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Coreless transformer a new technology for half bridge driver IC´s

To drive the high side switch in a half bridge configuration it is necessary to transmit signals from the micro controller to the floating high side potential. Depending on the performance level of the drive circuit either HV IC´s with different kinds of level shifters, opto-couplers or transformers are employed for signal interchange. HV IC´s with level shifters are comparably inexpensive, but they cannot on principle grant galvanic isolation. Opto-couplers on the other hand do provide safe isolation, but they degrade over time. Especially in high performance drives discrete transformers are the common solution, although they are rather expensive. By integrating both windings of a coreless transformer on a silicon die, Infineon Technologies in cooperation with eupec developed a cost effective solution, that incorporates the advantages of a transformer into an IC. This paper describes the technology used to build a first half bridge driver IC. First measurements on signal transmission as well as insulation voltage are shown. Being capable of integrating various functions into the IC, potential features for a half bridge driver are discussed.

• 844.28 KB
• Feb 07, 2014