LCD Voltage Control Circuit for VCOM-GAMMA Timing Synchronization

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Solution Overview

Problem

Conventional voltage control circuits in liquid crystal displays (LCDs) fail to achieve consistent timing between VCOM and GAMMA voltages, leading to image abnormalities.

Innovation Solution

A voltage control circuit incorporating an I2C control module, digital-to-analog conversion module, amplification module, and a timing control module with comparators and an AND gate comparator to control the timing of the VCOM signal, ensuring synchronization with the GAMMA signal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional voltage control circuit is used, then the circuit structure is simple, but the timing of VCOM and GAMMA voltages cannot be synchronized, leading to image abnormalities

Engineering Contradiction:

Improvetiming synchronizationVSAvoidcircuit structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The timing control module performs preliminary action by generating a timing control signal before the voltage output, using comparators to detect voltage levels and an AND gate to synchronize the timing of VCOM and GAMMA voltages, ensuring proper sequencing before the main voltage output occurs

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The timing control module acts as an intermediary between the voltage control circuit and the output stage, using comparators and an AND gate as mediating components to synchronize timing signals without directly controlling the voltage magnitude, thus maintaining circuit modularity

Inventive Principle:

Principle #24Intermediary (Mediator)

2Manufacturing precision

If timing control is added to synchronize VCOM and GAMMA voltages, then timing synchronization is achieved, but the circuit complexity increases

Engineering Contradiction:

Improvevoltage timing precisionVSAvoidcircuit components

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The timing control module is segmented into independent functional components: first and second comparators for voltage level detection, and an AND gate for timing synchronization. This segmentation allows each component to perform a specific function, making the circuit easier to design, analyze, and manufacture with high precision

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The circuit uses parameter changes in voltage levels detected by comparators to control timing. When input voltages reach specific threshold levels, the comparators change their output states, which the AND gate then uses to generate synchronized timing signals, achieving precise voltage timing control

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12380868B2Voltage control circuit including a timing control module controlling whether a second voltage signal is outputted, and display panel

Publication Date: 2025.08.05 SHENZHEN CHINA STAR OPTOELECTRONICS SEMICON DISPLAY TECH CO LTD

AI summary

A voltage control circuit comprises a timing control module; the timing control module comprises a first comparator, a second comparator, and an AND gate comparator, two input ends of the AND gate comparator are respectively connected to the output end of the first comparator and the output end of the second comparator, and the output end of the AND gate comparator is used for controlling the output of a second voltage signal; and the timing control module can implement control on the timing of the second voltage signal.