Non-volatile storage with reduced power consumption during read operations

Abstract

A non-volatile storage device in which power consumption is reduced by providing reduced read pass voltages on unselected word lines during a read operation. A programming status of one or more unselected word lines which are after a selected word line on which storage elements are being read is checked to determine whether the unselected word lines contain programmed storage elements. When an unprogrammed word line is identified, reduced read pass voltages are provided on that word line and other word lines which are after that word line in a programming order. The programming status can be determined by a flag stored in the word line, for instance, or by reading the word line at the lowest read state. The unselected word lines which are checked can be predetermined in a set of word lines, or determined adaptively based on a position of the selected word line.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application is related to co-pending, commonly assigned U.S. patent application Ser. No. ______, filed herewith, titled “Reducing Power Consumption During Read Operations In Non-Volatile Storage” (docket no. SAND-1228US0), incorporated herein by reference.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to non-volatile memory.[0004]2. Description of the Related Art[0005]Semiconductor memory has become increasingly popular for use in various electronic devices. For example, non-volatile semiconductor memory is used in cellular telephones, digital cameras, personal digital assistants, mobile computing devices, non-mobile computing devices and other devices. Electrically Erasable Programmable Read Only Memory (EEPROM) and flash memory are among the most popular non-volatile semiconductor memories. With flash memory, also a type of EEPROM, the contents of the whole memory array, or of a portio...

AI Technical Summary

Benefits of technology

[0012]The present invention addresses the above and other issues by providing non-volatile storage in which power consumption during a read operation is reduced. Power consumption is reduced in particular when many of the storage elements are in an erased, e.g., unprogrammed, state.

Problems solved by technology

However, one issue with memory devices is the need to reduce power consumption whenever possible, e.g., to reduce battery consumption and heat build up in portable electronic devices which use non-volatile memory.

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