Display Panel Power Sequencing for Flicker and Short-Circuit Prevention
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Solution Overview
Problem
Complex display panel circuits, particularly in OLED panels, lead to issues such as flickering images and short circuits during power-on and power-off processes due to unstable transistor states.
Innovation Solution
A driving apparatus and method that includes specific timing sequences for providing power and control signals to the display panel circuits, ensuring stable operation by grounding power terminals and using invalid start signals during initial phases, and providing valid signals only after circuit stabilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If power signals are provided to the pixel circuit during power-on process, then the display panel can operate, but the transistors are in unstable state causing flickering images and short circuits
Solution Approach 1:
The patent applies preliminary action by providing power signals to the gate driving circuit and source driving circuit before providing them to the pixel circuit. The gate driving circuit and source driving circuit are activated in advance to stabilize their internal transistors, and only after they are stable do they receive and transmit signals to the pixel circuit. This preliminary stabilization prevents the harmful effect of unstable transistor states causing flickering and short circuits while maintaining fast power-on performance.
2Reliability
If invalid start signals are provided during initial time period, then circuit stability is improved, but the power-on process takes longer time
Solution Approach 1:
The patent segments the power-on process into distinct time periods with different signal states. During the first time period, invalid start signals are provided to prevent unstable operation. During the second time period, valid start signals are provided after circuits are stabilized. This segmentation allows the system to balance reliability during the initial phase with timely operation in the subsequent phase, minimizing overall power-on time while ensuring circuit stability.
Solution Approach 2:
The invalid start signal phase serves as a preliminary stabilization period where power signals are provided to driving circuits without activating full operation. This preliminary action allows transistors to stabilize before valid start signals are provided, reducing the need for extended stabilization time during full operation and thus minimizing total power-on time.
3Adaptability or versatility
If complex circuits are used in OLED panel, then display performance is improved, but the number of transistors increases leading to more unstable states
Solution Approach 1:
The patent applies preliminary action by stabilizing the complex driving circuits before they control the pixel circuit. The gate driving circuit and source driving circuit, which contain multiple transistors, are activated and stabilized in advance during the first time period. This preliminary stabilization ensures that even though the circuits are complex with many transistors, they are in stable states before controlling the display, thus maintaining display functionality while managing circuit complexity.
Data Source
AI summary
Embodiments of the present disclosure relate to an apparatus and method for providing power on and power off timing sequence for driving a display panel. The display panel includes a pixel circuit, a gate driving circuit, and a source driving circuit. The apparatus for driving a display panel is configured to: during a first time period, provide an invalid start signal to the gate driving circuit and/or a light-emitting control driving circuit; during a second time period, provide a first power signal and a second power signal to the pixel circuit; and during a third time period, provide a valid start signal to the gate driving circuit and/or the light-emitting control driving circuit.