Patent ID: 6759872
Filing Date: 2004-07-06
Classification: H03K

Abstract:
An input/output (I/O) circuit, comprising:a pair of buffers, each of which is configured to produce an output signal having a signal swing responsive to an input signal; an output stage operably coupled to the pair of buffers, that is configured to receive the output signals of the pair of buffers, the output stage coupled between a first supply voltage and ground; a voltage reference circuit, operably coupled to the pair of buffers, that is configured to provide first and second reference voltages to the pair of buffers respectively, wherein the signal swing of each of the pair of buffers is based respectively, at least in part, on the first and second reference voltages; and a detection circuit, operably coupled to the voltage reference circuit that is configured to detect whether the first supply voltage is below a switching voltage and to control the voltage reference circuit to set the first and second reference voltages to first and second predetermined values, respectively, if the supply voltage is below the switching voltage so as to obtain signal swings between the supply voltage and ground.