A multi-level multi-phase charge-recycling method for low-power AMLCD column drivers

Abstract

This paper describes a new low-power design concept appropriate for column drivers of high-resolution active matrix liquid crystal displays with a dot inversion method. The proposed multi-level multiphase charge-recycling method reduces power consumption incurred in driving highly capacitive column lines by storing the charge into the external capacitors and reusing it in the next cycle. With the proposed method, power consumption can be reduced asymptotically to zero with the infinite number of storage capacitors. However it is also shown that total power reduction can be counterbalanced by the power consumption in driving switches used in the recycling process. Analytical equations, simulation results, and measurement results from an experimental chip are shown to validate the proposed method. Dynamic power reduction of 55%-70% is measured with a three-level five-phase charge-recycling method compared with a conventional column driver.