Display DC-DC Converter Mode Switching for Low-Luminance Efficiency
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Solution Overview
Problem
As the size and luminance range of display panels increase, the DC-DC converter in display devices experiences reduced conversion efficiency and increased power loss due to large internal resistors and repeated switching, leading to unnecessary power consumption and heat generation, especially at low luminance levels.
Innovation Solution
A DC-DC converter is designed with a normal mode and a power saving mode, utilizing a first and second converter that operate in different driving manners based on inductor currents and mode control signals, with reduced transistor turn-on times and discontinuous periods to minimize power loss, and a mode selector to manage these modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the display panel size and luminance range are increased, then the driving current range is expanded, but the conversion efficiency of the DC-DC converter is reduced
Solution Approach 1:
The patent implements dynamic switching between normal mode and power saving mode based on the display luminance level. The mode selector dynamically adjusts the operating mode of the DC-DC converter to match the actual driving conditions, optimizing conversion efficiency across different luminance ranges while maintaining adaptability to various display requirements
Solution Approach 2:
The patent changes the operating parameters of the DC-DC converter by implementing different driving manners (first, second, and third driving manners) with distinct transistor turn-on times and switching frequencies. This allows the converter to optimize its performance parameters according to the operating mode, improving conversion efficiency when the display operates at low luminance levels
2Power
If the DC-DC converter operates with repeated switching, then the voltage conversion function is maintained, but power loss and heat generation increase
Solution Approach 1:
The patent implements periodic action by introducing discontinuous periods where transistor switching is reduced or suspended. In power saving mode, the converter operates with longer discontinuous periods, reducing the frequency of switching operations while maintaining voltage conversion capability through energy storage in inductors, thereby reducing power loss and heat generation
Solution Approach 2:
The patent ensures continuity of useful action by maintaining voltage output to the display panel even during discontinuous switching periods. The inductors store energy during active switching phases and release it during discontinuous periods, ensuring continuous power delivery to the display while reducing overall switching frequency and associated losses
3Device complexity
If the internal resistor is made relatively large, then the converter structure is simplified, but unnecessary power consumption increases
Solution Approach 1:
The patent dynamically adjusts the effective resistance in the converter circuit by switching between different transistor configurations and operating modes. In power saving mode, the system optimizes the resistance characteristics to minimize power consumption while maintaining necessary voltage conversion, preventing unnecessary energy waste even when structural simplification is considered
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 power consumption and heat generation by optimizing the driving frequencies and voltages in both normal and power saving modes, enhancing conversion efficiency and allowing flexible control of luminance in the power saving mode.
Implementation Method 1
a first converter which outputs a first power voltage in a normal mode or in a power saving mode based on a first inductor current generated by alternately turning on a plurality of transistors therein
Data Source
AI summary
A direct current-to-direct current (“DC-DC”) converter includes: a first converter which outputs a first power voltage in a normal mode or a power saving mode based on a inductor current generated therein, where the first converter operates in a first driving manner in the normal mode, and operates in a second driving manner in the power saving mode; a second converter which outputs a second power voltage based on a inductor current generated therein, where the second converter operates in a third driving manner in the power saving mode, and a magnitude of the second power voltage in the power saving mode is different from that in the normal mode; and a mode selector which supplies a mode control signal to the first and second converters, where the first and second converters are driven in the normal mode or the power saving mode based on the mode control signal.