Vibration-to-electric energy conversion

A system is proposed to convert ambient mechanical vibration into electrical energy for use in powering autonomous low power electronic systems. The energy is transduced through the use of a variable capacitor. Using microelectromechanical systems (MEMS) technology, such a device has been designed for the system. A low-power controller IC has been fabricated in a 0.6-/spl mu/m CMOS process and has been tested and measured for losses. Based on the tests, the system is expected to produce 8 /spl mu/W of usable power. In addition to the fabricated programmable controller, an ultra low-power delay locked loop (DLL)-based system capable of autonomously achieving a steady-state lock to the vibration frequency is described.