Stability Measurements

DESIGN PHASE:       measurement
SUB ELEMENT NAME:   stability measurement
VARIABLE NAME:      [HEMSTAB]
DATE:               REVISION LETTER:     REVISION DATE: 
APPLICABILITY:      feedback circuits

ACTIVITY:  Measure and plot open loop and closed loop gain/phase.
Specialized equipment usually necessary (Venable, Ridley, etc).

OUTPUT:  Measurements and plots in laboratory notebook for
comparison to specifications and analysis.

ALGORITHM:

[HEMSTAB] =              engineer hours for stability measurements
[HTMSTAB] =              technician hours for stability measurements
0.0+                     set up time
0.0*                     hours per feedback loop
[FEEDBACK LOOP COUNT]*   number of feedback loops
([NWC]+                  number of worse case measurement sets = 4
1)                       nominal condition measurement

DISCUSSION:

Worse case conditions for stability are usually:

Minimum line, maximum load
Minimum Line, minimum load
Maximum Line, maximum load
Maximum Line, minimum load

Measurements are also usually taken at nominal conditions.

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 21 February 2001