Patents Assigned to Enhanced Memory Systems, Inc.
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Patent number: 6646928Abstract: A packet-based dynamic random access memory (“DRAM”) device incorporating an on-chip row register cache which is functional to reduce the initial device latency, reduce “page miss” latency and reduce chip layout overhead by reducing bus sizes and the level of required multiplexing and demultiplexing compared to Rambus® Direct RDRAM™ (trademarks, of Rambus, Inc., Mountain View, Calif.) devices. In accordance with an embodiment of the present invention, the row register cache and a separate write path, or bus, are integrated into each DRAM bank serving to improve DRAM latency parameters and pipeline burst rate. The row register holds “read” data during burst reads to allow hidden precharge and same bank activation to minimize “page miss” latency. The faster pipelined burst rate simplifies Direct RDRAM multiplexer/demultiplexer logic and reduces internal data bus size by 50%.Type: GrantFiled: January 16, 2003Date of Patent: November 11, 2003Assignee: Enhanced Memory Systems, Inc.Inventor: David Bondurant
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Patent number: 6549472Abstract: A packet-based dynamic random access memory (“DRAM”) device incorporating an on-chip row register cache which is functional to reduce the initial device latency, reduce “page miss” latency and reduce chip layout overhead by reducing bus sizes and the level of required multiplexing and demultiplexing compared to Rambus® Direct RDRAM™ (trademarks, of Rambus, Inc., Mountain View, Calif.) devices. In accordance with an embodiment of the present invention, the row register cache and a separate write path, or bus, are integrated into each DRAM bank serving to improve DRAM latency parameters and pipeline burst rate. The row register holds “read” data during burst reads to allow hidden precharge and same bank activation to minimize “page miss” latency. The faster pipelined burst rate simplifies Direct RDRAM multiplexer/demultiplexer logic and reduces internal data bus size by 50%.Type: GrantFiled: February 21, 2002Date of Patent: April 15, 2003Assignee: Enhanced Memory Systems, Inc.Inventor: David Bondurant
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Patent number: 6538928Abstract: A memory architecture uses shared sense amplifiers (18-23) and a centralized cache (26-29) that contains M bits. The memory architecture also includes a global bus (31) connecting the sense amplifiers and the centralized cache. The global bus includes n bits, and n<M bits are transferred in M/n cycles to the centralized cache.Type: GrantFiled: October 11, 2000Date of Patent: March 25, 2003Assignee: Enhanced Memory Systems Inc.Inventor: Kenneth J. Mobley
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Patent number: 6501698Abstract: A method and system for hiding DRAM cycle time behind burst read and write accesses. A combined read and write data transfer area interacts with a set of sense amplifiers to accelerate read and write cycles. By independently isolating the read data transfer areas and the write data transfer areas, data can be transferred (1) from the DRAM array to the read data transfer areas, (2) from the write data transfer areas to the DRAM array, and (3) from the write data transfer areas to the read data transfer areas.Type: GrantFiled: November 1, 2000Date of Patent: December 31, 2002Assignee: Enhanced Memory Systems, Inc.Inventor: Kenneth J. Mobley
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Patent number: 6373751Abstract: A packet-based dynamic random access memory (“DRAM”) device incorporating an on-chip row register cache which is functional to reduce the initial device latency, reduce “page miss” latency and reduce chip layout overhead by reducing bus sizes and the level of required multiplexing and demultiplexing compared to Rambus® Direct RDRAM™ (trademarks, of Rambus, Inc., Mountain View, Calif.) devices. In accordance with an embodiment of the present invention, the row register cache and a separate write path, or bus, are integrated into each DRAM bank serving to improve DRAM latency parameters and pipeline burst rate, The row register holds “read” data during burst reads to allow hidden precharge and same bank activation to minimize “page miss” latency. The faster pipelined burst rate simplifies Direct RDRAM multiplexer/demultiplexer logic and reduces internal data bus size by 50%.Type: GrantFiled: May 15, 2000Date of Patent: April 16, 2002Assignee: Enhanced Memory Systems, Inc.Inventor: David Bondurant
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Patent number: 6347357Abstract: An enhanced DRAM contains embedded row registers in the form of latches. The row registers are adjacent to the DRAM array, and when the DRAM comprises a group of subarrays, the row registers are located between DRAM subarrays. When used as on-chip cache, these registers hold frequently accessed data. This data corresponds to data stored in the DRAM at a particular address. When an address is supplied to the DRAM, it is compared to the address of the data stored in the cache. If the addresses are the same, then the cache data is read at SRAM speeds. The DRAM is decoupled from this read. The DRAM also remains idle during this cache read unless the system opts to precharge or refresh the DRAM. Refresh or precharge occur concurrently with the cache read. If the addresses are not the same, then the DRAM is accessed and the embedded register is reloaded with the data at that new DRAM address.Type: GrantFiled: October 30, 1998Date of Patent: February 12, 2002Assignee: Enhanced Memory Systems, Inc.Inventors: Ronald H. Sartore, Kenneth J. Mobley, Donald G. Carrigan, Oscar Frederick Jones
