MEMS Circuit Breaker Switch With Optical Isolation and Beam Stopper
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Solution Overview
Problem
MEMS switches face challenges in reliably operating between input and output terminals with large voltage differences for extended periods due to structural degradation from repeated switching operations.
Innovation Solution
A micro-electromechanical (MEMS) switch design featuring a conductive beam anchored by a conductive post, with a mechanical stopper and control electrodes, allowing the beam to tilt and form conductive paths while suppressing elastic deformation, and incorporating isolation circuits and protective switches to manage high voltage and current applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If MEMS switch structure is used for high voltage and high current applications, then switching capability is improved, but structural degradation occurs due to repeated switching operations
Solution Approach 1:
The patent divides the MEMS switch into multiple independent components: a conductive beam, a conductive post, contact electrodes, and a mechanical stopper. This segmentation allows each component to perform its specific function while reducing the mechanical stress burden on any single structure, thereby improving overall reliability under high power conditions
Solution Approach 2:
The conductive post is positioned asymmetrically on the conductive beam, closer to one end than the other. This asymmetric positioning optimizes the mechanical leverage and electrical connection points, allowing the switch to handle high voltage and current while distributing mechanical stress more effectively during repeated switching operations
2Ease of operation
If conductive beam is designed to tilt for switching operation, then switching function is improved, but elastic deformation increases reducing reliability
Solution Approach 1:
The mechanical stopper is pre-positioned beneath the conductive beam at a specific location. Before the switching operation begins, the stopper is already in place to limit the tilt angle of the conductive beam, preventing excessive elastic deformation while still allowing sufficient movement for effective switching contact
Solution Approach 2:
The mechanical stopper acts as an intermediary element between the conductive beam and the substrate. It mediates the tilt motion by providing a physical constraint that prevents the beam from deforming beyond a safe angle, thereby protecting the beam from excessive elastic stress while maintaining switching functionality
3Reliability
If mechanical stopper is added to suppress elastic deformation, then reliability is improved, but device complexity increases
Solution Approach 1:
The mechanical stopper is merged with the substrate structure, forming an integrated component rather than a separate movable part. This merging approach adds the reliability benefit of elastic deformation suppression while minimizing the increase in device complexity, as the stopper becomes part of the fixed substrate architecture
Solution Approach 2:
The mechanical stopper serves multiple functions: it limits the tilt angle of the conductive beam, provides a mechanical reference point for switching operation, and distributes mechanical stress during actuation. This multi-functionality justifies the added component by delivering multiple reliability benefits simultaneously
4Reliability
If optical isolation is implemented for high voltage isolation, then electrical isolation is improved, but device complexity increases
Solution Approach 1:
The patent replaces traditional electrical isolation methods with optical isolation using an optical isolator. This substitution provides superior electrical isolation for high voltage applications by using light instead of electrical signals for control, while the integrated design minimizes the added circuit complexity
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 design enhances the reliability and durability of MEMS switches for high voltage and current applications by reducing mechanical stress and maintaining electrical isolation, thereby extending the switch's operational lifespan and preventing arcing.
Implementation Method 1
the conductive beam is configured to tilt such that one side of the conductive beam contacts one of the pair of contact electrodes to form a further conductive path
Implementation Method 2
the mechanical stopper is configured to substantially suppress an elastic deformation of one or both of the conductive beam and the conductive post
Implementation Method 3
a conductive post serving simultaneously as a mechanical pivot and a conductive path between the conductive beam and a middle electrode on the substrate
Data Source
AI summary
High voltage micro-electromechanical systems (MEMS) switches are described. A MEMS teeter-totter switch can include a beam coupled to an anchor on a substrate and two control electrodes, disposed on a surface of the substrate. A control circuit may include an optical isolator that provides an isolated activation voltage to a voltage supply and control circuit. The voltage supply and control circuit uses the isolated activation voltage to supply a control voltage to one of the control electrodes with respect to a first reference voltage, causing the beam to provide an input voltage received from an input terminal to a contact electrode of the MEMS teeter-totter switch electrically connected to an output terminal. The input voltage is applied on the beam with respect to a second reference voltage different from the first reference voltage.