Detector for detecting the polarity of an alternating signal

A device for detecting the polarity of an alternately positive and negative detected current or of an alternately positive or negative detected voltage, the detection device being configured to indicate the polarity of the detected current or of the detected voltage, the detection device comprising:

• a circuit portion provided with a detection node configured to produce at the detection node a measurement voltage image of a fraction of the detected current or of the detected voltage, and
• at least one detection circuit with transistor(s), coupled to the detection node, the at least one detection circuit being provided with one or more amplifier stage(s), at least one of the amplifier stages comprising a comparator transistor having a gate-source voltage which depends on the measurement voltage,
• the comparator transistor further having a source set at a fixed potential and a gate-source voltage which depends on the measurement voltage or a gate set at a fixed potential and a gate-source voltage which depends on the measurement voltage,
• the at least one detection circuit further comprising an output transistor having a drain coupled to an output, the output transistor having a gate coupled to the drain of the comparator transistor, and
• the at least one detection circuit being configured to compare the measurement voltage with a determined threshold, and produce at the output a binary detection signal indicative of the polarity of the detected current or of the detected voltage, the detection adopting a first state when the measurement voltage is below the determined threshold and adopting a second state when the measurement voltage is above the determined threshold,
• wherein the detection node is coupled to a source of an input transistor of the detection circuit or to the source of the comparator transistor, and
• wherein the input transistor, the comparator transistor, and the output transistor of the detection circuit are of the N type and normally blocked.