US3720846A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Integrating amplifier circuits
Assignee: Servomex Controls Ltd
•
Filing: 1971-06-04
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Granted: 1973-03-13
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Expires: 1991-06-04
Abstract
Abstract An integrating amplifier circuit is provided which overcomes the problem of input voltage offset and enables a cheaper amplifier to be employed in a given situation. Input circuits are disclosed which behave as current generators to achieve the desired result.
Inventors
- 👤 A Borer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 00:31
CPC Classifications
H; H03; H03F; H03F3/00; H03F3/20; H03F3/21; H03F3/217
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
157 words
An integrating amplifier having an output terminal adapted to constitute a source of reference signals and an input circuit adapted for connection to a source of control signals, wherein a. said input circuit comprises a pulse-width modulator connected to the amplifier by way of a switch which is closed only during the ''''mark'''' periods of the modulator and is open during the ''''space'''' periods whereby the potential of the amplifier input floats freely during said ''''space'''' periods, and b. the modulator is constructed with circuit parameters such that i. the output signal from the modulator is of such a magnitude that the effect of the amplifier offset is negligibly small in comparison with the effect of the modulator signal, and ii. the mark period of the modulator is very small in proportion to its space period and the ratio therebetween is variable through a range of values resulting in driving of the amplifier through itS working range.
Claim 2
Dependent Claim
157 words
An integrating amplifier having an output terminal adapted to constitute a source of reference signals and an input circuit adapted for connection to a source of control signals, wherein a. said input circuit comprises a pulse-width modulator connected to the amplifier by way of a switch which is closed only during the ''''mark'''' periods of the modulator and is open during the ''''space'''' periods whereby the potential of the amplifier input floats freely during said ''''space'''' periods, and b. the modulator is constructed with circuit parameters such that i. the output signal from the modulator is of such a magnitude that the effect of the amplifier offset is negligibly small in comparison with the effect of the modulator signal, and ii. the mark period of the modulator is very small in proportion to its space period and the ratio therebetween is variable through a range of values resulting in driving of the amplifier through itS working range.
Claim 3
Dependent Claim
157 words
An integrating amplifier having an output terminal adapted to constitute a source of reference signals and an input circuit adapted for connection to a source of control signals, wherein a. said input circuit comprises a pulse-width modulator connected to the amplifier by way of a switch which is closed only during the ''''mark'''' periods of the modulator and is open during the ''''space'''' periods whereby the potential of the amplifier input floats freely during said ''''space'''' periods, and b. the modulator is constructed with circuit parameters such that i. the output signal from the modulator is of such a magnitude that the effect of the amplifier offset is negligibly small in comparison with the effect of the modulator signal, and ii. the mark period of the modulator is very small in proportion to its space period and the ratio therebetween is variable through a range of values resulting in driving of the amplifier through itS working range.
Claim 4
Dependent Claim
157 words
An integrating amplifier having an output terminal adapted to constitute a source of reference signals and an input circuit adapted for connection to a source of control signals, wherein a. said input circuit comprises a pulse-width modulator connected to the amplifier by way of a switch which is closed only during the ''''mark'''' periods of the modulator and is open during the ''''space'''' periods whereby the potential of the amplifier input floats freely during said ''''space'''' periods, and b. the modulator is constructed with circuit parameters such that i. the output signal from the modulator is of such a magnitude that the effect of the amplifier offset is negligibly small in comparison with the effect of the modulator signal, and ii. the mark period of the modulator is very small in proportion to its space period and the ratio therebetween is variable through a range of values resulting in driving of the amplifier through itS working range.
Claim 5
Dependent Claim
76 words
A current measuring circuit comprising an integrating amplifier as claimed in claim 1 in which additionally a. a current input terminal is connected directly to the amplifier input, and b. the output terminal of the amplifier is connected to the input circuit, whereby the reference signals act as control signals and the amplifier seeks an equilibrium condition with the average current output from the integrator equal and opposite to the current from the current input terminal.
Claim 6
Dependent Claim
22 words
An integrating amplifier according to claim 1 wherein the output from said pulse width modulator is provided by a constant current generator.
Claim 7
Dependent Claim
14 words
An integrating amplifier according to claim 3 wherein said switch is a low-leakage diode.
Claim 8
Dependent Claim
39 words
A ramp generator comprising an integrating amplifier according to claim 3 wherein a second constant current generator in said pulse width modulator is connected to feed to said input circuit a signal equal and opposite to said control signal.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-03-12 | 1976-09-11 | 1977-03-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-12 | 1980-09-11 | 1981-03-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-12 | 1984-09-11 | 1985-03-13 | $7700.00 | Window Closed / Lapsed |