The 34844 is a high efficiency, LED driver for use in backlighting LCD displays from 10" to 20"+. Operating from supplies of 7V to 28V, the 34844 is capable of driving up to 160 LEDs in 10 parallel strings. Current in the 10 strings is matched to within 2%, and can be programmed via the I2C/SM-Bus interface. The 34844 also includes a Pulse Width Monitor (PWM) generator for LED dimming. The LEDs can be dimmed to one of 256 levels, programmed through the I2C/SM-Bus interface. Up to 65,000:1 (256:1 PWM, 256:1 Current DAC) dimming ratio. The integrated boost converter generates the minimum output voltage required to keep all LEDs illuminated with the selected current, providing the highest efficiency possible. The integrated boost selfclocks at a default frequency of 600kHz, but may be programmed via I2C to 150/300/600/1200 kHz. The PWM frequency can be set from 100Hz to 25kHz, or can be synchronized to an external input. If not synchronized to another source, the internal PWM rate outputs on the CK pin. This enables multiple devices to be synchronized together. The 34844 also supports optical/temperature closed loop operation and also features LED over-temperature protection, LED short protection, and LED open circuit protection. The IC also includes overvoltage protection, over-current protection, and under-voltage lockout.