US5289111A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Bandgap constant voltage circuit
Assignee: Rohm Co Ltd
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Filing: 1992-05-13
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Granted: 1994-02-22
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Expires: 2012-05-13
Abstract
Abstract A constant voltage circuit is to stabilize a constant voltage output with respect to a source voltage and produce the constant voltage output at a lower level of the source voltage. The constant voltage circuit is arranged to generate an output of constant voltage (constant voltage Vreg) by using a band-gap circuit (2), and comprises an error detecting circuit (4) for detecting an error voltage between the constant voltage generated by the band-gap circuit and a setting value, an output circuit (6) for receiving a current indicative of the error voltage from the error detecting circuit, generating a current depending on the received current, and feeding the generated current back to the band-gap circuit, and an initiating circuit (8) for supplying an initiation current to the band-gap circuit at the time of raising a source voltage.
Inventors
- 👤 Yasuhiko Tsuji
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 08:03
CPC Classifications
G; G05; G05F; G05F3/00; G05F3/02; G05F3/08; G05F3/10; G05F3/16; G05F3/20; G05F3/22; G05F3/222; G05F3/227; H; H03; H03K; H03K19/00; G05F3/30; Y; Y10; Y10S; Y10S323/00; Y10S323/907
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
179 words
A constant voltage circuit for generating an output of constant voltage by using a band-gap circuit generating a constant voltage, comprising: an error detecting circuit for detecting an error voltage between the constant voltage generated by said band-gap circuit and a reference voltage value, generating a current representing the error voltage, an output circuit for receiving said current indicative of said error voltage from said error detecting circuit, generating a current depending on the received current, and feeding said generated current back to said band-gap circuit, an initiating circuit for supplying an initiation current to said band-gap circuit at the time of raising a source voltage applied to said band-gap circuit, wherein said initiating circuit includes a bias circuit for receiving said source voltage and generating a constant bias voltage by a plurality of diodes, a first transistor conducted by said bias circuit at the time of initiation, and a second transistor for receiving a conduction current of said first transistor or a current produced by said output circuit and supplying an operating current to said error detecting circuit.
Claim 2
Dependent Claim
179 words
A constant voltage circuit for generating an output of constant voltage by using a band-gap circuit generating a constant voltage, comprising: an error detecting circuit for detecting an error voltage between the constant voltage generated by said band-gap circuit and a reference voltage value, generating a current representing the error voltage, an output circuit for receiving said current indicative of said error voltage from said error detecting circuit, generating a current depending on the received current, and feeding said generated current back to said band-gap circuit, an initiating circuit for supplying an initiation current to said band-gap circuit at the time of raising a source voltage applied to said band-gap circuit, wherein said initiating circuit includes a bias circuit for receiving said source voltage and generating a constant bias voltage by a plurality of diodes, a first transistor conducted by said bias circuit at the time of initiation, and a second transistor for receiving a conduction current of said first transistor or a current produced by said output circuit and supplying an operating current to said error detecting circuit.
Claim 3
Dependent Claim
28 words
A constant voltage circuit according to claim 1, wherein said error detecting circuit, said output circuit, and said initiating circuit are mounted on a single semiconductor integrated circuit.
Claim 4
Dependent Claim
78 words
A constant voltage circuit according to claim 1, wherein said band-gap circuit comprises a first serial circuit including a resistor and a diode which are connected between a constant voltage line and a reference potential point, and a second serial circuit including a transistor, a diode and a resistor, and a voltage at the junction between the resistor and the diode of said first serial circuit applied to a base of the transistor of said second serial circuit.
Claim 5
Dependent Claim
54 words
A constant voltage circuit according to claim 1, wherein said output circuit comprises: a third transistor receiving at its base an error current from said error detecting circuit, and a fourth transistor receiving its base current through said third transistor and feeding a current depending on said error current back to said band-gap circuit.
Claim 6
Dependent Claim
45 words
A constant voltage circuit according to claim 3, wherein said error detecting circuit comprises a differential circuit for outputting a differential voltage between a base voltage and a collector voltage of the transistor in said band-gap circuit on the side of said second serial circuit.
Claim 7
Dependent Claim
89 words
A constant voltage circuit according to claim 3, wherein said error detecting circuit includes a transistor differential circuit for outputting a differential voltage between a base voltage and a collector voltage of the transistor in said band-gap circuit on the side of said second serial circuit, and a serial circuit including a resistor, a diode, and a transistor having its base and collector connected in common to each other and connected between a collector of one of two transistors, which constitute said transistor differential circuit, and a power source.
Claim 8
Dependent Claim
55 words
A constant voltage circuit according to claim 6, wherein said initiating circuit is formed by connecting a transistor between a source line and said constant voltage line, and connecting a base of said latter transistor to the common base and collector side of said transistor which is connected to said transistor differential circuit in series.
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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) | 1997-02-21 | 1997-08-23 | 1998-02-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-02-21 | 2001-08-23 | 2002-02-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-02-21 | 2005-08-23 | 2006-02-22 | $7700.00 | Window Closed / Lapsed |