Circuit and method for determining potentiometer wiper resistance
First Claim
1. A method of determining wiper resistance of a potentiometer including a first terminal, a second terminal, a third terminal, a resistive element having a potentiometer resistance electrically coupled between the first and second terminals, and a wiper electrically coupled between the resistive element and the third terminal and movable to a wiper position between the first and second terminals, the method comprising the steps of:
- electrically energizing the potentiometer;
electrically coupling a sense resistor to the potentiometer third terminal, the sense resistor having a substantially constant sense resistance;
determining a potentiometer voltage, the potentiometer voltage being a voltage potential between the potentiometer first and second terminals;
determining the wiper position based at least in part on the determined potentiometer voltage;
electrically coupling the sense resistor to a potential that causes a wiper current to flow through the wiper and sense resistor;
determining a magnitude of the wiper current; and
determining the wiper resistance based at least in part on the potentiometer resistance, the determined potentiometer position, the determined wiper current magnitude, and the sense resistance.
1 Assignment
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Accused Products
Abstract
A circuit and method for determining the wiper resistance of a potentiometer that includes a first terminal, a second terminal, a third terminal, a resistive element having a potentiometer resistance electrically coupled between the first and second terminals, and a wiper electrically coupled between the resistive element and the third terminal and movable to a wiper position between the first and second terminals, includes the step of electrically coupling a sense resistor having a substantially constant sense resistance to the potentiometer third terminal. The potentiometer is electrically energized, and a potentiometer voltage, which is a voltage potential between the potentiometer first and second terminals, is determined. The wiper position is determined based at least in part on the determined potentiometer voltage. The sense resistor is electrically coupled to a potential that causes a wiper current to flow through the wiper and sense resistor. A magnitude of the wiper current is determined, and the wiper resistance is determined based at least in part on the potentiometer resistance, the determined potentiometer position, the determined wiper current magnitude, and the sense resistance.
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Citations
20 Claims
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1. A method of determining wiper resistance of a potentiometer including a first terminal, a second terminal, a third terminal, a resistive element having a potentiometer resistance electrically coupled between the first and second terminals, and a wiper electrically coupled between the resistive element and the third terminal and movable to a wiper position between the first and second terminals, the method comprising the steps of:
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electrically energizing the potentiometer; electrically coupling a sense resistor to the potentiometer third terminal, the sense resistor having a substantially constant sense resistance; determining a potentiometer voltage, the potentiometer voltage being a voltage potential between the potentiometer first and second terminals; determining the wiper position based at least in part on the determined potentiometer voltage; electrically coupling the sense resistor to a potential that causes a wiper current to flow through the wiper and sense resistor; determining a magnitude of the wiper current; and determining the wiper resistance based at least in part on the potentiometer resistance, the determined potentiometer position, the determined wiper current magnitude, and the sense resistance. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A potentiometer wiper resistance measurement circuit, comprising:
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a potentiometer including a first terminal, a second terminal, a third terminal, a resistive element having a potentiometer resistance electrically coupled between the first and second terminals, and a wiper electrically coupled between the resistive element and the third terminal and movable to a wiper position between the first and second terminals; a sense resistor having a substantially constant sense resistance and including a first terminal and a second terminal, the sense resistor first terminal coupled to the potentiometer third terminal; a power source electrically coupled to the potentiometer and configured to supply a current thereto that results in a voltage drop between the potentiometer first and second terminals; and an output circuit having a plurality of input terminals and an output terminal, separate ones of the output circuit input terminals coupled to at least the potentiometer first terminal, the potentiometer second terminal, and the sense resistor second terminal, the output circuit operable to selectively couple (i) the potentiometer first terminal to the output terminal, (ii) the potentiometer third terminal to the output terminal, and (iii) the sense resistor second terminal to a reference potential. - View Dependent Claims (12, 13, 14, 15, 16, 17, 20)
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18. A potentiometer wiper resistance measurement circuit, comprising:
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a potentiometer including a first terminal, a second terminal, a third terminal, a resistive element having a potentiometer resistance electrically coupled between the first and second terminals, and a wiper electrically coupled between the resistive element and the third terminal and movable to a wiper position between the first and second terminals; a sense resistor having a substantially constant sense resistance and including a first terminal and a second terminal, the sense resistor first terminal coupled to the potentiometer third terminal; a power source electrically coupled to the potentiometer and configured to supply a current thereto that results in a voltage drop between the potentiometer first and second terminals; a first multiplexer having a plurality of input terminals and an output terminal, a first of the input terminals coupled to the potentiometer first terminal, a second of the input terminals coupled to the potentiometer third terminal; a second multiplexer having a plurality of input terminals and an output terminal, a first of the input terminals coupled to the sense resistor second terminal; a third multiplexer having a plurality of input terminals and an output terminal, a first of the input terminals coupled to the reference potential, the output terminal coupled to the second multiplexer output terminal; and a fourth multiplexer having a plurality of input terminals and an output terminal, a first of the input terminals coupled to the first multiplexer output terminal, a second of the input terminals coupled to the second multiplexer output terminal. - View Dependent Claims (19)
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Specification