摘要:
A memory system couples command, address or write data signals from a memory controller to a memory device and read data signals from the memory device to the memory controller. A respective strobe generator circuit in each of the memory controller and the memory device each generates an in-phase strobe signal and a quadrature strobe signal. Command, address or write data signals stored in respective output latches in the memory controller are clocked by the in-phase signals from the internal strobe generator circuit. These command, address or write data signals are latched into input latches in the memory device by the quadrature strobe signal coupled from the memory controller to the memory device. In substantially the same manner, read data signals are coupled from the memory device to the memory controller using the in-phase and quadrature strobe signals generated by the internal strobe generator circuit.
摘要:
A method of synchronizing counters in two different clock domains within a memory device is comprised of generating a start signal for initiating production of a running count of clock pulses of a read clock signal in a first counter downstream of a locked loop and delaying the input of the start signal to a second counter upstream of the locked loop to delay the initiation of a running count of control clock pulses by an amount equal to a predetermined delay. Another disclosed method is for controlling the output of data from a memory device comprising deriving from an external clock signal a control clock for operating an array of storage cells and a read clock, both the control clock and the read clock being comprised of clock pulses. A start signal is generated for initiating production of a running count of the read clock pulses in a first counter. The start signal may be produced when a locked loop achieves a lock between the read clock and the control clock. The input of the start signal to a second counter is delayed to delay the initiation of a running count of the control clock pulses. The delay, which may be expressed as an integer number of clock cycles, may be equal to an input/output delay of the memory device. The method may be modified by inputting the start signal to an offset counter before initiating the production of the running count of the read clock pulses in the first counter. The offset counter may be loaded with a value equal to a programmed latency less a synchronization overhead. Once the running counts are initiated, each time a read command is received, a then current value of the running count of control clock pulses from the second counter is latched or held. The held value is compared to the running count of read clock pulses from the first counter, with the read clock signal being used to output data in response to the comparison. Apparatus for implementing the disclosed methods are also disclosed. Because of the rules governing abstracts, this abstract should not be used to construe the claims.
摘要:
A cache memory system and method includes a DRAM having a plurality of banks, and it also includes 2 SRAMs each having a capacity that is equal to the capacity of each bank of the DRAM. In operation, data read from a bank of the DRAM are stored in one of the SRAMs so that repeated hits to that bank are cached by reading from the SRAM. In the event of a write to a bank that is being refreshed, the write data are stored in one of the SRAMs. After the refresh of the bank has been completed, the data stored in the SRAM are transferred to the DRAM bank. A subsequent read or write to a second DRAM bank undergoing refresh and occurring during the transfer of data from an SRAM to the DRAM is stored in either the second bank or the other SRAM.
摘要:
A 256 Meg dynamic random access memory is comprised of a plurality of cells organized into individual arrays, with the arrays being organized into 32 Meg array blocks, which are organized into 64 Meg quadrants. Sense amplifiers are positioned between adjacent rows in the individual arrays while row decoders are positioned between adjacent columns in the individual arrays. In certain of the gap cells, multiplexers are provided to transfer signals from I/O lines to data lines. A datapath is provided which, in addition to the foregoing, includes array I/O blocks, responsive to the datalines from each quadrant to output data to a data read mux, data buffers, and data driver pads. The write data path includes a data in buffer and data write muxes for providing data to the array I/O blocks. A power bus is provided which minimizes routing of externally supplied voltages, completely rings each of the array blocks, and provides gridded power distribution within each of the array blocks. A plurality of voltage supplies provide the voltages needed in the array and in the peripheral circuits. The power supplies are organized to match their power output to the power demand and to maintain a desired ratio of power production capability and decoupling capacitance. A powerup sequence circuit is provided to control the powerup of the chip. Redundant rows and columns are provided as is the circuitry necessary to logically replace defective rows and columns with operational rows and columns. Circuitry is also provided on chip to support various types of test modes.
摘要:
A method and apparatus for managing the variable timing of internal clock signals derived from an external clock signal in order to compensate for uncertainty and variations in the amount of read clock back timing relative to data flow to achieve a specified read latency. A reset signal is generated at DRAM initialization and starts an first counter, which counts external clock cycles, and is also passed through the slave delay line of the delay lock loop to start a second counter. The counters run continuously once started and the difference in count values represent the internal delay as an external clock signal passes through the delay lock loop to produce an internal read clock signal. An internal read latency value is used to offset either counter to account for the internal read latency of the DRAM circuit. Once the non-offset counter is equivalent to the offset counter, read data is placed on an output line with a specified read latency and synchronized with the external read clock.
