A voltage domain is characterized by a reference voltage to which voltage signals occurring in the voltage domain are related. For signal transmission between two voltage domains having different reference potentials a signal transmission arrangement is required that allows signals to be transferred between the two domains but that prevents currents from flowing between the two voltage domains.
The two voltage domains may be implemented using integrated circuit devices. A signal transmission arrangement that is suitable for signal transmission between such voltage domains may be realized using integrated transformers that are also known as coreless transformers. A coreless transformer includes a primary and a secondary winding, these windings being arranged distant from one another and separated by a dielectric. The maximum voltage difference between the two voltage domains the transformer can withstand is dependent on the distance between the transformer windings and the isolation properties of the used isolation material (dielectric layer). The maximum difference voltage increases with increasing distance. However, thick dielectric layers, such as oxide layers, that are required for high voltage differences are difficult to produce with a sufficiently high accuracy and reliability using processes that are compatible with integrated circuits manufacturing processes.
USPTO Backgrounds
USPTO Backgrounds