Patent ID: 8646308

Claim:
A method for self testing a MEMS device comprising: providing the MEMS device having a first reciprocally movable MEMS body carrying a first movable electrode establishing a capacitance with a first fixed electrode and a second reciprocally movable MEMS body carrying a second movable electrode establishing a capacitance with a second fixed electrode, each MEMS body movable in response to an applied acceleration; applying a self-test voltage such that one of the MEMS bodies is urged to move against the movement it would naturally follow in response to an applied physical acceleration and the other MEMS body is urged to move in sympathy with the movement it would naturally follow in response to the same applied physical acceleration; and applying self-test signals to at least one of the first and second fixed electrodes and the first and second movable electrodes so as to produce a common mode output signal from at least one of the first and second movable electrodes and the first and second fixed electrodes in response to physical acceleration of the MEMS device and to produce a differential output signal from the at least one of the first and second movable electrodes and the first and second fixed electrodes in response to unnatural repositioning of the first and second movable electrodes.