AMOLED Pixel Driving Circuit Speeds Charging via Current Division
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Solution Overview
Problem
The existing AMOLED pixel structures have a slow charging speed due to a small charging current, which is not suitable for high-resolution and high-refreshing-frequency displays.
Innovation Solution
An AMOLED pixel unit driving circuit that includes a switching unit, a storage capacitor, a driving TFT, and a current dividing unit, which allows for a large charging current to be divided and efficiently charged, enabling a relatively large current to flow through the OLED, thus expediting the charging speed of the storage capacitor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a small charging current is used to charge the storage capacitor, then the OLED operating current is maintained within the operating range, but the charging speed becomes slow
Solution Approach 1:
The patent introduces a current dividing unit that segments the charging current into two separate paths: one path provides current to charge the storage capacitor, and the other path provides current to the OLED. This segmentation allows the total charging current to be much larger than before, while the OLED receives only the appropriate operating current, thus resolving the contradiction between fast charging speed and proper OLED current range.
2Speed
If a large charging current is applied directly to the storage capacitor, then the charging speed increases, but the OLED receives excessive current beyond its operating range
Solution Approach 1:
The current dividing unit acts as an intermediary between the charging current source and the OLED. It receives the large charging current and divides it into appropriate portions, ensuring that the OLED receives current within its safe operating range while allowing the overall charging process to use much larger currents for faster charging.
3Duration of action of stationary object
If the storage capacitor has large capacitance to ensure proper operation, then the charging time becomes substantially long, but reducing capacitance affects display performance
Solution Approach 1:
The patent changes the parameter of charging current from small to large by introducing the current dividing unit. This parameter change allows the storage capacitor to be charged much faster, reducing charging time from substantially long to acceptable levels, while maintaining the capacitor's large capacitance value needed for proper display performance.
Data Source
AI summary
The present disclosure discloses an AMOLED pixel unit driving circuit and method, an AMOLED pixel unit and a display apparatus, the AMOLED pixel unit driving circuit includes: a switching unit with a first input terminal connected to a current source for supplying a charging current and a second input terminal connected to an OLED; a storage capacitor with a first terminal connected to an output terminal of the switching unit and a second terminal connected to a low level; a driving TFT with a gate electrode connected to the first terminal of the storage capacitor and a source electrode connected to the low level; and a current dividing unit with a first terminal connected to the low level. The embodiments of the present disclosure enable a relatively large scale to exist between the charging current Idata and the current loled flowing through the OLED.