3 research outputs found
12.8 kHz Energy-Efficient Read-Out IC for High Precision Bridge Sensor Sensing System
ํ์๋
ผ๋ฌธ(๋ฐ์ฌ) -- ์์ธ๋ํ๊ต๋ํ์ : ๊ณต๊ณผ๋ํ ์ ๊ธฐยท์ ๋ณด๊ณตํ๋ถ, 2022.2. ๊น์ํ.In the thesis, a high energy-efficient read-out integrated circuit (read-out IC) for a high-precision bridge sensor sensing system is proposed. A low-noise capacitively-coupled chopper instrumentation amplifier (CCIA) followed by a high-resolution incremental discrete-time delta-sigma modulator (DTฮฮฃฮ) analog-to-digital converter (ADC) is implemented. To increase energy-efficiency, CCIA is chosen, which has the highest energy-efficiency among IA types. CCIA has a programmable gain of 1 to 128 that can amplify the small output of the bridge sensor. Impedance boosting loop (IBL) is applied to compensate for the low input impedance, which is a disadvantage of a CCIA. Also, the sensor offset cancellation technique was applied to CCIA to eliminate the offset resulting from the resistance mismatch of the bridge sensor, and the bridge sensor offset from -350 mV to 350 mV can be eliminated. In addition, the output data rate of the read-out IC is designed to be 12.8 kHz to quickly capture data and to reduce the power consumption of the sensor by turning off the sensor and read-out IC for the rest of the time. Generally, bridge sensor system is much slower than 12.8 kHz. To suppress 1/f noise, system level chopping and correlated double sampling (CDS) techniques are used. Implemented in a standard 0.13-ฮผm CMOS process, the ROICโs effective resolution is 17.0 bits at gain 1 and that of 14.6 bits at gain 128. The analog part draws the average current of 139.4 ฮผA from 3-V supply, and 60.2 ฮผA from a 1.8 V supply.๋ณธ ๋
ผ๋ฌธ์์๋ ๊ณ ์ ๋ฐ ๋ธ๋ฆฌ์ง ์ผ์ ์ผ์ฑ ์์คํ
์ ์ํ ์๋์ง ํจ์จ์ด ๋์ Read-out Integrated Circuit (read-out IC)๋ฅผ ์ ์ํ๋ค. ์ ์ก์ Capacitively-Coupled Instrumentation Amplifier (CCIA)์ ์ด์ ๊ณ ํด์๋ Discrete-time Delta-Sigma ๋ณ์กฐ๊ธฐ(DTฮฮฃฮ) ์๋ ๋ก๊ทธ-๋์งํธ ๋ณํ๊ธฐ(ADC)๋ฅผ ๊ตฌํํ์๋ค.
์๋์ง ํจ์จ์ ๋์ด๊ธฐ ์ํด IA ์ ํ ์ค ์๋์ง ํจ์จ์ด ๊ฐ์ฅ ๋์ CCIA๋ฅผ ์ ํํ์๋ค. CCIA๋ ๋ธ๋ฆฌ์ง ์ผ์์ ์์ ์ถ๋ ฅ์ ์ฆํญํ ์ ์๋ 1 ์์ 128์ ํ๋ก๊ทธ๋๋ฐ ๊ฐ๋ฅํ ์ ์ ์ด๋์ ๊ฐ์ง๋ค. CCIA์ ๋จ์ ์ธ ๋ฎ์ ์
๋ ฅ ์ํผ๋์ค๋ฅผ ๋ณด์ํ๊ธฐ ์ํด Impedance Boosting Loop (IBL)์ ์ ์ฉํ์๋ค. ๋ํ CCIA์ ์ผ์ ์คํ์
์ ๊ฑฐ ๊ธฐ์ ์ ์ ์ฉํ์ฌ ๋ธ๋ฆฌ์ง ์ผ์์ ์ ํญ ๋ฏธ์ค๋งค์น๋ก ์ธํ ์คํ์
์ ์ ๊ฑฐ ๊ธฐ๋ฅ์ ํ์ฌํ์์ผ๋ฉฐ -350mV์์ 350mV๊น์ง ๋ธ๋ฆฌ์ง ์ผ์ ์คํ์
์ ์ ๊ฑฐํ ์ ์๋ค. Read-out IC์ ์ถ๋ ฅ ๋ฐ์ดํฐ ์ ์ก๋ฅ ์ 12.8kHz๋ก ์ค๊ณํ์ฌ ๋ฐ์ดํฐ๋ฅผ ๋น ๋ฅด๊ฒ ์ฑ๊ณ ๋๋จธ์ง ์๊ฐ ๋์ ์ผ์์ read-out IC๋ฅผ ๊บผ์ ์ผ์์ ์ ๋ ฅ ์๋น๋ฅผ ์ค์ผ ์ ์๋๋ก ์ค๊ณํ์๋ค. ์ผ๋ฐ์ ์ผ๋ก ๋ธ๋ฆฌ์ง ์ผ์ ์์คํ
์ 12.8kHz๋ณด๋ค ๋๋ฆฌ๊ธฐ ๋๋ฌธ์ ์ด๊ฒ์ด ๊ฐ๋ฅํ๋ค. ํ์ง๋ง, ์ผ๋ฐ์ ์ธ CCIA๋ ์
๋ ฅ ์ํผ๋์ค ๋๋ฌธ์ ๋น ๋ฅธ ์๋์์ ์ค๊ณ๊ฐ ๋ถ๊ฐ๋ฅํ๋ค. ์ด๋ฅผ ํด๊ฒฐํ๊ธฐ ์ํด demodulate ์ฐจํ์ ์ฐํ ๋ด๋ถ๊ฐ ์๋ ์์คํ
์ฐจํ์ ์ด์ฉํด ํด๊ฒฐํ์๋ค.
