Patent ID: 6703873
Filing Date: 2004-03-09
Classification: H03K

Abstract:
A pull-up circuit for an input/output terminal of an electronic appliance, said circuit being arranged between the input/output terminal and a supply voltage terminal, the circuit comprising:a first transistor and a resistance that are serially connected and coupled between said input/output terminal and said supply voltage terminal; and circuitry suitable for driving said transistor so as to switch it on or off depending on whether values achieved by a voltage of the input/output terminal belong or do not belong to a set range of voltage values that includes a supply voltage of the supply voltage terminal, wherein said circuitry comprises: a first device for driving said first transistor, said first device comprising a plurality of MOS transistors having respective bulk terminals; and a second device coupled to the bulk terminals and structured to bias the bulk terminals of said MOS transistors and a bulk terminal of the first transistor at the higher of either a voltage value at or slightly below the voltage on the input/output terminal and a voltage value near the supply voltage.