MEMS Switch Balancing Module for Parasitic Charge Equalization
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Solution Overview
Problem
MEMS switches/relays are prone to failure due to parasitic capacitance-induced charge imbalances and hot-switching, which lead to premature wear and damage, reducing their cycle life and reliability.
Innovation Solution
A micro-machined switching system with a balancing module using bi-directional DMOS circuitry to equalize charge between input and output, and a switch controller that inhibits signal drivers during state changes to prevent hot-switching, ensuring balanced charge and preventing current surges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a MEMS relay is used to create a near ideal switch, then switching performance is improved, but the device becomes sensitive to charge imbalances from parasitic capacitances, causing beam pitting and welds that reduce cycle life
Solution Approach 1:
The patent applies preliminary action by equalizing the charge on parasitic capacitances at the input and output of the MEMS relay before the switching operation. The balancing module proactively balances the charge states, preventing the charge imbalance that would otherwise cause beam pitting and welds during switching, thereby extending cycle life while maintaining switching performance
Solution Approach 2:
The patent introduces a balancing module as an intermediary component between the signal paths. This module includes switches that can equalize the charge on parasitic capacitances, acting as a mediator to prevent charge imbalance from damaging the MEMS relay beam, thus protecting the device while preserving its ideal switching characteristics
2Productivity
If hot-switching occurs during state change, then signal transmission is maintained, but large current surges and arching damage the beam and cause switch failure
Solution Approach 1:
The patent applies preliminary anti-action by implementing control logic that prevents signal transmission during the critical state-change period. The system proactively inhibits hot-switching by controlling when signals are allowed to pass, preventing the large current surges and arching that would damage the beam, while still maintaining overall signal transmission continuity through proper timing control
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 significantly extends the life of MEMS switches/relays by eliminating parasitic capacitance discharges and hot-switching, enabling reliable operation across numerous cycles by maintaining charge balance and preventing damage from current surges.
Implementation Method 1
parasitic capacitance formed at an input and an output of a micro-machined switching device
Implementation Method 2
Hot-switching occurs when a signal is driven along the signal path while the MEMS switch/relay is changing states. As the beam of the MEMS switch/relay deflects and comes partially into contact with the signal path sections, the driven signal can cause a large current surge and arching.
Implementation Method 3
a cantilevered beam 101 that bends as the result of electrostatic forces due to the presence of a voltage 105 at the gate 102 of the MEMS relay 100
Data Source
AI summary
A micro-machined switching system for equalizing an electrical property, such as charge due to parasitic capacitance formed at an input and an output of a micro-machined switching device. The micro-machined switching device may be a MEMS relay or a MEMS switch. In addition to the micro-machined switching device, the switching system also includes a balancing module for equalizing the electrical property between the input and the output of the micro-machined switching device. In certain embodiments, the balancing module includes a switch operable in a first state causing charge due to the parasitic capacitance on the input and the output of the micro-machined switching device to substantially balance. The switch is also operable in a second state wherein parasitic capacitance can separately accumulate at the input and the output of the micro-machined switching device.