Display Panel Pre-Charge Control for Consistent LED On-Time
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Solution Overview
Problem
The influence of the equivalent on-resistance of scanning switches on the on-time of light emitting diodes in display panels, particularly in LED panels, is not effectively addressed in existing dynamic driving modes, leading to variations in display time due to the charging of parasitic capacitors.
Innovation Solution
A pre-charge control method and device that dynamically adjusts the target pre-charge voltage based on the number of data channels to be turned on, compensating for the voltage on the equivalent on-resistance of scanning switches to maintain consistent on-time for light emitting diodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If more data channels are turned on at the same time, then the display coverage is improved, but the voltage on the equivalent on-resistance of scanning switches increases, affecting the on-time of light emitting diodes
Solution Approach 1:
The patent applies preliminary action by pre-charging the parasitic capacitors of light emitting diodes before the actual turn-on period. The pre-charge control unit dynamically adjusts the pre-charge voltage based on the number of data channels to be turned on, preparing the capacitors in advance to compensate for the voltage drop that will occur when multiple channels are activated simultaneously. This ensures that the actual turn-on time remains consistent even when display coverage increases.
Solution Approach 2:
The patent implements dynamics by making the pre-charge voltage dynamic rather than fixed. The pre-charge control unit dynamically adjusts the pre-charge voltage level according to the number of data channels that need to be turned on during each scanning line's turn-on period. When more channels are activated, the pre-charge voltage is increased to compensate for the greater voltage drop across the scanning switch's on-resistance, thereby maintaining consistent on-time across varying display coverage conditions.
2Device complexity
If a fixed pre-charge voltage is used, then the control complexity is reduced, but the on-time of light emitting diodes varies when different numbers of data channels are turned on
Solution Approach 1:
The patent implements dynamics by making the pre-charge voltage dynamic rather than fixed. The pre-charge control unit dynamically adjusts the pre-charge voltage level according to the number of data channels that need to be turned on during each scanning line's turn-on period. When more channels are activated, the pre-charge voltage is increased to compensate for the greater voltage drop across the scanning switch's on-resistance, thereby maintaining consistent on-time across varying display coverage conditions.
Solution Approach 2:
The patent applies feedback by using the number of data channels to be turned on as feedback information to adjust the pre-charge voltage. The pre-charge control unit receives information about how many data channels will be activated and uses this feedback to determine the appropriate pre-charge voltage level, creating a closed-loop control system that automatically compensates for variations in display coverage requirements.
3Speed
If the parasitic capacitor is pre-charged to a higher voltage, then the turn-on speed of light emitting diodes is improved, but the voltage margin for compensation of on-resistance drop is reduced
Solution Approach 1:
The patent implements dynamics by making the pre-charge voltage dynamic rather than fixed. The pre-charge control unit dynamically adjusts the pre-charge voltage level according to the number of data channels that need to be turned on during each scanning line's turn-on period. When more channels are activated, the pre-charge voltage is increased to compensate for the greater voltage drop across the scanning switch's on-resistance, thereby maintaining consistent on-time across varying display coverage conditions.
Solution Approach 2:
The patent applies parameter changes by varying the pre-charge voltage parameter based on the operating conditions. Instead of using a fixed pre-charge voltage, the system changes the pre-charge voltage parameter dynamically according to the number of active data channels, allowing optimal balance between turn-on speed and compensation capability under different display coverage scenarios.
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
The method ensures consistent and efficient turn-on times for light emitting diodes by pre-charging them to a target voltage, reducing the impact of equivalent on-resistance variations, thereby maintaining display performance.
Implementation Method 1
the parasitic capacitor is usually pre-charged to slightly lower than the turn-on voltage of the light emitting diode before the turn-on period thereof
Implementation Method 2
a current flowing through the equivalent on-resistance will be greater, and accordingly, a voltage on the equivalent on-resistance will be higher
Data Source
AI summary
A pre-charge control method and device for a display panel, a display system and a driving method thereof are provided. The pre-charge control method for the display panel includes: obtaining a number of data channels on the display panel to be turned on during a turn-on period of a scanning line; determining a target pre-charge voltage for pre-charging the data channels to be turned on based on the number of the data channels to be turned on; and pre-charging the data channels to be turned on based on the target pre-charge voltage before turning on the data channels to be turned on.