High resolution current sensing apparatus
First Claim
1. A current sensor comprising:
- a magnetic field source for generating a magnetic field;
a current sensing system including a sensing element and a nulling element, the sensing element disposed in the magnetic field and configured to receive a current to be sensed, the sensing element being deflectable under the influence of the magnetic field and the current, the nulling element being linked to the sensing element and disposed in the magnetic field, the nulling element being configured to receive a nulling current to resist deflection of the sensing element; and
a feedback element coupled to the current sensing system and configured to produce a signal representative of deflection of the sensing element.
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Abstract
A current sensor includes a deflectable member disposed in a magnetic field. Nulling or compensating members may be mechanically coupled to the deflectable member, Feedback or readout devices coupled to the structure provide signals indicative of deflection of the deflectable member under the influence of applied current and the magnetic field. Nulling current applied to the nulling members tends to oppose deflection of the deflectable member. The nulling current may be modulated to drive the feedback signal to a desired level and is used as a basis for calculating the current to be measured. The current may be measured directly upon calibration of feedback devices coupled to the deflectable member or to the nulling members. Arrays of sensors may be coupled to common busses for applying measured and nulling currents to sensors of the arrays and for detecting feedback signals.
19 Citations
31 Claims
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1. A current sensor comprising:
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a magnetic field source for generating a magnetic field;
a current sensing system including a sensing element and a nulling element, the sensing element disposed in the magnetic field and configured to receive a current to be sensed, the sensing element being deflectable under the influence of the magnetic field and the current, the nulling element being linked to the sensing element and disposed in the magnetic field, the nulling element being configured to receive a nulling current to resist deflection of the sensing element; and
a feedback element coupled to the current sensing system and configured to produce a signal representative of deflection of the sensing element. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A current sensor comprising:
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a magnetic base for producing a magnetic field;
an insulating layer disposed adjacent to the base;
a micromachined current sensing system disposed within the magnetic field and configured to receive a current to be measured and to deflect under the influence of the current and the magnetic field; and
a readout device coupled to the sensing system for determining deflection of the beam. - View Dependent Claims (8, 9, 10, 11, 12, 13, 15, 16, 17, 19, 20, 21, 22, 23, 24, 25, 27, 28, 29, 30, 31)
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14. A current sensor comprising:
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a magnetic field source for producing a magnetic field;
an elongated sensing element disposed within the magnetic field, the sensing element being configured to receive a current to be measured and to deflect from a normal position under the combined influence of the magnetic field and the current;
first and second compensation elements disposed on first and second sides, respectively, of the sensing element and coupled to the sensing element, each compensation element being configured to receive a compensation current and to restrain the sensing element from deflection under the influence of the magnetic field and the compensation current; and
first and second feedback devices coupled to the compensation elements for sensing deflection of the sensing element.
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18. A current sensor comprising:
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a substrate including a magnetic field source and at least one insulating layer;
a device layer disposed over the substrate and forming a deflectable current sensing structure, a readout device, and a link between a portion of the readout device and the sensing structure, the device layer including at least a conductive layer forming conductive paths on the sensing structure and conductive regions on the readout device, and a non-conductive layer forming the link between the readout device and the sensing structure, and a support layer disposed between the device layer and the substrate, the support layer bounding a cavity between the device layer and the substrate to support the sensing structure and the readout device while allowing deflection of the sensing structure under the influence of a measured current and a magnetic field from the field source.
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26. , A current sensor comprising:
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a plurality of current sensing modules, each module including a deflectable sensing structure and a readout element coupled to the sensing structure for generating an output signal as a function of deflection of the sensing structure;
an input bus coupled to the sensing structures for applying a current to be measured;
an output bus coupled to the sensing structures for receiving the current to be measured; and
a readout bus coupled to the readout elements to detect the output signals.
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Specification