Abstract: A semi-conductor memory device having a wide write data bandwidth is provided with high speed read-write circuitry having data amplifiers that are activated to accelerate amplification of write data signals being driven by write data drivers onto data lines of the cell array of the device during memory write cycles, as well as activated to amplify read data signals on the data lines during memory read cycles. Moreover, the data amplifiers are activatedin a self-timed manner. In one embodiment, the device is further provided with a read data buffer that is constituted with a regenerative latch and an input stage, and a write data buffer having multiple entries. The input stage of the read data buffer isolates or couples the regenerative latch to the data lines depending on whether the data lines are in a pre-charged state or not.

Abstract: A non-volatile memory (NVM) system includes a NVM cell having: a semiconductor region having a first conductivity type; a gate dielectric layer located over the semiconductor region; a gate electrode located over the gate dielectric layer; a source region and a drain region of a second conductivity type, opposite the first conductivity type, located in the semiconductor region and aligned with the gate electrode; a crown electrode having a base that contacts the gate electrode and walls that extend vertically from the base region, away from the gate electrode; a dielectric layer located over the crown electrode, wherein the dielectric layer extends over at least interior surfaces of the walls; and a plate electrode located over the dielectric layer, wherein the plate electrode extends over at least interior surfaces of the walls.

Abstract: A non-volatile memory (NVM) cell is fabricated by slightly modifying a conventional logic process. The NVM cell is fabricated by forming the gate electrode of an access transistor from a first conductive layer, and then forming a capacitor structure that contacts the gate electrode. In one embodiment, the capacitor structure is fabricated by forming a crown electrode of a capacitor structure from a second conductive layer, forming a dielectric layer over the crown electrode, and then forming an plate electrode over the dielectric layer from a third conductive layer. The crown electrode contacts the gate electrode, thereby providing an electrical connection between these electrodes. A first set of thermal cycles are performed during the formation of the capacitor structure. After the capacitor structure has been formed, P+ and/or N+ ion implantations are performed, thereby forming shallow junctions on the chip (e.g., a drain region of the access transistor).

Abstract: A semi-conductor memory device having a wide write data bandwidth is provided with high speed read-write circuitry having data amplifiers that are activated to accelerate amplification of write data signals being driven by write data drivers onto data lines of the cell array of the device during memory write cycles, as well as activated to amplify read data signals on the data lines during memory read cycles. Moreover, the data amplifiers are activated in a self-timed manner. In one embodiment, the device is further provided with a read data buffer that is constituted with a regenerative latch and an input stage, and a write data buffer having multiple entries. The input stage of the read data buffer isolates or couples the regenerative latch to the data lines depending on whether the data lines are in a pre-charged state or not.

Abstract: A method and structure for implementing a DRAM memory array as a second level cache memory in a computer system. The computer system includes a central processing unit (CPU), a first level SRAM cache memory, a CPU bus coupled to the CPU, and a second level cache memory which includes a DRAM array coupled to the CPU bus. When accessing the DRAM array, row access and column decoding operations are performed in a self-timed asynchronous manner. Predetermined sequences of column select operations are then performed in a synchronous manner with respect to a clock signal. A widened data path is provided to the DRAM array, effectively increasing the data rate of the DRAM array. By operating the DRAM array at a higher data rate than the CPU bus, additional time is provided for precharging the DRAM array. As a result, the precharging of the DRAM array is transparent to the CPU bus. A structure and method control the refresh and internal operations of the DRAM array.

Abstract: A memory device which utilizes a plurality of memory modules coupled in parallel to a master I/O module through a single directional asymmetrical signal swing (DASS) bus. This structure provides an I/O scheme having symmetrical swing around half the supply voltage, high through-put, high data bandwidth, short access time, low latency and high noise immunity. The device utilizes improved column access circuitry including an improved address sequencing circuit and a data amplifier within each memory module. A resynchronization circuit allows the device to operate either synchronously and asynchronously using the same pins. Each memory module has independent address and command decoders to enable independent operation so that each memory module is activated by commands on the DASS bus only when a memory access operation is performed within the particular memory module. Redundant memory modules are included to replace defective memory modules, and replacement can be carried out through commands on the DASS bus.

