Sandisk Technologies Inc.

Sandisk Corporation

Sandisk Il Ltd.

Yee Lih Koh

Man Lung Mui

Eran Sharon

Idan Alrod

Gerrit Jan Hemink

Toru Miwa

Tien-Chien Kuo

Sergey Anatolievich Gorobets

Jun Wan

Seungpil Lee

Hao Nguyen

Changyuan Chen

Mrinal Kochar

Cynthia Hsu

Chris Nga Yee Avila

YenLung Li

Jongmin Park

Alexander Kwok-Tung Mak

Jonathan Hsu

Juan Lee

Tosha Pandya

Vamsi Krishna Sakhamuri

Techniques are provided for efficiently performing programming operations in a memory device. In particular, power consumption is reduced in sensing circuitry by avoiding pre-charging of bit lines for certain memory cells at certain times during a programming operation. One approach uses knowledge of the different phases of a programming operation to reduce the number of unnecessary bit line pre-charges. For example, during the lower program loop numbers of a programming operation, bit line pre-charging may occur for lower data states but not for higher data states. Similarly, during the higher program loop numbers, bit line pre-charging may occur for higher data states but not for lower data states. In another approach, which may or may not incorporate knowledge of the different phases of a programming operation, the setting of the bit line pre-charge can be updated at least once after it is initially set in the verify portion.

Adaptive selective bit line pre-charge for current savings and fast programming

When writing a multi-state non-volatile memory, a de-trapping operation is included in the programming cycle. To reduce the performance penalty of including a de-trapping operation, the programming cycle of a single series of increasing pulses alternating with verify operations is replaced with a cycle including a pulse from each of two or more staircases, where each staircase is for a corresponding subset of the data states. After the multiple pulses, but before the following verify, a de-trapping operation is inserted in the programming cycle.

Multi-pulse programming cycle of non-volatile memory for enhanced de-trapping

A system and methods for programming non-volatile memory elements by using latches to transfer data. Upon discovering errors in previously programmed non-volatile memory elements, the system recovers the corresponding data from the latches and programming the recovered data to other non-volatile memory elements.

Preserving data from adjacent word lines while programming binary non-volatile storage elements

A memory device cooperating with a memory controller scrambles each unit of data using a selected scrambling key before storing it in an array of nonvolatile memory cells. This helps to reduce program disturbs, user read disturbs, and floating gate to floating gate coupling that result from repeated and long term storage of specific data patterns. For a given page of data having a logical address and for storing at a physical address, the key is selected from a finite sequence thereof as a function of both the logical address and the physical address. In a block management scheme the memory array is organized into erase blocks, the physical address is the relative page number in each block. When logical address are grouped into logical groups and manipulated as a group and each group is storable into a sub-block, the physical address is the relative page number in the sub-block.

Non-volatile memory and method with improved data scrambling

In a programming operation that includes repeated bitscan, program, and verify steps, the bitscan steps may be hidden by performing bitscan in parallel with program preparation and program steps. The effect of a program step may be predicted from previous observation so that when a bitscan indicates that the memory cells are close to being programmed, a last programming step may be completed without subsequent verification or bitscan steps.

Memory system with unverified program step

A non-volatile memory has its cells' thresholds programmed within any one of a first set of voltage bands partitioned by a first set of reference thresholds across a threshold window. The cells are read at a higher resolution relative to a second set of reference thresholds so as to provide additional soft bits for error correction. The reference thresholds of the second set are set up to be non-uniformly distributed on the threshold window so as to provide higher resolution at designated regions. At the same time they are conducive to be read in groups for soft bits to be read bit-by-bit systematically with a simple algorithm and read circuit and using a minimum of data latches. This is accomplished by relaxing the requirement that the first set of reference threshold is a subset of the second set and that the resulting soft bits are symmetrically distributed about the hard bits.

Non-volatile memory and methods with asymmetric soft read points around hard read points

Non-volatile memory and methods with reading soft bits in non uniform schemes

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Milpitas, CA, United States of America

Yee Lih Koh