US3902111A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Controller output circuit
Assignee: Leeds and Northrup Co
•
Filing: 1974-05-31
•
Granted: 1975-08-26
•
Expires: 1994-05-31
Abstract
Abstract A process controller having an output circuit with a grounded true voltage and current output supplied by a grounded source is provided by using a differential amplifier as an output amplifier driving a transistor so that its emitter-collector path carries an output current from a grounded source through a dropping resistor and the current output. Another differential amplifier with negative feedback is connected across the dropping resistor by a resistance network so that it compares a fraction of the voltage on the high side of the dropping resistor with the same fraction of the difference between its output and the voltage on the lower side of the dropping resistor. By way of the feedback to the output amplifier the compared voltages are kept equal.
Inventors
- 👤 Jr George J Pfisterer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 12:57
CPC Classifications
G; G05; G05F; G05F1/00; G05F1/10; G05F1/46; G05F1/56; G05B; G05B6/00; G05B6/02
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
174 words
A control circuit for producing in response to a control signal a proportional grounded voltage and grounded current output from a grounded power source comprising: a differential output amplifier system for producing an output responsive to the difference between a control signal in the form of a varying voltage indicative of the desired voltage output signal and a feedback signal corresponding to the actual voltage output, a grounded power source connected to supply said amplifier system, a voltage dropping resistor having one end connected to receive the output from said amplifying system, a pair of current output terminals, one of said terminals being connected to the other end of said resistor and the other terminal being connected to ground so that any current load connected across said terminals is in series with said resistor, and a differential feedback amplifier circuit having negative feedback, said feedback amplifier being connected across said dropping resistor by a resistor network so that the feedback amplifier produces the actual voltage output in a predetermined relationship to the current output.
Claim 2
Dependent Claim
174 words
A control circuit for producing in response to a control signal a proportional grounded voltage and grounded current output from a grounded power source comprising: a differential output amplifier system for producing an output responsive to the difference between a control signal in the form of a varying voltage indicative of the desired voltage output signal and a feedback signal corresponding to the actual voltage output, a grounded power source connected to supply said amplifier system, a voltage dropping resistor having one end connected to receive the output from said amplifying system, a pair of current output terminals, one of said terminals being connected to the other end of said resistor and the other terminal being connected to ground so that any current load connected across said terminals is in series with said resistor, and a differential feedback amplifier circuit having negative feedback, said feedback amplifier being connected across said dropping resistor by a resistor network so that the feedback amplifier produces the actual voltage output in a predetermined relationship to the current output.
Claim 3
Dependent Claim
238 words
A control circuit for producing in response to a control signal a proportional grounded voltage and grounded current output from a grounded power source comprising: a differential output amplifier responsive to the difference between a control signal in the form of a varying voltage indicative of the desired change in the manipulated variable of a process and a feedback signal corresponding to said voltage output, a grounded power source, a transistor having its base connected to the output of said differential output amplifier and its emitter and collector connected in circuit with said grounded power source to produce through its emitter-collector path an output current of magnitude related to the output from said amplifier, a voltage dropping resistor connected to form a series circuit with said source and said emitter-collector path, a pair of current output terminals, one of said terminals being connected to said series circuit and the other terminal being connected to ground so that any current load connected across said terminals is in series with said series circuit, and a differential feedback amplifier connected with an input resistor between each of its inputs and opposite sides of said dropping resistor with the non-inverting input connected to ground through a resistor and the inverting input connected to the amplifier output through a feedback resistor so that the feedback amplifier output provides the voltage output signal of said control circuit in magnitude equal to said control signal.
Claim 4
Dependent Claim
238 words
A control circuit for producing in response to a control signal a proportional grounded voltage and grounded current output from a grounded power source comprising: a differential output amplifier responsive to the difference between a control signal in the form of a varying voltage indicative of the desired change in the manipulated variable of a process and a feedback signal corresponding to said voltage output, a grounded power source, a transistor having its base connected to the output of said differential output amplifier and its emitter and collector connected in circuit with said grounded power source to produce through its emitter-collector path an output current of magnitude related to the output from said amplifier, a voltage dropping resistor connected to form a series circuit with said source and said emitter-collector path, a pair of current output terminals, one of said terminals being connected to said series circuit and the other terminal being connected to ground so that any current load connected across said terminals is in series with said series circuit, and a differential feedback amplifier connected with an input resistor between each of its inputs and opposite sides of said dropping resistor with the non-inverting input connected to ground through a resistor and the inverting input connected to the amplifier output through a feedback resistor so that the feedback amplifier output provides the voltage output signal of said control circuit in magnitude equal to said control signal.
Claim 5
Dependent Claim
248 words
A control circuit for producing in response to a control signal a voltage and current output comprising: a differential output amplifier system responsive to the difference between a control signal in the form of a varying voltage indicative of the desired change in the manupulated variable of a process and a feedback signal corresponding to said voltage output, a grounded power source, a transistor having its base connected to the output of said differential output amplifier and its emitter-collector path connected to said grounded power source to produce an output current of magnitude related to the output from said amplifier, a voltage dropping resistor connected to form a series circuit with said source and said emitter-collector path, a pair of current output terminals, one of said terminals being connected to the end of said resistor opposite that connected to said transistor with the other terminal being connected to ground so that any current load connected across said terminals is in series with said series circuit, and a differential feedback amplifier connected with an input resistor between each of its inputs and opposite sides of said dropping resistor with the non-inverting inpuT connected to ground through a resistor and the inverting input connected to the feedback amplifier output through a feedback resistor, all of said resistors being of equal value so that the output of the feedback amplifier provides the voltage output signal between an output terminal and ground which corresponds to the voltage drop across said dropping resistor.
Claim 6
Dependent Claim
248 words
A control circuit for producing in response to a control signal a voltage and current output comprising: a differential output amplifier system responsive to the difference between a control signal in the form of a varying voltage indicative of the desired change in the manupulated variable of a process and a feedback signal corresponding to said voltage output, a grounded power source, a transistor having its base connected to the output of said differential output amplifier and its emitter-collector path connected to said grounded power source to produce an output current of magnitude related to the output from said amplifier, a voltage dropping resistor connected to form a series circuit with said source and said emitter-collector path, a pair of current output terminals, one of said terminals being connected to the end of said resistor opposite that connected to said transistor with the other terminal being connected to ground so that any current load connected across said terminals is in series with said series circuit, and a differential feedback amplifier connected with an input resistor between each of its inputs and opposite sides of said dropping resistor with the non-inverting inpuT connected to ground through a resistor and the inverting input connected to the feedback amplifier output through a feedback resistor, all of said resistors being of equal value so that the output of the feedback amplifier provides the voltage output signal between an output terminal and ground which corresponds to the voltage drop across said dropping resistor.
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) | 1978-08-25 | 1979-02-24 | 1979-08-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-08-25 | 1983-02-24 | 1983-08-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-08-25 | 1987-02-24 | 1987-08-26 | $7700.00 | Window Closed / Lapsed |