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Proceedings Paper

An ultra-low-power ambient light sensor for portable devices
Author(s): Soon-Ik Cho; Yun-Jeong Kim; Jong-Ho Lee; Kwang-Hyun Baek; Suki Kim
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Paper Abstract

Power management is one of the most important issues in portable electronics like cell phone, PDA, UMPC, GPS, MP3 player and laptop computer. Ambient Light Sensors are getting popular as a most effective solution to extend battery lifetime for these devices. This paper provides basic information about ambient light sensors on a general level and introduces an ultra low-power ambient light sensor for portable electronics. The implemented ambient light sensor converts light illuminance to 5-digital codes every 300ms which can measure illuminance from 10 to 1000 Lux consuming only 5uA. An IR-reject optical filter and a built-in integrating analog-to-digital converter reduce influences of infrared ray and 50Hz/60Hz noise from artificial light sources respectively. The ambient light sensor is fabricated in a standard CMOS 0.5-um process technology. Test results show that the implemented ambient light sensor has incandescent/fluorescent light sensitivity ratio around 2.3.

Paper Details

Date Published: 10 February 2009
PDF: 9 pages
Proc. SPIE 7219, Optoelectronic Integrated Circuits XI, 72190U (10 February 2009); doi: 10.1117/12.807927
Show Author Affiliations
Soon-Ik Cho, Korea Univ. (Korea, Republic of)
Yun-Jeong Kim, Korea Univ. (Korea, Republic of)
Jong-Ho Lee, The Univ. of Texas at Austin (United States)
Kwang-Hyun Baek, Chung-Ang Univ. (Korea, Republic of)
Suki Kim, Korea Univ. (Korea, Republic of)


Published in SPIE Proceedings Vol. 7219:
Optoelectronic Integrated Circuits XI
Louay A. Eldada; El-Hang Lee, Editor(s)

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