# US 10,872,555 B2 · Display drive circuit > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,872,555 B2 - Document ID: US10872555B2 - Status: Granted - Kind: B2 - Application number: 14/918,499 - Filed: 2015-10-20 - Published: 2016-04-28 - Granted: 2020-12-22 - Earliest claimed: 2014-10-27 - Assignees: Synaptics Japan GK - Applicants: Synaptics Japan GK - Inventors: Atsushi Shikata - Web page: https://patentgrep.com/patent/US10872555B2 ## CPC - G09G 3/2096: {Details of the interface to the display terminal specific for a flat panel (suitable for both CRT and flat panel G09G5/006; specific for a CRT G09G1/167)} - G09G 2310/08: Details of timing specific for flat panels, other than clock recovery - G09G 2320/0247: Flicker reduction other than flicker reduction circuits used for single beam cathode-ray tubes - G09G 2320/0626: for control of overall brightness - G09G 2320/064: by time modulation of the brightness of the illumination source - G09G 2320/0646: Modulation of illumination source brightness and image signal correlated to each other - G09G 2330/022: in absence of operation, e.g. no data being entered during a predetermined time - G09G: ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION (arrangements for transferring data between digital computers and displays G06F3/14; static indicating arrangements comprising an association of a number of separate sources or light control cells G09F9/00; static indicating arrangements comprising integral associations of a number of light sources H01J, H01K, H10H, H05B33/12; scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission, details thereof H04N1/00) ## Abstract A circuit apparatus is provided for driving source electrodes of a display panel based on image data and to control a backlight of the display panel. For example, the circuit apparatus includes a display drive (DD) circuit having a parameter generation (PG) part and an image data conversion (IDC) part. The PG part is operable to generate an image data-conversion parameter and a backlight control parameter based on a brightness distribution of the image data of one frame. The IDC part is operable to convert the image data based on the image data-conversion parameter. The DD circuit is operable to output source signals generated based on the converted image data and output, control the backlight based on the backlight control parameter, and stop an action of the parameter generation part in response to no change in the image data of one frame from image data of a preceding frame being detected. ## Claims ### Claim 1 A display driver comprising: an interface operable to receive, from an external host processor, an image data write command and image data; a memory configured to store a frame of the image data responsive to the image data write command; parameter generation circuitry operable to generate an image data-conversion parameter and a backlight control parameter based on a brightness distribution of the frame of the image data; backlight control circuitry operable to control a backlight of a display based on the backlight control parameter; image data conversion circuitry operable to convert the image data based on the image data-conversion parameter; source driver circuitry operable to drive source electrodes of the display with source signals that are based on the converted image data; detection circuitry operable to: detect whether the image data write command is received; and generate, responsive to detecting an absence of the image data write command, a detection signal with a first value indicating that there is no change between the frame and a preceding frame of the image data; and clock control circuitry configured to: stop supplying a first clock signal to the parameter generation circuitry during a first period in response to the first value of the detection signal; and supply a second clock signal to the backlight control circuitry during the first period, wherein the parameter generation circuitry is configured to stop generating at least one of the image data-conversion parameter and the backlight control parameter responsive to the clock control circuitry stopping the supply of the first clock signal. ### Claim 2 (depends on 1) The display driver according to claim 1, wherein the detection circuitry is further operable to: responsive to detecting a presence of the image data write command, generate the detection signal with a second value that configures the parameter generation circuitry to resume generating at least one of the image data-conversion parameter and the backlight control parameter. ### Claim 3 (depends on 2) The display driver according to claim 2, wherein detecting the absence of the image data write command comprises detecting an absence of the image data write command for a predefined period of one frame or longer. ### Claim 4 (depends on 3) The display driver according to claim 3, wherein the interface is compliant with MIPI-DSI standards. ### Claim 5 (depends on 2) The display driver according to claim 2, further comprising: a register configured to store an adjustment parameter to supply to the parameter generation circuitry, wherein the detection circuitry is further configured to: detect whether a write of the adjustment parameter to the register has occurred; generate, responsive to determining that the write of the adjustment parameter has not occurred during a predefined period of one frame or longer, the detection signal with the first value; and responsive to detecting the write of the adjustment parameter, generate the detection signal with the second value that configures the parameter generation circuitry to resume generating at least one of the image data-conversion parameter and the backlight control parameter. ### Claim 6 (depends on 5) The display driver according to claim 5, wherein the parameter generation circuitry is further configured to: during a dimming period, gradually change the image data-conversion parameter and the backlight control parameter in response to a change in at least one of the brightness distribution and the adjustment parameter, wherein the predefined period occurs after the dimming period has ended. ### Claim 7 (depends on 1) The display driver according to claim 1, wherein at least the parameter generation circuitry, the image data conversion circuitry, and the memory are formed on a common semiconductor substrate. ### Claim 8 (depends on 1) The display driver according to claim 1, wherein the detection circuitry is supplied with the received image data, wherein the parameter generation circuitry comprises: data extraction circuitry configured to: receive the image data received through the interface; and extract the brightness distribution of the frame of the image data; and analysis/calculation