A 16-bit Digital Signal Processor with Specially Arranged Multiply-Accumulator for Low Power Consumption

Katsuhiko UEDA  Toshio SUGIMURA  Toshihiro ISHIKAWA  Minoru OKAMOTO  Mikio SAKAKIHARA  Shinichi MARUI  

IEICE TRANSACTIONS on Electronics   Vol.E78-C   No.12   pp.1709-1716
Publication Date: 1995/12/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Low-power Analog, Digital LSIs and ASICs for Multimedia)
integrated electronics,  digital signal processor,  low power consumption,  communication,  

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This paper describes a new, low power 16-bit Digital Signal Processor (DSP). The DSP has a double-speed MAC mechanism, an accelerator for Viterbi decoding, and a block floating section which contribute to lower power consumption. The double-speed MAC can perform two multiply and accumulate operations in one instruction cycle. Since MAC operations are so common in digital signal processing, this mechanism can reduce the average clock frequency of the DSP resulting in lower power consumption. The Viterbi accelerator and block floating circuitry also reduce the clock frequency by minimizing the number of required cycles needed to be executed. The DSP was fabricated using a 0.8 µm CMOS 2-aluminum layer process technology to integrate 644 K transistors on a 9.30 mm9.09 mm die. It can realize an 11.2 kbps VSELP speech CODEC while consuming only 70 mW at 3.5 V Vdd.