Switched Capacitor Filter EEET0470 Biomedical Electronics Rev.13.01 Switched Capacitor Filter

วัตถุประสงค์ ศึกษาเกี่ยวกับหลักการทำงานของสวิตช์ประจุ Copyright © S.Witthayapradit.2009 ศึกษาเกี่ยวกับหลักการทำงานของสวิตช์ประจุ การใช้งานวงจรรวมของสวิตช์ประจุ การประยุกต์ใช้กับงานทางการแพทย์

The Basic Principle of the SC Copyright © S.Witthayapradit.2009 q1 = CRv1 q2 = CRv2 Dq = q1-q2 = CR(v1-v2)

The Basic Principle of the SC Copyright © S.Witthayapradit.2009

Switched Capacitor PARAMETERS: var = 1nF C1 {var} RL 50K Vs FREQ = 1k Copyright © S.Witthayapradit.2009 PARAMETERS: var = 1nF V C1 {var} RL 50K Vs FREQ = 1k VAMPL = 0.2 VOFF = 0 Q2 CL 5nF Q1 M2 1 3 2 M1

Clock Frequency(fCLK) Copyright © S.Witthayapradit.2009 Time 0s 25us 50us V(Q2) 0V 2.5V 5.0V V(Q1)

Switched Capacitor Time 0s 1.0ms 2.0ms V(Vs:+) V(Ro:1) -200mV 0V 200mV Copyright © S.Witthayapradit.2009 Time 0s 1.0ms 2.0ms V(Vs:+) V(Ro:1) -200mV 0V 200mV 2nF 1nF 0.5nF

Inverting-Amplifier. [SC] Copyright © S.Witthayapradit.2009 Time 0s 1.0ms 2.0ms V(M1:D) V(Ro:1) -1.0V 0V 1.0V

Switched Capacitor Filter Copyright © S.Witthayapradit.2009 Source : Design with Operational Amplifiers and Analog Integrated Circuits , Sergio Franco

Low Pass Filter for EMG Signal Copyright © S.Witthayapradit.2009 1000 2000 3000 4000 5000 6000 500 1500 Sample number Rectified EMG signal [b,a]=butter(5,10/1000,'low'); filter_y=filtfilt(b,a,rec_y); plot(filter_y) xlabel('Sample number') ylabel('Low Pass Filtered EMG signal') 1000 2000 3000 4000 5000 6000 50 100 150 200 250 300 350 Sample number Low Pass Filtered EMG signal

Low Pass Filter for EMG Signal Copyright © S.Witthayapradit.2009 5th Order Unity-gain Butterworth Low Pass Filter with fC = 10Hz C4 = 390nF C5 = 33nF R4 = 100K R5 = 200K C2 = 22nF C3 = 10nF R2 = 560K R3 = 2M C1 = 82nF R1 = 200K

Switched Capacitor Filter Copyright © S.Witthayapradit.2009 5th-Order, Lowpass Filters Elliptic Response (MAX7418/MAX7421/MAX7422/MAX7425) Bessel Response (MAX7419/MAX7423) Butterworth Response (MAX7420/MAX7424) Clock-Turnable Corner Frequency (1Hz to 45kHz) Single-Supply Operation +5V (MAX7418–MAX7421) +3V (MAX7422–MAX7425) Low Power 3mA (Operating Mode) 0.2μA (Shutdown Mode) Available in 8-Pin μMAX Package Low Output Offset: ±4mV 8 pin μMAX W5mm. x L3mm.

Switched Capacitor Filter Copyright © S.Witthayapradit.2009 fCLK >> fC

Switched Capacitor Filter Copyright © S.Witthayapradit.2009 Design :- Low pass Filter , 5th-Order, fC = 10Hz , Butterworth Response , ± 2.5VCC fCLK >> fC MAX7420 MAX7420 :- k = 110 x 103 W5mm. x L3mm.

Universal Switched Capacitor Filter MF10 Copyright © S.Witthayapradit.2009 2 Filter Block on Chip 2nd Function Block 20 pin DIP Definition of Terms Modes of Operation

Universal Switched Capacitor Filter MF10 Copyright © S.Witthayapradit.2009 Definition of Terms

Universal Switched Capacitor Filter MF10 Copyright © S.Witthayapradit.2009 Modes of Operation MODE 1 :- N1 , BP , LP (datasheet : Figure7) MODE 1a :- Non-Inverting BP , LP (datasheet : Figure8) MODE 2 :- N2 , BP , LP (datasheet : Figure9) MODE 3 :- HP , BP , LP (datasheet : Figure10) MODE 3a :- HP , BP , LP and N+OpAmp (datasheet : Figure11) MODE 4 :- A , BP , LP (datasheet : Figure12) MODE 5 :- BP , LP (datasheet : Figure13) MODE 6a :- HP , LP (datasheet : Figure14) MODE 6b :- LP Inverting & Non-Inverting (datasheet : Figure15)

Design Example : Mode 1 Notch 1, Bandpass , Lowpass Copyright © S.Witthayapradit.2009 Notch 1, Bandpass , Lowpass

Design Example Band Pass Filter fO = 1kHz , BW = 50Hz HOBP = 20dB Copyright © S.Witthayapradit.2009

Universal Switched Capacitor Filter MAX263/64 Copyright © S.Witthayapradit.2009

Universal Switched Capacitor Filter MAX263/64 Copyright © S.Witthayapradit.2009

Universal Switched Capacitor Filter MAX263/64 Copyright © S.Witthayapradit.2009

Universal Switched Capacitor Filter MAX263/64 Copyright © S.Witthayapradit.2009

Universal Switched Capacitor Filter MAX263/64 Copyright © S.Witthayapradit.2009 fCLK / fO = 166.5 1 0 1 0 1 Q = 8 N =120 1 1 1 1 0 0 0

วงจรกรองแถบความถี่หยุดผ่านแบบปรับตัวสำหรับการวัดคลื่นไฟฟ้าหัวใจ Adaptive Band Stop Filter for Electrocardiograph Measurement Copyright © S.Witthayapradit.2009

วงจรกรองแถบความถี่หยุดผ่านแบบปรับตัวสำหรับการวัดคลื่นไฟฟ้าหัวใจ Adaptive Band Stop Filter for Electrocardiograph Measurement Copyright © S.Witthayapradit.2009

Design Example fCLK / fO = _____ fO = ______ Hz Q = _______ Copyright © S.Witthayapradit.2009 fCLK / fO = _____ fO = ______ Hz Q = _______ BW = _______

Exercises Band Pass Filter fO = 5kHz , Q = 5 fCLK / fO = __197.92__ Copyright © S.Witthayapradit.2009 fCLK / fO = __197.92__ fCLK = _____ kHz BW = _______

Reference Copyright © S.Witthayapradit.2009 [1] Sergio Franco , “Design with Operational Amplifiers and Analog Integrated Circuits” , Third edition , McGraw-Hill , 2002. [2] James W.Nilsson , Susan A.Riedel , “Electric Circuits” , 8th Edition , Prentice Hall , 2008. [3] Thomas L.Floyd , “Electronic Devices” , 7th Edition , Prentice Hall Inc. , 2005. [4] S.Witthayapradit , S.Chitwong , S.Tumthong , “Tracking Notch Filter For Electrocardiograph Measurement” , CCECE , 2006. [5] http://www.maxim-ic.com , application note 3845 , 2009.

Switched Capacitor Filter EEET0470 Biomedical Electronics Rev.13.01 Switched Capacitor Filter The End Q & A