June 14, 2012 — As light-emitting diodes (LEDs) replace cold-cathode fluorescent lamps (CCFLs) for backlighting of liquid crystal displays (LCDs), manufactures face LCD upgrades and supporting electronics redesigns. Endicott Research Group Inc. (ERG) developed the Smart Bridge module to quickly, easily and economically upgrade to LEDs, using the system’s existing input power signals.
Smart Bridge converts the analog dimming signal used for the inverter into a PWM signal for the LED driver. This powers the LED backlight driver without additional modifications. At Display Week this month in Boston, ERG’s Bill Abbott, corporate distribution manager, spoke with Solid State Technology about the industry need for conversion products. The move from CCFL to LED backlights is driven by RoHS legislation for many of ERG’s customers, he said. The transition adds about 10-15% to the backlight cost, but the real problem is re-qualifying a system-level design if you need to change all the supporting electronics. “LED backlights will be the standard soon,” Abbott noted. Even display makers that are exempt from RoHS will have trouble sourcing CCFLs.
A drop-in replacement to support the new backlights was important, Abbott said. Users remove the inverter, plug in the footprint-compatible Smart Bridge module, and connect the input cable from the existing power supply or controller to the Smart Bridge. The Smart Bridge module converts the Power · Ground · Enable · Control signals and mates directly to the LCD via a small harness, powering the new backlight driver correctly.
ERG currently offers three versions of the Smart Bridge module. The standard version (SBD4212F) is a Smart Bridge Pass-Through with Integrated PWM Dimming and operates from a typical 12V signal. The Smart Bridge DC-DC Converter with Integrated PWM Dimming (SBDCD4213F) is designed for applications requiring a step-up conversion from 5V to 12V. The third version is the Smart Bridge DC-DC Converter Without Dimming (SBDC4227F). The Smart Bridge modules are available in the footprint of most inverters, and custom footprints are available.
ERG also makes edge-light LED strips as drop-in replacement backlights. These meet or exceed the brightness of legacy CCFLs. Downtime to upgrade a display is minimal.
For more information, contact Endicott Research Group (ERG) Inc., www.ergpower.com.