This paper presents an analysis and design of a unidirectional resonant switched capacitor (URSC) step-up converter for OLED lamp driving. The URSC converter includes a very small inductor in series with the switched capacitor to improve the switching behavior. Also, the URSC converter presents the advantages of high power density, higher efficiency compared to other SC converters, low output voltage and current ripples and low EMI noise, which make it adequate for driving OLED lamps. URSC is designed to operate in closed loop with constant current VI control technique. By working the resonant inductor as a VI, the OLED current can be regulated and dimmed because of resonant frequency change. Simulation and experimental results of the VI inductor, which are in a good agreement, and the results of a URSC step-up converter design example for a 21.8 W OLED lamps array supplied from 48Vdc are presented, where a maximum 91.5% efficiency is obtained.