Abstract: A substantially noise-free address input buffer for an asynchronous device, such as a static random access memory (SRAM). The input buffer generates both a logical true and complement representation of an address input signal and includes timing circuitry to place the logical true and complement signals in the same deasserting logical state for a predetermined period of time prior to asserting either the logical true signal or the logical complement signal, in response to a signal edge transition appearing on the address input signal. The input buffer further includes edge transition detection (ETD) circuitry for generating an initialization signal in response to the generation of the logical true and complement signals.

Abstract: A method and apparatus are disclosed for controlling the operation of a polyphase motor, and particularly to determining whether the motor is spinning. The method and apparatus include initially sensing an electrical characteristic of a single phase winding of the motor. Having sensed values of the electrical characteristic, a determination is made as to whether or not the motor's rotor is spinning. Upon a determination that the rotor is not spinning, a spin-up operation is performed to bring the spin of the rotor to operable spin speeds. Otherwise, a resynchronization operation is performed.

Abstract: A method and circuit are disclosed for replacing defective columns of flash memory cells in a flash memory device. The circuit includes a plurality of sets of storage elements, each set of storage elements being capable of identifying a single addressed column of memory cells is to be replaced or a main column line and regular columns of memory cells associated therewith to be replaced. In the event a main column line and the associated regular columns are identified for replacement by a set of storage elements, the set additionally indicates whether the regular columns are regular columns in a single block of memory cells or multiple blocks. Redundancy circuitry performs the replacement operation during a memory access operation based upon the information stored in the sets of storage elements.

Abstract: A memory device having a first and a second memory section, the first and the second memory sections being coupled to bit lines. The second memory section may include at least one fuse. The first memory section includes a volatile memory and the second memory section includes a non-volatile memory. The volatile memory may be static or dynamic random access memory. The memory device may further include a control circuit connected to the at least one fuse to provide for prelaser testing.

Abstract: A method and system are disclosed for dynamically changing the priority of memory requests to access a memory device in a disk drive system. In particular, the disk drive system includes a hard disk controller having a processing element for performing various operations and a buffer for providing an interface to a memory device, such as a random access memory. The buffer includes arbitration block to prioritize memory requests to access the memory device. A priority modification block is included to modify the assigned priorities so that the priority assigned to a pending memory request submitted by the processing element is increased. The priority modification block triggers the modification of priorities upon the occurrence of an event, such as the reception of an interrupt by the processing element or a memory request submitted by the processing element timing out.

Abstract: A random access memory cell and fabrication method therefor are disclosed. The random access memory cell includes a first and a second pull-down transistor cross-coupled such that a control terminal of the first pull-down transistor is connected to a conduction terminal of the second pull-down transistors, and the control terminal of the second pull-down transistor is connected to the conduction terminal of the first pull-down transistor. A first pass gate transistor is coupled between the conduction terminal of the first transistor and a first bit line of a bit line pair, and a second pass gate transistor is coupled between the conduction terminal of the second transistor and a second bit line of the bit line pair.

Abstract: A test circuit and method are disclosed for testing memory cells of a ferroelectric memory device having an array of ferroelectric memory cells. The test circuitry is coupled to the column lines, for selectively sensing voltage levels appearing on the column lines and providing externally to the ferroelectric memory device an electrical signal representative of the sensed voltage levels. In this way, ferroelectric memory cells exhibiting degraded performance may be identified.

Abstract: A method and circuit are disclosed for replacing defective columns of flash memory cells in flash memory device. The circuit includes a plurality of sets of storage elements, each set of storage elements being capable of identifying at least one column of memory cells in any block of memory cells as being defective. The circuit further includes control circuitry for replacing an addressed column of memory cells with a redundant column of memory cells upon an affirmative determination that a set of storage elements identifies the addressed column of memory cells as being defective.

Abstract: A circuit and method are disclosed for monitoring the voltage level of an electrical signal, such as an unregulated power supply. The circuit includes a comparator that compares the electrical to the voltage reference and generates an output having a value that is based upon the comparison. A oscillation suppression circuit receives the output of the comparator and generates an output signal that follows the output of the comparator once the output of the comparator remains stable and in the same logic state for a predetermined of time.

Abstract: A user configurable dual bank memory device is disclosed. The memory device includes a plurality of core banks of memory cells and a set of storage elements having stored therein configuration information. The configuration may be used to configure or group core banks of memory cells together to form a dual bank memory device. The memory device includes control circuitry for preventing a memory read operation from being completed in a core bank or user-configured dual bank in which an ongoing memory modify (program or erase) operation is being performed. The memory device further includes a first set of sense amplifiers dedicated to performing sense amplification only during memory read operations, and a second set of sense amplifiers dedicated to performing sense amplification only during memory modify operations.

Abstract: A method and system are disclosed for spinning the spindle motor of a disk drive from a stationary state to an operable state that is suitable for performing a memory access operation. The method and system include energizing the polyphase motor in a first predetermined commutation phase; detecting whether a zero crossing of a back electromotive force (bemf) signal corresponding to the first predetermined commutation phase occurs; sensing whether the polyphase motor advanced to a next successive commutation phase relative to the first predetermined commutation phase; and performing an acceleration procedure to accelerate the speed of the polyphase motor towards a desired speed based upon a detected zero crossing of the bemf signal and an affirmative determination that the polyphase motor advanced to a next successive commutation phase relative to the first predetermined commutation phase.

