Display driving circuit and operating method for performing encoding and decoding
A display driver circuit receives externally-encoded image data and processes the data using a memory (graphic RAM), an internal encoder, and an external decoder configured to operate on the externally-encoded image data. The processed data is provided to a display device by a source driver of the display driver circuit. Data is processed through the graphic RAM and an internal decoder or the external decoder depending on whether a slice of the data is a currently received update slice, a recently received standby slice, or a still slice.
1. A method of operating a display driving circuit, the method comprising:
receiving an update slice;
writing the update slice to at least a portion of a graphic memory;
decoding the update slice to obtain first decoded data and image-processing the first decoded data to obtain image-processed data;
decoding at least one still slice among a plurality of slices stored in the graphic memory to obtain second decoded data; and
integrating the second decoded data and the image-processed data.
2. The method of claim 1 , wherein the at least one still slice corresponds to a slice that has not been updated during at least two frames.
3. The method of claim 1 , wherein the decoding of the update slice is different from the decoding of the at least one still slice, and the decoding of the update slice and the decoding of the at least one still slice are activated alternately.
4. The method of claim 1 , wherein the integrating of the second decoded data and the image-processed data further comprises rearranging the second decoded data and the image-processed data according to a slice order.
5. The method of claim 1 , wherein the update slice corresponds to a first slice including at least one pixel that is changed between a previous frame and a current frame.
6. A display driving circuit comprising:
a graphic memory configured to store a plurality of slices including an update slice and a still slice;
a first decoder configured to obtain first decoded data by decoding the update slice stored in the graphic memory;
a second decoder configured to obtain second decoded data by decoding the still slice stored in the graphic memory;
an image-processing pipeline configured to process the first decoded data to obtain image-processed data;
a source drive configured to integrate the image-processed data from the image-processing pipeline and the second decoded data to obtain integrated data.
7. The display driving circuit of claim 6 , further comprising:
an encoder configured to generate the still slice; and
a controller configured to receive the update slice, and write the update slice to at least a portion of the graphic memory.
8. The display driving circuit of claim 6 , wherein the still slice corresponds to a slice that has not been updated during at least two frames.
9. The display driving circuit of claim 7 , wherein the first decoder uses a first decoding method that is different from a second decoding method of the second decoder, and
wherein the controller is further configured to alternately activate the first decoder and the second decoder.
10. The display driving circuit of claim 7 , wherein the controller further comprises a slice type analysis circuit and a control signal generation circuit,
wherein the slice type analysis circuit is configured to:
identify a first slice updated in a current frame among slices of the graphic memory as the update slice, and
identify remaining slices excluding the update slice among the plurality of slices of the graphic memory as the still slice.
11. The display driving circuit of claim 6 , further comprising a source driver configured to output the integrated data to a display panel,
wherein the source driver is further configured to rearrange the second decoded data and the image-processed data according to a slice order by using a buffer to output the integrated data.
12. The display driving circuit of claim 10 , further comprising:
a first switching circuit configured to transmit a first output of one of the controller and a second encoder to the graphic memory;
a second switching circuit configured to transmit a second output from the graphic memory to one of the second decoder and the first decoder; and
a third switching circuit configured to transmit a third output of one of the second decoder and an image processing pipeline to a source driver.
13. The display driving circuit of claim 12 , wherein the control signal generation circuit is configured to:
generate a first mode signal in response to the update slice,
generate a second mode signal in response to the still slice.
14. The display driving circuit of claim 13 , wherein the first mode signal comprises first control signals for connecting a first input of the first switching circuit to the controller, connecting the second output of the second switching circuit to the first decoder, and connecting a third input of the third switching circuit to the image processing pipeline, and
the second mode signal comprises second control signals for connecting the second output of the second switching circuit to the second decoder, activating the second decoder, and connecting the third input of the third switching circuit to the second decoder.
15. A display driving circuit comprising:
a graphic memory configured to store a plurality of slices including an update slice and a still slice;
a decoder configured to obtain first decoded data from the update slice stored in the graphic memory, and a second decoded data from the still slice stored in the graphic memory;
an image-processing pipeline configured to process the first decoded data from the decoder to obtain image-processed data;
a source driver configured to integrate the second decoded data from the decoder and the image-processed data.
16. The display driving circuit of claim 15 , further comprising:
an encoder configured to generate the still slice; and
a controller configured to receive the update slice, and write the update slice to at least a portion of the graphic memory,
wherein the still slice corresponds to a slice that has not been updated during at least two frames.
17. The display driving circuit of claim 15 , wherein the source driver is further configured to:
rearrange the second decoded data and the image-processed data according to a slice order by using a buffer, and
output an integrated data to a display panel.
18. The display driving circuit of claim 16 , further comprising:
a first switching circuit configured to transmit, to the graphic memory, a first output which is from one of the controller and the encoder;
a second switching circuit configured to transmit, a second output of the decoder, to one of an image processing pipeline or a third switching circuit; and
the third switching circuit configured to transmit, to the source driver, a third output which is from one of the image processing pipeline or the second switching circuit.
19. The display driving circuit of claim 18 , wherein the decoder is configured to receive a first mode signal in response to the update slice, and receive a second mode signal in response to the still slice.
20. The display driving circuit of claim 19 , wherein the first mode signal comprises first control signals for connecting a first input of the first switching circuit to the controller, connecting a second input of the second switching circuit to the image processing pipeline, and for connecting a third input of the third switching circuit to the image processing pipeline,
wherein the second mode signal comprises second control signals for connecting the first input of the first switching circuit to the encoder, connecting the second input of the second switching circuit to the third switching circuit, and for connecting the third input of the third switching circuit to the second switching circuit.