Galvanic Isolation in Solid-State Light Source Power Circuits
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Solution Overview
Problem
Conventional lighting systems, such as incandescent and fluorescent lamps, are inefficient and not well-suited for control by AC phase-cut dimmers, while solid-state lighting systems require safer low-voltage power but struggle to operate effectively with higher AC voltages.
Innovation Solution
A solid-state light source system with a power input, rectifier, and switching mode power supply, where the secondary side is electrically isolated from the primary side, allowing for galvanic isolation and control of the light emitter using a monitoring circuit and control signal, enabling operation with higher AC voltages while ensuring user safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If solid-state lighting systems use higher AC voltages for power input, then power delivery capability is improved, but user safety deteriorates due to electrical hazard
Solution Approach 1:
The patent divides the power supply system into two electrically isolated segments: a primary side that interfaces with high-voltage AC power input, and a secondary side that provides low-voltage power to LED emitters. This segmentation through galvanic isolation allows the system to accept high-voltage input for adequate power delivery while ensuring user safety on the low-voltage output side.
Solution Approach 2:
The patent introduces a galvanically isolated switching mode power supply as an intermediary device between the high-voltage AC input and low-voltage LED output. This intermediary transforms and isolates the electrical energy, enabling safe operation with higher AC voltages while maintaining low-voltage safety on the emitter side.
2Adaptability or versatility
If solid-state lighting systems are designed to work with AC phase-cut dimmers, then compatibility with existing infrastructure is improved, but circuit complexity increases due to additional control requirements
Solution Approach 1:
The patent designs the switching mode power supply to perform multiple functions: it provides galvanic isolation for safety, enables AC phase-cut dimmer compatibility through synchronized control, and delivers regulated power to LED emitters. This multi-functionality allows the system to work with existing AC phase-cut dimmer infrastructure without requiring separate control systems.
Solution Approach 2:
The patent incorporates a monitoring circuit that detects the phase angle of the AC waveform and provides feedback to the control circuit. This feedback mechanism enables the switching mode power supply to synchronize its operation with AC phase-cut dimmers, allowing dimming control while maintaining stable LED operation.
3Device complexity
If conventional lighting systems are used, then simplicity of design is maintained, but energy efficiency deteriorates due to high power consumption
Solution Approach 1:
The patent changes the operating parameters of the lighting system by using switching mode power supply technology, which operates at high frequencies with efficient switching transitions. This enables much higher energy efficiency compared to conventional linear power supplies, converting electrical energy to light with minimal energy loss while maintaining a relatively simple overall system design.
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 efficiently converts AC power to light, allowing for safe operation with higher AC voltages and effective dimming using AC phase-cut dimmers, improving energy efficiency and power factor control.
Implementation Method 1
a rectifier connected to rectify an AC waveform presented at the power input
Implementation Method 2
a switching mode power supply having a primary side and a secondary side. The secondary side is electrically isolated from the primary side
Data Source
AI summary
Solid state light sources are compatible with AC phase-cut dimmers. The light sources may have switching mode power supplies having primary and secondary sides that are in first and second circuit parts that are electrically isolated from one another. Information regarding a waveform of input electrical power is extracted in the first circuit part and passed to a controller in the second circuit part by way of a galvanic isolator. Additional isolated paths may be provided to provide bi-directional exchange of information between the first and second circuit parts and/or to provide for the exchange of additional information relevant to control. The signal path from the first side to the second side may have a low latency.