Liquid Crystal Display (LCD) Supplied by Highly Integrated Dual-Side Dual-Output Switched-Capacitor DC-DC Converter With Only Two Flying Capacitors

Abstract

This paper proposes a highly integrated dual-side dual-output (DSDO) switched-capacitor (SC) converter with only two flying capacitors. Generally, a dual-phase voltage doubler and an inverter are used to supply positive and negative voltages for thin film transistor-liquid crystal display (TFT-LCD) gate drivers, respectively. Four flying capacitors, eight pin-outs for the four flying capacitors, and 16 power switches are necessary for their operations in the driver integrated chip (IC). The proposed DSDO SC converter combines both dual-phase voltage doubler and inverter converter in one channel through the use of time multiplexing technique with minimal performance degradation. As a result, the proposed converter not only reduces the number of flying capacitors from four to two, but also removes four IC pin-outs for lower cost and more compact size. Moreover, the 16 required power switches are reduced to 12, resulting in an approximated 27% decrease of the silicon area.