ML4877

NEW! L 30W CCF Inverter D esign JULY 2000 ML4877* LCD Desktop Backlight Lamp Driver GENERAL DESCRIPTION The ML4877 is an ideal solution for driving multiple cold cathode fluorescent tubes (CCFL) used in liquid crystal display (LCD) backlight applications. It provides dimming ballast control for the LCD display. By utilizing differential drive the ML4877 can deliver the same light output with significantly less input power compared to existing single ended drive schemes. Improvements as high as 30% can be realized when using low power lamps and advanced LCD screen housings. This increased light output is achieved because the differential drive configuration is much less sensitive, and therefore less power is wasted in the capacitive parasitics that exist in the backlight housing. An additional benefit of this configuration is an even distribution of light. The IC includes an adjustable lamp out detect circuit that latches the IC off when a lamp fault is detected. Also, the unique architecture of the ML4877 allows the development of a backlight system that will inherently meet the UL requirements for safety. The ML4877 is optimized for large LCD applications applications where high efficiency is critical to maximize battery life. The high efficiency is achieved by a resonant scheme with zero voltage switching. FEATURES s s s s s s s s s Ideal for 30W inverter designs, 1 to 8 lamp design PWM dimming capability Backlight lamp driver with differential drive Up to 30% lower po...