Optocoupler built-in self test for applications requiring isolation

摘要

An optocoupler circuit arrangement includes an isolated power source for producing a bipolar test signal, an analog multiplexer switching matrix coupled to the isolated power source for receiving and distributing the test signal, control logic for controlling the analog multiplexer switching matrix, and a plurality of optocouplers, each having a respective electrically isolated output circuit and an input circuit for receiving input signals from an external source. The optocoupler input circuits are coupled to the analog multiplexer switching matrix to receive respective test signals therefrom under control of the control logic. Blocking circuitry is provided at the optocoupler input for isolating the test signals from the external source.