Power Supply Conditioning Boards

The DNA-PC-921-D is a power supply conditioning module designed for use in UEI’s popular Cubes*. It has been designed to meet the surge and drop out requirements of MIL-STD-704 and 1275.

Internal brown-out/drop out energy is stored in a bank of 5 capacitors totalling 6000 μF charged to 38 VDC. Hold-up time can be determined by adding the total Cube power dissipation (Cube and I/O boards), adding 2.5 W for the PC-921-D and referring to the chart later in the datasheet. A Power Failed input can be read, allowing the system software to close any open SD card/FLASH files prior to CPU power loss. The Power Failed input can also be used to launch emergency shutdown actions.

Diagnostics on the DNA-PC-921-D power include the ability to monitor input current, input voltage and holding capacitor voltage (38 VDC at full charge.) Two diagnostic LEDs are also provided, one indicates the capacitors are either charged, or charging. The second indicates normal operating status of the board.

All connections are through a 37-pin D female connector mounted in the bottom two slots of the Cube. Users of the DNA-PC-921-D should not use the standard Molex power connector near the top of the Cube. No damage will occur if both the Molex connector and the PC-921-D are powered at the same time but this connection will eliminate the protection offered by the PC-921-D.

The DNA-PC-921-D does not require any software to function, though an easy to use API does provide the user access to the various diagnostics available. Included in these diagnostics are the ability to read the board’s input voltage (externally provided), the capacitor hold voltage (typically 38 VDC) as well as the internal 3.3 V power supply. Digital inputs are provided to indicate Power Failure, hold capacitor fully charged, and hold capacitor discharged. These diagnostics are available to all PowerDNA and UEIPAC. They may be added to other Cube deployments in the future. Please contact UEI for details.

*UEINet not included.