US3889137A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Circuit arrangements comprising a switching transistor
Assignee: US Philips Corp
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Filing: 1973-12-10
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Granted: 1975-06-10
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Expires: 1993-12-10
Abstract
Abstract An arrangement for driving a switching transistor in which a current sensing resistor is connected between an input amplifier and the switching transistor. A feedback loop is created by a transistor having its base-emitter junction coupled to the current sensing resistor and its collector supplying the feedback signal to the amplifier input. The arrangement insures saturated switching of the switching transistor over a range of operating conditions.
Inventors
- 👤 Malcolm John Kay
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 16:39
CPC Classifications
H; H03; H03K; H03K17/00; H03K17/14; H03K17/04; H03K17/041; H03K17/0412; H03K17/04126
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
112 words
A switching circuit arrangement comprising: a switching transistor; means for supplying a switching signal for rendering said switching transistor conductive; an amplifier for supplying said switching signal to said switching transistor, said amplifier having a current sensing impedence connected between the amplifier output and the base of the switching transistor; and a feedback transistor for supplying a negative feedback signal to the input of the amplifier, said feedback transistor having its base-emitter junction connected across the current sensing impedance and having its collector supplying said feedback signal to the amplifier input, the base current being supplied to the switching transistor also operating to forward bias the base-emitter junction of the feedback transistor.
Claim 2
Dependent Claim
112 words
A switching circuit arrangement comprising: a switching transistor; means for supplying a switching signal for rendering said switching transistor conductive; an amplifier for supplying said switching signal to said switching transistor, said amplifier having a current sensing impedence connected between the amplifier output and the base of the switching transistor; and a feedback transistor for supplying a negative feedback signal to the input of the amplifier, said feedback transistor having its base-emitter junction connected across the current sensing impedance and having its collector supplying said feedback signal to the amplifier input, the base current being supplied to the switching transistor also operating to forward bias the base-emitter junction of the feedback transistor.
Claim 3
Dependent Claim
53 words
A circuit arrangement as claimed in claim 1 in which the circuit elements of the arrangement are preselected so that over the anticipated range of operating conditions, the magnitude of the base current supplied to the switching transistor in response to the switching signal is at least equal to that required for saturation.
Claim 4
Dependent Claim
35 words
A circuit arrangement as claimed in claim 2 in which the said circuit elements are preselected so that, over a significant portion of said anticipated range, the base current drive in excess of that required.
Claim 5
Dependent Claim
51 words
A circuit arrangement as claimed in claim 1 in which said feedback transistor creates a negative feedback loop, the gain within the feedback loop being such that the feedback current from the collector of said feedback signal supplying transistor is small compared to the current flowing through said current sensing impedance.
Claim 6
Dependent Claim
47 words
A circuit arrangement as claimed in claim 1 in which the said amplifier is in the form of a driving transistor connected in emitter-follower configuration, said feedback signal derived from the collector of said feedback signal supplying transistor being applied to the base of the driving transistor.
Claim 7
Dependent Claim
32 words
A circuit arrangement as claimed in claim 5 in which the switching signal from the said switching signal source is supplied to base of the said driving transistor via a series impedance.
Claim 8
Dependent Claim
22 words
A circuit arrangement as claimed in claim 1 in which the said current sensing impedance is in the form of a resistance.
References Cited (Backward Citations)
US3283244A
Cited
US3678291A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-06-09 | 1978-12-09 | 1979-06-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-09 | 1982-12-09 | 1983-06-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-09 | 1986-12-09 | 1987-06-10 | $7700.00 | Window Closed / Lapsed |