A Low-Power Compressive Sampling (CS) Photoplethysmogram (PPG) Readout with Embedded Feature Extraction

  • Venkata Rajesh Pamula
  • Chris Van Hoof
  • Marian Verhelst
Part of the Analog Circuits and Signal Processing book series (ACSP)


A compressive sampling (CS) photoplethysmogram (PPG) readout ASIC with embedded feature extraction to estimate heart rate (HR) directly from compressively sampled data is presented in this chapter. The ASIC incorporates a low-power analog front end (AFE), comprising of a transimpedance amplifier (TIA), switched integrator (SI), and a 12-bit successive approximation register (SAR) analog-to-digital converter (ADC) together with a digital back end (DBE) with embedded feature extraction unit (FEU) to estimate the average heart rate (HR) over a 4 s interval directly from compressively sampled PPG data. Trade-offs involved in TIA design for PPG readouts, in terms of stability, noise, and power consumption, are discussed in detail. The implemented ASIC supports uniform sampling mode (1 × compression) as well as CS modes with compression ratios of 8 ×, 10 ×, and 30 ×. Feature extraction to estimate the average HR is performed using least-squares spectral fitting through lomb-Scargle periodogram (LSP). The ASIC, implemented in a 0.18 μm CMOS process, consumes 172 μW of power from a 1.2 V supply while reducing the relative LED driver power consumption by up to 30 times without significant loss of relevant information for accurate HR estimation.


  1. 16.
    E.S. Winokur, Single-site, noninvasive, blood pressure measurements at the ear using ballistocardiogram (BCG), and photoplethysmogram (PPG), and a low-power, reflectance-mode PPG SoC, Ph.D. dissertation, Massachusetts Institute of Technology, 2014Google Scholar
  2. 20.
    K.N. Glaros, Low-power pulse oximetry and transimpedance amplifiers, Ph.D. dissertation, Imperial College London, 2011Google Scholar
  3. 35.
    ANSI/AAMI-EC13, American national standards for cardiac monitors, heart rate meters and alarms (2002)Google Scholar
  4. 37.
    G.B. Moody, R.G. Mark, MIT-BIH arrhythmia database (1992) [Online]. Available:
  5. 101.
    V.R. Pamula, J.M. Valero-Sarmiento, L. Yan, A. Bozkurt, C. Van Hoof, N. Van Helleputte, R.F. Yazicioglu, M. Verhelst, A 172μW compressively sampled photoplethysmographic (PPG) readout ASIC with heart rate estimation directly from compressively sampled data. IEEE Trans. Biomed. Circuits Syst. 11(3), 487–496 (2017)CrossRefGoogle Scholar
  6. 102.
    G. Koklu, R. Etienne-Cummings, Y. Leblebici, G.D. Micheli, S. Carrara, Characterization of standard CMOS compatible photodiodes and pixels for lab-on-chip devices, in 2013 IEEE International Symposium on Circuits and Systems (ISCAS2013) (May 2013), pp. 1075–1078Google Scholar
  7. 103.
    Product sheet for Nellcor™reusable SpO2 sensors with Oximax™technology [Online]. Available:
  8. 104.
    P.R. Gray, R.G. Meyer, Analysis and Design of Analog Integrated Circuits (Wiley, New York, 1990)Google Scholar
  9. 105.
    M. Tavakoli, L. Turicchia, R. Sarpeshkar, An ultra-low-power pulse oximeter implemented with an energy-efficient transimpedance amplifier. IEEE Trans. Biomed. Circuits Syst. 4(1), 27–38 (2010)CrossRefGoogle Scholar
  10. 106.
    A.K. Wong, K.-P. Pun, Y.-T. Zhang, K.N. Leung, A low-power CMOS front-end for photoplethysmographic signal acquisition with robust DC photocurrent rejection. IEEE Trans. Biomed. Circuits Syst. 2(4), 280–288 (2008)CrossRefGoogle Scholar
  11. 107.
    W. Wattanapanitch, M. Fee, R. Sarpeshkar, An energy-efficient micropower neural recording amplifier. IEEE Trans. Biomed. Circuits Syst. 1(2), 136–147 (2007)CrossRefGoogle Scholar
  12. 108.
    H. Wu, Y.P. Xu, A 1V 2.3 μW biomedical signal acquisition IC, in 2006 IEEE International Solid State Circuits Conference - Digest of Technical Papers (Feb 2006), pp. 119–128Google Scholar
  13. 109.
    M. Alhawari, N. Albelooshi, M.H. Perrott, A 0.5 V <  4μW CMOS photoplethysmographic heart-rate sensor IC based on a non-uniform quantizer, in 2013 IEEE International Solid-State Circuits Conference Digest of Technical Papers (IEEE, Piscataway, 2013), pp. 384–385Google Scholar
  14. 110.
    E.S. Winokur, T. O’Dwyer, C.G. Sodini, A low-power, dual-wavelength photoplethysmogram (PPG) SoC with static and time-varying interferer removal. IEEE Trans. Biomed. Circuits Syst. 9(4), 581–589 (2015)CrossRefGoogle Scholar

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© Springer Nature Switzerland AG 2019

Authors and Affiliations

  • Venkata Rajesh Pamula
    • 1
  • Chris Van Hoof
    • 1
  • Marian Verhelst
    • 2
  1. 1.imecLeuvenBelgium
  2. 2.KU Leuven ESAT-MICASLeuvenBelgium

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