A controller LSI for realizing V DD-hopping scheme with off-the-shelf processors and its application to MPEG4 system

Abstract

An LSI has been fabricated and measured to demonstrate feasibility of V DD-hopping scheme in an embedded system level by executing MPEG4 CODEC. In the V DD-hopping, supply voltage of a processor is dynamically controlled by a hardware-software cooperative mechanism depending on work-load of the processor. When the workload is about a half, the V DD-hopping is shown to reduce power to less than a quarter compared to the conventional fixed-V DD scheme. The power saving is achieved without degrading real-time features of MPEG4 CODEC.