Datasheet

AN4164 Testing the board
Doc ID 023660 Rev 1 15/38
Table 5 shows the measured value of the burst mode frequency ripple measured in different
operating conditions. The ripple in burst mode operation is very low.
5.4 Efficiency
The 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
=
230 V
AC
).
External power supplies (the power supplies are contained in a separate housing from the
end-use devices they are powering) need to comply with the Code of Conduct (version 4.0)
“active mode efficiency” criterion, which states an active mode efficiency higher than
71.18% for a power throughput of 4.2 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 76.6%.
If the IC is externally biased, the presented demonstration board is compliant with both
standards, as can be seen from
Figure 21 , where the average efficiencies of the board at
115 V
AC
(81.6%) and at 230 V
AC
(77.2%) are plotted with dotted lines, together with the
above limits. In the same figure the efficiency at 25%, 50%, 75% and 100% of output load
for both input voltages is also shown.
Figure 21. Active mode efficiency of the demonstration board and comparison with
energy efficiency standards (IC externally biased)
Table 5. Output voltage ripple at no/light load
V
IN
[V
AC
]
V
OUT
[mV]
No load 25 mA load
90 2 7
115 2 7
230 4 8
265 4 9
AM13342v1
65
67
69
71
73
75
77
79
81
83
85
0.2 0.4 0.6 0.8 1
eff [%]
Iout [% I
OUT
]
115
230
av @ 115 Vac
av @ 230 Vac
DOE limit
CoC4 limit