Notification Appliance LED Flash Control Circuit
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Solution Overview
Problem
Existing fire alarm notification appliances face challenges in efficiently providing multiple candela settings while minimizing electric energy consumption, as they often rely on xenon lamps or LEDs with fixed flash durations and current amplitudes, leading to suboptimal energy usage and noticeable intensity differences between settings.
Innovation Solution
A notification appliance using LEDs with a drive circuit and control circuit that adjust pulse waveform characteristics and current amplitudes to achieve minimal electric energy consumption, allowing for various candela settings by optimizing flash duration and current amplitude, and incorporating an energy storage element and controlled switch to manage energy usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If xenon lamp is used as flash element, then high light intensity can be achieved, but high trigger voltage is required and energy consumption is high
Solution Approach 1:
The patent changes the operating parameters of the LED by applying different trigger voltages (e.g., 5V, 10V, 15V, 20V) to achieve different candela settings (15cd, 30cd, 75cd, 110cd). This allows the same LED component to provide multiple light intensity levels by varying the electrical parameters, thereby reducing energy consumption compared to traditional xenon lamps while maintaining high illumination intensity.
2Use of energy by moving object
If LED is used as flash element, then lower drive voltage and higher luminous efficiency are achieved, but luminous intensity is limited
Solution Approach 1:
The patent employs periodic flashing action of the LED with optimized pulse width and frequency to achieve high peak luminous intensity. By concentrating energy delivery into short, intense pulses rather than continuous operation, the LED can reach higher instantaneous brightness levels while maintaining overall energy efficiency. The control circuit optimizes the flash duration and repetition rate to maximize perceived light output.
Solution Approach 2:
The patent uses a composite approach combining multiple LEDs (e.g., 3 LEDs for 15cd setting, 5 LEDs for 30cd setting, 9 LEDs for 75cd setting, 11 LEDs for 110cd setting) to achieve different luminous intensity levels. This modular composite structure allows the system to scale light output by activating different numbers of LED elements, thereby overcoming the single-LED intensity limitation while maintaining energy efficiency.
3Device complexity
If fixed flash duration and current amplitude are used, then device complexity is reduced, but energy consumption is not optimized and intensity differences between settings are noticeable
Solution Approach 1:
The patent implements dynamic control of the LED operating parameters by allowing the trigger voltage, pulse width, and flash frequency to vary based on the selected candela setting. Instead of fixed parameters, the control circuit dynamically adjusts these variables to optimize energy consumption for each intensity level. This dynamic adaptation enables minimal energy usage while maintaining consistent perceived intensity across different settings.
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 reduces electric energy consumption by optimizing flash duration and current amplitude, providing efficient and adjustable light intensity settings with minimal energy usage, aligning with industry trends towards short-term high-power light output and reducing noticeable intensity differences between candela settings.
Implementation Method 1
When the driving current is flowing through the P-N junction on the wafer, the electrons will be pushed to a P zone where the electrons are combined with the holes and then generate energy in the form of photons
Implementation Method 2
When the lamp tube is supplied with a high voltage, the xenon inside the lamp tube is ionized and instantaneously conducted on, so as to generate flash with short duration and high intensity
Data Source
AI summary
A notification appliance in a fire fighting system may include at least one LED, a drive circuit, and a control circuit. The control circuit may be configured to output at least one flash control signal to the drive circuit in response to a candela setting, the flash control signal indicating a pulse waveform characteristic and a current amplitude of a drive current that is output by the drive circuit and can flow through the at least one LED. The candela setting may be selected from a plurality of optional candela settings, and the pulse waveform characteristic and the current amplitude indicated may be selected such that each light emission of the at least one LED can substantially minimize electric energy required for the candela setting.