Method and apparatus for improving the tolerance of integrated resistors
AssigneeLSI Logic Corporation
InventorsClyde Washburn, Robert Bowman
Life of this patent
Estimating the term…
Abstract
A deice maximizes the allowable granularity of adjustment of a bus driver line characteristics by compensating for temperature variations by selecting components that have an opposite and approximately equal thermal coefficient. In the first aspect, component parts may be made smaller because their tolerances need not be made so precise. In the second aspect, duplicating the circuitry with matching characteristics allows one circuit to be operational while the other circuit is tested or dormant. Switching between the two circuits is performed seamlessly with no interruption of device operation.
Claims41
A bus driver circuit, comprising:
- a plurality of sets of switchable subcircuits, each of the sets of switchable subcircuits having an output, the outputs of all the switchable subcircuits being combined to form a single driver bus line,
- wherein each of the switchable subcircuits contains two subcomponents which have thermal coefficients which are approximately equal in magnitude but opposite in sign.
A bus driver circuit, comprising:
- a plurality of sets of switchable subcircuits, each of the sets of switchable subcircuits having an output, the outputs of all the switchable subcircuits being combined to form a single driver bus line,
- wherein each of the plurality of sets of switchable subcircuits contains a differing number of switchable subcircuits.
A method for optimizing transmission line switching characteristics, comprising:
- forming first and second circuits using the same process at the same time, the first and second circuits being formed in close proximity to each other, the first and second circuits each having an output and having two or more input lines, the first and second circuits each having at least one resistor and at least one transistor paired together so that the at least one resistor and the at least one transistor have substantially equal magnitudes of opposite sign;
- and
- forming output switching circuitry which receives the outputs of the first and second, circuits and which switches one of the outputs to a load while the other output is either connected to testing circuitry or is unconnected.
A method for optimizing transmission line switching characteristics, comprising:
- forming first and second circuits using the same process at the same time, the first and second circuits being formed in close proximity to each other, the first and second circuits each having an output and having two or more input lines, the first and second circuits being scaled in relation to one another so that their outputs have electrical characteristics in a determinable relationship to one another;
- and
- forming output switching circuitry which receives the outputs of the first and second circuits and which switches one of the outputs to a load while the other output is either connected to testing circuitry or is unconnected.
An electronic circuit arrangement for maintaining a given voltage for a given current over an extended temperature range, comprising:
- a field effect transistor having a non-zero thermal coefficient of a first polarity and a first magnitude;
- and
- a resistor having a non-zero thermal coefficient of a second polarity and being of a second magnitude essentially equal to the first magnitude, the second polarity being opposite in sign to the first polarity, the field effect transistor and the resistor being electrically coupled at a node, the resistor being switchably capable of providing all or a portion of an output signal.
A bus driver circuit, comprising:
- a field effect transistor having a non-zero thermal coefficient of a first polarity and a first magnitude;
- and
- a resistor having a non-zero thermal coefficient of a second polarity and a second magnitude essentially equal to the first magnitude, the second polarity being opposite in sign to the first polarity, the field effect transistor and the resistor being electrically coupled at a node, the resistor being capable of switchably providing all or part of an output signal from the bus driver circuit.
Dependencies are inferred from the claim text.