Ceramic transformers offer big step up

Epcos has developed an innovative and extremely compact transformer based on piezoelectric technology.

Epcos has developed an innovative and extremely compact transformer based on piezoelectric technology.

The smallest one produced so far has a footprint of only 1.2 x 1.2mm.

The new transformer, which employs low-temperature cofired ceramic (LTCC) technology, was designed for front-end modules that are used in mobile communication terminals.

The ceramic transformer steps up the operating voltage of 1.2V by a factor of ten.

This makes it possible to drive extremely low-loss MEM switches for the duplexer.

Larger versions of the transformer measuring about 34 x 10mm can step up the supply voltage of automotive electrical systems (typically 12V) to as much as 16kV.

They can thus be used in ignition systems for internal combustion engines or high-intensity discharge lamps.

The ceramic transformer works on a strikingly simple principle.

An AC voltage applied to the input is converted into a mechanical vibration by the inverse piezoelectric effect.

This is retransformed at the output into a substantially higher AC voltage.

The efficiency of this transducer approach is higher than that of conventional transformers, which use magnetic energy as an intermediate stage.

The piezoelectric transformer features negligible electromagnetic interference as well as extremely compact dimensions and a drastic weight reduction in comparison with magnetic transformers.

Extra shielding and EMC measures are thus a thing of the past.

Also, a breakdown between the primary and secondary sides is ruled out because the piezoelectric transformer works without metal windings and is insulated by ceramic material.

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