Galvanic interface separation
Galvanic isolation is the interruption of the metallic power line between two system components while maintaining the transport of power or data.
In the IT sector, interfaces are the connection of two or more components via cables and/or plug connections. For this purpose, the data is converted into a mutually understandable form (usually via data protocols) before being transferred to other components. Since the data transfer is usually carried out by means of power cables or conductor paths, these transfer paths are exposed to overvoltage pulses and other interference. In order to create insensitivity, a form of transmission is chosen that works without a power line.
In this environment, optical or radio transmission methods are usually used for signalling. The WLAN segment can be regarded as a radio method. Optical transmission uses optocouplers or fibre optic cables.
In order to galvanically separate data cables, coupling elements are inserted into the circuits. This avoids metallic connections between the circuits. These are common in serial cables, USB cables and twisted pair cables in LANs. SMD chips are used here, which are installed on the conductor tracks in the housings to save space. Depending on the design, such adapters must also be supplied with operating voltage. With USB 2.0, the connection must be equipped with 5V 500mA voltage. That is why additional power supplies are used here.