Patents by Inventor Todd Merritt

Todd Merritt has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5875140
    Abstract: A memory device is described which equilibrates and precharges the input/output lines synchronously during a write cycle and asynchronously during a read cycle. During a read cycle, the timing of equilibration and precharge functions are decoupled from the clock signal and asynchronously initiate the equilibrate and precharge functions of the I/O lines in response to a latch signal. The invention initiates the equilibration and precharging of the I/O lines earlier in the access cycle thereby increasing memory access speed.
    Type: Grant
    Filed: November 20, 1997
    Date of Patent: February 23, 1999
    Assignee: Micron Technology, Inc.
    Inventors: Todd A. Merritt, Donald M. Morgan
  • Patent number: 5852371
    Abstract: A voltage level translator is disclosed which translates a CMOS input signal into a CMOS output signal where the low voltage level of the output signal is equal to the high voltage level of the input signal. The voltage level translator is described in an integrated circuit such as memory circuits, including DRAMs. Specifically, the voltage level translator produces an output signal which can be used as a gate voltage on a pre-charge transistor for a booted circuit where the gate voltage need only drop to the high voltage level of the input signal to shut the transistor off. The voltage level translator described, therefore, reduces the time and power required to translate an input signal by limiting the voltage swing of the output signal.
    Type: Grant
    Filed: July 10, 1997
    Date of Patent: December 22, 1998
    Assignee: Micron Technology, Inc.
    Inventors: Todd A. Merritt, Troy A. Manning
  • Patent number: 5841714
    Abstract: A supervoltage circuit has been described which uses a resistor divider as an input stage. The resistor divider decreases the dependancy of the supervoltage trip point on transistor threshold voltages (Vt). The stability of supervoltage trip point is significantly increased over traditional supervoltage circuits using diode connected transistors as an input stage. The supervoltage circuit can be included in any integrated circuit including memory devices.
    Type: Grant
    Filed: October 21, 1996
    Date of Patent: November 24, 1998
    Assignee: Micron Technology, Inc.
    Inventors: Joseph C. Sher, Todd A. Merritt
  • Patent number: 5835422
    Abstract: A memory device (10) for use in an electronic system (12). The system (12) includes a processor (16) that produces a plurality of control signals. The memory device (10) includes a memory array (18) coupled to receive control signals from the processor (18). The memory device (10) also includes a pulse generator (22) that receives at least one of the control signals from the processor (16). The pulse generator (22) includes a latch formed from, for example, a cross coupled pair of NAND-gates (32 and 34). A delayed signal from the latch is coupled to control the reset of the latch such that the latch of the pulse generator (22) outputs a modified control signal for the memory device (10) that has a pulse with a width that is at least as long as the delay.
    Type: Grant
    Filed: April 3, 1997
    Date of Patent: November 10, 1998
    Assignee: Micron Technology, Inc.
    Inventor: Todd A. Merritt
  • Patent number: 5831932
    Abstract: An integrated circuit memory device is described which can operate at high data speeds. The memory device can either store or retrieve data from the memory in a burst access operation. The burst operations latches a memory address from external address lines and internally generates additional memory addresses. An external input is used to terminate and change a burst operation. Circuitry is provided to monitor the external input during burst operations and provide an appropriate control signal.
    Type: Grant
    Filed: August 19, 1997
    Date of Patent: November 3, 1998
    Assignee: Micron Technology, Inc.
    Inventors: Todd Merritt, Brett Williams
  • Patent number: 5831918
    Abstract: The invention is a dynamic random access memory (DRAM) device having an electronic test key fabricated on board and is a method for testing the DRAM. The electronic test key generates a signal which effects a variation in a period of an internal control signal to stress the DRAM during a test mode.
    Type: Grant
    Filed: June 14, 1996
    Date of Patent: November 3, 1998
    Assignee: Micron Technology, Inc.
    Inventors: Todd A. Merritt, Paul S. Zagar
  • Patent number: 5828095
    Abstract: Selected transistors in a charge pump circuit have their associated well regions tied to a capacitor electrode. As a result, the body effect in these devices is reduced, and, consequently, the threshold voltage is reduced as well. With a lower threshold voltage, these transistors allow the charge pump to quickly generate a voltage higher than the positive power supply voltage or a negative substrate bias voltage. In addition, the metal-insulator-semiconductor (MIS) capacitors in the charge pump preferably have their source/drain regions tied to an associated well region, thereby shorting the source/drain/well region junction. Thus, parasitic capacitances associated with these MIS capacitors is significantly reduced, further increasing the speed of the charge pump circuit.
    Type: Grant
    Filed: August 8, 1996
    Date of Patent: October 27, 1998
    Assignee: Micron Technology, Inc.
