US3705391A
Expired / Lapsed
US
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Memory system employing capacitance storage means
Assignee: Massachusetts Institute of Technology
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Filing: 1971-10-22
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Granted: 1972-12-05
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Expires: 1991-10-22
Abstract
Abstract Memory apparatus is disclosed wherein digital information in the form of message units is stored in capacitance arrays. Each message unit is converted to an M-level voltage determined by the bit content of the unit and the M-level voltage is transferred to an individual capacitance for storage; once information has been stored, the power to the system can be removed. Appropriately programmed switching enables the storage of many message units sequentially upon individual capacitances. Small physical size requirements of the memory for preferred uses as well as reliability of the switch system are met by field effect transistors which, however, allow charge leakage from the capacitances. It is necessary, therefore, that the memory periodically be updated or restored. Updating is effected by feeding the M-level voltage signals on the capacitances individually and sequentially to one input of a comparator and feeding to the other input thereof an analog signal representing the lowest number of bits greater than or equal to the message unit represented by the displayed signal on the particular capacitance. The analog signal thus determined is then connected to the particular capacitance and/or the digital message unit from which the analog signal is derived can be passed to a readout device. The memory has other uses, one of which, that of image pickup in a solid state camera, is discussed in detail.
Inventors
- 👤 Richard H Baker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 13:54
CPC Classifications
G; G11; G11C; G11C11/00; G11C11/21; G11C11/34; G11C11/40; G11C11/401; G11C11/403; G11C11/404; G11C11/4063; G11C11/407; G11C11/409; G11C11/4096; G11C11/56; G11C11/565; G11C27/00; G11C27/02; G11C27/024; G11C7/00; G11C7/005
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
290 words
Analog apparatus adapted to store digital information comprising a plurality of message units, that comprises, converter means for converting each of the message units to a voltage signal, the level of each signal being determined by the bit content of the message unit represented, capacitance means comprising a plurality of storage capacitances, each to receive and store one said voltage signal, each capacitance making up one leg of a storage array, a field effect transistor serially connected with the capacitance in each leg, switch means which includes the field effect transistors in the legs of the array operable to connect individual storage capacitances of the capacitance means to the converter means to transfer each signal from converter means to a capacitance of the array, control means connected to effect operation of the switch means thereby to effect transfer of a signal from the converter means to the array, an address matrix controlled by said control means and connected to control the field effect transistors to determine which of the storage capacitances of the array shall receive any particular signal, the switch means being further adapted to display the signal on any particular storage capacitance in the array to a comparator, the comparator being connected to receive an output signal from the converter means representative of the lowest number of digital bits greater than or equal to the message unit represented by the displayed signal on said particular storage capacitance thereby to determine the voltage level of the displayed signal in terms of its digital equivalent, said switch means including, in addition to the serially connected field effect transistors, a first switch connecting the capacitance means to the converter means and a second switch connecting the capacitance means to the comParator.
Claim 2
Dependent Claim
290 words
Analog apparatus adapted to store digital information comprising a plurality of message units, that comprises, converter means for converting each of the message units to a voltage signal, the level of each signal being determined by the bit content of the message unit represented, capacitance means comprising a plurality of storage capacitances, each to receive and store one said voltage signal, each capacitance making up one leg of a storage array, a field effect transistor serially connected with the capacitance in each leg, switch means which includes the field effect transistors in the legs of the array operable to connect individual storage capacitances of the capacitance means to the converter means to transfer each signal from converter means to a capacitance of the array, control means connected to effect operation of the switch means thereby to effect transfer of a signal from the converter means to the array, an address matrix controlled by said control means and connected to control the field effect transistors to determine which of the storage capacitances of the array shall receive any particular signal, the switch means being further adapted to display the signal on any particular storage capacitance in the array to a comparator, the comparator being connected to receive an output signal from the converter means representative of the lowest number of digital bits greater than or equal to the message unit represented by the displayed signal on said particular storage capacitance thereby to determine the voltage level of the displayed signal in terms of its digital equivalent, said switch means including, in addition to the serially connected field effect transistors, a first switch connecting the capacitance means to the converter means and a second switch connecting the capacitance means to the comParator.
