A NAND flash read voltage calibration method, system and device

Abstract

The application discloses a NAND flash read voltage calibration method, system and device, and belongs to the technical field of flash memories. In order to solve the problems of the existing calibration, such as a large number of read times, large read disturbance, and inability to adapt to threshold voltage drift in real time, the method reads a first type page in a target storage block, detects and determines the independent voltage offset of each read threshold voltage; obtains the read disturbance cumulative count, the data retention time, the current working temperature and the erase-write cycle count; calculates the initial offset of each read threshold voltage of the third type page through a preset mapping function; takes the default read reference voltage superimposed with the initial offset as a scanning center, scans and collects the corresponding bit error rate in a narrow voltage interval; and determines the final offset based on the bit error rate and updates the read reference voltage. The application significantly reduces the calibration read times, reduces the read disturbance, and improves the calibration real-time performance and reliability.

Images