Over-voltage protection circuit

An over-voltage protection circuit for protecting an integrated circuit from an over-voltage, comprising:

• an external power supply terminal to which a power supply voltage is supplied,
• a grounding terminal to which a ground voltage is supplied,
• an internal power supply terminal for supplying a power supply voltage to the integrated circuit,
• voltage dividing means connected between the external power supply terminal and the grounding terminal for dividing the voltage supplied from the external power supply terminal, said voltage dividing means comprising a Zener diode and a first resistor connected in series,
• signal generating means connected between the external power supply terminal and the grounding terminal for outputting one of the power supply voltage and the ground voltage depending on a voltage at a connection point of the Zener diode and the first resistor in the voltage dividing means, and
• switching means connected between the internal power supply terminal and the signal generating means for performing an on/off switching operation depending on an output of the signal generating means.