Patent ID: 8699803
Filing Date: 2014-04-15
Classification: G09G,H04N

Abstract:
1. A display driving circuit comprising: an overdrive calculation circuit operable to generate an overdrive activation signal for improving a response characteristic of an external display drive according to display image data; a drive-output device operable to supply the overdrive activation signal to the display device; a compression circuit operable to store compressed display data created by compressing the display image data in a memory, wherein the compression circuit includes a DCT calculation module operable to execute a discrete cosine transform of the display image data, and an entropy coding module operable to execute a variable length entropy coding of DCT conversion display data arising through an output of the DCT calculation module; a decompression circuit operable to supply the overdrive calculation circuit with decompressed display data created by decompressing the compressed display data read out from the memory, wherein the decompression circuit includes an inverse-entropy-coding circuit operable to execute an inverse entropy coding, which is an inverse of the variable length entropy coding by the entropy coding module, and an inverse DCT conversion module operable to execute an inverse DCT conversion which is an inverse of the discrete cosine transform by the DCT calculation module; an other decompression circuit to which the DCT conversion display data created by the DCT calculation module of the compression circuit can be supplied without passing through the memory, wherein the other decompression circuit includes an other inverse DCT conversion module operable to execute an other inverse DCT conversion, which is an inverse of the discrete cosine transform by the DCT calculation module, other decompressed display data arising from an output of the other decompression circuit are supplied to the overdrive calculation circuit, wherein the other decompressed display data arising from the output of the other decompression circuit in connection with display image data of a current frame are supplied to the overdrive calculation circuit, the decompressed display data arising from the decompression circuit in connection with display image data of a preceding frame read out from the memory are supplied to the overdrive calculation circuit, wherein the compression circuit includes first and second quantization modules connected with an output of the DCT calculation module, an output signal arising from an output of the first quantization module is supplied to the other decompression circuit without passing through the memory, an output signal arising from an output of the second quantization module is supplied to an input of the entropy coding module, the other decompression circuit includes a first inverse quantization module having an output connected with an input of the other inverse DCT conversion module, and having an input to which the output signal generated by the first quantization module of the compression circuit is supplied, and the decompression circuit includes a second inverse quantization module having an input connected with an output of the inverse-entropy-coding circuit, and having an output connected with an input of the inverse DCT conversion module.