Establish Circuit Requirements

DESIGN PHASE:       preliminary design
SUB ELEMENT NAME:   establish circuit requirements
APPLICABILITY:      all circuits

ACTIVITY:  Review baseline design requirements in proposal and
contractual documents and validate/update based on discussions
with lead engineer, responsible system engineers, and engineers
working on interfacing circuits.  Extend requirements and add
design margins as necessary to define circuit that will be

OUTPUT:  Report, Subject: Design Requirements, XXX
Circuit, with advanced copy available at conceptual design
review.  This report shall be issued or counter signed by the
responsible system engineer and updated as changes occur to
accurately reflect requirements throughout the design cycle.
Traceability to specified and derived requirements (and how
derived) will be made explicit.  (For example, requirement from
system engineer may be 5V +/-5%, at 6.8A.  Circuit requirement
may be 5V +/- 3% at 8A to allow for design margin, growth, etc.)
Letter will eventually be replaced by a requirements section in
the final report.


[HEPECR] =               engineer hours to establish requirements
0.0+                     set up time
0.1*                     time per part
[PARTS COUNT]+           circuit parts count
0.0*(                    time per input/output
[INPUT COUNT]            number of inputs
+[OUTPUT COUNT])         number of outputs


Author: Jerrold Foutz,

Original: Foutz, J., Power Supply Circuit Development Estimating Aid - An Expert System Application, IEEE Applied Power Electronics Conference Record, New Orleans, February 1-5, 1988. Revised 28 February 2001