Datasheet

AN4165 Efficiency
Doc ID 023661 Rev 1 17/37
8 Efficiency
Active mode efficiency is defined as the average of the efficiencies measured at 25%, 50%,
75% and 100% of maximum load, at nominal input voltage (V
IN
= 115 V
AC
and
V
IN
=230V
AC
).
External power supplies (the power supplies which are housed separately from the end-use
devices they are powering) need to comply with the Code of Conduct (version 4.0) "Active
mode efficiency" criterion, which requires an active mode efficiency higher than 77.7% for a
power throughput of 12 W.
Another standard to be applied to external power supplies in the coming years is the DOE
(Department of Energy) recommendation, whose active mode efficiency requirement for the
same power throughput is 82.96%.
The average efficiencies of the board at 115 V
AC
(83.33%) and at 230 V
AC
(81.34%) are
represented by dotted lines, and, along with the above limits, show that the STEVAL-
ISA111V1 demonstration board is compliant with both standards at 115 V
AC
and with the
Code of Conduct only at 230 V
AC
(refer to Figure 20 below).
In the same figure the efficiency at 25%, 50%, 75% and 100% of maximum load for both
input voltages is also shown.
Figure 20. Active mode efficiency of the demonstration board in comparison to
energy efficiency standards
AM13375v1
73
75
77
79
81
83
85
0.2 0.4 0.6 0.8 1
eff [%]
Iout [% I
OUT
]
115
230
av @ 115Vac
av @ 230Vac
DOE limit
CoC4 limit