基于连续时间反馈原理的闭环加速度计ASIC设计
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摘要
微机械加速度计作为一种重要的惯性传感器,在惯性制导、汽车、消费电子等各领域都有广泛的应用前景。本文在对电容式闭环微机械加速度计的机械结构、信号检测原理及闭环工作原理详细分析的基础上,利用0.5μm CMOS工艺库完成了基于连续时间反馈的闭环加速度计系统ASIC设计。
基于连续时间反馈原理的闭环加速度计接口电路主要由3部分构成:信号检测与处理电路、反馈控制电路和波形产生电路。其中信号检测与处理电路主要包括电荷敏感放大器、高通滤波器、斩波解调电路、低通滤波器和仪表放大器,这部分电路能够完成输入加速度信号的检测、放大与输出等功能。系统的反馈控制由PID控制器来完成,PID控制能够调整反馈信号的幅度和相位,提高系统的稳定性并改善系统的动态特性。波形产生电路主要用于产生高频正弦载波和解调用时钟信号,并对时钟信号进行延时处理以保证其在解调时与输入信号保持相位一致。
利用理想动力学方程和加速度计结构参数建立了加速度计机械结构的等效电学模型,并将该电学模型与接口电路构成闭环传感器系统进行HSPICE仿真。由仿真结果可知:闭环系统的满量程范围为±2g,检测灵敏度为0.94V/g,最小可检测加速度值为10μg。
在具体电路设计的基础上,本文对闭环传感器系统建立了等效噪声模型,并对系统中主要的噪声源进行了详细的分析,得到了一些优化闭环系统噪声特性的重要结论。
As an important inertial sensor, micro-accelerometer has broad application in field such as inertial guidance, automotive and consumer electronics. In this dissertation, we analyzed the mechanical structure of capacitive closed-loop micro-accelerometer, the principle of signal detection and closed-loop operation. Schematic of the ASIC based on continuous-time feedback for closed-loop micro-accelerometer has been designed with 0.5μm CMOS technology.
The interface circuit based on continuous-time feedback for closed-loop micro-accelerometer is composed of three parts: signal detection and operation circuit, feedback control circuit and waveform generation circuit. The signal detection and operation circuit consists of charge-sensitive amplifier, high-pass filter, chopped wave demodulator, low-pass filter and instrument amplifier, and it can detect, amply and output the acceleration. PID controller can control the amplitude and phase of the feedback signal to performance system feed-back control, that conduce to improve stability and dynamic characteristic of the system. Waveform generation circuit is used to generate the high-frequency carrier and the clock used for demodulation, it also can delay the clock to set the delay between the signal and the clock to zero.
Based on the ideal dynamics equation and the accelerometer structure parameters, the equivalent electrical model of the closed-loop accelerometer was established. The whole system composed of the equivalent electrical model and interface circuit was simulated with HSPICE. The circuit performance as follow: the full measurement range can be achieved±2g, the sensitivity of the system is 0.94V/g, minimum detectable acceleration is 10μg.
Based on the design of the real circuit, we established equivalent noise model for the whole system. The analysis on important noise sources was presented, and arrived at some conclusions to optimize the noise characteristic of the whole system.
基于连续时间反馈原理的闭环加速度计接口电路主要由3部分构成:信号检测与处理电路、反馈控制电路和波形产生电路。其中信号检测与处理电路主要包括电荷敏感放大器、高通滤波器、斩波解调电路、低通滤波器和仪表放大器,这部分电路能够完成输入加速度信号的检测、放大与输出等功能。系统的反馈控制由PID控制器来完成,PID控制能够调整反馈信号的幅度和相位,提高系统的稳定性并改善系统的动态特性。波形产生电路主要用于产生高频正弦载波和解调用时钟信号,并对时钟信号进行延时处理以保证其在解调时与输入信号保持相位一致。
利用理想动力学方程和加速度计结构参数建立了加速度计机械结构的等效电学模型,并将该电学模型与接口电路构成闭环传感器系统进行HSPICE仿真。由仿真结果可知:闭环系统的满量程范围为±2g,检测灵敏度为0.94V/g,最小可检测加速度值为10μg。
在具体电路设计的基础上,本文对闭环传感器系统建立了等效噪声模型,并对系统中主要的噪声源进行了详细的分析,得到了一些优化闭环系统噪声特性的重要结论。
As an important inertial sensor, micro-accelerometer has broad application in field such as inertial guidance, automotive and consumer electronics. In this dissertation, we analyzed the mechanical structure of capacitive closed-loop micro-accelerometer, the principle of signal detection and closed-loop operation. Schematic of the ASIC based on continuous-time feedback for closed-loop micro-accelerometer has been designed with 0.5μm CMOS technology.
