US3892983A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Switching circuit
Assignee: Sony Corp
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Filing: 1973-09-21
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Granted: 1975-07-01
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Expires: 1993-09-21
Abstract
Abstract A switching circuit in which the signal path between a signal input and a signal output terminal includes at least two amplifier stages, the first one of which has its collector connected in a series circuit with a load impedance and the emitter-collector circuit of a switching transistor. The switching transistor is switched between a conductive and a nonconductive state by a switching voltage applied to its base. The base of a second amplifier stage is connected between the collector of the first stage and the load so that when the switching transistor is made non-conductive by preventing current from flowing in its emitter-collector circuit but also makes the second stage non-conductive by reducing its base current to zero. Making the first stage non-conductive keeps it from amplifying the signal and requires any leakage current to pass around the first stage by means of stray capacitance. Making the first and second stages non-conductive simultaneously prevents even the leakage current from being amplified and allows the leakage current to reach the output terminal only by way of a second stray capacitance, which further reduces the amplitude of such current. A cascode stage may be included between the first and second stages to be rendered non-conductive along with them as a further means of amplifying the signal when the transistors are operative and decoupling the signal when the transistors are nonconductive. Instead of a simple cascode stage, a differential amplifier stage may be included between the first and second stages to provide means for adjusting the gain of the circuit.
Inventors
- 👤 Takashi Okada
- 👤 Isa Nakamura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 17:24
CPC Classifications
H; H04; H04N; H04N9/00; H04N9/64; H04N9/70; H04N9/71; H03; H03F; H03F3/00; H03F3/72; H03K; H03K17/00; H03K17/51; H03K17/56; H03K17/60
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
326 words
A switching circuit for an informational signal comprising: information signal input terminal means; information signal output terminal means; a first semiconductor amplifier device having an input electrode connected to said information signal input terminal means and an output circuit controlled by the information signal applied to said input electrode; switching signal input terminal means to receive a switching signal capable of shifting between an OPEN level and a CLOSED level; a switching semiconductor device having an input electrode and an output circuit controlled thereby; an output load impedance connected in a series circuit between said output circuit of said first semiconductor amplifier device and said output circuit of said switching semiconductor device; first and second voltage supply terminals connected to the opposite ends of said series circuit; circuit means connecting said switching signal input terminal means with said input electrode of said switching semiconductor device including a second switching semiconductor device having an input electrode connected to said switching signal input terminal means and an output circuit controlled by said switching signal to form a low impedance path between said input electrode of the first-named switching semiconductor device and said second voltage supply terminal when said switching signal reaches said OPEN level so that said output circuit of said first-named switching semiconductor device is conductive when said switching signal is at said CLOSED level and non-conductive when said switching signal is at said OPEN level; a second semiconductor ammplifier device having an input electrode and an output circuit connected to said information signal output terminal means and being controlled by the voltage applied to the respective input electrode; and circuit means connecting said input electrode of said second semiconductor amplifier device to said series circuit between said output load impedance and said output circuit of said first semiconductor amplifier device so that said output circuit of the second semiconductor amplifier device is conductive only when said output circuit of said first-named switching semiconductor device is conductive.
Claim 2
Dependent Claim
326 words
A switching circuit for an informational signal comprising: information signal input terminal means; information signal output terminal means; a first semiconductor amplifier device having an input electrode connected to said information signal input terminal means and an output circuit controlled by the information signal applied to said input electrode; switching signal input terminal means to receive a switching signal capable of shifting between an OPEN level and a CLOSED level; a switching semiconductor device having an input electrode and an output circuit controlled thereby; an output load impedance connected in a series circuit between said output circuit of said first semiconductor amplifier device and said output circuit of said switching semiconductor device; first and second voltage supply terminals connected to the opposite ends of said series circuit; circuit means connecting said switching signal input terminal means with said input electrode of said switching semiconductor device including a second switching semiconductor device having an input electrode connected to said switching signal input terminal means and an output circuit controlled by said switching signal to form a low impedance path between said input electrode of the first-named switching semiconductor device and said second voltage supply terminal when said switching signal reaches said OPEN level so that said output circuit of said first-named switching semiconductor device is conductive when said switching signal is at said CLOSED level and non-conductive when said switching signal is at said OPEN level; a second semiconductor ammplifier device having an input electrode and an output circuit connected to said information signal output terminal means and being controlled by the voltage applied to the respective input electrode; and circuit means connecting said input electrode of said second semiconductor amplifier device to said series circuit between said output load impedance and said output circuit of said first semiconductor amplifier device so that said output circuit of the second semiconductor amplifier device is conductive only when said output circuit of said first-named switching semiconductor device is conductive.
