This template was developed to assist the power supply designer, systems
engineer, or program manager to predict the relative packaging density of a
military power supply as a function of the following factors:
- Power output
- Number of outputs
- Level and type of input power
- Hold-up time
- EMI requirements
- Auxiliary functions (BITE, inhibit, etc.).
The worksheet must be used in conjunction with the "Low Voltage Power
Density Curves" (see Figure D-1) which depict four areas of relative
complexity (density) with the X AXIS being the number of outputs and the
"Power Density Index" on the Y AXIS.
The spreadsheet does not claim that densely packaged power supplies are
unreliable or impossible to design and manufacture; rather, the point is made
that as the relative density increases (as in Regions 3 and 4), the development
schedule and development costs increase, the maintainability decreases and the
ability to keep junction temperatures low becomes more difficult. There are two
functions that the spreadsheet can accomplish. They are:
(1) Determine the relative complexity of a power supply
(2) Determine the volume required for the power supply given the number of
outputs and their characteristics and as a function of the relative packaging
density required by a system.
The spreadsheet is iterative in nature and "what if" changes can easily be
made to show the user or designer the results of tradeoffs in power supply
characteristics or volume.
A cell-by-cell listing is supplied for manual entry and future
The spreadsheet can be used on any IBM PC or compatible computer, and loads
with Lotus 1-2-3 (Reg Trademark) type spreadsheet software.
All of the cells of the worksheet that prompt the user should be protected
from accidental erasure or overwrite and only those cells that require user
entry are unprotected and are indicated by a " " symbol, (as well as a "U" in
the cell entry).
Lotus is a registered trademark of Lotus Development Corporation. Lotus
Development Corporation 1986. Used with permission.