Power Supply Circuit Reset Threshold for Display Panel Gate Lines
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Solution Overview
Problem
Conventional power supply circuits fail to effectively reset gate lines in display panels during power-off due to the inability of level shifters to operate normally when the operating voltage drops below a critical level, resulting in incomplete release of residual electric charges and abnormal displays upon power-on.
Innovation Solution
A power supply circuit with a comparison circuit, preset value setting circuit, reset detecting circuit, and reset signal generating circuit that compares voltages to determine a reset threshold, allowing the circuit to output a reset signal before the operating voltage drops too low, ensuring the level shifter can still operate and drive gate lines to release residual charges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the power supply circuit outputs a reset signal before the operating voltage drops to 0 V to simultaneously drive all gate lines, then the residual electric charges in all pixels can be released, but when the operating voltage drops below a critical level, the level shifter cannot operate normally and the gate drive circuit cannot output sufficient gate pulses
Solution Approach 1:
The power supply circuit performs preliminary action by outputting the reset signal before the operating voltage drops to a critical level. The reset signal is generated when the operating voltage is still above the threshold required for the level shifter to operate, ensuring that the gate drive circuit can successfully output gate pulses to reset all gate lines before power completely shuts down.
Solution Approach 2:
The power supply circuit uses feedback from the operating voltage level to control the reset signal generation. By monitoring the operating voltage and comparing it with preset thresholds, the circuit dynamically decides when to generate the reset signal, ensuring optimal timing for the level shifter to operate while still achieving complete gate line reset.
2Productivity
If the reset signal is outputted when the operating voltage is high to ensure level shifter operation, then the gate drive circuit can output sufficient gate pulses, but the reset may not be timely enough before power completely shuts down
Solution Approach 1:
The system performs the reset action in advance by generating the reset signal at an optimal timing point. The reset signal is outputted when the operating voltage is still sufficient for the level shifter to operate, ensuring that all gate lines can be reset before the power completely shuts down, thus avoiding any loss of time for the reset operation.
Solution Approach 2:
The power supply circuit changes the parameter of operating voltage threshold to determine when to generate the reset signal. By using multiple preset voltage thresholds and comparing the operating voltage against them, the circuit optimizes the timing parameter to ensure both timely reset completion and sufficient voltage headroom for the level shifter operation.
Data Source
AI summary
A power supply circuit includes a comparison circuit, a preset value setting circuit, a reset detecting circuit and a reset signal generating circuit. The comparison circuit compares a first and second voltage to output a comparing result. The first and second voltages correspond to a first and second preset value, respectively. When the comparison result shows that the second voltage is greater than the first voltage, the preset value setting circuit outputs the second preset value; otherwise it outputs a third preset value, which is greater than the first preset value. The reset detecting circuit determines whether the operation voltage of the power supply circuit drops to the preset value outputted by the preset value setting circuit, and outputs a control signal accordingly. The reset signal generating circuit determines whether to output a reset signal for resetting gate lines in a display panel based on the control signal.