Load-Aware LED Backlight Compensation for EMI Reduction
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Solution Overview
Problem
Conventional LED-based backlighting systems face challenges with power management, particularly in large displays, as they often generate electromagnetic interference and audible noise due to phase-shifted PWM dimming, which affects power efficiency and perceived quality.
Innovation Solution
A load-aware power management system that includes a controller with a compensation feedback loop, using a load-aware controller to regulate the power source based on load conditions, enabling phase-shifted PWM dimming without interference or noise, by adjusting the voltage applied to the backlight circuitry while maintaining constant current supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If phase-shifted PWM dimming is implemented in LED-based backlighting systems, then power efficiency is improved, but electromagnetic interference and audible noise are generated
Solution Approach 1:
The patent implements a compensation feedback loop that monitors the power source output and adjusts it dynamically. The controller receives feedback about the actual power delivery conditions and modifies the PWM dimming signal accordingly, compensating for the harmful effects of electromagnetic interference and audible noise while maintaining power efficiency improvements.
Solution Approach 2:
The patent changes the parameters of the power delivery system by implementing load-aware compensation that adjusts voltage and current parameters dynamically. The system modifies PWM duty cycle and frequency parameters based on detected load conditions, allowing it to maintain efficient power delivery while eliminating the harmful interference and noise effects.
2Device complexity
If conventional PWM dimming is used without load-aware compensation, then device complexity is reduced, but power efficiency deteriorates due to inability to adapt to load conditions
Solution Approach 1:
The compensation system is designed to be self-regulating, where the controller automatically detects load conditions and adjusts power delivery parameters without external intervention. The feedback loop continuously monitors system state and makes real-time adjustments, enabling the system to serve itself and maintain optimal power efficiency without requiring complex external control infrastructure.
3Use of energy by moving object
If voltage is reduced to improve power efficiency, then power consumption decreases, but current supply stability may be compromised
Solution Approach 1:
The patent dynamically changes power delivery parameters by reducing voltage while simultaneously adjusting current parameters to maintain stability. The load-aware controller monitors both voltage and current conditions, making coordinated parameter adjustments that reduce overall power consumption while ensuring current supply remains stable through compensatory current regulation.
Data Source
AI summary
System(s) and method(s) are provided for power management in an electronic display via compensation of a power source of a light-emitting-diode (LED) backlighting system. A compensation feedback loop includes a load-aware controller that receives the bad condition from a dimming controller and supplies a control signal to the power source. An efficiency regulator functionally connected the backlight circuitry closes the compensation, feedback loop and provides an input signal to the load-aware controller. The dimming controller implements phase-shifted pulse-modulation dimming, which based on duty cycle can establish a dimming equilibrium with two load conditions. The load aware controller includes a set of compensation blocks arranged in parallel, with a single compensation block connected to the input signal and that provides the control signal. A selector component in the load aware controller determines a compensation block to be connected to the compensation feedback loop based on the received load condition.