EP0064126A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
A differential amplifier
Assignee: International Business Machines Corp
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Filing: 1982-01-19
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Granted: —
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Expires: 2002-01-19
Abstract
Abstract This invention relates to a differential amplifier which is compensated for temperature and power supply variations. The amplifier includes a differential pair of transistors (11, 12) with resistors (22, 23) in the collector circuits and a current source transistor (25) in the emitter circuits. The base bias signal for the current source transistor (25) is supplied from a correction circuit (36, 48, 54) which includes at least one transistor (54) located proximate the differential transistor. The correction circuit provides a temperature compensated and power supply variation compensated signal to correct the amplifier for these variations.
Inventors
- 👤 Fernando Castro
- 👤 Franklin Camille Fountain
- 👤 Julian Lewkowicz
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 22:36
CPC Classifications
H; H03; H03F; H03F3/00; H03F3/45; H03F3/45071; H03F3/45076; H03F3/4508; H03F3/45085; H03F2203/00; H03F2203/45; H03F2203/45456; H03F2203/45476; H03F2203/45508; H03F2203/45702
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
128 words
A differential amplifier comprising a pair of transistors (11, 12) connected in differential arrangement with resistors (22, 23) in the collector circuits and a current source transistor (25) connected in the emitter circuit (13, 14, 15) between a high voltage supply and a reference node (38), characterised in that the amplifier further includes correction circuit means (36, 48, 54) interconnected between the high voltage supply and the base of the current source transistor (25), said correction circuit means including an amplifier transistor (54) arranged proximate to the differential pair of transistors, for providing a correction bias signal to the base of said current source transistor (25) whereby a high-gain output is obtained from the differential pair of transistors that is compensated for temperature variations and power supply variations.
Claim 2
Dependent Claim
128 words
A differential amplifier comprising a pair of transistors (11, 12) connected in differential arrangement with resistors (22, 23) in the collector circuits and a current source transistor (25) connected in the emitter circuit (13, 14, 15) between a high voltage supply and a reference node (38), characterised in that the amplifier further includes correction circuit means (36, 48, 54) interconnected between the high voltage supply and the base of the current source transistor (25), said correction circuit means including an amplifier transistor (54) arranged proximate to the differential pair of transistors, for providing a correction bias signal to the base of said current source transistor (25) whereby a high-gain output is obtained from the differential pair of transistors that is compensated for temperature variations and power supply variations.
Claim 3
Dependent Claim
139 words
An amplifier as claimed in Claim 1, wherein said correction circuit includes a first circuit branch having a transistor connected between the high voltage supply and a reference circuit and a second branch including a second transistor, similarly connected, but having a resistor of predetermined size in its emitter circuit whereby a proportional current flow is established between the transistors, the transistor in the second branch being proximate to the differential transistor pair, and circuit means for mirroring the current flow through the second branch transistor into a third branch including a third transistor having a large resistor in its emitter circuit whereby the collector-to-base voltage of the third transistor branch is compensated for temperature variations and power source variations, the current flow through said third transistor being used as a base input signal to the current source transistor.
Claim 4
Dependent Claim
22 words
An amplifier as claimed in Claim 2, wherein the first, second and third transistors are all located proximate to the differential transistors.
Claim 5
Dependent Claim
39 words
An amplifier as claimed in Claim 2 or 3, wherein the ratio of resistance of the second circuit branch to the first circuit branch is sufficiently high to cause a ratio of about 100:1 in the respective branch currents.
Claim 6
Dependent Claim
27 words
An amplifier as claimed in Claim 2, 3 or 4, wherein each circuit branch includes an additional transistor in the collector circuit of the respective branch transistor.
Claim 7
Dependent Claim
44 words
An amplifier as claimed in Claim 5, further including a fourth circuit branch comprising two transistors connected in series between a reference voltage and ground, the bases of the transistors being connected, respectively, to the bases of the transistors of the first circuit branch.
References Cited (Backward Citations)
No citation records indexed.
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