Level Shifter Overcurrent Protection Circuit for Display Panels
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Solution Overview
Problem
Display devices face the challenge of overcurrent generation due to short circuits, which can lead to damage or ignition of the panel and gate driver, necessitating an effective overcurrent protection (OCP) circuit to differentiate between normal and overcurrent peak currents.
Innovation Solution
A display device incorporating a level shifter with an overcurrent protection circuit that sets a non-sensing time period for normal peak current generation and activates sensing during remaining periods, allowing differential sensing of overcurrent and outputting a protection signal to prevent damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an overcurrent protection circuit continuously senses current to detect overcurrent conditions, then reliability of circuit protection is improved, but normal peak current generated during regular operation is falsely detected as overcurrent, causing unnecessary protection actions
Solution Approach 1:
The patent implements periodic sensing by defining specific sensing time periods during which the overcurrent protection circuit actively monitors current, and non-sensing time periods during which sensing is suspended. This periodic operation allows the system to distinguish between normal peak current (occurring during non-sensing periods) and actual overcurrent conditions (detected during sensing periods), thereby improving detection accuracy while maintaining protection reliability
Solution Approach 2:
The patent applies preliminary action by setting the non-sensing time period to coincide with the expected duration of normal peak current generation. By proactively disabling the sensing function during this predetermined period, the system prevents false detection of normal operational peaks as overcurrent conditions, while ensuring sensing is active during periods when overcurrent detection is critical
2Object-affected harmful factors
If the overcurrent protection circuit senses current during all periods, then any overcurrent condition is detected, but normal peak current is misidentified as overcurrent leading to false protection signals
Solution Approach 1:
The sensing operation is divided into periodic sensing and non-sensing intervals. During non-sensing time periods when normal peak current is expected, the sensing function is disabled to prevent false protection signals. During sensing time periods, the circuit actively monitors for overcurrent conditions, ensuring real damage prevention without triggering false alarms from normal operational peaks
3Measurement precision
If the sensing operation is disabled during normal peak current generation, then false overcurrent detection is prevented, but overcurrent occurring during peak current periods may not be detected
Solution Approach 1:
The system uses preliminary action by pre-defining the non-sensing time period based on expected normal peak current duration and timing. This allows the sensing function to be selectively disabled only when normal peaks are anticipated, while maintaining active sensing during all other periods when overcurrent detection is critical, thus balancing accuracy with comprehensive protection coverage
Data Source
AI summary
A display device includes: a timing controller generating and supplying first timing control signals, a level shifter generating and supplying gate control signals using the first timing control signals, a gate driver separately driving gate lines of a panel using the gate control signals, and an output circuit outputting the gate control signals, the level shifter including an overcurrent protection circuit (OPC) connected to the output circuit, the overcurrent protection circuit sensing overcurrent generation in the level shifter and overcurrent generation in a target circuit through the output circuit to output an overcurrent protection signal, wherein the level shifter: sets a time period to be a non-sensing time period, turns off a sensing operation of the OPC during the non-sensing time period, and turning on the sensing operation of the OPC during other periods, and wherein the OPC: turns on the sensing operation, and senses the overcurrent generation.