Over-Current Protection Circuit for Display Devices
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Solution Overview
Problem
Display devices face damage due to over-current issues caused by short-circuit defects between driving voltage lines, and existing over-current protection circuits can malfunction if the reference signal is abnormal, leading to abnormal operations.
Innovation Solution
A display device with a protection enable circuit that detects changes in the gate reference signal and generates a protection enable signal only when the signal periods remain consistent, preventing undesired over-current protection operations even if the reference signal is abnormal, by using an internal clock generator, clock counter, and protection-enable-signal generator to determine time differences between signal periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an over-current protection circuit is implemented to detect over-current and stop driving the display panel, then the display panel is protected from damage, but the circuit may perform abnormal operations and fail to operate normally when the reference signal is abnormal
Solution Approach 1:
The patent applies preliminary action by detecting the period of the gate reference signal in advance before performing over-current protection operations. The protection enable circuit measures the period of the gate reference signal and compares it with a reference period to determine whether to enable the over-current protection function. This preliminary period detection prevents abnormal operations caused by abnormal reference signals while ensuring the protection circuit operates normally under correct conditions
Solution Approach 2:
The patent implements feedback by using the detected period of the gate reference signal to control the enabling of the over-current protection function. The protection enable circuit continuously monitors the period and adjusts the protection function accordingly - enabling it when the period matches the reference period and disabling it when there is a mismatch. This feedback mechanism ensures the protection circuit operates reliably only when the reference signal is normal
2Object-affected harmful factors
If the over-current protection circuit operates based on the reference signal, then over-current detection is performed, but abnormal reference signals cause the protection circuit to malfunction
Solution Approach 1:
The patent applies preliminary action by validating the reference signal through period detection before allowing the protection circuit to operate. The protection enable circuit measures the period of the gate reference signal and compares it with a predetermined reference period. Only when the periods match does the circuit enable the over-current protection function, preventing malfunction caused by abnormal reference signals while maintaining protection against over-current damage
Solution Approach 2:
The patent introduces an intermediary mechanism - the period detection and comparison circuit - that mediates between the reference signal and the over-current protection function. This intermediary validates the reference signal by checking its period before allowing it to control the protection circuit, thereby preventing abnormal reference signals from causing protection circuit malfunction while ensuring proper protection when the reference signal is valid
Data Source
AI summary
A display device includes a display panel including a plurality of pixels, a controller which generates a gate reference signal, a gate control circuit which outputs a gate driving signal based on the gate reference signal, and a gate driving circuit which provides gate signals to the plurality of pixels based on the gate driving signal. The gate control circuit includes a protection enable circuit which detects a first period of the gate reference signal, determines whether the period of the gate reference signal is changed, and generates a protection enable signal when the first period of the gate reference signal is not changed, and an over-current protection circuit which generates an over-current occurrence signal by detecting an over-current of the gate driving signal, and stops outputting the gate driving signal based on the over-current occurrence signal and the protection enable signal.