OLED Driving Circuit Voltage Jumping for Splash Screen Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional OLED driving circuits can cause a splash screen phenomenon during power-up due to abnormal current generation, leading to DC-DC failure and the inability to light up the display panel.
Innovation Solution
A method and circuit for driving OLEDs that involve voltage jumping of the reference voltage, reset voltage, and data signal inputs to control the driving transistor, turning it off before outputting the EL high level and turning it back on after outputting the EL low level, using boost and buck units to manage these voltages effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the EL high level ELVDD is output before the EL low level ELVSS in the power-on process, then the driving transistor can be turned on to drive the display element, but the large current during the 10ms period causes leakage current and lifts the EL low level ELVSS, resulting in false short circuit detection and DC-DC circuit cutoff
Solution Approach 1:
The patent applies preliminary action by detecting the EL low level ELVSS voltage before outputting the EL high level ELVDD during the power-on process. The SSD circuit performs detection at a predetermined time point before the ELVDD output, identifying potential voltage lifting issues in advance and preventing false short circuit detection, thereby ensuring reliable operation while maintaining fast power-on speed
Solution Approach 2:
The patent implements feedback by continuously monitoring the EL low level ELVSS voltage through the SSD circuit. The detection mechanism provides real-time feedback on the voltage level, allowing the system to identify when the ELVSS is abnormally lifted due to leakage current, and take appropriate actions to prevent false detection and ensure stable display operation
2Device complexity
If the SSD circuit detects the EL low level ELVSS voltage immediately when outputting, then the detection timing is simple, but the 10ms delay causes abnormal display and large current generation, leading to leakage current and false short circuit detection
Solution Approach 1:
The patent applies preliminary action by performing the ELVSS voltage detection before the ELVDD output rather than immediately after. This timing adjustment prevents the detection from occurring during the period when large current and leakage current are present, eliminating the harmful detection effect while maintaining simple control logic
Solution Approach 2:
The patent converts the potentially harmful large current period into a beneficial detection window by detecting the ELVSS voltage before the ELVDD output. The timing is strategically chosen to avoid the harmful current effects while still enabling effective short circuit detection, turning what would be a problematic time period into an optimal detection opportunity
Data Source
AI summary
A method, a circuit and a display device for driving an organic light emitting diode, wherein a driving transistor (DTFT) for driving a display element is turned off by jumping one or more of a reference voltage input (Vref), a reset voltage input (Vinit) and a data signal input (Vdata) before beginning to output an EL high level (ELVDD) of a pixel compensation circuit and after beginning to output an EL low level (ELVSS), to overcome the splash screen phenomenon during power-up and direct current-direct current driving failure.