US4027228A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Photocoupled isolated switching amplifier circuit
Assignee: General Electric Co
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Filing: 1976-03-23
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Granted: 1977-05-31
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Expires: 1996-03-23
Abstract
Abstract A switching transistor inverter circuit for driving high power AC loads such as arc discharge lamps from a DC electrical energy source. Each switching transistor is included in a switching amplifier whose response time is short as compared with the response characteristic of the load and the AC cycle period. A single driver circuit is coupled to the respective switching amplifiers by photocouple isolation means through an electrooptically coupled light emitter-sensor pair. A clock pulse generator provides the necessary signal to the driver circuit which includes a phase splitter driver. A two-stage amplifier receives the signal from the sensor transistor of the photocouple and amplifies it to drive the switching transistor which is, in the preferred embodiment, a power darlington device of the monolithic type.
Inventors
- 👤 James R. Collins
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 17:55
CPC Classifications
H; H02; H02M; H02M7/00; H02M7/42; H02M7/44; H02M7/48; H02M7/53; H02M7/537; H02M7/5387; H02M7/53871; Y; Y10; Y10S; Y10S323/00; Y10S323/902
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
114 words
A switching amplifier circuit for the electrically isolated coupling of an imput logic circuit with a load, comprising: a light-emitting diode- phototransistor isolation pair wherein the phototransistor collector circuit is connected in a low impedance circuit to provide current limiting by the intrinsic current transfer ratio of the isolation pair to enhance switching speed; an output power transistor for controlling output power to the load; a current amplifying and level-shifting means connected between the output of the isolation pair and the output power transistor for providing forward and reverse base drive thereto; and a line - operated D. C. power supply connected to the current amplifying and level-shifting means for providing operation power thereto.
Claim 2
Dependent Claim
114 words
A switching amplifier circuit for the electrically isolated coupling of an imput logic circuit with a load, comprising: a light-emitting diode- phototransistor isolation pair wherein the phototransistor collector circuit is connected in a low impedance circuit to provide current limiting by the intrinsic current transfer ratio of the isolation pair to enhance switching speed; an output power transistor for controlling output power to the load; a current amplifying and level-shifting means connected between the output of the isolation pair and the output power transistor for providing forward and reverse base drive thereto; and a line - operated D. C. power supply connected to the current amplifying and level-shifting means for providing operation power thereto.
Claim 3
Dependent Claim
35 words
The switching amplifier circuit of claim 1, wherein the DC power supply is of the type having a line isolating step-down transformer with secondary winding feeding a full-wave rectifier and a capacitor filter output circuit.
Claim 4
Dependent Claim
33 words
The switching amplifier circuit of claim 1 wherein the phototransistor collector-emitter output is solely connected in a low impedance loop to the emitter-base junction of a following amplifier stage and the DC supply.
Claim 5
Dependent Claim
30 words
The switching amplifier circuit of claim 1 wherein the circuit of the isolation pair further includes a resistor connected between the base of the output phototransistor and the DC supply.
Claim 6
Dependent Claim
42 words
The switching amplifier circuit of claim 1, wherein the current amplifying and level-shifting means comprises: a saturating common-emitter amplifier connected to the output of the isolation pair; and a complementary drive amplifier connecting the saturating common-emitter amplifier with the output power transistor.
Claim 7
Dependent Claim
61 words
The switching amplifier circuit of claim 5 wherein the saturating amplifier includes: a common emitter connected transistor whose emitter-base junction is connected to the phototransistor; and a first resistor connected as the collector load and a second resistor connected between the junction of the first resistor and the collector of the transistor and the input of a following complementary drive amplifier.
Claim 8
Dependent Claim
18 words
The switching amplifier circuit of claim 6 further including a diode connected in parallel with the second resistor.
Claim 9
Dependent Claim
58 words
The switching amplifier circuit of claim 5 wherein the complementary drive amplifier includes: a first transistor connected to a second transistor, the base terminals of each being common; and the emitter terminal of each being common and collector load resistors for the respective transistors, the common emitter terminals being connected to the input of the output power transistor.
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) | 1980-05-30 | 1980-11-29 | 1981-05-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-05-30 | 1984-11-29 | 1985-05-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-05-30 | 1988-11-29 | 1989-05-31 | $7700.00 | Window Closed / Lapsed |