Li-ion LED Bicycle Lamp Microcontroller Control
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Solution Overview
Problem
Battery-powered bicycle headlamps, including LED headlamps, experience a gradual diminishment of beam intensity as the battery drains, often reaching a low level before the user is aware of a potentially dangerous condition, and there is a need for power conservation and extended battery life.
Innovation Solution
A lightweight, Li-ion powered LED lamp with a microcontroller that monitors the battery charge and voltage, providing a visual warning of low power through flashing and controlling the LED operation and charging by adjusting current pulses and duty cycles, while maintaining balanced cell voltages during charging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If LED power levels are reduced to conserve power and prolong battery life, then battery duration is extended, but illumination intensity decreases
Solution Approach 1:
The patent implements periodic action by using pulse-width modulation (PWM) to deliver current pulses to the LED at varying duty cycles. This allows the LED to operate at different effective power levels through periodic switching rather than continuous operation, enabling power conservation while maintaining the ability to provide full intensity when needed. The microcontroller controls the duty cycle to balance battery life extension with illumination requirements.
2Device complexity
If a single microcontroller is used to control both LED operation and power supply charging functions, then device complexity is reduced, but control precision for multiple functions becomes more difficult
Solution Approach 1:
The patent applies universality by designing a single microcontroller to perform multiple functions: controlling LED operation at different power levels, monitoring battery charge state, managing the charging process with precise current regulation, and detecting cell voltage balance. This multi-functional approach reduces overall device complexity by eliminating separate control circuits while the microcontroller's programmable nature maintains the precision needed for charging control through software-implemented algorithms.
3Quantity of substance
If Li-ion battery cells are operated to maximize capacity, then energy storage is increased, but cell voltage imbalance and overcharging risks increase
Solution Approach 1:
The patent implements feedback control by continuously monitoring the voltage of each Li-ion battery cell through the microcontroller. When charging, the system uses this feedback to detect voltage imbalance between cells and adjusts the charging current accordingly. The feedback mechanism also monitors overall battery charge state to prevent overcharging by reducing or stopping current when voltage thresholds are reached, thereby maintaining safety while maximizing energy storage capacity.
Solution Approach 2:
The patent applies partial action by implementing a staged charging approach where the charging current is reduced or modified when cells approach full charge or when voltage imbalance is detected. Rather than maintaining constant maximum charging current, the system partially reduces current under specific conditions (voltage thresholds, imbalance detection) to prevent overcharging and maintain cell balance, thus prioritizing reliability over maximum charging speed.
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 system maintains a nearly constant illumination level, provides an automatic low-battery warning, and prolongs battery life by optimizing power usage and charging, ensuring safe and reliable operation.
Implementation Method 1
a light source comprising at least one light-emitting diode
Implementation Method 2
an electrochemical source of direct current
Data Source
AI summary
An LED lamp adapted for use as a bicycle light includes a lamp/switch module and a power supply/control module. The control includes a microcontroller that performs both light operating functions and battery charging control functions. A low battery warning is provided as a non-repeating, short sequence of flashes of the lamp.