Route Protection Circuit for LCD Short Circuit Prevention
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Solution Overview
Problem
Liquid crystal displays (LCDs) are prone to damage due to short circuits in the wire on array and gate on array route circuits, as the existing power ICs do not cut off power when current does not exceed the threshold value, leading to potential burning of the liquid crystal panel.
Innovation Solution
A route protection circuit comprising a detection circuit with an optocoupler and current-limiting resistance, and a feedback circuit with a voltage comparator and switch, which detects short circuits and sends a disable signal to the power supply management circuit to prevent power delivery, thereby preventing damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the power IC uses current threshold protection, then the power IC can protect itself from overload, but the liquid crystal panel will be damaged when short circuit current does not exceed the threshold
Solution Approach 1:
The patent introduces an optocoupler as an intermediary component between the power IC and the load circuit. The optocoupler's light-emitting diode is connected in parallel with the load, and when a short circuit occurs, the current through the optocoupler changes, causing the phototransistor to conduct and trigger the protection circuit. This intermediary mechanism enables detection of short circuits that would otherwise not exceed the power IC's current threshold.
Solution Approach 2:
The patent implements a feedback protection circuit that continuously monitors the operating state through the optocoupler. When the phototransistor detects abnormal current conditions via light signal changes, it provides feedback to the power IC's enable terminal, causing the power IC to shut down. This closed-loop feedback mechanism ensures the power IC can respond to short circuit conditions that bypass traditional current threshold protection.
2Device complexity
If no additional protection circuit is added, then the device complexity is low, but the route circuits will be burned when short circuit occurs
Solution Approach 1:
The optocoupler serves as a compact intermediary that provides comprehensive short circuit protection without requiring complex additional circuits. By utilizing the optocoupler's inherent current-transfer ratio characteristics and connecting it in parallel with the load, the patent achieves protection of both the power IC and route circuits with minimal additional components.
Solution Approach 2:
The protection circuit designed in the patent serves multiple functions simultaneously: it protects the power IC from overload, protects the route circuits from short circuit damage, and enables detection of short circuits that would otherwise bypass current threshold protection. This multi-functional approach achieves comprehensive protection without proportionally increasing circuit complexity.
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
Effectively prevents the wire on array and gate on array route circuits from being burned by disabling the power supply management circuit when a short circuit is detected, thus protecting the liquid crystal panel from damage.
Implementation Method 1
The detection circuit comprises an optocoupler and a current-limiting resistance, wherein a first input end of the optocoupler is employed to couple to another end of the voltage level shift circuit, and a second input end of the optocoupler is employed to couple to the wire on array route circuit or the gate on array route circuit
Implementation Method 2
the feedback circuit comprises a voltage comparator and a switch, and a negative end of the voltage comparator is coupled to a common end of the optocoupler and the current-limiting resistance, and a positive end of the voltage comparator is employed to input a reference voltage
Data Source
AI summary
The circuit of the present invention comprises a detection module and a feedback module, wherein an output end of a power supply management module is coupled to one end of a voltage level shift module, and the other end of the voltage level shift module is coupled to a first end of the detection module, and a second end of the detection module is coupled to a WOA route module or a GOA route module, and a third end of the detection is coupled to one end of the feedback module, and the other end of the feedback module is coupled to an enable end of the power supply management module, and the detection module detects whether the WOA route module or the GOA route module is short, and feeds back a short signal; the feedback module receives the short signal, and sends a disable signal to the enable end.