Patent ID: 9367389
Filing Date: 2016-06-14
CPC Classification: G06F,G11C,H03M

Claim Text:
1. A method for applying a sequence of sensing/read reference voltages in a read channel, comprising the steps of: setting a respective read window for each respective threshold voltage of a set of threshold voltages defining different states of a memory cell storing multiple bits based on an estimate of the read channel, wherein each respective read window for each respective threshold voltage is set to encompass an intersection of two threshold voltage distribution tails associated with each respective threshold voltage; setting a first value, a second value, and a third value of the sequence of read reference voltages for a first hard read, a second hard read and a third hard read of each respective read window, wherein the first value corresponds to a point central to the respective read window, and the second and third values correspond to different ones of a left-hand limit of the respective read window and a right-hand limit of the respective read window; determining whether the first, the second and the third hard reads of each respective read window are successful; and if the first, the second and the third hard reads are not successful, setting a fourth value and a fifth value of the sequence of read reference voltages for a fourth hard read and a fifth hard read of each respective read window, the fourth value and the fifth value corresponding to different ones of (i) a point between the left-hand limit of the respective read window and the point central to the respective read window and (ii) a point between the right-hand limit of the respective read window and the point central to the respective read window.