An integrated circuit structure includes a static random access memory (SRAM) cell; a first power supply node connected to the SRAM cell, wherein the first power supply node is configured to provide a first positive power supply voltage to the SRAM cell; and a bit-line connected to the SRAM cell. A negative-voltage generator is coupled to, and configured to output a negative voltage to, the bit-line, wherein the negative-voltage generator is so configured that the negative voltage decreases in response to a decrease in the first positive power supply voltage and increases in response to an increase in the first positive supply voltage.