LED Drive Circuit Voltage Adjustment for Luminance Stability
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Solution Overview
Problem
Conventional LED drive circuits face challenges in maintaining stable luminance due to variations in forward bias (Vf) over time and temperature, leading to non-uniform luminance in multi-LED setups, and struggle to accurately detect and compensate for abnormal bulbs in large LED lamp sets.
Innovation Solution
A drive circuit that connects multiple LED strings in parallel, featuring a power converter, detection circuit, and report circuit to monitor and adjust the driving voltage in real-time, ensuring a constant voltage drop between the driving voltage and forward bias, thereby maintaining stable luminance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If multiple LED strings are connected in parallel to increase luminance output, then the total luminance increases, but the forward bias variations cause non-uniform luminance distribution across different LED strings
Solution Approach 1:
The patent implements dynamic voltage adjustment by continuously monitoring the forward bias of each LED string through detection circuits and automatically compensating through control circuits. This dynamic adaptation ensures that each LED string maintains consistent luminance output despite variations in forward bias characteristics, resolving the non-uniformity issue while preserving high total luminance output
Solution Approach 2:
The patent employs feedback mechanisms where detection circuits measure the actual forward bias voltage of each LED string, compare it with reference values, and feed this information back to control circuits. The control circuits then adjust the driving voltage accordingly to maintain uniform luminance across all LED strings, effectively eliminating the non-uniformity problem caused by forward bias variations
2Measurement precision
If conventional detection methods are used to identify abnormal LED bulbs, then individual bulb detection is possible, but the process is time-consuming and labor-intensive for large LED lamp sets
Solution Approach 1:
The patent merges multiple detection functions into a single integrated detection circuit that can simultaneously monitor all LED strings connected in parallel. By combining the detection capabilities across all strings, the system achieves comprehensive coverage of the entire LED lamp set in one operation, dramatically reducing detection time while maintaining high precision through automated abnormality identification
Solution Approach 2:
The detection circuit is designed with universal functionality to handle multiple LED strings simultaneously through parallel connection. The same detection and control mechanisms can be applied across different LED strings with varying numbers of LEDs, providing a scalable solution that maintains detection precision while minimizing time loss regardless of the total number of bulbs in the lamp set
3Device complexity
If the driving voltage is kept constant to simplify power supply control, then the power supply system is simple, but the luminance becomes unstable due to forward bias variations over time and temperature
Solution Approach 1:
The patent implements a self-regulating system where the detection circuits automatically monitor forward bias variations and the control circuits autonomously adjust the driving voltage without external intervention. This self-service mechanism maintains stable luminance output despite changes in forward bias over time or temperature, achieving luminance stability while keeping the power supply control system relatively simple through automated operation
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution ensures stable luminance across LED strings by dynamically adjusting the driving voltage based on real-time string voltage measurements, effectively addressing the issues of non-uniformity and forward bias variations.
Implementation Method 1
a power converter, which is connected with the power and converts into a driving voltage provided to the LED strings
Implementation Method 2
a detection circuit, which is electrically coupled to the LED strings and has at least a reference voltage, and respectively detects a string voltage of the LED strings
Implementation Method 3
a plurality of LEDs connected in series into a plurality of LED strings, and the LED strings are electrically connected in parallel
Implementation Method 4
Light emitting diodes (LEDs) are widely used in daily life
Data Source
AI summary
A drive circuit for light emitting diode (LED) is provided, which is used to drive a plurality of LEDs to emit light. The LEDs are connected in series into a plurality of LED strings. The drive circuit includes a power converter, a detection circuit, and a report circuit. The power converter provides a driving voltage to the LED strings, and the detection circuit detects a string voltage of each LED string, and compares the string voltage with a default reference voltage, so as to determine whether the string voltage is different from the reference voltage (which indicates that the LED string is operated under a non-default state), and sends a detection signal to the report circuit. The report circuit receives the detection signal and outputs the control signal to the power converter, such that the power converter adjusts the driving voltage according to the control signal.