Patent ID: 7957111

Claim:
An output driver in an integrated circuit, comprising: a differential current output driver circuit operable by a power supply voltage and including first and second driver transistors in a differential current configuration and first and second output pads; and an overvoltage protection circuit comprising a first driver power conditioner configured to provide a first fractional pad voltage as a first protected voltage in response to an absence of the power supply voltage; a second driver power conditioner configured to provide a second fractional pad voltage as a second protected voltage in response to an absence of the power supply voltage; and a maximum value detector configured to select a maximum value of the first and second protected voltages and to provide the selected maximum value to the differential current output driver circuit as a composite protected voltage, wherein the overvoltage protection circuit is configured to generate a protected voltage in response to a voltage on at least one of the first and second output pads and an absence of the power supply voltage, and to apply the protected voltage to at least one transistor of the differential current output driver circuit.