Weak Pull-Up Circuits And Methods Having Leakage Current Compensation
AssigneeAltera Corporation
InventorsPai Ho Bong, Navindra Navaratnam, Seh Leong Goh
Life of this patent
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Abstract
An integrated circuit includes an output driver circuit coupled to a pad of the integrated circuit. The integrated circuit also includes a weak pull-up circuit coupled to the pad. The weak pull-up circuit includes a resistor and a leakage current sensing circuit coupled to the resistor. The leakage current sensing circuit generates a compensation current in the resistor that compensates for a leakage current through the output driver circuit when the output driver circuit is disabled.
Claims20
An integrated circuit comprising:
- an output driver circuit coupled to a pad of the integrated circuit;
- and
- a weak pull-up circuit coupled to the pad, wherein the weak pull-up circuit comprises a resistor and a leakage current sensing circuit coupled to the resistor, and wherein the leakage current sensing circuit generates a compensation current in the resistor that compensates for a first leakage current through the output driver circuit when the output driver circuit is disabled.
A method for operating a weak pull-up circuit in an integrated circuit, the method comprising:
- enabling the weak pull-up circuit, wherein the weak pull-up circuit is coupled to a pad of the integrated circuit;
- and
- generating a compensation current in the weak pull-up circuit based on a first leakage current through a first transistor, wherein the compensation current compensates for a second leakage current from the pad through an output driver circuit when the output driver circuit is disabled.
A weak pull-up circuit comprising:
- a first transistor that is biased in an off state;
- a current mirror circuit that generates a first current based on a second current through the first transistor;
- and
- a resistor, wherein the first current is provided through the resistor to a pad, and wherein the first current compensates for a leakage current through an output driver circuit that is coupled to the pad and to the weak pull-up circuit.
Dependencies are inferred from the claim text.