Patent US4939442A successfully refreshed from Google Patents.
US4939442A
Expired / Lapsed
US
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Bandgap voltage reference and method with further temperature correction
Assignee: Texas Instruments Inc
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Filing: 1989-03-30
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Granted: 1990-07-03
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Expires: 2009-03-30
Abstract
Abstract A voltage reference circuit (26) provides a stable output reference voltage over a wide temperature range. A high temperature curvature correction circuit (36) is enabled at a first predetermined temperature to adjust the output voltage accordingly. A low temperature curvature correction circuit (38) is enabled at temperatures below a second predetermined temperature to similarly affect a output voltage. The preferred embodiment, the high and low curvature correction circuits (36, 38) are operable to vary the current through one or more resistors in a bandgap circuit (26) or other reference circuit.
Inventors
- 👤 Fernando D. Carvajal
- 👤 Thomas A. Schmidt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 16:30
CPC Classifications
G; G05; G05F; G05F3/00; G05F3/02; G05F3/08; G05F3/10; G05F3/16; G05F3/20; G05F3/30; Y; Y10; Y10S; Y10S323/00; Y10S323/907
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
136 words
A circuit for generating a stable reference voltage over a wide temperature range, comprising: a voltage generator for providing a relatively stable output voltage within a known temperature range, said generator including (i) first and second mismatched bipolar transistors, the emitters of said first and second bipolar transistors tied together, (ii) a first resistor connected between the bases of said first and second bipolar transistors, and (iii) a second resistor in series with said first resistor and passing said first current, said generator providing said relatively stable output voltage from current determined by said first resistor; and circuitry for adjusting said output voltage responsive to a predetermined temperature to maintain a stable output voltage, said circuitry providing current at through said second resistor and parallel said first resistor for temperatures outside of said known temperature range.
Claim 2
Dependent Claim
136 words
A circuit for generating a stable reference voltage over a wide temperature range, comprising: a voltage generator for providing a relatively stable output voltage within a known temperature range, said generator including (i) first and second mismatched bipolar transistors, the emitters of said first and second bipolar transistors tied together, (ii) a first resistor connected between the bases of said first and second bipolar transistors, and (iii) a second resistor in series with said first resistor and passing said first current, said generator providing said relatively stable output voltage from current determined by said first resistor; and circuitry for adjusting said output voltage responsive to a predetermined temperature to maintain a stable output voltage, said circuitry providing current at through said second resistor and parallel said first resistor for temperatures outside of said known temperature range.
Claim 3
Dependent Claim
14 words
The circuit of claim 1 wherein said voltage generator comprises a bandgap voltage reference.
Claim 4
Dependent Claim
31 words
The circuit of claim 1 wherein said adjusting circuitry comprises: a circuit for generating a temperature dependent voltage; and a circuit for generating a current responsive to said temperature dependent voltage.
Claim 5
Dependent Claim
15 words
The circuit of claim 3 wherein said circuit for generating a voltage comprises a resistor.
Claim 6
Dependent Claim
15 words
The circuit of claim 3 wherein said circuit for generating a current comprises a transistor.
Claim 7
Dependent Claim
20 words
The circuit of claim 1 wherein said voltage generator includes one or more resistors through which a current is driven.
Claim 8
Dependent Claim
31 words
The circuit of claim 6 wherein said adjusting circuitry comprises circuitry to adjust the current through one or more of said resistors such that the voltage across the resistors is varied.
Claim 9
Dependent Claim
39 words
The circuit of claim 1 wherein said adjusting circuitry comprises first adjusting circuitry to adjust the output voltage in response to a first temperature and second adjusting circuitry to adjust the output voltage in response to a second temperature.
Claim 10
Independent Claim
105 words
The method of generating a stable output voltage reference comprising the steps of: generating a relatively stable output voltage over a known temperature range by the use of emitter tied mismatched bipolar transistors with bases connected by a first resistor and with said relatively stable output voltage determined by a first current through said first resistor; detecting a predetermined temperature; and adjusting said output voltage in response to said temperature detection in order to provide a stable voltage reference by drawing a second current through a second resistor, said second resistor in series with said first resistor and said second resistor passing said first current.
Claim 11
Independent Claim
105 words
The method of generating a stable output voltage reference comprising the steps of: generating a relatively stable output voltage over a known temperature range by the use of emitter tied mismatched bipolar transistors with bases connected by a first resistor and with said relatively stable output voltage determined by a first current through said first resistor; detecting a predetermined temperature; and adjusting said output voltage in response to said temperature detection in order to provide a stable voltage reference by drawing a second current through a second resistor, said second resistor in series with said first resistor and said second resistor passing said first current.
Claim 12
Dependent Claim
21 words
The method of claim 9 wherein said detection step comprises: generating a temperature dependent voltage; and detecting a predetermined voltage level.
Claim 13
Dependent Claim
23 words
The method of claim 10 wherein said adjusting step comprises the step of enabling a transistor responsive to detecting said predetermined voltage level.
Claim 14
Dependent Claim
26 words
The method of claim 11 wherein said step of generating a relatively stable output voltage comprises the step of drawing current through one or more resistors.
Claim 15
Dependent Claim
26 words
The method of claim 12 wherein said adjusting step further comprises the step of adjusting the amount of current through one or more of said resistors.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-07-02 | 1994-01-01 | 1994-07-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-07-02 | 1998-01-01 | 1998-07-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-07-02 | 2002-01-01 | 2002-07-03 | $7700.00 | Window Closed / Lapsed |