Memory system with data line switching scheme
View Patent ↗A storage system includes a three-dimensional memory array that has multiple layers of non-volatile storage elements grouped into blocks. Each block includes a subset of first selection circuits for selectively coupling a subset of array lines (e.g. bit lines) of a first type to respective local data lines. Each block includes a subset of second selection circuits for selectively coupling a subset of the respective local data lines to global data lines that are connected to control circuitry. To increase the performance of memory operations, the second selection circuits can change their selections independently of each other.
1. A method for operating a data storage system of groups of non-volatile storage elements in which each group has its own set of first local data lines and its own set of second local data lines, comprising:
selectively connecting by first selection circuits the set of first local data lines for each group of the non-volatile storage elements to global data lines;
selectively connecting by second selection circuits each set of first local data lines to control lines in communication with a first subset of the non-volatile storage elements of the respective group;
concurrently beginning a memory operation on the first subsets of non-volatile storage elements in the groups;
independently detecting completion of the memory operation for each non-volatile storage element of the respective first subset; and
responsive to independently detecting completion of the memory operation on a respective non-volatile storage element of the respective first subset, independently selectively connecting a respective second local data line by a respective first selection circuit to a respective global data line and selectively connecting the respective second local data line by a respective second selection circuit to a control line of a second non-volatile storage element in a second subset of non-volatile storage elements of the respective group and commencing a memory operation on the second non-volatile storage element independently of any other memory operations being performed in respective group.
2. The method of claim 1 , further comprising:
responsive to detecting completion of the memory operation on an individual basis for each non-volatile storage element of the respective first subset, disconnecting a respective first local data line by respective first selection circuit from the respective global data line.
3. The method of claim 1 , wherein:
the groups of non-volatile storage elements includes sixteen groups of non-volatile storage elements;
each of the groups of non-volatile storage elements includes two reversible resistance-switching non-volatile storage elements;
the concurrently beginning a memory operation on the first subsets of non-volatile storage elements in the groups comprises changing a resistance of up to sixteen reversible resistance-switching non-volatile storage elements; and
the independently detecting completion of the memory operation for each non-volatile storage element of the respective first subset includes detecting change in resistance of the up to sixteen reversible resistance-switching non-volatile storage elements at different times.
4. The method of claim 1 , wherein the non-volatile storage elements are reversible resistance-switching non-volatile storage elements and the concurrently beginning a memory operation on the first subsets of non-volatile storage elements in the groups comprises:
applying a charge to a control line connected to a reversible resistance-switching non-volatile storage element for a first period of time that is insufficient to change the reversible resistance-switching non-volatile storage element from a first predetermined resistance state to a second predetermined resistance state; and
after the first period of time, allowing the control line to discharge the applied charge through the reversible resistance-switching non-volatile storage element in order to change the reversible resistance-switching non-volatile storage element from the first predetermined resistance state to the second predetermined resistance state, the detecting completion of the memory operation includes detecting the change from the first predetermined resistance state to the second predetermined resistance state.
5. The method of claim 1 , wherein:
the concurrently beginning a memory operation on the first subsets of non-volatile storage elements in the groups includes concurrently changing resistance of multiple reversible resistance-switching non-volatile storage elements in a monolithic three-dimensional memory array.
6. The method of claim 1 , wherein:
the first non-volatile storage element of each of the groups are all in a common block of non-volatile storage elements.
7. The method of claim 1 , wherein commencing a memory operation on the second non-volatile storage element independently of any other memory operations being performed in respective group further comprises:
commencing, for each group, the memory operation on the second non-volatile storage element of the group independently of the detection of completion of the memory operation for at least one first non-volatile storage element of at least one other group and in response to the independent detection of completion of the memory operation for the first non-volatile storage element of the group.
8. The method of claim 1 , wherein commencing a memory operation on the second non-volatile storage element independently of any other memory operations being performed in respective group further comprises:
commencing, for each group, the memory operation on the second non-volatile storage element of the group independently of the detection of completion of the memory operation for first non-volatile storage elements of the other groups and in response to the independent detection of completion of the memory operation for the first non-volatile storage element of the group.