A semiconductor memory device may include a power control signal generator and a sense amplifier circuit. The power control signal generator may generate a first power control signal, the first power control signal having an enablement period that may be controlled in response to a temperature signal having a cycle time. The cycle time may be controlled according to a mode signal and an internal temperature. The sense amplifier circuit may generate a first power signal driven to have a first drive voltage in response to the first power control signal. In addition, the sense amplifier circuit may sense and amplify a level of a bit line using the first power signal as a power supply voltage.