Controllable high-power, variable-frequency CMOS circuit for microactuator applications

Abstract

A large-output power, high-current high-voltage, CMOS driving circuit for electrothermal microactuators is presented in this work. The circuit addresses the challenge of providing microelectromechanical systems devices with a monolithic integrated circuit that is capable of outputting high voltage with low output resistance that matches the actuator load for maximum power transfer. The circuit is implemented using a modified eight-stage charge pump. A digital control logic is designed to control the working charge pump stages in order have a variable output voltage between 4 and 15.5 V on a load producing about 150 mW maximum output power. To the authors’ knowledge, the circuit’s output resistance is the lowest among charge pumps that are capable of producing such high voltages. An AC pulse output of 15.5 V amplitude and variable frequency between 60 and 2000 Hz is included in the circuit. The circuit is operated by a conventional 5 V supply. With the variable DC output voltage level and AC output capability, the circuit is suitable for driving many electrothermal microactuators. The total size of the chip excluding pads is 5 mm2.