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Method and device for erasing nor type flash memory

A flash memory, over-erasure technology, applied in information storage, static memory, read-only memory, etc., can solve the problems of increasing time, insufficient erasing, and increasing the number of erasing operations.

Active Publication Date: 2021-05-07
GIGADEVICE SEMICON (BEIJING) INC +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

If the erasing operation time is too long, it means that the erasing is too deep, then the more times of over-erase verification in the process of over-erase verification, the longer the required programming operation time; if over-erase verification The number of times is less, for example, only 1 or 0 times, then the erasing operation time is too short, which means that the erasing is not enough, which will increase the number of erasing operations
Therefore, if the single erasing time set in advance is too long or too short, it will increase the time required for the entire erasing process.

Method used

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  • Method and device for erasing nor type flash memory
  • Method and device for erasing nor type flash memory
  • Method and device for erasing nor type flash memory

Examples

Experimental program
Comparison scheme
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Embodiment 1

[0034] figure 1 A schematic flow chart of a method for erasing a NOR flash memory provided by an embodiment of the present invention, the method can be performed by an erasing device for a NOR flash memory, wherein the device can be implemented by hardware and / or software, specifically including the following step:

[0035] Step 110, performing erasure verification on the storage unit.

[0036] In NOR flash memory, the time to erase a fixed-capacity storage unit is often one of the important performances of the memory, because the speed of erasing a fixed-capacity storage unit has a great impact on the operating speed of the memory. After the traditional erase operation, two verification operations are generally included: Over Erase Verify (OEV) and Erase Verify (EV). The main function of the over-erase verification operation is to avoid the problem that the threshold voltage of the erased memory cell is too low. For a memory cell that does not pass the overerasable verific...

Embodiment 2

[0045] figure 2 It is a schematic flowchart of a method for erasing a NOR flash memory provided by an embodiment of the present invention. On the basis of the above-mentioned embodiments, this embodiment specifically refines the judging process of over-erase verification and erasure verification, and determines the erase pulse signal according to the number of programming operations, and indicates an increase or decrease according to the erase pulse signal The specific steps for the preset erasing time of the erasing operation have been refined. Such as figure 2 As shown, the method specifically includes the following steps:

[0046] Step 210, performing erasure verification on the storage unit.

[0047] Step 220, read the threshold voltage of the memory cell, if the threshold voltage of the memory cell is less than the threshold voltage of the over-erased state, the memory cell has not passed the over-erased verification, perform a programming operation on the memory cel...

Embodiment 3

[0058] image 3 Shown is a schematic structural diagram of a device for erasing a NOR flash memory provided by Embodiment 3 of the present invention. The device can be implemented by hardware, such as image 3 As shown, the device includes:

[0059] The over-erasure verification module 310 is configured to perform erasure verification on the storage unit.

[0060] The programming module 320, the programming module 320 is connected with the over-erase verification module 310, and is used to perform at least one programming operation on the memory cells that have not passed the over-erasure verification.

[0061] The time controller 330, which is connected to the programming module 320, is used to record the number of programming operations, and determine the erase pulse signal according to the number of programming operations.

[0062] The erasure verification module 340 is connected to the over-erase verification module 310, and is used to perform erasure verification on mem...

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PUM

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Abstract

Embodiments of the present invention provide a method and device for erasing a NOR flash memory, including: performing erasure verification on storage cells; performing at least one programming operation on memory cells that have not passed the over erasure verification, and recording the The number of times of the programming operation; perform erasure verification on the memory cells that have performed at least one programming operation and passed the over-erase verification; determine the erasing pulse signal according to the number of times of the programming operation, and according to the erasing pulse signal , indicating to increase or decrease the preset erasing time for performing the erasing operation, and perform the erasing operation on the memory cells that fail the erasing verification. The embodiment of the present invention provides a method and device for erasing a NOR flash memory, which automatically adjusts the length of the erasing time by recording the number of times the memory unit is programmed after the current over-erasing verification fails, thereby reducing the erasing time , greatly improving the operating speed of NOR-type flash memory.

Description

technical field [0001] Embodiments of the present invention relate to the technical field of non-volatile memory, in particular to a method and device for erasing a NOR flash memory. Background technique [0002] In NOR flash memory, the time to erase a fixed-capacity storage unit is often used as one of the parameters to measure product performance. [0003] Traditional erasing methods include operations such as over-erase verification and erasure verification. The main function of the over-erase verification is to avoid the problem that the threshold voltage of the erased memory cell is too low. Because the threshold voltage that is too low will increase the time of the next programming operation. And erasure verification, its purpose is to see whether the memory cell is effectively erased. After the over-erased verification fails, a programming operation is required to increase the threshold voltage of the over-erased memory cell. However, after the erasure verificati...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G11C16/14G11C16/34
CPCG11C16/14G11C16/34
Inventor 张赛刘晓庆
Owner GIGADEVICE SEMICON (BEIJING) INC