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Patent number: 6330636Abstract: A double data rate (“DDR”) synchronous dynamic random access memory (“SDRAM”) device incorporating a static random access memory (“SRAM”) cache per memory bank that provides effectively double peak data bandwidth, optimizes sustained bandwidth and improves bus efficiency as compared with conventional DDR SDRAM devices. The memory device disclosed provides effectively faster basic DRAM memory latency parameters, faster page “hit” latency, faster page “miss” latency and sustained bandwidth on random burst reads, faster read-to-write latency and write-to-read latency, hidden precharge, hidden bank activate latency, hidden refresh and hidden write precharge during a read “hit”.Type: GrantFiled: January 29, 1999Date of Patent: December 11, 2001Assignee: Enhanced Memory Systems, Inc.Inventors: David W. Bondurant, Michael Peters, Kenneth J. Mobley
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Patent number: 6301183Abstract: An enhanced bus turnaround integrated circuit dynamic random access memory (“DRAM”) device of particular utility in providing maximum DRAM performance while concomitantly affording a device with may be readily integrated into systems designed to use zero bus turnaround (“ZBT”), or pipeline burst static random access memory (“SRAM”) devices. The enhanced bus turnaround DRAM device of the present invention provides much of the same benefits of a conventional ZBT SRAM device with a similar pin-out, timing and function set while also providing improvements in device density, power consumption and cost approaching that of straight DRAM memory.Type: GrantFiled: July 27, 2000Date of Patent: October 9, 2001Assignee: Enhanced Memory Systems, Inc.Inventors: David Bondurant, David Fisch, Bruce Grieshaber, Kenneth Mobley, Michael Peters
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Patent number: 6278646Abstract: A memory device, and an associated method, contain at least two memory arrays and a single decoder shared by the memory arrays. When data is to be accessed from selected memory locations of one of the memory arrays, the non-selected memory array is inactivated by precharging the bit lines of the array to a common voltage with the data input and/or output buses for that array, thereby allowing the decoder to select the inactive array without harm, and thereby preventing the need for additional decoder circuitry to discriminate between the arrays. The array containing the selected memory locations remains active, thereby permitting accessing of the memory locations therein.Type: GrantFiled: March 23, 2000Date of Patent: August 21, 2001Assignee: Enhanced Memory Systems, Inc.Inventor: Kenneth J. Mobley
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Patent number: 6249840Abstract: A multi-bank ESDRAM, and an associated method, provides for the caching of data accessed from any DRAM memory array of the multi-bank ESDRAM device to any SRAM cache register of the ESDRAM device. Execution of a read operation is carried out using an existing command set utilized to read data from conventional ESDRAM devices.Type: GrantFiled: October 23, 1998Date of Patent: June 19, 2001Assignee: Enhanced Memory Systems, Inc.Inventor: Michael Peters
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Patent number: 6151236Abstract: An enhanced bus turnaround integrated circuit dynamic random access memory ("DRAM") device of particular utility in providing maximum DRAM performance while concomitantly affording a device with may be readily integrated into systems designed to use zero bus turnaround ("ZBT"), or pipeline burst static random access memory ("SRAM") devices. The enhanced bus turnaround DRAM device of the present invention provides much of the same benefits of a conventional ZBT SRAM device with a similar pin-out, timing and function set while also providing improvements in device density, power consumption and cost approaching that of straight DRAM memory. Through the provision of a "Wait" pin, the enhanced bus turnaround device of the present invention can signal the system memory controller when additional wait states must be added yet still provide virtually identical data access time performance to that of ZBT SRAM for all Read and Write operations with a burst length of four or greater.Type: GrantFiled: February 29, 2000Date of Patent: November 21, 2000Assignee: Enhanced Memory Systems, Inc.Inventors: David Bondurant, David Fisch, Bruce Grieshaber, Kenneth Mobley, Michael Peters
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Patent number: 6141281Abstract: A technique for reducing element disable fuse pitch requirements in an integrated circuit device incorporating replaceable elements wherein each group of replaceable elements contains a circuit which enables an element group within a chained set to determine whether it is the "leftmost" (or first) element used within the set by monitoring the state of an adjacent node. The node will transition to a logic "low" level if (and only if) a fuse within the set, (and located to the left of the node) is "blown" (or opened). By then multiplexing signals to select one or more elements within the first group and additional signals to select one or more elements within the second group, the necessary determination can be made to disable any given pair of elements based on the state of the fuses, the adjacent nodes and the additional signals.Type: GrantFiled: April 29, 1998Date of Patent: October 31, 2000Assignee: Enhanced Memory Systems, Inc.Inventors: Kenneth J. Mobley, Steve W. Ash
