Refresh method capable of reducing memory cell access time in semiconductor memory device

A refresh method for a semiconductor memory device comprising the steps of:

• latching a low address for refresh operation when the refresh operation is requested;
• determining a mode of the semiconductor memory device;
• activating a word line for the refresh operation by decoding the latched low address for the refresh operation when the mode of the semiconductor memory device is a stand-by mode;
• and
• simultaneously performing the refresh operation of the latched low address and a normal operation in different memory cell blocks when the mode of the semiconductor memory device is a busy mode and a normal operation mode is inputted.

A refresh method for a semiconductor memory device comprising the steps of:

• latching a low address for refresh operation when the refresh operation is requested;
• determining a mode of the semiconductor memory device;
• comparing block selection bits of a low address for normal operation with block selection bits of the latched low address for the refresh operation when a normal operation command is inputted in a busy mode of the semiconductor memory device;
• performing the refresh operation of the latched low address while performing the normal operation when the block selection bits of the low address for the normal operation are different from the block selection bits of the latched low address for the refresh operation.