US3816766A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Integrated circuit with hall cell
Assignee: Allegro Microsystems LLC
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Filing: 1973-01-29
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Granted: 1974-06-11
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Expires: 1993-01-29
Abstract
Abstract Described is an integrated circuit comprised of a hall cell, a differential amplifier and a current source; that operates as a sensitive magnetic-field-to-voltage transducer being essentially independent of ambient temperature changes.
Inventors
- 👤 R Anselmo
- 👤 M Oppenheimer
- 👤 R Genesi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 14:24
CPC Classifications
H; H10; H10B; H10B61/00; G; G01; G01R; G01R33/00; G01R33/02; G01R33/06; G01R33/07; H10N; H10N59/00
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
263 words
A temperature-stabilized integrated-circuit magnetic-field to electric-signal transducer comprising: a. a semiconductor body of silicon having formed on a portion thereof an epitaxial layer; b. a hall cell formed of said epitaxial layer material having at opposite ends two main contacts lying in a main axis thereof and having at other opposite sides two sensing contacts lying in a second major axis that is at right angles to said main axis; c. a differential amplifier being formed in said epitaxial layer, comprising a pair of planar transistors, the bases of which are connected to said sensing contacts, and a pair of collector resistors formed of said epitaxial material, the differential output points of said amplifier corresponding to the collectors of said pair of transistors, so that the temperature coefficient of resistance characterizing said epitaxial layer material determines the sensitivity of said hall cell as well as substantially determining the temperature coefficient of gain of said amplifier; and d. a current source circuit formed in said epitaxial layer, and being connected to the emitters of said pair of amplifier transistors in order to regulate the sum of the collector currents in said pair of transistors, said current source circuit comprising two equal geometry planar transistors having their bases interconnected and their emitters interconnected in normal current source fashion, and a series reference-current circuit composed of a resistor and one or more diode connected transistors, said one or more diode connected transistors thus being capable of further determining the temperature coefficient of gain of said amplifier and thus contributing to the temperature stabilization of said transducer.
Claim 2
Dependent Claim
263 words
A temperature-stabilized integrated-circuit magnetic-field to electric-signal transducer comprising: a. a semiconductor body of silicon having formed on a portion thereof an epitaxial layer; b. a hall cell formed of said epitaxial layer material having at opposite ends two main contacts lying in a main axis thereof and having at other opposite sides two sensing contacts lying in a second major axis that is at right angles to said main axis; c. a differential amplifier being formed in said epitaxial layer, comprising a pair of planar transistors, the bases of which are connected to said sensing contacts, and a pair of collector resistors formed of said epitaxial material, the differential output points of said amplifier corresponding to the collectors of said pair of transistors, so that the temperature coefficient of resistance characterizing said epitaxial layer material determines the sensitivity of said hall cell as well as substantially determining the temperature coefficient of gain of said amplifier; and d. a current source circuit formed in said epitaxial layer, and being connected to the emitters of said pair of amplifier transistors in order to regulate the sum of the collector currents in said pair of transistors, said current source circuit comprising two equal geometry planar transistors having their bases interconnected and their emitters interconnected in normal current source fashion, and a series reference-current circuit composed of a resistor and one or more diode connected transistors, said one or more diode connected transistors thus being capable of further determining the temperature coefficient of gain of said amplifier and thus contributing to the temperature stabilization of said transducer.
Claim 3
Dependent Claim
39 words
The transducer of claim 1 wherein said connection between said current source and said emitters of said pair of amplifier transistors is accomplished through two emitter resistors having been formed in said layer by a normal base diffusion step.
Claim 4
Dependent Claim
138 words
The transducer of claim 1 further comprising a schmitt trigger circuit means being formed in said body wherein said output of said amplifier is connected to the input terminals of said schmitt trigger circuit, for the purpose of providing a binary output such that when the strength of a portion of a magnetic field being orthogonal to said axes is increasing and exceeds a first predetermined value, the output of said schmitt trigger circuit changes from a first voltage level to a second voltage level, and when said strength of said portion of said magnetic field is decreasing and falls below a second predetermined value, the output of said schmitt trigger circuit changes from said second voltage level to said first voltage level, said second predetermined value of magnetic field strength being less than said first predetermined value.
