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An Area‐Efficient Resistor‐less On‐Chip Frequency Reference for Ultra‐Low Power Real‐Time Clock Application
Author(s) -
Asano Hiroki,
Hirose Tetsuya,
Ozaki Toshihiro,
Kuroki Nobutaka,
Numa Masahiro
Publication year - 2018
Publication title -
ieej transactions on electrical and electronic engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.254
H-Index - 30
eISSN - 1931-4981
pISSN - 1931-4973
DOI - 10.1002/tee.22780
Subject(s) - resistor , electrical engineering , voltage , control theory (sociology) , electronic engineering , physics , engineering , computer science , control (management) , artificial intelligence
In this paper, we propose a fully integrated and area‐efficient resistor‐less relaxation oscillator (ROSC) for ultra‐low power real‐time clock (RTC) applications. The proposed ROSC is based on a conventional current‐mode ROSC and is modified to be an area‐efficient circuit configuration without using resistors. The proposed ROSC consists of a temperature‐compensated bias current generator (BCG), proportional to absolute temperature (PTAT) voltage source, current‐mode ROSC, shunt regulator, and output logic circuit. The BCG, PTAT voltage source, and shunt regulator are used to compensate for the temperature characteristics of the ROSC. The area of our proposed ROSC was extremely small, 0.022 mm 2 . Simulated results demonstrated that our proposed ROSC generates a 32.5 kHz clock frequency and achieves ultra‐low power dissipation of 271 nW. The temperature and voltage dependence of the oscillation frequency were 138 ppm/°C and 13.9 ppm/mV, respectively. Monte Carlo statistical simulations showed that the mean, standard deviation, and coefficient of variation are 32.3, 0.6 kHz, and 1.9%, respectively. © 2018 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.