Sandisk Technologies Inc.

Sandisk 3d LLC

Yingchang Chen

Chang Hua Siau

Anurag Nigam

Tz-Yi Liu

Jeffrey Koon Yee Lee

Pankaj Kalra

Ali K Al-Shamma

Chandrasekhar R Gorla

Yukeun Sim

Tianhong Yan

Gopinath Balakrishnan

Jingwen Ouyang

Jeffrey Lee

Yadhu Vamshi Vancha

Xiaowei Jiang

Seungpil Lee

James B Hart

Marco Cazzaniga

Henry Zhang

Thomas Yan

Chun-Ju Chu

Chandrasekhar Gorta

Xiaoxia Wu

A sense amplifier for a memory circuit is presented that can sense a selected memory cell in either a first sensing mode, in which current from the selected memory cell flows from the memory cells into the sense amplifier, or a second sensing mode, in which current is discharged from the sense amplifier through the selected memory cell. In the first sensing mode, current from a selected memory cell is conducted through cascaded PMOS transistors to charge a sensing node, with the resultant voltage level on the sensing node used to determine the result of the sensing operation.

Sense amplifier for bidirectional sensing of memory cells of a non-volatile memory

A circuit or associated system or apparatus includes a first transistor, a second transistor, a first switch, a second switch, a first current source, and a third switch. The first transistor is configured to sample a first current of a control line. The second transistor is configured to apply a second current to the control line. The second transistor is also configured to match the second current to the first current. The first switch is connected in series between a control terminal of the first transistor and a control terminal of the second transistor. The second switch is connected in series between the second transistor and the control line. The third switch is connected in series between the first current source and the control line.

Fast voltage compensation without feedback

One or more control lines other than those used to activate a non-volatile memory cell may be used to sense a data value of the cell. For example, an apparatus may include a selection circuit that selects, based on an address corresponding to a non-volatile memory cell included an array of non-volatile memory cells, a word line coupled to the non-volatile memory cells to activate the non-volatile memory cell. An amplifier circuit may sense a data value stored in the non-volatile memory cell based on a sense signal having a voltage level based on voltage levels of one or more other word lines of the array of non-volatile memory cells. In another example, a data value of a non-volatile memory cell coupled to a word line may be sensed based on the voltage levels of one or more dummy sense lines within the array.

Sensing memory cells using array control lines

A sense circuit includes memory cell characterization circuitry, storage circuitry, switching circuitry, and bit line biasing circuitry. The sense circuit is configured to perform a sense operation to sense a characterization of a memory cell. During a pre-charge phase, the memory cell characterization circuitry and the bit line biasing circuitry set differential voltages in the storage circuitry to levels dependent on input offset voltages according to certain polarities. The storage circuitry maintains the differential voltages during the sense phase, allowing the memory cell characterization circuitry to cancel output the input offset voltages when generating output voltages used to identify a characterization of the memory cell. The memory cell characterization circuitry also generates its output voltage based on a reference current through a reference bit line. Doing so may allow the memory cell characterization circuitry to cancel out background noise current generated on the bit line during the sense operation.

Sense amplifier with non-ideality cancellation

A system may include a controller, a data receiving circuit, and a plurality of banks. The banks may send data to the data receiving circuit via a common data bus. The controller may control the communication of the data to the receiving circuit by sending control signals and clock signals to the banks. Relative lengths of control signal paths and clock signal paths may be directly related to each other and inversely related to relative lengths of data paths.

Signal path optimization for read operations in storage devices

Techniques and memory devices are provided in which bit line short circuits are detected and groups of bit lines are masked off. A process tests groups of bit lines which are connected to a sense circuit. A masking latch is provided to store test results for each group of bit lines. Once the testing of a group is completed, the test result is communicated to a controller. Moreover, the same masking latch can store and communicate test results for multiple groups of bit lines which are connected to a sense circuit. In a user mode, a masking latch stores masking data for each group of bit lines. In response to a power on reset, the masking data is loaded into the masking latches and remains there over multiple write and read operation, until a next power on reset occurs.

