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What is Planar Technology? |
EXPERT TECHNICAL REPORT
Highly efficient - yet compact - power conversion is fundamental to continued profitable
growth of the telecommunications and data processing industries and of many others. Power
conversion sub-systems furnish electrical energy in a form needed by these end-use
equipments - 50volts DC for telecommunications, 5volts DC or 3volts DC for computers - are
but typical examples.
For safety reasons, transformers must invariably be incorporated, to galvanically isolate the
end equipments from the 230volts or 117volts, 50 or 60 Hz AC mains, as well as to adapt the
output voltage to the proper level. In such units, size is directly related to switching frequency,
higher frequencies translating into smaller volume, and also into higher efficiency, if the
right transformer design is chosen.
In the past, operating frequencies much above 20kHz were precluded by the non-availability
of suitable switching transistors. Now, with power MOSFETs (Metal-Oxide Semiconductor Field-Effect
Transistor) capable of converting power at frequencies well above 200kHz, the major obstacles
to ongoing performance improvements in power supplies are the limitations inherent in
conventional "wire-wound-on-a-bobbin" transformers and companion inductors.
Transformers made of the planar principle eliminate virtually all the shortcomings of
old-fashioned wire wound types. In a planar design, the windings are made so of copper
foil lead frames or printed circuit boards. (a flat copper spirals laminated into thin dielectric
substrates). These windings are then sandwiched, along with appropriate insulators, between large
area, yet thin, state-of-the-art ferrite cores. This construction technique yields a host of
benefits :
 Typical efficiency 98%
Low leakage inductance, typically less than 0.2% for ungapped cores.
Low profile, small volume, for high power density equipment designs.
Unparalleled working frequency range : 50kHz to 1MHz.
Unmatched repeatability and predictability : All windings are pre- tooled.
Configurations for all Switchmode Power Supply (SMPS) topologies.
Multiple windings available (from one to seven secondaries).
10W - 20kW power ratings.
Efficient High cooling
High Efficient Heat dissipation and cooling
Low weight : 15g per 100W
Minimum Electromagnetic Interference (EMI).
Wide Operating temperature range : -40�C to +130�C.
Planar magnetics is probably the most cost effective solution for high frequency high power density power conversion equipments available today.
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