Architectural trade-offs in the design of low power FIR filtering cores

There is a continuous drive for methodologies and approaches of low power design. This is mainly driven by the surge in portable computing. On the other hand, the design of low power systems for different portable applications is not a simple task. This is because of the number of constraints that influence the power consumption of a device. In addition to issues of performance and functionality, there is a need to satisfy strict test coverage constraints. The authors investigate the impact of DSP architectural realisation, multiplier type, and the choice of number representation on the overall power consumption of DSP devices. Work in the literature so far has concentrated on the effect of these on a part or a section of a DSP system. Furthermore the effect of DfT circuits on the overall performance is studied. A hearing aid device is considered as an example of a system with strict power/area constraints. It is shown that the choice of multiplier architecture and number representation should be carefully considered when specific DSP architectural choices are made. The results are demonstrated with a number of specially designed DSP architectures for the implementation of FIR filtering algorithms on hearing aid devices.