39]Agarwal A.,Sampath H.,Yelamanchili V.and Vemuri R.,"Accurate estimation of parasitic capacitances in analog circuits Design",Automation and Test in Europe Conference and Exhibition,Volume 2,2004,pp.1364 -1365.
[40]Yamanaga K.,Sato T.and Masu K.,"Accurate parasitic inductance determination of a ceramic capacitor through 2-port measurements",Electrical Performance of Electronic Packaging,IEEE,Oct.2008,pp.119-122.