Design of a charge injection compensation system for MEMS electrostatic actuators

Abstract

The main goal of this project is to implement and experimentally verify various control algorithms for MEMS electrostatic actuators. Those algorithms include a charge injection compensation subsystem. The hardware platform consists of some MEMS electrostatic actuators, a front-end sensing system (comprising a full-custom mixed-signal integrated circuit designed at UPC and a highspeed A/D converter) and a Xilinx FPGA for algorithm coding. The work involves the following: o Understanding the working principle of the hardware platform and the issues related to MEMS electrostatic actuators. o Improve the hardware platform, if required by the control algorithm. This might involve some simple PCB design and test with laboratory instrumentation. o Algorithm implementation in VHDL. This includes the signal-processing algorithms and also the ancillary routines for I/O data extraction and signal visualization. Capacitance of MEMS electrostatic actuators were measured under different voltages conditions. It was found that positive voltage stress caused negative charging of the dielectric whereas negative voltage stress caused positive charging of the dielectric. This is consistent with the nature of traps in the silicon oxynitride dielectric used for the switches. Report is divided into three parts, the first chapter is devoted to the description to the MEMS word. The chapter is devoted a small multiplexing board design description. And finally chapter 3 introduce a development of a VHDL code to control all system.