MAINTAINING THE STATE OF A MEMS DEVICE IN THE EVENT OF A POWER FAILURE

摘要

A method and apparatus for maintaining the state of a MEMS device in the event of a power failure are disclosed. The apparatus and method may be used with a MEMS device generally having one or more MEMS elements moveably coupled to a substrate that uses electrostatic clamping force to sustain the state of the MEMS element. According to the method, a capacitive or other charge-storing circuit is coupled between a clamping surface and an electrical ground. During normal operation, a clamping voltage is applied between the clamping surface and at least one MEMS element to retain the at least one MEMS element against the clamping surface. In the event of a power failure, the source of the clamping voltage and other circuit paths to ground are isolated from the clamping surface. The charge-storing circuit maintains an electric charge on the clamping surface. Leaky circuit paths to ground may be isolated from the clamping surface by an isolator element configured to electrically isolate the clamping surface in the event of a power failure. The isolator element may include an opto-isolator or a low leakage diode.