Display Power Control Circuit Fast Shutdown
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Solution Overview
Problem
Existing display apparatuses face issues with slow power-off times due to peripheral circuits, leading to abnormal display functions like black screens or frozen pictures, as the load voltage remains above the working voltage during shutdown, causing sequence disorders.
Innovation Solution
Incorporating a charging module in the control circuit to quickly charge the capacitor during shutdown, allowing for rapid disconnection of the power supply and preventing voltage rebounds, while using a diode and auxiliary module to enhance charging speed and reduce discharging time, ensuring a smooth power-off process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a peripheral circuit with slow power-on feature is added to protect the load from impulse voltage and current, then the load is protected against impulse damage, but the power-off time is prolonged causing slow power-off and display abnormalities
Solution Approach 1:
The patent divides the power control into two independent circuits: a first control circuit for slow power-on protection and a second control circuit for fast power-off control. This segmentation allows each circuit to perform its specific function without interfering with the other, resolving the contradiction between load protection and fast power-off capability
Solution Approach 2:
The patent introduces a second control circuit as an intermediary that can override the slow power-off behavior of the first control circuit. This intermediary circuit provides a fast discharge path for the capacitor during shutdown, enabling rapid power-off while maintaining the protective slow power-on functionality
2Reliability
If the load is powered off slowly to protect from impulse, then the load protection is maintained, but the voltage remains above working voltage during shutdown causing time sequence disorder and display abnormalities
Solution Approach 1:
The patent separates the power control into distinct circuits with different time constants. The first control circuit handles gradual power-on for protection, while the second control circuit manages rapid power-off for precise sequence control, eliminating the conflict between protection and sequence accuracy
Solution Approach 2:
The system dynamically adjusts the discharge rate of the capacitor based on the operational state. During normal operation, the capacitor charges slowly for protection. During shutdown, the second control circuit activates to provide fast discharge, dynamically changing the time constant to achieve both protection and precise sequencing
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
This solution enables quick power-off and slow power-on capabilities, preventing voltage ditches and sequence disorders, thus ensuring normal display operations by managing the power supply's turn-off and turn-on processes effectively.
Implementation Method 1
a capacitor C1 configured to discharge when the grounding switch 35 is disconnected so as to slowly power on the power supply circuit 1
Implementation Method 2
a diode VD1 configured to maintain a voltage difference between a second end of the first resistor R5 and a second end of the capacitor C1 when the grounding switch 35 is disconnected
Data Source
Figure 1A~1B
Figure 2
Figure 3A~3B
AI summary
The present disclosure describes a display apparatus. The display apparatus includes a power source, a power supply circuit, a load and a control circuit. The power source is configured to supply electric power to the load. The power supply circuit connects the power source and the load respectively, and configured to turn on or off an electric path between the power source and the load. The control circuit connects with the power source and the power supply circuit respectively and configured to control the power source circuit to determine whether the power supply supplies power to the load.