STUDY OF THE DIGITAL CAPACITANCE TO FREQUENCY CONVERTER FOR THE DATA PROCESSING SYSTEMS OF MICROMECHANICAL ACCELEROMETERS-GYROSCOPES
Abstract
Microelectromechanical systems (MEMS) are based on the use of micromechanical components
implemented using microelectronic technologies. MEMS gyroscopes and accelerometers are
widespread, and they are implemented as a stackable design because of the joint implementation
complexity of mechanical sensor and data processing system, which converts sensor’s output signals
to digital or analog signal, in one technological process. One of the causes of this configuration
outspread is the use of analog circuitry elements in data processing devices, the implementation
of which in integrated form does not contribute to solving the problem. Furthermore using of
two process flows in sensors manufacturing increases sensors self-cost substantially. This paper
presents the research results of the digital capacitance-to-frequency converter, technology of
which is compatible with the surface micromachining technology of the integrated micromechanical
sensors. The output data of this converter is the frequency of the digital signal that needs to be
measured and converted to binary code. To solve this problem, a low-power digital frequency
meter was researched, and the implementation of a digital converter and frequency counter as a
device for the primary processing of data from gyroscopes-accelerometers was also considered.
The dependence of the frequency value of the converter’s output signal F on the capacitance C_x
was obtained; frequency variation was 0-13.5 MHz while capacitance was changed from 0 to
50 fF. The dependences of the range of the measured frequency of the frequency meter on thecounter capacity 1-10 and the clock generator frequencies 0.25, 0.5 1 GHz were obtained, as well as dependencies of the frequency meter power consumption 18-60 μW on the clock generator
frequencies 0.25-1 GHz.
References
posobie [Microelectromechanical systems: tutorial]. Petrozavodsk: Izd-vo PetrGU, 2016, 171 p.
2. Shelepin N.A. Kremnievye mikrosensory i mikrosistemy: ot bytovoy tekhniki do aviatsionnykh
priborov [Silicon microsensors and microsystems: from household appliances to aviation devices],
Mikrosistemnaya tekhnika [Microsystem technology], 2000, No. 1, pp. 40-43.
3. Sicard E., Bendhia S.D. Basics of CMOS Cell Design. McGraw-Hill, 2007, 427 p.
4. Erişmiş M.A. Mems accelerometers and gyroscopes for inertial measurement units. Department
of Electrical and Electronics Engineering, 2004, 137 p.
5. Xie H. Gyroscope and micromirror design using vertical-axis CMOS-MEMS actuation and
sensing. Carnegie Mellon university, 2002, 246 p.
6. Elwenspoek M., Wiegerink R. Mechanical microsensors. Springer, 2001, 308 p.
7. Prokof'ev I.V., Tikhonov R.D. Nano- i mikrosistemy dlya monitoringa parametrov dvizheniya
transportnykh sredstv [Nano- and microsystems for monitoring parameters of the movement of
vehicles], Nano- i mikrosistemnaya tekhnika [Nano- and microsystem technology], 2011,
No. 12, pp. 48-50.
8. Raspopov V.Ya. Mikromekhanicheskie pribory [Micromechanical devices]. Moscow:
Mashinostroenie, 2007, 400 p.
9. Ghodssi R., Lin P. MEMS Materials and Processes Handbook. Berlin: Springer, 2011, 1185 p.
10. MEMS-datchiki dvizheniya ot STMicroelectronics: akselerometry i giroskopy [MEMS motion
sensors from STMicroelectronics: accelerometers and gyroscopes], Vremya elektroniki [Electronics
time]. Available at: http://www.russianelectronics.ru/leader-r/review/2193/doc/48456/
(accessed 28 February 2018).
11. MEMS market: 17.5% CAGR between 2018 and 2023. www.i-micronews.com. Available at:
https://www.i-micronews.com/mems-market-17-5-cagr-between-2018-and-2023/ (accessed 15
May 2019).
12. Akselerometr kompanii STMicroelectronics [Accelerometer from STMicroelectronics],
LIS344ALH, MEMS inertial sensor high performance 3-axis ±2/±6g ultracompact linear accelerometer,
STMicroelectronics. Available at: https://www.st.com/resource/en/datasheet/
lis344alh.pdf (accessed 25 November 2018).
13. Akselerometr kompanii STMicroelectronics [Accelerometer from STMicroelectronics], LIS3DSH,
MEMS digital output motion sensor: ultra-low-power high-performance three-axis "nano" accelerometer/
STMicroelectronics. Available at: https://www.st.com/resource/en/datasheet/
lis3dsh.pdf (accessed 25 November 2018).
14. Akselerometr kompanii Analog Devices [Accelerometer from Analog Devices], ADXL1003,
Low Noise, Wide Bandwidth, MEMS Accelerometer, Analog Devices. Available at:
https://www.analog.com/ru/products/adxl1003.html (accessed 25 November 2018).
15. Giroskop kompanii Analog Devices [Gyroscope from Analog Devices], ADXRS645, High
Temperature, Vibration Rejecting ±2000°/sec Gyroscope, Analog Devices. Available at:
https://www.analog.com/ru/products/adxrs645.html (accessed 25 November 2018).
16. Konoplev B.G., Ryndin E.A. Vysokochuvstvitel'nyy preobrazovatel' emkosti v chastotu [Highly
sensitive capacitor to frequency converter]. Patent RF No. 2602493, 01.09.2015.
17. Konoplev B.G., Popov A.O. tsifrovoy chastotomer dlya malomoshchnykh integral'nykh skhem
[Digital frequency meter for low-power integrated circuits]. Patent RF No. 187313,
01.03.2019.
18. Popov A.O., Sinyukin A.S. Design of Frequency Meter Unit for Low-Power Integrated Circuits,
International Journal of Research Studies in Electrical and Electronics Engineering
(IJRSEEE), 2017, No. 3.
19. Sicard E. Microwind & DSCH v3.5 – Lite User’s Manual. Toulouse, France: INSA Toulouse,
2009, 130 p.
20. Sicard E., Bendhia S.D. Advanced CMOS Cell Design. 2nd ed. McGraw-Hill, 2007, 364 p.
21. Nanotekhnologii v mikroelektronike [Nanotechnology in microelectronics], ed. by O.A.
Ageeva, B.G. Konopleva. Moscow: Nauka, 2019, 511 p.
