Patent attributes
The subject invention discloses a scanning direction control circuit, which includes a bidirectional shift register in which shifting direction is switched in accordance with a switching signal L/R, which is step-upped by a level shifter when having lower amplitude than the driving voltage. The scanning direction control circuit includes a latch circuit between the level shifter and the bidirectional shift register, and a control circuit causes the latch circuit to carry out latching operation after shifting operation of flip-flops constituting the bidirectional shift register is completed in response to output signals of the flip-flops. The control circuit brings the level shifter into active state in a period before, at and after the latching timing, and brings the level shifter into inactive state in the remaining period. With this arrangement, the switching signal L/R can be supplied at a predetermined timing regardless of external input timing thereof, with low power consumption.
