Patent ID: 6803789
Filing Date: 2004-10-12
Classification: H03K

Abstract:
A driver having a high impedance state, the driver comprising:pull-up means, responsive to an output enable signal and an input data signal, for providing a low or high impedance path between a first supply voltage and an output node, the low impedance path being present when the output enable signal and the input data signal are both a logic high, the high impedance path being present when the either the output enable signal or the input data signal is a logic low, and the pull-up means being connected to a substrate bias voltage that is the greater of the output voltage when the pull-up means has a high-impedance path and the first supply voltage; pull-down means, responsive to the output enable signal and the input data signal, for providing a low or high-impedance path between the output node and a second supply voltage, the low impedance path being present when the output enable signal is a logic high and the input data signal is a logic low, and the high impedance path being present when the output enable signal is a logic low or the input data signal is a logic high; and inhibit means, responsive to a voltage on the output node, for operating on the pull-up means to block conduction from the output node to the first supply voltage when the pull-up means provides a high impedance.