ULTRA LOW POWER CIRCUITS FOR WEARABLE BIOMEDICAL SENSORS

Abstract

THE MAIN RESEARCH TOPIC IS DESIGNING HIGH-PERFORMANCE ENERGY-EFFICIENT CIRCUITS FOR WEARABLE SENSORS, WHICH CAPTURE AND PROCESS BIOMEDICAL SIGNALS SUCH AS ELECTROCARDIOGRAM (ECG) AND RESPIRATORY RATE FOR TELEMEDICINE AND PREVENTIVE HEALTHCARE SERVICE. NEW PSEUDO RESISTORS ARE PROPOSED TO AVOID ATTENUATING SUB-0.1 HZ SIGNAL WITH < 0.4 % DISTORTIONS AT 3 V OUTPUT. A POSITIVE FEEDBACK LOOP FOR AC-COUPLED ANALOG FRONT-END (AFE) IMPROVES THE INPUT IMPEDANCE AND HENCE THE SIGNAL QUALITY. ALSO, A DC-COUPLED AFE FEATURING 4 GΩ INPUT IMPEDANCE IS DESIGNED FOR DRY-ELECTRODE ECG SENSING. THE ENERGY EFFICIENCY OF THE SENSOR SYSTEM IS ENHANCED BY INTEGRATING SIGNAL PROCESSING TASKS INTO THE ANALOG-TO-DIGITAL CONVERTER (ADC). BASED ON LEVEL-CROSSING SAMPLING WITH DELTA MODULATION, A 220-NW EVENT-DRIVEN ADC WITH QRS DETECTION FUNCTION IS INTRODUCED. INTEGRATED WITH ULTRA-WIDEBAND TRANSMITTER, THE WIRELESS ECG SENSOR CONSUMES LESS THAN 3 μW UNDER FULL-RATE TRANSMISSION. ALL THE PRESENTED