Driving Circuit Reducing Power Loss in Display Devices
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Solution Overview
Problem
Current display device driving circuits experience increased power loss due to voltage drops and IR drop variations, particularly when additional thin film transistors are used to control light emitting diodes, leading to inefficiencies in power management.
Innovation Solution
A driving circuit comprising a first transistor, a capacitor, and a driving transistor, which reduces components on the current path by providing a data signal and a start signal to output a driving signal, thereby minimizing power loss and eliminating the influence of threshold voltage and IR drop variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If additional thin film transistors are connected in series on the power trace to control light emitting diode, then the control capability is improved, but the power loss increases due to voltage drop
Solution Approach 1:
The invention extracts the EM TFT from the current path of the light emitting diode, placing it only in the gate control path instead. This separation allows the EM TFT to control the driving transistor without being part of the power-consuming current path, thus maintaining control capability while eliminating unnecessary power loss from voltage drops across multiple series-connected transistors
Solution Approach 2:
The control function is segmented into two independent parts: the EM TFT handles gate control signals separately, while the driving transistor handles the actual light emitting diode current control. This segmentation allows each component to perform its function optimally without compounding voltage drops, reducing overall power loss while maintaining full control capability
2Reliability
If multiple thin film transistors are connected in series for compensation circuits, then the compensation function is improved, but the device complexity increases
Solution Approach 1:
The EM TFT is extracted from the current path and positioned solely in the gate control path, where it performs threshold voltage compensation and controls the driving transistor. This extraction maintains the necessary compensation function while reducing the number of transistors in the current path from three to two, thereby simplifying the device structure
Solution Approach 2:
The EM TFT performs multiple functions: it provides threshold voltage compensation, generates the emission control signal, and regulates the driving transistor. By consolidating these functions into a single transistor in the gate path rather than requiring multiple transistors in series in the current path, the invention maintains compensation capability while reducing device complexity
3Ease of operation
If an Emission thin film transistor is added to control the lighting time of the light emitting diode, then the duty ratio control is improved, but the power loss increases
Solution Approach 1:
The EM TFT acts as an intermediary control element in the gate path that regulates the driving transistor's operation. By controlling the gate voltage of the driving transistor rather than being in series with the light emitting diode current, it can adjust duty ratio and lighting time without directly consuming power from the light emitting diode current path, thus improving control efficiency while minimizing power loss
Data Source
AI summary
A driving circuit includes a first transistor, a capacitor, a second transistor, and a driving transistor. The first transistor is configured to provide a data signal according to a first scan signal. The capacitor is coupled to the first transistor, and the capacitor includes a first terminal and a second terminal. The second transistor is coupled to the first transistor, and the second transistor is configured to provide a start signal according to the data signal. The driving transistor is coupled to the second transistor, and the driving transistor is configured to output a driving signal according to the start signal.