Current Limiting Circuit for Illumination Light Communication
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Solution Overview
Problem
Existing illumination light communication systems using constant-current feedback power supplies experience reception errors due to current overshoot during 100% modulation, which affects the reliability of light communication.
Innovation Solution
Incorporating a current limiting circuit in series with the light source and switch to regulate the current flow, preventing it from exceeding a set value, thereby mitigating overshoot and ensuring stable communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If 100% modulation is used to maximize communication efficiency, then productivity is improved, but current overshoot occurs causing reception errors and reducing reliability
Solution Approach 1:
The current limiting circuit performs preliminary action by pre-establishing a maximum current threshold before modulation begins. When the drive signal attempts to exceed this threshold during 100% modulation, the circuit proactively clamps the current, preventing overshoot before it can cause reception errors. This allows the system to maintain high communication efficiency while ensuring signal reliability.
2Stability of the object's composition
If constant-current feedback power supply is used to maintain stable illumination, then illumination stability is improved, but current overshoot during switching occurs causing communication errors
Solution Approach 1:
The current limiting circuit acts as an intermediary between the constant-current feedback power supply and the light-emitting element. While the feedback system maintains stable illumination by regulating average current, the current limiting circuit mediates transient overshoots during switching by clamping peak currents. This dual-layer control allows both illumination stability and communication reliability to coexist.
3Productivity
If higher modulation depth is used to increase data transmission rate, then productivity is improved, but signal distortion increases causing reception errors
Solution Approach 1:
The current limiting circuit applies preliminary anti-action by pre-establishing a maximum current clamp level that prevents signal distortion before it occurs. During high-depth modulation, the circuit actively counteracts tendency toward overshoot by maintaining current within safe boundaries, thereby enabling high data transmission rates without sacrificing signal accuracy or causing reception errors.
Data Source
AI summary
An illumination light communication apparatus includes: a light source which emits illumination light; a power supply circuit for supplying constant current to the light source; a switch which is connected in series to the light source, and intermittently interrupts current which flows through the light source; a signal generating circuit which generates a binary communication signal which controls on and off of the switch to modulate the illumination light; and a current limiting circuit which is connected in series to the light source and the switch, and limits the current which flows through the light source to prevent the current from exceeding a current set value which is variable.