Display Panel Driving Circuit Pre-Charge Resistor Reduction
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Solution Overview
Problem
Existing display panel driving circuits require a large number of resistors to produce 64 different voltage levels, increasing the circuit area and power consumption, which affects driving capability and efficiency.
Innovation Solution
A driving circuit that uses a pre-charge power supply to charge a capacitor in advance, reducing the number of resistors needed and minimizing power consumption by utilizing a pre-charge switch, buffer circuit, and series-connected resistive devices to generate driving signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If 64 resistors are used to produce 64 different voltage levels, then the reference voltage generation capability is improved, but the circuit area is increased
Solution Approach 1:
The patent applies preliminary action by pre-charging the compensation capacitor to a reference voltage before the normal charging operation. This pre-charging step is controlled by a pre-charge switch that is activated during a specific time period (first time period) before the data signal charging phase. By pre-charging the capacitor to the correct voltage level in advance, the circuit eliminates the need for 64 separate resistors to generate all possible voltage levels, as the capacitor is already positioned at the correct reference voltage to begin charging from. This significantly reduces the circuit area while maintaining the ability to generate all 64 different voltage levels through the combined action of the pre-charge path and the data signal charging path.
2Measurement precision
If 64 resistors are used to produce reference voltages, then the voltage level precision is improved, but the power consumption is increased
Solution Approach 1:
The patent eliminates continuous power consumption by resistors through preliminary action. Instead of having 64 resistors continuously dissipating power to maintain 64 different voltage levels, the system pre-charges the compensation capacitor to the correct reference voltage during a first time period when the pre-charge switch is activated. During the second time period when data is displayed, only the necessary charging current from the data signal flows through the liquid crystal cell. This preliminary pre-charging action ensures precise voltage levels are achieved without the continuous power waste of maintaining all 64 voltage levels through resistive dividers throughout the entire operating cycle.
Solution Approach 2:
The patent implements periodic action by dividing the operating cycle into distinct time periods with different functions. The pre-charge switch operates periodically during the first time period to charge the compensation capacitor to the reference voltage, then remains off during the second time period when the display data is charged. This periodic activation of the pre-charge path ensures that power is consumed only when necessary for initialization, while the display operation uses minimal power. The liquid crystal cell is driven in a periodic manner alternating between pre-charge phase and data display phase, significantly reducing overall power consumption compared to continuous resistor-based voltage generation.
3Area of stationary object
If resistors with larger resistance are used to reduce circuit area, then the area is reduced, but the driving capability is affected
Solution Approach 1:
The patent resolves the contradiction between using large resistance values for area reduction and maintaining driving capability through preliminary action. The pre-charge switch provides a dedicated low-resistance charging path during the initialization phase, ensuring that the compensation capacitor can be quickly charged to the reference voltage without being limited by large resistance values. This preliminary low-resistance charging path establishes the correct voltage level rapidly, after which the display operation proceeds with the data signal charging. The liquid crystal cell receives sufficient driving current during both phases, maintaining full driving capability while achieving compact circuit area through the selective use of low resistance only when needed for initialization.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution shortens the driving time and conserves power by avoiding resistor-based power consumption, thereby reducing the display panel's area and improving efficiency.
Implementation Method 1
A driving circuit uses a pre-charge power supply to charge a capacitor of a display panel in advance
Data Source
AI summary
The present invention relates to a driving circuit for a display panel, which comprises a pre-charge power supply, a pre-charge switch, a buffer circuit, and a plurality of resistive devices. The pre-charge switch is coupled between the pre-charge power supply and a capacitor of the display panel. The buffer circuit is used for buffering a data signal and producing a buffer signal. The plurality of resistive devices is connected in series and coupled to the buffer circuit, and produces a plurality of driving signals therebetween according to the buffer signal. The driving circuit first closes the pre-charge switch to make the pre-charge power supply charge the capacitor. Then, one of the plurality of driving signals charges the capacitor. Thereby, the driving time can be shortened, and power of the display can be saved by avoiding power consumption on resistors.