A Hybrid Radix-4/Radix-8 Low Power Signed Multiplier Architecture

A hybrid radix-4/radix-8 architecture targeted for high bit, general purpose, digital multipliers is presented as a compromise between the high speed of a radix-4 multiplier architecture and the low power dissipation of a radix-8 multiplier architecture. In this hybrid radix4/radix-8 multiplier architecture, the performance bottleneck of a radix-8 multiplier, the generation of three times the multiplicand for use in generating the radix-8 partial product, is performed in parallel with the reduction of the radix-4 partial products rather than serially, as in a radix-8 multiplier. This hybrid radix-4/radix-8 multiplier architecture requires 13% less power for a 64 64-b multiplier, and results in only a 9% increase in delay, as compared with a radix-4 implementation. When the voltage supply is scaled to equalize delay, the 64 64b hybrid multiplier dissipates less power than either the radix-4 or radix-8 multipliers. The hybrid radix-4/radix-8 architecture is therefore appropriate for those applications that must dissipate minimal power while operating at high speeds.