US5537349A
Expired / Lapsed
US
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Memory in integrated circuit form with improved reading time
Assignee: STMicroelectronics SA
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Filing: 1994-12-21
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Granted: 1996-07-16
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Expires: 2014-12-21
Abstract
Abstract A random-access memory with an accelerated access time. One or more of the preliminary operations of the sequence of operations carried out for accessing the memory are anticipated by performing the anticipated operation or operations during the end of a sequence of a previous memory access. The anticipated operation is preferably that of the deselection of the bit lines of the memory.
Inventors
- 👤 Jean Devin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 20:55
CPC Classifications
G; G11; G11C; G11C7/00; G11C7/12; G11C16/00; G11C16/02; G11C16/06; G11C16/24; G11C16/26
Claims Analysis
Total Claims: 46
Claim 1
Independent Claim
150 words
An integrated circuit memory having a cell that is connected to at least one select line, the integrated circuit memory comprising: a preactivation circuit, connected to the at least one select line, that places the at least one select line into a preactivation state, the preactivation state being either of a high impedance or a first voltage; a precharging circuit, connected to the at least one select line, that precharges the at least one select line to a second voltage that is different from the first voltage; an access circuit, controlled by an access signal, that accesses the cell, the access of the cell including one of a read, write, and read-write of an electrical state of the cell; and a delay circuit, activated by the access circuit, that places the at least one select line into the preactivation state with a calibrated delay following an access of the cell.
Claim 2
Dependent Claim
150 words
An integrated circuit memory having a cell that is connected to at least one select line, the integrated circuit memory comprising: a preactivation circuit, connected to the at least one select line, that places the at least one select line into a preactivation state, the preactivation state being either of a high impedance or a first voltage; a precharging circuit, connected to the at least one select line, that precharges the at least one select line to a second voltage that is different from the first voltage; an access circuit, controlled by an access signal, that accesses the cell, the access of the cell including one of a read, write, and read-write of an electrical state of the cell; and a delay circuit, activated by the access circuit, that places the at least one select line into the preactivation state with a calibrated delay following an access of the cell.
Claim 3
Dependent Claim
67 words
The integrated circuit memory of claim 1, wherein the at least one select line includes a plurality of bit lines, and wherein the integrated circuit memory further includes: a plurality of cells respectively coupled to the plurality of bit lines; and a connection circuit that connects the plurality of bit lines together when the preactivation circuit places the at least one select line into the preactivation state.
Claim 4
Dependent Claim
38 words
The integrated circuit memory of claim 1, wherein the delay circuit comprises a cascade of series-connected inverter circuits and a capacitor, the capacitor being connected between a reference voltage and a midpoint between two of the inverter circuits.
Claim 5
Dependent Claim
33 words
The integrated circuit memory of claim 1, wherein the integrated circuit memory has a nominal cycle time, and wherein the delay circuit produces a first calibrated delay equal to the nominal cycle time.
Claim 6
Dependent Claim
24 words
The integrated circuit memory of claim 1, further including a storage circuit that saves the electrical state of the cell during a read access.
Claim 7
Dependent Claim
33 words
The integrated circuit memory of claim 5, wherein the integrated circuit memory has a nominal cycle time, and wherein the delay circuit produces a delay that is greater than the nominal cycle time.
Claim 8
Dependent Claim
25 words
The integrated circuit memory of claim 1, wherein the preactivation state is a state of high impedance, and the memory cell is an EPROM cell.
Claim 9
Dependent Claim
23 words
The integrated circuit memory of claim 1, wherein the preactivation state is the first voltage, and the memory cell is an EEPROM cell.
Claim 10
Dependent Claim
20 words
The integrated circuit memory of claim 1, wherein the at least one select line comprises at least one bit line.
Claim 11
Dependent Claim
20 words
The integrated circuit memory of claim 1, wherein the at least one select line comprises at least one word line.
Claim 12
Dependent Claim
33 words
The integrated circuit memory of claim 2, wherein the integrated circuit memory has a nominal cycle time, and wherein the delay circuit produces a first calibrated delay equal to the nominal cycle time.
Claim 13
Dependent Claim
52 words
The integrated circuit memory of claim 11, wherein the delay circuit further produces a second calibrated delay during a read access that is greater than the nominal cycle time; and wherein the integrated circuit memory further includes a storage circuit that stores the electrical state of the cell during the read access.
