Solid State Light Source Driver Circuit Power Limiting
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Solution Overview
Problem
Conventional driver circuits for solid state light sources are costly due to stringent component performance and accuracy requirements, and they aim to provide a constant power supply which is not necessary for all applications, especially those with fluctuating power demands.
Innovation Solution
A driver circuit that receives AC input and supplies power to a light emitting element while limiting it to an upper cut-off value between maximum efficiency and operation power, storing excess power for later use during low input periods, allowing the light emitting element to operate efficiently with fluctuating power and reducing component complexity and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional driver circuit with power factor correcting converter and capacitors is used to provide constant power, then the light emitting element can operate with stable power supply, but the device complexity and manufacturing cost increase significantly
Solution Approach 1:
The patent extracts and removes the complex power factor correcting converter and large capacitors from the driver circuit. Instead, it uses a simple series capacitor and resistor network that directly processes the AC input voltage without requiring additional conversion stages, thereby eliminating the complex components while maintaining functional operation.
Solution Approach 2:
The series capacitor and resistor network performs multiple functions simultaneously: it limits peak current, provides power factor correction, and enables direct AC-to-LED operation without requiring separate stages for rectification, filtering, and regulation. This multi-functional approach replaces the multi-stage conventional circuit with a single integrated solution.
2Power
If a power factor correcting converter with large capacitors is used, then constant power can be delivered to the light emitting element, but the manufacturing cost increases due to stringent component requirements
Solution Approach 1:
The patent employs inexpensive, readily available components such as standard series capacitors and resistors that can be easily manufactured and replaced. These components have relaxed tolerance requirements compared to conventional circuits, making them cheaper and easier to manufacture at scale without requiring precision components.
Solution Approach 2:
The circuit changes the operating parameters by allowing the LED current to follow the AC waveform directly rather than being rectified and filtered to DC. This parameter change enables the use of simpler components with different electrical characteristics, reducing the need for high-performance, costly components while maintaining acceptable operation.
3Reliability
If the driver circuit limits power to an upper cut-off value between maximum efficiency power and maximum operation power, then the light emitting element is protected against excess power, but the light output fluctuates with AC input variations
Solution Approach 1:
The circuit intentionally allows partial power delivery variations by not fully smoothing the AC waveform. The series capacitor limits peak current to protective levels while permitting the natural AC fluctuations to pass through, accepting partial light output variation as a trade-off for using simpler protection circuitry without large filtering capacitors.
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
This solution enables efficient operation of light emitting elements with power fluctuations, reducing overheating risks and allowing for cost-effective production, particularly suitable for applications like infrared radiation generation where power fluctuations are not critical, while maintaining light output and extending component lifespan.
Implementation Method 1
the driver circuit is arranged for storing power from the AC input during a period in which the power from the AC input exceeds the upper cut-off value
Data Source
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AI summary
The invention relates to solid state light source, a use of a driver circuit for driving a light emitting element (150) of a solid state light source, a method for driving a light emitting element (150) of a solid state light source and a corresponding computer program. The invention provides that for a large amount of an AC period the light emitting element (150) is directly supplied with the AC input directly forwarded by the driver circuit, wherein nevertheless it is prevented that power exceeding a desired level reaches the light emitting element (150).The invention is aimed at a realization with simplified components and/or reduced costs in comparison to known techniques.