Sandisk Technologies Inc.

Sandisk Corporation

Farookh Moogat

Yan Li

Dana Lee

Raul-Adrian Cernea

Chris Avila

Gautam Ashok Dusija

Grishma Shah

Venkatesh Ramachandra

Tai-Yuan Tseng

Alexander K Mak

Yi-Chieh Chen

Jianmin Huang

Teruhiko Kamei

Toru Miwa

Changyuan Chen

Deepak Raghu

Cynthia Hsu

Fanglin Zhang

Yishai Kagan

Shouchang Tsao

Rizwan Ahmed

Masaaki Higashitani

Deepanshu Dutta

Chang Hua Siau

Alon Marcu

Aaron Keith Olbrich

Ali K Al-Shamma

Kwang-Ho Kim

Yacov Duzly

Khanh Vinh Nguyen

YenLung Li

Steven S Cheng

Alexander Kwok-Tung Mak

Kenneth Louie

Jong Hak Yuh

Alexander Chu

Dennis S Ea

Shou-Chang Tsao

Kapil Verma

Sense circuits in a memory device can be pre-charged to different levels in a sensing process to reduce the amount of time used for sensing. During sensing of first and second memory cells, a control circuit pre-charges first and second sense circuits to first and second voltages, respectively. The first and second sense circuits are associated with the first and second memory cells, respectively. Also, during the sensing, a control gate voltage is applied to the first and second memory cells. The control circuit allows the first and second sense node voltages to discharge in a common discharge period and the cells are sensed using a common trip condition. The first and second memory cells are therefore subject to different concurrent verify tests.

Memory device which performs verify operations using different sense node pre-charge voltages and a common discharge period

Systems and methods for reducing peak power supply current in a non-volatile memory system that includes a plurality of memory die are described. In some cases, prior to a first memory die of the plurality of memory die performing a particular memory operation (e.g., a programming operation), the first memory die may poll other memory die of the plurality of memory die to determine a total peak power supply current for the plurality of memory die. In response to detecting that the total peak power supply current for the plurality of memory die is at or above a peak current threshold (e.g., more than 200 mA), the first memory die may delay the performance of the particular memory operation or slow down the performance of the particular memory operation.

Ad hoc digital multi-die polling for peak ICC management

Methods for reducing pin capacitance and improving off-chip driver performance by using TSVs to enable usage of off-chip drivers located within selected and unselected die of a plurality of stacked die are described. A reduction in pin capacitance allows for faster switching times and/or lower power operation. In some embodiments, a TSV may connect an internal node (e.g., the output of a pre-driver) within a selected die of a plurality of stacked die with the input of an off-chip driver within an unselected die of the plurality of stacked die. In some cases, only a single die within a die stack may be selected (or enabled) at a given time. Using a TSV to connect internal nodes associated with off-chip drivers located within both selected and unselected die of the die stack allows for reduced off-chip driver sizing and thus reduced pin capacitance.

I/O pin capacitance reduction using TSVs

A non-volatile memory with multiple memory dice manages simultaneous operations so as to not exceed a system power capacity. A load signal bus is pulled up with a strength proportional to the system power capacity. Each die has a driver to pull down the bus by an amount corresponding to its degree of power need as estimated by a state machine of the die. The bus therefore provides a load signal that serves as arbitration between the system power capacity and the cumulative loads of the individual dice. The load signal is therefore at a high state when the system power capacity is not exceeded; otherwise it is at a low state. When a die wishes to perform an operation and requests a certain amount of power, it drives the bus accordingly and its state machine either proceeds with the operation or not, depending on the load signal.

Non-volatile memory and method with peak current control

I/O pin capacitance reduction using TSVS

In a nonvolatile memory, hybrid blocks are initially written with only lower page data. The hybrid blocks later have middle and upper page data written. For high speed writes, data is written to a hybrid block and two or more Single Level Cell (SLC) blocks. The data from the SLC blocks are copied to the hybrid block at a later time in a folding operation.

