Pixel Driver Noise Isolation via Segmented Power Supply
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Solution Overview
Problem
Pixel drivers in display panels face issues with noise interference from the power source, affecting the compensation voltage and resulting in incorrect brightness of light emitting elements like OLEDs.
Innovation Solution
A pixel driver circuit comprising a driving circuit, data input circuit, first switch circuit, and second switch circuit, where the first switch circuit provides a first voltage for data input and compensation, and the second switch circuit provides a second voltage for driving the pixel element, isolating the data input from noise in the power source.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single power source is used for both data input and emission periods, then the device complexity is reduced, but the noise from the power source interferes with the compensation voltage affecting the light emitting element brightness
Solution Approach 1:
The power supply system is segmented into two separate power sources: a first power source for providing voltage during the data input period and a second power source for providing voltage during the emission period. This segmentation isolates the noise from the second power source during emission, preventing interference with the compensation voltage and light emitting element operation.
Solution Approach 2:
The first switch circuit and second switch circuit act as intermediaries that selectively connect the driving circuit to different power sources based on the operational period. During data input, the first switch connects to the first power source; during emission, the second switch connects to the second power source, thereby mediating the noise isolation between power sources and sensitive circuit nodes.
2Object-affected harmful factors
If different power sources are used for data input and emission periods, then the noise interference is eliminated, but the device complexity increases due to additional switch circuits
Solution Approach 1:
The first switch circuit and second switch circuit are merged into a unified switching mechanism that controls power source selection. Both switches share common control logic and are integrated with the existing driving circuit architecture, allowing noise isolation functionality to be added without proportionally increasing overall device complexity.
Solution Approach 2:
The first and second switch circuits are designed to perform multiple functions: they not only select between different power sources but also control the timing of data input and emission periods, and provide protection for the driving circuit during transitions. This multi-functionality reduces the need for additional dedicated components.
3Stability of the object's composition
If the first switch circuit remains on during emission period, then the data input circuit continues to receive voltage, but the noise from the power source affects the compensation voltage and brightness accuracy
Solution Approach 1:
The switching between first and second power sources is implemented as a periodic action synchronized with the display refresh cycle. The first switch circuit is turned off and the second switch circuit is turned on during the emission period, creating distinct operational phases that prevent noise contamination while maintaining continuous power supply through seamless transitions.
Solution Approach 2:
The first switch circuit is turned off before the emission period begins, and the second switch circuit is turned on in advance to ensure clean power supply to the driving circuit during emission. This preliminary switching action prevents any potential noise interference from the second power source from affecting the compensation voltage that determines light emitting element brightness.
Data Source
AI summary
A pixel driver includes a driving circuit, a data input circuit, a first switch circuit and a second switch circuit. A driving circuit is configured to provide a driving current to drive a pixel element during an emission period. A data input circuit is electrically coupled to the driving circuit, and is configured to receive a data voltage during a data input period. A first switch circuit is electrically coupled to the driving circuit. The first switch circuit is turned on to provide a first voltage to the driving circuit during the data input period. A second switch circuit is electrically coupled to the driving circuit. The second switch circuit is turned on to provide a second voltage to the driving circuit during the emission period, and the first switch circuit is turned off during the emission period.