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

摘要

Circuits are provided for protecting against negative overvoltages of a power supply in an integrated circuit including a power device (P). The protection circuits include a voltage limiting device (T4) interposed between supply and control terminals of the power device, as well as a switching device (T6). The switching device is interposed between a control terminal of the voltage limiting means and ground. The switching means is controlled by the power supply to cause conduction of the voltage limiting means for firing the power device if a positive overvoltage on the supply terminal (CL) of the power device is combined with a negative overvoltage of the power supply (Vb). In some embodiments the switching device and the voltage limiting device are both NPN transistors. In other embodiments the the switching device and the voltage limiting device are both MOS transistors.