TCS230
PROGRAMMABLE
COLOR LIGHTTOFREQUENCY CONVERTER
TAOS046 – JANUARY 2003
1
The
LUMENOLOGY
Company
Copyright 2003, TAOS Inc.
www.taosinc.com
High-Resolution Conversion of Light
Intensity to Frequency
Programmable Color and Full-Scale Output
Frequency
Communicates Directly With a Microcontroller
Single-Supply Operation (2.7 V to 5.5 V)
Power Down Feature
Nonlinearity Error Typically 0.2% at 50 kHz
Stable 200 ppm/°C Temperature Coefficient
Low-Profile Surface-Mount Package
Description
The TCS230 programmable color light-to-frequency converter combines configurable silicon photodiodes and
a current-to-frequency converter on single monolithic CMOS integrated circuit. The output is a square wave
(50% duty cycle) with frequency directly proportional to light intensity (irradiance). The full-scale output
frequency can be scaled by one of three preset values via two control input pins. Digital inputs and digital output
allow direct interface to a microcontroller or other logic circuitry. Output enable (OE) places the output in the
high-impedance state for multiple-unit sharing of a microcontroller input line.
The light-to-frequency converter reads an 8 x 8 array of photodiodes. Sixteen photodiodes have blue filters, 16
photodiodes have green filters, 16 photodiodes have red filters, and 16 photodiodes are clear with no filters.
The four types (colors) of photodiodes are interdigitated to minimize the effect of non-uniformity of incident
irradiance. All 16 photodiodes of the same color are connected in parallel and which type of photodiode the
device uses during operation is pin-selectable. Photodiodes are 120 µm x 120 µm in size and are on 144-µm
centers.
Functional Block Diagram
Light
Current-to-Frequency
Converter
Photodiode
Array
S2 S3 S0 S1
OE
Output
Texas Advanced Optoelectronic Solutions Inc.
800 Jupiter Road, Suite 205 Plano, TX 75074 (972) 673-0759
8 S3
7 S2
6 OUT
5 V
DD
SOIC PACKAGE
(TOP VIEW)
SO 1
S1 2
OE
3
GND 4
