Backlight drive voltage control device, backlight drive voltage control method and television

Patent metadata

Field	Value
Publication number	US-10147364-B2
Application number	US-201213664797-A
Country	US
Kind code	B2
Filing date	Oct 31, 2012
Priority date	Apr 20, 2012
Publication date	Dec 4, 2018
Grant date	Dec 4, 2018

Abstract

A backlight drive voltage control device, comprising: a detecting unit connected to a controller, which detects the current states of the lamp strings of the divisions of the backlight sources of a liquid crystal screen, sends feedback signals to the controller; the controller which sends a voltage adjustment control signal to an AC to DC converter according to the feedback signals, and acquires the voltage adjustment amount of each lamp string according to the voltage adjustment control signal, selects lamp strings which voltage adjustment amounts are larger than the threshold, and sends the closing feedback control signal to the detecting unit; and the AC to DC converter which outputs corresponding voltages to the lamp strings according to the voltage adjustment control signal.

First claim

The invention claimed is:

1. A backlight drive circuit, comprising:
lamp strings;
a detecting circuit, connected between a controller and the lamp strings, and configured to detect current states of lamp strings in each division of backlight sources of a liquid crystal screen, and send feedback signals to the controller according to the current states;
the controller, configured to calculate a voltage adjustment amount for each lamp string according to the feedback signals, wherein the voltage adjustment amount is a difference between an output voltage of an AC to DC converter resulting from the feedback signal of a lamp string and an output voltage of the AC to DC converter corresponding to the current state of the lamp string leading to the feedback signal; and the controller is further configured to control the detecting circuit to stop generating feedback signals from lamp strings having voltage adjustment amounts above a threshold, and control the AC to DC converter to output voltages according to remaining feedback signals;
the AC to DC converter, configured to generate a drive voltage for the lamp strings according to the remaining feedback signals, so that all the lamp strings work at a rated current.

2. The drive circuit according to claim 1 , wherein the detecting circuit comprises at least a constant current control chip and an acquisition circuit, and the acquisition circuit is located between the constant current control chip and the controller.

3. The drive circuit according to claim 2 , wherein a controlled current source or a diode is arranged between the acquisition circuit and the constant current control chip.

4. The drive circuit according to claim 1 , wherein the controller comprises at least one of a field programmable gate array and a signal chip microcomputer.

5. A backlight drive voltage control method, comprising:
detecting current states of lamp strings in each division of backlight sources of a liquid crystal screen;
generating feedback signals according to the current states;
calculating a voltage adjustment amount for each lamp string according to the feedback signals, wherein the voltage adjustment amount is a difference between an output voltage of an AC to DC converter resulting from the feedback signal of a lamp string and an output voltage of the AC to DC converter corresponding to the current state of the lamp string leading to the feedback signal;
stopping generating feedback signals from lamp strings having voltage adjustment amounts above a threshold, and adjusting voltages output by the AC to DC converter according to remaining feedback signals;
outputting, by the AC to DC converter, adjusted voltages to drive the lamp strings, so that all the lamp strings work at a rated current.

6. The method according to claim 5 , wherein stopping generating feedback signals from lamp stings having voltage adjustment amounts above the threshold comprises:
storing addresses of lamp strings having voltage adjustment amounts above the threshold;
reading the stored addresses for lamp strings having voltage adjustment amounts above the threshold; and
stopping generating feedback signals from lamp strings associated with the stored addresses.

7. A backlight drive voltage control method, comprising:
detecting, by a detecting circuit, current states of lamp strings in each division of backlight sources of a liquid crystal screen, and generating feedback signals according to the current states;
receiving, by a controller, the feedback signals, and calculating a voltage adjustment amount for each lamp string according to the feedback signals, wherein the voltage adjustment amount is a difference between an output voltage of an AC to DC converter resulting from the feedback signal of a lamp string and an output voltage of the AC to DC converter corresponding to the current state of the lamp string leading to the feedback signal;
controlling, by the controller, the detecting circuit to stop generating feedback signals from lamp strings having voltage adjustment amounts above a threshold, and adjusting voltages output by the AC to DC converter according to remaining feedback signals;
outputting, by the AC to DC converter, adjusted voltages to drive the lamp strings, so that all the lamp strings work at a rated current.

Assignees

• Hisense Electric Co Ltd

Inventors

• Pang Zhenhua
• Xin Xiaoguang
• Xu Aichen
• Qiao Mingsheng

Classifications

• G09G3/342 Primary

  using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines · CPC title

• G09G2360/145

  the light originating from the display screen · CPC title

• G09G2320/0646

  Modulation of illumination source brightness and image signal correlated to each other · CPC title

• H05B45/37

  Converter circuits · CPC title

• H05B45/46

  having LEDs disposed in parallel lines · CPC title