LED Driver Feed-Forward Control for DC Link Ripple Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing LED drivers face challenges in accurately compensating for internal DC link voltage ripple, which can lead to output ripple issues and increased production costs due to cumbersome FEFO gain adjustments.
Innovation Solution
The proposed LED driver incorporates a self-adjusting feed-forward control system that uses narrow-band filters and a gain adjustment unit to dynamically adjust the FEFO gain based on observed output ripple, ensuring optimal compensation without preadjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual FEFO gain adjustment is performed during production, then compensation accuracy may be improved, but production cost increases and manufacturing complexity increases
Solution Approach 1:
The system automatically adjusts the FEFO gain parameter by monitoring the control error and detecting its frequency component, eliminating the need for manual adjustment during production. The controller autonomously optimizes the feed-forward control based on observed ripple characteristics.
Solution Approach 2:
The FEFO gain is transformed from a static fixed value set during production into a dynamic parameter that automatically adapts to operating conditions. The system continuously monitors control error frequency components and adjusts the gain accordingly to maintain optimal compensation.
2Measurement precision
If manual FEFO gain adjustment is performed during production, then compensation accuracy may be improved, but device complexity increases
Solution Approach 1:
The system uses feedback from the control error signal to automatically adjust the FEFO gain. By detecting the frequency component of the control error and comparing it with the known ripple frequency, the system self-tunes the feed-forward compensation without external intervention.
Solution Approach 2:
The controller autonomously performs the entire FEFO gain adjustment process by monitoring its own control error and automatically adapting the feed-forward parameter, eliminating complex manual adjustment procedures.
3Device complexity
If fixed FEFO gain is used, then device complexity is reduced, but compensation accuracy deteriorates due to component tolerances and lifetime issues
Solution Approach 1:
The FEFO gain transitions from a fixed static value to a dynamic parameter that automatically adapts to changing operating conditions and component characteristics over time, maintaining optimal compensation without manual intervention.
Solution Approach 2:
The system automatically changes the FEFO gain parameter based on detected control error frequency components, allowing the control characteristic to adapt to component tolerances and aging effects without manual adjustment.
4Object-generated harmful factors
If overcompensation is applied, then output ripple may be reduced, but output ripple increases due to incorrect adjustment
Solution Approach 1:
The system uses feedback from the control error signal to automatically adjust the FEFO gain, preventing overcompensation by continuously monitoring the actual compensation effect and adapting the gain accordingly.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Disclosed is a driver (1) for at least one LED (5). The driver (1) comprises a switched-mode power supply, SMPS, (27, 102, 103) configured to supply the at least one LED (5); a closed-loop control (2) for regulating a controlled variable (28) supplied to the at least one LED (5) in accordance with a reference variable (21); and a feed-forward control (3) for adjusting a control variable (24) of the closed-loop control (2) in dependence of a frequency component of a control error (22) of the closed-loop control (2) and a frequency component (29) of a DC link/bus voltage (113) of the SMPS (27, 102, 103). This avoids an adjustment of a feed-forward (FEFO) gain at a design stage, which is cumbersome and prone to inaccuracies.