The interface circuit based on continuous-time feedback for closed-loop micro-accelerometer is composed of three parts: signal detection and operation circuit, feedback control circuit and waveform generation circuit. The signal detection and operation circuit consists of charge-sensitive amplifier, high-pass filter, chopped wave demodulator, low-pass filter and instrument amplifier, and it can detect, amply and output the acceleration. PID controller can control the amplitude and phase of the feedback signal to performance system feed-back control, that conduce to improve stability and dynamic characteristic of the system. Waveform generation circuit is used to generate the high-frequency carrier and the clock used for demodulation, it also can delay the clock to set the delay between the signal and the clock to zero.
Based on the ideal dynamics equation and the accelerometer structure parameters, the equivalent electrical model of the closed-loop accelerometer was established. The whole system composed of the equivalent electrical model and interface circuit was simulated with HSPICE. The circuit performance as follow: the full measurement range can be achieved±2g, the sensitivity of the system is 0.94V/g, minimum detectable acceleration is 10μg.
Based on the design of the real circuit, we established equivalent noise model for the whole system. The analysis on important noise sources was presented, and arrived at some conclusions to optimize the noise characteristic of the whole system.
引文
1张帅,贾育秦. MEMS技术的研究现状和新进展.现代制造工程. 2005, (9): 109～112
2金铃. MEMS技术研究及应用.现代雷达. 2004, 26(l2): 26～29
3李学东,余志伟.基于MEMS技术的微型传感器.仪表技术与传感器. 2005, 9: 4～7
4林俊.微电机系统(MEMS)的测试问题.国外电子测量技术. 2005, 8: 3～3
5 K. H. L. Chau, S. R. Lewis, Y. Zhao, et al.. An Integrated Force-balanced Capacitive Accelerometer for Low-G Applications. Sensors and Actuators A. 1996, 472~476
6 M. Tanaka. An Industrial and Applied Review of New MEMS Devices Features. Microelectronic Engineering. 2007, 84: 1341~1344
7 N. Barbour, J. Gilmore, et al.. Micromechanical Silicon Instrument and Systems Development at Draper Laboratory. AIAA Guidance, Navigation and Technology Conference, San Diego, 1996: 29~31
8 N. Yazdi, F. Ayazi, K. Najafi. Micromachined Inertial Sensors. Proceedings of the IEEE. 1998, 86(8): 1640~1659
9华冠雄译.惯性传感器技术的发展趋势.自动驾驶仪与红外技术. 2002, (2): 36~45
10 Applied MEMS Inc. An Extremely Low-Noise Micromachined Accelerometer with Custom ASIC circuitry. Sensors. 2001, 18(5): 52~56
11 Don L, DeVoe. Surface Micromachined Piezoelectric Accelerometers. Journal of Micoelectromechanical System. 2001, 2(10): 180~186
12 Meiling Zhu, Paul Kirby, Ming Yu Lim. Lagrange’s Formalism for Modeling of a Tri-axial Micro Accelerometer with Piezoelectric Thin-Film Sensing. IEEE Sensors Journal. 2004, 4(4): 455~463
13 H. Seidel, U. Fritsch, R. Gottinger and J. Schalk. A Piezoresistive Silicon Accelerometer with Monolithically Integrated CMOS-Circuitry. The 8th international conference on solid-state sensors and actuators, and Eurosensors IX, Stockholm, Sweden. 1995: 597~600
14 A. Partridge. High-Performance Planar Piezoresistive Accelerometer. Journal of Micoelectromechanical System. 2000, 4(10): 58~66
15石庚辰.微机械加速度传感器及应用.测控技术. 2003, 3(12): 5~8
16于梅芳.与硅微电子技术相兼容的传感器和执行器微细加工技术.传感器技术学报. 1995, (1): 45~48
17 Leung A.M, J. Jones, E. Czyzewska. Micromachined Accelerometer Based on Convection Heat Transfer. Proceedings of the 1998 IEEE 11th Annual International Workshop on Micro Electro Mechanical Systems, Heidelberg, German, 1998: 627~630
18 F. Mailly, A. Giani, A. Martinez et al. Micromachined Thermal Accelerometer. Sensors and Actuators. 2003,103: 359~363
19程保罗,李昕欣.带有静电自检测功能的高灵敏度加速度传感器.半导体学报. 2005, (3): 547~552
20 N. Deb, R. D. Blanton. Built-In Self Test of CMOS-MEMS Accelerometers. International Test Conference, IEEE, 2002: 1075~1083
21 J. Wu, G. K. Fedder, and L. Richard Carley. A Low-Noise Low-Offset Capacitive Sensing Amplifier for a 50μg/ Hz Monolithic CMOS MEMS Accelerometer. IEEE Journal of Solid-State Circuit. 2004: 722~730
