A control device and an associated method for driving a multi-function speaker supporting a plurality of predetermined functions including at least an audio function and a non-audio function includes a digital signal mixing block and a digital-to-analog block. The digital signal mixing block is arranged for receiving a plurality of digital input signals corresponding to the predetermined functions, respectively, and generating a digital mixed signal according to the digital input signals. The digital-to-analog block is coupled to the digital signal mixing block, for generating an analog driving signal to the multi-function speaker according to the digital mixed signal.