In-situ block folding for nonvolatile memory

A programming operation for a set of non-volatile storage elements determines whether the storage elements have been programmed properly after a program-verify test is passed and a program status=pass is issued. Write data is reconstructed from sets of latches associated with the storage elements using logical operations optionally one or more reconstruction read operations. Normal read operations are also performed to obtain read data. A number of mismatches between the read data and the reconstructed write data is determined, and determination is made as to whether re-writing of the write data is required based on the number of the mismatches.

Defect or program disturb detection with full data recovery capability

A NAND flash memory chip has a configurable interface that can communicate with a NAND flash memory controller using either parallel communication or serial communication. Serial communication requires fewer channels. Control information from the NAND flash memory controller uses a small number of channels. Double Data Rate (DDR) communication provides serial communication with adequate data transfer speed.

NAND flash memory interface

Techniques, related to a flash memory device having a non-volatile memory array (NVM), for recovering from a write interrupt resulting from host-supplied memory voltage fault are disclosed. A memory controller is configured to control a response to an occurrence of the write-interrupt, the response including writing to the NVM, after the memory voltage is verified as being within an acceptable range, one or more of a safe copy of a portion of a first sector of upper-page data and a safe copy of a portion of a second sector of lower-page data, and terminating the write interrupt. Terminating the write-interrupt may include receiving new data from the host while avoiding sending an error message to the host.

Flash memory techniques for recovering from write interrupt resulting from voltage fault

A method and system for phasing power-intensive operations is disclosed. A non-volatile storage device controller detects a power reset. The controller is in communication with non-volatile memories in the non-volatile storage device. In response to detecting a power reset, the controller determines a current consumption necessary to reset the non-volatile memories in the non-volatile storage device. The controller simultaneously resets all of the non-volatile memories when the determined current consumption is less than a current consumption threshold. If the determined current consumption is greater than the current consumption threshold, the controller resets a first subset of the plurality of non-volatile memories, and after a predetermined delay, resets a second subset of the non-volatile memories. Therefore, a power-intensive operation may be performed without exceeding a current consumption threshold by dividing the operation into a sequence of steps that do not exceed the threshold.

Phased NAND power-on reset

A mechanism is presented memory circuits, such a NAND-type flash memories, to autonomously protect themselves from temporary and short power drops. A detection mechanism looks for the supply voltage to drop below a function voltage for a period of time. When such an event occurs, a suspend mechanism is activated, and after completing the last micro-operation (such as a program pulse) the memory freezes. When power is again stable at an operational level, the suspended operation is resumed. The memory controller can then be notified upon occurrence of such voltage drop by polling a special status bit. Examples of how the pausing can be implemented include altering of clock signals and suspending sub-phases of larger operations.

Immunity against temporary and short power drops in non-volatile memory

A memory has defective locations in its user portion replaceable by redundant locations in a redundant portion. Data latches in the user and redundant portions allow data sensed from or to be written to a memory to be exchanged with a data bus. A defective location latching redundancy scheme assumes the column circuits including data latches for defective columns to be still useable. The data latches for the defective columns are used to buffer corresponding redundant data that are normally accessible from their data latches in the redundant portion. In this way both the user and redundant data are available from the user data latches, and streaming data into or out of the data bus is simplified and performance improved.

Method for column redundancy using data latches in solid-state memories

A NAND type flash memory is organized into NAND strings with each being a chain of memory cells in series and connected via select transistors on both ends of the string to either a bit line or a source line. The memory cells adjacent both ends of a NAND string are particularly susceptible to errors due to program disturb. An adaptive memory-state partitioning scheme is employed to overcome the errors, in which each memory cells are generally partitioned to store multiple bits of data, except for the ones adjacent both ends where relatively less bits are stored. In this way, the storage of relatively less bits in the memory cells adjacent both ends of a NAND string affords sufficient margin to overcome the errors. For example, in a memory designed to store 2-bit data, the cells adjacent both ends of a NAND string would each be configured to store one bit of the 2-bit data.

Method of NAND flash memory cell array with adaptive memory state partitioning

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Fremont, CA, United States of America

Farookh Moogat