Pulsed High-Power LED Flash Circuit for Compact Photography Lighting
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Solution Overview
Problem
Existing flashes, predominantly HID lamps, suffer from short lifespan, low light efficacy, and complex circuitry due to high voltage requirements, and using high-power LEDs results in increased size and cost without adequate brightness for high-speed photography.
Innovation Solution
A high-power LED circuit with pulsed operation, incorporating an LED light source group, energy storage capacitor, NMOS transistor, freewheeling diode, and common mode choke, controlled by a PWM signal and optionally an MCU, to provide adjustable flash energy and longevity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If HID lamps are used for flashes, then high brightness is achieved, but lifespan is short and light efficacy is low
Solution Approach 1:
The patent changes the fundamental operating parameters by switching from HID lamp technology to LED technology, which operates at lower voltages and currents. This parameter change enables significantly extended lifespan while maintaining adequate brightness through the LED's high luminous efficacy, directly resolving the contradiction between brightness and lifespan
2Illumination intensity
If HID lamps are used for flashes, then high brightness is achieved, but light efficacy is low and energy consumption is high
Solution Approach 1:
The patent employs parameter changes by adopting LED technology which operates at lower voltage and current levels compared to HID lamps. The LED's inherent high luminous efficacy converts electrical energy more efficiently into light, dramatically reducing energy consumption while maintaining the required brightness levels for photography applications
3Illumination intensity
If higher power LED is chosen to improve brightness, then brightness is improved, but size and cost of light equipment double
Solution Approach 1:
The patent applies periodic action through pulsed LED operation controlled by PWM signals. By delivering high current in short pulses rather than continuous operation, the circuit achieves high peak brightness for flash photography while the average power consumption and thermal load remain low, preventing the need for oversized heat sinks and power supplies that would increase device size and cost
4Duration of action of moving object
If ordinary LED light source is used for patch light, then longevity is improved, but brightness is insufficient for high-speed photography
Solution Approach 1:
The patent resolves this contradiction by implementing periodic high-current pulses through the LED using PWM control. The LED operates at low current during normal conditions to maintain longevity, but delivers high current in brief pulses during flash operation to achieve the necessary peak brightness for high-speed photography, thus satisfying both requirements simultaneously
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
Enhances flash longevity, reduces energy consumption, and achieves ultra-small volume with high light efficiency, increasing flash frequency and reducing equipment cost, while maintaining photographic effectiveness.
Implementation Method 1
energy storage capacitor, with one terminal electrically connected to the above-mentioned LED light source group
Implementation Method 2
LED light source group
Implementation Method 3
utilizing LED light source as a flash for patching light
Data Source
AI summary
The invention discloses high-power LED circuit with pulsed operation for flashlights, comprising: LED group; energy storage capacitor, with one terminal electrically connected to the LED group, and the other grounded; NMOS transistor, with gate electrically connected to PWM to control signal, and source grounded; freewheeling diode, with input electrically connected to the drain of NMOS transistor, and output electrically connected to the LED group input; common mode choke, with one terminal electrically connected to the LED group output, and the other electrically connected to freewheeling diode input and the drain of NMOS transistor; mainly achieves the replacement of traditional HID (High Intensity Discharge Lamp) with pulse-resistant large-current LED in flashlight, significantly improve flashlight life; and compared to conventional LED flash, achieves ultra-compact LED flash with 50-100 times the power of larger LED flash photographic effect, with high portability significantly reducing photography equipment cost.