Abstract: A digital microphone with a dynamic gain scaling system is provided. An ASIC coupled the microphone to the scaling system. An input buffer, a preamplifier, a pair of switching element, a bias source, and a capacitor coupled to the pair of switching element is integrated into the ASIC. In one embodiment, the scaling system is integrated into the ASIC. In another embodiment, the scaling system is a second ASIC and is coupled to the ASIC. The scaling system includes a ADC, a PDM, and a delta-sigma based BR filter and is configured to dynamically adjust various parameters of the ADC, preamplifier, and the bias source.

Abstract: Microphone systems including a MEMS microphone and an electronic controller. The MEMS microphone includes a movable membrane and a backplate. The movable membrane includes a capacitive electrode and a piezoelectric electrode. The capacitive electrode is configured such that acoustic pressures acting on the movable membrane cause movement of the capacitive electrode. The piezoelectric electrode alters a mechanical property of the MEMS microphone based on a control signal. The backplate is positioned on a first side of the movable membrane. The electronic controller is electrically coupled to the piezoelectric electrode and is configured to generate the control signal.

Abstract: Systems and methods of sensing audio with a MEMS microphone that modulates a frequency of a phase-locked loop. The MEMS microphone includes a movable electrode and a stationary electrode. The phase-locked loop includes a voltage-controlled oscillator and a phase detector. The voltage-controlled oscillator includes a biasing circuit and a plurality of inverters. The biasing circuit is configured to generate a biasing signal based on a control signal. The plurality of inverters are configured to generate an oscillating signal based on the control signal and a capacitance between the movable electrode and the stationary electrode. The phase detector is configured to detect a phase difference between the oscillating signal and a reference signal. The phase detector is also configured to generate the control signal based on the phase difference. The controller is configured to determine an audio signal based on the control signal.

Abstract: Systems for controlling parameters of a MEMS microphone. In one embodiment, the microphone system includes a MEMS microphone and a controller. The MEMS microphone includes a movable electrode, a stationary electrode, and a driven electrode. The movable electrode is configured such that acoustic pressure acting on the movable electrode causes movement of the movable electrode. The stationary electrode and the driven electrode are positioned on a first side of the movable electrode. The driven electrode is configured to alter a parameter of the MEMS microphone based on a control signal. The controller is coupled to the stationary electrode and the driven electrode. The controller is configured to determine a voltage difference between the movable electrode and the stationary electrode. The controller is also configured to generate the control signal based on the voltage difference.

Abstract: Systems for controlling parameters of a MEMS microphone. In one embodiment, the microphone system includes a MEMS microphone and a controller. The MEMS microphone includes a movable electrode, a stationary electrode, and a driven electrode. The movable electrode is configured such that acoustic pressure acting on the movable electrode causes movement of the movable electrode. The stationary electrode and the driven electrode are positioned on a first side of the movable electrode. The driven electrode is configured to alter a parameter of the MEMS microphone based on a control signal. The controller is coupled to the stationary electrode and the driven electrode. The controller is configured to determine a voltage difference between the movable electrode and the stationary electrode. The controller is also configured to generate the control signal based on the voltage difference.

Abstract: Microphone systems including a MEMS microphone and an electronic controller. The MEMS microphone includes a movable membrane and a backplate. The movable membrane includes a capacitive electrode and a piezoelectric electrode. The capacitive electrode is configured such that acoustic pressures acting on the movable membrane cause movement of the capacitive electrode. The piezoelectric electrode alters a mechanical property of the MEMS microphone based on a control signal. The backplate is positioned on a first side of the movable membrane. The electronic controller is electrically coupled to the piezoelectric electrode and is configured to generate the control signal.

Abstract: Extending a microphone interface. One microphone interface extension includes a controller, a parent microphone, and a child microphone. The controller outputs a controller clock signal. The parent microphone receives the controller clock signal and generates a first data signal. The child microphone generates a second data signal and outputs the second data signal to the first parent microphone. The parent microphone receives the second data signal from the child microphone and outputs a combined data signal to the controller based on the first data signal and the second data signal. The parent microphone outputs the combined data signal to the controller on a phase of a microphone clock signal derived from the controller clock signal.

