Patent EP0507388A2 successfully refreshed from Google Patents.
EP0507388A2
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Differential amplifier with signal-dependent quiescent current control
Assignee: Koninklijke Philips NV
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Filing: 1992-03-27
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Granted: —
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Expires: 2012-03-27
Abstract
Abstract Differential amplifier with signal-dependent quiescent current control, comprising: a first (T₁) and a second (T₂) transistor of the same conductivity type for conducting a first (I₁) and a second (I₂) current respectively, the two transistors comprising each a control electrode coupled to a first (6) and a second (8) input terminal respectively, for feeding an input signal, a first main electrode coupled to a common terminal (3), converting means (10A, 10B) for converting the first and the second current to a measuring current in response to the first and the second current, comparing means comprising a control output terminal (11) for presenting a signal (I S ) in response to the difference between the measuring current and the reference current (2I Q ) of a reference current source (14), a controllable quiescent current source (4) coupled to the common terminal (3) for presenting a quiescent current (I O ) at the common terminal and having, coupled to the control output terminal (11), a control input (5) for controlling the quiescent current (I₀), whilst the converting means comprise: a first/second current generator (10A/10B) for generating a first/second derived current (I A /I B ) which decreases if the first second current (I₁/I₂) increases and vice versa , combining means (11) for generating the measuring current by adding together the first (I A ) and second (I B ) derived currents. Due to the inverse characteristic of the first/second current generator, the measuring current will be increasingly more dominated by the smaller of the first and second currents in the event of an increasing input signal, so that the minimum value of the smaller current will be determined by the reference current. Generating the first and second derived currents and combining them to the measuring current is a continuous process and can therefore react fast to amplitude variations in the first and second currents.
Inventors
- 👤 Pieter Gerrit Blanken
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 18:59
CPC Classifications
H; H03; H03F; H03F3/00; H03F3/45; H03F3/45071; H03F3/45076; H03F3/4508; H03F3/45085; H03F3/45479; H03F3/45484; H03F3/45547; H03F3/45551; H03F3/4556; H03F2203/00; H03F2203/45; H03F2203/45092; H03F2203/45112; H03F2203/45258; H03F2203/45392; H03F2203/45466; H03F2203/45471; H03F2203/45584
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
280 words
Differential amplifier with signal-dependent quiescent current control, comprising: - a first and a second input terminal for feeding an input signal, - a first and a second output terminal for presenting an output signal, - a common terminal, - a first and a second transistor of the same conductivity type for conducting a first and a second current respectively, the two transistors comprising each a control electrode coupled to the first and the second input terminal respectively, a first main electrode coupled to the common terminal and a second main electrode coupled to the first and the second output terminal respectively, - converting means for converting the first and the second current to a measuring current in response to, in essence, the smaller of the first and the second current, - comparing means comprising a control output terminal for presenting a signal in response to the difference between the measuring current and the reference current of a reference current source, - a controllable quiescent current source coupled to the common terminal for presenting a quiescent current at the common terminal and having a control input for controlling the quiescent current, - coupling means for coupling the control output terminal of the comparing means to the control input of the quiescent current source, characterized in that the converting means comprise: - a first current generator for generating a first derived current which decreases if the first current increases and vice versa , - a second current generator for generating a second derived current which decreases if the second current increases and vice versa , - combining means for generating the measuring current by adding together the first and second derived currents.
Claim 2
Dependent Claim
82 words
Differential amplifier as claimed in Claim 1, characterized in that the first and the second current generator respectively, both comprise: - a measuring transistor of a conductivity type opposite to that of the first and second transistors, comprising a second main electrode coupled to the control output terminal, a control electrode coupled to the control electrode of the first or second transistor respectively, and a first main electrode coupled to the first main electrode of the first and the second transistor respectively.
Claim 3
Dependent Claim
200 words
Differential amplifier as claimed in Claim 2, characterized in that the first main electrode of the measuring transistor is connected to the first main electrode of the first or second transistor respectively, and in that the first and the second current generator respectively, further include: - a third transistor of the same conductivity type as that of the first transistor, comprising a control electrode connected to the control electrode of the first or second transistor respectively, comprising a second main electrode coupled to a first supply terminal and comprising a first main electrode, - a fourth transistor of a conductivity type opposite to that of the first transistor, comprising a control electrode, a first main electrode and a second main electrode, in which the first main electrode of the fourth transistor is connected to the first main electrode of the third transistor, the control electrode of the fourth transistor is connected to the control electrode of the measuring transistor, whilst the control electrode and the second main electrode of the fourth transistor are intercoupled at least as regards AC voltage, - a bias current source coupled between the second main electrode of the fourth transistor and a second supply terminal.
