June 10, 2011 -- High-performance servers have long used a power-measurement method that is based on analog-current sensing, filtering, and calibration circuits providing signals to an ADC contained in the Baseboard Management Controller (BMC). This system typically uses a calibration circuit to provide state of the art accuracy, although the shunt resistor itself is not included within the calibration loop. The component count and board real-estate requirements of this circuit are high.

Power density is not the only issue in today's data center; operating cost has been another hot topic as the number of servers rose in the past years. Many techniques such as power capping have been introduced to increase energy efficiency in data center, but the ability to measure the power level accurately remain the key factor. This article compares the area, cost, power saving, and other benefits gained with an integrated solution used in protection and power measurement in servers compared to discrete implementations.

By Joy Taylor and Jerry Steele. (Taylor is a product marketing manager at National Semiconductor Corp. and Steele is a strategic applications engineer at National Semiconductor's Tucson Design Center.)