US5115206A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Merged differential amplifier and current source
Assignee: Philips North America LLC
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Filing: 1990-11-08
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Granted: 1992-05-19
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Expires: 2010-11-08
Abstract
Abstract The tail current of a differential transistor pair (12 and 14) is controlled by a feed-back means (40) that couples the pair's tail node (16) to the control input of each transistor for controlling a biasing current through each transistor. The control input of each transistor further receives an input signal in addition to an output signal of the feed-back means. As a result, the circuit has a stable and accurate tail current, and in addition is suitable for a low-voltage supply or for high-current operation.
Inventors
- 👤 William D. Mack
- 👤 Daniel J. Linebarger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 06:36
CPC Classifications
H; H03; H03F; H03F3/00; H03F3/45; H03F3/45071; H03F3/45076; H03F3/4508; H03F3/45085; H03F3/45479; H03F3/45484; H03F3/45488; H03F3/45533; H03F3/45538; H03F2203/00; H03F2203/45; H03F2203/45484; H03F2203/45498; H03F2203/45612
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
154 words
An electronic circuit comprising: first and second signal input nodes for receiving first and second input signals; first and second active devices each having (i) a main current path and (ii) a device input coupled to a respective one of the signal input nodes for control of the main current path; a current source coupled to the main current paths via a tail node for biasing the active devices; and feed-back means that provides a common-mode coupling from the tail node to each device input for controlling a bias current through each main current path in response to a control signal, different from the first and second input signals, applied to the feed-back means, wherein the feed-back means includes: a differential amplifier with a first input for receiving the control signal, a second input coupled to the tail node, and an output, and a resistive coupling between the amplifier's output and each device input.
Claim 2
Dependent Claim
154 words
An electronic circuit comprising: first and second signal input nodes for receiving first and second input signals; first and second active devices each having (i) a main current path and (ii) a device input coupled to a respective one of the signal input nodes for control of the main current path; a current source coupled to the main current paths via a tail node for biasing the active devices; and feed-back means that provides a common-mode coupling from the tail node to each device input for controlling a bias current through each main current path in response to a control signal, different from the first and second input signals, applied to the feed-back means, wherein the feed-back means includes: a differential amplifier with a first input for receiving the control signal, a second input coupled to the tail node, and an output, and a resistive coupling between the amplifier's output and each device input.
Claim 3
Dependent Claim
25 words
A circuit as in claim 1 wherein each signal input node is coupled to the device input of the respective active device via a resistor.
Claim 4
Dependent Claim
177 words
An electronic circuit comprising: first and second signal input nodes for receiving first and second input signals; first and second active devices each having (i) a main current path and (ii) a device input coupled to a respective one of the signal input nodes for control of the main current path; a current source coupled to the main current paths via a tail node for biasing the active devices; and feed-back means that provides a common-mode coupling from the tail node to each device input for controlling a bias current through each main current path in response to a control signal, different from the first and second input signals, applied to the feed-back means, wherein the feed-back means includes: a differential amplifier with a first input for receiving the control signal, a second input coupled to the tail node, and an output for providing an amplifier output signal, and first and second signal pre-amplifiers respectively responsive to the first and second input signals and responsive to amplifier output signal for controlling the first and second active devices.
Claim 5
Dependent Claim
177 words
An electronic circuit comprising: first and second signal input nodes for receiving first and second input signals; first and second active devices each having (i) a main current path and (ii) a device input coupled to a respective one of the signal input nodes for control of the main current path; a current source coupled to the main current paths via a tail node for biasing the active devices; and feed-back means that provides a common-mode coupling from the tail node to each device input for controlling a bias current through each main current path in response to a control signal, different from the first and second input signals, applied to the feed-back means, wherein the feed-back means includes: a differential amplifier with a first input for receiving the control signal, a second input coupled to the tail node, and an output for providing an amplifier output signal, and first and second signal pre-amplifiers respectively responsive to the first and second input signals and responsive to amplifier output signal for controlling the first and second active devices.
Claim 6
Dependent Claim
49 words
A circuit as in claim 3 wherein each signal pre-amplifier has (i) a first input, coupled to the amplifier output for receiving the amplifier output signal and (ii) a further input coupled to a respective one of the first and second input nodes for receiving the associated input signal.
Claim 7
Dependent Claim
84 words
A circuit as in claim 4 wherein each pre-amplifier includes: a third active device with a third device input coupled to the further input and with a third main current path, and a fourth active device with a fourth device input coupled to the output and with a fourth main current path connected to the third main current path via an intermediate node, wherein the intermediate node is coupled to the device input of a respective one of the first and second active devices.
Claim 8
Dependent Claim
13 words
A circuit as in claim 1 wherein the current source includes a resistor.
Claim 9
Dependent Claim
13 words
A circuit as in claim 3 wherein the current source includes a resistor.
Claim 10
Dependent Claim
30 words
A circuit as in claim 1 wherein at least one further active device has its main current path connected to the tail node and is controlled by the feed-back means.
Claim 11
Dependent Claim
30 words
A circuit as in claim 3 wherein at least one further active device has its main current path connected to the tail node and is controlled by the feed-back means.
Claim 12
Dependent Claim
123 words
A circuit as in claim 4 wherein: each of the first and second active devices includes a bipolar transistor having an emitter coupled to the tail node via a respective resistor; and each signal pre-amplifier includes: i) a third bipolar transistor with a base coupled to a respective one of the signal input nodes, ii)a further current source coupled to an emitter of the third bipolar transistor through a further resistor and having a control terminal coupled to the output of the differential amplifier, and iii) an emitter follower with a fourth bipolar transistor for coupling a further node between the further resistor and the further current source to the device input of a respective one of the first and second active devices.
Claim 13
Dependent Claim
13 words
A circuit as in claim 1 wherein each active device includes a transistor.
Claim 14
Dependent Claim
13 words
A circuit as in claim 3 wherein each active device includes a transistor.
Claim 15
Dependent Claim
13 words
A circuit as in claim 5 wherein each active device includes a transistor.
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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) | 1995-05-19 | 1995-11-18 | 1996-05-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-05-19 | 1999-11-18 | 2000-05-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-05-19 | 2003-11-18 | 2004-05-19 | $7700.00 | Window Closed / Lapsed |