LED backlight drive circuit, liquid crystal display device and drive circuit

A technology of backlight driving circuit and LED light bar is applied in the field of driving circuit, which can solve the problems such as inability to achieve, and achieve the effect of simple circuit.

CN102646396BActive Publication Date: 2015-02-11CHANGSHA HKC OPTOELECTRONICS CO LTD
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Publication Date
2015-02-11

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Abstract

An LED backlight driving circuit and a driving method therefor. The driving circuit comprises a power supply module, an LED light strip coupled with an output end of the power supply module, a dimming module coupled with an output end of the LED light strip, and a toggle switch. A first input end of the toggle switch is coupled with the output end of the LED light strip, while a second input end is coupled with a feedback voltage (Vmin), and an output end is coupled with the power supply module. The toggle switch switches to the first input end when the dimming module is turned on, and switches to the second input end when the dimming module is turned off. The present invention allows an LED to work normally in a short dimming cycle.
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Description

technical field

[0001] The invention relates to the field of liquid crystal display, and more specifically relates to an LED backlight driving circuit, a liquid crystal display device and a driving circuit. Background technique

[0002] With the maturity of LED technology and the gradual reduction in cost, more and more liquid crystal display devices use LEDs as backlight sources. The driving of LEDs is different from traditional power driving. Generally, pulse width modulation technology (PWM) is used to adjust the brightness. Such as figure 1 As shown, when the LED driver is in the dimming state, when the PWM of the dimming signal is ON, the switch tube at the power supply end conducts and transmits energy to the back-end capacitor CP2 and the LED light bar. When the dimming signal is OFF, the drive circuit Stop working, at this time the LED is also off.

[0003] When the PWM is OFF for too long, the charge on the capacitor will still be consumed by the leakage current o...

Examples

Embodiment Construction

[0020] The present invention will be further described below in conjunction with the accompanying drawings and preferred embodiments.

[0021] The invention discloses an LED backlight driving circuit and a liquid crystal display device based on the LED backlight driving circuit.

[0022] Such as figure 2 As shown, the LED backlight driving circuit includes a power module, an LED light bar coupled to the output end of the power module, a dimming module coupled to the output end of the LED light bar, a comparator, and a switch. The first input terminal SW1 of the switch is coupled to the output terminal of the LED light bar, and the second input terminal SW2 is coupled to a feedback voltage V min ; Its output terminal is coupled to the power supply module through a comparator; the switching switch is switched to the first input terminal when the dimming module is turned on; it is switched to the second input terminal when the dimming module is turned off.

[0023] The power m...