University of Tehran School of Electrical and Computer Engineering

1. University of TehranSchool of Electrical and Computer Engineering • ISSCC 2013 • Intra-Cardiac Signal-Processing IC Spring 2013 SunyoungKim et al, "A 20µW intra-cardiac signal-processing IC with 82dB bio-impedance measurement dynamic range and analog feature extraction for ventricular fibrillation detection," Solid-State Circuits Conference Digest of Technical Papers (ISSCC), 2013 IEEE International , vol., no., pp.302,303, 17-21 Feb. 2013 by: Yasser Rezaeiyan

2. Cardiac biologic system Intracardiac electrogram ECG J.G. Webster,”Design of Cardiac Pacemaker” , IEEE PRESS 1998. 1/12

3. Importance of Intra-Cardiac SP • The accurate recognition of multiple intra-cardiac signals is becoming more and more important for: • Cardiac Resynchronization Therapy (CRT) • the analysis of the intra-thoracic fluid status • But for Cardiac pacemaker • Robust and accurate heart rate (HR) at the right/left ventricles and right atrium • But for the intra-cardiac rhythm analysis • accurate motion sensor • thoracic impedance measurement SunyoungKim et al, "A 20µW intra-cardiac signal-processing IC with 82dB bio-impedance measurement dynamic range and analog feature extraction for ventricular fibrillation detection," Solid-State Circuits Conference Digest of Technical Papers (ISSCC), 2013 IEEE International , vol., no., pp.302,303, 17-21 Feb. 2013 J.G. Webster,”Design of Cardiac Pacemaker” , IEEE PRESS 1998. 2/12

4. Cardiac Pacemaker • Implantable Cardiac pacemaker Requirement: • Ultra Low Power 7-10 years life time • High Accuracy intra cardiac Signal Analysis • Small System delay < 10 ms • Small Size SunyoungKim et al, "A 20µW intra-cardiac signal-processing IC with 82dB bio-impedance measurement dynamic range and analog feature extraction for ventricular fibrillation detection," Solid-State Circuits Conference Digest of Technical Papers (ISSCC), 2013 IEEE International , vol., no., pp.302,303, 17-21 Feb. 2013 J.G. Webster,”Design of Cardiac Pacemaker” , IEEE PRESS 1998. 3/12

5. Analog signal processing IC • It consists of: • 3 power-efficient intra-cardiac signal readout channels • An ultra-low-power readout circuit for an external accelerometer(RA) • Two quadrature bio-impedance readout channels • Digitized sinusoidal current generator • Accurate • Wide dynamic range SunyoungKim et al, "A 20µW intra-cardiac signal-processing IC with 82dB bio-impedance measurement dynamic range and analog feature extraction for ventricular fibrillation detection," Solid-State Circuits Conference Digest of Technical Papers (ISSCC), 2013 IEEE International , vol., no., pp.302,303, 17-21 Feb. 2013 4/12

6. Intra-thoracic fluid analysis requires • purely sinusoidal current source • Resolve bio-impedance down to a mΩ-range change (AC) superimposed on up to a kΩ-range average (DC) impedance • This approach consumes many mWs of power • μW-range power consumption can be achieved by • square-wave current combined with quadrature demodulation • intolerable measurement errors as high as 23% SunyoungKim et al, "A 20µW intra-cardiac signal-processing IC with 82dB bio-impedance measurement dynamic range and analog feature extraction for ventricular fibrillation detection," Solid-State Circuits Conference Digest of Technical Papers (ISSCC), 2013 IEEE International , vol., no., pp.302,303, 17-21 Feb. 2013 5/12

7. Current Generator • 16-level quantized-sinusoidal current source • Suppresses all harmonics’ power below the 63rdharmonic: • High resolution with high THD • Low power consumption • Benefits of this approach: • Maximize the power efficiency • Mitigate the AC current mismatch • Simply adjust the current magnitude (10–40μAp-p) SunyoungKim et al, "A 20µW intra-cardiac signal-processing IC with 82dB bio-impedance measurement dynamic range and analog feature extraction for ventricular fibrillation detection," Solid-State Circuits Conference Digest of Technical Papers (ISSCC), 2013 IEEE International , vol., no., pp.302,303, 17-21 Feb. 2013 6/12

8. Bio-impedance readout channel • Quadrature demodulation • Extract both DC and AC bio-impedance • Offset of the QIRC may affect the accuracy of the DC bio-impedance calculation that resolve with Multi-Purpose Chopper • These offset values are calibrated in the DSP • 97% accuracy (THD < 3%) SunyoungKim et al, "A 20µW intra-cardiac signal-processing IC with 82dB bio-impedance measurement dynamic range and analog feature extraction for ventricular fibrillation detection," Solid-State Circuits Conference Digest of Technical Papers (ISSCC), 2013 IEEE International , vol., no., pp.302,303, 17-21 Feb. 2013 7/12

9. Programmable QRS extraction • Consumes only 426nA SunyoungKim et al, "A 20µW intra-cardiac signal-processing IC with 82dB bio-impedance measurement dynamic range and analog feature extraction for ventricular fibrillation detection," Solid-State Circuits Conference Digest of Technical Papers (ISSCC), 2013 IEEE International , vol., no., pp.302,303, 17-21 Feb. 2013 8/12

10. Conclusion • ASP IC for emerging CRT: • achieve accuracy-delay optimization for HR monitoring • programmable QRS feature extractor • Highly accurate • ultra-low-power (only 20μW when all channel are active) SunyoungKim et al, "A 20µW intra-cardiac signal-processing IC with 82dB bio-impedance measurement dynamic range and analog feature extraction for ventricular fibrillation detection," Solid-State Circuits Conference Digest of Technical Papers (ISSCC), 2013 IEEE International , vol., no., pp.302,303, 17-21 Feb. 2013 9/12

11. Trend • Pacemakers Leadless Pacemakers www.medtronic.com 10/12

12. Refrences • Sunyoung Kim et al, "A 20µW intra-cardiac signal-processing IC with 82dB bio-impedance measurement dynamic range and analog feature extraction for ventricular fibrillation detection," Solid-State Circuits Conference Digest of Technical Papers (ISSCC), 2013 IEEE International , vol., no., pp.302,303, 17-21 Feb. 2013 • J.G. Webster,”Design of Cardiac Pacemaker” , IEEE PRESS 1998. • www.medtronic.com 11/12

13. Thanks for your attention 12/12