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Patent US3786279A successfully refreshed from Google Patents.
US3786279A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Adaptive transistor switch
Assignee: Motorola Solutions Inc
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Filing: 1972-05-30
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Granted: 1974-01-15
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Expires: 1992-05-30
Abstract
Abstract A transistor switch connecting a load to a suitable source of power with amplifying means supplying base current to the transistor switch with a voltage sensitive device, such as a diode or a transistor, connected to sense the voltage across the transistor switch and provide an alternate path for driving current to the amplifier to maintain base current into the transistor switch at a predetermined ratio relative to current flowing through the transistor switch and the load.
Inventors
- 👤 W Wilson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 17:00
CPC Classifications
H; H03; H03K; H03K17/00; H03K17/51; H03K17/56; H03K17/60
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
182 words
An improved semiconductor switching circuit for variable loads and the like comprising: a. semiconductor means adapted to be connected to a load and a suitable source of power so as to conduct electric current from the source to the load; b. means connected across said semiconductor means and sensitive to the voltage drop across said semiconductor means; and c. circuit means having first and second modes of operation and including amplifying means connected to receive a driving current during the first mode of operation and coupled to said semiconductor means and to said voltage sensitive means for providing control current to said semiconductor means, said circuit means maintaining said semiconductor means nonconducting in the first mode of operation and providing control current to maintain said semiconductor means saturated in the second mode of operation, and said voltage sensitive means controlling an alternate path for the driving current supplied to said amplifying means during saturated operation of said semiconductor means to maintain the control current being applied to the semiconductor means and the current flowing through the semiconductor means at a predetermined ratio.
Claim 2
Dependent Claim
182 words
An improved semiconductor switching circuit for variable loads and the like comprising: a. semiconductor means adapted to be connected to a load and a suitable source of power so as to conduct electric current from the source to the load; b. means connected across said semiconductor means and sensitive to the voltage drop across said semiconductor means; and c. circuit means having first and second modes of operation and including amplifying means connected to receive a driving current during the first mode of operation and coupled to said semiconductor means and to said voltage sensitive means for providing control current to said semiconductor means, said circuit means maintaining said semiconductor means nonconducting in the first mode of operation and providing control current to maintain said semiconductor means saturated in the second mode of operation, and said voltage sensitive means controlling an alternate path for the driving current supplied to said amplifying means during saturated operation of said semiconductor means to maintain the control current being applied to the semiconductor means and the current flowing through the semiconductor means at a predetermined ratio.
Claim 3
Dependent Claim
20 words
An improved semiconductor switching circuit as set forth in claim 1 wherein the semiconductor means includes at least one transistor.
Claim 4
Dependent Claim
43 words
An improved semiconductor switching circuit as set forth in claim 2 wherein the circuit means is connected to tHe base of the transistor to apply control current to the base and collector current of the transistor is adapted to flow through the load.
Claim 5
Dependent Claim
35 words
An improved semiconductor switching circuit as set forth in claim 3 wherein the voltage sensitive means is connected to the amplifying means to provide an alternate path for the driving current to the amplifying means.
Claim 6
Dependent Claim
33 words
An improved semiconductor switching circuit as set forth in claim 4 wherein the voltage sensitive means includes a diode connected to increase the driving current when the voltage drop across the transistor increases.
Claim 7
Dependent Claim
33 words
An improved semiconductor switching circuit as set forth in claim 4 wherein the voltage sensitive means includes a transistor connected to increase the driving current when the voltage drop across the transistor increases.
Claim 8
Dependent Claim
152 words
An improved method of controlling current through a variable load comprising the steps of: a. connecting transistor means to said load and a suitable current source so that load current flows through said transistor means in a saturated mode of operation and substantially no load current flows through said transistor means in a nonconducting mode; b. sensing the voltage drop across said transistor means during the saturated mode of operation; c. supplying base current to said transistor means through amplifying means having an input with driving current applied thereto; and d. providing an alternate path for a variable portion of the driving current in response to the voltage drop sensed across said transistor means, said alternate path receiving a smaller amount of driving current as the voltage drop increases for maintaining the load current flowing through said transistor means and the base current applied to said transistor means at a predetermined ratio.
Claim 9
Dependent Claim
152 words
An improved method of controlling current through a variable load comprising the steps of: a. connecting transistor means to said load and a suitable current source so that load current flows through said transistor means in a saturated mode of operation and substantially no load current flows through said transistor means in a nonconducting mode; b. sensing the voltage drop across said transistor means during the saturated mode of operation; c. supplying base current to said transistor means through amplifying means having an input with driving current applied thereto; and d. providing an alternate path for a variable portion of the driving current in response to the voltage drop sensed across said transistor means, said alternate path receiving a smaller amount of driving current as the voltage drop increases for maintaining the load current flowing through said transistor means and the base current applied to said transistor means at a predetermined ratio.
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) | 1977-01-14 | 1977-07-16 | 1978-01-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-01-14 | 1981-07-16 | 1982-01-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-01-14 | 1985-07-16 | 1986-01-15 | $7700.00 | Window Closed / Lapsed |