PCB Capacitive Isolator for High-Frequency Signal Isolation
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Solution Overview
Problem
Conventional electrical isolation apparatuses, such as optical couplers and isolation transformers, face limitations in frequency applicability and size, with optical couplers having limited frequency capabilities and short service life, and transformers having large size and signal attenuation issues.
Innovation Solution
An electrical isolation apparatus utilizing electric field coupling between conductors, with a primary and secondary stage connected through a first and second transmission circuit and reference circuit, respectively, allowing for high-frequency signal isolation and transmission while reducing size and costs using common metal conductors like PCB material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an optical coupler is used for electrical isolation, then signal isolation is achieved, but the frequency is limited and service life is short
Solution Approach 1:
The patent replaces the optical coupling mechanism (electrical-optical-electrical conversion) with a direct electrical field coupling mechanism through capacitive coupling. This substitution eliminates the frequency limitations and service life issues associated with LED and light-sensitive element aging, while enabling high-frequency signal transmission through pure electrical field interaction between conductors separated by insulation.
2Adaptability or versatility
If an isolation transformer is used for electrical isolation, then high frequency signals can be transmitted, but the device size becomes large
Solution Approach 1:
The patent extracts and eliminates the magnetic core and winding structures from the isolation apparatus. By using direct capacitive coupling between conductors through insulation, the design removes the bulky magnetic components that dominate the size of traditional transformers, while maintaining the ability to transmit high-frequency signals through the simplified conductor-insulator-conductor structure.
Solution Approach 2:
The patent changes the fundamental operating principle from magnetic coupling to electric field coupling. This parameter change in the coupling mechanism allows for a dramatic reduction in device size while maintaining high-frequency signal transmission capability, as the electric field coupling requires only closely spaced conductors separated by thin insulation rather than large magnetic cores.
3Loss of information
If an optical coupler is used, then signal transmission is achieved, but manufacturing costs are high
Solution Approach 1:
The patent employs simple, inexpensive conductor traces and insulation materials that can be manufactured using standard PCB fabrication processes. This replaces expensive optical components (LEDs, light-sensitive elements, encapsulation) with basic electrical components that are much cheaper to produce at scale, while maintaining signal transmission functionality through capacitive coupling.
4Reliability
If an isolation transformer is used, then electrical isolation is achieved, but signal attenuation occurs
Solution Approach 1:
The patent substitutes the magnetic coupling mechanism with direct electrical field coupling through capacitive interaction. This eliminates energy losses associated with magnetic core hysteresis, eddy currents, and winding resistance that cause signal attenuation in transformers. The direct electric field coupling between conductors maintains signal strength while achieving electrical isolation through the insulating barrier.
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
Enables efficient isolation and transmission of high-frequency signals, particularly RF signals, with improved reliability and extended service life, reducing size and manufacturing costs compared to existing solutions.
Implementation Method 1
A signal is transmitted between a first transmission circuit, a first reference circuit, a second transmission circuit, and a second reference circuit according to a principle of electric field coupling between conductors
Data Source
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AI summary
This application provides an electrical isolation apparatus. A signal is transmitted between a first transmission circuit, a first reference circuit, a second transmission circuit, and a second reference circuit according to a principle of electric field coupling between conductors. Therefore, in embodiments, the electrical isolation apparatus can be applied to isolation and transmission for a signal with a relatively high frequency between a first signal device and a second signal device. In addition, a material used by the electrical isolation apparatus may be a common metal conductor, for example, a common PCB material, which greatly reduces a size and costs of the electrical isolation apparatus, and facilitates manufacturing and implementation of the electrical isolation apparatus.