Cascaded LTPO Driving Circuit for IGZO Voltage Stabilization
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Solution Overview
Problem
Conventional Low Temperature Polycrystalline Oxide (LTPO) techniques face challenges in achieving sufficient voltage levels for Indium Gallium Zinc Oxide (IGZO) due to short charging times, especially in high-frequency applications, leading to inadequate voltage levels in display areas.
Innovation Solution
A driving circuit with cascaded units, including forward/backward scan control modules, control node modules, global control modules, and output modules, is designed to manage voltage levels and output signals, ensuring a higher voltage level for gate driving signals to IGZO TFTs, thereby increasing current and addressing the voltage level issue.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional LTPO technique is used with short charging time, then high frequency display capability is achieved, but the charged voltage level of IGZO is insufficient
Solution Approach 1:
The patent introduces a preliminary charging phase before the normal scanning operation. A preliminary charging signal is applied to the IGZO TFTs in advance to ensure they reach sufficient voltage levels before active display operation begins, resolving the insufficient charging issue while maintaining high-frequency capability
Solution Approach 2:
The patent implements periodic charging cycles interspersed with display scanning cycles. The driving circuit alternates between charging IGZO TFTs to full voltage levels and then scanning the display, ensuring adequate voltage accumulation even at high frequencies where continuous charging is not feasible
2Power
If higher voltage level is applied to gate driving signal, then current increases and charging capability improves, but power consumption increases
Solution Approach 1:
The patent applies different voltage levels to different regions and time periods. High voltage is applied only to IGZO TFTs during charging phases when needed, while LTPS TFTs operate at normal voltage levels. This localized, temporal application of high voltage increases current where necessary without proportionally increasing overall power consumption
Solution Approach 2:
The patent uses excessive voltage temporarily during charging phases to ensure complete charging of IGZO TFTs, then returns to normal operating voltage during display scanning. This partial application of excessive voltage ensures reliable charging while minimizing the duration and overall impact on power consumption
Data Source
AI summary
A driving circuit and a display panel are disclosed. The driving circuit includes a plurality of cascaded driving units. The driving unit includes a forward/backward scan control module, a first control node controlling module, a second control node controlling module, a global control module, a regulating module, a first output module configured to output a stage signal, and a second output module configured to output a gate driving signal. A voltage level of the gate driving signal is higher than a voltage level of the stage signal.