Multistage memory cell read

摘要

A multistage read can dynamically change wordline capacitance as a function of threshold voltage of a memory cell being read. The multistage read can reduce current spikes and reduce the heating up of a memory cell during a read. A memory device includes a global wordline driver to connect a wordline of a selected memory cell to the sensing circuit, and a local wordline driver local to the memory cell. After the wordline is charged to a read voltage, control logic can selectively enable and disable a portion or all of the global wordline driver and the local wordline driver in conjunction with applying different discrete voltage levels to the bitline to perform a multistage read.

主权项

1. A method comprising:
charging a wordline of a memory device having a memory cell selected to read; enabling a global wordline driver that connects a global wordline path from the wordline to a sensing circuit that reads the memory cell, and enabling a local wordline driver that connects a local wordline path to the global wordline path; disabling the global wordline driver and maintaining enabled the local wordline driver; applying an initial voltage to a bitline of the selected memory cell; disabling the local wordline driver and maintaining disabled the global wordline driver; applying a higher voltage to the bitline; and enabling the global wordline driver and the local wordline driver to connect the memory cell to the sensing circuit to read the selected memory cell.