Display Power Loss Detection and Sequential Shutdown Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional liquid-crystal displays face issues during AC power failures, where the control chip's operating voltage decreases, leading to insufficient time for a controlled shutdown, resulting in potential damage due to charge residue and abnormal display behavior upon power resupply.
Innovation Solution
A display apparatus with a power-supply circuit, system-control circuit, and power-loss-detection circuit that converts AC voltage to DC voltage and detects power losses, allowing for a predetermined shutdown procedure to sequentially turn off the backlight and display panel, ensuring timely discharge and preventing damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the control chip continues to operate during AC power failure, then the firmware can execute normal shutdown procedures, but the operating voltage decreases below the minimum required voltage causing the control chip to stop working prematurely
Solution Approach 1:
The patent applies preliminary action by detecting the power loss event before the control chip voltage drops below the minimum operating level. The detection circuit monitors the DC voltage from the power supply circuit and triggers the shutdown sequence while the control chip still has sufficient voltage to operate, allowing the firmware to execute the predetermined shutdown procedure properly before power is completely lost.
2Reliability
If the display panel is turned off quickly during power loss, then the control chip can stop working before voltage drops too low, but the display panel does not have sufficient time to discharge electric charges resulting in charge residue
Solution Approach 1:
The patent uses preliminary action by initiating the shutdown sequence while the control chip still has sufficient operating voltage. This timing allows the firmware to first turn off the backlight module and display signal, then provide an extended discharge period for the display panel capacitors before the power supply is completely disconnected, preventing charge residue without waiting for natural discharge.
Solution Approach 2:
The patent applies skipping by rushing through the shutdown sequence in a specific order: first turning off the backlight module and display signal while the control chip is still operational, then immediately followed by disabling the display panel power with an extended discharge period. This rushed sequence ensures the display panel has sufficient discharge time without requiring the control chip to remain operational throughout the entire process.
3Productivity
If AC power is repeatedly turned off and re-supplied without proper shutdown, then the display apparatus can be quickly restored, but the display panel may display abnormally and suffer permanent damage
Solution Approach 1:
The patent applies preliminary action by detecting power loss events and executing a predetermined shutdown procedure that properly discharges the display panel capacitors before power is completely disconnected. This preliminary shutdown sequence prevents charge residue accumulation that would cause abnormal display behavior or permanent damage upon repeated power cycling, while still allowing quick restoration by simply reapplying AC power.
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
The solution enables rapid detection of power losses and execution of a controlled shutdown, ensuring the display panel is properly powered down, preventing damage and ensuring safe operation during AC power failures.
Implementation Method 1
The power-supply circuit is configured to convert an alternating current (AC) voltage to a direct current (DC) voltage
Implementation Method 2
The power-loss detection circuit determines whether the DC voltage is lower than or equal to a trigger voltage
Data Source
AI summary
A display apparatus is provided. The display apparatus includes a display panel, a backlight module, a power-supply circuit, and a system-control circuit. The display panel is configured to display an image signal. The backlight module is configured to provide backlight to the display panel. The power-supply circuit is configured to convert an alternating current (AC) source to a direct current (DC) voltage. The system-control circuit includes a power-loss-detection circuit and a display controller. The power-loss-detection circuit is configured to detect whether the DC voltage from the power-supply circuit has a power-loss event. The display controller is configured to control the display panel and the backlight module. In response to the power-loss-detection circuit detecting that the DC voltage has the power-loss event, the display controller performs a predetermined shutdown procedure to sequentially turn off the backlight module and the display panel.