A circuit for protection against polarity reversal in the supply of an electric circuit

摘要

A protection circuit is described for an electric circuit (L) to protect against supply polarity reversal, operable to allow a flow of current from a DC voltage supply source (B) towards a circuit (L) and to prevent current flowing in an opposite sense. <??>It comprises a controlled electronic switch (M1) such as a p-channel MOSFET transistor, intended to be interposed in a supply line between a positive voltage terminal of the source (B) and the circuit (L), and to be rendered selectively conductive by an associated driving circuit. <??>The driving circuit is arranged to detect polarity of the voltage capable of being applied to the circuit (L) and the sense of the current, and to emit a control signal operable to command the switch (M1) to a conduction state when the terminal coupled to the supply line has indeed a positive voltage and the current is supplied to the load, and to a turned off state in the case of polarity and /or current reversal. <IMAGE>