Floating Solid-State Switch for Galvanically Isolated Signal Commutation
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Solution Overview
Problem
Existing electric switches lack reliable electrical isolation, particularly when operating in different voltage domains, leading to issues with reliability, aging, and speed due to moving parts in reed switches, and lack of isolation in conventional Hall switches.
Innovation Solution
A solid state circuit comprising a main circuit and a floating circuit with a driver, modulator, demodulator, and output switch, which generates a floating power supply and demodulates control signals to create a galvanically isolated output switch, allowing signal commutation without moving parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a reed switch is used to provide electrical isolation, then electrical isolation is achieved, but reliability deteriorates due to moving parts and contact aging
Solution Approach 1:
The patent replaces the mechanical reed switch system with a solid-state circuit system consisting of a modulator, demodulator, and floating switch. The mechanical moving parts and ferromagnetic contacts are substituted with electronic components that use modulation and demodulation of electrical signals to achieve the same switching function without physical contact or magnetic fields.
Solution Approach 2:
The patent introduces a modulator and demodulator as intermediary components between the control circuit and the floating switch. The modulator converts the control signal into a modulated signal that can be transmitted through the isolated domain, and the demodulator converts it back, serving as an intermediary mechanism to transfer control across the electrical isolation boundary.
2Device complexity
If a Hall switch is used to eliminate moving parts, then reliability improves, but electrical isolation deteriorates
Solution Approach 1:
The patent divides the circuit into two separate domains: a main circuit domain and a floating circuit domain, separated by electrical isolation. The segmentation allows each domain to operate independently at different voltage levels while maintaining control through signal modulation, thus achieving both solid-state reliability and electrical isolation.
Solution Approach 2:
The modulator and demodulator serve as intermediary components that enable control signal transmission across the isolated domains. The modulator in the main circuit converts control signals into a form that can be transmitted through the isolation barrier, and the demodulator in the floating circuit converts it back, maintaining both isolation and control capability.
3Reliability
If a reed switch is used to provide isolation, then electrical isolation is achieved, but switching speed deteriorates
Solution Approach 1:
The patent replaces the slow mechanical reed switch operation with fast solid-state electronic switching. The floating switch controlled by demodulated signals operates electronically without mechanical movement, achieving switching speeds limited only by electronic response times rather than mechanical inertia and contact bounce.
4Reliability
If a reed switch is used to provide isolation, then electrical isolation is achieved, but device size increases
Solution Approach 1:
The patent replaces the bulky mechanical reed switch structure with compact solid-state electronic components. The modulator, demodulator, and floating switch can be implemented as integrated circuits or discrete electronic components that occupy significantly less volume than the mechanical contacts, magnetic fields, and enclosures required by reed switches.
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 solution provides a reliable, solid state switch with electrical isolation from the main power supply, improving reliability and speed by eliminating moving parts and contact aging, while maintaining robustness and efficiency.
Implementation Method 1
a floating power supply comprising at least one rectifier configured for generating a floating supply voltage (VDDF) and a floating ground voltage (VSSF) from the differential driver signal
Data Source
AI summary
A solid state circuit includes a main and a floating circuit including: a first driver for generating a differential driver signal derived from a driver signal; a modulator configured for modulating a modulator signal with another signal to obtain a differential control signal; the floating circuit comprising: a floating power supply comprising at least one rectifier configured for generating a floating supply voltage (VDDF) and a floating ground voltage (VSSF) from the differential driver signal; a demodulator configured for demodulating the differential control signal and for passing the demodulated signal to an output switch; the output switch comprising a first output node and a second output node and at least one transistor configured for opening or closing an electrical path under control of the demodulated signal.