In industrial environments, galvanic isolation of circuit components is often required. Capacitive digital isolators make it easy to transmit desired signals safely and reliably via an isolation barrier. An example circuit shows their possible applications.
Two major challenges for electronics in typical industrial environments are interference-free data communication and the safety of people. Strong electromagnetic fields, overvoltages, transient voltages and high EMC interference are commonplace.
For example, when the temperature of a motor is measured with a thermocouple, voltages in the millivolt range are generated. If these voltages are now transmitted over a cable length of several meters to a central control unit that refers to a different ground potential, the measurement signal is distorted by the potential differences.
If the phenomena described are summarized, the following four challenges arise:
This application note presents a robust, interference-free design in analog circuit technology that can be used, for example, to measure voltage over long distances in distributed industrial plants. The circuit comprises a transmitter and a receiver, which are connected via a twisted two-wire cable and galvanically decoupled from each other with capacitive digital isolators.
Download: ANS020
