Circuit for protection against negative overvoltages across the power supply of an integrated circuit comprising a power device with related control circuit

A protection circuit for protecting an integrated circuit including a power device and a control circuit therefor against negative overvoltages of a power supply, comprising:

• a voltage limiting switch interposed between a supply terminal and a control terminal of the power device, said voltage limiting switch comprising a transistor of one conductivity type;
• and
• Switching means interposed between a control terminal of the voltage limiting switch and ground, the switching means comprising a transistor having the same conductivity type as that of the transistor of said voltage limiting switch and having a control terminal connected to said power supply to cause the voltage limiting switch to fire the power device if a negative overvoltage of said power supply is combined with a positive overvoltage on the supply terminal of the power device, and wherein said power device comprises a transistor having the same conductivity type as the transistor of both the voltage limiting switch and the switching means.