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Power-Efficient Embedded Processing

Liu Yijun


As more and more transistors and functionality are integrated in single chips, power consumption has become one of the most important design parameters in modern embedded circuits. The purpose of the work described in this dissertation is to identify ways to reduce the power consumption of embedded systems. Low-power design is a complex task requiring care at all levels of the design hierarchy. In this dissertation, the focus is mainly on the following low-power techniques: Exploring asynchronous logic design for its low-power potential. The power-efficiencies of asynchronous and synchronous designs are compared. Different asynchronous design issues are also discussed in terms of their power-efficiency. Circuit-level optimizations to reduce the power consumption of function units, including adders and multipliers, and memory. An asynchronous carry-lookahead adder and a pipelined iterative multiplier are presented, both of which are designed based on analyses of their input data characteristics. The circuit-level design issues of a low-power embedded SRAM macro are also presented. Architecture-level optimizations to reduce the execution overheads of soft-programmable processors. A hierarchical processing architecture is proposed based on an analysis of embedded processing programs. A RISC-like coprocessor has been designed to demonstrate the power-efficiency of a hierarchical processing architecture. A dataflow coprocessor has also been designed which is more power-efficient and faster than the RISC-like coprocessor. Together these results demonstrate that there is scope for improvements in power-efficiency at several different levels in the design hierarchy, underlining the need to treat low-power design as a holistic process.

The thesis is available as PDF (2.0MB).