LCD Common Electrode Short Circuit Detection via Blanking Period Voltage Comparison
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for detecting short circuits in LCD panels have low accuracy due to interference from data lines and gate lines, leading to unreliable over-current protection, which can only trigger when the short circuit current is large.
Innovation Solution
A circuit with a power management integrated circuit and a short circuit determination module that performs difference processing on voltage signals during the blanking period, comparing the voltage drop signal with a reference voltage to accurately detect short circuits, even when the current is small, by using a resistor and a capacitor to filter and charge signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If current detection method is used during scanning period, then detection can be performed continuously, but detection accuracy deteriorates due to interference from data lines and gate lines
Solution Approach 1:
The patent performs short circuit detection during the blanking period before the scanning period begins. By conducting the detection in advance during the blanking period when no scanning signals are active, the measurement is taken before interference from data lines and gate lines can affect the common electrode wiring, thus ensuring high detection accuracy without continuous scanning interference
Solution Approach 2:
The patent extracts the detection function from the continuous scanning period and isolates it to occur only during the blanking period. This separation removes the detection operation from the interfering scanning environment, allowing accurate measurement of voltage signals without the harmful effects of simultaneous data line and gate line activity
2Reliability
If detection threshold is set high for reliability, then false positives are reduced, but detection capability for small short circuits deteriorates
Solution Approach 1:
By performing detection during the blanking period before scanning begins, the patent obtains a clean baseline voltage signal without interference. This preliminary measurement during the interference-free period enables setting of appropriate detection thresholds that can reliably identify even small short circuits without false positives from scanning period noise
Solution Approach 2:
The patent replaces current-based detection with voltage-based detection using a high-impedance voltage divider circuit. This substitution allows measurement of voltage signals with minimal current draw, enabling detection of small short circuits through voltage drop measurements rather than requiring large current flows, thus improving both sensitivity to small faults and reliability
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 enhances the accuracy of short circuit detection in LCD panels, avoiding interference from scanning periods and enabling precise over-current protection, allowing for detection of small short circuit currents and reducing false triggering.
Implementation Method 1
a second voltage signal from the first resistor... The second voltage signal is outputted by the first voltage signal via the first resistor
Implementation Method 2
perform a difference processing on a first voltage signal outputted by the common electrode wiring and a second voltage signal from the first resistor to obtain a voltage drop signal
Data Source
AI summary
A circuit for detecting a short circuit of a common electrode wiring is applied in an LCD panel and includes a common electrode wiring, a short circuit determination module and a resistor. An output terminal of the common electrode wiring is connected with a first terminal of the resistor and an input terminal of the short circuit determination module, and a second terminal of the resistor is connected with an input terminal of the short circuit determination module. The short circuit determination module obtains a voltage drop signal according to a first signal outputted by the common electrode wiring and a second signal from the resistor in a blanking period of the LCD panel, and determines that the common electrode wiring has a short circuit if the voltage value of the voltage drop signal is greater than the voltage value of a reference signal throughout a predetermined period.