A power management integrated circuit includes first pads, second pads, a third pad, and a fourth pad that are configured to be connected with an external device, a regulation block that receives first voltages from the first pads, converts the first voltages to second voltages, and outputs the second voltages to the second pads, a communication block that receives a command through the third pad and outputs an internal information request received together with the command responsive to the command, and a logic block that controls an operation of the regulation block, receives the internal information request from the communication block, and outputs internal state information to the fourth pad based on the internal information request.