Display Device Feedback Loop Variable Impedance Stability
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Solution Overview
Problem
Conventional display devices with feedback loops for power supply voltages become unstable and exhibit poor transient response when the panel load changes, leading to voltage divergence.
Innovation Solution
A display device with a feedback circuit that includes a variable impedance and a controller to calculate the panel load based on input image data, generating an impedance control signal to adjust the impedance of the feedback circuit, thereby providing an error signal to the DC-DC converter to maintain stable power supply voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional feedback loop is designed for a particular panel load value, then the power supply voltage can be maintained at the desired level for that specific load, but the transient response becomes worse and the feedback loop becomes unstable when the panel load changes
Solution Approach 1:
The feedback circuit employs a variable impedance element (such as a switchable capacitor or resistor network) that dynamically adjusts its impedance value based on the detected panel load conditions. This dynamic adjustment allows the feedback loop to maintain optimal stability characteristics across different load scenarios, resolving the contradiction between fixed-design stability and load adaptability
Solution Approach 2:
The invention changes the impedance parameter of the feedback circuit in response to panel load variations. By detecting the panel load and correspondingly adjusting the feedback impedance, the system adapts to different operating conditions while maintaining stable voltage regulation, thus solving the contradiction between designed stability and load versatility
2Adaptability or versatility
If the panel load changes, then the feedback loop should adapt to maintain stable voltage, but the conventional feedback loop becomes unstable and the power supply voltage diverges
Solution Approach 1:
The invention implements a closed-loop feedback mechanism where the output voltage is continuously monitored and fed back to the DC-DC converter. The feedback circuit includes a variable impedance element that adjusts based on panel load detection, creating an adaptive feedback system that maintains voltage stability across varying load conditions by continuously correcting deviations from the target voltage
Solution Approach 2:
The feedback circuit automatically detects panel load changes and self-adjusts its impedance without external intervention. This self-service mechanism enables the system to maintain stable power supply voltage under varying load conditions by autonomously adapting the feedback characteristics to match the current operational state
3Device complexity
If a fixed impedance feedback circuit is used, then the circuit design is simple, but the transient response characteristic deteriorates when panel load changes
Solution Approach 1:
The feedback circuit transitions from a static fixed impedance design to a dynamic variable impedance design. By incorporating switchable impedance elements that can be rapidly reconfigured based on load detection, the circuit maintains simplicity in its base structure while adding dynamic adaptability to achieve fast transient response characteristics when panel load changes occur
Data Source
AI summary
A display device includes a display panel including pixels, a data driver providing data signals to the pixels, a scan driver providing scan signals to the pixels, a DC-DC converter converting an input voltage to a power supply voltage and supplying the power supply voltage to the display panel, a feedback circuit having a variable impedance and providing a feedback path of the power supply voltage to the DC-DC converter by receiving the power supply voltage supplied from the DC-DC converter to the display panel and providing an error signal corresponding to a difference between the feedback voltage and a reference voltage to the DC-DC converter, and a controller controlling the data driver and the scan driver, calculating a panel load of the display panel based on input image data, and adjusting the variable impedance of the feedback circuit according to the calculated panel load.