Design Article
Moving from CCFT- to LED-backlit LCD modules
Todd Stonewall and Eric Bleak, Sharp Microelectronics of the Americas
2/5/2013 5:54 AM EST
External drive circuitry
When comparing a CCFT inverter to an LED driver, there are a number of positives for the LED driver - no need for the precautions required by high voltage, less power used, and similar form-factors are available from most suppliers for inverter boards and LED driver boards.
In cases where all other things are equal (except the backlight), changing the LCD module type can be as simple as removing the CCFT-backlit unit, removing the inverter, replacing the inverter board with an LED driver board from the same manufacturer, hooking up the new LED-backlit unit, and replacing it. Sharp has a video online that shows how simple this process can be. Todd Stonewall demonstrates how easily the change can be made.
For a drop-in driver solution, Endicott Research Group (ERG) has the Smart Force Drop-in Replacement Series of LED drivers that have the same footprint and input voltages as their CCFT-driver counterparts.
When using a PWM for dimming, many available LED driver boards offer plug-and-play replacements, with PWM inputs as well as analog inputs for dimming. Generally, LED backlights are made to be compatible with existing PWM and DC dimming schemes. A number of manufacturers offer outboard LED drivers that utilize common dimming input methods for their driver boards.
When contemplating an overall redesign from scratch, mSilica (now owned by Atmel) markets a line of controller chips that only require a few external components to form a complete LED backlight driver.
When comparing a CCFT inverter to an LED driver, there are a number of positives for the LED driver - no need for the precautions required by high voltage, less power used, and similar form-factors are available from most suppliers for inverter boards and LED driver boards.
In cases where all other things are equal (except the backlight), changing the LCD module type can be as simple as removing the CCFT-backlit unit, removing the inverter, replacing the inverter board with an LED driver board from the same manufacturer, hooking up the new LED-backlit unit, and replacing it. Sharp has a video online that shows how simple this process can be. Todd Stonewall demonstrates how easily the change can be made.
For a drop-in driver solution, Endicott Research Group (ERG) has the Smart Force Drop-in Replacement Series of LED drivers that have the same footprint and input voltages as their CCFT-driver counterparts.
When using a PWM for dimming, many available LED driver boards offer plug-and-play replacements, with PWM inputs as well as analog inputs for dimming. Generally, LED backlights are made to be compatible with existing PWM and DC dimming schemes. A number of manufacturers offer outboard LED drivers that utilize common dimming input methods for their driver boards.
When contemplating an overall redesign from scratch, mSilica (now owned by Atmel) markets a line of controller chips that only require a few external components to form a complete LED backlight driver.
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anne-francoise.pele
4/12/2013 8:54 AM EDT
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