DC-DC Converter Voltage Adjustment for OLED Power and Noise
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Solution Overview
Problem
In organic light emitting displays, the fixed voltage of the cathode electrode leads to increased power consumption and noise generation due to rapid changes in driving voltage, as images are not always represented with maximum gray levels.
Innovation Solution
A DC-DC converter is used to generate adjustable first and second voltages, with a pulse width modulation controller and voltage adjuster to control switching times and voltage levels, reducing rapid voltage changes and noise by adjusting the second voltage based on luminance and display size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the voltage of the cathode electrode is fixed to the voltage corresponding to when the saturation current is greatest, then the OLED can achieve maximum saturation current, but power consumption increases and noise is generated due to rapid voltage changes
Solution Approach 1:
The patent applies dynamics by making the cathode electrode voltage adjustable rather than fixed. The voltage adjuster dynamically changes the cathode electrode voltage according to the required saturation current level, allowing the system to adapt to different operating conditions. This resolves the contradiction by enabling the voltage to be optimized for each specific current requirement rather than being permanently set at the maximum current level, thereby reducing power consumption when maximum current is not needed.
Solution Approach 2:
The patent implements parameter changes by varying the cathode electrode voltage based on the required saturation current. The voltage adjuster modifies the voltage parameter to match the actual display needs, whether full-screen or partial-screen operation. This allows the system to operate efficiently at different voltage levels corresponding to different current requirements, eliminating the waste of maintaining maximum voltage when lower current levels suffice.
2Use of energy by moving object
If the driving voltage is rapidly changed to adjust for different saturation currents, then power consumption is reduced, but noise is generated
Solution Approach 1:
The patent applies preliminary action by pre-adjusting the cathode electrode voltage before changing the saturation current. The voltage adjuster proactively sets the appropriate voltage level in advance, preventing rapid voltage transitions that would generate noise. This ensures that when the saturation current changes, the voltage is already at the optimal level, avoiding sudden adjustments and the associated noise during operation.
3Device complexity
If the voltage of the cathode electrode is fixed, then the device structure is simple, but power consumption increases when maximum saturation current is not required
Solution Approach 1:
The patent introduces dynamic voltage adjustment capability with minimal structural complexity. The voltage adjuster is designed as a straightforward component that receives control signals and adjusts the cathode electrode voltage accordingly. This simple dynamic structure enables power optimization without significantly complicating the device, allowing the voltage to adapt to different operating modes while maintaining an elegant and manageable design.
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
This approach reduces power consumption and minimizes noise by adjusting the second voltage level in organic light emitting displays, ensuring efficient power use and improved image representation.
Implementation Method 1
a first voltage generator for generating the first voltage by switching an input voltage and accumulating energy in a first coil
Implementation Method 2
a second voltage generator for generating the second voltage by switching an input voltage and accumulating energy in a second coil
Data Source
AI summary
A DC-DC converter and an organic light emitting display using the DC-DC converter are provided. The DC-DC converter can generate a first voltage and a second voltage lower than the first voltage, where the DC-DC converter includes a first voltage generator for generating the first voltage by switching an input voltage and accumulating energy in a first coil, a second voltage generator for generating the second voltage by switching an input voltage and accumulating energy in a second coil, a pulse width modulation (PWM) controller for controlling switching times of the first and second voltage generators in accordance with a control signal, and a voltage adjuster for generating the control signal to vary a voltage level of the second voltage and control a time of change of the second voltage.