US5451859A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Linear transconductors
Assignee: STMicroelectronics lnc USA
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Filing: 1993-03-15
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Granted: 1995-09-19
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Expires: 2013-03-15
Abstract
Abstract An integrated transconductor circuit in which the input transistor(s) passes a current across a reference resistor. This conventional arrangement produces current error terms of Vbe/R and Ib. According to the present invention, these terms are compensated by providing a compensation resistor which is matched to the first resistor, and a compensation transistor which is matched to the input transistor, interconnected to feed the appropriate current components to the output. For even better compensation, an additional transistor is optionally added to remove the effect of base current of the compensation transistor. In differential embodiments, the compensation resistor may be bridged or split. Zero, one, or more stages of current mirroring can optionally be used to provide the desired output.
Inventors
- 👤 Marc Ryat
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 03:21
CPC Classifications
H; H03; H03F; H03F3/00; H03F3/34; H03F3/343; G; G05; G05F; G05F3/00; G05F3/02; G05F3/08; G05F3/10; G05F3/16; G05F3/20; G05F3/26; G05F3/265; H03F2200/00; H03F2200/261
Claims Analysis
Total Claims: 43
Claim 1
Independent Claim
137 words
A transconductor integrated circuit, comprising: a connection for receiving an input voltage; a first bipolar transistor connected to be controlled by said input voltage, and to pass a first current through a reference first resistance accordingly: a second resistance, matched to said first resistance; and a second bipolar transistor, matched to said first transistor, and coupled to said second resistance; a current output terminal, which is operatively connected to provide a current which is directly proportional to the sum of: a current component equal to the collector current of said first transistor; a current component equal to the base current of said second transistor, and also equal to the base current of said first transistor; and a current component equal to the base-emitter voltage drop of said second transistor, divided by the value of said first resistance.
Claim 2
Dependent Claim
137 words
A transconductor integrated circuit, comprising: a connection for receiving an input voltage; a first bipolar transistor connected to be controlled by said input voltage, and to pass a first current through a reference first resistance accordingly: a second resistance, matched to said first resistance; and a second bipolar transistor, matched to said first transistor, and coupled to said second resistance; a current output terminal, which is operatively connected to provide a current which is directly proportional to the sum of: a current component equal to the collector current of said first transistor; a current component equal to the base current of said second transistor, and also equal to the base current of said first transistor; and a current component equal to the base-emitter voltage drop of said second transistor, divided by the value of said first resistance.
Claim 3
Dependent Claim
18 words
The integrated circuit of claim 1, wherein said second transistor is connected in series with said first transistor.
Claim 4
Dependent Claim
12 words
An integrated circuit comprising at least two transconductors according to claim 1.
Claim 5
Dependent Claim
29 words
The integrated circuit of claim 1, further comprising a current mirror connected to mirror the collector current of said first transistor into the collector current of said second transistor.
Claim 6
Dependent Claim
57 words
The integrated circuit of claim 1, further comprising a first current mirror connected to mirror the collector current of said first transistor into the collector current of said second transistor, and a second mirror connected to mirror the emitter current of said second transistor, together with current provided by said second resistance, to provide said output current.
Claim 7
Dependent Claim
59 words
The integrated circuit of claim 1, further comprising a first current mirror connected to mirror the collector current of said first transistor into the collector current of said second transistor, and a second mirror connected to mirror the emitter current of said second transistor, and to add in current provided by said second resistance, to provide said output current.
Claim 8
Dependent Claim
18 words
The integrated circuit of claim 1, further comprising at least one cascode transistor interposed in said output current.
Claim 9
Dependent Claim
20 words
The integrated circuit of claim 1, further comprising multiple mirrored transistors connected to provide multiple copies of said output current.
Claim 10
Dependent Claim
158 words
A transconductor integrated circuit, comprising: a first bipolar transistor having a base operatively connected to be controlled by an input voltage, and having collector and emitter connected to pass a first current through a reference first resistance accordingly: a second resistance, matched to said first resistance; and a second bipolar transistor, matched to said first transistor, and coupled to said second resistance; an additional transistor, coupled to said second resistance, and connected to compensate for base current of said second transistor; a current output terminal, which is operatively connected to provide a current which is directly proportional to the sum of: a current component equal to the collector current of said first transistor; a current component equal to the base current of said second transistor, and also equal to the base current of said first transistor; and a current component equal to the base-emitter voltage drop of said second transistor, divided by the value of said first resistance.
Claim 11
Dependent Claim
158 words
A transconductor integrated circuit, comprising: a first bipolar transistor having a base operatively connected to be controlled by an input voltage, and having collector and emitter connected to pass a first current through a reference first resistance accordingly: a second resistance, matched to said first resistance; and a second bipolar transistor, matched to said first transistor, and coupled to said second resistance; an additional transistor, coupled to said second resistance, and connected to compensate for base current of said second transistor; a current output terminal, which is operatively connected to provide a current which is directly proportional to the sum of: a current component equal to the collector current of said first transistor; a current component equal to the base current of said second transistor, and also equal to the base current of said first transistor; and a current component equal to the base-emitter voltage drop of said second transistor, divided by the value of said first resistance.
