# US 8,786,540 B2 · Circuit arrangement and method for driving segmented LED backlights in particular > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,786,540 B2 - Document ID: US8786540B2 - Status: Granted - Kind: B2 - Application number: 12/669,752 - Filed: 2008-07-10 - Published: 2010-12-16 - Granted: 2014-07-22 - Earliest claimed: 2007-07-18 - Assignees: Ams AG - Applicants: Manfred Pauritsch - Inventors: Manfred Pauritsch - Web page: https://patentgrep.com/patent/US8786540B2 ## CPC - G09G 3/342: {using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines} - H05B 45/46: having LEDs disposed in parallel lines - G09G 3/3611: {Control of matrices with row and column drivers} - G09G 2310/024: Scrolling of light from the illumination source over the display in combination with the scanning of the display screen - G09G 2310/08: Details of timing specific for flat panels, other than clock recovery - G09G 2320/02: Improving the quality of display appearance - G09G 2320/0257: Reduction of after-image effects - G09G 2320/064: by time modulation of the brightness of the illumination source - 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) - H05B: ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL ## Abstract A circuit arrangement for controlling a segmented LED backlight in particular, comprises a generator (50) with a first input (10) to be supplied with a synchronizing signal (SYNC) that comprises image frequency information and/or line frequency information of a display unit, a second input (20) to be supplied with a data signal (DATA) that comprises image information of the display unit, and with an output (30) for providing a modulated signal (MOD). ## Claims ### Claim 1 A circuit arrangement for controlling a segmented LED backlight for a display unit, having a generator with at least one input adapted to be supplied with one or more synchronizing signals comprising line frequency information and image frequency information of the display unit, an additional input to be supplied with a data signal that comprises an image delay information item and an image brightness information item of a respective segment of the segmented LED backlight, and with an output for providing a modulated signal for controlling the segmented LED backlight, wherein the generator is configured to provide the modulated signal as a function of the data signal such that the image frequency information is delayed by the image delay information item, a leading edge of the modulated signal is synchronized with the line frequency information and a pulse of the delayed image frequency information, and a trailing edge of the modulated signal is synchronized with the line frequency information and a pulse of the image frequency information. ### Claim 2 (depends on 1) The circuit arrangement according to claim 1, wherein one or more of the at least one input adapted to be supplied with the one or more synchronizing signals of the generator is coupled to a phase-locked loop. ### Claim 3 (depends on 1) The circuit arrangement according to claim 1, wherein the generator is configured so that the modulated signal is clocked to the one or more synchronizing signals. ### Claim 4 (depends on 1) The circuit arrangement according to claim 1, wherein the generator is configured to provide the modulated signal as a function of a modulation of the one or more synchronizing signals with the data signal. ### Claim 5 (depends on 1) The circuit arrangement according to claim 1, wherein the generator comprises a pulse-width modulator. ### Claim 6 (depends on 1) The circuit arrangement according to claim 1, wherein the generator comprises a sigma-delta modulator. ### Claim 7 (depends on 1) A display driving unit with a circuit arrangement according to claim 1, comprising a driver with an input that is coupled to the output of the generator, and to an output adapted to be connected to an LED segment of the segmented LED backlight in particular. ### Claim 8 (depends on 7) A display driving unit according to claim 7, comprising: another one of said circuit arrangement, with an input to be supplied with a one of the one or more synchronizing signals that comprises line frequency information of the display unit, an additional input to be supplied with an additional data signal that comprises image information for an additional connectable LED segment, and with an output for providing an additional modulated signal; and an additional driver with an input to be supplied with the additional modulated signal and an output adapted to be coupled to the additional connectable LED segment of the segmented LED backlight. ### Claim 9 (depends on 8) The display driving unit according to claim 8, wherein the one of the one or more synchronizing signals comprises image frequency information and line frequency information of the display unit. ### Claim 10 (depends on 8) A display unit with a display driving unit according to claim 8, comprising: a digital video processor with outputs for providing the synchronizing signal and for providing at least a first and a second data signal for driving a first and a second LED segment, wherein the outputs of the digital video processor are coupled to associated inputs of the display driving unit; and at least a first and a second LED segment of the segmented LED backlight, each connected to outputs of the display driving unit. ### Claim 11 A method for generating a modulated signal for controlling a segmented LED backlight for a display unit, the method comprising: supplying a synchronizing signal that comprises line