The AT1309 step-up converter is designed for small or medium size LCD panel of high bias voltage with a constant current to provide PDAs, and other hand-held devices. It features a fast 1.4 MHz current-mode PWM control with a built-in 0.3 N-MOS that allows for smaller capacitor and inductor. Fault condition protection uses cycle-by -cycle current limiting to sense maximum inductor current and thermal protection. Also included soft-start eliminates inrush current during start-up.