A control circuit is provided. A memory is configured to store a program code. A central processing unit (CPU) executes a plurality of instructions according to the program code. When a specific instruction is executed by the CPU, the CPU generates a control signal. A power mode management circuit generates a selection signal according to the control signal. A processing circuit transforms first power data according to the selection signal. A first storage circuit stores the first power data. The processing circuit generates first set data and second set data according to first power data. A first specific device operates in a first power mode according to the first set data. A second specific device operates in a second power mode according to the second set data. The first storage circuit, the power mode management circuit and the processing circuit are in an always-on state.