Monitoring circuit and corresponding method

Abstract

A circuit for monitoring an actual threshold voltage value of a MOSFET is provided. The circuit includes a current source configured to be coupled to a source terminal of the MOSFET and to generate a test current; a voltage generator configured to be coupled between a gate terminal of the MOSFET and the source terminal of the MOSFET, and to generate a test voltage, said test voltage being lower than a nominal threshold voltage value of the MOSFET; a detection unit configured to sample a plurality of voltage value at the source terminal of the MOSFET during time, to compute as a function of said plurality of voltage value at least a value of voltage variation over time, in particular over a given time period, of said voltage value at the source terminal of the MOSFET, and to provide said computed at least a value of voltage variation to an alarm generation unit; the alarm generation unit being configured to receive said computed voltage variation from the detection unit, to compare said computed voltage variation with a reference voltage, and to raise an alarm if the output of said comparison does not correspond to a predetermined output condition; and a control unit, configured to receive a test mode signal, indicative of an operation mode. The control unit is further configured to, according to said received test mode signal, select the status of coupling or decoupling of said current source to/from the source terminal of the MOSFET, determine the value of said reference voltage, set said output condition of said comparison, and signal to the detection unit to perform a plurality of said sampling operation.