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LED backlight driving circuit and driving method based on low potential end switch control

A backlight drive circuit and backlight drive technology, applied in the use of semiconductor lamps, static indicators, instruments, etc., can solve the problems of inability to improve the brightness of a single LED light string alone, poor display effect, and increased control difficulty. Eliminate the phenomenon of afterimage, save the cost of circuit structure, and avoid the effect of high current

Active Publication Date: 2022-04-29
X-SIGNAL INTEGRATED CO
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Moreover, the row scan switching at the high potential end needs to be controlled and matched with the column scan switching at the low potential end, which greatly increases the difficulty of control
At the same time, under this LED backlight control mode, due to the large current at the high potential end when switching, the resulting display "ghost" (afterimage) phenomenon is very obvious, even if additional pre-charging control is added, it is difficult to completely eliminate it.
The most obvious defect is that under this LED backlight control method, the brightness of a single LED light string cannot be increased independently, and only the brightness of a group of LED light strings can be improved at the same time.
This makes the display effect not good when providing a special local picture with a short-term brightness surge (such as an explosion picture) under the LED backlight control method.

Method used

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  • LED backlight driving circuit and driving method based on low potential end switch control
  • LED backlight driving circuit and driving method based on low potential end switch control
  • LED backlight driving circuit and driving method based on low potential end switch control

Examples

Experimental program
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Effect test

Embodiment 1

[0060] In this embodiment, every four LED light strings form a group, and the four LED light strings share one constant current module. Since there are four LED light strings sharing the constant current module, in the case that the LED light strings of all channels equally share the constant current module, the upper limit of the duty ratio that can be shared by the LED light strings of each channel is 25%. And the sum of the on-duty ratios of the LEDs of all channels is at most 100%, that is, the sum of all the duty ratios of the constant current modules shared by the four channels is at most 100%.

[0061] However, when the brightness requirement duty cycle of a certain LED light string exceeds 25%, in the LED backlight driving method of this embodiment, the other LED light strings in the same group fail to reach the duty cycle margin of 25% duty cycle. Supplemented to LED light strings that require increased brightness, so that the LED light string breaks through the 25% d...

Embodiment 2

[0066] Same as Embodiment 1, in this embodiment, every four LED light strings form a group, and the four LED light strings share one constant current module. Since four LED light strings share the constant current module, the maximum duty cycle of the LED light strings of each channel is 25% under the condition that the LED light strings of all channels equally share the constant current module. However, when the brightness requirement of a certain LED light string exceeds 25%, in the LED backlight driving method of this embodiment, the duty cycle margin of other LED light strings in the same group that fails to reach the 25% duty cycle is supplemented to the required In the LED light string with increased brightness, the LED light string breaks through the duty ratio limit of 25%.

[0067] For example, the brightness requirements of the LED light strings of channel 1, channel 2, channel 3, and channel 4 are 60%, 15%, 20%, and 25%, respectively. From the above brightness requ...

Embodiment 3

[0074] Same as Embodiment 1, in this embodiment, every four LED light strings form a group, and the four LED light strings share one constant current module. Since there are four LED light strings sharing the constant current module, the maximum duty cycle of the LED light strings of each channel is 25% under the condition that the LED light strings of all channels equally share the constant current module. However, when the brightness requirement of a certain LED light string exceeds 25%, in the LED backlight driving method of this embodiment, the duty cycle margin of other LED light strings in the same group that fails to reach the 25% duty cycle is supplemented to the required In the LED light string with increased brightness, the LED light string breaks through the duty ratio limit of 25%.

[0075] For example, the brightness requirements of the LED light strings of channel 1, channel 2, channel 3, and channel 4 are 60%, 15%, 20%, and 25%, respectively. From the above bri...

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Abstract

The invention discloses an LED backlight driving circuit based on low potential end switch control and a backlight driving method. The LED backlight driving circuit comprises a plurality of LED lamp strings 1, a channel control switch device 2, a constant current module 3, a channel switching control module 4, a signal control unit 5 and an SPI interface unit 6. The high potential end of each LED lamp string 1 is directly connected to an LED driving voltage VLED, the low potential end of each LED lamp string 1 is connected with a channel control switch device 2 and a constant current module 3, and the plurality of channel control switch devices 2 in each group of LED lamp strings are connected to a channel switching control module 4; and the channel switching control module 4 is used for controlling the turn-on duty ratio of the LED lamp strings in the group.

Description

technical field [0001] The invention relates to the technical field of LED display, in particular to an LED backlight driving circuit and a driving method based on low potential end switch control. Background technique [0002] The LED backlight drive in the prior art generally adopts a direct drive mode or a row-column scan drive mode. Such as figure 1 As shown, it is the LED backlight control in the direct drive mode in the prior art. In the LED backlight drive circuit, the positive end (high potential end) of each LED light string is connected to the driving voltage V LED . A line selection control switching device and a constant current module are connected to the negative terminal (low potential terminal) of each LED light string. The advantage of this LED backlight drive circuit in direct drive mode is that it can ensure that each LED light string can achieve 100% brightness display, that is, when a certain LED light string needs maximum brightness output, it only n...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G09G3/34
CPCG09G3/3406G09G3/3413G09G2320/0257Y02B20/30
Inventor 阳冠欧王京孔令新
Owner X-SIGNAL INTEGRATED CO
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