Method and system for measuring the resistance of a resistive structure
AssigneeLinear Technology Corporation
InventorBernhard Helmut Engl
Life of this patent
Estimating the term…
Abstract
Method and system for measuring the resistance of a resistive structure having at least three nodes. A first calibration signal is determined by measuring a voltage at an output of the resistance structure when no calibration current is injected into a third node between the first and second nodes of the structure. A calibration current is then injected into the third node and a second calibration signal is determined. The absolute value of the difference between the first calibration signal and the second calibration signal is determined, the absolute value being proportional to a product of the resistance of the resistive structure and the calibration current.
Claims34
A system for measuring electrical resistance, comprising:
- a resistive structure having:
- a first node at a first end of the resistive structure;
- a second node at a second end of the resistive structure;
- and
- a third node on the resistive structure between the first and second nodes;
- a calibration current generation circuit having an output coupled to the third node of the resistive structure;
- and
- a signal conditioning circuit comprising:
- a first input coupled to the first node of the resistive structure;
- a second input coupled to the second node of the resistive structure;
- a third input coupled to the third node of the resistive structure;
- and
- an output,
- wherein the signal conditioning circuit is configured to provide at its output a signal proportional to a difference between a voltage at the third node and a weighted average of the voltages at the first and second nodes of the resistive structure.
A method of measuring resistance of a resistive structure having a first node at a first end of the resistive structure, a second node at a second end of the resistive structure, and a third node between the first node and the second node of the resistive structure and adapted to receive a calibration current;
- a signal conditioning circuit comprising a first input coupled to the first node of the resistive structure, a second input coupled to the second node of the resistive structure, a third input coupled to the third node of the resistive structure;
- and an output, the method comprising:
- determining a first calibration signal by measuring a voltage at the output when no calibration current is injected into the third node of the resistive structure;
- injecting a calibration current into the third node of the resistive structure;
- determining a second calibration signal by:
- interpolating voltages at the first and second nodes of the resistive structure;
- and
- subtracting the interpolated voltage from a voltage at the third node of the resistive structure;
- and
- determining an absolute value of a difference between the determined first calibration signal and the determined second calibration signal, wherein the absolute value is proportional to a product of the resistance of the resistive structure and the calibration current.
Dependencies are inferred from the claim text.