An 8-mW, 8-kB Cache Memory Using an Automatic-Power-Save Architecture for Low Power RISC Microprocessors

Yasuhisa SHIMAZAKI  Katsuhiro NORISUE  Koichiro ISHIBASHI  Hideo MAEJIMA  

Publication
IEICE TRANSACTIONS on Electronics   Vol.E79-C   No.12   pp.1693-1698
Publication Date: 1996/12/25
Online ISSN: 
DOI: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Low-Power LSI Technologies)
Category: 
Keyword: 
RISC microprocessor,  cache memory,  low power,  

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Summary: 
An embedded cache memory for low power RISC microprocessors is described. An automatic-power-save architecture (APSA) enables the cache memory to operate with high speed at high frequencies, and with low power dissipation at low frequencies. A pulsed word technique (PWT) and an isolated bit line technique (IBLT) reduce the power dissipation of the cache memory effectively. Using these three techniques, the power dissipation of the cache memory is reduced to almost 60% of the conventional cache memory at 60 MHz and to 20% at a clock frequency of 10 MHz. An 8 KByte test chip using 0.5 µm CMOS technology was fabricated, and it achieves 80 MHz operation at a supply voltage of 3.1 V, and 8 mW operation at a supply voltage of 2.5 V at 10 MHz.