Pixel Driving Circuit Reducing Transistor Count for AMOLED Displays
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Solution Overview
Problem
Conventional pixel driving circuits for AMOLED displays face challenges due to a high number of transistors required for threshold voltage compensation, leading to narrow intervals between pixels.
Innovation Solution
A pixel driving circuit with a pre-charging control unit, storage capacitor, and threshold compensation unit, where the driving transistor is directly controlled by the data signal during the threshold compensation period, reducing the number of transistors and increasing pixel spacing by optimizing the connection and control signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional pixel driving circuit with threshold compensation function is used, then the threshold voltage can be compensated, but the number of transistors increases leading to narrow intervals between pixels
Solution Approach 1:
The patent merges the pre-charging function and threshold compensation function into a single integrated circuit structure. The pre-charging control unit and threshold compensation unit share common transistors and control signals, reducing the total transistor count while maintaining both functions. Specifically, the driving transistor serves dual purposes in both pre-charging and threshold compensation operations.
Solution Approach 2:
The patent implements multi-functionality by designing control units that perform multiple operations. The pre-charging control unit not only pre-charges the storage capacitor but also participates in the threshold compensation process. The threshold compensation unit is designed to work seamlessly with the pre-charging function, allowing the same hardware to serve multiple purposes throughout different time periods.
2Reliability
If a conventional pixel driving circuit with threshold compensation function is used, then the threshold voltage can be compensated, but the number of control signals increases leading to narrow intervals between pixels
Solution Approach 1:
The patent combines multiple control functions into fewer control signals. The pre-charging control unit and threshold compensation unit are controlled by integrated control logic that reuses the same control signals for multiple purposes. This merging of control functions reduces the total number of control signals required while maintaining the ability to perform both pre-charging and threshold compensation.
Solution Approach 2:
The patent employs periodic action by dividing the operation into distinct time periods (pre-charging period, threshold compensation period, light-emitting period) where different functions are activated sequentially. During the pre-charging period, the pre-charging control unit is activated; during the threshold compensation period, the threshold compensation unit operates. This time-division multiplexing allows the same hardware to perform different functions at different times, reducing the need for simultaneous control signals.
Data Source
AI summary
The present disclosure provides a pixel driving circuit, a pixel driving method and a display apparatus. The pixel driving circuit includes a pre-charging control unit, a storage capacitor, a driving transistor and a threshold compensation unit. The pre-charging control unit charges the storage capacitor by a supply voltage during a pre-charging period; the threshold compensation unit during the threshold compensation period, together with the driving transistor and under the control of the control signal, controls the storage capacitor to be discharged until a voltage of the second electrode of the driving transistor becomes Vdata+Vth; and during a light-emitting period, control a gate-source voltage of the driving transistor to compensate for Vth, where Vth is a threshold voltage of the driving transistor, and Vdata is a voltage of the data signal.