EMC VI-200, VI-J00 EMC Considerations, Typical Fixed Frequency Converter PWM Input, 5 V Output

Design Guide & Applications Manual 9. EMC Considerations

For VI-200 and VI-J00 Family DC-DC Converters and Configurable Power Supplies

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.

Typical Fixed Frequency Converter (PWM)

48 V Input, 5 V Output

L1

C1 C2

C3 C4

+IN–OUT

–IN

+OUT

C3 C4

		Conditions:
C1	= 2.2 μF	Light Load = 3 A
C2	= 100 μF Nominal Line = 48 V	Nominal Load = 15 A
C3	= Internal	Full Load = 30 A
C4	= Internal

L1 = 3 mH

3 Amp Load

Conducted Noise vs. Load

15 Amp Load 30 Amp Load

Figure 9–2— Conducted input noise, typical fixed frequency converter with filter

vicorpower.com 800-735-6200 Applications Engineering 1-800-927-9474 Rev. 2.1

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