Abstract: A multiport memory having a serial access memory device. The serial access memory device is comprised of serial memory cells and a serial port. The serial memory cells store electrical information which is accessed serially. The information in a selected cell is developed in a sampling circuit to create an amplified signal which may be coupled to the serial port. The amount of signal developed in the sampling circuit is externally controlled by a user when the user controls the frequency of an external control signal. The frequency of the external control signal determines the length of time the signal is developed and therefore the amplitude of the signal. In one embodiment an isolation circuit isolates or couples the sampling circuit to a serial information node and alternately isolates or couples the sampling circuit to the serial port. The external control signal controls the signal development by controlling the time the sampling circuit is coupled to the serial information nodes.

Abstract: A multiport memory having a serial input port receives serial data into a pipeline. The pipeline is emptied in response to a transfer signal at a time before the parallel transfer of data from a serial to parallel conversion register into memory. The pipeline in one embodiment includes in serial connection an input latch, a first isolation gate, a write register, a second isolation gate, an I/O bus, and means for equilibrating the I/O bus. The pipeline is controlled by write control logic so that the pipeline is emptied while equilibration of digit lines is being disabled. In a video random access memory (VRAM) embodiment, a tap counter and hold register specify the next position for serial access to the serial access register. These elements are controlled by write control logic in response to a transfer signal and a serial clock signal to allow the tap counter to increment while emptying the pipeline. When the pipeline is already empty, no increment takes place.

Abstract: The invention is a circuit and method for maintaining a negative potential, with respect to the digit line potential, on non-selected wordlines.

Abstract: A video RAM having isolated array sections for providing write function that will not affect other array sections. The whole VRAM memory array does not have to be completely read before writing new pixel information to particular array section. At least two separate VRAM activities can be performed simultaneously to different parts of the array. Specifically, to write to one particular section of an array and to and for refreshing other parts of the VRAM. The overall read and write sequences can be shorter. When a particular pixel or memory cell has to be modified or update, only an associated SAM to the particular cell will be activated. This SAM will now only affect the column lines associated with that section of the array containing the activated SAM.

Abstract: A memory in which a portion of a digit line is isolated from the remainder of the digit line during a write cycle has improved performance. In the conventional architecture of a memory device, cells are arranged in rows and columns and a sense amplifier is employed for a pair of columns, located between a pair of complementary digit lines. An embodiment of the present invention in this architecture provides improved means for isolating the sense amplifier during a write cycle.

Abstract: Serial clock cycle time for a serial read operation in a semiconductor memory is reduced by partitioning the read operation into a sensing operation, a counter operation and an output operation, and conducting all three operations simultaneously in a pipelined fashion. To carry out the new method, the memory effectively is pipelined by providing a read register (92) between the sensing flip-flop (90) and the output latch/driver (96), and by isolating the address counter (48) from the address decoder circuitry (56) by inserting an isolation buffer (52). Additionally, the serial access time is reduced by conducting a look-ahead load (72) of a first tap address at the conclusion of a read transfer cycle, without waiting for the serial clock signal (SC) to begin the read cycle.

Abstract: A DRAM or VRAM integrated circuit memory of the divided bit line design includes a bit line pair extending from a column decoder to a SAM. An N-sense amplifier divides the bit line pair into two pairs of bit halves. The N-sense amplifier is connected to each of the bit line halves through an isolation transistor. A P-sense amplifier is connected across each pair of the bit line halves. Since a P-sense amplifier is associated with each pair of bit line halves, the P-sense amplifier never has to pull through isolation transistors, and thus the isolation transistors can be high threshold transistors, eliminating the natural threshold mask step in fabrication. The two P-sense amplifiers separate the bit line voltages faster, thereby decreasing crossing current and saving power, and pull the bit lines to full high voltage levels.

Abstract: A DRAM or VRAM integrated circuit memory of the divided bit line design includes a first bit line pair divided into a first pair of bit line halves and a second pair of bit line halves, and second bit line pair divided into a third pair of bit line halves and a fourth pair of bit line halves. A row decoder addresses a row associated with the first pair of bit line halves during a first time period, addresses a row associated with the second pair of bit line halves in a second time period, addresses a row associated with the third pair of bit line halves in the first time period, and addresses a row associated with the fourth pair of bit line halves in the second time period. The access topology is thus asymmetric with respect to a column decoder connected to the second and third pairs of bit line halves.

Abstract: The specification discloses preferred circuits and methods for performing a block write in a video random access memory circuit (VRAM). The VRAM has a plurality of memory registers, an address bus, and a data bus. The VRAM also has a multiple write register circuit with a plurality of write registers. During write register load cycles, data is written from the data bus to individual write registers which are specified by addresses received on the address bus. During a block write cycle, data is written from an individual write register to a selected block of memory registers; the block having a predefined number of memory registers within a row. The block of memory registers is specified by memory register base address received on the address bus. The memory register base address is the address of the first memory register in the block of memory registers.

Abstract: A DRAM or VRAM integrated circuit memory of the divided bit line design includes a bit line pair extending from a column decoder to a SAM. An N-sense amplifier divides the bit line pair into two pairs of bit line halves. The N-sense amplifier is connected to each of the bit line halves through an isolation transistor. A P-sense amplifier is connected across each pair of the bit line halves. The timing signals enabling and disabling the isolation transistors and the P-sense amplifiers are designed so that during an access of the bit line halves nearest the data port, the isolation of the N-sense amplifier and the associated P-sense amplifier from the bit line halves distal from the data port is extended through the P-sense amplifier cycle and into the precharge cycle, thereby charging only the bit line halves nearest the port and saving power.

Abstract: There is an integrated circuits that has an improved N-channel sense amplifier that increases the digital one and zero range. The invention spikes the lower voltage digit line closer to ground shortly before equilibrating with the higher voltage digit line.

Abstract: A low current substrate bias generator for regulating the potential of a substrate layer of an integrated circuit includes a sense element having an input for sensing the potential of the substrate. The substrate bias gates a PMOS transistor connected in a source follower configuration, being serially connected to a load element at its output and connected to ground at its drain. The PMOS transistor output is a control signal. The control signal is complemented by an inverter and the complement activates a charge pump that is coupled to the substrate layer or well that is desired to be regulated. The sense element includes the PMOS transistor and the load element. The sense element does not deplete or enhance the substrate potential but only provides substrate bias sensing and a subsequent control signal for activation and deactivation of the charge pump.