TSL2550 Datasheet, PDF (1/14 Pages) List of Unclassifed Manufacturers – AMBIENT LIGHT SENSOR WITH SMBus INTERFACE

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D Converts Light Intensity to Digital Signal
D Infrared Compensation to Approximate
Human Eye Response
D Companding A/D for Wide Dynamic Range
D Rejects 50 Hz/60 Hz Lighting Ripple
D Two-Wire SMBus Serial Interface
D Single Supply Operation (2.7 V to 5.5 V)
D Low Active Power (1 mW typ)
D Power Down Mode
D Low-Profile Surface-Mount Package
TSL2550
AMBIENT LIGHT SENSOR
WITH SMBus INTERFACE
TAOS029 – SEPTEMBER 2002
PACKAGE D
8-LEAD SOIC
(TOP VIEW)
V_DD 1
NC 2
NC 3
GND 4
8 SMBData
7 NC
6 NC
5 SMBCLK
Description
The TSL2550 is a digital light sensor with a two-wire, SMBus serial interface. It combines two photodiodes and
a companding analog-to-digital converter (ADC) on a single CMOS integrated circuit to provide light
measurements over an effective 12-bit dynamic range.
The TSL2550 is designed for use with broad wavelength light sources. One of the photodiodes (Channel 0) is
sensitive to visible and infrared light, while the second photodiode (Channel 1) is sensitive primarily to infrared
light. An integrating ADC converts the photodiode currents to Channel 0 and Channel 1 digital outputs. Channel
1 digital output is used to compensate for the effect of the infrared component of ambient light on Channel 0
digital output. The ADC digital outputs of the two channels are used to obtain a value that approximates the
human eye response in the commonly used unit of Lux.
This device is intended primarily for use in applications in which measurement of ambient light is used to control
display backlighting such as laptop computers, PDAs, camcorders, and GPS systems. Other applications
include contrast control in LED signs and displays, camera exposure control, lighting controls, etc. The
integrating conversion technique used by the TSL2550 effectively eliminates the effect of flicker from
AC-powered lamps, increasing the stability of the measurement.
Functional Block Diagram
V_DD = 2.7 V to 5.5 V
Channel 0
Photodiode
Channel 1
Photodiode
Integrating
A/D Converter
Control Logic
Output Registers
Two-Wire Serial Interface
SMBCLK
SMBData
The LUMENOLOGYr Company
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Texas Advanced Optoelectronic Solutions Inc.
800 Jupiter Road, Suite 205 S Plano, TX 75074 S (972_t) 673-0759
www.taosinc.com
Copyright E 2002, TAOS Inc.
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