Special Bulletin: K Class Power System

The power system in the HP 9000 K-class servers uses a number of new and emerging technologies to achieve excellent platform performance without compromising cost, reliability, and quality metrics. Combined in the power system are the system power monitor, the system power supply, and an optional uninterruptible power supply (UPS). Key contributions of the system power monitor include: system turn-on and initialization including error reporting via a front-panel LCD display, temperature monitoring and cooling, fan speed control based on ambient temperature, fan synchronization and fault detection, continuous power supply output voltage monitoring, special manufacturing modes of operation, overtemperature detection and warning, overtemperature shutdown, and other features. The system power supply uses power factor correction to achieve low power-line distortion while maximizing the available VA capacity of the input ac circuit. A standard dc-to-dc forward converter follows the regulated power factor corrected output. Remote sensing is used on all output rails to achieve tight regulation specifications. The power system is optimized for use with several HP UPSs employing both offline and online technologies. The UPSs use an autoranging technology allowing worldwide use. Worldwide regulatory and safety approvals apply to these UPSs. The hardware provides power-line filtering and conditioning while the firmware provides many useful status and control capabilities, both real-time and programmed for later execution.

by Gerald J. Nelson, James K. Koch