Abstract: A memory system including a DRAM array, a read buffer, a write buffer and an input/output (I/O) interface. The read buffer and write buffer are coupled between the DRAM array and the I/O interface. When an external transaction involves multiple pieces of data in consecutive address locations, such as a burst access, parallel operations are performed in the DRAM array and the I/O interface. In a burst read transaction, all the data in the burst transaction is pre-fetched from the DRAM memory into the read buffer in one memory cycle. After the read data has been pre-fetched, the DRAM array is available for a refresh operation. The DRAM array can therefore be refreshed while the burst read data is sequentially transferred from the read buffer to the I/O interface. In a burst write transaction, multiple burst write data values are written to the write buffer over multiple I/O cycles. This burst write data is not retired to the DRAM array until the next write transaction.

Abstract: A memory system is provided that controls a memory that must be refreshed, such as DRAM, in a manner that does not require extensive external control. In one embodiment, the memory system includes a memory controller and a memory block that are coupled by a system bus. The memory block includes an array of memory cells that must be periodically refreshed to maintain valid data. The memory block also includes a refresh control circuit that refreshes the memory cells during idle cycles of the memory array. The memory controller monitors the number of idle cycles on the system bus during a predetermined refresh period. If the number of monitored idle cycles is less than a predetermined required number of idle cycles, the memory controller forces the required number of idle cycles on the system bus. As a result, the memory controller ensures that there will always be enough idle cycles in which the memory array can be refreshed.

Abstract: A graphics sub-system having a 2-D graphics accelerator, a 3-D graphics accelerator and an embedded DRAM memory. The embedded DRAM memory serves as a frame buffer memory and/or a temporary storage memory for the 2-D graphics accelerator. The embedded DRAM memory also serves as a cache memory for the 3-D graphics accelerator or an external central processing unit (CPU). The embedded DRAM memory is logically divided into a plurality of independent banks, thereby resulting in a relatively fast average memory cycle time. More specifically, the embedded DRAM memory processes one transaction per clock cycle for accesses with no bank conflicts. The memory access time for any transaction (e.g., a bank-conflict access) is no greater than the memory cycle time plus the memory access time minus 1 clock cycle.

Abstract: A memory system that includes a dynamic random access memory (DRAM) cell, a word line, and a CMOS word line driver fabricated using a conventional logic process. The word line driver is controlled to provide a positive boosted voltage and a negative boosted voltage to the word line, thereby controlling access to the DRAM cell. A positive boosted voltage generator is provided to generate the positive boosted voltage, such that this voltage is greater than V.sub.dd but less than V.sub.dd plus the absolute value of a transistor threshold voltage V.sub.t. Similarly, a negative boosted voltage generator is provided to generate a negative boosted voltage, such that this voltage is less than V.sub.SS by an amount less than V.sub.t. A coupling circuit is provided between the word line driver and one of the positive or negative boosted voltage generators. The coupling circuit couples the word line driver to the selected one of the positive or negative boosted word line generators only when the word line is activated.

Abstract: A method and structure for implementing a DRAM memory array as a second level cache memory in a computer system. The computer system includes a central processing unit (CPU), a first level SRAM cache memory, a CPU bus coupled to the CPU, and a second level cache memory which includes a DRAM array coupled to the CPU bus. When accessing the DRAM array, row access and column decoding operations are performed in a self-timed asynchronous manner. Predetermined sequences of column select operations are then performed in a synchronous manner with respect to a clock signal. A widened data path is provided to the DRAM array, effectively increasing the data rate of the DRAM array. By operating the DRAM array at a higher data rate than the CPU bus, additional time is provided for precharging the DRAM array. As a result, the precharging of the DRAM array is transparent to the CPU bus. A structure and method control the refresh and internal operations of the DRAM array.

Abstract: A memory system including a DRAM array, a read buffer, a write buffer and an input/output (I/O) interface. The read buffer and write buffer are coupled between the DRAM array and the I/O interface. When an external transaction involves multiple pieces of data in consecutive address locations, such as a burst access, parallel operations are performed in the DRAM array and the I/O interface. In a burst read transaction, all the data in the burst transaction is pre-fetched from the DRAM memory into the read buffer in one memory cycle. After the read data has been pre-fetched, the DRAM array is available for a refresh operation. The DRAM array can therefore be refreshed while the burst read data is sequentially transferred from the read buffer to the I/O interface. In a burst write transaction, multiple burst write data values are written to the write buffer over multiple I/O cycles. This burst write data is not retired to the DRAM array until the next write transaction.

Abstract: A method and apparatus for handling the refresh of a DRAM array so that the refresh has no effect on the external access. This allows an SRAM compatible memory to be built from DRAM (or 1-Transistor) cells. By utilizing the unused external access time for performing the infrequent memory refresh, there is no penalty on the peak bandwidth requirement of the memory array.