Claim 3
Dependent Claim
225 words
Analog apparatus adapted to store digital information comprising a plurality of information units, that comprises, converting means for converting each information unit to a voltage signal, the level of each signal being determined by the digital content of the information unit represented, a storage array having a plurality of capacitance charging circuits each comprising a field effect transistor and making up one leg of the storage array, switch means including the field effect transistors in the legs of the array operable to connect individual capacitance charging circuits to the converting means to transfer each signal therefrom to the capacitance charging circuits of the array to store signals therein, and an address matrix connected to control the field effect transistors to determine which capacitance charging circuit of the array shall receive any particular signal, the switch means being further adapted to display the signal on any particular capacitance charging circuit to comparator means, the comparator means being connected to receive an output signal from said particular capacitance charging circuit and to compare it with a digital equivalent generated by the converting means in order to determine the level of signal stored in said particular capacitance charging circuit, said switch means including, in addition to the field effect transistors, first and second switches respectively connecting the capacitance charging circuits to the converting means and the comparator means.
Claim 4
Dependent Claim
225 words
Analog apparatus adapted to store digital information comprising a plurality of information units, that comprises, converting means for converting each information unit to a voltage signal, the level of each signal being determined by the digital content of the information unit represented, a storage array having a plurality of capacitance charging circuits each comprising a field effect transistor and making up one leg of the storage array, switch means including the field effect transistors in the legs of the array operable to connect individual capacitance charging circuits to the converting means to transfer each signal therefrom to the capacitance charging circuits of the array to store signals therein, and an address matrix connected to control the field effect transistors to determine which capacitance charging circuit of the array shall receive any particular signal, the switch means being further adapted to display the signal on any particular capacitance charging circuit to comparator means, the comparator means being connected to receive an output signal from said particular capacitance charging circuit and to compare it with a digital equivalent generated by the converting means in order to determine the level of signal stored in said particular capacitance charging circuit, said switch means including, in addition to the field effect transistors, first and second switches respectively connecting the capacitance charging circuits to the converting means and the comparator means.
Claim 5
Dependent Claim
220 words
Analog apparatus adapted to store digital information comprising a plurality of information units, that comprises, a source of voltage signals each representing an information unit, the level of each signal being determined by the digital content of the information unit represented, a storage array having a plurality of capacitance charging circuits each comprising an electric switching device and making up one leg of the storage array, switch means including the electric switching device in each leg of the array operable to connect individual capacitance charging circuits to said source to transfer each signal therefrom to the capacitance charging circuits of the array for storage therein, and an address matrix connected to control the switching devices to determine which capacitance charging circuit of the array shall receive any particular signal, the switch means being further adapted to display the signal on any particular capacitance charging circuit to comparator means, the comparator means being connected to receive an output signal from said particular capacitance charging circuit and to compare it with a digital equivalent generated by said source in order to determine the level of signal stored in said particular capacitance charging circuit, said switch means including, in addition to the electric switching devices, first and second switches respectively connecting the capacitance charging circuits to said source and to said comparator means.
Claim 6
Dependent Claim
220 words
Analog apparatus adapted to store digital information comprising a plurality of information units, that comprises, a source of voltage signals each representing an information unit, the level of each signal being determined by the digital content of the information unit represented, a storage array having a plurality of capacitance charging circuits each comprising an electric switching device and making up one leg of the storage array, switch means including the electric switching device in each leg of the array operable to connect individual capacitance charging circuits to said source to transfer each signal therefrom to the capacitance charging circuits of the array for storage therein, and an address matrix connected to control the switching devices to determine which capacitance charging circuit of the array shall receive any particular signal, the switch means being further adapted to display the signal on any particular capacitance charging circuit to comparator means, the comparator means being connected to receive an output signal from said particular capacitance charging circuit and to compare it with a digital equivalent generated by said source in order to determine the level of signal stored in said particular capacitance charging circuit, said switch means including, in addition to the electric switching devices, first and second switches respectively connecting the capacitance charging circuits to said source and to said comparator means.
Claim 7
Dependent Claim
227 words
Analog apparatus that comprises, in combination, a storage array having a plurality of capacitance charging circuits each comprising an electric switching device and making up one leg of the storage array, means for charging the individual charging circuits of the array to a voltage level representing a message to be stored, a source of digital information, converting means operable to convert the digital information to an M-level voltage output determined by the bit content thereof, comparator means connected to receive the M-level voltage output as a first input thereto, switch means including the electric switching device in each leg of the array operable to connect individual capacitance charging circuits to the converting means, the switch means being further operable to connect individual capacitance charging circuits of the array to the comparator means as a second input thereto, the comparator means being thereby adapted to receive an output signal from an individual capacitance circuit and to comparE it with a digital equivalent generated by the converting means in order to determine the level of the stored signal in terms of its digital equivalent, said switch means including, in addition to the electric switching devices, first and second switches respectively connecting the capacitance charging circuits to the converting means and the comparator means, and address matrix means connected to control sequencing of the capacitance charging circuits of the array.
