Design of a low power VLSI systems powered by ambient mechanical vibration

Abstract

Low power design trends raise the possibility of using ambient energy to power future digital systems. This thesis explores the design of such systems for collecting and processing data from sensors. The low throughput requirements of this type of computation allows aggressive scaling of supply voltages and enables very low power solutions. We discuss implementations of a generator for transducing mechanical vibration to electrical energy using macroscopic and MEMS technology. A DC/DC converter chip has been designed and tested to demonstrate the feasibility of operating a digital system from power generated by vibrations in its environment. A moving coil electromagnetic transducer was used as a power generator. A single generator excitation produced 23 ms of valid DSP operation at a 500 kHz clock frequency, corresponding to 11,700 cycles. An ultra low power DSP chip has also been designed that implements a power scalable detection and classification algorithm for a biomedical sensor. This chip demonstrates appropriate architectural and circuit techniques for low to medium throughput sensor applications. It consumes 550 n W at 1.5 V with a 1 kHz clock frequency.