An LCD device adapted to cut costs through the simplification of circuitry is disclosed. The LCD device includes a timing controller that includes: an inter-integrated circuit driver and a memory which are configured to communicate with an external system using an inter-integrated circuit protocol; and a logic element configured to operate a first logic signal from a first write protection terminal of the external system with a second logic signal from a second write protection terminal of the inter-integrated circuit driver, and to apply the operated logic signal to the memory. The memory replies to the operated logic signal from an output terminal of the logic element and performs a write operation.