US3808463A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Integrated function generator
Assignee: US Philips Corp
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Filing: 1972-08-21
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Granted: 1974-04-30
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Expires: 1992-08-21
Abstract
Abstract The integrated circuit described is a function generator which, for example, is eminently suited for use in a shutter system of an automatic photographic camera. The current which is delivered by the photodiode and is a measure of the intensity of the light incident on the objective of the camera is supplied to this function generator as the input current. This current is converted, by means of a voltage which is generated in the generator and is a function of the film speed of the film used and the diaphragm stop, into an output current which is supplied to an integrating circuit. The value of the said output current and the integrating circuit then determine the exposure time.
Inventors
- 👤 C Mulder
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 06:13
CPC Classifications
G; G03; G03B; G03B7/00; G03B7/08; G03B7/081; G03B7/083; G11; G11C; G11C27/00; G11C27/02; G11C27/024; G11C27/028; H; H03; H03F; H03F3/00; H03F3/34; H03F3/343; H03F3/347
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
173 words
Integrated circuit for producing an output current having a predetermined non-linear relationship to an input current comprising, an input terminal adapted to receive said input current and an output terminal for supplying said output current, an amplifier provided with negative feedback and having an input circuit and an output circuit from which the output current is derived, a switch, means connecting the negative-feedback impedance via said switch from the amplifier output circuit to the input circuit of the amplifier so that the negative feedback impedance determines the prescribed non-linear relationship between the input and output currents, means including said switch for selectively coupling the amplifier input circuit to said input terminal, means for coupling said output terminal to the amplifier output circuit, and means for connecting said amplifier input circuit to a storage capacitor for maintaining said predetermined non-linear relationship when the switch is opened at a given operating instant and at the last value of the input current prior to the operating instant and irrespective of further variations of the input current.
Claim 2
Dependent Claim
173 words
Integrated circuit for producing an output current having a predetermined non-linear relationship to an input current comprising, an input terminal adapted to receive said input current and an output terminal for supplying said output current, an amplifier provided with negative feedback and having an input circuit and an output circuit from which the output current is derived, a switch, means connecting the negative-feedback impedance via said switch from the amplifier output circuit to the input circuit of the amplifier so that the negative feedback impedance determines the prescribed non-linear relationship between the input and output currents, means including said switch for selectively coupling the amplifier input circuit to said input terminal, means for coupling said output terminal to the amplifier output circuit, and means for connecting said amplifier input circuit to a storage capacitor for maintaining said predetermined non-linear relationship when the switch is opened at a given operating instant and at the last value of the input current prior to the operating instant and irrespective of further variations of the input current.
Claim 3
Dependent Claim
38 words
Integrated circuit as claimed in claim 1, wherein the negative-feedback impedance comprises a current source which includes at least a diode and a transistor, the diode being connected in parallel with the base emitter circuit of the transistor.
Claim 4
Dependent Claim
26 words
Integrated circuit as claimed in claim 1 characterized in that the input current is supplied to a junction point between the switch and the negative-feedback impedance.
Claim 5
Dependent Claim
47 words
Integrated circuit as claimed in claim 1 including a diode and an auxiliary transistor connected so that the input current is supplied via said diode to the input circuit of the amplifier and also via the collector emitter path of said auxiliary transistor to the negative-feedback impedance.
Claim 6
Dependent Claim
116 words
Integrated circuit as claimed in claim 2 wherein the switch comprises an electronic switch and the amplifier includes a plurality of other transistors the base emitter paths of which are connected in series, means connecting the end of said series combination remote from the input of the amplifier via said diode to a voltage supply point, means connecting the collector of the transistor of the negative-feedback impedance to said electronic switch and its emitter via a voltage source, which delivers a voltage which determines the prescribed non-linear relationship, to said voltage supply point, and means connecting the base of said transistor to the junction point of the diode and said remote enD of said series combination.
Claim 7
Dependent Claim
42 words
Integrated circuit as claimed in claim 5, characterized in that the emitter surface area of the transistor of the negative-feedback impedance and the emitter surface areas of the other transistors, reckoned from the diode junction point, increase progressively in the said order.
Claim 8
Dependent Claim
31 words
An integrated circuit as claimed in claim 2 wherein said input terminal is connected to a junction point between the switch and the negative-feedback impedance to supply said input current thereto.
Claim 9
Dependent Claim
45 words
An integrated circuit as claimed in claim 2 including a second diode and a second transistor connected so that the input current is supplied via said second diode to the amplifier input circuit and via the second transistor to the transistor of said negative-feedback impedance.
Claim 10
Dependent Claim
150 words
A non-linear amplifier circuit comprising, an input terminal adapted to receive an input signal, an output terminal adapted to supply an output signal having a non-linear relationship to the input signal, switching means, an amplifier with its input coupled to the input terminal via said switching means and its output coupled to its input via a negative feedback circuit and said switching means, said negative feedback circuit including current source means providing constant current gain from the amplifier input to the output thereby determining the non-linear relationship between the input and output signals, means for coupling the amplifier output to said output terminal, and a storage capacitor connected to the amplifier input independently of the condition of the switching means for storing a voltage determined by the input signal just prior to the opening of said switching means at the start of an operating time interval of the amplifier circuit.
Claim 11
Dependent Claim
150 words
A non-linear amplifier circuit comprising, an input terminal adapted to receive an input signal, an output terminal adapted to supply an output signal having a non-linear relationship to the input signal, switching means, an amplifier with its input coupled to the input terminal via said switching means and its output coupled to its input via a negative feedback circuit and said switching means, said negative feedback circuit including current source means providing constant current gain from the amplifier input to the output thereby determining the non-linear relationship between the input and output signals, means for coupling the amplifier output to said output terminal, and a storage capacitor connected to the amplifier input independently of the condition of the switching means for storing a voltage determined by the input signal just prior to the opening of said switching means at the start of an operating time interval of the amplifier circuit.
Claim 12
Dependent Claim
36 words
An amplifier circuit as claimed in claim 9 wberein said current source means comprises a transistor with its base electrode coupled to the amplifier output and a diode connected across the base-emitter circuit of the transistor.
Claim 13
Dependent Claim
43 words
An amplifier circuit as claimed in claim 10 wherein said current source means further comprises a source of DC voltage coupled to the emitter of the transistor to supply thereto a voltage which determines the non-linear relationship of said input and output signals.
Claim 14
Dependent Claim
40 words
An amplifier circuit as claimed in claim 9 wherein said switching means comprises a diode connected between the input terminal and the amplifier input and a transistor connected between said input terminal and the output of the negative feedback circuit.
Claim 15
Dependent Claim
21 words
An amplifier circuit as claimed in claim 9 wherein said amplifier comprises at least two transistors connected in a Darlington configuration.
Claim 16
Dependent Claim
70 words
An amplifier circuit as claimed in claim 9 for use in a photographic camera or exposure meter and further comprising, a light sensitive element for supplying said input signal to the input terminal, an integrating capacitor coupled to the output terminal, and a trigger circuit coupled to the output terminal and responsive to the output signal thereat to change state at a given value thereof to operate the camera shutter.
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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) | 1977-04-29 | 1977-10-29 | 1978-04-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-04-29 | 1981-10-29 | 1982-04-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-04-29 | 1985-10-29 | 1986-04-30 | $7700.00 | Window Closed / Lapsed |