US5206550A
Expired / Lapsed
US
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Amplifier with actively clamped load
Assignee: Texas Instruments Inc
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Filing: 1991-06-20
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Granted: 1993-04-27
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Expires: 2011-06-20
Abstract
Abstract An amplifier is arranged with an actively clamped load. In a differential amplifier, a pair of emitter-coupled transistors has loads connected between the collectors and a voltage supply. Separate clamping transistors have their collector-emitter paths connected across respective ones of the loads. A clamping control circuit, responsive to an input signal, produces a variable control signal to clamp output signal swings across the loads. A similar clamping control circuit can be used with a single-ended amplifier. Such an amplifier having an actively clamped load is useful in sense amplifier circuit arrangements in semiconductor memory arrangements used in data processing systems.
Inventors
- 👤 Aswin N. Mehta
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 00:27
CPC Classifications
H; H03; H03F; H03F3/00; H03F3/45; H03F3/45071; H03F3/45076; H03F3/4508; H03F3/45174; H03F3/45085; H03F3/45179; H03F3/72; H03K; H03K5/00; H03K5/01; H03K5/02; H03K5/22; H03K5/24; H03K5/2409; H03K5/2418; H03F2200/00; H03F2200/219; H03F2200/285; H03F2200/525; H03F2203/00; H03F2203/45; H03F2203/45108; H03F2203/45144; H03F2203/45158; H03F2203/45178; H03F2203/45202; H03F2203/45466; H03F2203/45471; H03F2203/45506; H03F2203/45561; H03F2203/45578; H03F2203/45612; H03F2203/45636; H03F2203/45641; H03F2203/45702
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
108 words
A differential amplifier comprising: first and second emitter-coupled transistors; a current source connected between the emitters of the first and second emitter-coupled transistors and a reference potential; first and second loads are connected between the respective collector electrodes of the first and second emitter-coupled transistors and a voltage supply; first and second clamping transistors, each has its collector-emitter path connected across a respective one of the loads; and a clamping control circuit, responsive to an input signal, for producing and applying to base electrodes of the first and second clamping transistors variable control signals to clamp output signal swings at various levels across the first and second loads.
Claim 2
Dependent Claim
108 words
A differential amplifier comprising: first and second emitter-coupled transistors; a current source connected between the emitters of the first and second emitter-coupled transistors and a reference potential; first and second loads are connected between the respective collector electrodes of the first and second emitter-coupled transistors and a voltage supply; first and second clamping transistors, each has its collector-emitter path connected across a respective one of the loads; and a clamping control circuit, responsive to an input signal, for producing and applying to base electrodes of the first and second clamping transistors variable control signals to clamp output signal swings at various levels across the first and second loads.
Claim 3
Dependent Claim
48 words
A differential amplifier, in accordance with claim 1, wherein the clamping control circuit comprises first and second voltage divider circuits; and connections for applying to control electrodes of the first and second clamping transistors, respectively, voltages intermediate the end voltages of the first and second voltage divider circuits.
Claim 4
Dependent Claim
48 words
A differential amplifier, in accordance with claim 1, wherein the clamping control circuit comprises first and second voltage shifter circuits; and connections for applying to control electrodes of the first and second clamping transistors, respectively, voltages intermediate the end voltages of the first and second voltage shifter circuits.
Claim 5
Dependent Claim
72 words
A differential amplifier, in accordance with claim 3, wherein the clamping control circuit further comprises: a diode connected between each input terminal of the differential amplifier and a control terminal of the respective one of the first or second clamping transistors; and plural diodes connected in a series circuit between each input terminal of the differential amplifier and the control terminal of the respective one of the first or second emitter-coupled transistors.
Claim 6
Dependent Claim
22 words
A differential amplifier, in accordance with claim 1, wherein the control signals change with the D.C. voltage level of the input signal.
Claim 7
Dependent Claim
20 words
A differential amplifier, in accordance with claim 1, wherein the control signals vary with the magnitude of the input signal.
Claim 8
Dependent Claim
21 words
A differential amplifier, in accordance with claim 6, wherein the control signals change with the D.C. level of the input signal.
Claim 9
Dependent Claim
26 words
A differential amplifier, in accordance with claim 7, wherein output signal swings are clamped at different levels in response to the differences in the control signals.
Claim 10
Dependent Claim
32 words
A differential amplifier, in accordance with claim 8, wherein output signal swings are clamped to different levels in response to changes in the D.C. level and the magnitude of the input signal.
Claim 11
Dependent Claim
18 words
A differential amplifier, in accordance with claim 1, wherein the first and second transistors are a matched pair.
Claim 12
Dependent Claim
90 words
An amplifier comprising: a first transistor having an emitter electrode coupled to a reference potential; a load connected between a collector electrode of the first transistor and a voltage supply; a clamping transistor having a collector-emitter path connected across the load; and a clamping control circuit, responsive to a D.C. voltage level and to a magnitude of an input control signal, for producing a variable magnitude control signal, applied to a gate electrode of the clamping transistor, to cause signal swings to be clamped at various levels across the load.
Claim 13
Dependent Claim
90 words
An amplifier comprising: a first transistor having an emitter electrode coupled to a reference potential; a load connected between a collector electrode of the first transistor and a voltage supply; a clamping transistor having a collector-emitter path connected across the load; and a clamping control circuit, responsive to a D.C. voltage level and to a magnitude of an input control signal, for producing a variable magnitude control signal, applied to a gate electrode of the clamping transistor, to cause signal swings to be clamped at various levels across the load.
Claim 14
Dependent Claim
40 words
An amplifier, in accordance with claim 11, wherein the clamping control circuit comprises: a voltage divider circuit; and a connection for applying to a control electrode of the clamping transistor voltage intermediate the end voltages of the voltage divider circuit.
Claim 15
Dependent Claim
41 words
An amplifier, in accordance with claim 11, wherein the clamping control circuit comprises: a voltage shifter circuit; and a connection for applying to a control electrode of the clamping transistor a voltage intermediate the end voltages of the voltage shifter circuit.
Claim 16
Dependent Claim
55 words
An amplifier, in accordance with claim 13, wherein the clamping control circuit further comprises: a diode connected between an input terminal of the amplifier and the control terminal of the clamping transistor; and plural diodes connected in a series circuit between the input terminal of the amplifier and the control terminal of the first transistor.
Claim 17
Dependent Claim
20 words
An amplifier, in accordance with claim 11, wherein the control signal changes with a D.C. level of the input signal.
Claim 18
Dependent Claim
18 words
An amplifier, in accordance with claim 11, wherein the control signal varies with magnitude of the input signal.
Claim 19
Dependent Claim
20 words
An amplifier, in accordance with claim 16, wherein the control signal changes with a D.C. level of the input signal.
Claim 20
Dependent Claim
25 words
An amplifier, in accordance with claim 17, wherein output signal swings are clamped to the various levels in response to differences in the control signal.
Claim 21
Dependent Claim
30 words
An amplifier, in accordance with claim 18, wherein output signal swings are clamped to the various levels in response to the D.C. level and the magnitude of the input signal.
References Cited (Backward Citations)
JPS60117312A
Cited
JPH02150116A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-04-26 | 1996-10-26 | 1997-04-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-04-26 | 2000-10-26 | 2001-04-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-04-26 | 2004-10-26 | 2005-04-27 | $7700.00 | Window Closed / Lapsed |