Backlight Control Circuit Voltage Feedback for LCD Power Efficiency
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Solution Overview
Problem
In liquid crystal display (LCD) systems with direct backlight units, the varying forward voltages of light strings with temperature lead to inconsistent voltage values at driver IC ports, resulting in high power consumption and inefficiency.
Innovation Solution
A backlight control circuit with a driver circuit and power conversion circuit that uses current feedback signals to adjust the supply voltage for light string groups, maintaining voltage within a specific range and reducing voltage inconsistencies across channel ports.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the driver IC operates with varying forward voltages of light strings due to temperature changes, then the system can adapt to temperature variations, but the voltage values at driver IC ports become inconsistent and power consumption increases
Solution Approach 1:
The patent implements a feedback mechanism where the driver IC monitors the forward voltage of each light string and adjusts its operating parameters accordingly. This feedback loop enables the system to maintain consistent port voltages while adapting to temperature changes, thereby resolving the contradiction between temperature adaptability and power consumption efficiency
Solution Approach 2:
The patent changes operating parameters (voltage and current) of the driver IC based on detected temperature variations and light string characteristics. By dynamically adjusting these parameters, the system maintains optimal power consumption while adapting to different temperature conditions, resolving the contradiction between adaptability and energy efficiency
2Reliability
If the voltage of channel ports is kept high to ensure proper operation, then the light string group receives sufficient voltage, but power consumption of the driver IC increases
Solution Approach 1:
The patent employs dynamic voltage adjustment where the driver IC continuously adapts the voltage level at channel ports based on real-time monitoring of light string performance and temperature conditions. This dynamic approach ensures reliable operation while minimizing power consumption by avoiding consistently high voltage levels, thus resolving the contradiction between operation stability and energy efficiency
3Use of energy by moving object
If the voltage of channel ports is kept low to reduce power consumption, then power efficiency improves, but the voltage may fall below the cut-in voltage or knee voltage causing abnormal luminosity
Solution Approach 1:
The patent uses feedback control where the driver IC monitors the voltage at channel ports and adjusts it to maintain levels above the cut-in or knee voltage thresholds. This feedback mechanism ensures that power consumption is minimized while preventing voltage from dropping to levels that would cause abnormal luminosity, resolving the contradiction between energy efficiency and luminosity reliability
Data Source
AI summary
A backlight control circuit is provided, which includes a driver circuit and a power conversion circuit. The driver circuit includes a feedback output terminal and at least one channel port. The channel port is coupled to a first terminal of a light string group. The driver circuit is configured to obtain a voltage of each channel port, and enable the feedback output terminal to provide a current feedback signal based on the voltage Vch. The power conversion circuit is coupled to the feedback output terminal and includes a voltage output terminal. The voltage output terminal is configured to provide a supply voltage for a second terminal of each light string group. The power conversion circuit is configured to perform voltage conversion on an input voltage, and increase or decrease the supply voltage based on the current feedback signal.