Patent ID: 8031130

Claim:
A display driver comprising: a high-speed serial interface circuit that receives a packet from a host device through a high-speed serial bus using differential signals, and outputs a command or data included in the packet; a driver circuit that drives a main display panel based on the command or the data output from the high-speed serial interface circuit, the driver circuit having a driver section that generates a data line voltage and outputs the data line voltage to data lines of the main display panel; and a low-speed serial interface circuit that outputs a sub display driver command or a sub display driver data to a sub display driver through a low-speed serial bus when the packet received from the host device includes the sub display driver command or the sub display driver data, a transfer rate of the low-speed serial bus being lower than a transfer rata of the high-speed serial bus, the high-speed serial bus being a differential signal bus using the differential signals, and the amplitude of the differential signals of the high-speed serial bus being lower than the amplitude of a signal of the low-speed serial bus, the high-speed serial interface circuit being connected with the host device through the high-speed serial bus and being connected with the driver circuit, the driver circuit being connected with the main display panel and being connected with the low-speed serial interface circuit, the low-speed serial interface circuit being connected with the sub-display driver through the low-speed serial bus, when the packet received from the host device through the high-speed serial bus includes a main display driver command or a main display driver data, the main display driver command or the main display driver data being input to the driver circuit from the high-speed serial interface circuit, when the packet received from the host device through the high-speed serial bus includes the sub display driver command or the sub display driver data, the sub display driver command or the sub display driver data being input to the low-speed serial interlace circuit directly from the high-speed serial interface circuit or from the high-speed serial interface circuit through the driver circuit, and the low-speed serial interlace circuit outputting the sub display driver command or the sub display driver data to the sub display driver through the low-speed serial bus.