TEMPERATURE-COMPENSATED SHUNT CURRENT MEASUREMENT
First Claim
1. A current sensor, comprising:
- a shunt, configured for conveying an electric current, and having a resistance which varies with a temperature of said shunt;
a first resistant element connected between said shunt and a first output terminal, at least a portion of said first resistant element being in thermal contact with a first predetermined location subject to thermal drift on said shunt, and having a resistance which varies in accordance with a temperature of said shunt, such that a change in the resistance of said shunt causes a compensating change in the gain of an associated amplifier; and
a second output terminal, said first and second output terminals being configured for measurement of a voltage over said shunt.
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Accused Products
Abstract
A current sensor includes a shunt and at least one resistant element. The shunt conveys an electric current, and has a resistance which varies with the shunt'"'"'s temperature. A resistant element, which has a resistance that varies with its own temperature, is electrically connected between the shunt and an output terminal of the current sensor. At least a portion of the resistant element is in thermal contact with a predetermined location on the shunt, so that the resistant element'"'"'s resistance varies in accordance with the shunt temperature. The current sensor may be connected to an amplifier whose gain varies in accordance with the resistance of the resistant element. The variation in the resistance of the resistant element causes a change in the amplifier gain, which compensates for changes in the shunt resistance due to change'"'"'s in the shunt'"'"'s temperature. In some embodiments, a second resistant element is connected between the shunt and a second output terminal.
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Citations
26 Claims
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1. A current sensor, comprising:
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a shunt, configured for conveying an electric current, and having a resistance which varies with a temperature of said shunt; a first resistant element connected between said shunt and a first output terminal, at least a portion of said first resistant element being in thermal contact with a first predetermined location subject to thermal drift on said shunt, and having a resistance which varies in accordance with a temperature of said shunt, such that a change in the resistance of said shunt causes a compensating change in the gain of an associated amplifier; and a second output terminal, said first and second output terminals being configured for measurement of a voltage over said shunt. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A current measurement unit, for providing an output for measuring the current through a shunt, wherein said shunt has a resistance which varies with a temperature of said shunt, comprising:
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an amplifier, configured for amplifying a voltage drop across said shunt, and having a gain determined by a total resistance between said shunt and said amplifier; and a first resistant element connected between said shunt and a first amplifier input, in thermal contact with a first predetermined location subject to thermal drift on said shunt, and having a resistance which varies in accordance with said temperature of said shunt, such that a change in shunt resistance causes a compensating change in amplifier gain. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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19. A method for measuring a current through a shunt, wherein said shunt has a resistance which varies with a temperature of said shunt, comprising:
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outputting a shunt voltage signal through an output resistance which varies in accordance with a temperature of a predetermined location subject to thermal drift on said shunt; and amplifying said output voltage signal by a gain determined by said output resistance, such that a change in shunt temperature causes a compensating change in amplifier gain. - View Dependent Claims (20)
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21. A method for providing a current measurement unit comprising:
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providing a current sensor having a shunt, a first terminal and a second terminal; and attaching a first resistant element between said shunt and said first terminal such that at least a portion of said first resistant element is in thermal contact with a first predetermined location subject to thermal drift on said shunt, wherein a resistance of said first resistant element varies in accordance with a temperature of said shunt, thereby to provide an output stabilized for changes in shunt temperature. - View Dependent Claims (22, 23, 24, 25)
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26. A current measurement unit for providing an output for measuring the current through a shunt, wherein said shunt has a resistance which varies with a temperature of said shunt, comprising:
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a controllable-gain amplifier, configured for amplifying an input signal with a gain determined by a gain control signal; and a gain control element associated with said amplifier, in thermal contact with a location subject to thermal drift on said shunt, configured for providing a gain control signal to said amplifier in accordance with a temperature at said location such that a change in shunt temperature causes a compensating change in amplifier gain.
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Specification