Monolithic magnetic sensor having externally adjustable temperature compensation
First Claim
1. A Hall-effect device, comprising:
- a Hall-effect element having at least one input for receiving a bias signal and at least one output for providing an output signal dependent on the bias signal and a magnetic field intercepting the Hall-effect element;
at least one output lead to provide an output signal responsive to the output signal of the Hall-effect element and dependent on an overall gain of the Hall-effect device; and
a temperature-variable gain control circuit coupled to the Hall-effect element to adjust a sensitivity of the overall gain of the Hall-effect device to temperature changes, the temperature-variable gain control circuit including a pair of nodes and being configured such that, when a first component is coupled between the pair of nodes, changing a characteristic of only the first component alters a sensitivity of the overall gain of the Hall-effect device to temperature changes without altering the overall gain of the Hall-effect device when the Hall-effect device is maintained at a reference temperature.
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Accused Products
Abstract
The current flow from a temperature-variable current source to a Hall-effect element is adjusted according to sensed temperature conditions of the element to compensate for temperature-dependent changes in the magnetic-field sensitivity of the Hall-effect element and in the magnitude of the permanent magnetic fields of magnetic components sensed by the element. A trimmable resistor is connected between two external terminals of a Monolithically integrated circuit to provide external control over the sensitivity of the temperature variable current source to changing temperature conditions. The device also alternately switches the quadrature states of output and bias supply contacts of the Hall-effect element to compensate for the offset and drift thereof.
44 Citations
48 Claims
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1. A Hall-effect device, comprising:
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a Hall-effect element having at least one input for receiving a bias signal and at least one output for providing an output signal dependent on the bias signal and a magnetic field intercepting the Hall-effect element; at least one output lead to provide an output signal responsive to the output signal of the Hall-effect element and dependent on an overall gain of the Hall-effect device; and a temperature-variable gain control circuit coupled to the Hall-effect element to adjust a sensitivity of the overall gain of the Hall-effect device to temperature changes, the temperature-variable gain control circuit including a pair of nodes and being configured such that, when a first component is coupled between the pair of nodes, changing a characteristic of only the first component alters a sensitivity of the overall gain of the Hall-effect device to temperature changes without altering the overall gain of the Hall-effect device when the Hall-effect device is maintained at a reference temperature. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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9. A Hall-effect device, comprising:
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a Hall-effect element having at least one input for receiving a bias signal and at least one output for providing an output signal dependent on the bias signal and a magnetic field intercepting the Hall-effect element; at least one output lead to provide an output signal responsive to the output signal of the Hall-effect element and dependent on an overall gain of the Hall-effect device; and means, coupled to the Hall-effect element, for enabling a sensitivity of the overall gain of the Hall-effect device to changing temperature conditions to be adjusted by changing a value of only a single component coupled to the means for enabling without altering the overall gain of the Hall-effect device when the Hall-effect device is maintained at a reference temperature. - View Dependent Claims (10, 23)
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11. A method for compensating for the effects of temperature variations on a Hall-effect element and/or a magnet generating a magnetic field being measured thereby, comprising steps of:
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(a) providing a Hall-effect device including a Hall-effect element and a temperature-variable gain control circuit coupled to the Hall-effect element to adjust a sensitivity of a gain of the Hall-effect device to temperature changes; (b) coupling a first component between a pair of nodes of the temperature-variable gain control circuit to set the sensitivity of the gain of the Hall-effect device to temperature variations; and (c) altering a characteristic of only the first component to adjust the sensitivity of the gain of the Hall-effect device to temperature variations without altering the gain of the Hall-effect device when the Hall-effect device is maintained at a reference temperature. - View Dependent Claims (12, 24, 25)
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26. A Hall-effect device, comprising:
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a Hall-effect element having at least one input for receiving a bias signal and at least one output for providing an output signal, the output signal representing a product of a strength of a magnetic field intercepting the Hall-effect element, an amplitude of the bias signal, and a sensitivity constant of the Hall-effect element, wherein the sensitivity constant of the Hall-effect element changes with temperature changes of the Hall-effect element such that, if the amplitude of the bias signal and the strength of the magnetic field were held constant, a magnitude of the output signal would change in a particular polarity direction as a temperature of the Hall-effect element increased; at least one output lead to provide an output signal responsive to the output signal of the Hall-effect element and dependent on an overall gain of the Hall-effect device; and a temperature-variable gain control circuit coupled to the Hall-effect element, the temperature-variable gain control circuit including at least one pair of nodes between which at least one component can be coupled to set a sensitivity of the overall gain of the Hall-effect device to changing temperature conditions, the temperature-variable gain control circuit being configured such that, when the at least one component is coupled between the at least one pair of nodes and a characteristic of at least the at least one component has a first value, an amount that the overall gain of the Hall-effect device changes in the particular polarity direction in response to a given increase in temperature is greater than an amount that the overall gain of the Hall-effect device would change in the particular polarity direction in response to the given increase in temperature if the temperature-variable gain control circuit did not alter the overall gain of the Hall-effect device in response to changing temperature conditions. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40)
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41. A Hall-effect device, comprising:
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a Hall-effect element having at least one input for receiving a bias signal and at least one output for providing an output signal dependent on the bias signal and a magnetic field intercepting the Hall-effect element; a variable signal source coupled to the Hall-effect element to provide the bias signal thereto; and means for selectively increasing an amplitude of the bias signal as a temperature of the Hall-effect device increases, and for selectively decreasing the amplitude of the bias signal as the temperature of the Hall-effect device increases. - View Dependent Claims (42)
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43. A Hall-effect device, comprising:
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a Hall-effect element having at least one input for receiving a bias signal and at least one output for providing an output signal dependent on the bias signal and a magnetic field intercepting the Hall-effect element; at least one output lead to provide an output signal responsive to the output signal of the Hall-effect element and dependent on an overall gain of the Hall-effect device; a voltage divider having at least first, second, and third nodes, a voltage at the second node of the voltage divider representing a particular proportion of a difference between voltages at the first and third nodes of the voltage divider; a temperature-sensitive voltage source to provide an output voltage responsive to temperature changes, the temperature-sensitive voltage source being coupled to the first node of the voltage divider to provide the output voltage thereto; and a gain control circuit coupled to the Hall-effect element to, in response to a control voltage, adjust a sensitivity of the overall gain of the Hall-effect device to temperature changes, the gain control circuit being coupled to the second node of the voltage divider to receive the control voltage therefrom. - View Dependent Claims (44, 45, 46, 47, 48)
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Specification