Homogeneous Transistor Emission Driver for OLED Speed
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Solution Overview
Problem
Conventional emission drivers using CMOS transistors are slow in operational speed and require an additional inversion input signal for proper operation, which limits their performance in organic light emitting diode (OLED) display devices.
Innovation Solution
An emission driving unit is implemented using only N-type or P-type transistors, controlled by a first and second clock signal, which includes an input signal generating circuit, an inverter circuit, and an output switching circuit to generate and invert the emission signals, eliminating the need for an additional inversion signal and improving operational speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If CMOS transistors are used in the emission driver, then the driver can operate with standard complementary logic, but the operational speed becomes slow and additional inversion input signals are required
Solution Approach 1:
The emission driver is redesigned to use exclusively N-type transistors or exclusively P-type transistors, eliminating the need for complementary CMOS structures. This homogeneous transistor approach simplifies the circuit architecture, removes the requirement for additional inversion input signals, and improves operational speed by utilizing the faster switching characteristics of single-type transistors in the emission driving context
2Ease of operation
If CMOS transistors are used in the emission driver, then the driver can provide stable operation, but an additional inversion input signal is required which increases signal complexity
Solution Approach 1:
The invention extracts and eliminates the requirement for additional inversion input signals by redesigning the emission driver circuit to function with a single input signal. The homogeneous transistor structure (all N-type or all P-type) inherently provides the necessary signal inversion through its switching characteristics, removing the need for separate inversion signal paths and simplifying the overall signal interface
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
In one aspect, an emission driving unit (100) and an organic light emitting diode (OLED) display having the same are disclosed. The emission driving unit (100) includes an input signal generating circuit (110) that receives a FLM signal according to a first clock signal (CLK1), receives a second clock signal (CLK2) according to the FLM signal, and outputs a sequential input signal (NEXT_IN). The emission driving unit (100) also includes an inverter circuit (130) that receives the FLM signal according to the first clock signal (CLK1), and that inverts the FLM signal to generate an inverter output signal (IVT_OUT). The emission driving unit (100) also includes an output switching circuit (150) that outputs a first voltage (VGH) having a logic high level or a second voltage (VGL) having a logic low level as an emission signal (OUT) in response to the inverter output signal (IVT_OUT). The input signal generating circuit (110), the inverter circuit (130), and the output switching circuit (150) are implemented by transistors of the same kind.