Abstract: A method and apparatus for maintaining the voltage level of data signals supplied to an integrated circuit, such as a PCMCIA card, at the same level as power also provided to the integrated circuit. Circuitry for maintaining the voltages at the same level is preferably embodied within a system having a card controller integrated circuit, a power supply, and a peripheral card socket for receiving a removable PCMCIA card. The power supply is controlled by the card controller to provide power to the PCMCIA card through the card socket at a voltage level matching internal voltage requirements of the PCMCIA card. The card controller is connected directly to the PCMCIA card by a signal transmission line. Circuitry is provided for ensuring that the voltage of data signals transmitted along the data bus line to the PCMCIA card substantially match the voltage of power provided from the power supply to the PCMCIA card along a power supply line.

Abstract: The design and implementation of a low power CMOS bi-directional I/O buffer that translates low voltage core logic level signals into the highest logic level signals to drive the final output stage which outputs a selectable logic level signal. The buffer further translates input signals of a variety of logic levels into low voltage core logic level signals. In either case, AC and DC power consumption is minimized in a mixed power supply environment that requires voltage translation to represent the proper binary logic levels. An multivoltage I/O buffer having multiple input-receiving NOR gates is also described. The NOR gates of the multivoltage I/O buffer having triggering levels optimized for differing core voltage levels. Also described is a host adapted system for interfacing between and removable peripheral card and a host computer. The host adaptor includes an integrated circuit employing the multivoltage bi-directional I/O buffer.