Display Device Power Supply Segmentation for Noise Isolation
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Solution Overview
Problem
High-frequency radiation noise from signal selection circuits in liquid crystal display devices, particularly in portable electronic devices, affects radio frequency circuits and reduces reception sensitivity due to increased control frequency with higher resolution and time-division driving.
Innovation Solution
A display device configuration that includes a gate driver, first and second control signal output circuits, and a signal selection circuit, where at least one of these components operates with power from a boosted power supply, reducing switching noise propagation and radiation noise by using separate power supply systems for the gate driver and control signal output circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If time-division driving is performed with increased resolution and frame rate, then display performance is improved, but control frequency increases causing high-frequency radiation noise
Solution Approach 1:
The patent divides the power supply system into separate sections: a first power supply for the gate driver and a second power supply for the signal selection circuit. This segmentation isolates the high-frequency switching noise generated by the signal selection circuit from the gate driver, preventing radiation noise while maintaining high-resolution display performance through time-division driving
Solution Approach 2:
The patent introduces a capacitor connected between the first and second power supplies as an intermediary element. This capacitor acts as a noise filter and isolation barrier, blocking high-frequency switching noise from propagating between the two power supply systems while allowing stable voltage operation
2Speed
If control frequency of signal selection circuit is increased, then driving speed is improved, but switching noise propagation increases
Solution Approach 1:
The patent segments the power supply into separate first and second power supplies for different circuits. The signal selection circuit operating at high frequency has its own isolated power supply, preventing switching noise from affecting other components while maintaining high driving speed
Solution Approach 2:
The capacitor between power supplies serves as a noise-blocking intermediary that allows high-frequency signals to operate at full speed while preventing noise propagation to other circuits
3Power
If voltage of control signal is level shifted, then driving force of transistor is increased, but switching noise is generated
Solution Approach 1:
The patent applies separate power supplies to different circuits performing voltage level shifting. The signal selection circuit has its own isolated power supply, allowing voltage level shifting for enhanced driving force while containing switching noise within the isolated circuit
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 effectively suppresses radiation noise and maintains high-frequency signal integrity, enhancing the reception sensitivity of portable electronic devices by isolating switching noise generated during time-division driving operations.
Implementation Method 1
voltage of the first power supply being boosted by a boosting circuit
Data Source
AI summary
A display device, comprising: a plurality of pixels arranged in a matrix (row-column configuration) in a display area; a scanning line that is coupled to each of the pixels aligned in a row direction in the display area, and to which a scanning signal is supplied; a signal line that is coupled to each of the pixels aligned in a column direction in the display area, and to which a pixel signal is supplied; a gate driver that supplies the scanning signal to the scanning line; a signal selection circuit that separates the pixel signal that is time-division multiplexed to an image signal; a first control signal output circuit that outputs a first control signal supplied to the gate driver; and a second control signal output circuit that outputs a second control signal supplied to the signal selection circuit.