TLC5955 Datasheet, PDF (15/53 Pages) Texas Instruments – TLC5955 48-Channel, 16-Bit, PWM LED Driver with DC, BC, LED Open-Short Detection, and Internal Current Setting

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8 Detailed Description
TLC5955
SBVS237 – MARCH 2014
8.1 Overview
The TLC5955 is 48-channel, 30-mA, constant-current LED driver that can control LED on-time with pulse width
modulation (PWM) in 65,536 steps for grayscale (GS) control. A maximum of 281 trillion colors can be generated
with red, green, and blue LEDs connected to the constant-current outputs.
The device has a 128-step, 7-bit, output current control function called dot correction (DC) that can control each
constant-current output. Inherently, LED lamps have different intensities resulting from manufacturing differences.
The DC function can reduce the inherent differences in intensity and improve LED lamp brightness uniformity.
The device also has a 128-step, 7-bit, output current control function called global brightness control (BC) that
can control each color group output. The BC function can adjust the red, green, and blue LED intensity for true
white with constant-current control. The device contributes higher image quality to LED displays with fine white
balance tuning by using these GS, DC, and BC functions.
The display controller can locate LED lamp failures via the device because the controller can detect LED lamp
failures with the LED open detection (LOD) and LED short detection (LSD) functions and the reliability of the
display can be improved by the LOD, LSD function.
The device maximum constant-current output value can be set by internal register data instead of the general
method of using an external resistor setting. Thus, any failure modes that occur from the external resistor can be
eliminated and one resistor can be eliminated.
The device constant-current output can drive approximately 19 mA at a 0.25-V output voltage and a +25°C
ambient temperature. This voltage is called knee voltage. This 0.25-V, low-knee voltage can contribute to the
design of a lower-power display system. The total number of LED drivers on one LED display panel can be
reduced because 48 LED lamps can be driven by one LED driver. Therefore, designing fine-pitch LED displays is
simplified.
Copyright © 2014, Texas Instruments Incorporated
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