MEMS Switch Controller Actuation to Prevent Contact Stiction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Micro-electromechanical system (MEMS) switching devices face contact stiction issues, where contacts tend to stick together, leading to performance degradation and potential failure, especially in circuit breaker applications where switches are often in a closed state for extended periods.
Innovation Solution
A system incorporating micro-electromechanical switching circuitry with a controller that temporarily opens at least one switch while others remain closed to conduct load current, utilizing over-current protection circuitry to form a conductive path and collapse voltage, preventing contact sticking and arc formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If MEMS switches remain in closed state for extended periods, then system operation is maintained, but contact stiction occurs leading to switching failure
Solution Approach 1:
The controller periodically actuates at least one MEMS switch to an open state for a predetermined time interval, even during normal operation. This periodic opening prevents metal diffusion and contact stiction by interrupting prolonged contact closure, thereby maintaining switching reliability without requiring continuous operation.
2Speed
If solid-state switches are used for high speed switching, then switching speed is improved, but leakage current and voltage drop increase causing power dissipation
Solution Approach 1:
The patent employs MEMS switches that, while having slower switching speed than solid-state devices, provide near-zero leakage current and minimal voltage drop when closed. The periodic actuation strategy allows these mechanical switches to maintain reliability without the continuous power dissipation issues of solid-state alternatives.
3Reliability
If conventional electromechanical switches are used, then robust switching is achieved, but device size and complexity increase
Solution Approach 1:
The patent replaces bulky conventional electromechanical switches with miniaturized MEMS switches that utilize micro-scale mechanical movement. This substitution maintains the robust mechanical switching action while dramatically reducing device size and simplifying the overall switch mechanism through integrated fabrication processes.
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
This approach effectively prevents contact stiction, ensuring reliable operation by allowing each switch to be actuated periodically and reducing power dissipation, thereby enhancing the overall reliability and performance of MEMS switching devices.
Implementation Method 1
MEMS switching devices can offer notable advantages over traditional electromechanical switches... by reverse biasing a solid-state switch, the switch may be transitioned into a non-conducting state
Implementation Method 2
The over-current protection circuitry may be configured to momentarily form an electrically conductive path during the temporary open switching condition
Implementation Method 3
The path is further adapted to collapse a voltage level across the contacts of the switch as the switch returns out of the temporary open switching condition to the closed switching condition
Data Source
AI summary
A system that includes micro-electromechanical system switching circuitry, such as may be made up of a plurality of micro-electromechanical switches, is provided. The plurality of micro-electromechanical switches may generally operate in a closed switching condition during system operation. A controller is coupled to the electromechanical switching circuitry. The controller may be configured to actuate at least one of the micro-electromechanical switches to a temporary open switching condition while a remainder of micro-electromechanical switches remains in the closed switching condition to conduct a load current and avoid interrupting system operation. The temporary open switching condition of the switch is useful to avoid a tendency of switch contacts to stick to one another.