摘要:
A 256 Meg dynamic random access memory is comprised of a plurality of cells organized into individual arrays, with the arrays being organized into 32 Meg array blocks, which are organized into 64 Meg quadrants. Sense amplifiers are positioned between adjacent rows in the individual arrays while row decoders are positioned between adjacent columns in the individual arrays. In certain of the gap cells, multiplexers are provided to transfer signals from I/O lines to data lines. A datapath is provided which, in addition to the foregoing, includes array I/O blocks, responsive to the datalines from each quadrant to output data to a data read mux, data buffers, and data driver pads. The write data path includes a data in buffer and data write muxes for providing data to the array I/O blocks. A power bus is provided which minimizes routing of externally supplied voltages, completely rings each of the array blocks, and provides gridded power distribution within each of the array blocks. A plurality of voltage supplies provide the voltages needed in the array and in the peripheral circuits. The power supplies are organized to match their power output to the power demand and to maintain a desired ratio of power production capability and decoupling capacitance. A powerup sequence circuit is provided to control the powerup of the chip. Redundant rows and columns are provided as is the circuitry necessary to logically replace defective rows and columns with operational rows and columns. Circuitry is also provided on chip to support various types of test modes.
摘要:
There is provided a bi-level bit line architecture. Specifically, a DRAM memory cell and cell array are provided that allow for six square feature area (6F2) cell sizes and avoid the signal to noise problems. Uniquely, the digit lines are designed to lie on top of each other like a double-decker overpass road. Additionally, this design allows each digit line to be routed on both conductor layers, for equal lengths of the array, to provide balanced impedance. Now noise will appear as a common mode noise on both lines, and not as differential mode noise that would degrade the sensing operation. Furthermore, digit to digit coupling is nearly eliminated because of the twist design.
摘要:
The present invention is directed to an integrated circuit device having a memory cell for storing a data and refresh circuitry for refreshing that data in the memory cell. In one illustrative embodiment, the device comprises a memory cell having a storage element, a read/write access device, and a refresh access device. A read/write digit line is coupled to the read/write access device, and a refresh digit line is coupled to the refresh access device. A sense amplifier is coupled to the read/write digit line, and input/output circuitry is coupled to the read/write digit line. A refresh sense amplifier is coupled to the refresh digit line. The memory cell is constructed in such a way as to provide a large charge storage capacity in a relatively small, compact area.
摘要:
A 256 Meg dynamic random access memory is comprised of a plurality of cells organized into individual arrays, with the arrays being organized into 32 Meg array blocks, which are organized into 64 Meg quadrants. Sense amplifiers are positioned between adjacent rows in the individual arrays while row decoders are positioned between adjacent columns in the individual arrays. In certain of the gap cells, multiplexers are provided to transfer signals from I/O lines to data lines. A datapath is provided which, in addition to the foregoing, includes array I/O blocks, responsive to the datalines from each quadrant to output data to a data read mux, data buffers, and data driver pads. The write data path includes a data in buffer and data write muxes for providing data to the array I/O blocks. A power bus is provided which minimizes routing of externally supplied voltages, completely rings each of the array blocks, and provides gridded power distribution within each of the array blocks. A plurality of voltage supplies provide the voltages needed in the array and in the peripheral circuits. The power supplies are organized to match their power output to the power demand and to maintain a desired ratio of power production capability and decoupling capacitance. A powerup sequence circuit is provided to control the powerup of the chip. Redundant rows and columns are provided as is the circuitry necessary to logically replace defective rows and columns with operational rows and columns. Circuitry is also provided on chip to support various types of test modes.
摘要:
A system and memory including a circuit for setting write latency and a write/valid indicator. Time margin regions are established just after the first or leading edge and just before the second or following edge of the preamble of the clock signal such that a latency setting will be found unacceptable if it causes a write enable signal to transition in either of these regions. A write/valid indicator circuit creates the start and end time margin regions by delaying either the clock signal or the write enable signal and comparing their timing with the timing of the undelayed write enable signal or clock signal respectively.