Claim 4
Dependent Claim
258 words
Differential amplifier as claimed in Claim 2, characterised in that the control electrode of the measuring transistor is connected to the control electrode of the first and the second transistor respectively, and in that the first and the second current generator respectively, further include: - a third transistor of a conductivity type opposite to that of the first transistor, comprising a control electrode, a first and a second main electrode, whilst the control electrode of the third transistor is connected to the first main electrode of the first and the second transistor respectively, and a second main electrode of the third transistor is coupled to a first supply terminal, - a fourth and a fifth transistor of a conductivity type equal to that of the first transistor, the fourth and the fifth transistor comprising each a control electrode and a first and a second main electrode, whilst the first main electrode of the fourth transistor is connected to the first main electrode of the measuring transistor, the first main electrode of the fifth transistor is connected to the first main electrode of the third transistor, the control electrode of the fourth transistor is connected to the second main electrode of the fifth transistor and the control electrode of the fifth transistor is connected to the first main electrode of the fourth transistor, and the second main electrode of the fourth transistor is coupled to a second supply terminal, - a bias current source coupled between the second main electrode of the fifth transistor and the second supply terminal.
Claim 5
Dependent Claim
117 words
Differential amplifier as claimed in Claim 1, characterized in that the first and the second current generator respectively, comprise each: - a measuring resistor included in the first main electrode path of the first and the second transistor respectively, comprising a first resistor terminal coupled to the first main electrode of the first and the second transistor respectively, and including a second resistor terminal coupled to the common terminal, - a measuring transistor of a conductivity type opposite to that of the first and second transistors, comprising a second main electrode coupled to the control output terminal, a control electrode coupled to the first resistor terminal and a first main electrode coupled to the second resistor terminal.
Claim 6
Dependent Claim
141 words
Differential amplifier as claimed in Claim 5, characterised in that the first main electrode of the measuring transistor is connected to the second resistor terminal and in that the first and the second current generator respectively, further include: - a third transistor of a conductivity type opposite to that of the first transistor, comprising a control electrode, a first and a second main electrode, whilst the control electrode of the third transistor is connected to the control electrode of the measuring transistor and the control electrode and the second main electrode of the third transistor are intercoupled at least as regards AC voltage, - a bias current source coupled between the second main electrode of the third transistor and a supply terminal, - a further resistor inserted between the first main electrode of the third transistor and the first resistor terminal.
Claim 7
Dependent Claim
201 words
Differential amplifier as claimed in Claim 5, characterized, in that the control electrode of the measuring transistor is connected to the first resistor terminal and in that the first and the second current generator respectively, additionally include: - a further resistor, - a third transistor of a conductivity type opposite to that of the first transistor, comprising a control electrode, a first and a second main electrode, whilst the control electrode of the third transistor is connected to the second resistor terminal and the first main electrode of the third transistor is connected via the further resistor to the first main electrode of the measuring transistor, - a first bias current source coupled between the second main electrode of the third transistor and a first supply terminal, - a second bias current source coupled between the first main electrode of the measuring transistor and a second supply terminal, - a fourth transistor of the same conductivity type as that of the first transistor, comprising a control electrode and a first and a second main electrode which are coupled to the second main electrode of the third transistor, the first supply terminal and the first main electrode of the measuring transistor respectively.
Claim 8
Dependent Claim
215 words
Differential amplifier as claimed in Claim 5, characterized in that the first and the second current generator respectively, further include each: - a further resistor inserted between the control electrode of the measuring transistor and the first resistor terminal, - a third transistor of a conductivity type opposite to that of the first transistor, comprising a control electrode, a first and a second main electrode, whilst the control electrode of the third transistor is connected to the second resistor terminal and the first main electrode of the third transistor is connected to the first main electrode of the measuring transistor, - a first bias current source connected between the second main electrode of the third transistor and a first supply terminal, - a second bias current source connected between the first main electrode of the measuring transistor and a second supply terminal, - a fourth transistor of the same conductivity type as that of the first transistor, comprising a control electrode and a first and a second main electrode, which are coupled to the second main electrode of the third transistor, the first supply terminal and the first main electrode of the measuring transistor respectively, - a third bias current source connected between the control electrode of the measuring transistor and the first supply terminal.
