US3902806A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Constant current-pulse led drive circuit
Assignee: American Optical Corp
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Filing: 1974-04-22
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Granted: 1975-09-02
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Expires: 1994-04-22
Abstract
Abstract A circuit for use with an oximeter system which provides constant current pulses to light-emitting diodes in a sequential and cyclical manner. The circuit maintains magnitudes of pulses in the pulse train equal to certain other pulses in the pulse train over extremes of temperature variation, voltage variation, and time duration. Each diode is energized by a series of pulses having the same magnitude, although pulse magnitudes will vary from diode to diode. Therefore, light output from one lightemitting diode remains proportional to light output from the others.
Inventors
- 👤 Robert E Bober
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 00:18
CPC Classifications
G; G05; G05F; G05F1/00; G05F1/10; G05F1/46; G05F1/56; G01; G01N; G01N21/00; G01N21/17; G01N21/25; G01N21/255
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
139 words
An oximeter system including a plurality of light-emitting diodes, means for energizing said plurality of diodes, a specimen, means for directing light emitted from said diodes on said specimen, means for detecting light reflected from said specimen, means for converting said detected light to electrical signals and for processing said signals, means for extracting information about said specimen from said signals, said energizing means comprising at least one electrical power supply, means for generating a series of current pulses from said supply, means for controlling the magnitude of each of said pulses of said series to be constant and equal to only certain other pulses of said series, and means for sequentially and cyclically applying said constant magnitude pulses to said plurality of diodes so that each of said diodes is energized only by pulses having the same magnitude.
Claim 2
Dependent Claim
139 words
An oximeter system including a plurality of light-emitting diodes, means for energizing said plurality of diodes, a specimen, means for directing light emitted from said diodes on said specimen, means for detecting light reflected from said specimen, means for converting said detected light to electrical signals and for processing said signals, means for extracting information about said specimen from said signals, said energizing means comprising at least one electrical power supply, means for generating a series of current pulses from said supply, means for controlling the magnitude of each of said pulses of said series to be constant and equal to only certain other pulses of said series, and means for sequentially and cyclically applying said constant magnitude pulses to said plurality of diodes so that each of said diodes is energized only by pulses having the same magnitude.
Claim 3
Dependent Claim
88 words
A system as recited in claim 1 and wherein said energizing means further comprises a regulated power supply and an unregulated power supply, current regulator transistOr means energized by said unregulated supply, operational amplifier means for biasing said transistor means from said unregulated supply, feedback bridge means connected between the input of said operational amplifier means and said current regulator transistor means for establishing said magnitude of said each of said pulses, and control pulse distribution means for simultaneously controlling said feedback bridge means and said applying means.
References Cited (Backward Citations)
US3647299A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-09-01 | 1979-03-03 | 1979-09-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-01 | 1983-03-03 | 1983-09-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-01 | 1987-03-03 | 1987-09-02 | $7700.00 | Window Closed / Lapsed |