LED Driver Voltage Regulation via Current-Based Feedback Bus
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Solution Overview
Problem
Existing solutions for regulating voltage in LED lighting systems with multiple integrated circuits are inefficient and prone to electromagnetic compatibility (EMC) issues and potential offsets, as they rely on diode-based feedback signals and complex wiring for voltage control.
Innovation Solution
A voltage-controlled voltage regulator system using voltage-controlled current sources and a control bus to synchronize PWM modulation across integrated circuits, ensuring efficient voltage regulation with reduced susceptibility to EMC and offsets by using transistors and differential amplifiers to adjust the control bus voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If diode-based feedback signals are used for voltage regulation in LED lighting systems, then voltage control can be achieved, but the system becomes susceptible to electromagnetic compatibility (EMC) issues and potential offsets
Solution Approach 1:
The patent replaces the diode-based voltage feedback mechanism with a current-based feedback mechanism. Instead of using diodes to generate feedback signals proportional to voltage, the invention uses current sources that generate feedback signals proportional to current, thereby eliminating the susceptibility to EMC issues and offsets associated with diode-based voltage sensing.
Solution Approach 2:
The patent changes the fundamental parameter used for feedback from voltage to current. By measuring current instead of voltage and using this current measurement to control the power stage, the system achieves more reliable voltage regulation without the EMC susceptibility inherent in voltage-based feedback approaches.
2Adaptability or versatility
If multiple integrated circuits are used to supply LED groups, then lighting flexibility and control capability are improved, but the complexity of synchronizing PWM modulation and regulating voltage increases
Solution Approach 1:
The patent merges the PWM control functions of multiple integrated circuits into a unified system. All ICs share a common PWM control signal and a common current-based feedback mechanism, allowing them to operate in unison without requiring complex inter-IC communication or synchronization protocols.
Solution Approach 2:
The patent creates a universal control architecture where the same current-based feedback mechanism and PWM control approach can be applied regardless of the number of integrated circuits used. This multi-functional approach allows the system to scale from one to many ICs without increasing synchronization complexity.
3Device complexity
If a common voltage source supplies multiple LED groups, then system simplicity is maintained, but electrical power drops and waste heat increase due to voltage regulation losses
Solution Approach 1:
The patent implements a current-based feedback control mechanism that continuously monitors the current through each LED group and adjusts the power stage to maintain optimal voltage levels. This feedback approach minimizes voltage regulation losses and reduces waste heat generation while maintaining system simplicity.
Solution Approach 2:
The patent introduces dynamic voltage regulation that adapts to the specific requirements of each LED group. Rather than using a fixed voltage source, the system dynamically adjusts voltage levels based on real-time current measurements, thereby minimizing power drops and energy losses while keeping the overall architecture simple.
Data Source
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AI summary
The invention relates to a method for regulating the output voltage (V0) at the output (Vout) of a voltage regulator (VREG) and to an associated apparatus. The method is used to supply an illumination apparatus having a plurality of, but at least two, integrated circuits (IC1, IC2), each having at least one LED group (LED1a, LED1b, LED2), by means of a respective current source (LED DRV) associated with this LED group. The method comprises the first step of generating a supply voltage (V0) by means of the voltage regulator (VREG), the second step of setting an LED group current (ILED1a, ILED1b, ILED2) through the LED groups (LED1a, LED1b, LED2) by means of a respective one of these current sources (LED DRV), the third step of capturing the voltage drops across these current sources (LED DRV) as a respective voltage drop value, the fourth step of selecting a respective voltage drop value of each integrated circuit (IC1, IC2) as a characterizing voltage drop value of this integrated circuit (IC1, IC2), the fifth step of generating a regulation value signal at a node (K1, K2) of this respective integrated circuit (IC1, IC2) according to this characterizing voltage drop value, the sixth step of reducing the magnitude of a regulation voltage (VR) if the magnitude of the regulation voltage (VR) is greater than the magnitude of the regulation value signal at the node (K1, K2) of this respective integrated circuit (IC1, IC2), and the last step of regulating the output voltage (V0) on the basis of the regulation voltage (VR) and/or a regulation bus voltage (VRB) derived from the regulation voltage (VR).