Claim 5
Dependent Claim
55 words
The transducer of claim 1 further comprising a d.c. electrical energy source consisting of a conventional voltage regulator circuit formed within said body, and connective provisions for supplying electrical energy to said regulator from a source external to said transducer, said regulated voltage being connected to said hall cell, said amplifier and said current source.
Claim 6
Dependent Claim
265 words
A temperature-stabilized integrated-circuit magnetic-field to electric-signal transducer comprising: a. a semiconductor body of silicon having formed on a portion thereof an epitaxial layer of about 1 ohm-cm. and having a temperature coefficient of resistance of about +7,000 ppm; b. a hall cell formed of said epitaxial layer material having at opposite ends two main contacts lying in a main axis thereof and having at other opposite sides two sensing contacts lying in a second major axis that is at right angles to said main axis; c. a differential amplifier being formed in said epitaxial layer, comprising a pair of planar transistors, the bases of which are connected to said sensing contacts, and a pair of collector resistors formed of said epitaxial material, the differential output points of said amplifier corresponding to the collectors of said pair of transistors, so that the temperature coefficient of resistance characterizing said epitaxial layer material determines the sensitivity of said hall cell as well a substantially determining the temperature coefficient of gain of said amplifier; and d. a current source circuit formed in said epitaxial layer, and being connected to said pair of emitter resistors in order to regulate the sum of the collector currents in said pair of transistors, said current source comprising two equal geometry planar transistors having bases interconnected and emitters interconnected in normal current source fashion, and a reference current circuit having a series resistor, said series resistor and said pair of emitter resistors having been formed by a normal ion implantation step, and having a temperature coefficient of resistance on the order of +200 ppm.
Claim 7
Dependent Claim
265 words
A temperature-stabilized integrated-circuit magnetic-field to electric-signal transducer comprising: a. a semiconductor body of silicon having formed on a portion thereof an epitaxial layer of about 1 ohm-cm. and having a temperature coefficient of resistance of about +7,000 ppm; b. a hall cell formed of said epitaxial layer material having at opposite ends two main contacts lying in a main axis thereof and having at other opposite sides two sensing contacts lying in a second major axis that is at right angles to said main axis; c. a differential amplifier being formed in said epitaxial layer, comprising a pair of planar transistors, the bases of which are connected to said sensing contacts, and a pair of collector resistors formed of said epitaxial material, the differential output points of said amplifier corresponding to the collectors of said pair of transistors, so that the temperature coefficient of resistance characterizing said epitaxial layer material determines the sensitivity of said hall cell as well a substantially determining the temperature coefficient of gain of said amplifier; and d. a current source circuit formed in said epitaxial layer, and being connected to said pair of emitter resistors in order to regulate the sum of the collector currents in said pair of transistors, said current source comprising two equal geometry planar transistors having bases interconnected and emitters interconnected in normal current source fashion, and a reference current circuit having a series resistor, said series resistor and said pair of emitter resistors having been formed by a normal ion implantation step, and having a temperature coefficient of resistance on the order of +200 ppm.
Claim 8
Dependent Claim
138 words
The transducer of claim 5 further comprising a schmitt trigger circuit means being formed in said body wherein said output of said amplifier is connected to the input terminals of said schmitt trigger circuit, for the purpose of providing a binary output such that when the strength of a portion of a magnetic field being orthogonal to said axes is increasing and exceeds a first predetermined value, the output of said schmitt trigger circuit changes from a first voltage level to a second voltage level, and when said strength of said portion of said magnetic field is decreasing and falls below a second predetermined value, the output of said schmitt trigger circuit changes from said second voltage level to said first voltage level, said second predetermined value of magnetic field strength being less than said first predetermined value.
Claim 9
Dependent Claim
55 words
The transducer of claim 5 further comprising a d.c. electrical energy source consisting of a conventional voltage regulator circuit formed within said body, and connective provisions for supplying electrical energy to said regulator from a source external to said transducer, said regulated voltage being connected to said hall cell, said amplifier and said current source.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-06-10 | 1977-12-10 | 1978-06-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-10 | 1981-12-10 | 1982-06-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-10 | 1985-12-10 | 1986-06-11 | $7700.00 | Window Closed / Lapsed |