Claim 12
Dependent Claim
18 words
The integrated circuit of claim 9, wherein said second transistor is connected in series with said first transistor.
Claim 13
Dependent Claim
14 words
The integrated circuit of claim 9, wherein said first and second transistors are NPN.
Claim 14
Dependent Claim
19 words
The integrated circuit of claim 9, wherein said first and second transistors both have betas of at least 90.
Claim 15
Dependent Claim
12 words
An integrated circuit comprising at least two transconductors according to claim 9.
Claim 16
Dependent Claim
29 words
The integrated circuit of claim 9, further comprising a current mirror connected to mirror the collector current of said first transistor into the collector current of said second transistor.
Claim 17
Dependent Claim
57 words
The integrated circuit of claim 9, further comprising a first current mirror connected to mirror the collector current of said first transistor into the collector current of said second transistor, and a second mirror connected to mirror the emitter current of said second transistor, together with current provided by said second resistance, to provide said output current.
Claim 18
Dependent Claim
59 words
The integrated circuit of claim 9, further comprising a first current mirror connected to mirror the collector current of said first transistor into the collector current of said second transistor, and a second mirror connected to mirror the emitter current of said second transistor, and to add in current provided by said second resistance, to provide said output current.
Claim 19
Dependent Claim
18 words
The integrated circuit of claim 9, further comprising at least one cascode transistor interposed in said output current.
Claim 20
Dependent Claim
20 words
The integrated circuit of claim 9, further comprising multiple mirrored transistors connected to provide multiple copies of said output current.
Claim 21
Dependent Claim
160 words
A transconductor integrated circuit, comprising: first and second differentially connected stages, each comprising: a connection for receiving an input voltage; a first bipolar transistor connected to be controlled by said input voltage, and to pass a first current through a reference first resistance accordingly: a second resistance, matched to said first resistance; and a second bipolar transistor, matched to said first transistor, and coupled to said second resistance; a current output terminal, which is operatively connected to provide a current which is directly proportional to the sum of: a current component equal to the collector current of said first transistor; a current component equal to the base current of said second transistor, and also equal to the base current of said first transistor; and a current component equal to the base-emitter voltage drop of said second transistor, divided by the value of said first resistance; wherein said current outputs of said first and second stages provide a differential transconductor output.
Claim 22
Dependent Claim
160 words
A transconductor integrated circuit, comprising: first and second differentially connected stages, each comprising: a connection for receiving an input voltage; a first bipolar transistor connected to be controlled by said input voltage, and to pass a first current through a reference first resistance accordingly: a second resistance, matched to said first resistance; and a second bipolar transistor, matched to said first transistor, and coupled to said second resistance; a current output terminal, which is operatively connected to provide a current which is directly proportional to the sum of: a current component equal to the collector current of said first transistor; a current component equal to the base current of said second transistor, and also equal to the base current of said first transistor; and a current component equal to the base-emitter voltage drop of said second transistor, divided by the value of said first resistance; wherein said current outputs of said first and second stages provide a differential transconductor output.
Claim 23
Dependent Claim
18 words
The integrated circuit of claim 19, wherein said second transistor is connected in series with said first transistor.
Claim 24
Dependent Claim
14 words
The integrated circuit of claim 19, wherein said first and second transistors are NPN.
Claim 25
Dependent Claim
19 words
The integrated circuit of claim 19, wherein said first and second transistors both have betas of at least 90.
Claim 26
Dependent Claim
12 words
An integrated circuit comprising at least two transconductors according to claim 19.
Claim 27
Dependent Claim
29 words
The integrated circuit of claim 19, further comprising a current mirror connected to mirror the collector current of said first transistor into the collector current of said second transistor.
Claim 28
Dependent Claim
57 words
The integrated circuit of claim 19, further comprising a first current mirror connected to mirror the collector current of said first transistor into the collector current of said second transistor, and a second mirror connected to mirror the emitter current of said second transistor, together with current provided by said second resistance, to provide said output current.
Claim 29
Dependent Claim
59 words
The integrated circuit of claim 19, further comprising a first current mirror connected to mirror the collector current of said first transistor into the collector current of said second transistor, and a second mirror connected to mirror the emitter current of said second transistor, and to add in current provided by said second resistance, to provide said output current.
Claim 30
Dependent Claim
18 words
The integrated circuit of claim 19, further comprising at least one cascode transistor interposed in said output current.
Claim 31
Dependent Claim
20 words
The integrated circuit of claim 19, further comprising multiple mirrored transistors connected to provide multiple copies of said output current.
