Flip-Flop Circuit for Adjustable Duty Ratio Clock Signals
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Solution Overview
Problem
The existing Pulse Amplitude Modulation (PAM) and Pulse Width Modulation (PWM) driving modes for display technologies face issues such as high power consumption, heat generation, complexity, and inability to achieve low grey scale display, which hinder the development of advanced technologies like high PPI and narrow borders.
Innovation Solution
A flip-flop circuit with an input sub-circuit, AND gate, control sub-circuit, duty ratio adjustment sub-circuit, and reset sub-circuit, which allows for adjustable duty ratio clock signals to control the brightness of a light emitting device, reducing power consumption and heat generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If PAM driving mode is used, then the display can achieve grey scale, but power consumption is high and heat is generated
Solution Approach 1:
The patent employs PWM (Pulse Width Modulation) driving mode which uses periodic pulse signals with varying duty ratios to control the grey scale of display pixels. Instead of continuous analog voltage control (PAM), the system uses periodic switching of digital signals, where the duty ratio (ratio of high level time to total period) determines the perceived brightness. This periodic digital switching reduces power consumption and heat generation compared to continuous analog control.
2Use of energy by moving object
If PWM driving mode is introduced to solve PAM problems, then power consumption is reduced, but circuit complexity increases
Solution Approach 1:
The patent merges the PWM driving function directly into the pixel circuit structure by integrating a flip-flop circuit that generates duty-ratio-adjustable clock signals within the pixel itself. This integration combines the driving control logic with the display element, eliminating the need for separate complex external driving circuits while maintaining the power-saving benefits of PWM mode.
Solution Approach 2:
The pixel circuit is designed with multi-functionality, where the same circuit structure performs both data storage and PWM signal generation. The flip-flop circuit within each pixel can store display data and simultaneously generate the required clock signals with adjustable duty ratios, reducing the need for additional dedicated driving circuitry and simplifying the overall system architecture.
3Illumination intensity
If full-screen driving mode with fixed duty ratio is used, then the display can show grey scale, but power consumption remains high
Solution Approach 1:
The patent introduces dynamic duty ratio adjustment capability where each pixel's flip-flop circuit can independently adjust its clock signal duty ratio based on the required grey level. Instead of using a fixed duty ratio for all pixels (full-screen driving mode), the system dynamically varies the duty ratio for each pixel according to its specific brightness requirement, thereby reducing overall power consumption while maintaining accurate grey scale display.
Data Source
AI summary
A flip-flop circuit and a pixel driving circuit are provided. In the flip-flop circuit, the AND gate is configured to control a clock signal output from the output terminal based on input signals of the first and second input terminals; the input sub-circuit is configured to write the second power supply voltage into the first and/or second input terminal in response to an input control signal to control the output terminal to output the first or second power supply voltage; the control sub-circuit is configured to control a potential at a first node through the second power supply voltage in response to a data voltage control signal; the duty ratio adjustment sub-circuit is configured to control the output terminal to output the first power supply voltage in response to a potential at the first node.