Abstract: A memory device having redundancy is disclosed. The memory device includes an array of memory cells organized into rows and columns of memory cells, each row of memory cells including a plurality of addressable memory cells and redundant memory cells, the array of memory cells including row lines and column lines, each row line being coupled to memory cells in a distinct row of memory cells, each column line being coupled to memory cells in a distinct column of memory cells, and column input/output lines. The memory device further includes a redundancy circuitry for selectively coupling column lines to column input/output lines of the array of memory cells and selectively decoupling at least one column line from the column input/output lines, based upon an address value received by the memory device during a memory access operation.

Abstract: A sense amplifier circuit and method are disclosed for nonvolatile memory devices, such as flash memory devices. The sense amplifier circuit includes a current source that is configurable to source any of at least two nonzero current levels in the sense amplifier circuit. The sense amplifier circuit is controlled by control circuitry in the nonvolatile memory device so that each sense amplifier circuit sources a first current level during the precharge cycle of a memory read operation, and a second current level, greater than the first current level, during the memory cell sense operation. In this way, the sense amplifier circuit consumes less power during the memory read operation without an appreciable loss in performance.

Abstract: A method is disclosed for controlling the write head of a magnetic disk storage device. The method includes sinking current from the first terminal of the write head and sourcing current to the second terminal of the write head substantially simultaneously with sinking current from the first terminal so that a first steady state voltage level appears on the first terminal of the write head and a second steady state voltage level appears on the second terminal thereof that are approximately at a midpoint between a high reference voltage level and a low reference voltage level. The common mode voltage of the write head is substantially constant over time.

Abstract: A method and circuit are disclosed for controlling the write head of a magnetic disk storage device. The circuit includes a pull-up device coupled to a terminal of the write head, a current sink circuit which is coupled to the write head terminal and a bootstrap circuit coupled to the current sink circuit. When reversing the direction of current flow through the write head so that current is drawn from the write head from the write head terminal, the bootstrap circuit and the current sink circuit are activated. When the current in the write head nears and/or slightly surpasses the desired destination current level, the bootstrap circuit is deactivated and the pull-up device is thereafter immediately activated for a predetermined period of time.

Abstract: A method and circuit are disclosed for controlling the write head of a magnetic disk storage device. The circuit includes a pull-up device and a current sink circuits coupled to each terminal of the write head, for selectively sourcing current to and sinking current from the write head, respectively. A clamp device is coupled to each write head terminal to selectively clamp the write head terminals to steady state intermediate voltage levels. The circuit further includes a control circuit for individually activating the pull-up devices, the current sink circuits and the clamp devices. In particular, when reversing the direction of current flow through the write head from a first direction in which current is provided to the write head via the write head terminal to a second direction in which current is drawn from the write head from the write head terminal, the appropriate pull-up device is activated for a predetermined period of time.

Abstract: A method and device are disclosed for controlling a polyphase motor having a plurality of windings. The device includes a memory device having stored therein data representing a predetermined driving profile, and driver circuit for driving the windings of the polyphase motor based upon the data provided by the memory unit. A feedback control loop is included having an input connected to a selected winding of the polyphase motor and providing an address signal to the memory device that is based upon a current level of the selected winding at around the time the back electromotive force (bemf) signal corresponding thereto crosses a zero reference, for controlling current provided to the windings by the driver circuit so that, for each winding, the current provided thereto is substantially in phase with a back electromotive force (emf) signal corresponding to the winding.

Abstract: A content addressable memory (CAM) includes a voltage power supply input and an enable input. An enable control circuit is connected to the enable input, and operates to compare an external voltage to an enable reference voltage. If the external voltage drops below the enable reference voltage, the enable control circuit drives the enable input to place the CAM into a low current, stand-by mode of operation. A voltage supply back-up circuit is connected to the voltage power supply input, and operates to compare the external voltage to a supply reference voltage. If the external voltage drops below the supply reference voltage, the voltage supply back-up circuit switches the voltage power supply input for the CAM from the external voltage input to a battery back-up. As an alternative, the voltage power supply input for the CAM includes a separate power input for a CAM array, and the switch causes only that separate power input for the CAM array to be powered from the battery back-up.

Abstract: A current sense amplifier including a transconductance amplifier to measure a current passing through a sense resistor and generate a reference current indicative of the measured current. A current mirror circuit is connected to the transconductance amplifier and receives the reference current for amplification to generate an amplified output current. A cascode circuit is connected serially to the current mirror circuit to boost an output impedance for the amplifier at the output of the generated amplified output current. The current mirror circuit and cascode circuit of the current sense amplifier are each formed from a pair of transistors sharing a common control node, with the transistors realized using with bipolar or MOS technology.

Abstract: A modular semiconductor power device has a conductive member consisting of an alumina plate to which copper layers are soldered on opposite sides. A chip is soldered to one of these layers and the other of these layers is soldered in turn to a metal heat sink. The chip is connected to respective copper strips which, in turn, are soldered to thermal strips originally forming part of a frame so that, after the device is encapsulated in a synthetic resin, the connecting members of the frame can be cut away to leave free ends of the latter strips exposed.