Memory for storing the number of activations of a wordline, and memory systems including the same
A memory includes a first cell array configured to include a plurality of first memory cells connected to a plurality of word lines, a second cell array configured to include a plurality of second memory cells connected to the plurality of word lines, wherein a group of the plurality of second memory cells which are connected to a corresponding word line stores the number of activations for the corresponding word line, and an activation number update unit configured to update a value stored in the corresponding group of the plurality of second memory cells connected to the activated word line of the plurality of word lines.
1. A memory comprising:
a first cell array including a plurality of first memory cells connected to a plurality of word lines;
a second cell array including a plurality of second memory cells corresponding to the plurality of word lines, wherein the plurality of second memory cells store the number of activations for the corresponding word lines;
a signal generation unit configured to generate first and second signals for transferring data, in response to an active command for activating a word line; and
an update unit configured to receive a value stored in at least one of the second memory cells corresponding to an activated word line among the word lines, in response to the first signal, to increase the value, and to transfer the increased value to the at least one second memory cell corresponding to the activated word line, in response to the second signal,
wherein the signal generation unit comprises:
a first signal generation unit configured to delay the active command or the refresh command by a first time to generate the first signal; and
a second signal generation unit configured to delay the first signal by a second time to generate the second signal.
2. The memory system of claim 1 , wherein the update unit include:
an addition unit configured to increase the value input to an input terminal and output the increased value to an output terminal;
a first transfer unit configured to transfer the value from the at least one second memory cell corresponding to the activated word line to the input terminal of the addition unit, in response to the first signal; and
a second transfer unit configured to transfer the increased value from the output terminal of the addition unit to the at least one second memory cell corresponding to the activated word line, in response to the second signal.
3. The memory system of claim 2 , wherein the signal generation unit activates the first signal after the active command is applied, and activates the second signal after the first signal is activated and a predetermined time lapses.
4. The memory system of claim 1 , further comprising:
an alert signal generation unit configured to activate an alert signal when the value stored in the at least one second memory cell is equal to or greater than a given reference value.
5. The memory system of claim 1 , one or more adjacent word lines adjacent to a first word line are refreshed when the number of activations for the first word line is equal to or greater than a given reference value.