Abstract: Systems and methods for controlling parameters of a MEMS microphone. The microphone system includes a MEMS microphone and a controller. The MEMS microphone includes a movable electrode, a stationary electrode, and a driven electrode. The movable electrode has a first side and a second side that is opposite the first side. The movable electrode is configured such that acoustic pressures acting on the first side and the second of the movable electrode cause movement of the movable electrode. The stationary electrode is positioned on the first side of the movable electrode. The driven electrode is configured to receive a control signal and alter a parameter of the MEMS microphone based on the control signal. The controller is configured to determine a voltage difference between the movable electrode and the stationary electrode. The controller is also configured to generate the control signal based on the voltage difference.

Abstract: Systems and methods of sensing audio with a MEMS microphone that modulates a frequency of a phase-locked loop. The MEMS microphone includes a movable electrode and a stationary electrode. The phase-locked loop includes a voltage-controlled oscillator and a phase detector. The voltage-controlled oscillator includes a biasing circuit and a plurality of inverters. The biasing circuit is configured to generate a biasing signal based on a control signal. The plurality of inverters are configured to generate an oscillating signal based on the control signal and a capacitance between the movable electrode and the stationary electrode. The phase detector is configured to detect a phase difference between the oscillating signal and a reference signal. The phase detector is also configured to generate the control signal based on the phase difference. The controller is configured to determine an audio signal based on the control signal.

Abstract: Systems and methods of sensing audio with a MEMS microphone that modulates a frequency of a phase-locked loop. The MEMS microphone includes a movable electrode and a stationary electrode. The movable electrode is configured such that acoustic pressures acting on the movable electrode cause movement of the movable electrode. A voltage-controlled oscillator of the phase-locked loop is coupled to the MEMS microphone and receives a control signal. The voltage-controlled oscillator also generates an oscillating signal based on the control signal and a capacitance between the movable electrode and the stationary electrode. A phase detector of the phase-locked loop receives and determines a phase difference between the oscillating signal and a reference signal. The phase detector further generates the control signal based on the phase difference. A controller is configured to receive the control signal and determine an audio signal based on the control signal.

Abstract: An adjustable microphone. The microphone includes a MEMS microphone, a charge pump, a preamplifier, a first analog-to-digital converter, a root mean square (RMS) power detector, and a logic circuit. The MEMS microphone is configured to provide a signal indicative of sound detected by the MEMS microphone. The charge pump provides a bias voltage to the MEMS microphone. The preamplifier receives the signal from the MEMS microphone, and outputs an amplified signal indicative of sound detected by the MEMS microphone. The first analog-to-digital converter receives the amplified signal and converts the amplified signal to a digital signal. The root mean square power detector is configured to detect a power level of the amplified signal and output an indication of the power of the amplified signal. The logic circuit receives the RMS power detector output and a control input, and adjusts the operation of the microphone based on the control input.

Abstract: Extending a microphone interface. One microphone interface extension includes a controller, a parent microphone, and a child microphone. The controller outputs a controller clock signal. The parent microphone receives the controller clock signal and generates a first data signal. The child microphone generates a second data signal and outputs the second data signal to the first parent microphone. The parent microphone receives the second data signal from the child microphone and outputs a combined data signal to the controller based on the first data signal and the second data signal. The parent microphone outputs the combined data signal to the controller on a phase of a microphone clock signal derived from the controller clock signal.

Abstract: Extending a microphone interface. One microphone interface extension includes a controller, a parent microphone, and a child microphone. The controller outputs a controller clock signal. The parent microphone receives the controller clock signal and generates a first data signal. The child microphone generates a second data signal and outputs the second data signal to the first parent microphone. The parent microphone receives the second data signal from the child microphone and outputs a combined data signal to the controller based on the first data signal and the second data signal. The parent microphone outputs the combined data signal to the controller on a phase of a microphone clock signal derived from the controller clock signal.

