US3821515A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for the control of electrical heating
Assignee: Siemens AG
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Filing: 1973-01-04
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Granted: 1974-06-28
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Expires: 1993-01-04
Abstract
Abstract Apparatus for controlling the electrical heating of a semiconductor rod as it is being formed by deposition of semiconductor material from a gaseous atmosphere includes a switching circuit for connecting an a.c. power source in series with the semiconductor rod for heating the same, a rectifier inductively coupled with the heating circuit for deriving a d.c. signal proportional to the arithmetic mean value heating current, and amplifier means having a feedback network for generating a d.c. voltage for controlling operation of the switching circuit in accordance with the effective value of the heating current. In another form of the apparatus, an amplifier having a feedback network has its input connected to an a.c. signal proportional to the heating current and generates a d.c. voltage which is a function of the effective heating current for controlling operation of the switching circuit.
Inventors
- 👤 H Stut
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 03:26
CPC Classifications
C; C23; C23C; C23C16/00; C23C16/44; C23C16/52; G; G05; G05F; G05F1/00; G05F1/10; G05F1/12; G05F1/40; G05F1/44; G05F1/45; G05F1/455
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
199 words
In apparatus for electrically heating a growing semiconductor rod during a deposition process, including a heating source of alternating current connected to the semiconductor rod, an electronic switch connected in circuit with the rod and said heating source of alternating current to form a heating current circuit, a source of auxiliary voltage having an output voltage which varies with time connected to control said electronic switch to control the flow of heating current through said rod, a second current circuit inductively coupled to said heating circuit for providing a rectified signal representative of the heating current, and modifying means connected between said second current circuit and said source of auxiliary voltage for controlling said source of auxiliary voltage, said modifying means including a low pass filter, a control amplifier and manually adjustable means for controlling the addition of a bias potential to the output of said modifying means, said control amplifier having a pair of feedback resistors connected in series between its input and its output, a correction circuit including a plurality of potentiometers connected in series, the taps of each of said potentiometers being connected through individual resistors and diodes to the common connection between saiD feedback resistors.
Claim 2
Dependent Claim
199 words
In apparatus for electrically heating a growing semiconductor rod during a deposition process, including a heating source of alternating current connected to the semiconductor rod, an electronic switch connected in circuit with the rod and said heating source of alternating current to form a heating current circuit, a source of auxiliary voltage having an output voltage which varies with time connected to control said electronic switch to control the flow of heating current through said rod, a second current circuit inductively coupled to said heating circuit for providing a rectified signal representative of the heating current, and modifying means connected between said second current circuit and said source of auxiliary voltage for controlling said source of auxiliary voltage, said modifying means including a low pass filter, a control amplifier and manually adjustable means for controlling the addition of a bias potential to the output of said modifying means, said control amplifier having a pair of feedback resistors connected in series between its input and its output, a correction circuit including a plurality of potentiometers connected in series, the taps of each of said potentiometers being connected through individual resistors and diodes to the common connection between saiD feedback resistors.
Claim 3
Dependent Claim
22 words
Apparatus according to claim 1, wherein said low pass filter, said control amplifier and said manually adjustable means are connected in series.
Claim 4
Dependent Claim
42 words
Apparatus according to claim 1, wherein the output of said control amplifier is connected to the input of said low pass filter, and including a further amplifier interconnected between the input of said modifying means and the input of said control amplifier.
Claim 5
Dependent Claim
54 words
Apparatus according to claim 1, including a further amplifier, said further amplifier having its input connected to the output of said control amplifier and to the output of said manually adjustable means, said further amplifier having its output connected to the output of said modifying means and to the input of said control amplifier.
Claim 6
Dependent Claim
48 words
Apparatus according to claim 3, including a resistor coupling the output of said further amplifier with the input of said control amplifier, and a summing circuit connecting both the output of said further amplifier and the output of said control amplifier to the input of said further amplifier.
Claim 7
Dependent Claim
39 words
Apparatus according to claim 4, including a coupling resistor connected from the output of said summing circut to the input of said further amplifier and a feedback resistor connected between the input and the output of said further amplifier.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-06-27 | 1977-12-27 | 1978-06-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-27 | 1981-12-27 | 1982-06-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-27 | 1985-12-27 | 1986-06-28 | $7700.00 | Window Closed / Lapsed |