摘要:
A wordline-decode system of a nonvolatile memory array is split into three smaller decoding subsystems (a Read-Mode Decode Subsystem, a Program/Erase-Mode Decode Subsystem and a Segment-Select Decoder Subsystem). The segmented array has small bitline capacitance and requires few input connections to each decoding subsystem. The Read-Mode Decoder circuitry and the Program/Erase-Mode Decoder circuitry are separated, allowing the Read-Mode Decoder circuitry to be desired for high speed access and allowing the Program/Erase-Mode Decoder circuitry to be desired for high voltage operation. Buried-bitline segment-select transistors reduce the area required for those transistors. Erasing may be performed after first checking each row of a segment to determine the present of any over-erased cells. Programming may be performed by allowing the common source-column lines of the selected segment to float and by placing preselected voltages on the appropriate wordline and drain-column line.
摘要:
A circuit for driving a wordline or group of wordlines in a floating-gate type EEPROM cell array includes a read-driver subcircuit for switching positive read voltages, a program-driver subcircuit for switching positive programming voltages and, optionally, a subcircuit for switching negative erasing voltages. The read-driver subcircuit may be constructed using relatively short-channel transistors for relatively high speed operation when connected to high-capacitance wordlines. On the other hand, the program-driver subcircuit may be constructed using relatively long-channel transistors and those long-channel transistors may be located on the memory chip remotely from the memory cells and from the read-driver circuit. P channel isolating transistors are used to isolate unused circuitry during operation. A voltage translator in the program-driver subcircuit has a transistor configuration that lessens the probability that the breakdown voltages of those transistors will be exceeded. A method for programming nonvolatile memory cell arrays is also disclosed.
摘要:
A serial scan path communication architecture includes a plurality of circuits (30), some of which may include a memory (36). A memory access controller (38) is included in circuits with a memory (36) such that serial data may be written to and written from the memories without having to repetitively cycle through multiple TAP read or write operations operations.
摘要:
A serial scan path communication architecture includes a plurality of circuits (30), some of which may include a memory (36). A memory access controller (38) is included on circuits with a memory (36) such that serial data may be written to and written from the memories without having to repetitively cycle through multiple shift operations.
摘要:
A serial scan path communication architecture includes a plurality of circuits (30), some of which may include a memory (36). A memory access controller (38) is included on circuits with a memory (36) such that serial data may be written to and written from the memories without having to repetitively cycle through multiple shift operations.
摘要:
The memory control this invention includes a microprogram-read-only-memory (CROM) containing micro instructions for operation of an integrated-circuit memory, a program counter multiplexer (PCM) to select instructions from the control-read-only-memory, a micro-instruction decoder (MID), a test input multiplexer (TIM) to test control signals, an optional status output register (SOR) to generate control signals, and an optional subroutine stack (SS) to allow function calls. Complex program, erase, and compaction instructions for the integrated-circuit memory are implemented using a relatively small number of control-read-only-memory locations and using a relatively small surface area on the memory chip. Control instructions are easily modified to compensate for process and structure enhancements are made during the production lifetime of an integrated-circuit memory.
摘要:
A method and circuitry for masking data in a memory device are provided, which detect whether at least one failed bit location within the memory device is equal to a corresponding bit within input data. Data is written to the memory device as selectively inverted from the input data based upon whether the failed bit location is equal to the corresponding bit. An inversion bit within the memory device is selectively set to indicate whether the written data is inverted from the input data.
摘要:
Methods, systems and apparatuses for operating a converter or other circuits are disclosed. More particularly, in one embodiment a converter or other circuit can be operated in two modes which may include the count-to-time and time-to count modes to determine an output value corresponding to an input signal. During operation in the count-to-time mode a converter may be operated using a reference signal to determine a number of clock cycles needed until an output corresponds to a scaling factor is reached. During operation of the circuit in the time-to-count mode then, the converter may be operated for this number of clock cycles using the input signal to determine an output. This output may be proportional to the level on the input signal.
摘要:
The device and process of this invention provide for eliminating reading errors caused by over-erased cells by subsequently applying alternating erasing and programming pulses to the cells of an EEPROM array, starting with relatively high-energy-level erasing and programming voltages, decreasing the energy-level of each of the alternating erasing and programming voltages. The initial, relatively high-energy-level pulses should have sufficient energy to cause all of the cells to be programmed and to cause all of the cells to be over-erased. The energy-levels are decreased until electron transfer between floating gate and a source or drain region ceases. As the energy-levels are decreased, the threshold voltage range of the memory cells is compacted. The final threshold voltages are distributed within a preselected narrow range of positive values that are less than a predetermined wordline select voltage.
摘要:
An integrated-circuit memory-array configuration for providing less total access time when used in conjunction with a microprocessor. The configuration includes a line buffer with perhaps 256 latches for storing data, and first and second pipeline circuits for sensing linearity and locality of access information pertaining to the requested data. When used with a microprocessor that is programmed with repeated requests for the same data, a majority of the data requests will be transmitted quickly from the line buffer. If the data requests are not in the line buffer, the configuration furnishes a signal to the microprocessor and the requested data are moved from the floating-gate memory cell array to the line buffer for subsequent transmittal to the microprocessor.