circuitry operable to generate the image data-conversion parameter and the backlight control parameter based on the extracted brightness distribution, wherein the detection circuitry is further operable to detect whether the image data of the frame matches that of the preceding frame, and wherein the analysis/calculation circuitry is configured to generate at least one of the image data-conversion parameter and the backlight control parameter. ### Claim 9 (depends on 8) The display driver according to claim 8, wherein detecting whether the image data of the frame matches that of the preceding frame comprises: applying a predetermined function to the image data of the frame to produce a first result; applying the predetermined function to the image data of the preceding frame to produce a second result; and comparing the first result and the second result. ### Claim 10 (depends on 9) The display driver according to claim 9, wherein the predetermined function is a cyclic redundancy check. ### Claim 11 (depends on 8) The display driver according to claim 8, further comprising: a register configured to store an adjustment parameter to be supplied to the parameter generation circuitry, wherein the detection circuitry is further configured to: detect whether a write of the adjustment parameter to the register has occurred; and generate, responsive to determining that the write of the adjustment parameter has not occurred during a predefined period of one frame or longer, the detection signal with the first value. ### Claim 12 (depends on 11) The display driver according to claim 11, wherein the parameter generation circuitry is further configured to: during a dimming period, gradually change the image data-conversion parameter and the backlight control parameter in response to a change in at least one of the brightness distribution and the adjustment parameter, wherein the predefined period occurs after the dimming period has ended. ### Claim 13 (depends on 8) The display driver according to claim 8, wherein the clock control circuitry is further configured to: stop supplying a third clock signal to the analysis/calculation circuitry in response to the detection signal. ### Claim 14 (depends on 8) The display driver according to claim 8, wherein at least the parameter generation circuitry and the image data conversion circuitry are formed on a common semiconductor substrate. ### Claim 15 An apparatus comprising: an interface operable to receive, from an external host processor, an image data write command and image data; a memory configured to store a frame of the image data responsive to the image data write command; parameter generation circuitry operable to generate an image data-conversion parameter based on a brightness distribution of the frame of the image data; image data conversion circuitry operable to convert the image data based on the image data-conversion parameter; source driver circuitry operable to drive source electrodes of a display with source signals that are based on the converted image data; detection circuitry operable to: detect whether the image data write command is received; and generate, responsive to detecting an absence of the image data write command, a detection signal with a first value indicating that there is no change between the frame and a preceding frame of the image data; and clock control circuitry configured to: stop supplying a first clock signal to the parameter generation circuitry during a first period in response to the first value of the detection signal; and supply a second clock signal to backlight control circuitry during the first period, wherein the parameter generation circuitry is configured to stop generating the image data-conversion parameter responsive to the clock control circuitry stopping the supply of the first clock signal. ### Claim 16 (depends on 15) The apparatus according to claim 15, further comprising: a register configured to store an adjustment parameter to supply to the parameter generation circuitry, wherein the detection circuitry is further configured to: detect whether a write of the adjustment parameter to the register has occurred; generate, responsive to determining that the write of the adjustment parameter has not occurred during a predefined period of one frame or longer, the detection signal with the first value; and generate, responsive to detecting one of the write of the adjustment parameter to the register and a presence of the image data write command, the detection signal with a second value that configures the parameter generation circuitry to resume generating the image data-conversion parameter. ### Claim 17 (depends on 15) The apparatus according to claim 15, further comprising: a register configured to store an adjustment parameter to supply to the parameter generation circuitry, wherein the parameter generation circuitry comprises: data extraction circuitry configured to: receive the image data through the interface; and extract the brightness distribution of the frame of the image data; and analysis/calculation circuitry operable to generate the image data-conversion parameter based on the extracted brightness distribution, and wherein the detection circuitry is further configured to determine whether the image data of the frame matches image data of the preceding frame. ### Claim 18 (depends on 5) The display driver of claim 5, wherein detecting whether the write of the adjustment parameter to the register has occurred comprises detecting one of: a write command for the register, and a write enable signal for the register. ### Claim 19 A method of operating a display driver, the method comprising: receiving, from an external host processor, image data comprising a first frame; responsive to an image data write command from the external host processor, storing the first frame in a memory of the display driver; generating a conversion parameter based on a brightness distribution of the first frame; converting the image data based on the conversion parameter; driving source electrodes of a display with source signals based on the converted image data; responsive to determining that the image data write command is not received within a predefined period of one frame or longer, generating a detection signal with a first value indicating that there is no change between the first frame and a subsequent second frame of the image data; responsive to the first value of the detection signal, stopping supplying a first clock signal to parameter generation circuitry during a first period; supplying, during the first period, a second clock signal to a blacklight control circuitry; and responsive to stopping supplying the first clock signal, transmitting a control signal to thereby stop generating the conversion parameter.