22徐德炳. ADXL50和ADXL05型加速度计的原理及应用.电子技术应用. 1997, (5): 60~64
23翟飞飞.赵振.陈润深.双轴加速度传感器ADXL202及其应用设计.单片机与嵌入式系统应用. 2008, (10): 67~69
24孟维国.三轴加速度计ADXL330的特点及其应用.国外电子器件. 2007, (2): 47~49
25 Analog Devices Inc.. ADXL001’s datasheet.
26 N. Yazdi, K. Najafi, An Interface IC for a Capacitiveμg Accelerometer. International Solid-State Circuits Conference, San Francisco, CA, 1999: 132~133
27 H. Kulah, J. Chae, N. Yazdi, K. Najafi. Noise Analysis and Characterization of a Sigma-Delta Capacitive Microaccelerometer. IEEE Journal of Solid State Circuits. 2006, 41(2): 352~361
28 Babak Vakili Amini, Reza Abdolvand, Farrokh Ayazi,“A 4.5-mW closed-loop micro-gravity CMOS SOI accelerometer”, IEEE J. of Solid-State Circuit, vol. 41, Dec. 2006, pp.2983-2991
29吴天准,董景新,刘云峰,赵长德.梳齿式微加速度计闭环系统性能的分析与优化.仪器仪表学报. 2006, 27(3): 285~289
30 M. Tsai, C. Wang, C. Sun, and Weileun Fang. A Novel out-of-plane Accelerometer with Fully-Differential Sensing Circuit and Sub-Micron GAP. IEEE Solid-State Sensors, Actuators and Microsystems Conference, 2007: 1487~1490
31陈渝,郁发新,王慧泉.电容式力平衡加速度计的设计.传感器技术学报. 2006, 19(2): 411~414
32汪浩.电容式为加速度计检测原理与设计分析.巢湖学院学报. 2005, 7(3): 87~89
33 X.Ji, S.Wang and Y.Xu. Performance Analysis on Captive Silicon Microaccelerometer System. Journal of Southeast University. 2006, 22(1): 69~72
34朱武,张佳民.微小差分电容检测技术的研究.测试技术学报. 2004, (3): 203~206
35 B. V. Amini, F. Ayazi. A 2.5-V 14-bitΣ-ΔCMOS SOI Capacitive Accelerometer. IEEE Journal of Solid-State Circuits. 2004, 39:2467~2476
36张德,何晓平.电容式微加速度传感器转换电路设计.电子学与光电子学. 2003: 284~285
37 Navid Yazdi, Haluk Kulah, Khalil Najafi. Precision Readout Circuits for Capacitive Microaccelerometers. Sensors. 2004,7(1):24~27
38 Howard. R.M. Low Noise Amplifier Design and Low Noise Amplifiers for Characterizing the Low Frequency Noise of Infrared Detectors. Optoelectronic and Microelectronic Materials Devices, 1998. Proceedings. 1998 Conference. 1998: 179~182
39 M.Kraft, C.P.Lewis, T.G.Hesketh. Closed-loop silicon accelerometers. Circuits, Devices and Systems. 1998,145(7):325~331
40 S.J.Sherman, W.K.Tsang, T.A.Core, D.E.Quinn. A low cost Monolithic accelerometer. 1992 Symposium on VLSI Circuits Digest of Technical Papers. 1992:34~35
41陈宇晓,刘昌孝.电容式微机械静电伺服加速度模型建立.探测与控制学报. 2003, 25(1): 29~33
42 P.Rahikkala, L.Aaltonen, K.Halonen. A fully integrated Gm-C oscillator for readout of a force balanced accelerometer. Baltic Electronics Conference, 2006International. 2006:1~4
43 T. B. Gabrielson. Mechanical-thermal Noise in Micromachined Acoustic and Vibration Sensors. IEEE Transactions on Electron Devices. 1993, 40(5): 903-909
44 Z. Djuric. Noise Sources in Microelectromechanical Systems. Proc.22nd International Conference on Microelectronics. 2000, 1:14~17
45 T. Gabtielson. Mechanical-thermal Noise in Micromachined Acoustic and Vibration Sensors. IEEE Transactions on electron devices. 1993,40(5):903~909
