Area-efficient CMOS charge pumps for LCD drivers

Area-efficient 4/spl times/ 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/spl times/ charge pump is then designed to deliver 100 /spl mu/A at 9 V using a 0.8-/spl mu/m AMS high-voltage CMOS process. The topology can be extended to 2n/spl times/ charge pumps, and a 6/spl times/ charge pump is also fabricated and tested to demonstrate the validity of the extension.