    Inventor: Todd Merritt
  • Patent number: 5812488
    Abstract: An integrated circuit memory device is described which can operate at high data speeds. The memory device can either store or retrieve data from the memory in a burst access operation. The burst operations latches a memory address from external address lines and internally generates additional memory addresses. A clock signal is provided to synchronize the burst operations. The clock signal is independent of an address latch signal used to latch an external address.
    Type: Grant
    Filed: March 5, 1997
    Date of Patent: September 22, 1998
    Assignee: Micron Technology, Inc.
    Inventors: Paul S. Zagar, Troy A. Manning, Todd Merritt
  • Patent number: 5812462
    Abstract: An integrated circuit clock buffer is described which includes output circuits for generating internal clock signals in response to an externally provided clock signal. The clock buffer includes a latch circuit having a delayed feedback to provide a pulsed signal in response to a transition in the external clock signal. The output circuits have a trip point which is skewed in one direction to detect a rising transition of the pulsed signal, and are skewed in a second direction to detect a falling transition of the pulsed signal. The buffer generates two non-skewed internal clock signals which have sharp rising and falling transitions.
    Type: Grant
    Filed: April 3, 1997
    Date of Patent: September 22, 1998
    Assignee: Micron Technology, Inc.
    Inventor: Todd A. Merritt
  • Patent number: 5811990
    Abstract: A voltage pump and method of driving a node to an increased potential. A periodic input signal is fed into a precharged small capacitor to create a level shifted periodic intermediate potential at an intermediate node. The intermediate node is a supply node to a level translator circuit. The output of the level translator circuit controls the actuation of a pass transistor. When actuated the pass transistor drives a boosted potential to an output node of the voltage pump circuit. In one embodiment the level translator circuit has a delay element which maintains the deactivation of a pull down portion of the level translator circuit until a pull up portion of the level translator circuit is deactivated. A first diode clamp is used to limit the output of the level translator circuit and the boosted potential to within 1 threshold voltage (of the diode clamp) of each other.
    Type: Grant
    Filed: March 13, 1996
    Date of Patent: September 22, 1998
    Assignee: Micron Technology, Inc.
    Inventors: Greg A. Blodgett, Todd A. Merritt
  • Patent number: 5793692
    Abstract: A memory circuit is described which can operate in one of a number of operating modes. The operating mode of the memory circuit can be changed in a non-volatile manner after the memory circuit is packaged to reduce production scrap or meet market demands. Disable circuitry is described which includes an anti-fuse that can be externally selectively blown to disable an operating mode. Control circuitry included in the memory circuit enables a new operating mode after the first operating mode is disable. A method of selectively disabling an operating mode is described. A hierarchical scheme is also described for enabling a new operating mode from a group of operating modes, for example page-mode, extended data output (EDO), or burst EDO.
    Type: Grant
    Filed: March 27, 1997
    Date of Patent: August 11, 1998
    Assignee: Micron Technology, Inc.
    Inventors: Todd Merritt, Troy Manning
  • Patent number: 5790448
    Abstract: A memory chip having an on-chip high voltage generator and charge pump.
    Type: Grant
    Filed: November 1, 1996
    Date of Patent: August 4, 1998
    Assignee: Micron Technology, Inc.
    Inventors: Todd A. Merritt, Kevin Duesman
  • Patent number: 5781486
    Abstract: During compression mode testing of a semiconductor memory device, a memory address is compressed to free up 2 or more bits in the address (e.g., an 11-bit address is compressed to 9-bits, freeing up 2 bits). Redundant element enable circuitry is coupled to one or more pins on a packaged chip that are unused during the compression mode testing. The circuitry receives control signals from external testing circuitry to select between the primary memory array in the chip, and redundant rows and columns of memory in the chip. As a result, during compressed address mode testing of the chip, a full 11-bit word is input to test the circuitry, but where 2 of the 11 bits allow the external circuitry to toggle between, and thereby selectively access, the rows and columns of primary and redundant memory in the chip. Alternatively, the circuitry can also be coupled to a non-connected pin on the packaged chip so as to operate during a non-compression mode testing.
    Type: Grant
    Filed: April 16, 1996
    Date of Patent: July 14, 1998
    Assignee: Micron Technology Corporation
    Inventor: Todd A. Merritt
  • Patent number: 5774412
    Abstract: A dynamic integrated circuit memory is described which has memory cells arranged in rows. The memory rows are selectively accessible using an addressing circuit and local phase lines. Distributed local phase driver circuits are used to drive the local phase lines to a pumped voltage which are coupled to the gate of a memory cell access transistor. Addressing circuitry is provided to selectively address the distributed local phase driver circuits.
    Type: Grant
    Filed: September 9, 1996
    Date of Patent: June 30, 1998
    Assignee: Micron Technology, Inc.