Claim 3
Dependent Claim
73 words
The switching circuit of claim 1, in which a third semiconductor amplifier device is connected in cascode between said output circuit of said first semiconductor amplifier device and said input electrode of said second semiconductor amplifier device and additional circuit means connect said third semiconductor amplifier device to said switching signal input terminal means to cause said third semiconductor amplifier device to be non-conductive when said switching signal is at said OPEN level.
Claim 4
Dependent Claim
94 words
The switching circuit of claim 2, in which said third semiconductor amplifier device includes an input electrode and an output circuit interposed in said series circuit between said output load impedance and said output circuit of said first semiconductor amplifier device, and in which said additional circuit means includes an impedance coupling said input electrode of the third semiconductor amplifier device to said input electrode of said first-named switching semiconductor device and unidirectionally conductive means connected in series between said input electrode of said third semiconductor amplifier device and said second voltage supply terminal.
Claim 5
Dependent Claim
110 words
The switching circuit of claim 1, further comprising a third semiconductor amplifier device including an input electrode, and an output circuit connected in series between said output circuit of said first semiconductor amplifier device and said output load impedance; controllable bias means connected to the input electrode of said third semiconductor amplifier device to control the gain of information signals therethrough; and a fourth semiconductor amplifier device biased to be normally conductive and including an output circuit connected in series between said output circuit of said first semiconductor amplifier device and said first voltage supply terminal; and in which said third and fourth semiconductor amplifier devices comprise a differential amplifier.
Claim 6
Dependent Claim
247 words
A switching circuit for an informational signal comprising: information signal input terminal means; information signal output terminal means; a first amplifying transistor having a base electrode connected to said information signal input terminal means and a collector-emitter path having its conductivity controlled by the information signal applied to said base electrode; switching signal input terminal means to receive a switching signal capable of shifting between an OPEN level and a CLOSED level; a switching transistor having a base electrode and a collector-emitter path controlled thereby; an output load resistor connected in a series circuit between said collector-emitter path of said first amplifying transistor and said collector-emitter path of said switching transistor; first and second voltage supply terminals connected to the opposite ends of said series circuit; circuit means connecting said switching signal input terminal means with said base electrode of said switching transistor so that said collector-emitter path of the latter is conductive when said switching signal is at said CLOSED level and non-conductive when said switching signal is at said OPEN level; a second amplifying transistor having a base electrode and collector-emitter path connected to said information signal output terminal means and being controlled by the voltage applied to the respective base electrode; and circuit means connecting said base electrode of said second amplifying transistor to the collector of said first amplifying transistor so that said collector-emitter path of said second amplifying transistor is conductive only when said collectoremitter path of said switching transistor is conductive.
Claim 7
Dependent Claim
247 words
A switching circuit for an informational signal comprising: information signal input terminal means; information signal output terminal means; a first amplifying transistor having a base electrode connected to said information signal input terminal means and a collector-emitter path having its conductivity controlled by the information signal applied to said base electrode; switching signal input terminal means to receive a switching signal capable of shifting between an OPEN level and a CLOSED level; a switching transistor having a base electrode and a collector-emitter path controlled thereby; an output load resistor connected in a series circuit between said collector-emitter path of said first amplifying transistor and said collector-emitter path of said switching transistor; first and second voltage supply terminals connected to the opposite ends of said series circuit; circuit means connecting said switching signal input terminal means with said base electrode of said switching transistor so that said collector-emitter path of the latter is conductive when said switching signal is at said CLOSED level and non-conductive when said switching signal is at said OPEN level; a second amplifying transistor having a base electrode and collector-emitter path connected to said information signal output terminal means and being controlled by the voltage applied to the respective base electrode; and circuit means connecting said base electrode of said second amplifying transistor to the collector of said first amplifying transistor so that said collector-emitter path of said second amplifying transistor is conductive only when said collectoremitter path of said switching transistor is conductive.
Claim 8
Dependent Claim
26 words
A switching circuit according to claim 5; in which said first and second amplifying transistors and said switching transistor are all of the same conductivity type.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-06-30 | 1978-12-30 | 1979-07-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-30 | 1982-12-30 | 1983-07-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-30 | 1986-12-30 | 1987-07-01 | $7700.00 | Window Closed / Lapsed |