LED String Emergency Lighting with Segmented Groups
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Solution Overview
Problem
Existing emergency lighting systems for solid state apparatuses are inefficient in power usage during power outages, as they often require high-capacity batteries to maintain full lumen output, increasing costs and complexity, and struggle to maintain consistent color rendering index (CRI) in emergency modes.
Innovation Solution
The emergency lighting device employs a configuration of multiple groups of solid state emitters, where normal and emergency operation currents are managed to adjust light color and intensity, using a series connection and shunt circuitry to achieve a target white color with high CRI during normal operation and reduced power usage in emergency modes, allowing for flexible driver specifications and reduced LED count.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If high-capacity batteries are used to maintain full lumen output during power outages, then illumination intensity is improved, but device complexity and cost increase
Solution Approach 1:
The LED array is divided into multiple independently controllable groups that can be selectively activated. During emergency operation, only a subset of LED groups is powered to reduce battery demand while maintaining sufficient illumination for egress requirements.
Solution Approach 2:
The system provides partial illumination by activating only necessary portions of the LED array during emergencies. This partial action approach meets code requirements for emergency lighting without requiring full lumen output, thereby reducing battery capacity needs.
2Reliability
If multiple solid state emitters are used to maintain high CRI, then color rendering is improved, but power consumption increases
Solution Approach 1:
Solid state emitters are organized into multiple groups with different color characteristics. During normal operation, all groups are activated to provide high CRI white light. During emergencies, selected groups are activated based on battery status to maintain acceptable color rendering while reducing power consumption.
Solution Approach 2:
The system dynamically adjusts the operational parameters of solid state emitter groups based on power availability. By changing which groups are active and at what current levels, the system maintains high CRI when possible while adapting to reduced power conditions during emergencies.
3Device complexity
If series connection of LED groups is used, then device complexity is reduced, but current control flexibility is limited
Solution Approach 1:
The circuit configuration dynamically switches between series and parallel connections based on operational mode. During normal operation, LEDs are connected in series for simplified control. During emergencies, the circuit reconfigures to provide flexible current control to selected LED groups, enabling adaptive power management.
Solution Approach 2:
The system uses partial activation of LED groups in series configuration during emergencies. By controlling which groups are active rather than requiring complex individual control of all LEDs, the system achieves flexible power management while maintaining relatively simple circuitry.
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 configuration enables efficient power usage during emergencies, maintains high CRI for accurate color rendition, and allows for interchangeable emergency LED drivers, reducing battery capacity and cost while ensuring compliance with code requirements.
Implementation Method 1
a first group of solid state emitters configured to emit light of a first color
Implementation Method 2
solid state emitters configured to emit light
Data Source
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AI summary
Emergency lighting devices and methods are disclosed. An emergency lighting device includes a first group of solid state emitters configured to emit light of a first color. The emergency lighting device also includes a second group connected in series to the first group and configured to emit a second color. The groups are configured to receive a normal operation current from an LED driver at the input end of the first group and output the normal operation current at the output end of the second group. In an emergency, the first group receives an emergency operation current from an emergency LED driver at an emergency input and outputs the emergency operation current at an emergency output located.