A High-Electrical-Reliability MEMS Inertial Switch Based on Latching Mechanism and Debounce Circuit

A novel high-electrical-reliability microelectromechanical systems (MEMS) inertial switch based on latching mechanism and debounce circuit was proposed, fabricated, and tested in this paper. The latching mechanism consists of a pair of L-shaped hooks, an arrow lock, and a couple of support springs that are set to stabilize the contact between anode and cathode, mechanically. Two symmetric tension-type L-shaped hooks were chosen to avoid instability failure. The spring-type soft contact between two electrodes was adopted to improve electrical performance of the switch. In addition, an RC debounce circuit was designed and experimentally tested to remove a small amount of bounce from the output voltage. Two sets of experiments, namely, a shock test and a vibration test (rotation and swing), were carried out to evaluate the electrical reliability of the switch. A series of experimental results shows that the combination of the novel structures and the RC debounce circuit can efficiently eliminate unwanted bounces between the two electrodes. In addition, the noises that come from the previous analog circuit can be removed to guarantee the electrical reliability of the MEMS inertial switch.