Smaller PSU designs enabled by ceramic material 's properties

June 12, 2013 // By Christoph Hammerschmidt
Siemens scientists have developed novel ceramic materials to embed transformers. The high thermal conductance of the material allows designers to reduce the size of power supplies and LED drivers by as much as 80%.

LEDs, in particular, can benefit from the new technology: Their switching power supply is typically located separately from the LED light bulb: the new ceramic material allowsintegration of the power supply into the heat sink of the luminaire.

This technology has been developed by Siemens, along with research partners from industry and science, within the scope of the ALFerMO research programme.

Many devices used in building and traffic control, and automation, as well as LED luminaires, require electronic power supplies or drivers that are often space consuming, preventing a compact system design. Items that are particularly difficult to shrink include transformers with their magnetic ferrite core and metallic coils. With their properties they determine the extent to which an electronic building block such as an LED driver or a switching power supply can be shrunk.

Using 16 Osram Oslon LED luminaires as an example, the ALFerMo consortium demonstrated how to integrate the power supply into a recess of the heat sink. The researchers applied two tricks to shrink the transformer: they used a much higher switching frequency, and also  developed a layered structure consisting of magnetic ceramic films, which allowed integration of the ferrite core along with the transformer windings into a ceramic PCB. It was therefore possible to shrink the transformer to one fifth of its original size and to integrate the driver circuitry into an LED heat sink with a diameter of 10 cm and a height of 5 cm.

The engineers and scientists in the ALFerMo project have made progress in driving the integration PCBs for modular, compact power electronics assemblies: in addition, the consortium examined applications of this approach in the conventional epoxy PCB materials, as well as for applications beyond lighting technology.