Pulsed High-Power LED Circuit for Compact Flashlight Photography

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Solution Overview

Problem

Existing flashes, particularly HID lamps, suffer from short lifespan, low light efficacy, and complex circuitry due to high voltage requirements, and using higher power LEDs for brighter flashes increases size and cost, making them impractical for photography.

Innovation Solution

A high-power LED circuit with pulsed operation, comprising an LED light source group, energy storage capacitor, NMOS transistor, freewheeling diode, and common mode choke, controlled by a PWM signal, allowing adjustable flash energy through adjustable duty cycles and current amplitudes.

Engineering Contradictions & Design Principles

VSEngineering 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

Engineering Contradiction:

ImprovebrightnessVSAvoidlifespan

Core Design Contradiction:

Illumination intensityVSReliability

Solution Approach 1:

The patent replaces expensive, short-lived HID lamps with inexpensive, long-lived LED light sources. The LED circuit can be disposed of after battery depletion without significant cost or environmental impact, while achieving comparable or superior performance with extended operational life.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Illumination intensity

If HID lamps are used for flashes, then high brightness is achieved, but circuitry becomes complex due to high voltage requirements

Engineering Contradiction:

ImprovebrightnessVSAvoidcircuitry complexity

Core Design Contradiction:

Illumination intensityVSDevice complexity

Solution Approach 1:

The patent replaces complex high-voltage electrical systems with simple low-voltage LED circuitry. The mechanical/electrical complexity of HID ballasts and high-voltage switching is substituted with straightforward LED driver circuits operating at safe voltages, dramatically simplifying the overall system.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Illumination intensity

If higher power LED is chosen to improve brightness, then light output increases, but size and cost of equipment double

Engineering Contradiction:

ImprovebrightnessVSAvoidequipment size

Core Design Contradiction:

Illumination intensityVSVolume of moving object

Solution Approach 1:

The patent employs pulsed LED operation with high current bursts synchronized to camera shutter speeds. By delivering intense light only during the brief exposure window rather than continuous illumination, the system achieves high brightness output from smaller, lower-power LEDs, avoiding the need for oversized equipment.

Inventive Principle:

Principle #19Periodic action

4Illumination intensity

If higher power LED is chosen to improve brightness, then light output increases, but cost of equipment doubles

Engineering Contradiction:

ImprovebrightnessVSAvoidequipment cost

Core Design Contradiction:

Illumination intensityVSEase of manufacture

Solution Approach 1:

Inventive Principle:

Principle #19Periodic action

5Speed

If ordinary LED light source is used with higher camera shutter speed, then camera exposure increases, but photos become darker until all black

Engineering Contradiction:

Improveshutter speedVSAvoidphoto brightness

Core Design Contradiction:

SpeedVSIllumination intensity

Solution Approach 1:

The patent synchronizes intense LED light pulses with camera shutter activation. By concentrating all light output during the brief exposure window rather than distributing it over a longer period, the system maintains high shutter speeds while ensuring sufficient light reaches the sensor, preventing underexposed black photos.

Inventive Principle:

Principle #19Periodic action

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 portability and cost-effectiveness, providing photographic effects comparable to larger LEDs while extending battery life and frequency.

Implementation Method 1

an energy storage capacitor (EC1), with one terminal electrically connected to the LED light source group

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 2

an LED light source group

Methodology Applied

Scientific EffectLight Emitting Diode: Light Emitting Diode

Implementation Method 3

utilizing LED light source as a flash for patching light

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentEP4648555A1High-power LED circuit with pulsed operation for flashlights

Publication Date: 2025.11.12 SHANGHAI CALER ELECTRONICS CO LTD

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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.