Patent ID: 6882513

Claim:
An electrical voltage protection circuit having at least one input terminal configured to receive an input voltage applied from a voltage source during operation, the protection circuit further having at least one output terminal, the protection circuit configured to provide an output voltage on the output terminal during operation, the protection circuit comprising the following: a field-effect transistor having a gate terminal, a source terminal, a drain terminal, and a body terminal, the source terminal of the field-effect transistor being coupled to an input terminal of the protection circuit, the drain terminal of the field-effect transistor being coupled to an output terminal of the protection circuit; a resistor coupled between the source terminal and the body terminal of the field-effect transistor; a voltage-current dependent circuit coupled between the gate terminal and the source terminal of the field-effect transistor, the voltage-current dependent circuit configured to apply a voltage difference between the gate terminal and the source terminal that is dependent on the current passing through the voltage-current dependent circuit; and a current application circuit coupled to the voltage-current dependent circuit and configured to apply a current through the voltage-current dependent circuit such that in at least some conditions when an overvoltage is not present, the voltage-current dependent circuit applies a voltage at the gate terminal of the field-effect transistor sufficient to turn or keep the field-effect transistor on.