A 0.13- μ m CMOS Dynamically Reconfigurable Charge Pump for Electrostatic MEMS Actuation

An eight-stage reconfigurable charge pump for microelectromechanical system (MEMS) electrostatic actuation was designed and fabricated in a standard 0.13-μm CMOS technology. The purpose of the circuit is to generate sufficient on-chip voltages that are continually reconfigurable for MEMS actuation. Small 1-pF pumping capacitors are used to reduce the circuit area. Digitally programmable voltage levels can be out putted by varying the number of stages and the clock drive levels dynamically. Reduced power consumption is achieved using a variable frequency clock. The circuit attains a measured maximum output voltage of 10.1 V from a 1.2 V supply. Its nominal clock is set to 50 MHz. The circuit has a compact area of 215 μm × 300 μm and consumes 864 μW at a 50-MHz clock and 252 μW at an 8-MHz clock.