This power supply was developed for an instrument manufacturer to provide very clean supplies for signal conditioning amplifiers with precision filters. The power supply has four synchronous buck converters. These provide ±15 volts at 2.5 amps on one printed circuit board and +5 volts at 2.5 amps with +5 volts at 1 amp on a second board. Output line noise was measured at less than 1mV rms and 5mV p-p.

The supply has a closed steel case to minimise radiated noise and fits inside a 3U rack. The limited width available meant that the layout had to be carefully designed so that tall components on one board did not coincide with the tall components on the other. The components dissipating most power were positioned to best utilise the air flow through the case and a fan could be added for running in more adverse ambient environments. The high current bridge rectifiers were mounted on the rear of the circuit boards and heat sinked directly to the case.

Mains power is taken in through an IEC plug on the rear panel and fed out through a 32-way DIN41462 connector on the main board to the custom backplane.

There are four voltage monitoring circuits, each driving bi-colour LEDs on the front panel. The 5 volt supplies are fitted with overvoltage clamping and crowbar circuits to protect the components in the power supply load.