Circuit Configuration and Method for Controlling Particularly Segmented LED Background Illumination

• US 20100315442A1
• Filed: 07/10/2008
• Published: 12/16/2010
• Est. Priority Date: 07/18/2007
• Status: Active Grant

• Current Assignee: Dialog Semiconductors (UK) Limited
• Original Assignee: ams AG (Ams-Osram AG)
• Inventors: Pauritsch, Manfred
• Granted Patent: US 8,786,540 B2
• Time in Patent Office: Days
• US Class Current: 345/690
• CPC Class Codes: G09G 2310/024 Scrolling of light from the illumination source over the display in combination with the scanning of the display screen
• CPC Class Codes: G09G 2310/08 Details of timing specific for flat panels, other than clock recovery
• CPC Class Codes: G09G 2320/02 Improving the quality of display appearance
• CPC Class Codes: G09G 2320/0257 Reduction of after-image effects
• CPC Class Codes: G09G 2320/064 by time modulation of the brightness of the illumination source
• CPC Class Codes: G09G 3/342 using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers
• CPC Class Codes: H05B 45/46 having LEDs disposed in parallel lines

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

1. A circuit arrangement for controlling a segmented LED backlight for a display unit, having a generator with an input adapted to be supplied with a synchronizing signal that comprises line frequency information of the display unit, an additional input to be supplied with a data signal that comprises image information of the display, and with an output for providing a modulated signal for controlling the segmented LED backlight.

2. The circuit arrangement according to claim 1, wherein the synchronizing signal comprises image frequency information and line frequency information of the display unit.

3. The circuit arrangement according to claim 1, wherein the input adapted to be supplied with the synchronizing signal of the generator is coupled to a phase-locked loop.

4. The circuit arrangement according to claim 1, wherein the generator is configured so that the modulated signal is clocked to the synchronizing signal.

5. 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 synchronizing signal with the data signal.

6. The circuit arrangement according to claim 1, wherein the data signal comprises at least an image brightness information item of the display.

7. The circuit arrangement according to claim 1, wherein the data signal further comprises a respective image delay information item for an LED backlight, controlled segment by segment, of the display.

8. The circuit arrangement according to claim 1, wherein the generator comprises a pulse-width modulator.

9. The circuit arrangement according to claim 1, wherein the generator comprises a sigma-delta modulator.

10. 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.

11. A display driving unit according to claim 10, comprising:

another one of said circuit arrangement with an input to be supplied with the synchronizing signal 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 one of said driver with an input to be supplied with the additional modulated signal and an output that can adapted to be coupled to the additional connectable LED segment of the segmented LED backlight.

12. The display driving unit according to claim 11, wherein the synchronizing signal comprises image frequency information and line frequency information of the display unit.

13. A display unit with a display driving unit according to claim 11, 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 the outputs of the display driving unit.

14. A method for generating a modulated signal that comprises the steps of:

a) supplying a synchronizing signal that comprises line frequency information of a display unit;

b) supplying a data signal that has at least image brightness information of the display; and

c) providing a modulated signal by superimposing the synchronizing signal with the data signal.

15. The method according to claim 14, wherein the synchronizing signal comprises image frequency information and line frequency information of the display unit.

16. The method according to claim 14, wherein the synchronizing signal is supplied via a phase-locked loop.

17. The method according to claim 14, wherein the data signal further comprises image delay information for an LED backlight, controlled segment by segment, of the display.

18. The method according to claim 14, wherein the step of providing the modulated signal is performed by pulse-width modulation.

19. The method according to claim 14, wherein the step of providing the modulated signal is performed by sigma-delta modulation.

20. The method according to claim 14, wherein the modulated signal is supplied to at least the first segment of a segmented LED backlight.