DISPLAY DRIVER, OPERATING METHOD THEREOF, HOST FOR CONTROLLING THE DISPLAY DRIVER, AND SYSTEM HAVING THE DISPLAY DRIVER AND THE HOST

• US 20130057763A1
• Filed: 08/31/2012
• Published: 03/07/2013
• Est. Priority Date: 09/02/2011
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Hyo Jin Kim, Hyun-Chul Lee, Jong Seon Kim, Sang Kyu Lee
• Inventors: KIM, Jong Seon, CHA, Chi Ho, LEE, Sang Kyu, LEE, Hyun-Chul, KIM, Hyo Jin, LEE, Hak-Seong, IN, Seung Jin, CHOI, Hyon Jun
• Granted Patent: US 8,878,995 B2
• Time in Patent Office: Days
• US Class Current: 348/554
• CPC Class Codes: G06F 1/3265 Power saving in display device
• CPC Class Codes: G09G 2320/103 Detection of image changes, e.g. determination of an index representative of the image change
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 2330/12 Test circuits or failure detection circuits included in a display system, as permanent part thereof
• CPC Class Codes: G09G 2360/10 Display system comprising arrangements, such as a coprocessor, specific for motion video images
• CPC Class Codes: G09G 2360/18 Use of a frame buffer in a display terminal, inclusive of the display panel
• CPC Class Codes: G09G 2370/04 Exchange of auxiliary data, i.e. other than image data, between monitor and graphics controller
• CPC Class Codes: G09G 2370/10 Use of a protocol of communication by packets in interfaces along the display data pipeline
• CPC Class Codes: G09G 5/006 Details of the interface to the display terminal specific for a display terminal using a CRT G09G1/167; using a flat panel G09G3/2096; circuits for interfacing with colour displays G09G5/04
• CPC Class Codes: G09G 5/12 Synchronisation between the display unit and other units, e.g. other display units, video-disc players
• CPC Class Codes: G09G 5/18 Timing circuits for raster scan displays specially adapted for television H04N ; synchronisation between the display unit and other display units, videodisc player G09G5/12
• CPC Class Codes: G09G 5/36 characterised by the display of a graphic pattern, e.g. using an all-points-addressable [APA] memory

Abstract

An operation method of a display driver includes generating a count value by counting a period of a synchronization signal related to a synchronization packet received from a host, receiving a mode change command from the host, the mode change command indicating a change from a video mode transmitting first image data to a display by bypassing a frame memory to a command mode transmitting second image data to the display through the frame memory, and generating an internal synchronization signal having a period substantially equal to the period of the synchronization signal by using the count value based on the mode change command after a last pulse of the synchronization signal is generated. A time interval between the last pulse and a first pulse of the internal synchronization signal is equal to the period of the synchronization signal.

Claims

1-18. -18. (canceled)

19. A display driver comprising:

a receiver configured to receive an image signal including a mode change command indicating whether the image signal to be displayed on a display is a still image signal or a moving image signal;

a control circuit configured to generate first control signals and second control signals in response to the mode change command transmitted from the receiver;

a first interface configured to output the still image signal from the receiver using a memory in response to the first control signals; and

a second interface configured to output the moving image signal from the receiver without using the memory in response to the second control signals.

20. The display driver of claim 19, wherein the first interface comprises:

a first switching circuit configured to control transmission of the still image signal in response to the first control signals; and

a selection circuit configured to transmit the still image signal received from the first switching circuit or the moving image signal received from the second interface to the memory in response to a selection signal generated by the control circuit based on the mode change command.

21. The display driver of claim 20, wherein the second interface comprises a second switching circuit configured to output the moving image signal transmitted from the receiver to at least one of the selection circuit and an output port of the second interface in response to the second control signals.

22. The display driver of claim 21, wherein the second switching circuit is configured to simultaneously output the moving image signal transmitted from the receiver to the selection circuit and the output port of the second interface for a desired period of time in response to the second control signals.

23. The display driver of claim 19, wherein the first interface is an interface supporting mobile industry processor interface (MIPI®

) command mode or a central processing unit (CPU) interface, and the second interface is an interface supporting MIPI®

video mode or an RGB interface.

24. The display driver of claim 19, wherein the mode change command is embedded in a vertical blanking interval included in the still image signal or the moving image signal.

25. The display driver of claim 19, further comprising:

a first selection circuit configured to output the still image signal output from the memory or the moving image signal output from the second interface in response to a first selection signal; and

an output circuit configured to transmit an image signal output from the first selection circuit to the display, the control circuit configured to generate the first selection signal in response to the mode change command.

