Display Power Supply Switching Noise Reduction
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Solution Overview
Problem
As the resolution of image display apparatuses increases to 2K, 4K, 8K, and 16K, so does power consumption, leading to increased noise during power supply switching, which existing technologies have not effectively addressed.
Innovation Solution
An image display apparatus with a power supply that includes a converter to convert AC voltage to DC voltage and a controller to control switching devices, where the controller adjusts the on-time of switching devices based on input and output voltages to minimize noise during power supply switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the resolution of the display is increased to 2K, 4K, 8K, and 16K, then the image quality and definition are improved, but the power consumption of the display is increased
Solution Approach 1:
The patent applies dynamic control to the switching devices in the power supply converter, adjusting their on-time based on the instantaneous input voltage levels. The controller dynamically modifies the duty cycle of switching devices during different phases of the AC voltage waveform, particularly during zero-crossing periods, to optimize power conversion efficiency and reduce power consumption while supporting high-resolution display requirements
2Power
If the power consumption is increased to support high resolution displays, then the driving capability is improved, but the noise during power supply switching is increased
Solution Approach 1:
The patent implements preliminary anti-action by proactively controlling the switching devices to turn off during zero-crossing periods of the input AC voltage, where the voltage passes through zero. This preventive measure avoids the generation of large switching noise and electromagnetic interference that would occur if switching happened at high voltage levels, thus reducing noise while maintaining sufficient driving power during non-zero-crossing periods
Solution Approach 2:
The controller periodically adjusts the operation of switching devices based on the cyclic nature of the AC input voltage waveform. By detecting zero-crossing points and synchronizing switching operations with the periodic AC cycle, the system reduces noise during critical transition periods while maintaining efficient power conversion during stable voltage periods, effectively managing both power delivery and noise reduction
3Productivity
If the switching frequency is increased to improve power conversion efficiency, then the power efficiency is improved, but the noise during switching is increased
Solution Approach 1:
The controller employs periodic action by synchronizing switching operations with the AC voltage cycle and implementing duty cycle adjustments at specific phases. This periodic control strategy maintains high conversion efficiency through frequent switching while concentrating noise-reduction actions at predictable zero-crossing intervals, allowing the system to achieve both high efficiency and noise management
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 reduces noise during power supply switching by optimizing the on-time of switching devices, thereby improving power efficiency and reducing noise levels in high-resolution display systems.
Implementation Method 1
a converter to convert input AC voltage into DC voltage
Data Source
AI summary
An image display apparatus is disclosed. The image display apparatus includes a display and a power supply configured to supply driving voltage to the display, wherein the power supply includes a converter to convert input AC voltage into DC voltage and a controller to control the converter, the converter includes a first leg including a first switching device and a second switching device connected to each other in series and a second leg including a first diode and a second diode connected to each other in series, the first diode and the second diode connected to the first leg in parallel, and the controller controls on time of the first switching device to gradually increase from a first level to a second level for a first period for which the input AC voltage rises after a zero crossing point.