Integrated circuit for automatic determination of PCI signaling environment--either 3.3V or 5V

摘要

An integrated circuit automatically detects a Peripheral Component Interconnect signaling environment, which may be based on either a first voltage or a second voltage, and matches output voltage and output current characteristics of an output signal with Peripheral Component Interconnect signal specifications. The integrated circuit includes a signaling environment detection circuit and an output driver circuit. The signaling environment detection circuit compares an integrated circuit supply voltage with a reference voltage, whose value is between the first voltage and the second voltage, and generates a detected environment signal representative of the signaling environment. The output driver circuit adjusts the output voltage and output current of the output signal to match the Peripheral Component Interconnect signal specifications based on the detected environment signal by sourcing additional current to the output pad to match the Peripheral Component Interconnect signal specifications when the detected environment signal indicates a signaling environment based on the first voltage, and sinking additional current from the output pad to match the Peripheral Component Interconnect signal specifications when the detected environment signal indicates a signaling environment based on the second voltage.