A source driver, a driving circuit using the same and a display apparatus using the same are provided. The display apparatus includes a display panel, a timing controller and a source driver. The timing controller is configured to receive an external image signal to provide a compressed image signal. The source driver is configured to receive the compressed image signal, and has a decompressor configured to convert the compressed image signal into restored image data and provide a plurality of source driving signals to drive the display panel according to a plurality of display data of the restored image data.