Management by sharing

Power management involves more than heroic efforts to squeeze more battery life out of a feature-laden cell phone. Telecommunications switching centers, high-reliability servers and mainframe computers rely on some very sophisticated forms of voltage regulation and power management.

Contributors to this issue of Signals, manufacturers of power-management components, describe several methods of buffering the power supplies of a circuit card from other cards. Tom DeLurio and George Hall of Summit Microelectronics Inc. present an overview of the processes used to monitor and control on-board voltages and current rushes (the full text can be found at www.planetanalog.com).

Greg Sutterlin of Maxim Integrated Products Inc. describes the basic switch mechanisms-building blocks-that can be used to sequence power regulators in multivoltage systems (such as telecom line cards). Reno Rossetti of Fairchild Semiconductor International describes point-of-load voltage converters and explains how those for high-availability systems differ from those used on PC motherboards. Haachitaba Mweene and Don Ashley of National Semiconductor Corp. follow this theme with a description of some of the high-voltage options available for POLs, especially in telecom switching systems and basestations.

A trio of authors-Alan Moloney of Analog Devices Inc., Steve Hemmah of Texas Instruments Inc. and Suzanne Nee of ON Semiconductor-describe hot-swap circuitry, the mechanisms that use the current flow through a sense resistor to monitor and regulate the turn-on/ turn-off currents going through a circuit card as it is plugged in or pulled out of a card cage.

Finally, Justin Bennett and John Hu of Altera Corp. show how hot-swap switching concepts can be applied to programmable logic devices. The devices, the authors explain, have controlled current pathways that protect them from surges in hot-socketing applications-those that require the replacement of an FPGA-based system-on-chip device while its host board is powered and running.