Agilent ADJD-J823
Color Management Controller with
Integrated RGB Photosensor
Data Sheet
Description
The ADJD-J823 is a CMOS
mixed-signal IC with
integrated RGB photosensors
designed to be the optical
feedback device of an RGB
LED-based backlighting system.
A typical system consists of an
array of red, green and blue
(RGB) LEDs, LED drivers and
the ADJD-J823. The device
samples the light output from
the RGB LED array, processes
the color information and
adjusts the light output from
the RGB LEDs until the target
color is achieved. To achieve
this, the device integrates an
RGB photosensor array, an
analog-to-digital converter
front-end, a color data
processing logic core and a
high-resolution 12-bit PWM
output generator.
By employing a feedback
system and the ADJD-J823,
the light output produced by
the LED array maintains its
color over time and
temperature. In addition, using
a serial interface, specifying
the color of the LED array’s
light output is as simple as
picking the target color
coordinates from the CIE color
space and writing several bytes
of data to the device.
The sensitivity of the device to
light can be adjusted through
an automated process. The
PWM output signals control
the on-time duration of the
red, green and blue LEDs.
That duration is continually
adjusted in real-time to match
the light output from the RGB
LED array to the target color.
Features
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• Integrated RGB photosensor
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• Integrated color management
feedback controller
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• Serial Interface
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• Direct interface to standard I2C
EEPROM
••
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• 3-channel 12-bit PWM output –
Red, Green and Blue LED
channels
••
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• Built-in oscillator
Applications
••
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• LCD Backlighting