26. The display driver of claim 25, wherein

the first interface includes a first switching circuit configured to transmit the still image signal to the memory in response to the first control signals and a scan switching circuit configured to transmit the still image signal from the memory to the first selection circuit in response to a scan switching signal;

the second interface includes a second switching circuit configured to transmit the moving image signal to the first selection circuit in response to the second control signals.

27. The display driver of claim 25, wherein

the first interface includes a first switching circuit configured to transmit the still image signal in response to the first control signals, a second selection circuit configured to output the still image signal received from the first switching circuit or the moving image signal received from the second interface to the memory in response to a second selection signal, a scan switching circuit configured to transmit the still image signal from the memory to the first selection circuit in response to a scan switching signal, and

the second interface includes a second switching circuit configured to transmit the moving image signal to at least one of the first selection circuit and the second selection circuit in response to the second control signals, the control circuit configured to generate the second selection signal and the scan switching signal in response to the mode change command.

28. The display driver of claim 27, wherein the scan switching circuit is in an on state in response to the scan switching signal while the second switching circuit transmits the moving image signal to the second selection circuit in response to the second control signals, and the scan switching circuit is in an off state in response to the scan switching signal while the second switching circuit transmits the moving image signal to the first selection circuit in response to the second control signals.

29. The display driver of claim 27, wherein if the second switching circuit transmits the moving image signal to both of the first and second selection circuits simultaneously in response to the second control signals, the scan switching circuit is turned off in response to the scan switching signal.

30. A portable communication device comprising:

a display;

a display driver configured to transmit an image signal to the display; and

a host configured to transmit the image signal including a mode change command, which indicates whether the image signal to be displayed on the display is a still image signal or a moving image signal, to the display driver, the display driver including,

a control circuit configured to generate first control signals and second control signals in response to the mode change command;

a first interface configured to transmit the still image signal to the display using a memory in response to the first control signals; and

a second interface configured to transmit the moving image signal to the display without using the memory in response to the second control signals.

31. The communication device of claim 30, wherein the display driver further comprises:

a first selection circuit configured to output the image signal output from an output port of the first interface or an output port of the second interface in response to a first selection signal; and

an output circuit configured to transmit the image signal output from the first selection circuit to the display, the first interface including,

a first switching circuit configured to transmit the still image signal in response to the first control signals;

a second selection circuit configured to output the still image signal received from the first switching circuit or the moving image signal received from the second interface to the memory in response to a second selection signal; and

a scan switching circuit configured to transmit the still image signal from the memory to the first selection circuit in response to a scan switching signal, the second interface including,

a second switching circuit configured to transmit the moving image signal to at least one circuit among the first selection circuit and the second selection circuit in response to the second control signals, the control circuit configured to generate the first selection signal, the second selection signal, and the scan switching signal in response to the mode change command.

32. The communication device of claim 31, wherein if the moving image signal is transmitted following the still image signal or if the still image signal is transmitted following the moving image signal, the output circuit is disabled for a period corresponding to at least one frame according to the control of a timing controller.

33. The communication device of claim 30, wherein the host is configured to determine whether the image signal is the still image signal or the moving image signal based on operation or non-operation of a codec and generate the mode change command according to a determination result.

34. The communication device of claim 33, wherein the host is configured to monitor a tearing effect control signal received from the display driver and transmit the mode change command to the display driver in a vertical blanking interval according to a monitoring result.

35. The communication device of claim 30, wherein the host is configured to transmit the mode change command, which indicates that the moving image signal is transmitted following the still image signal, to the display driver in a vertical blanking interval and then immediately transmit the moving image signal to the display driver.

36. The communication device of claim 35, wherein the vertical blanking interval is a vertical front porch.

37. The communication device of claim 30, wherein the host is configured to transmit the mode change command, which indicates that the still image signal is transmitted following the moving image signal, to the display driver in a vertical blanking interval and then transmit a first still image frame of the still image signal to the display driver before a first falling edge of a tearing effect control signal.

38. The communication device of claim 37, wherein the vertical blanking interval is a vertical back porch.

39. The communication device of claim 30, wherein the second interface is configured to transmit the moving image signal to both of the display and the memory, simultaneously, in response to the second control signals, and the first interface is configured to transmit the moving image signal from the memory to the display driver in response to a switching signal output from the control circuit.

40. An operation method of a display driver, the method comprising:

generating control signals in response to a mode change command, which indicates whether an image signal to be displayed on a display is a still image signal or a moving image signal; and

switching between a command mode, in which the still image signal is transmitted to the display via a memory, and a video mode, in which the moving image signal is transmitted to the display without using the memory, in response to the control signals.

41. The method of claim 40, wherein the mode change command is embedded in a vertical blanking interval of the still image signal or the moving image signal.

42. The method of claim 40, further comprising:

not transmitting the image signal to the display during at least one frame of the image signal if switching is performed between the video mode and the command mode.

43-53. -53. (canceled)