High Frequency LTCC based Planar Transformer

As we move towards high power and higher frequency related technology, conventional wire-wound magnetics have their own limitations which has led path to the development of planar based magnetic materials. Nowadays more planar magnetic technology has been employed because it is easier to fabricate them. The planar magnetic is a transformer or an inductor that replaces the wire-wound transformer or inductors which generally uses copper wires. One of the main reasons why we move to planar magnetic technology is its operation at higher frequency which provides higher power density. This study explains in detail about the design and fabrication of planar transformer for power electronics applications. The most important part of the transformer is its core. The cores in the planar transformer have different shapes and are available in different sizes. A planar core that is optimized, when compared with the conventional core with similar properties, exhibit better properties. In planar winding, we have different configurations available and with the optimum configuration, the losses of the transformer can be efficiently reduced. In this work, we have considered all the design specifications and came up with an optimum design procedure in order to design a good power planar transformer. This also deals with the case where the temperature rise is higher than what the PCB can withstand and try to come up with a solution for that. The next step for the planar transformer is to move from printed circuit board (PCB) to low temperature co-fired ceramic (LTCC) substrate which is attempted in this work. The main emphasis in this work is the design and fabrication procedure of LTCC based planar transformer. Ceramic can withstand higher temperature and has a better coefficient of thermal expansion (CTE) but has its own disadvantages which are also discussed here