DC-DC Converter Adaptive Voltage Control for OLED Efficiency
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Solution Overview
Problem
Conventional DC-DC converters used in organic light emitting displays experience efficiency deterioration as the input voltage from a battery decreases, leading to reduced operational time due to the inefficiencies of booster and inverter circuits, especially when generating higher output voltages from lower input voltages.
Innovation Solution
Incorporating a voltage detecting unit within the DC-DC converter to dynamically control the output voltage of the inverter circuit, adjusting the voltage of the second power supply ELVSS based on the sensed input voltage, thereby maintaining efficiency and ensuring the organic light emitting diodes operate within a saturation region for optimal image display.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a booster circuit and inverter circuit are used to generate ELVDD and ELVSS, then the organic light emitting display device can operate with proper power supply voltages, but the operational efficiency deteriorates as the difference between input voltage and output voltage increases
Solution Approach 1:
The patent applies dynamics by making the power supply voltage adaptive rather than fixed. The ELVDD and ELVSS voltages are dynamically adjusted based on the current input voltage level from the battery. As the input voltage decreases, the output voltages are proportionally reduced to maintain optimal efficiency. This dynamic adaptation allows the display device to operate efficiently across varying battery voltage conditions, preventing the efficiency deterioration that occurs with fixed voltage circuits when input voltage drops.
2Loss of energy
If the input voltage from battery decreases, then the booster circuit and inverter circuit stop operations due to efficiency decrease, but this shortens the time of use of the battery
Solution Approach 1:
The patent applies parameter changes by modifying the operating voltage parameters adaptively. Instead of maintaining fixed output voltages, the system changes the voltage parameters (ELVDD and ELVSS) in response to input voltage variations. When the battery voltage decreases, the output voltages are adjusted to appropriate lower levels, allowing the booster and inverter circuits to continue operating efficiently rather than shutting down. This parameter adaptation extends the usable battery life by maintaining efficient operation across a wider voltage range.
3Stability of the object's composition
If fixed voltage power supplies ELVDD and ELVSS are used, then the pixel circuit operates stably, but the DC-DC converter efficiency decreases when converting from lower input voltages
Solution Approach 1:
The patent applies feedback by implementing a control mechanism that monitors the input voltage from the battery and uses this information to adjust the output voltages ELVDD and ELVSS. The system continuously adapts the power supply voltages based on the current input conditions, ensuring that the DC-DC converter operates at optimal efficiency points. This feedback-controlled voltage adjustment maintains stable operation of the pixel circuit while preventing efficiency loss in the voltage conversion process.
Data Source
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AI summary
A DC-DC converter with improved efficiency achieved by controlling a voltage of a power supply transmitted to an organic light emitting diode in accordance with a voltage of a battery, and an organic light emitting display device using the same. A DC-DC converter according to one embodiment includes a voltage detecting unit for detecting a voltage of a battery, a booster circuit for receiving and boosting the input voltage to generate and output a first power, and an inverter circuit for receiving and inverting the input voltage to generate and output a second power, where the voltage of the second power is controlled and output corresponding to the input voltage detected by the voltage detecting unit.