A High Conversion Ratio Component-Efficient Charge Pump for Display Drivers

Abstract

In this paper, a scheme combining the advantages of both Dickson charge pump and Fibonacci charge pump has been proposed to output 30 V voltage for display driver integrated circuit applications. With only two external capacitors, it fits for small-sized package like smart card applications. The flying capacitors of Dickson charge pump were optimized and 2.3% of the chip size was saved. Meanwhile a highly precise and simple model for one-stage Fibonacci charge pump was utilized. By using RC charging theory, its voltage error can be limited within 0.02% and it is feasible for further efficiency optimization. Based on a 0.11 μm 1.5 V/6 V/32 V process, three different types of layouts for the built-in capacitors were fabricated to further optimize the chip size and their performance was compared. They enhance the flying capacitance by 6%, 26%, and 64%, respectively, compared with the traditional design. This design improves the maximum current drivability and the power efficiency is higher than 53%.