Dual Feedback LED Power Circuit for Precise Output Control
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Solution Overview
Problem
Conventional power circuits for LED loads, particularly those adhering to UL1310 Class 2 standards, face limitations in control accuracy for output power due to reliance on peak switching current limiting, often triggering protection prematurely when output power exceeds rated levels, leading to inefficient power management.
Innovation Solution
The implementation of a power circuit with two independent feedback modules and a control circuit that detect output voltage and current, forming separate feedback loops to ensure output power remains below a predetermined threshold, even in the event of a single component fault, thereby enhancing control accuracy and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If peak switching current limiting is used to control output power, then the power protection point can be triggered when output power exceeds rated power, but the control accuracy of the output power is relatively low and protection may be triggered prematurely
Solution Approach 1:
The patent implements dual feedback loops that continuously monitor output voltage and current, providing real-time feedback to the control circuit. This enables precise control of the power converter's output power by adjusting the switching duty cycle based on actual output conditions, thereby improving both control accuracy and preventing premature protection triggering while maintaining reliable power limitation.
2Device complexity
If a single feedback loop is used in the power circuit, then the circuit structure is simple, but a single component fault can cause the feedback loop to fail and lose control of the output power
Solution Approach 1:
The patent divides the feedback system into two independent feedback loops, each with its own feedback module and control path. This segmentation ensures that a component failure in one loop does not affect the other, maintaining output power control reliability even under fault conditions while keeping each individual loop structure relatively simple.
Solution Approach 2:
The patent prepares compensatory measures in advance by implementing redundant feedback loops. When a component fault occurs in one feedback loop, the other loop is already in place to take over and maintain control, providing beforehand cushioning against potential failures and ensuring continuous reliable operation.
3Power
If the output power limitation is implemented through limiting the peak switching current, then the protection can be triggered when output power exceeds rated power, but the control accuracy is low and protection triggers prematurely when output power exceeds rated power by a great amount
Solution Approach 1:
The patent replaces peak current limiting with continuous feedback-based power control. The feedback modules monitor output voltage and current, and the control circuit adjusts the power converter's switching parameters in real-time to maintain output power below the predetermined threshold, achieving both power limitation and high control accuracy without premature protection triggering.
Data Source
AI summary
The present application discloses a power circuit applied in a LED load. The power circuit includes: a power converter configured to convert an input voltage into a DC output voltage; a first feedback module configured to detect the output voltage and an output current of the power converter, and to output a first feedback signal; a second feedback module configured to detect the output voltage and the output current of the power converter, and to output a second feedback signal, the second feedback module and the first feedback module being independent to each other; and a control circuit configured to output a control circuit according to the first feedback signal or the second feedback signal to control the power converter via the control signal so as to make the output power of the power converter smaller than a predetermined power threshold.