EMC VI-200 Bedienungsanleitung PDF herunterladen

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 18 of 88

+IN

GATE

OUT

–IN

+OUT

TRIM

–S

–OUT

C1 = 100 μF

C2 = 4,700 pF

C3 = 0.01 μF

Conditions:

Light Load = 3 A

Nominal Line = 48 V Nominal Load = 15 A

Full Load = 30 A

Figure 9–1 — Conducted input noise, no additional filtering

3 Amp Load 15 Amp Load 30 Amp Load

CONDUCTED NOISE

Conducted noise is the AC current flowing between the

source voltage and the power supply. It includes both

common-mode and differential-mode noise. Vicor zero-

current-switching converters are 20 – 40 dB lower in

conducted noise than a traditional board-mounted PWM

converter; however, if a specific EMC specification such as

FCC or VDE must be met, additional filtering may be required.

Since the noise generated is ten to a hundred times lower

than fixed frequency converters, an existing filter should

provide equal or better performance when the conditions

in the

Module Do’s and Don’ts section are followed.

(Section 3)

In the event the system does not contain an existing filter,

the following will provide valuable information relative to

the attainment of system conducted noise objectives.

System requirements, such as Tempest (military) or UL544 /

EN60601 (medical), require a somewhat different approach.

Medical requirements vary as a function of the application

and country — please contact Vicor Applications

Engineering for additional details.

Common-Mode Noise with No Additional Filtering.

Common mode conducted noise current is the

unidirectional (in phase) component in both the +IN and

–IN pins to the module. This current circulates from the

converter via the power input leads to the DC source and

returns to the converter via the grounded baseplate or

output lead connections. This represents a potentially

large loop cross-sectional area which, if not effectively

controlled, can generate magnetic fields. Common-mode

noise is a function of the dv/dt across the main switch in

the converter and the effective input to baseplate and

input to output capacitance of the converter.

The most effective means to reduce common-mode current

is to bypass both input leads to the baseplate with

Y-capacitors (C2), keeping the leads short to reduce

parasitic inductance. Additionally, a common-mode choke

(L1) is usually required to meet FCC/ VDE A or B. (Figure

9–2)

9. EMC Considerations

Conducted Noise vs. Load

Typical Vicor Module

48 V Input, 5 V Output (VI-230-CV)

1 2 3 4 5 6 ... 10 11

9. EMC Considerations 1