Display Power Supply Circuit With Adaptive Switching Frequency
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Solution Overview
Problem
Display apparatuses face challenges in managing switching frequency to balance output efficiency and prevention of wavy noise (ripple) caused by external changes.
Innovation Solution
An adaptive switching frequency control method is implemented, prioritizing ripple prevention over output efficiency optimization. The method includes a power supply with an output controller that operates in two driving modes: a higher-priority mode for ripple prevention and a lower-priority mode for output efficiency optimization, controlling the switching frequency in real-time based on these factors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the switching frequency is increased to optimize output efficiency, then the output efficiency is improved, but wavy noise (ripple) increases
Solution Approach 1:
The patent implements dynamic switching frequency adjustment by transitioning from a fixed switching frequency to a variable switching frequency that adapts based on operating conditions. The controller dynamically selects between a first switching frequency (optimized for efficiency) and a second switching frequency (optimized for ripple reduction) based on real-time monitoring of output voltage ripple and efficiency metrics, thereby resolving the contradiction between output efficiency and wavy noise prevention.
Solution Approach 2:
The patent changes the parameter of switching frequency from a static value to a dynamically adjustable parameter. By modifying the switching frequency parameter based on calculated efficiency values and monitored ripple conditions, the system can shift between operating points to either maximize output efficiency or minimize wavy noise, thus resolving the technical contradiction between these two opposing requirements.
2Device complexity
If a fixed switching frequency is used, then the control is simple, but the system cannot adapt to external changes to prevent wavy noise
Solution Approach 1:
The patent implements a feedback mechanism where the controller continuously monitors output voltage ripple and calculates efficiency values based on input and output power measurements. This feedback information is used to dynamically adjust the switching frequency, enabling the system to adapt to external changes and prevent wavy noise while maintaining relatively simple control logic through automated decision-making based on predefined criteria.
3Object-affected harmful factors
If the switching frequency is decreased to reduce wavy noise, then the ripple is reduced, but the output efficiency decreases
Solution Approach 1:
The patent resolves this contradiction by making the switching frequency dynamic rather than fixed. The system transitions between a lower switching frequency (which reduces ripple but decreases efficiency) and a higher switching frequency (which increases efficiency but may increase ripple) based on real-time conditions, thereby optimizing both parameters differently at different operating points rather than compromising both continuously.
Data Source
AI summary
A display apparatus includes a display panel configured to display an image, a driver configured to drive the display panel, and a power supply including an output circuit configured to charge or discharge power input through an input terminal thereof to output through an output terminal thereof and an output controller configured to control charging or discharging of the output circuit, for supplying power to the display panel, wherein the output controller operates in one of a first driving mode of operating with a first switching frequency and a second driving mode of operating with a second switching frequency which is higher than the first switching frequency.