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Patent number: 6064620Abstract: A memory device, and an associated method, contains at least two memory arrays and a single decoder shared by the memory arrays. When data is to be accessed from selected memory locations of one of the memory arrays, the non-selected memory array is inactivated by precharging the bit lines of the array to a common voltage with the data input and/or output buses for that array, thereby allowing the decoder to select the inactive array without harm, and thereby preventing the need for additional decoder circuitry to discriminate between the arrays. The array containing the selected memory locations remains active, thereby permitting accessing of the memory locations therein.Type: GrantFiled: July 8, 1998Date of Patent: May 16, 2000Assignee: Enhanced Memory Systems, Inc.Inventor: Kenneth J. Mobley
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Patent number: 6055192Abstract: A word line boost-on-writes technique for a dynamic random access memory device in which the word lines are initially boosted upon opening of a page in the memory array and then again following each write command, or following a predetermined number of write cycles in the case of a burst write, in order that the precharge cycle can proceed without delay due to the boost operation. Each boost is applied for a limited duration so that the overall precharge time is not affected.Type: GrantFiled: September 3, 1998Date of Patent: April 25, 2000Assignee: Enhanced Memory Systems, Inc.Inventor: Kenneth J. Mobley
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Patent number: 5991851Abstract: An enhanced digital signal processing random access memory device utilizing a highly density DRAM core memory array integrated with an SRAM cache and internal refresh control functionality which may be provided in an integrated circuit package which is pin-compatible with industry standard SRAM memory devices. The memory device provides a high speed memory access device of particular utility in conjunction with DSP processors with performance equivalent to that of SRAM memory devices but requiring a significantly small die size which allows for the provision of greater effective memory capacity per die area. The internal refresh functionality of the device provides for all refresh operations to the DRAM memory array to occur transparently to the device user and provides control signals alerting the associated controller when refresh operations are being performed.Type: GrantFiled: May 2, 1997Date of Patent: November 23, 1999Assignee: Enhanced Memory Systems, Inc.Inventors: Michael Alwais, Kenneth J. Mobley
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Patent number: 5963481Abstract: An integrated circuit device, and an associated method, in which a logic element, such as a central processing unit, is embedded together with an EDRAM EDRAM (Enhanced Dynamic Random Access Memory) upon a common substrate die. A memory bus interconnects the EDRAM and the logic element. Data thruput rates of memory read and write operations are permitted to be of increased rates relative to the rates permitted of conventional, discrete devices.Type: GrantFiled: June 30, 1998Date of Patent: October 5, 1999Assignee: Enhanced Memory Systems, Inc.Inventors: Michael Alwais, Michael Peters
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Patent number: 5887272Abstract: An enhanced DRAM contains embedded row registers in the form of latches. The row registers are adjacent to the DRAM array, and when the DRAM comprises a group of subarrays, the row registers are located between DRAM subarrays. When used as on-chip cache, these registers hold frequently accessed data. This data corresponds to data stored in the DRAM at a particular address. When an address is supplied to the DRAM, it is compared to the address of the data stored in the cache. If the addresses are the same, then the cache data is read at SRAM speeds. The DRAM is decoupled from this read. The DRAM also remains idle during this cache read unless the system opts to precharge or refresh the DRAM. Refresh or precharge occur concurrently with the cache read. If the addresses are not the same, then the DRAM is accessed and the embedded register is reloaded with the data at that new DRAM address.Type: GrantFiled: July 3, 1997Date of Patent: March 23, 1999Assignee: Enhanced Memory Systems, Inc.Inventors: Ronald H. Sartore, Kenneth J. Mobley, Donald G. Carrigan, Oscar Frederick Jones
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Patent number: 5875451Abstract: A computer system with a hybrid main memory which includes both EDRAM and DRAM, with a DRAM cache provided within a designated portion of the EDRAM portion of the main memory. Read requests are handled by copying data being read from DRAM into a cache portion of EDRAM under the direction of a pseudo cache controller and decoder which converts the DRAM address to a EDRAM address corresponding to the cache location of EDRAM. Read "hit" requests are responded to by reading data directly from the cache portion of EDRAM. Write requests to DRAM are, for purposes of cache coherency when a copy of the address being written to is present in the EDRAM cache portion, accomplished by writing data both to DRAM and overwriting the stale data existing in the cache portion of EDRAM.Type: GrantFiled: March 14, 1996Date of Patent: February 23, 1999Assignee: Enhanced Memory Systems, Inc.Inventor: James Dean Joseph
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Patent number: 5835442Abstract: An EDRAM device includes an EDRAM memory array on a semiconductor chip. A row enable signal generator and a column address latch signal generator are provided on the same semiconductor chip for generating row enable and column address latch signals for application to the EDRAM memory array.Type: GrantFiled: March 22, 1996Date of Patent: November 10, 1998Assignee: Enhanced Memory Systems, Inc.Inventors: James Dean Joseph, Dion Nickolas Heisler, Doyle James Heisler