Method for regulating the picture power in a television receiver

• US 6,768,520 B1
• Filed: 04/20/2000
• Issued: 07/27/2004
• Est. Priority Date: 10/20/1997
• Status: Expired due to Fees

• Current Assignee: Thomson Licensing SA (Vantiva SA)
• Original Assignee: Thomson Licensing SA (Vantiva SA)
• Inventors: Rilly, Gérard, Bicheler, Hans Guenter, Ahmari, Hossein, Kimmelmann, Stefan
• Primary Examiner(s): Lee, Michael H.
• Assistant Examiner(s): Tran, Trang U.
• Application Number:
  US09/529,922
• Time in Patent Office: 1,559 Days
• Field of Search: H04/N.563, H04/N.552, 348/678, 348/682, 348/380, 348/730, 348/687, 348/805, 348/797, 348/765, 348/766, 348/739, 345/60, 345/211, 345/212
• US Class Current: 348/730
• CPC Class Codes: H04N 5/57 Control of contrast or brightness

Abstract

In computer monitors having a picture tube, it may be seen that a small white picture area is displayed with the same white value as a large white picture area. If it were intended to achieve the same result for a television receiver with a picture tube, a voltage supply is necessary in which the power is permitted to fluctuate between 60 and 300 watts given a stable output voltage.

On account of the lower luminous efficiency, this effect would have considerably intensified repercussions on the power consumption of plasma screens.

The invention is based on the object of providing a simplified method for regulating the picture power in a television receiver.

The method according to the invention is distinguished by the following steps. The power consumption of the picture power is obtained by the video voltage R, G, B. The video voltage is converted into an information item which is then a measure of the picture power. This information item is subsequently fed to two regulating loops. In the fast loop, the value of the picture power in a short period of time is averaged. The fast loop, that is to say the fast regulation, ensures fast falling of the amplitude of the picture power for the case where a large number of lines are displayed completely white. This serves to ensure that the power consumption, which is defined beforehand, is not exceeded.

Claims

1. Method for regulating the picture power in a television receiver comprising the steps of:

forming a picture power representative signal from video signals coupled for display;

generating a control signal by comparing said picture power representative signal with a predetermined value;

displaying said video signals with a plasma display having power dissipation controlled in accordance with said control signal.

2. Method according to claim 1, wherein said forming step comprises the step of;

filtering said picture power representative signal with a tow pass.

3. Method according to claim 2, wherein said filtering step comprises the step of;

filtering with a short time constant and down regulating in accordance with said picture power representative signal having a maximum power and a short duration.

4. Method according to claim 2, wherein said filtering step comprises the step of;

filtering with a long time constant and down regulating in accordance with a thermal criteria.

5. Method according to claim 1, wherein said forming step comprises;

defining an area of white having a maximum luminance value in said video signals coupled for display and rapidly reducing said maximum luminance value for areas exceeding said area.

6. Method according to claim 1, wherein said controlling step comprises, reducing video signal amplitude rapidly during multiple line periods and increasing video signal amplitude during multiple field periods.

7. Method according to claim 1, wherein said generating step comprises;

setting said predetermined value in accordance with one of a manufacturing value and a user determined value.

8. Method according to claim 2, wherein said filtering step comprises the step of;

low pass filtering with filters of differing frequencies.

9. Method according to claim 1, wherein said displaying step comprises the step of;

controlling said video signals coupled for display in accordance with said control signal.

10. Method according to claim 2, wherein said filtering step comprises the step of;

filtering with a long time constant and down regulating in accordance with said picture power representative signal having a maximum power for a long duration.

11. A television receiver with power regulation comprising:

a video processor receiving video signals and controllably generating output video signals;

a plasma display coupled to display said controllably generated output video signals;

an interface responsive to a control signal for controlling power dissipation in said plasma display;

a converter circuit coupled to said controllably generated output video signals and generating therefrom a picture power representative signal, and;

a comparator circuit receiving said picture power representative signal and a reference signal for generating said control signal for said interface in accordance with said controllably generated output video signals.

12. Circuit according to claim 11, wherein said video processor has three output signals and these signals are converted into said picture power representative signal by the converter circuit.

13. Circuit according to claim 11, wherein a fast regulation loop cooperates with said interface for plasma regulation.

14. Circuit according to claim 11, wherein said comparator circuit is coupled to a control unit for filtering said picture power representative signal in accordance with a first and a second time constant.

15. Circuit according to claim 11, wherein said control signal is coupled to said video processor to control an amplitude of said output video signals.