公开(公告)号：US09595320B2

公开(公告)日：2017-03-14

申请号：US14687686

申请日：2015-04-15

Applicant: Seagate Technology LLC

Inventor： Yingquan Wu ,  Earl T Cohen

IPC: G11C11/56 ,  G11C16/26 ,  G11C16/34

CPC classification number: G11C11/5642 ,  G11C16/26 ,  G11C16/3418 ,  G11C16/3454

Abstract: An SSD controller dynamically adjust read thresholds in a NVM to reduce errors due to device threshold voltage distribution shifts, thus improving performance, reliability, and/or cost of a storage sub-system, such as an SSD. In a first aspect, the controller periodically performs offline tracking on a portion of the NVM. The controller reads a representative sub-portion with current read thresholds. If the read meets a condition, then the controller reads the sub-portion with sample read thresholds, estimates the device threshold voltage distributions, and adjusts the current read thresholds of the portion to calculated new operating read thresholds of the sub-portion. In a second aspect, the portion includes data with a known statistical average number of zero and/or one bits.

Abstract translation: SSD控制器动态调整NVM中的读取阈值，以减少由于器件阈值电压分配偏移引起的错误，从而提高存储子系统（如SSD）的性能，可靠性和/或成本。 在第一方面，控制器周期性地对NVM的一部分进行离线跟踪。 控制器读取具有当前读取阈值的代表性子部分。 如果读取满足条件，则控制器读取具有采样读取阈值的子部分，估计器件阈值电压分布，并且调整部分的当前读取阈值以计算子部分的新的操作读取阈值。 在第二方面，该部分包括具有已知的统计平均数为零和/或一个比特的数据。