Claim 14
Dependent Claim
38 words
The integrated circuit memory of claim 12, wherein the delay circuit comprises a cascade of series-connected inverter circuits and a capacitor, the capacitor being connected between a reference voltage and a midpoint between two of the inverter circuits.
Claim 15
Dependent Claim
29 words
The integrated circuit memory of claim 4, wherein the delay circuit further produces a second calibrated delay that is greater than the nominal cycle time during a read access.
Claim 16
Independent Claim
82 words
A method for controlling an access cycle of a memory, the memory having a cell connected to a select line, the cell having an electrical state, the method comprising the steps of: A precharging the select line to a precharged state; B activating the select line to an activated state wherein the electrical state of the cell is accessed; and C after performing step B, placing the select line into a preactivated state that is different from the precharged and activated states.
Claim 17
Independent Claim
82 words
A method for controlling an access cycle of a memory, the memory having a cell connected to a select line, the cell having an electrical state, the method comprising the steps of: A precharging the select line to a precharged state; B activating the select line to an activated state wherein the electrical state of the cell is accessed; and C after performing step B, placing the select line into a preactivated state that is different from the precharged and activated states.
Claim 18
Dependent Claim
53 words
The method of claim 15, Wherein step B includes activating the select line to read the electrical state of the cell, and wherein the method further includes the steps of: prior to performing step C, storing the state of the cell; and after performing step C, writing the stored state to the cell.
Claim 19
Dependent Claim
36 words
The method of claim 16, wherein the memory includes a plurality of cells respectively coupled to a plurality of select lines, and wherein step B includes a step of connecting the plurality of select lines together.
Claim 20
Dependent Claim
17 words
The method of claim 17, wherein step C includes setting the select line to a predetermined voltage.
Claim 21
Dependent Claim
19 words
The method of claim 16, wherein step C includes placing the select line into a state of high impedance.
Claim 22
Dependent Claim
36 words
The method of claim 15, wherein the memory includes a plurality of cells respectively coupled to a plurality of select lines, and wherein step B includes a step of connecting the plurality of select lines together.
Claim 23
Dependent Claim
19 words
The method of claim 15, wherein step C includes placing the select line into a state of high impedance.
Claim 24
Dependent Claim
17 words
The method of claim 15, wherein step C includes setting the select line to a predetermined voltage.
Claim 25
Dependent Claim
103 words
A memory having a select line and a cell coupled together, the memory comprising: a precharge circuit, coupled to the select line, that precharges the select line to a precharged state; an access circuit that places the cell into an access state during an access clock cycle, the access state being one of a read, write, and read-write state of the cell; and first means for placing the select line into a preactivated state during the access clock cycle and after the cell has been placed into the access state, the preactivated state being different from the precharged state and the access state.
Claim 26
Dependent Claim
103 words
A memory having a select line and a cell coupled together, the memory comprising: a precharge circuit, coupled to the select line, that precharges the select line to a precharged state; an access circuit that places the cell into an access state during an access clock cycle, the access state being one of a read, write, and read-write state of the cell; and first means for placing the select line into a preactivated state during the access clock cycle and after the cell has been placed into the access state, the preactivated state being different from the precharged state and the access state.
Claim 27
Dependent Claim
40 words
The memory of claim 23, wherein the access state is a read state, and wherein the memory further includes means for storing the state of the cell prior to the first means placing the select line into the preactivated state.
Claim 28
Dependent Claim
44 words
The memory of claim 24, wherein the memory further includes: a plurality of select lines respectively coupled to a plurality of cells; and means for connecting the plurality of select lines together when the first means places the select line into the preactivated state.
Claim 29
Dependent Claim
20 words
The memory of claim 25, wherein the first means includes means for setting the select line to a predetermined voltage.
Claim 30
Dependent Claim
22 words
The memory of claim 24, wherein the first means includes means for placing the select line into a state of high impedance.
Claim 31
Dependent Claim
44 words
The memory of claim 23, wherein the memory further includes: a plurality of select lines respectively coupled to a plurality of cells; and means for connecting the plurality of select lines together when the first means places the select line into the preactivated state.
Claim 32
Dependent Claim
22 words
The memory of claim 23, wherein the first means includes means for placing the select line into a state of high impedance.
Claim 33
Dependent Claim
20 words
The memory of claim 23, wherein the first means includes means for setting the select line to a predetermined voltage.
