TCS3772

COLOR LIGHT-TO-DIGITAL CONVERTER

with PROXIMITY SENSING

TAOS145B − SEPTEMBER 2012

2

r

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Copyright

E 2012, TAOS Inc.

The LUMENOLOGY

r Company

www.taosinc.com

Functional Block Diagram

SDA

INT

SCL

LDR

Wait Control

Prox

ADC

Prox Control

Prox

Data

IR LED Constant

Current Sink

Clear ADC

Prox

Integration

Upper Limit

Upper Limit

Lower Limit

Lower Limit

Interrupt

GND

Red ADC

Green ADC

Blue ADC

Clear Data

Red Data

Green Data

Blue Data

RGBC Control

Blue

Green

Red

Clear

Detailed Description

The TCS3772 is a next-generation digital color light sensor device containing four integrating analog-to-digital

converters (ADCs) that integrate currents from photodiodes. The device contains a 3

× 4 photodiode array used

for color measurements and a 1

× 4 photodiode array used for proximity measurements. Integration of all color

sensing channels occurs simultaneously. Upon completion of the conversion cycle, the conversion result is

transferred to the corresponding data registers. The transfers are double-buffered to ensure that the integrity

of the data is maintained. Communication with the device is accomplished through a fast (up to 400 kHz),

The device provides a separate pin for level-style interrupts. The interrupt feature simplifies and improves

system efficiency by eliminating the need to poll a sensor for a light intensity value. When interrupts are enabled,

an interrupt is generated when the value of a clear channel or proximity conversion is greater than an upper

threshold or less than a lower threshold. Once the interrupt is asserted, it remains asserted until cleared by the

controlling firmware. In addition, a programmable interrupt persistence filter allows the user to set the number

of consecutive clear channel or proximity conversions outside of the threshold region that are necessary to

trigger an interrupt. Interrupt thresholds and persistence filter settings are configured independently for both

clear and proximity.

Proximity detection requires only a single external IR LED. An internal LED driver can be configured to provide

a constant current sink of 12.5 mA, 25 mA, 50 mA, or 100 mA of current. No external current limiting resistor

is required. The number of proximity LED pulses can be programmed from 1 to 255 pulses. Each pulse has a

14-

μs period.