High Resolution CMOS Frequency-to-digital Converter for a Fine Dust Sensor using a MEMS Resonator

다국어 초록 (Multilingual Abstract)

A high resolution, low power CMOS oscillator and frequency-to-digital converter for a fine dust sensor using a MEMS resonator is proposed. The proposed frequency-to-digital converter is realized based on dual-loop hybrid delay-locked loop to distinguish fine frequency variations according to very small fine dust concentrations, and simultaneously applied binary and square search algorithms to obtain accurate digital codes indicating frequency changes. An oscillator and frequency-todigital converter for a fine dust sensor is implemented using the 0.18-μm CMOS process. The core size of the fabricated MEMS oscillator and frequency-to-digital converter is 0.9 mm2 and consumes about 16 mW of power at 1.8 V supply voltage. The proposed frequency-to-digital converter covers the input frequency range of 1.7 GHz to 2.3 GHz with 1 bit resolution of about 3 MHz.

참고문헌 (Reference)

1 C-H. Huang, "Relative humidity effect on PM 2. 5 readings recorded by collocated beta attenuation monitors" 25 (25): 1079-1090, 2008

2 B. Razavi, "RF Microelectronics" Prentice-Hall 1998

3 J. R. Patts, "Performance Comparison of Real-Time Light Scattering Dust Monitors Across Dust Types and Humidity Levels. Mining" 36 (36): 741-749, 2019

4 S. B. Paril, "Mass Sensing using an Amorphous Silicon MEMS resonator" 1 (1): 1063-1066, 2009

5 J-S. Choi, "MEMS particle sensor based on resonant frequency shifting" 8 (8): 2020

6 J. Lee, "Linearly frequency-tunable and low-phase noise ring VCO using varactors with optimally-spaced bias voltages" 54 (54): 342-343, 2018

7 박선의 ; 김주엽 ; 박한기 ; 방주은 ; 신유환 ; 최재혁, "Frequency discriminator for the fine dust sensor" 반도체설계교육센터 7 (7): 26-31, 2021

8 Z. Wang, "Comparison of real-time instruments and gravimetric method when measuring particulate matter in a residential building" 66 (66): 1109-1120, 2016

9 J. Bjurstrom, L. Vestling, J. Olsson and I. Katardjiev, "An accurate direct extraction technique for the MBVD resonator model" 1241-1244, 2004

10 P. Mittal, "A successive approximation register based digital delay locked loop for clock and data recovery circuits" Indraprastha Institute of Information Technology 2018

11 Jongsun KIM ; Sangwoo Han, "A High-Resolution Dual-Loop Digital DLL" 대한전자공학회 16 (16): 520-527, 2016