Flashlight PWM Controller for Continuous Intensity Adjustment
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Solution Overview
Problem
Conventional portable lighting devices, such as flashlights, lack flexibility in achieving desired light illumination intensities, typically offering only a limited number of predetermined settings without the ability to effectively select other intensities.
Innovation Solution
A portable lighting device with light control circuitry that includes a user-activated switch and a controller, which processes signals to incrementally adjust the light beam's intensity by modifying the duty cycle of a pulse width modulated signal, allowing continuous adjustment of light illumination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple switch positions are employed to select different light illumination intensities, then multiple predetermined intensity levels are provided, but the flexibility to select other intensities is limited
Solution Approach 1:
The patent employs pulse width modulation (PWM) to vary the duty cycle of the PWM signal, which directly changes the effective power delivered to the LED. By adjusting the duty cycle parameter from 0% to 100%, continuous intensity control is achieved without requiring multiple discrete switch positions or multiple LED arrays, thus resolving the contradiction between adaptability and device complexity
Solution Approach 2:
The invention introduces a dynamic control mechanism where a single switch position can dynamically adjust the light intensity through PWM duty cycle variation. This dynamic approach replaces the static multiple switch positions design, allowing the system to adapt to different intensity requirements while maintaining a simple switching structure
2Device complexity
If a single light source is used, then device simplicity is maintained, but the ability to provide multiple light illumination intensities is limited
Solution Approach 1:
The patent introduces PWM control circuitry as an intermediary between the single light source and the power supply. This intermediary mechanism modulates the power delivery to the LED through duty cycle adjustment, enabling a single light source to provide multiple intensity levels without requiring multiple physical light sources, thus maintaining device simplicity while achieving intensity versatility
Solution Approach 2:
The invention uses periodic PWM signals to control the LED intensity. By varying the duty cycle of the periodic PWM waveform, different average power levels are delivered to the LED, creating multiple effective intensity levels from a single light source. This periodic modulation approach enables intensity control without adding physical complexity
Data Source
AI summary
A lighting device embodied as a flashlight is provided that includes a handheld housing and a light source provided on the housing for generating a light beam. The light device also includes a battery power source for providing power to the light source. The lighting device further includes light control circuitry for turning the light source on and off and controlling intensity of the light beam. The light control circuitry includes a user actuatable switch and a controller for controlling intensity of the generated light beam. The controller processes user activation of the switch and adjusts the intensity of the light beam as a function of the activation of the switch such that the light intensity may be increased or decreased.