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Design Guide & Applications Manual
For VI-200 and VI-J00 Family DC-DC Converters and Configurable Power Supplies
vicorpower.com 800-735-6200 Applications Engineering 1-800-927-9474 Rev. 2.1
Page 19 of 88
9. EMC Considerations
Common-Mode Noise with Common-Mode Choke.
There are no special precautions that must be exercised in
the design of input filters for Vicor converters. In fact, if
the system contains an EMC filter designed for typical
fixed frequency converters, it should be sufficient as is
(although not optimal in terms of size), as zero-current-
switching converters inherently generate significantly less
conducted noise.
The plots in Figure 9–2 are representative of fixed
frequency converters with input filtering.
NOTE: In most cases, a fixed frequency converter
generates more input conducted noise with a filter
than Vicor’s zero-current-switching converter without
a filter. Also note that fixed frequency converters
using a construction technique involving control
circuitry on the same metal plate as power processing
components will generate significantly more input
noise than shown.
+IN
–IN
+OUT
–OUT
C1 = 2.2 μF
C2 = 100 μF
C3 = Internal
C4 = Internal
L1 = 3 mH
Conditions:
Light Load = 3 A
Nominal Load = 15 A
Full Load = 30 A
C1
L1
C2
C3
C3
C4
C4
Nominal Line = 48 V
Figure 9–2 — Conducted input noise, typical fixed frequency converter with filter
3 Amp Load 15 Amp Load 30 Amp Load
Typical Fixed Frequency Converter (PWM)
48 V Input, 5 V Output
Conducted Noise vs. Load