Low-grayscale optimization PWM algorithm for LED driving chip

A technology of LED drive and PWM algorithm, applied in the direction of instruments, static indicators, etc., can solve the problems of uneven color display, easy to appear low gray spots, etc., and achieve the effect of reducing coupling interference and improving display effect

Inactive Publication Date: 2020-12-22
CHINA KEY SYST & INTEGRATED CIRCUIT
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] The purpose of the present invention is to provide a low-grayscale optimization PWM algorithm for LED driver chips to solve the problems of low-gray pits and uneven color display when displaying low-gray pictures in existing large LED screens

Method used

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  • Low-grayscale optimization PWM algorithm for LED driving chip
  • Low-grayscale optimization PWM algorithm for LED driving chip
  • Low-grayscale optimization PWM algorithm for LED driving chip

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Embodiment 1

[0033] The invention provides a low-gray-scale optimized PWM algorithm for an LED driver chip, comprising the following steps:

[0034] Step S31, the 2 required for displaying N-bit grayscale data N GCLKs are evenly distributed to 2 L In sub-periods, each sub-period includes 2 H GCLK, N, H, L are positive integers, N=H+L;

[0035] Step S32, setting the optimization level Opt, Opt is a non-negative integer, and the minimum width of PWM in each sub-cycle is set to 2 Opt ;

[0036] Step S33, when the grayscale data is 2 L+Opt When the integer multiple of , the grayscale data is evenly distributed to 2 L in a sub-cycle;

[0037] Step S34, when the grayscale data is not 2 L+Opt When the integer multiple of the binary grayscale data is multiplied by 2 from the highest bit to the (L+Opt+1) bit L+Opt , and evenly distribute the resulting product to 2 L in a sub-cycle;

[0038] Step S35, on the basis of step S34, divide by 2 with the low (L+Opt) bit of binary gray scale data O...

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Abstract

The invention discloses a low-grayscale optimization PWM algorithm for an LED driving chip, and belongs to the field LED display. The algorithm comprises the steps: averagely distributing 2N GCLKs required for displaying N-bit grayscale data to 2L sub-periods, wherein each sub-period comprises 2H GCLKs, N, H and L are positive integers, and N = H + L; setting an optimization level Opt which is a non-negative integer, and setting the minimum PWM in each sub-period as 2Opt; when the grayscale data is integral multiples of 2L + Opt, averagely distributing the grayscale data to 2L sub-periods; when the grayscale data is not integral multiples of 2L + Opt, multiplying the highest bit to the (L + Opt + 1) th bit of the binary grayscale data by 2L + Opt, and averagely distributing the obtained product to 2L sub-periods; dividing the low (L + Opt) bit of the binary grayscale data by the 2Opt to obtain a quotient D and a remainder R; allocating R GCLKs in the zeroth sub-period; and dividing theremaining gray values into D groups so that each group has 2opt GCLKs, and and distributing the GCLKs to the sub-period 1 to the sub-period 2L1 by taking the group as a unit. The display effect during low grayscale can be effectively improved, and the problems of low grayscale pocking marks, low grayscale display unevenness and the like are solved.

Description

technical field [0001] The invention relates to the technical field of LED display, in particular to a low-gray-scale optimized PWM algorithm for an LED drive chip. Background technique [0002] LED, also known as light-emitting diode, has the advantages of high energy efficiency, low power consumption, low cost, and environmental protection. LED display has the advantages of good display effect, customization, and high maintainability, and has a good prospect in the indoor and outdoor display large-screen market. [0003] Now the LED large-screen driver chips on the market generally use PWM dimming technology to control the LED drive current by adjusting the pulse width of the digital signal, thereby controlling the brightness of the LED lamp bead. On the basis of the PWM algorithm, SPWM is developed, that is, the scattered PWM algorithm. figure 1 It is a schematic diagram of the SPWM algorithm commonly used in LED driver chips. This algorithm breaks up the entire displa...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G09G3/32
CPCG09G3/32
Inventor 王震宇范学仕李鸣晓夏云汉
Owner CHINA KEY SYST & INTEGRATED CIRCUIT
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