    Inventors: George B. Raad, Todd Merritt, Paul S. Zagar
  • Patent number: 5757703
    Abstract: An integrated circuit memory device is designed to perform high speed data write cycles. An address strobe signal is used to latch a first address. During a burst access cycle the address is incremented internal to the device with additional address strobe transitions. A new memory address is only required at the beginning of each burst access. Read/Write commands are issued once per burst access eliminating the need to toggle the Read/Write control line at the device cycle frequency. A transition of the Read/Write control line during a burst access is used to terminate the burst access and initialize the device for another burst access. Write cycle times are maximized to allow for increases in burst mode operating frequencies. Local logic gates near array sense amplifiers are used to control write data drivers to provide for maximum write times without crossing current during input/output line equilibration periods.
    Type: Grant
    Filed: January 21, 1997
    Date of Patent: May 26, 1998
    Assignee: Micron Technology, Inc.
    Inventors: Todd A. Merritt, Troy A. Manning
  • Patent number: 5745429
    Abstract: A memory device includes an array of memory cells that are arranged in row and columns. A row latch receives a row address and a latch signal and stores the row address in response to a transition of the latch signal. A row decoder is coupled between the latch and the array. In response to a transition of a row address strobe, which occurs a first predetermined time after the transition of the latch signal, the row decoder fires a row of the memory cells that are identified by the row address.
    Type: Grant
    Filed: August 28, 1995
    Date of Patent: April 28, 1998
    Assignee: Micron Technology, Inc.
    Inventors: Timothy B. Cowles, Troy A. Manning, Todd A. Merritt
  • Patent number: 5732036
    Abstract: A memory device is described which equilibrates and precharges the input/output lines synchronously during a write cycle and asynchronously during a read cycle. During a read cycle, the timing of equilibration and precharge functions are decoupled from the clock signal and asynchronously initiate the equilibrate and precharge functions of the I/O lines in response to a latch signal. The invention initiates the equilibration and precharging of the I/O lines earlier in the access cycle thereby increasing memory access speed.
    Type: Grant
    Filed: February 14, 1997
    Date of Patent: March 24, 1998
    Assignee: Micron Technology, Inc.
    Inventors: Todd A. Merritt, Donald M. Morgan
  • Patent number: 5723999
    Abstract: A row address detection circuit includes a fuse bank, including a plurality of fuses connected to a common node. A precharge circuit is connected to bias the common node at a supply voltage. The fuse bank is also coupled through an isolation circuit to a buffer circuit. Selected ones of the fuses are blown in a pattern corresponding to an address of a defective circuit to enable a redundant circuit to be substituted for the defective circuit. The isolation circuit allows the buffer circuit to measure the node voltage to determine if an input to a group of address select lines corresponds to the address of the defective circuit, yet isolates the buffer circuit from the common node to prevent partially blown fuses from placing an excessive load on the buffer circuit. In one embodiment, the isolation circuit is realized with a pair of transistors of opposite channel type coupled for synchronous switching to provide substantial isolation while minimizing voltage drop.
    Type: Grant
    Filed: November 8, 1996
    Date of Patent: March 3, 1998
    Assignee: Micron Technology, Inc.
    Inventor: Todd Merritt
  • Patent number: 5706247
    Abstract: An integrated circuit memory device is described which can operate at high data speeds. The memory device can either store or retrieve data from the memory in a burst access operation. The burst operations latches a memory address from external address lines and internally generates additional memory addresses. An external input is used to terminate and change a burst operation. Circuitry is provided to monitor the external input during burst operations and provide an appropriate control signal.
    Type: Grant
    Filed: November 21, 1996
    Date of Patent: January 6, 1998
    Assignee: Micron Technology, Inc.
    Inventors: Todd Merritt, Brett Williams
  • Patent number: 5706292
    Abstract: The present invention reduces the area on a die required for rows and columns of redundant memory cells by sharing compare circuitry with banks of redundant memory cells based on division of the primary memory array into two or more "planes." Pass gates or multiplexers coupled between at least two banks of fuses and one compare circuit selectively couple the appropriate fuse bank to the compare circuit. Preferably, a bit in the address (e.g., address bit RA9 in a row address word having address bits A0-RA9) is received by and controls the multiplexer to select between the two banks of fuses. Additionally, the planes span blocks of memory in the memory array, where each block is divided by shared sense amplifiers. As a result, while eight lines are coupled to 16 rows or columns, only eight rows or columns will be active at any one time because isolation gates will enable only eight of the 16 rows or columns within two planes of memory.
    Type: Grant
    Filed: April 25, 1996
    Date of Patent: January 6, 1998
    Assignee: Micron Technology, Inc.
    Inventor: Todd A. Merritt