A low power controller for a MEMS based energy converter

Abstract

The trend in modern VLSI design towards low power DSP and sensing applications creates an opportunity for the development of self-powered systems based on harvesting ambient energy. Several different ambient sources have already been exploited. With advances in microelectromechanical (MEMS) technology, it is possible to implement a self powered system-on-a-chip with the MEMS device acting as the energy transducer in the form of a variable capacitor, with conversion controlled by employing low power digital control techniques. This thesis explores the design of such an energy converter. The theory behind the conversion process will be discussed, including the presentation of a mathematical model for the system. The design of a programmable delay line based digital controller and optimization of the accompanying complementary power switches is reviewed. Results from the fabricated controller are presented and discussed. The design of a self-locking controller, which is based on the present architecture, but uses a new energy feedback technique to phase lock to maximal energy transfer, is presented.