EP0478204A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Thermo-electric temperature control arrangement for laser apparatus
Assignee: AT&T Inc
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Filing: 1991-09-17
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Granted: —
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Expires: 2011-09-17
Abstract
Abstract A thermo-electric laser temperature control apparatus is driven by a switching mode control circuit (317, 315). Driving current polarity (via 321 or 322) determines if the thermo-electric apparatus (305) is operating in a heat absorbent or heat generating mode. A sequencing control circuit (361-364) is used in association with the control circuit to define operative ranges of the thermo-electric temperature control apparatus consistent with maintaining proper temperature for a linear operative range for the laser. Feedback circuitry permits precision control of the converter output to limit the operative temperature range of the laser to a small precisely defined temperature window.
Inventors
- 👤 James Mcardle
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 19:00
CPC Classifications
G; G05; G05D; G05D23/00; G05D23/19; G05D23/1919; F; F25; F25B; F25B2321/00; F25B2321/02; F25B2321/021; F25B2321/0212
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
164 words
A thermo-electric device control circuit for controlling a temperature of a laser device, comprising a thermo-electric device (305) physically connected to the laser device, a periodic switching circuit having a power switch (315) with a controllable duty cycle connected for applying a current to the thermo-electric device, and CHARACTERISED BY means for controlling a direction and a magnitude of the current, comprising means (351,352) for generating a voltage responsive to a temperature of the laser device, switching circuitry (321,322) for coupling the current output of the power switch to the thermo-electric device in one of at least a first direction and second direction opposite the first direction, and means (361-346, 371-374, 381, 317) responsive to the voltage for controlling the duty cycle to control a magnitude of the current of the power switch applied to the thermo-electric device, and for controlling the switching circuitry to select one of the first and second direction in order to maintain the laser device at a desired temperature.
Claim 2
Dependent Claim
148 words
A circuit as claimed in claim 1, wherein the means responsive to the voltage comprises first, second, third and fourth amplifiers (361-364) each biased by a first, second, third and fourth bias voltage having ordered descending magnitudes, respectively, the second (362) and third (363) amplifiers being biased to be operative in the alternative depending upon a level of the voltage being greater than or less than a midpoint voltage and connected to the switching circuitry to control direction of current applied to the thermo-electric device, the first amplifier (361) being biased to generate a signal to control a magnitude of the current of the power switch when the second amplifier is controlling the direction of current, and the fourth amplifier (364) being biased to generate a signal to control a magnitude of the current of the power switch when the third amplifier is controlling the direction of current.
Claim 3
Dependent Claim
71 words
A circuit as claimed in claim 1 or 2, comprising a power transformer (325) having a primary winding (324) and a first (326) and second (327) secondary winding, the power switch being connected to periodically energize the primary winding, and the switching circuitry comprising a first switch (321) coupling the first secondary winding to the thermo-electric device, and a second switch (322) coupling the second secondary winding to the thermo-electric device.
Claim 4
Dependent Claim
30 words
A circuit as claimed in claim 1, 2 or 3, comprising shutdown circuitry (393, 397) for disabling the periodic switching circuit when the control circuit senses a loss of voltage.
Claim 5
Dependent Claim
32 words
A circuit as claimed in claim 1, 2, 3 or 4, comprising alarm circuitry (392) for indicating inability of the control circuitry to maintain a proper operative temperature for the laser device.
References Cited (Backward Citations)
No citation records indexed.
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