46 J. Chen, X. Ni. B. Mo. A Low Noise CMOS Charge Sensitive Preamplifier for MEMS Capacitive Accelerometer readout ASIC. 2007 ASICON '07 7th International Conference on 2007:490~493
47 M.Steyaert, Z.Y.Chang, W.Sansen. Low-noise Monolithic Amplifier Design: Bipolar versus CMOS. Analog Integrated Circuits and Signal Processing. 1991,(1):10~12
2金铃. MEMS技术研究及应用.现代雷达. 2004, 26(l2): 26～29
3李学东,余志伟.基于MEMS技术的微型传感器.仪表技术与传感器. 2005, 9: 4～7
4林俊.微电机系统(MEMS)的测试问题.国外电子测量技术. 2005, 8: 3～3
5 K. H. L. Chau, S. R. Lewis, Y. Zhao, et al.. An Integrated Force-balanced Capacitive Accelerometer for Low-G Applications. Sensors and Actuators A. 1996, 472~476
6 M. Tanaka. An Industrial and Applied Review of New MEMS Devices Features. Microelectronic Engineering. 2007, 84: 1341~1344
7 N. Barbour, J. Gilmore, et al.. Micromechanical Silicon Instrument and Systems Development at Draper Laboratory. AIAA Guidance, Navigation and Technology Conference, San Diego, 1996: 29~31
8 N. Yazdi, F. Ayazi, K. Najafi. Micromachined Inertial Sensors. Proceedings of the IEEE. 1998, 86(8): 1640~1659
9华冠雄译.惯性传感器技术的发展趋势.自动驾驶仪与红外技术. 2002, (2): 36~45
10 Applied MEMS Inc. An Extremely Low-Noise Micromachined Accelerometer with Custom ASIC circuitry. Sensors. 2001, 18(5): 52~56
11 Don L, DeVoe. Surface Micromachined Piezoelectric Accelerometers. Journal of Micoelectromechanical System. 2001, 2(10): 180~186
12 Meiling Zhu, Paul Kirby, Ming Yu Lim. Lagrange’s Formalism for Modeling of a Tri-axial Micro Accelerometer with Piezoelectric Thin-Film Sensing. IEEE Sensors Journal. 2004, 4(4): 455~463
13 H. Seidel, U. Fritsch, R. Gottinger and J. Schalk. A Piezoresistive Silicon Accelerometer with Monolithically Integrated CMOS-Circuitry. The 8th international conference on solid-state sensors and actuators, and Eurosensors IX, Stockholm, Sweden. 1995: 597~600
14 A. Partridge. High-Performance Planar Piezoresistive Accelerometer. Journal of Micoelectromechanical System. 2000, 4(10): 58~66
15石庚辰.微机械加速度传感器及应用.测控技术. 2003, 3(12): 5~8
16于梅芳.与硅微电子技术相兼容的传感器和执行器微细加工技术.传感器技术学报. 1995, (1): 45~48
17 Leung A.M, J. Jones, E. Czyzewska. Micromachined Accelerometer Based on Convection Heat Transfer. Proceedings of the 1998 IEEE 11th Annual International Workshop on Micro Electro Mechanical Systems, Heidelberg, German, 1998: 627~630
18 F. Mailly, A. Giani, A. Martinez et al. Micromachined Thermal Accelerometer. Sensors and Actuators. 2003,103: 359~363
19程保罗,李昕欣.带有静电自检测功能的高灵敏度加速度传感器.半导体学报. 2005, (3): 547~552
20 N. Deb, R. D. Blanton. Built-In Self Test of CMOS-MEMS Accelerometers. International Test Conference, IEEE, 2002: 1075~1083
21 J. Wu, G. K. Fedder, and L. Richard Carley. A Low-Noise Low-Offset Capacitive Sensing Amplifier for a 50μg/ Hz Monolithic CMOS MEMS Accelerometer. IEEE Journal of Solid-State Circuit. 2004: 722~730