Claim 9
Dependent Claim
85 words
Differential amplifier as claimed in Claim 1, characterized in that the first and the second current generator respectively, include each: - a measuring transistor of a conductivity type equal to that of the first and second transistors, comprising a second main electrode coupled to the control output terminal, comprising a control electrode coupled to the first main electrode of the first and the second transistor respectively, and comprising a first main electrode coupled to the control electrode of the first and the second transistor respectively.
Claim 10
Dependent Claim
176 words
Differential amplifier as claimed in Claim 9, characterized in that the first main electrode of the measuring transistor is connected to the control electrode of the first and the second transistor respectively, and in that the first and the second current generator respectively, further include each: - a third and a fourth transistor of the same conductivity type as that of the first transistor, comprising each a control electrode, a first and a second main electrode, whilst the control electrode of the third transistor is connected to the second main electrode of the third transistor and to the control electrode of the measuring transistor, the second main electrode of the fourth transistor is connected to the control electrode of the fourth transistor and to the first main electrode of the third transistor and whilst the first main electrode of the fourth transistor is connected to the first main electrode of the first and the second transistor respectively, - a bias current source connected between the second main electrode of the third transistor and a supply terminal.
Claim 11
Dependent Claim
79 words
Differential amplifier as claimed in Claim 10, characterized in that the third transistor, the fourth transistor as well as the bias current source of the first and the second current generator common to the two current generators, whilst the control electrode of the third transistor is connected to the control electrode of the measuring transistor of both the first and the second current generator, and the first main electrode of the fourth transistor is connected to the common terminal.
Claim 12
Dependent Claim
116 words
Differential amplifier as claimed in Claim 1, characterized in that the first and the second current generator respectively, include each: - a measuring resistor included in the first main electrode path of the first and the second transistor respectively, comprising a first resistor terminal coupled to the first main electrode of the first and the second transistor respectively, and a second resistor terminal coupled to the common terminal, - a measuring transistor of a conductivity type equal to that of the first and second transistors, comprising a second main electrode coupled to the control output terminal, a control electrode coupled to the second resistor terminal and a first main electrode coupled to the first resistor terminal.
Claim 13
Dependent Claim
139 words
Differential amplifier as claimed in Claim 12, characterized in that the first main electrode of the measuring transistor is connected to the first resistor terminal and in that the first and the second current generator respectively, further include each: - a further resistor, - a third transistor of the same conductivity type as that of the first transistor, comprising a control electrode, a first and a second main electrode, whilst the control electrode of the third transistor is connected to the second main electrode of the third transistor and to the control electrode of the measuring transistor, and whilst the first main electrode of the third transistor is connected to the second resistor terminal by way of the further resistor, - a bias current source connected between the second main electrode of the third transistor and a supply terminal.
Claim 14
Dependent Claim
74 words
Differential amplifier as claimed in Claim 13, characterized in that the third transistor, the further resistor and the bias current source of the first and the second current generator are common to the two current generators, whilst the control electrode of the third transistor is connected to the control electrode of the measuring transistor of both the first and the second current generator, and whilst the further resistor is connected to the common terminal.
Claim 15
Dependent Claim
60 words
Differential amplifier as claimed in any preceding Claim, characterized in that the controllable quiescent current source is arranged as a transistor of a conductivity type equal to that of the first and second transistors, comprising a control electrode, a first and a second main electrode which are coupled to the control input, a supply terminal and the common terminal respectively.
Claim 16
Dependent Claim
17 words
Differential amplifier as claimed in Claim 15, characterized in that the reference current source is a resistor.
Claim 17
Dependent Claim
33 words
Differential amplifier as claimed in Claim 15 or 16, in so far dependent on Claims 3, 4, 6, 10, 11, 13 and 14, characterized in that the bias current source is a resistor.
Claim 18
Dependent Claim
29 words
Differential amplifier as claimed in Claim 15 or 16, in so far dependent on Claim 7, characterized in that the first and the second bias current source are resistors.
Claim 19
Dependent Claim
31 words
Differential amplifier as claimed in Claim 15 or 16, in so far dependent on Claim 8, characterized in that the first, the second and the third bias current source are resistors.
References Cited (Backward Citations)
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