Schaltkreis zur Erkennung von Kurzschlüssen von Steuereinrichtungen für induktive Lasten

摘要

A circuit for detecting short-circuiting between the supply line (VCC) and output (T) of a drive device (1) comprising a switch (2) defining the output terminal (T) of the device to which is connected an inductive load (L), the other terminal of which is connected to the supply line (VCC); two current recirculating branches (18, 20; 26) connectable parallel to the load (L); and a control unit for opening and closing the switch (2) so that the load (L) is supplied with current rising to a first predetermined value in a first increasing phase, falling to a second predetermined value in a first recirculating phase, then oscillating about a hold value in subsequent increasing and recirculating phases. The detecting circuit comprises two current sensors (60, 61) each designed to detect the current flowing in a respective recirculating branch (18, 20; 26) in the first recirculating phase and in subsequent recirculating phases respectively. The current sensors (60, 61) are connected to a fault signaling circuit (73-85) for producing a fault signal in the absence of current in the recirculating branches during the recirculating phases.