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1.3

Switch-mode power supplies, DC/DC converters

Inductive components are used for magnetic energy storage in all kinds of switch-mode power sup-

plies and DC/DC converters. For example, the SIMID 1812 product range is used in low-power step-

up converters in automobile electronics and in battery-powered equipment. They can be subjected

for short periods to currents which are the quadruple of their current rating without any saturation

effects occurring.

1.4

EMC applications

For broadband interference suppression, current-compensated chokes with ring cores or D cores

and powder core chokes are especially suitable.

Apart from use as filters in mains and other power supply lines, such chokes are important for data

lines as used in telecommunications engineering, e. g. in NTBAs (Network Termination Basic Ac-

cess Units, ISDN), in line cards in telephone exchanges (ISDN and analog) and in the fast-expand-

ing CAN bus application field (CAN = Controller Area Network) in automotive electronics.

Almost all the component families are approved in accordance with the main international stan-

dards. All chokes for low-frequency mains networks are dimensioned and tested in compliance with

the applicable EN and IEC standards.

Inductive components with particularly good RF characteristics are achieved by the use of ungapped

cores. The manufacturing methods developed by EPCOS lead to good reproducibility of the attenua-

tion characteristics and enable the production of high-quality components at a favorable price.

The company’s many years of experience guarantee that customers quickly and economically ob-

tain just the right solutions to their EMC problems. Our own EMC laboratory in Regensburg or one

of our European EMC partner laboratories is at your disposal at all times to help with professional

advice and in carrying out measurements (also refer to the chapter on “Services”).

1.4.1

Propagation of interference

Interference voltages and currents can be grouped into common-mode interference, differential-

mode interference and unsymmetrical interference:

s

Common-mode interference (asymmetrical interference):

– occurs between all lines in a cable and reference potential (fig. 1a),

– occurs mainly at high frequencies (from approximately 1 MHz upwards).

s

Differential-mode interference (symmetrical interference):

– occurs between two lines (L-L, L-N) (fig. 1b),

– occurs mainly at low frequencies (up to several hundred kHz).

SSB1465-P

asymmetrische

Ausbreitung

symmetrische

Ausbreitung

unsymmetrische

Ausbreitung

as

U

s

U

us1

U

us2

U

1a

1b

1c

Fig. 1

Propagation modes

asymmetrical

propagation

symmetrical

propagation

unsymmetrical

propagation

SSB1465-P

U = V = voltage

General Technical Information