一种双稳态电磁型MEMS开关

A Bi-Stable Electromagnetic MEMS Switch

设计了一种低电压驱动的双稳态电磁型MEMS开关结构,其驱动电压可低于5 V,与驱动电压几十伏的静电型开关相比,应用时无需增加电荷泵等升压电路。开关活动电极含有软磁性材料,可在平面线圈磁场作用下发生翻转,并在均匀永磁磁场作用下保持稳定状态,无功率消耗。同时重点研究了平面线圈磁场和均匀永磁磁场的分布特点,得出了平面线圈工作电流50-100 mA、磁感应强度小于2 mT的工作条件。并最终采用表面牺牲层工艺制作了原理样机,微加工芯片尺寸小于2.5 mm×2.5 mm。经初步测试,其驱动电压小于5 V,触点闭合时接触电阻小于400 mΩ,开关时间小于0.3 ms。

A bi-stable electromagnetic switch structure with the low driving voltage was designed.The switch driving voltage can be lower than 5 V.Compared to the electrostatic type switch with dozens volts driving voltage,the switch can work without the extra driving system such as the charge pump in the application.The moving electrode of the switch is constituted of soft magnet materials,and can reverse under the effect of planar coil magnetic field and keep stable state under the uniform permanent magnet magnetic field without power consumption.The distribution characteristics of the planar coil magnetic field and uniform permanent magnet magnetic field were investigated especially,and the work conditions were obtained.The planar coil work current is 50-100 mA and the magnetic induction intensity is less than 2 mT.Finally,the prototype was fabricated by the surface sacrificial layer technology.The dimension of the switch die is less than 2.5 mm×2.5 mm.The preliminary test shows that the driving voltage is less than 5 V,the contact resistance is less than400 mΩwith the closed contacts,and the switch time is less than 0.3 ms.