Smart-power-switch type electronic relay with short-circuit and overload protection

摘要

An electronically controlled relay including a drive coil (L1) for actuating at least one mechanical switch (S1) and including a semiconductor switch (H1) connected in series with the drive coil (L1) and which is controlled as a function of an external in/out-control signal (IN1). A control circuit for the semiconductor switch (H1) is connected by means of two input terminals (EK1,EK2) to a conductor loop of the mechanical switch (S1), and is used to detect a voltage drop (VR) in the conductor loop and for outputting a signal (V3) for switching off the semiconductor switch (H1), if the detected voltage drop (VR) exceeds a given maximum value (RV1). A microcomputer is specifically used for electronic control of the drive circuit, in which the output signal (V2) of an NAND-gate (G1) is fed to the microcomputer as a status signal.