Evaluation of granularity on threshold voltage control in flex power FPGA

Abstract

Flex Power FPGA can flexibly control the operating speed and power consumption by flexible assignment of the threshold voltage to transistor. This paper evaluates the static power consumption and area overhead on various threshold voltage control granularity in the Flex Power FPGA based on specific settings. There is the trade-off relationship between static power and area overhead in threshold voltage control granularity in Flex Power FPGA with bulk MOS transistors. Moreover, division of the threshold voltage controlled transistor area has a big influence on the trade-off. For example of evaluation results, static power reduces less than 1/5 of original level, while increase an area overhead of less than 40% by appropriately dividing the threshold voltage controlled transistor areas. If an area increase of 50% is allowed, then the reduction in static power consumption to 1/10 or less is obtained.