Dynamic OLED Voltage Adjustment for Power Reduction
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Solution Overview
Problem
Conventional organic light emitting display devices face high power consumption due to a fixed voltage supply for driving transistors, which is inefficient as the turn-on voltage of OLEDs increases over time, especially in small products.
Innovation Solution
A power supply system dynamically adjusts the voltage provided to the OLED cathode based on the detected drain voltage of the driving transistor, using a DC-DC Converter to maintain the driving transistor in the saturation region, thereby avoiding extra power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed voltage Vss1 with high magnitude is provided to maintain driving transistor operation, then the driving transistor can operate in the saturation region even when OLED turn-on voltage increases, but extra power consumption occurs
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed voltage supply to a dynamic voltage adjustment mechanism. The power supply system continuously monitors the drain voltage of the driving transistor and adjusts Vss1 in real-time to maintain the saturation condition (Vds ≥ Vsg - |Vth|) only when necessary, rather than maintaining a constantly high voltage level.
Solution Approach 2:
The patent implements feedback by using the detected drain voltage of the driving transistor as a control signal for adjusting the voltage Vss1. The power supply system receives feedback about the actual operating conditions and modifies the supply voltage accordingly, creating a closed-loop control system that optimizes power consumption while ensuring reliable operation.
2Duration of action of stationary object
If a fixed voltage Vss1 is provided considering maximum OLED turn-on voltage increment, then driving transistor saturation is maintained over time, but power consumption increases due to unnecessarily high voltage magnitude
Solution Approach 1:
The system dynamically adapts the voltage level based on the actual OLED turn-on voltage at any given time, rather than using a fixed high voltage designed for worst-case scenarios. This allows the system to operate efficiently during the early life of the OLED when turn-on voltage is lower, while still maintaining proper operation throughout the OLED's lifetime.
Solution Approach 2:
The patent changes the voltage parameter Vss1 from a fixed value to a variable that adjusts based on OLED aging characteristics. The power supply system modifies the voltage magnitude according to the detected drain voltage, which reflects the actual OLED turn-on voltage, thereby optimizing the balance between operational reliability and power consumption over the device's lifetime.
Data Source
AI summary
A display unit is provided. The display unit includes a light-emitting diode, a driving transistor, and a power supply system. The light-emitting diode comprises a cathode and an anode. The driving transistor comprises a source, a drain, and a gate, wherein the gate receives a first voltage, the drain is coupled to a second voltage via the light-emitting diode and the gate receives a third voltage. The power supply system is coupled to the drain of the driving transistor, providing the second voltage in response to the voltage of the drain of the driving transistor.