Liquid Crystal Display Driving Circuit Ripple Reduction
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Solution Overview
Problem
Existing driving circuits for liquid crystal displays experience large ripple waves in output voltage due to discontinuous conduction mode, especially when input voltage loading is low or varies significantly, leading to inefficient power management.
Innovation Solution
A driving circuit design incorporating a voltage stabilizing triode and non-adjustable capacitors, along with two distinct driving signals - a simulation voltage and a digital voltage - to stabilize current and prevent simultaneous entry into discontinuous conduction mode, thereby reducing ripple waves in the output voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the power supply management chip enters DCM mode due to low or varying loading, then the driving signal can operate with higher efficiency, but the ripple wave of the output voltage becomes very large
Solution Approach 1:
The patent combines two driving signals (first and second driving signals) into a single drive system for the liquid crystal display. By merging the functions of separate drive circuits into one integrated driving circuit with shared capacitors and diodes, the system achieves better coordination between signals, preventing simultaneous DCM mode entry while maintaining driving efficiency and reducing output voltage ripple.
Solution Approach 2:
The patent introduces a voltage stabilizing triode as an intermediary component between the driving signals and the output stage. This triode acts as a mediator that stabilizes the voltage and reduces ripple waves by controlling the current flow, thereby resolving the contradiction between maintaining efficient DCM operation and minimizing harmful voltage fluctuations.
2Device complexity
If non-adjustable capacitors are used in the driving circuit, then the device complexity is reduced, but the ability to optimize performance under varying load conditions is limited
Solution Approach 1:
The patent divides the capacitance function into multiple separate non-adjustable capacitors (first, second, third, and fourth capacitors) positioned at different stages of the driving circuit. Each capacitor serves a specific function in its local circuit section, allowing the overall system to handle varying load conditions effectively while maintaining simple individual components and reduced device complexity.
Data Source
AI summary
The present invention discloses a driving circuit and a liquid crystal display device. An anode of a first diode is employed for inputting a voltage, and a cathode of the first diode is coupled to an anode of a second diode, and a cathode of the second diode is coupled to an anode of a third diode, and a cathode of the third diode is coupled to an anode of a fourth diode, and a cathode of the fourth diode is employed for outputting the voltage.