A voltage generating circuit for semiconductor memory devices for use in avoiding the occurrence of leakage currents associated with parasitic diodes is presented. The circuit controls and stabilizes the generation of a fedback negative voltage to prevent parasitic diode malfunctions by a in a wordline driver. The voltage generating circuit includes a controller being fedback the negative voltage and detecting a potential difference between backbias voltage provided to a substrate of the cell and the negative voltage to generate a control signal. The voltage generating circuit also includes a voltage generator being fedback the negative voltage to detect a level thereof, and which subsequently generates and provides the negative voltage in response to the detected results of the negative voltage and the control signal.