CN115731883A - Dynamic self-adaptive hybrid dimming method - Google Patents

Abstract

The invention relates to a dynamic self-adaptive hybrid dimming method, which comprises the steps that a low-frequency PWM output module controls the PWM duty ratio of a PWM dimming module and a high-frequency PWM output module controls the LED conduction current of an analog dimming module; when the LED backlight brightness is smaller than a set brightness ratio threshold A, the low-frequency PWM output module controls the PWM duty ratio of the PWM dimming module to keep a set duty ratio value B, the high-frequency PWM output module controls the LED conduction current of the analog dimming module to perform linear increment, and the step pitch of the range controlled by the high-frequency PWM output module is smaller than or equal to a set step pitch S; when the LED backlight brightness is larger than or equal to the set brightness ratio threshold value A, the high-frequency PWM output module controls the LED conduction current of the analog dimming module to keep the set current percentage C, the low-frequency PWM output module controls the PWM duty ratio of the PWM dimming module to perform linear increasing from the set duty ratio value B, and the technical scheme is adopted to reduce the brightness under the dark scene and improve the flicker problem under the dark scene on the basis of original hardware.

Description

Dynamic self-adaptive hybrid dimming method

Technical Field

The invention relates to the field of LED dimming, in particular to a dynamic self-adaptive hybrid dimming method.

Background

The backlight of the lcd tv is an important component of the whole tv, so the technology of adjusting the backlight brightness and improving the image quality in various ways has been a problem to be solved in the industry. The existing backlight adjusting technology of the liquid crystal television comprises PWM dimming and analog dimming.

The PWM dimming mode is a modulation mode in which the duty ratio is adjusted by changing the pulse width with a fixed switching frequency. The PWM dimming fully utilizes the visual residual effect of human eyes to achieve the effect of continuous display, but when the PWM duty ratio is low, the PWM dimming is that the on and off are continuously alternated, namely, the flash frequency occurs.

The analog dimming mode is another mode of LED backlight driving. The analog dimming controls the display brightness by adjusting the screen voltage or current, namely, changing the power, wherein the higher the power is, the higher the brightness is; the backlight module has the defect of narrow dimming range, and under a dark scene, the television screen is brighter due to the fact that the current of the lamp bar of the backlight module is larger.

The existing dimming mode provides a mixed dimming mode capable of simultaneously supporting PWM dimming and analog dimming, solves the defects of flicker frequency under the high-brightness condition of the PWM dimming mode and the narrow dimming range of the analog dimming mode, and enables human eyes to obtain the best visual effect. However, how to realize the free switching of PWM dimming and DC dimming under different PWM duty ratios is realized by hardware, and the brightness under a dark scene and the flicker under the dark scene cannot be better adjusted.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a dynamic self-adaptive mixed dimming method for reducing the brightness and improving the flicker problem under the dark scene on the basis of the original hardware.

The invention discloses a dynamic self-adaptive hybrid dimming method which comprises a low-frequency PWM output module and a high-frequency PWM output module, wherein the low-frequency PWM output module controls the PWM duty ratio of the PWM dimming module, and the high-frequency PWM output module controls the LED conduction current of an analog dimming module;

when the LED backlight brightness is smaller than a set brightness ratio threshold value A, the low-frequency PWM output module controls the PWM duty ratio of the PWM dimming module to keep a set duty ratio value B, the high-frequency PWM output module controls the LED conduction current of the analog dimming module to increase linearly, and the step pitch of the range controlled by the high-frequency PWM output module is smaller than or equal to a set step pitch S;

when the LED backlight brightness is larger than or equal to the set brightness ratio threshold value A, the high-frequency PWM output module controls the LED conduction current of the analog dimming module to keep the set current percentage C, and the low-frequency PWM output module controls the PWM duty ratio of the PWM dimming module to perform linear increment from the set duty ratio value B.

In a further refinement, the set brightness ratio threshold a is 75%, the set duty ratio value B is 72%, the set current percentage C is 100%, and the set step S is 1.5%.

Compared with the prior art, the invention has the beneficial effects that: two PWM output modules are adopted, the low-frequency PWM output module controls the PWM duty ratio of PWM dimming, and the high-frequency PWM output module controls the LED conduction current of analog dimming, so that the brightness under a dark scene is effectively reduced and the flicker problem under the dark scene is improved.

Drawings

The drawings described herein are for the purpose of providing a further understanding of the present application, and in which:

FIG. 1 is a schematic flow chart of a method according to an embodiment of the present invention;

fig. 2 is a dimming linearity diagram according to an embodiment of the invention.

Detailed Description

Referring to fig. 1, a dynamic adaptive hybrid dimming method according to an embodiment includes a low-frequency PWM output module and a high-frequency PWM output module, where the low-frequency PWM output module controls a PWM duty ratio of the PWM dimming module, and the high-frequency PWM output module controls an LED on current of an analog dimming module;

when the LED backlight brightness is less than 75%, the low-frequency PWM output module controls the PWM duty ratio of the PWM dimming module to keep 72%, the high-frequency PWM output module controls the LED conduction current of the analog dimming module to linearly increase, and the step pitch of the range controlled by the high-frequency PWM output module does not exceed 1.5%;

when the LED backlight brightness is larger than or equal to 75%, the high-frequency PWM output module controls the LED conduction current of the analog dimming module to be kept at 100%, and the low-frequency PWM output module controls the PWM duty ratio of the PWM dimming module to be linearly increased from 72%.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims (2)

1. A dynamic self-adaptive hybrid dimming method is characterized by comprising a low-frequency PWM output module and a high-frequency PWM output module, wherein the low-frequency PWM output module controls the PWM duty ratio of the PWM dimming module, and the high-frequency PWM output module controls the LED conduction current of an analog dimming module;

when the LED backlight brightness is smaller than a set brightness ratio threshold A, the low-frequency PWM output module controls the PWM duty ratio of the PWM dimming module to keep a set duty ratio value B, the high-frequency PWM output module controls the LED conduction current of the analog dimming module to perform linear increment, and the step pitch of the range controlled by the high-frequency PWM output module is smaller than or equal to a set step pitch S;

when the LED backlight brightness is larger than or equal to the set brightness ratio threshold value A, the high-frequency PWM output module controls the LED conduction current of the analog dimming module to keep the set current percentage C, and the low-frequency PWM output module controls the PWM duty ratio of the PWM dimming module to perform linear increment from the set duty ratio value B.

2. The method according to claim 1, wherein the set brightness ratio threshold value a is 75%, the set duty cycle value B is 72%, the set current percentage C is 100%, and the set step S is 1.5%.

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