LED driver, Texas Instruments, TLC5940
LED Drivers from TI Boost Video Quality in Large-Panel Signage Applications
News Release from:
07 November 2007
Texas Instruments has introduced two 16-channel, constant-current sink, light-emitting diode (LED) drivers with dot correction and grayscale on one integrated circuit (IC) for high-quality video. The drivers give designers increased system reliability and dynamic brightness control to enhance the resolution for large-panel mono-, multi- or full-color LED displays, LED signboards and display backlighting.
An extension of TI's popular TLC5940 family, the new TLC5942 and TLC5945 provide high-performance capabilities, such as analog and digital dimming, in an integrated IC for large LED displays. The TLC5942 provides 128 step dot correction to compensate for LED luminous mismatch, and allows for both grayscale control and dot correction to be accessible via separate, dedicated serial interface ports. The maximum current value of all 16 channels can be set by a single external resistor. Higher currents can be provided by paralleling channels. The TLC5945 is optimized for video displays with fast video action, such as stadium sporting events, as it provides a very fast refresh rate capability - 30-MHz data transfer rate - with no delay.
Both the TLC5942 and TLC5945 have two error detection circuits for LED open detection (LOD) and a thermal error flag (TEF). The LOD identifies a broken or disconnected LED during the display period. TEF indicates an over-temperature condition, meaning when the TEF is set, all output drivers are turned off. When the device has cooled the TEF is cleared and all output drivers are restarted.
TI also introduced today the TLC5916 and TLC5917, 8-channel LED drivers that support general-purpose LED display systems such as LED signage, automotive LED lighting, white goods, gaming machines and entertainment, and other general LED lighting applications. The devices provide constant-current control and open-load, shorted-load and over-temperature detection. Both also contain an 8-bit shift register and data latches, which convert serial input data into individual channel on/off control and group brightness.