MAX1611

19-1128; Rev 0; 9/96 KIT ATION EVALU E L B A AVAIL Digitally Controlled CCFL Backlight Power Supplies ____________________________Features _______________General Description The MAX1610/MAX1611 are fully integrated, highefficiency drivers for cold-cathode fluorescent lamps (CCFLs). They operate from a 4.5V to 26V power source. An on-board, high-switching-frequency power MOSFET reduces external component count and magnetics size. The MAX1610/MAX1611 protect against open or shorted lamps. The CCFL can be driven from an isolated transformer secondary winding to improve efficiency and avoid flicker at dim tube settings. Brightness is adjusted by scaling the lamp current, or by operating with a fixed lamp current and chopping the CCFL on and off at a rate faster than the eye can detect. The MAX1610’s digital inputs increment, decrement, or clear an internal, 5-bit up/down counter, which sets CCFL brightness. The MAX1611 uses a System Management Bus (SMBus) 2-wire serial interface to directly set CCFL brightness. Both devices include micropower shutdown and a linear regulator that eliminates the need for a separate logic supply. The digital interface remains active in shutdown, preserving the brightness setting. MAX1610/MAX1611 ® Direct Digital Control of CCFL Brightness ® Low Supply Current: 3mA Max Operating ® Low-Voltage Operation, Down to 4.5V ® Internal 26V, 0.7W Power Switch ® Protection Against Open or Shorted Lamps ® Supports Isolated Transformer Secondary ® SMBus Ser...