MEMS lifetime enhancement

摘要

The present invention generally relates to methods for increasing the lifetime of MEMS devices by reducing the number of movements of a switching element in the MEMS device. Rather than returning to a ground state between cycles, the switching element can remain in the same state if both cycles necessitate the same capacitance. For example, if in both a first and second cycle, the switching element of the MEMS device is in a state of high capacitance the switching element can remain in place between the first and second cycle rather than move to the ground state. Even if the polarity of the capacitance is different in successive cycles, the switching element can remain in place and the polarity can be switched. Because the switching element remains in place between cycles, the switching element, while having the same finite number of movements, should have a longer lifetime.

主权项

1. A method of operating a digital variable capacitor, the digital variable capacitor having a plurality of MEMS devices that each have a switching element, the method comprising:
a first switching process comprising:
switching a first MEMS device of the plurality of MEMS devices to first capacitance state, the switching comprising applying a first bias to a first electrode of the first MEMS device to move the switching element of the first MEMS device from a first position that is electrically grounded to a second position adjacent a second electrode of the first MEMS device; andswitching a second MEMS device of the plurality of MEMS devices to a second state of capacitance, the switching comprising applying a second bias to a first electrode of the second MEMS device to move the switching element of the second MEMS device from a third position that is electrically grounded to a fourth position adjacent a second electrode of the MEMS device, the switching the second MEMS device occurring simultaneous with the switching the first MEMS device; and a second switching process comprising:
switching the first MEMS device to a ground state, the switching comprising removing the first bias to permit the switching element to return to first position; andmaintaining the second bias on the first electrode of the second MEMS device to maintain the switching element of the second MEMS device in the fourth position while the first MEMS device returns to the first position.