Semiconductor display device and method of driving the same

A semiconductor display device comprising:

• a source signal line drive circuit unit constituted by plural thin-film transistors;
• a gate signal line drive circuit unit constituted by plural thin-film transistors;
• and
• a pixel unit in which plural pixel thin-film transistors are arranged like a matrix;
• wherein,
• the gate signal line drive circuit unit has at least one tristate buffer and one gate selection pulse change-over switch per a gate signal line;
• the tristate buffer has:
• a first circuit that includes a pair of n-channel thin-film transistor and p-channel thin-film transistor;
• and
• a second circuit that includes a pair of n-channel thin-film transistor and p-channel thin-film transistor;
• the source region of the n-channel thin-film transistor in the first circuit is electrically connected, at a first connection point, to the source region of the p-channel thin-film transistor of the second circuit;
• a first power source is electrically connected to the source region of the p-channel thin-film transistor of the first circuit;
• a second power source having a potential lower than that of the first power source is electrically connected to the first connection point;
• a third power source having a potential lower than the second power source is electrically connected to the source region of the n-channel thin-film transistor of the second circuit;
• and
• an output signal line of the first circuit and an output signal line of the second circuit are both electrically connected to the gate signal line at a second connection point.