A control device and a memory system are provided. The control device includes a first peripheral circuit group and a second peripheral circuit group. The first peripheral circuit group and a memory array are driven by a first voltage in a standby mode. The first peripheral circuit group provides a control command when recognizing that a command string is a deep power-down (DPD) execution command string. When receiving the control command, the second peripheral circuit group provides a DPD signal having a first logic value to stop providing the first voltage so that the memory system enters a DPD mode. In the DPD mode, when recognizing that the command string is a DPD exit command string, the second peripheral circuit group provides a DPD signal having a second logic value to provide the first voltage so that the memory system enters standby mode.