Power Supply Circuit Design
Subelement Task Descriptions

Detailed work plans for the circuit design of power supplies are provided that can be modified and expanded to aid in estimating the cost of power supply design.


These work plans for estimating power supply circuit design are updated versions described in Power Supply Circuit Development Estimating Aid - An Expert System Application, which can be referred to for additional information. The work plans can be modified, deleted, or others added as necessary to reflect any design environment.

These work-plan subelements can be used several ways. One is as a tutorial to teach what is involved in power supply circuit design. Another is to add the algorithms that describe your way of doing circuit design and then make them part of an expert system or spreadsheet that you can use to estimate circuit design. Computer tools are not necessary. For each design, a set of sub-elements can be printed and placed in a notebook with the hand calculated algorithms for each work plan. The total of the sub-elements gives an estimate for the complete circuit design cost. However used, they should be calibrated against actual costs so that they gain in usefulness and credibility over time.

The plans do not include circuit board layout, prototype fabrication, assembly, and test, etc., but can be expanded to include these. The referenced paper gives more information.

The author has noted that many engineers design circuits like a hobbyist or a student completing a homework assignment. This simplified approach usually results high field failure rates because the designer did not do a worse case design or sufficient lab testing. It is hoped that these work-plan subelements give some insight in how circuits are designed to give high field reliability.

The term report is used for documenting the results. This can be a memo, internal letter, or what ever document that will be recoverable throughout the life cycle of the design. One documentation method is an Intranet based project file, which will be a future topic on this website.

Preliminary Design

[HEPOLLTP]     order long lead time parts 
[HEPSCHED]     schedule
[HEPECR]       establish circuit requirements
[HEPVCC]       verify circuit concept
[HEPVCA]       verify circuit apportionment
[HEPCDR]       concept design review

Paper Design

[HECCCV]       calculate component values
[HECSTAB]      stabilize feedback loop
[HECMAG]       specify magnetics
[HM]           magnetic work authorization


[HEB]          breadboard instructions
[HTB]          breadboard fabrication


[HEMP]         point measurements
[HEMR]         regulation measurements (plots)
[HEMSTAB]      stability measurements
[HEMX]         transfer function measurements
[HEMSPEC]      spectrum measurements
[HEMPHOTO]     photo measurements
[HEMFAIL]      failure modes                       
[HEMTHERM]     thermal measurements                  
[HEMOVEN]      environmental measurements             
[HTMPHY]       physical measurements
[HEMMAG]       magnetic measurements
[HEMTFSOA]     forward biased secondary breakdown measurement
[HEMTRSOA]     reverse biased secondary breakdown measurement
[HEMTL]        line, load, and reference transient measurement
[HEMTSLOS]     switching losss measurements
[HEMTSNUB]     snubber waveform measurements
[HEMTSHTH]     shoot-through measurements
[HEMTCAP]      capacitor ac current measurements


[HEASC]        schematic capture
[HEANOM]       nominal dc analysis
[HEASEN]       sensitivity analysis
[HEAPS]        power supply sequencing
[HEAWC]        worst case analysis
[HEACFS]       circuit failure simulation
[HEAR]         regulation analysis
[HEASTAB]      stability analysis
[HEAMC]        middlebrook criteria
[HEAX]         transfer function analysis
[HEACAP]       capacitor ac current
[HEAS]         spectrum analysis
[HEATL]        line and load transient analysis
[HEATIN]       inrush current analysis
[HEATHUT]      hold up time analysis
[HEATSC]       short circuit recovery analysis
[HEATOS]       overshoot analysis
[HEAT]         thermal analysis
[HEAP]         physical calculations
[HEATSC]       transient component stress analysis

Add reliability analysis
Add Failure Modes and Effects analysis
Add Sneak Path analysis


[HER]          reconcile   


[HED]          document   

Add design reviews


[HESLAY]       layout support                       
[HESO]         other support

Author: Jerrold Foutz, foutz@smpstech.com

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 27 February 2001