EP0283593A1
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EP
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Videoamplifier
Assignee: Canon Production Printing Netherlands BV
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Filing: 1987-03-25
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Granted: —
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Expires: 2007-03-25
Abstract
Abstract A videoamplifier including at least one transistor amplifying circuit (T₁, T₂, 10, 18, 20) which is designed in such a way that the transistors (T₁, T₂) will exhibit a linear characteristic in a range of small variations of the input signal (V i ) and a hard switching characteristic in response to large input signal variations. Due to this circuit design, the output signal (V o ) will, in general, be proportional to the input signal (V i ) but will be able to respond more quickly to a sudden increase of the input signal.
Inventors
- 👤 Johannes Mathieu Marie Simons
- 👤 Casper Paul Mathilde Michels
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 21:13
CPC Classifications
H; H03; H03F; H03F3/00; H03F3/189; H03F3/19; H03F3/42; H03F3/45; H03F3/45071; H03F3/45076; H03F3/4508; H03F3/45085; H03F3/45089; H04; H04N; H04N5/00; H04N5/14; H04N5/148
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
60 words
A videoamplifier including at least one transistor amplifying circuit (T₁, T₂, 10, 18, 20), characterized in that said amplifying circuit is designed is such a way that the transistors (T₁, T₂) exhibit a linear characteristic in a range of small variations of the input signal (V i ) and a hard switching characteristic in response to large input signal variations.
Claim 2
Dependent Claim
60 words
A videoamplifier including at least one transistor amplifying circuit (T₁, T₂, 10, 18, 20), characterized in that said amplifying circuit is designed is such a way that the transistors (T₁, T₂) exhibit a linear characteristic in a range of small variations of the input signal (V i ) and a hard switching characteristic in response to large input signal variations.
Claim 3
Dependent Claim
132 words
An amplyfying circuit characterized by - a first current source (10) connected to a branched circuit (12), - first transistor means (T₁) provided in a first branch (14) of said branched circuit, said first transistor means being responsive to the input voltage (V i ) to control a current (I₁) flowing in said first branch (14), - a second current source (18) provided in a second branch (16) of said branched circuit, - second transistors means (T₂; T₂₁, T₂₂) provided in said second branch (16) between said first and second current sources (10, 18) and - a feedback circuit (20) for deriving from the output voltage (V o ) picked-up between the second current source (18) and the second transistor means a control signal (V b2 ) for the second transistor means.
Claim 4
Dependent Claim
132 words
An amplyfying circuit characterized by - a first current source (10) connected to a branched circuit (12), - first transistor means (T₁) provided in a first branch (14) of said branched circuit, said first transistor means being responsive to the input voltage (V i ) to control a current (I₁) flowing in said first branch (14), - a second current source (18) provided in a second branch (16) of said branched circuit, - second transistors means (T₂; T₂₁, T₂₂) provided in said second branch (16) between said first and second current sources (10, 18) and - a feedback circuit (20) for deriving from the output voltage (V o ) picked-up between the second current source (18) and the second transistor means a control signal (V b2 ) for the second transistor means.
Claim 5
Dependent Claim
59 words
An amplifying circuit as claimed in claim 2, wherein said feedback circuit (20) comprises a first resistor (R₁; R₁₁, R₁₂) connected between the collector and the base of said second transistor means, a second resistor (R₂) connected between the base of said second transistor means and ground and a capacitor (C₂) connected in parallel to said second resistor (R₂).
Claim 6
Dependent Claim
73 words
An amplifying circuit as claimed in claim 2 or 3, wherein the current (I₁) flowing in said first branch (14) is delivered by a third current source (22) and wherein said second current source (18) is interlocked with said third current source (22) such that a change of the current (I₁) in said first branch (14) is reflected by a like change of the current (I₂) delivered by said second current source (18).
Claim 7
Dependent Claim
45 words
An amplifying circuit as claimed in any of the claims 2 to 4, wherein said second transistor means (T₂₁, T₂₂) and/or said second and third current sources (18, 22) each include at least two transistors (T₂₁, T₂₂; T₄₁, T₄₂, T₆; T₅, T₇) connected in series.
Claim 8
Dependent Claim
129 words
An amplifying circuit as claimed in any of the claims 2 to 4, wherein said second branch (16) comprises first and second additional transistors (T₈, T₉) that are connected in series between said second transistor means (T₂) and said second current source (18), the output voltage (V o ) being picked-up at a point between said additional transistors, and wherein the bases of the additional transistors are respectively connected to constant voltage terminals (+V₄, +V₅) the voltages of which are selected in such a manner that the additional transistors are not saturated and the voltage drop across each of said additional transistors is larger than the voltage drop across said second transistor means (T₂) and than the voltage drop across an output transistor (T₆) of said second current source.
Claim 9
Dependent Claim
27 words
An amplifying circuit as claimed in claims 4 and 6, wherein said feedback circuit (20) comprises another capacitor (C₁) connected in parallel to said first resistor (R₁).
Claim 10
Dependent Claim
57 words
An amplifying circuit as claimed in claim 6 or 7, wherein a third additional transistor T₁₀ is interposed between said first current source (10) and said first transistor means (T₁) and has its base connected to the same voltage terminal (+V₄) as the first additional transistor (T₈) that is connected directly to the second transistor means (T₂).
References Cited (Backward Citations)
US3689848A
Cited
US4414574A
Cited
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