Device for driving a display panel with sequentially delayed drive signal
View Patent ↗A display device includes a scanning line drive circuit, which includes plural stages of D type of flip-flops (DFFs) connected in cascade. The first DFF stage receives a pixel signal of video data to be displayed. These DFF stages have outputs respectively connected to AND gates. The DFF stages and AND gates receive a common clock signal. The DFF stages are responsive to the clock signal to sequentially shift respective values held therein to the following stages with delay. Thus, a drive device is provided which can drive a display panel in a simple configuration without using an OE (Output Enable) signal.
1. A drive device for driving a display panel, said drive device including a scanning line drive circuit for driving said display panel in a direction of an array of scanning drive lines,
said scanning line drive circuit comprising:
a shift register having a plurality of delay circuits connected in cascade for delaying input data and sequentially shifting the input data in response to a positive-going edge of a first clock signal;
a plurality of operational circuits connected respectively to outputs of said plurality of delay circuits for operating the outputs of said plurality of delay circuits with the first clock signal;
a plurality of level shifters connected respectively to operational outputs of said plurality of operational circuits for shifting a voltage level of the respective operational outputs to output respective shifted levels; and
a generator circuit for generating the first clock signal and a second clock signal in accordance with a third clock signal, said shift register being operative in response to the first and second clock signals to shift the input data,
wherein said delay circuit holds the input data in response to the first clock signal, and outputs the input data in response to the second clock signal.
2. The drive device in accordance with claim 1 , wherein said generator circuit modifies a duty ratio of the third clock signal to generate the first clock signal.
3. The drive device in accordance with claim 2 , wherein said generator circuit inverts a phase of the first clock signal to generate the second clock signal.
4. The drive device in accordance with claim 1 , wherein said generator circuit inverts a phase of the third clock signal at timings different from each other and opposite in phase to generate the first and second clock signals.
5. The drive device in accordance with claim 1 , wherein said register performs a reset operation in response to a reset signal provided from outside.
6. The drive device in accordance with claim 1 , further comprising a signal line drive circuit for supplying a pixel signal to said display panel to drive said display panel.
7. The drive device in accordance with claim 1 , wherein said display panel is a liquid crystal display panel.