Semiconductor integrated circuit device for driving liquid crystal display
View Patent ↗The present invention realizes a semiconductor integrated circuit device for driving liquid crystal (liquid crystal control driver IC) capable of easily setting drive conditions and the like according to specifications of a liquid crystal display to be used. An electrically-programmable nonvolatile memory circuit (EPROM) or an electrically erasable and programmable nonvolatile memory circuit (EEPROM) is provided in a semiconductor integrated circuit device for driving a liquid crystal display, and setting information is stored in the memory circuit. The memory circuit is constructed by a normal device which can be formed in the same process as a semiconductor manufacturing process of forming devices of other circuits.
1. A semiconductor integrated circuit device for generating and outputting a drive signal applied to a scan line of a display panel to be driven and a drive signal applied to a signal line of the display panel, the semiconductor integrated circuit device comprising:
a nonvolatile memory circuit; and
a power supply circuit to generate a writing voltage to write data in the nonvolatile memory circuit and an erasing voltage to erase data in the nonvolatile memory circuit,
wherein the nonvolatile memory circuit has an element formed by a semiconductor manufacturing process of forming an element of another circuit on a same semiconductor chip as the semiconductor integrated circuit device,
wherein the nonvolatile memory circuit comprises an electrically erasable programmable area to store setting information adapted to characteristics of the display panel,
wherein the nonvolatile memory circuit is comprised of multiple memory cells, each of the multiple memory cells being isolated by an isolation area, and
wherein each of said multiple memory cells includes:
a first field effect transistor for writing data in a first well formed in a main surface of a semiconductor substrate;
a second field effect transistor for reading data in the first well formed in the main surface of the semiconductor substrate; and
a third field effect transistor that functions as a capacitive element in a second well formed in the main surface of the semiconductor substrate and arranged to be isolated from the first well,
wherein floating gates of the first field effect transistor, the second field effect transistor, and the third field effect transistor are coupled together, and
wherein a writing operation is performed when a common positive voltage is applied to a source and a drain of the third field effect transistor.
2. A semiconductor integrated circuit device according to claim 1 , wherein each of the nonvolatile memory circuit and said another circuit is a CMOS circuit including a P-channel-type field effect transistor and an N-channel-type field effect transistor.