Abstract: Systems and methods of sensing audio with a MEMS microphone that modulates a frequency of a phase-locked loop. The MEMS microphone includes a movable electrode and a stationary electrode. The movable electrode is configured such that acoustic pressures acting on the movable electrode cause movement of the movable electrode. A voltage-controlled oscillator of the phase-locked loop is coupled to the MEMS microphone and receives a control signal. The voltage-controlled oscillator also generates an oscillating signal based on the control signal and a capacitance between the movable electrode and the stationary electrode. A phase detector of the phase-locked loop receives and determines a phase difference between the oscillating signal and a reference signal. The phase detector further generates the control signal based on the phase difference. A controller is configured to receive the control signal and determine an audio signal based on the control signal.

Abstract: Systems and methods for controlling parameters of a MEMS microphone. The microphone system includes a MEMS microphone and a controller. The MEMS microphone includes a movable electrode, a stationary electrode, and a driven electrode. The movable electrode has a first side and a second side that is opposite the first side. The movable electrode is configured such that acoustic pressures acting on the first side and the second of the movable electrode cause movement of the movable electrode. The stationary electrode is positioned on the first side of the movable electrode. The driven electrode is configured to receive a control signal and alter a parameter of the MEMS microphone based on the control signal. The controller is configured to determine a voltage difference between the movable electrode and the stationary electrode. The controller is also configured to generate the control signal based on the voltage difference.

Abstract: An adjustable microphone. The microphone includes a MEMS microphone, a charge pump, a preamplifier, a first analog-to-digital converter, a root mean square (RMS) power detector, and a logic circuit. The MEMS microphone is configured to provide a signal indicative of sound detected by the MEMS microphone. The charge pump provides a bias voltage to the MEMS microphone. The preamplifier receives the signal from the MEMS microphone, and outputs an amplified signal indicative of sound detected by the MEMS microphone. The first analog-to-digital converter receives the amplified signal and converts the amplified signal to a digital signal. The root mean square power detector is configured to detect a power level of the amplified signal and output an indication of the power of the amplified signal. The logic circuit receives the RMS power detector output and a control input, and adjusts the operation of the microphone based on the control input.

Abstract: A bit stream includes playback data having an associated clock rate and a variable reference clock that is synchronized to the bit stream. A playback clock recovery signal and a data recovery signal are generated in response to the received reference clock. A playback clock frequency signal is generated in response to the playback clock recovery signal. A recovered playback clock is generated by using a divide by M divider, wherein the value of M used by the divide by M divider is determined in response to a programmable multiple of the clock rate associated with the playback information.

Abstract: Systems and methods for adjusting a bias voltage and gain of the microphone to account for variations in a thickness of a gap between a movable membrane and a stationary backplate in a MEMS microphone due to the manufacturing process. The microphone is exposed to acoustic pressures of a first magnitude and a sensitivity of the microphone is evaluated according to a predetermined sensitivity protocol. The bias voltage of the microphone is adjusted when the microphone does not meet the sensitivity protocol. The microphone is then exposed to acoustic waves of a second magnitude that is greater than the first magnitude and a stability of the microphone is evaluated according to a predetermined stability protocol. The bias voltage and the gain of the microphone are adjusted when the microphone does not meet the stability protocol.

Abstract: Extending a microphone interface. One microphone interface extension includes a controller, a parent microphone, and a child microphone. The controller outputs a controller clock signal. The parent microphone receives the controller clock signal and generates a first data signal. The child microphone generates a second data signal and outputs the second data signal to the first parent microphone. The parent microphone receives the second data signal from the child microphone and outputs a combined data signal to the controller based on the first data signal and the second data signal. The parent microphone outputs the combined data signal to the controller on a phase of a microphone clock signal derived from the controller clock signal.

Abstract: A semiconductor microphone including a silicon substrate having a perimeter; an N-well diffused into the substrate at the perimeter; a deformable diaphragm disposed over at least a portion of the silicon substrate and in contact with at least a portion of the perimeter; and a signal channel in electrical communication with the diaphragm. The signal channel includes a microphone output channel and a feedback output channel. The diaphragm produces an electric signal on the signal channel in response to deformation of the diaphragm and a portion of the electric signal is transmitted on the feedback output channel to the N-well.