Analog-to-digital and digital-to-analog conversion window adjustment based on reference cells in a memory device

摘要

An analog-to-digital conversion window is defined by reference voltages stored in reference memory cells of a memory device. A first reference voltage is read to define an upper limit of the conversion window and a second reference voltage is read to define a lower limit of the conversion window. An analog voltage representing a digital bit pattern is read from a memory cell and converted to the digital bit pattern by an analog-to-digital conversion process using the conversion window as the limits for the sampling process. This scheme helps in real time tracking of the ADC window with changes in the program window of the memory array.

主权项

1. A memory device comprising:
a plurality of memory cells; a plurality of reference memory cells that are a subset of the plurality of memory cells, wherein a first group of at least two reference memory cells of the plurality of reference memory cells are used to define an upper limit, wherein a second group of at least two reference memory cells of the plurality of reference memory cells are used to define a lower limit, wherein the second group uses different reference memory cells than the first group; and an analog-to-digital conversion circuit coupled to the plurality of memory cells, wherein the analog-to-digital conversion circuit receives the upper limit and lower limit to define the conversion window.