Patent ID: 9503814
Filing Date: 2016-11-22
CPC Classification: H04R

Claim Text:
1. An acoustic apparatus, comprising: a first MEMS motor including a first diaphragm and a first back plate, the first motor configured to create a first differential signal representative of sound energy, wherein a first positive potential is applied to the first diaphragm; a second MEMS motor including a second diaphragm and a second back plate, the second motor configured to create a second differential signal representative of the sound energy, wherein the second diaphragm and the second back plate are flipped mechanically compared to the first diaphragm and the first back plate, and wherein a second positive potential is applied to the second back plate; a first preamplifier circuit coupled to the first MEMS motor, the first preamplifier circuit configured to produce a first pre-amplified signal from the first differential signal; a second preamplifier circuit coupled to the second MEMS motor, the second preamplifier circuit configured to produce a second pre-amplified signal from the second differential signal; and a differential stage coupled to the first preamplifier circuit and the second preamplifier circuit, the differential stage configured to obtain a difference between the first pre-amplified signal and the second pre-amplified signal, wherein the differential stage is disposed on an integrated chip that is different from one or more other integrated chips that include the first preamplifier circuit and the second preamplifier circuit, wherein a first differential bias voltage is created between the first diaphragm and the first back plate to create the first differential signal and a second differential voltage is created between the second diaphragm and the second back plate to create the second differential signal, and wherein common mode noise between the first motor and the second motor is rejected by the differential stage.