frequency information and image frequency information of the display unit; supplying a data signal that has at least an image delay information item and an image brightness information item of a respective segment of the segmented LED backlight; and providing a modulated signal for controlling the segmented LED backlight such that the image frequency information is delayed by the image delay information item, a leading edge of the modulated signal is synchronized with the line frequency information and a pulse of the delayed image frequency information, and a trailing edge of the modulated signal is synchronized with the line frequency information and a pulse of the image frequency information. ### Claim 12 (depends on 11) The method according to claim 11, wherein the synchronizing signal is supplied via a phase-locked loop. ### Claim 13 (depends on 11) The method according to claim 11, wherein the providing the modulated signal is performed by pulse-width modulation. ### Claim 14 (depends on 11) The method according to claim 11, wherein the providing the modulated signal is performed by sigma-delta modulation. ### Claim 15 (depends on 11) The method according to claim 11, wherein the modulated signal is supplied to at least a first segment of a plurality of segments of the segmented LED backlight. ### Claim 16 A circuit arrangement for controlling a segmented LED backlight for a display unit, having a generator with at least one input adapted to be supplied with one or more synchronizing signals comprising line frequency information and image frequency information of the display unit, an additional input to be supplied with a data signal that comprises an image delay information item and an image brightness information item of a respective segment of the segmented LED backlight, and with an output for providing a modulated signal for controlling the segmented LED backlight, wherein the generator is configured to provide a delayed signal such that the image frequency information is delayed by the image delay information item and the delayed image frequency information is synchronized with the line frequency information, and wherein the generator is further configured to provide the modulated signal by combining the delayed image frequency information with the image brightness information item in a pulse-width modulation such that a leading edge of the modulated signal is synchronized with a pulse of the delayed image frequency information and a trailing edge of the modulated signal is synchronized with a pulse of the image frequency information. ### Claim 17 A method for generating a modulated signal for controlling a segmented LED backlight for a display unit, the method comprising: supplying a synchronizing signal that comprises line frequency information and image frequency information of the display unit; supplying a data signal that has at least an image delay information item and an image brightness information item of a respective segment of the segmented LED backlight; providing a delayed signal such that the image frequency information is delayed by the image delay information item and the delayed image frequency information is synchronized with the line frequency information; and providing a modulated signal for controlling the segmented LED backlight by combining the delayed image frequency information with the image brightness information item in a pulse-width modulation such that a leading edge of the modulated signal is synchronized with a pulse of the delayed image frequency information and a trailing edge of the modulated signal is synchronized with the image frequency information. ### Claim 18 (depends on 1) The circuit arrangement according to claim 1, wherein the generator is configured to provide the modulated signal by combining the delayed image frequency information with the image brightness information item in a pulse-width modulation. ### Claim 19 A circuit arrangement for controlling a segmented LED backlight for a display unit, the circuit arrangement comprising: a generator comprising: at least one input adapted to be supplied with one or more synchronizing signals comprising line frequency information and image frequency information of the display unit; an additional input adapted to be supplied with a data signal comprising an image delay information item and an image brightness information item of a respective segment of the segmented LED backlight; and an output for providing a modulated signal for controlling the segmented LED backlight; wherein the generator is configured to: delay the image frequency information based on the image delay information item, generate a leading edge of a pulse of the modulated signal to allow the leading edge to be synchronized with the line frequency information and allow the leading edge to be synchronized with a pulse of the delayed image frequency information, and generate a trailing edge of the pulse of the modulated signal to allow the trailing edge to be synchronized with the line frequency information and to allow the trailing edge to be synchronized with a pulse of the image frequency information. ### Claim 20 (depends on 19) The circuit arrangement according to claim 19, wherein the generator is further configured to: generate a leading edge of a subsequent pulse of the modulated signal to allow the leading edge of the subsequent pulse to be synchronized with the line frequency information and to allow the leading edge of the subsequent pulse to be initiated prior to an additional pulse of the delayed image frequency information.