Claim 34
Dependent Claim
44 words
The memory of claim 30, wherein the memory further includes: a plurality of select lines respectively coupled to a plurality of cells; and means for connecting the plurality of select lines together when the first means places the select line into the preactivated state.
Claim 35
Independent Claim
128 words
A method for accessing an electrical state of a memory cell during an access cycle of a memory, the memory cell being coupled to a select line having a precharge state, an access state and a preactivation state, the preactivation state being either of a high impedance and a predetermined voltage, the method comprising the steps of: A setting the state of the select line to the precharge state during the access cycle; B following step A, changing the state of the select line from the precharge state to the access state to access the electrical state of the memory cell; and C following step B, changing the state of the select line from the access state to the preactivation state before the end of the access cycle.
Claim 36
Independent Claim
128 words
A method for accessing an electrical state of a memory cell during an access cycle of a memory, the memory cell being coupled to a select line having a precharge state, an access state and a preactivation state, the preactivation state being either of a high impedance and a predetermined voltage, the method comprising the steps of: A setting the state of the select line to the precharge state during the access cycle; B following step A, changing the state of the select line from the precharge state to the access state to access the electrical state of the memory cell; and C following step B, changing the state of the select line from the access state to the preactivation state before the end of the access cycle.
Claim 37
Dependent Claim
30 words
The method of claim 32, wherein step B further includes the steps of: storing the electrical state of the memory cell; and rewriting the electrical state to the memory cell.
Claim 38
Dependent Claim
47 words
The method of claim 33, wherein the memory includes a plurality of select lines and a plurality of memory cells, the plurality of memory cells being respectively coupled to the plurality of select lines, and wherein step C further includes connecting the plurality of select lines together.
Claim 39
Dependent Claim
47 words
The method of claim 32, wherein the memory includes a plurality of select lines and a plurality of memory cells, the plurality of memory cells being respectively coupled to the plurality of select lines, and wherein step C further includes connecting the plurality of select lines together.
Claim 40
Dependent Claim
162 words
A circuit for accessing the electrical state of a memory cell during an access cycle of a memory, the memory cell being coupled to a select line having a precharge state, an access state and a preactivation state, the preactivation state being either of a high impedance and a predetermined voltage, the circuit comprising: first means for setting the state of the select line to the precharge state at a first time during the access cycle; second means for changing the state of the select line from the precharge state to the access state to access the electrical state of the memory cell at a second time during the access cycle; and third means for changing the state of the select line from the access state to the preactivation state at a third time during the access cycle, wherein the first time precedes the second time during the access cycle, and the second time precedes the third time during the access cycle.
Claim 41
Dependent Claim
162 words
A circuit for accessing the electrical state of a memory cell during an access cycle of a memory, the memory cell being coupled to a select line having a precharge state, an access state and a preactivation state, the preactivation state being either of a high impedance and a predetermined voltage, the circuit comprising: first means for setting the state of the select line to the precharge state at a first time during the access cycle; second means for changing the state of the select line from the precharge state to the access state to access the electrical state of the memory cell at a second time during the access cycle; and third means for changing the state of the select line from the access state to the preactivation state at a third time during the access cycle, wherein the first time precedes the second time during the access cycle, and the second time precedes the third time during the access cycle.
Claim 42
Dependent Claim
31 words
The circuit of claim 36, wherein the second means further includes: means for storing the electrical state of the cell; and means for rewriting the electrical state to the memory cell.
Claim 43
Dependent Claim
50 words
The circuit of claim 37, wherein the memory includes a plurality of memory cells and a plurality of select lines, the plurality of select lines being respectively coupled to the plurality of memory cells, and wherein the third means further includes means for connecting the plurality of select lines together.
Claim 44
Dependent Claim
50 words
The circuit of claim 36, wherein the memory includes a plurality of memory cells and a plurality of select lines, the plurality of select lines being respectively coupled to the plurality of memory cells, and wherein the third means further includes means for connecting the plurality of select lines together.
Claim 45
Dependent Claim
25 words
The integrated circuit memory of claim 5, wherein the preactivation state is a state of high impedance, and the memory cell is an EPROM cell.
Claim 46
Dependent Claim
23 words
The integrated circuit memory of claim 5, wherein the preactivation state is the first voltage, and the memory cell is an EEPROM cell.
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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) | 1999-07-16 | 2000-01-15 | 2000-07-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-07-16 | 2004-01-15 | 2004-07-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-07-16 | 2008-01-15 | 2008-07-16 | $7700.00 | Window Closed / Lapsed |