1/f ๋
ธ์ด์ฆ๋ฅผ ์ต์ ํ๊ธฐ ์ํด ์์คํ
๋ ๋ฒจ ์ฐจํ ๋ฐ ์๊ด ์ด์ค ์ํ๋ง(CDS) ๊ธฐ์ ์ด ์ฌ์ฉ๋์๋ค. 0.13ฮผm CMOS ๊ณต์ ์์ ๊ตฌํ๋ read-out IC์ Effective Resolution (ER)์ ์ ์ ์ด๋ 1์์ 17.0๋นํธ์ด๊ณ ์ ์ ์ด๋ 128์์ 14.6๋นํธ๋ฅผ ๋ฌ์ฑํ์๋ค. ์๋ ๋ก๊ทธ ํ๋ก๋ 3 V ์ ์์์ 139.4ฮผA์ ํ๊ท ์ ๋ฅ๋ฅผ, ๋์งํธ ํ๋ก๋ 1.8 V ์ ์์์ 60.2ฮผA์ ํ๊ท ์ ๋ฅ๋ฅผ ์ฌ์ฉํ๋ค.CHAPTER 1 INTRODUCTION 1
1.1 SMART DEVICES 1
1.2 SMART SENSOR SYSTEMS 4
1.3 WHEATSTONE BRIDGE SENSOR 5
1.4 MOTIVATION 8
1.5 PREVIOUS WORKS 10
1.6 INTRODUCTION OF THE PROPOSED SYSTEM 14
1.7 THESIS ORGANIZATION 16
CHAPTER 2 SYSTEM OVERVIEW 17
2.1 SYSTEM ARCHITECTURE 17
CHAPTER 3 IMPLEMENTATION OF THE CCIA 19
3.1 CAPACITIVELY-COUPLED CHOPPER INSTRUMENTATION AMPLIFIER 19
3.2 IMPEDANCE BOOSTING 22
3.3 SENSOR OFFSET CANCELLATION 25
3.4 AMPLIFIER OFFSET CANCELLATION 29
3.5 AMPLIFIER IMPLEMENTATION 32
3.6 IMPLEMENTATION OF THE CCIA 35
CHAPTER 4 INCREMENTAL ฮฮฃ ADC 37
4.1 INTRODUCTION OF INCREMENTAL ฮฮฃ ADC 37
4.2 IMPLEMENTATION OF INCREMENTAL ฮฮฃ MODULATOR 40
CHAPTER 5 SYSTEM-LEVEL DESIGN 43
5.1 DIGITAL FILTER 43
5.2 SYSTEM-LEVEL CHOPPING & TIMING 46
CHAPTER 5 MEASUREMENT RESULTS 48
6.1 MEASUREMENT SUMMARY 48
6.2 LINEARITY & NOISE MEASUREMENT 51
6.3 SENSOR OFFSET CANCELLATION MEASUREMENT 57
6.4 INPUT IMPEDANCE MEASUREMENT 59
6.5 TEMPERATURE VARIATION MEASUREMENT 63
6.6 PERFORMANCE SUMMARY 66
CHAPTER 7 CONCLUSION 68
APPENDIX A. 69
ENERGY-EFFICIENT READ-OUT IC FOR HIGH-PRECISION DC MEASUREMENT SYSTEM WITH IA POWER REDUCTION TECHNIQUE 69
BIBLIOGRAPHY 83
ํ๊ธ์ด๋ก 87๋ฐ
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