22徐德炳. ADXL50和ADXL05型加速度计的原理及应用.电子技术应用. 1997, (5): 60~64
23翟飞飞.赵振.陈润深.双轴加速度传感器ADXL202及其应用设计.单片机与嵌入式系统应用. 2008, (10): 67~69
24孟维国.三轴加速度计ADXL330的特点及其应用.国外电子器件. 2007, (2): 47~49
25 Analog Devices Inc.. ADXL001’s datasheet.
26 N. Yazdi, K. Najafi, An Interface IC for a Capacitiveμg Accelerometer. International Solid-State Circuits Conference, San Francisco, CA, 1999: 132~133
27 H. Kulah, J. Chae, N. Yazdi, K. Najafi. Noise Analysis and Characterization of a Sigma-Delta Capacitive Microaccelerometer. IEEE Journal of Solid State Circuits. 2006, 41(2): 352~361
28 Babak Vakili Amini, Reza Abdolvand, Farrokh Ayazi,“A 4.5-mW closed-loop micro-gravity CMOS SOI accelerometer”, IEEE J. of Solid-State Circuit, vol. 41, Dec. 2006, pp.2983-2991
29吴天准,董景新,刘云峰,赵长德.梳齿式微加速度计闭环系统性能的分析与优化.仪器仪表学报. 2006, 27(3): 285~289
30 M. Tsai, C. Wang, C. Sun, and Weileun Fang. A Novel out-of-plane Accelerometer with Fully-Differential Sensing Circuit and Sub-Micron GAP. IEEE Solid-State Sensors, Actuators and Microsystems Conference, 2007: 1487~1490
31陈渝,郁发新,王慧泉.电容式力平衡加速度计的设计.传感器技术学报. 2006, 19(2): 411~414
32汪浩.电容式为加速度计检测原理与设计分析.巢湖学院学报. 2005, 7(3): 87~89
33 X.Ji, S.Wang and Y.Xu. Performance Analysis on Captive Silicon Microaccelerometer System. Journal of Southeast University. 2006, 22(1): 69~72
34朱武,张佳民.微小差分电容检测技术的研究.测试技术学报. 2004, (3): 203~206
35 B. V. Amini, F. Ayazi. A 2.5-V 14-bitΣ-ΔCMOS SOI Capacitive Accelerometer. IEEE Journal of Solid-State Circuits. 2004, 39:2467~2476
36张德,何晓平.电容式微加速度传感器转换电路设计.电子学与光电子学. 2003: 284~285
37 Navid Yazdi, Haluk Kulah, Khalil Najafi. Precision Readout Circuits for Capacitive Microaccelerometers. Sensors. 2004,7(1):24~27
38 Howard. R.M. Low Noise Amplifier Design and Low Noise Amplifiers for Characterizing the Low Frequency Noise of Infrared Detectors. Optoelectronic and Microelectronic Materials Devices, 1998. Proceedings. 1998 Conference. 1998: 179~182
39 M.Kraft, C.P.Lewis, T.G.Hesketh. Closed-loop silicon accelerometers. Circuits, Devices and Systems. 1998,145(7):325~331
40 S.J.Sherman, W.K.Tsang, T.A.Core, D.E.Quinn. A low cost Monolithic accelerometer. 1992 Symposium on VLSI Circuits Digest of Technical Papers. 1992:34~35
41陈宇晓,刘昌孝.电容式微机械静电伺服加速度模型建立.探测与控制学报. 2003, 25(1): 29~33
42 P.Rahikkala, L.Aaltonen, K.Halonen. A fully integrated Gm-C oscillator for readout of a force balanced accelerometer. Baltic Electronics Conference, 2006International. 2006:1~4
43 T. B. Gabrielson. Mechanical-thermal Noise in Micromachined Acoustic and Vibration Sensors. IEEE Transactions on Electron Devices. 1993, 40(5): 903-909
44 Z. Djuric. Noise Sources in Microelectromechanical Systems. Proc.22nd International Conference on Microelectronics. 2000, 1:14~17
45 T. Gabtielson. Mechanical-thermal Noise in Micromachined Acoustic and Vibration Sensors. IEEE Transactions on electron devices. 1993,40(5):903~909
46 J. Chen, X. Ni. B. Mo. A Low Noise CMOS Charge Sensitive Preamplifier for MEMS Capacitive Accelerometer readout ASIC. 2007 ASICON '07 7th International Conference on 2007:490~493
47 M.Steyaert, Z.Y.Chang, W.Sansen. Low-noise Monolithic Amplifier Design: Bipolar versus CMOS. Analog Integrated Circuits and Signal Processing. 1991,(1):10~12