0.5v, Ultra-low power, continuous-time light to digital converter for heartrate monitoring application using pulse oximetry technique

  • Mohammad Radwan Hawari

Student thesis: Master's Thesis


A custom 180nm CMOS integrated circuit implementing an ultra-low power, continuous-time, Light to Digital Converter (LDC) for heartrate monitoring applications is presented. Based on oximetry techniques, the system is sensitive across three orders of magnitude of light variation (4nA to 3uA) and supports a heart-rate frequency range spanning 30 to 300 beats per minute. The minimum sensitivity and power consumption specifications are an order of magnitude better than the state of the art, and are achieved through an innovative analog-to-digital conversion circuit architecture. In addition, the proposed architecture offers digital rejection of low frequency perturbations and provides a faster acquisition response than traditional analog implementations. This talk will present the proposed LDC architecture and then provide details of each of its key circuit blocks. Extensive simulations results will be presented that confirm the performance advantages of the system. Finally, the overall custom integrated circuit will be presented, including layout as well as discussion of its role within a new heart-rate monitor device being developed at Masdar Institute.
Date of Award2012
Original languageAmerican English
SupervisorAyman Shabra (Supervisor)


  • Digital counters
  • Continuous-time filters

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