Memory system
AssigneeKioxia Corporation
InventorsTakehiko Amaki, Yoshihisa Kojima, Toshikatsu Hida, Marie Grace Izabelle Angeles Sia, Riki Suzuki, Shohei Asami
Life of this patent
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Abstract
According to one embodiment, a memory system includes a semiconductor memory and a controller. The semiconductor memory includes blocks each containing memory cells. The controller is configured to instruct the semiconductor memory to execute a first operation and a second operation. In the first operation and the second operation, the semiconductor memory selects at least one of the blocks, and applies at least one voltage to all memory cells contained in said selected blocks. A number of blocks to which said voltage is applied per unit time in the second operation is larger than that in the first operation.
Claims20
A method of controlling a nonvolatile memory, the nonvolatile memory including a plurality of blocks, each of the plurality of blocks including a plurality of word lines, said method comprising:
- instructing the nonvolatile memory to execute a dummy read operation on a first group of blocks within a first period;
- and
- changing, on the basis of a remaining time of the first period, a rate indicating the number of blocks to be selected per unit time, wherein
- in the dummy read operation, at least one block of the first group of blocks is selected, and a voltage higher than a ground voltage is applied to each word line of the plurality of word lines included in the selected block.
A method of controlling a semiconductor memory in a memory system, the semiconductor memory including a plurality of blocks, each of the plurality of blocks including a plurality of word lines and a plurality of memory cells, each of the plurality of word lines connecting at least one of the plurality of memory cells, said method comprising:
- instructing the semiconductor memory to perform a first operation after power begins to be supplied to the memory system before data is read out from a first block among the plurality of blocks;
- and
- instructing the semiconductor memory to perform the first operation again within a first period after instructing the semiconductor memory to perform the first operation, wherein
- in the first operation, the semiconductor memory applies a voltage to a first word line of the first block and does not output, to outside of the semiconductor memory, data stored in a memory cell connected to the first word line.
A method of controlling a nonvolatile memory, the nonvolatile memory including a plurality of blocks, each of the plurality of blocks including a plurality of word lines, said method comprising:
- determining a first period;
- and
- instructing the nonvolatile memory to execute a dummy read operation on a first group of blocks within the first period, wherein
- in the dummy read operation, at least one block of the first group of blocks is selected, and a voltage higher than a ground voltage is applied to each word line of the plurality of word lines included in the selected block, and
- the dummy read operation includes a first dummy read operation and a second dummy read operation, and the number of blocks selected in one execution of the first dummy read operation is smaller than the number of blocks selected in one execution of the second dummy read operation.
Dependencies are inferred from the claim text.