Sharp Kabushiki Kaisha Corporation

Shunsuke Hayashi

Hajime Washio

Seijirou Gyouten

Sachio Tsujino

Eiji Matsuda

Yuhichiroh Murakami

Yuichiro Murakami

Mamoru Onda

Keiichi Ina

Nobuhiko Suzuki

Hiroshi Murofushi

A level shift circuit includes first and second level shifters which respectively output first and second output signals that are produced by level shifting two kinds of input clock signals whose high level periods do not overlap. The level shift circuit also includes control transistors and control lines which, together, prevent a feedthrough current from flowing into the second level shifter when the first output signal is high level, and prevent a feedthrough current from flowing into the first level shifter when the second output signal is high level, so as to suspend the level shift operation of the first and second level shifters. With the level shift circuit, power consumption during a specific time period in a non-active period of the clock signal can be eliminated, where the specific time period of one clock signal is the active period of the other clock signal.

Level shifter circuit and display device provided therewith

A shift register includes plural stages of flip-flops. The last-stage flip-flop Fn and the flip-flop Fn&#x2212;1 that is the preceding flip-flop thereof are reset by inputting thereto an output signal from the last-stage flip-flop. A delaying means is provided, between an output terminal Q of the last-stage flip-flop for outputting the output signal and an input terminal R of the last-stage flip-flop for receiving the output signal, for delaying an input of the output signal to the input terminal R. The flip-flop Fn is reset at same time or after the preceding flip-flop Fn&#x2212;1 is reset. With this arrangement, it is possible to prevent malfunctions of circuits due to a failure to reset the flip-flops.

Shift register and display device using same

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.

Scanning direction control circuit and display device

A driver circuit for a display device includes a plurality of set-reset flip-flops and switch circuits, and is arranged so that a timing pulse for sampling outputted from the flip-flop is supplied to the switch circuit, so as to cause the switch circuit to receive a clock signal. The clock signal operates as a set signal of the next stage flip-flop and outputted as a control signal for carrying out pre-charging of a data signal line and a selected pixel connected to the data signal line, with a switch. Thus, in case of performing pre-charging of a signal supplying line with an internal pre-charging circuit by using a pre-charging power source having small driving ability, this arrangement can provide a driver circuit for a display device capable of preventing fluctuation of a signal supplied to a different signal supplying line, while keeping the circuit scale of the shift register small.

Driver circuit and shift register of display device and display device

The present invention includes: a shift register section, including multiple-stage flip-flops operating in synchronism with a clock signal, for switching a shift direction in accordance with an externally supplied direction instruct signal; a waveform change section for changing in waveform a signal output of one of the flip-flops which is in a first predetermined stage; and an inspection signal switching section for switching, in accordance with the direction instruct signal, an output between the signal output which has been changed in waveform in the waveform change section and a signal output of one of the flip-flops which is in a second predetermined stage.

Growing community of inventors

Onomichi, Japan

Shunsuke Hayashi