LCD Test Circuit Internal Voltage Generation
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Solution Overview
Problem
The existing high voltage test circuits for LCD devices require a test voltage generator, increasing the overall cost due to the need for additional components and complexity.
Innovation Solution
A test circuit that generates test voltages internally within the LCD device's circuit board, using a power supply to provide DC voltages that are converted and modulated to achieve higher test voltages without the need for an external test voltage generator, thereby reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a test voltage generator is used to generate high test voltages for LCD devices, then the testing function is achieved, but the cost and device complexity increase
Solution Approach 1:
The LCD device's own circuit board is made to generate the high test voltages needed for testing through its existing power supply and voltage conversion circuits, eliminating the need for external test voltage generators. The device tests itself using internal resources.
Solution Approach 2:
The power supply and voltage conversion circuits on the LCD device's circuit board are designed to serve dual purposes: normal operation during regular use and high voltage generation during testing. This multi-functionality eliminates the need for separate dedicated test equipment.
2Reliability
If a test voltage generator is used to provide high test voltages, then the testing capability is achieved, but the overall cost increases
Solution Approach 1:
The LCD device generates its own test voltages using internal circuits, eliminating the need to purchase and integrate external test voltage generators, thereby reducing overall system cost.
Solution Approach 2:
The testing functions are merged into the existing circuit board design, combining normal operation circuits with test function generation in a single integrated system, reducing component count and cost.
3Measurement precision
If external test voltage generators are used for each LCD device, then accurate voltage testing is achieved, but the quantity of components increases
Solution Approach 1:
Each LCD device generates its own test voltages internally, eliminating the need for external test voltage generators and reducing the total component quantity required in the test system.
Solution Approach 2:
The existing power supply and voltage conversion circuits perform both normal operation and high voltage generation functions, eliminating the need for separate dedicated test components.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution allows for cost-effective high voltage testing of LCD devices by eliminating the requirement for a separate test voltage generator, while still enabling the display panel to show test images with predetermined test voltages higher than normal operating voltages.
Implementation Method 1
A test circuit that generates test voltages internally within the LCD device's circuit board, using a power supply to provide DC voltages that are converted and modulated to achieve higher test voltages
Data Source
AI summary
A test circuit for an electronic device including a liquid crystal display (LCD) device. The LCD device includes a pulse width modulator (PWM) to provide voltages to a display panel of the LCD device, a plurality of feedback circuits to output feedback voltages to the PWM, and a power supply to provide an operating voltage for the PWM. When the electronic device is in a test mode, the feedback circuits respectively decrease the feedback voltages, such that the PWM increases the voltages output to the display panel according to the feedback voltages, the increased voltages reach predetermined test voltages and test the electronic device.