Hall effect device with epitaxal layer resistive means for providing temperature independent sensitivity
First Claim
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1. A temperature compensated integrated circuit Hall effect device comprising:
- a substrate having an epitaxial layer thereon;
a Hall effect element formed in said epitaxial layer, said Hall effect element having first and second output terminals between which is produced a voltage difference indicative of the magnitude of an applied magnetic field; and
amplifier means connected to the first and second output terminals of said Hall effect element for receiving a voltage difference produced in response to a magnetic field and producing an output voltage whose magnitude is substantially linearly related to the magnitude of the magnetic field over an extended temperature range, said amplifier means including resistor means having a first resistive portion formed in the epitaxial layer and a second resistive portion having a constant temperature coefficient.
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Abstract
A linear Hall effect integrated circuit in which the output signal of a Hall element formed in an epitaxial layer is amplified by an amplifier circuit whose gain is determined by a resistor partially formed in the same epitaxial layer. A first amplifier stage configured as a voltage to current converter is connected through a current mirror to a second amplifier stage configured as a current to voltage converter. The current bias for the first amplifier stage is controlled by a resistor also partially formed in the epitaxial layer.
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Citations
16 Claims
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1. A temperature compensated integrated circuit Hall effect device comprising:
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a substrate having an epitaxial layer thereon; a Hall effect element formed in said epitaxial layer, said Hall effect element having first and second output terminals between which is produced a voltage difference indicative of the magnitude of an applied magnetic field; and amplifier means connected to the first and second output terminals of said Hall effect element for receiving a voltage difference produced in response to a magnetic field and producing an output voltage whose magnitude is substantially linearly related to the magnitude of the magnetic field over an extended temperature range, said amplifier means including resistor means having a first resistive portion formed in the epitaxial layer and a second resistive portion having a constant temperature coefficient. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A temperature compensated integrated circuit Hall effect device having a voltage supply terminal, a reference voltage terminal and an output terminal, the Hall effect device comprising:
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a substrate having an epitaxial layer thereon; a Hall effect element formed in said epitaxial layer, said Hall effect element being operable to produce a voltage difference between first and second terminals thereof when an electric current is caused to flow between third and fourth terminals thereof and said element is subjected to a magnetic field; a voltage supply conductor connected to the voltage supply terminal; a reference voltage conductor connected to the reference voltage terminal; first and second ideally identical amplifiers, each having first and second input terminals, an input offset adjustment terminal, a temperature tracking bias terminal and output terminal means, the first input terminals of the first and second amplifiers being connected to the first and second terminals respectively of said Hall effect element, the input offset adjustment terminals of said first and second amplifiers being connected to said voltage supply conductor through first and second input offset adjustment circuits respectively, the temperature tracking bias terminals of said first and second amplifiers being connected to said reference voltage conductor through bias resistor means including a first resistive portion formed in the epitaxial layer on said substrate, and the output terminal means of said first and second amplifiers being connected to said reference voltage conductor through output offset adjustment means including output offset adjustment resistors; a first gain control resistor connected between the second input terminals of said first and second amplifiers; a third amplifier having first and second input terminals, a null adjustment terminal, and an output terminal connected to the output terminal of the Hall effect device, the null adjustment terminal being connected to said voltage supply conductor and said reference voltage conductor through a voltage divider; a second gain control resistor connected between the first and second input terminals of said third amplifier, said second gain control resistor including a first resistive portion formed in the epitaxial layer on said substrate; and first and second current mirrors connecting the output terminal means of said first and second amplifiers to the first and second input terminals of said third amplifier respectively. - View Dependent Claims (14, 15, 16)
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Specification