A method of refreshing several memory banks of a memory device that receives command signals from a memory controller. The processing elements transfer data to and from the memory at the memory address. Since the gain control device can separately perform dB-linear gain control, it is easily combined with a circuit, such as a continuous-time sigma-delta modulator, a continuous-time filter, and a continuous-time analog-to-digital converter, and enables miniaturization and low power consumption.