Abstract: A structure and method of implementing a cache memory for a multi-processor system. The cache memory includes a main memory which is coupled to a main memory bus. A plurality of processors can also be coupled to the main memory bus. The main memory includes a plurality of RAM circuit module memory banks. The sense amplifiers of a predetermined number of banks are used as cache memory (i.e., sense amplifier cache lines). The number of banks used with sense amplifiers activated is substantially less than the total number of banks. The banks which are not used as cache memory are kept in a precharged state.

Abstract: A method and structure for performing a screen refresh operation in a video processing system which includes a frame buffer memory and a display controller coupled to a system bus. A status bit memory is used to store status bits which represent the repetitive characteristics of pixel data stored in the frame buffer memory. The status bits are provided to the display controller. In response, the display controller determines whether to provide pixel data by regenerating pixel data previously retrieved from the frame buffer memory or by accessing the frame buffer memory.

Abstract: A system and method for wafer scale integration optimized for medium die size integrated circuits by interconnecting a large number of separate memory (or other circuit) modules on a semiconductor wafer so as to electrically exclude both defective modules and defective interconnect/power segments, and include operative modules and interconnect/power segments. A set of discretionary connections are associated with each of the separate modules and interconnect/power segments and such connections are made (or broken) after a module or interconnect or power segment is tested. A power supply network is set up by combining operative power segments. A bidirectional bus is set up by combining operative interconnect segments to connect to each operative modules. This bidirectional bus consists of one or more hierarchies for speed, power and yield considerations. Each module is assigned an identity code using discretionary connections.

Abstract: A bus line termination circuit for limiting signal swing on a bus line to a reduced CMOS-swing. The termination circuit includes a switch and a first resistor connected in series between the bus line and a first voltage supply, and a second resistor connected in series between the bus line and a second voltage supply. The values of the first and second resistors are selected such that a termination voltage equal to the average of the first and second supply voltages exists on the bus line. The bus line is further connected to a receiver circuit having a threshold voltage equal to the average of the first and second supply voltages. The switch is controlled to disconnect the bus line from the first voltage supply when the bus line is in an inactive state. In an alternative embodiment, a termination circuit includes one or more voltage regulator circuits, each being coupled to the first and second voltage supplies. A clamping resistor coupled each voltage regulator circuit to the bus line.

Abstract: A method and structure for implementing a DRAM memory array as a second level cache memory in a computer system. The computer system includes a central processing unit (CPU), a first level SRAM cache memory, a CPU bus coupled to the CPU, and a second level cache memory which includes a DRAM array coupled to the CPU bus. When accessing the DRAM array, row access and column decoding operations are performed in a self-timed asynchronous manner. Predetermined sequences of column select operations are then performed in a synchronous manner with respect to a clock signal. The DRAM array is operated at a higher frequency than the frequency of the CPU bus clock signal, thereby reducing the access latency of the DRAM array. By operating the DRAM array at a higher frequency than the CPU bus, additional time is provided for precharging the DRAM array. As a result, the precharging of the DRAM array is transparent to the CPU bus.

Abstract: A method and structure for generating a boosted word line voltage for a memory array, such as a DRAM array. To ensure that an adequate voltage is applied to the word line of the memory array during write operations, the word line driver circuit is connected to a boost voltage generator which provides a substantially constant, regulated voltage which is boosted to a level which is approximately equal to the V.sub.cc supply voltage plus the threshold voltage of the memory cell pass transistor. A bias voltage generator provides a negative voltage which is used to bias the substrate of the memory array. The boosted voltage generator and the bias voltage generator can be operated in response to the same clock signal used to operate the memory array. A latch-up prevention circuit is provided to ensure that the word line driver circuit does not latch-up during power-on before an adequate boost voltage has been established.

Abstract: A computer unified memory architecture (UMA) system and method which includes a unified memory which is partitioned into a main memory and a main frame buffer memory, as well as a separate expansion frame buffer memory. Together, the main frame buffer memory and the expansion frame buffer memory form an entire frame buffer memory. The UMA system performs a display refresh operation by alternately accessing the main frame buffer memory and the expansion frame buffer memory. Because the display data bandwidth is split between the main frame buffer memory and the expansion frame buffer memory, the data bandwidth of the unified memory is effectively increased, thereby enabling higher system performance. The expansion frame buffer memory has a relatively small capacity, thereby retaining much of the cost benefit of a UMA system.