Dynamic Bias Current Adjustment in LCD Source Drivers
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Solution Overview
Problem
Conventional liquid crystal display (LCD) devices face challenges in reducing power consumption, particularly when transitioning to lower frame rates, as the constant bias current output by source drivers does not proportionally decrease with frame rate, leading to inefficient power-saving modes and longer charging times.
Innovation Solution
The LCD device dynamically adjusts bias current output and enables/disables power-saving functions like charge recycling based on frame rate, allowing for reduced power consumption by altering the charging time of liquid crystal capacitors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If the source driver outputs constant bias current, then the driving ability is maintained, but power consumption cannot be reduced proportionally to frame rate
Solution Approach 1:
The source driver dynamically adjusts bias current output based on frame rate requirements. In normal mode (60Hz), the source driver outputs higher bias current to maintain driving ability. In power-saving mode (30Hz), the source driver reduces bias current to lower power consumption, accepting reduced driving ability as a trade-off.
Solution Approach 2:
The invention changes the bias current parameter according to operating conditions. By detecting frame rate and switching between normal mode and power-saving mode, the system adjusts the bias current parameter to match actual display needs, reducing unnecessary power consumption while maintaining adequate driving ability for the given frame rate.
2Use of energy by stationary object
If charge recycling technique is used, then output current is saved, but transmission time increases
Solution Approach 1:
The system dynamically selects between charge recycling mode and normal mode based on frame rate requirements. When operating at lower frame rates (30Hz), the system enables charge recycling to reduce power consumption. When operating at higher frame rates (60Hz), the system uses normal mode to maintain faster transmission speed, avoiding the time penalty of charge recycling.
3Use of energy by stationary object
If frame rate is reduced for power-saving mode, then power consumption should decrease, but constant bias current prevents expected power reduction
Solution Approach 1:
The timing controller detects the frame rate and provides feedback to the source driver. Based on this feedback, the source driver automatically adjusts bias current output. This feedback mechanism enables the system to reduce power consumption by matching bias current to actual frame rate requirements, while the control complexity is managed through automated detection and adjustment.
Data Source
AI summary
A liquid crystal display device of reducing power consumption includes a liquid crystal panel having a plurality of liquid crystal capacitors for displaying an image, an input interface for generating a scan control signal, an oscillator for generating a predetermined frequency, a control unit electrically coupled to the oscillator for outputting a current control signal when a frequency of the scan control signal is lower than the predetermined frequency, and a driving circuit electrically coupled to the controller for generating a first bias current to charge the plurality of liquid crystal capacitors of the liquid crystal panel.