Light-emitting diode current sharing control circuit

A technology of light emitting diodes and control circuits, applied in the field of light emitting diode current sharing control circuits, can solve the problems of unequal luminous intensity, unequal current, and uneven brightness of light bars, and achieve the effect of solving the difficulty of current sharing

CN108922480APending Publication Date: 2018-11-30GUANGZHOU SHIYUAN ELECTRONICS CO LTD
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2018-11-30

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Abstract

The invention discloses a light-emitting diode current sharing control circuit, and relates to the technical field of backlight driving. The circuit comprises: a first sub-control circuit with an independent power supply, 2n-1 second sub-control circuits and a third sub-control circuit; when n=1, the first sub-control circuit and the second sub-control circuit are coupled through a first current sharing inductor, and the second sub-control circuit and the third sub-control circuit are coupled through a second current sharing inductor; when n is greater than 1, the first sub-control circuit andthe first second sub-control circuit are coupled through the first current sharing inductor, the i-th second sub-control circuit and the i-1-th second sub-control circuit are coupled through third current sharing inductors; the third sub-control circuit and the 2n-1-th second sub-control circuit are coupled through a second current sharing inductor, 2<=i<=2n-1. The circuit realizes the current sharing of the odd street light strips, and improves the uniformity of illumination and the image quality displayed by the display device.
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Description

technical field

[0001] The invention relates to the technical field of backlight driving, in particular to a light emitting diode current sharing control circuit. Background technique

[0002] A display device, such as a Liquid Crystal Display (LCD), has become an important part of a terminal product, and the brightness of a backlight of the LCD has a great influence on its imaging effect. A light emitting diode (Light Emitting Diode, LED) is widely used as a backlight light emitting device of an LCD due to its remarkable advantages of low power consumption and long life.

[0003] However, when using a voltage source to drive multiple LED light strips, the current through each light strip may be unequal due to the difference in the forward voltage of each light bead, so that the luminous intensity of each light strip is not equal. resulting in uneven brightness. Therefore, the use of the LED light bar needs to ensure that the current of each light bar can be balanced, so a...

Examples

Embodiment 1

[0018] figure 1 It is a schematic structural diagram of a light emitting diode current sharing control circuit in Embodiment 1 of the present invention. This embodiment is applicable to the case of carrying out current sharing on odd-numbered channels of a backlight circuit.

[0019] The odd number of backlight circuits (3, 5, 7, 9...) has always been a difficult point in current sharing. In this embodiment, the output of the odd number of backlight circuits is averaged by adding a current sharing inductance and / or a film capacitor. Stream processing makes the error between the three output currents small (within 2%). When the voltage is different between the light bars due to the difference of the lamp beads, it can also ensure that the current error of each channel is very small, and achieve a good current sharing effect. Specifically, when there is a difference between the output currents of each channel, the voltage of each LED light bar is adjusted through the difference...