Semiconductor device, refreshing method thereof, memory system, and electronic instrument
AssigneeSeiko Epson Corporation
InventorKoichi Mizugaki
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Abstract
The present invention provides a method of refreshing a semiconductor device such as a VSRAM. A memory cell array 20 of a semiconductor device 1 is divided into four blocks, specifically blocks A to D. During a period in which data read or write operations are being performed in one block, refreshing is performed for the remaining blocks. An ATD signal acts as a trigger for a series of operations during the reading or writing of memory cells. In a burst mode, refreshing is based on the ATD signal.
Claims8
A method of refreshing a semiconductor device having a memory cell array divided into a plurality of blocks, the method comprising:
- an external access step of reading or writing data continuously with respect to a block selected from the plurality of blocks, by generating a plurality of addresses continuously by a pulse signal, based on one address specified by an address signal;
- a detection signal generation step of generating a detection signal having a period longer than the pulse signal and detecting a change in the address signal;
- and
- a refreshing step of refreshing blocks in the plurality of blocks other than the selected block, based on the detection signal.
A semiconductor device comprising:
- a memory cell array divided into a plurality of blocks;
- a circuit which generates a pulse signal;
- a circuit which generates a detection signal having a period longer than the pulse signal and detecting a change in an address signal;
- an address generation circuit which generates a plurality of addresses sequentially by the pulse signal, based on the one address specified by the address signal, so as to perform continuous reading or writing of data with respect to a block selected from the plurality of blocks;
- and
- a refresh circuit which refreshes blocks in the plurality of blocks other than the selected block, based on the detection signal.
Dependencies are inferred from the claim text.