Design of a dual‐input SC DC–DC converter realizing negative outputs

Abstract

AbstractAimed at a back‐lighting application, a dual‐input switched‐capacitor (SC) DC–DC converter with battery charge process is proposed in this paper. The proposed converter can realize −1/N× (N = 2,3,…) step‐down conversion as well as (N + 1)/N× step‐up conversion. By converting clean energy such as solar energy, the proposed dual‐input converter not only drives light‐emitting diodes (LEDs) but also recharges the battery, although conventional single‐input converter only consumes battery energy. In the proposed converter, the −1/N× stepped‐down voltage is generated to drive the LED's cathode when the input voltage is insufficient to drive a 1× transfer mode. Furthermore, unlike conventional converters, the battery is charged by the (N + 1)/N× stepped‐up voltage when the LED back light is in standby mode. Hence, the proposed converter can realize long battery run time. The validity of circuit design is confirmed by theoretical analyses, simulations, and experiments. The derived theoretical formulas will be helpful to estimate circuit characteristics, because the theoretical results correspond well with the simulation program with integrated circuit emphasis (SPICE) simulation results. © 2011 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.