Memory with bit line short circuit detection and masking of groups of bad bit lines

Apparatuses, systems, and methods are disclosed for controlling a data path for non-volatile memory. An apparatus includes one or more memory die. A memory die includes a memory core. A memory core includes an array of non-volatile memory cells and an internal data pipeline. A memory die includes a buffer that stores data associated with storage operations for a memory core. A memory die includes an internal controller that communicates with a memory core to initiate storage operations. An internal controller may delay initiating a storage operation in response to determining that an internal data pipeline and a buffer are both full.

Data path control for non-volatile memory

Apparatuses, systems, and methods are disclosed for an output data path for non-volatile memory. A buffer may include a plurality of buffer stages. A buffer stage width may be a width of an internal bus for a non-volatile memory element. A buffer may include two or more read pointers, updated by an internal controller at different times in response to different portions of a clock signal. A parallel-in serial-out (PISO) component may receive data via an internal data path having a data path width equal to an internal bus width, and may output the data in a series of transfers controlled according to a clock signal, via an output bus having an output bus width narrower than an internal bus width. A PISO component may receive data from a portion of a buffer stage in response to an internal controller updating a read pointer to point to the buffer stage.

Output data path for non-volatile memory

This disclosure provides a method and apparatus for detecting a transition of a memory cell current from a first state to a second state. An example apparatus includes a memory cell, a supplemental current source, a comparator, a reference voltage and a reference current source in a configuration that allows for real time detection of the transition of a memory cell. Detection of a memory cell current transition is captured when the output of the comparator transitions from one state to a second state in response to a sensing voltage exceeding the reference voltage.

Sensing amplifier to detect the memory cell current transition

Methods for precharging bit lines using closed-loop feedback are described. In one embodiment, a sense amplifier may include a bit line precharge circuit for setting a bit line to a read voltage prior to sensing a memory cell connected to the bit line. The bit line precharge circuit may include a first transistor in a source-follower configuration with a first gate and a first source node electrically coupled to the bit line. By applying local feedback from the first source node to the first gate, the bit line settling time may be reduced. In some cases, a first voltage applied to the first gate may be determined based on a first current drawn from the first bit line. Thus, the first voltage applied to the first gate may vary over time depending on the conductivity of a selected memory cell connected to the bit line.

Sense amplifier local feedback to control bit line voltage

A non-volatile memory is described that includes a sense amplifier that maintains a bit line voltage and output of the sense amplifier at a substantially constant voltage during read operations. During a preset phase, an output of the sense amplifier that is coupled to a selected bit line is grounded. At least one capacitor is precharged during the preset phase. During a sense phase, the sense amplifier output is disconnected from ground while the memory array is biased for reading a selected memory cell. A resulting cell current is integrated by the at least one capacitor. The integrated cell current discharges a sense node from the precharge level to an accurate voltage level based on the resulting cell current.

Sense amplifier with integrating capacitor and methods of operation

A method is provided for reading a memory cell of a nonvolatile memory system. The method includes generating a hard bit and N soft bits for the memory cell in a total time corresponding to a single read latency period and N+1 data transfer times.

Apparatus and methods for sensing hard bit and soft bits

A method is provided for operating a non-volatile storage system that includes a plurality of bit lines, a word line comb including a plurality of word lines, and a plurality of memory elements, each memory element coupled between one of the bit lines and one of the word lines. The method includes receiving a current conducted by the word line comb, estimating a resistance of a conductive path between the word line comb and a selected word line voltage node, and generating a voltage at the selected word line voltage node based on the received current and the estimated resistance so that a voltage of the word line comb substantially equals a reference voltage.

Word line compensation for memory arrays

A non-volatile memory includes a sense amplifier that uses a reference bit line. The sense amplifier includes a first capacitor coupled to a selected bit line and a second capacitor coupled to a reference bit line. The reference capacitor compensates for displacement currents in the selected bit line during sensing. Both plates of the capacitors are utilized to cancel leakage currents. The top plates of the capacitors are precharged then discharged during a sense phase. The selected bit line capacitor is discharged based on the selected cell current and the leakage current. The amount of discharge is transferred to the bottom plate of each capacitor, followed by discharging the bottom plates. The capacitor for the selected bit line is discharged based on the leakage current. In this manner, the correction phase facilitates a compensation based on the leakage current so that the selected cell current can be determined.

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Cupertino, CA, United States of America

Yingchang Chen