LED Source Driver Current Compensation for Capacitive Coupling
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Solution Overview
Problem
In LED display systems using passive matrix driving mode, capacitive coupling between channels leads to unintended brightness changes in pixels, affecting the overall display effect due to the switching of driving currents.
Innovation Solution
A driving system with source drivers that include compensating circuits and controllers to adjust the driving current and state duration, using a common voltage bus and bus capacitors to minimize the impact of capacitive coupling by compensating the driving current changes when switching between driving and non-driving states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If passive matrix driving mode is used to drive LED panel, then the driving system can control pixels through row and column lines, but capacitive coupling between channels causes unintended brightness changes in pixels
Solution Approach 1:
The patent utilizes the capacitive coupling effect that was previously harmful to convert it into a beneficial compensation mechanism. By detecting the brightness change caused by capacitive coupling and using this information to adjust the driving current, the system transforms the harmful interference into a useful feedback signal for maintaining display quality.
Solution Approach 2:
The patent introduces a feedback mechanism where the brightness change detection circuit monitors the actual brightness of pixels and compares it with expected values. The driving current adjustment circuit then uses this feedback information to compensate for capacitive coupling effects by adjusting the driving current accordingly, creating a closed-loop control system.
2Illumination intensity
If driving current is output to a channel to control pixel brightness, then the pixel can display light, but other channels are affected through capacitive coupling paths
Solution Approach 1:
The patent converts the harmful capacitive coupling interference into a useful feedback signal. By detecting the brightness change caused by capacitive coupling and using this information to adjust the driving current, the system transforms the interference into a mechanism for maintaining consistent brightness across all channels.
Solution Approach 2:
The patent dynamically adjusts the driving current parameter based on the detected brightness changes. When capacitive coupling causes brightness variations, the system changes the driving current parameter to compensate for these variations, ensuring consistent pixel brightness across different channels.
3Productivity
If multiple channels are driven simultaneously, then the display can show multiple pixels, but brightness uniformity across channels deteriorates due to capacitive coupling
Solution Approach 1:
The patent implements a feedback mechanism that monitors brightness uniformity across multiple channels and adjusts driving currents accordingly. The brightness change detection circuit continuously monitors pixel brightness, and the driving current adjustment circuit modifies the current distribution to maintain uniformity, enabling simultaneous operation of multiple channels with consistent brightness.
Solution Approach 2:
The patent dynamically changes the driving current parameters for different channels based on real-time brightness detection. When capacitive coupling causes brightness variations in simultaneously driven channels, the system adjusts the current parameters individually for each channel to restore brightness uniformity across the entire display.
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 reduces brightness variations across channels, improving the LED display effect by maintaining consistent driving currents and minimizing the effects of capacitive coupling, resulting in a more uniform and stable display.
Implementation Method 1
each driving circuit among the plurality of driving circuits includes: a bus capacitor, connected between the current control line and the common voltage bus
Data Source
AI summary
A source driver and a driving system for driving an LED panel, and an LED display system are provided. The driving system includes: a plurality of source drivers, for respectively supplying driving currents to channels of different portions on the LED panel, and each source driver includes: a plurality of driving circuits, which are in one-to-one correspondence with the plurality of channels on the LED panel, and are connected to a same current control line, each driving circuit being configured to supply a driving current to a corresponding channel, wherein, the supplied driving current is associated with a voltage on the current control line which the driving circuit is connected with. When one or more driving circuits switch between a non-driving state and a driving state, the driving current being supplied by the driving circuit(s) being in the driving state in the plurality of source drivers is compensated.