An electronic device includes a first device terminal and a second device terminal. A first and a second thyristor are reverse-connected between the two device terminals. A first and a second MOS transistor are respectively coupled between the conduction electrodes (emitters and collectors) of the two NPN transistors of the two thyristors. A third MOS transistor is coupled between the emitters of the two NPN bipolar transistors of the two thyristors and a fourth MOS transistor is coupled between the bases of the two PNP bipolar transistors of the two thyristors. A gate region is common to all the MOS transistors and a semiconductor substrate region includes the substrates of all the MOS transistors.