Claim 8
Dependent Claim
227 words
Analog apparatus that comprises, in combination, a storage array having a plurality of capacitance charging circuits each comprising an electric switching device and making up one leg of the storage array, means for charging the individual charging circuits of the array to a voltage level representing a message to be stored, a source of digital information, converting means operable to convert the digital information to an M-level voltage output determined by the bit content thereof, comparator means connected to receive the M-level voltage output as a first input thereto, switch means including the electric switching device in each leg of the array operable to connect individual capacitance charging circuits to the converting means, the switch means being further operable to connect individual capacitance charging circuits of the array to the comparator means as a second input thereto, the comparator means being thereby adapted to receive an output signal from an individual capacitance circuit and to comparE it with a digital equivalent generated by the converting means in order to determine the level of the stored signal in terms of its digital equivalent, said switch means including, in addition to the electric switching devices, first and second switches respectively connecting the capacitance charging circuits to the converting means and the comparator means, and address matrix means connected to control sequencing of the capacitance charging circuits of the array.
Claim 9
Dependent Claim
42 words
Analog apparatus as claimed in claim 4 in which the electric switching device in each leg of the array is a field effect transistor and in which each of the capacitance charging circuits comprises a capacitance and a field effect transistor switch.
Claim 10
Dependent Claim
46 words
Analog apparatus as claimed in claim 5 in which each field effect transistor is voltage sensitive and radiation sensitive and in which field effect transistor switches are arranged in a pattern of Y-direction columns and X-direction rows to form the image plane of a solid-state camera.
Claim 11
Dependent Claim
48 words
Analog apparatus as claimed in claim 6 in which each charging circuit is electrically connected across a source of electric potential so that the individual capacitance in each leg of the array can be charged when the corresponding switch in that particular leg of the array is closed.
Claim 12
Dependent Claim
79 words
Analog apparatus as claimed in claim 7 in which the field effect transistor switches are closed either in response to a voltage signal connected to the control electrode thereof or upon being exposed to radiation and which includes a shutter positioned, upon opening, to expose the field effect transistor switches of the pattern to radiation, thereby to charge each individual capacitance of the array to a voltage level determined by the level of the radiation striking said individual capacitance.
Claim 13
Dependent Claim
69 words
Analog apparatus as claimed in claim 8 in which the address matrix means comprises a first address register connected to control the field effect transistor switches in the rows and a second address register connected to control the field effect transistor switches in the columns, thereby to connect any particular capacitance in the pattern to the comparator to relate the charge stored therein in terms of its digital equivalent.
Claim 14
Dependent Claim
25 words
Analog apparatus as claimed in claim 8 in which the converting means is a digital-to-analog converter which acts also as the source of electric potential.
Claim 15
Dependent Claim
65 words
Analog apparatus as claimed in claim 4 in which the electric switching device in each leg of the array includes, in combination, a field effect transistor in parallel with a further field effect transistor and a radiation-sensitive transistor and in which each capacitance charging circuit making up each said leg includes, in addition to said electric switching device, a capacitance in series with said device.
Claim 16
Dependent Claim
51 words
Analog apparatus as claimed in claim 11 in which the capacitance charging circuits are arranged in a pattern of X-direction rows and Y-direction columns to form a matrix, said matrix being located at the image plane of a solid-state camera, the radiation sensitive transistors being positioned to receive any incoming radiation.
Claim 17
Dependent Claim
18 words
Analog apparatus as claimed in claim 12 includes means operable to perform the shutter function of the camera.
Claim 18
Dependent Claim
55 words
Analog apparatus as claimed in claim 13 in which the means to perform the shutter function is a source of pulse voltage connected to each said further field effect transistor, the height of the pulse being the equivalent of the conventional shutter opening and the pulse width being the equivalent of the conventional shutter speed.
Claim 19
Dependent Claim
32 words
Analog apparatus as claimed in claim 4 in which the converting means is a digital-to-analog converter which acts also as a voltage source in said means for charging the individual charging circuits.
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) | 1975-12-05 | 1976-06-05 | 1976-12-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-12-05 | 1980-06-05 | 1980-12-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-12-05 | 1984-06-05 | 1984-12-05 | $7700.00 | Window Closed / Lapsed |