US Patent 7944759 Semiconductor memory device including floating body transistor

A semiconductor memory device includes a memory cell array including a plurality of memory cells having a transistor with a floating body, a source line driver configured to control the source lines to select the memory cells in response to an address signal, a source line voltage generation unit configured to generate a source line target voltage, receive an source line output voltage from the source line driver, compare the level of the source line output voltage with the level of the source line target voltage, generate a source line voltage of which the level is adaptively varied according to a temperature, and a sense amplifier configured to sense a difference in current flowing through the bit lines in response to data read from a selected memory cell, amplify the difference to a level having high output driving capability and output the amplified current.