Claim 32
Dependent Claim
188 words
A transconductor integrated circuit, comprising: a first bipolar transistor having a base operatively connected to be controlled by an input voltage, and having collector and emitter connected to pass a first current through a reference first resistance accordingly: a current mirror, connected to mirror said first current to produce a mirrored current; a second bipolar transistor, matched to said first transistor, and connected to pass said mirrored current between emitter and collector thereof; a second resistance, matched to said first resistance, and connected between emitter and collector of said second transistor; and an additional transistor, coupled to said second resistance, and connected to compensate for base current of said second transistor; a current output terminal, which is operatively connected to provide a current which is directly proportional to the sum of: a current component equal to the collector current of said first transistor; a current component equal to the base current of said second transistor, and also equal to the base current of said first transistor; and a current component equal to the base-emitter voltage drop of said second transistor, divided by the value of said first resistance.
Claim 33
Dependent Claim
188 words
A transconductor integrated circuit, comprising: a first bipolar transistor having a base operatively connected to be controlled by an input voltage, and having collector and emitter connected to pass a first current through a reference first resistance accordingly: a current mirror, connected to mirror said first current to produce a mirrored current; a second bipolar transistor, matched to said first transistor, and connected to pass said mirrored current between emitter and collector thereof; a second resistance, matched to said first resistance, and connected between emitter and collector of said second transistor; and an additional transistor, coupled to said second resistance, and connected to compensate for base current of said second transistor; a current output terminal, which is operatively connected to provide a current which is directly proportional to the sum of: a current component equal to the collector current of said first transistor; a current component equal to the base current of said second transistor, and also equal to the base current of said first transistor; and a current component equal to the base-emitter voltage drop of said second transistor, divided by the value of said first resistance.
Claim 34
Dependent Claim
18 words
The integrated circuit of claim 29, wherein said second transistor is connected in series with said first transistor.
Claim 35
Dependent Claim
14 words
The integrated circuit of claim 29, wherein said first and second transistors are NPN.
Claim 36
Dependent Claim
19 words
The integrated circuit of claim 29, wherein said first and second transistors both have betas of at least 90.
Claim 37
Dependent Claim
12 words
An integrated circuit comprising at least two transconductors according to claim 29.
Claim 38
Dependent Claim
34 words
The integrated circuit of claim 29, further comprising a second mirror connected to mirror the emitter current of said second transistor, together with current provided by said second resistance, to provide said output current.
Claim 39
Dependent Claim
36 words
The integrated circuit of claim 29, further comprising a second mirror connected to mirror the emitter current of said second transistor, and to add in current provided by said second resistance, to provide said output current.
Claim 40
Dependent Claim
18 words
The integrated circuit of claim 29, further comprising at least one cascode transistor interposed in said output current.
Claim 41
Dependent Claim
20 words
The integrated circuit of claim 29, further comprising multiple mirrored transistors connected to provide multiple copies of said output current.
Claim 42
Independent Claim
199 words
A method for operating a transconductor integrated circuit, comprising the steps of: receiving an input voltage on the base of a first bipolar transistor, and passing a first current through a reference first resistance accordingly, to produce a collector current which is approximately equal to the input voltage divided by the value of said first resistance: driving a second bipolar transistor, which is matched to said first transistor, with a collector current which is equal to the collector current of said first transistor, while holding the base-emitter voltage of said second transistor equal to the base-emitter voltage of said first transistor, to produce a first compensation current component which is equal to the base current of said first transistor, and also to the base current of said second transistor; generating, in a second resistance which is matched to said first resistance, a current component corresponding to the Vbe drop of said first transistor divided by the resistance of said first resistance; and combining said first and second current compensation components with a component corresponding to said collector current, to accordingly provide a current output which very closely approximates the input voltage divided by the value of said first resistance.
Claim 43
Independent Claim
199 words
A method for operating a transconductor integrated circuit, comprising the steps of: receiving an input voltage on the base of a first bipolar transistor, and passing a first current through a reference first resistance accordingly, to produce a collector current which is approximately equal to the input voltage divided by the value of said first resistance: driving a second bipolar transistor, which is matched to said first transistor, with a collector current which is equal to the collector current of said first transistor, while holding the base-emitter voltage of said second transistor equal to the base-emitter voltage of said first transistor, to produce a first compensation current component which is equal to the base current of said first transistor, and also to the base current of said second transistor; generating, in a second resistance which is matched to said first resistance, a current component corresponding to the Vbe drop of said first transistor divided by the resistance of said first resistance; and combining said first and second current compensation components with a component corresponding to said collector current, to accordingly provide a current output which very closely approximates the input voltage divided by the value of said first resistance.
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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) | 1998-09-18 | 1999-03-20 | 1999-09-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-09-18 | 2003-03-20 | 2003-09-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-09-18 | 2007-03-20 | 2007-09-19 | $7700.00 | Window Closed / Lapsed |