Area-efficient CMOS charge pumps for LCD drivers

Area-efficient 4× charge pumps based on the cross-coupled structure that uses the V/sub dd/-2V/sub dd/ outputs alternately to reduce the number of power devices and capacitors are presented. Compared with conventional designs, our best design can save two power transistors, one capacitor, and two level shift circuits. An integrated 4× charge pump is then designed to deliver 100 μA at 9 V using a 0.8-μm AMS high-voltage CMOS process. The topology can be extended to 2n× charge pumps, and a 6× charge pump is also fabricated and tested to demonstrate the validity of the extension.