Abstract: A charge pump includes a first unidirectional conducting device, a flying capacitor, a second unidirectional conducting device, an output capacitor, a first switch, and a second switch. The first unidirectional conducting device unidirectionally couples a supply voltage to an internal node. The flying capacitor is coupled between the internal node and a clock signal. The second unidirectional conducting device unidirectionally couples the internal node to an output node. The output capacitor is coupled between the output node and a ground. The first switch couples a discharge node to the ground according to a discharge signal. The second switch couples the output node to the discharge node according to the voltage of the internal node.

Abstract: This document provides apparatus and methods for cancelation of quadrature error from a micro-electromechanical system (MEMS) device, such as a MEMS gyroscope. In certain examples, a quadrature correction apparatus can include a drive charge-to-voltage (C2V) converter configured to provide drive information of a proof mass of a MEMS gyroscope, a sense C2V converter configured to provide sense information of the proof mass, a phase-shift module configured to provide phase shift information of the drive information, a drive demodulator configured to receive the drive information and the phase shift information and to provide demodulated drive information, a sense demodulator configured to receive the sense information and the phase shift information and to provide demodulated sense information, and wherein the quadrature correction apparatus is configured to provide corrected sense information using the demodulated drive information and the demodulated sense information.

Abstract: An unobtrusive augmented reality (AR) system can be used to assist the wearer in every day interactions by projecting information from the contact lens display onto the retina of the wearer's eye. The unobtrusive augmented reality system includes a necklace and a contact lens display that are unobtrusive to the wearer and the wearer's surrounding environment. The necklace of the unobtrusive augmented reality system generates power and data for the contact lens displays. The necklace and contact lens display include conductive coils inductively coupled by a magnetic field. The inductive coupling allows data and power generated by the necklace to be transferred to the contact lens display. A projector in the contact lens display projects images generated from the data onto the retina of the wearers eye.

Abstract: A digital microphone is provided. The digital microphone includes an acoustic sensor, a bias generator, first and second attenuators, a buffer, an amplifier, an ADC, and a controller. The acoustic sensor transfers an acoustic signal to a voltage signal. The bias generator provides a bias voltage to the acoustic sensor. The first attenuator attenuates the voltage signal by a first attenuation value. The buffer buffers the voltage signal to generate a buffered voltage signal. The amplifier amplifies the buffered voltage signal to generate an amplified signal. The ADC converts the amplified signal to a data signal with a digital format. The second attenuator attenuates the data signal by a second attenuation value. The controller determines whether the amplified signal is larger than a reference value and adjusts the bias voltage and the first and second attenuation values of the first and second attenuators according to the result determined by the controller.

Abstract: A circuit for biasing a transducer including a first plate and a second plate includes a front-end buffer and a charge pump. The front-end buffer generates an internal signal at an internal node in response to a voltage signal of the second plate. The transducer receives the incident sound wave at the first plate to generate the voltage signal at the second plate. The charge pump boosts the internal signal into a boost voltage at the first plate according to a first clock signal.

Abstract: A charge pump includes a first unidirectional conducting device, a flying capacitor, a second unidirectional conducting device, an output capacitor, a first switch, and a second switch. The first unidirectional conducting device unidirectionally couples a supply voltage to an internal node. The flying capacitor is coupled between the internal node and a clock signal. The second unidirectional conducting device unidirectionally couples the internal node to an output node. The output capacitor is coupled between the output node and a ground. The first switch couples a discharge node to the ground according to a discharge signal. The second switch couples the output node to the discharge node according to the voltage of the internal node.

Abstract: Apparatus and methods for interfacing with a micro-electromechanical system (MEMS) sensor are provided. In an example, an apparatus can interface circuit including an integrator circuit, a sample switch circuit, a saturation detector and a controller. The saturation detector can be configured to receive a signal indicative of an integration of charge of the sensor, to compare the signal indicative of the integration of charge to an integrator saturation threshold and to modulate a divide parameter using the comparison of the signal indicative of the integration of charge and the integrator saturation threshold. The controller can be configured to receive a clock signal and to control the sample switch circuit based on a phase of the clock signal and the divide parameter.

Abstract: This document discusses, among other things, a temperature and power supply calibration system configured to compensate for temperature and supply voltage variation in MEMS or other circuits using representations of positive and negative supply voltages and first and second base-emitter voltages, wherein the second base-emitter voltage is a scaled representation of the first base-emitter voltage.

Abstract: Disclosed are systems, devices, circuits, components, mechanisms, and processes in which a switching mechanism can be coupled between components. The switching mechanism is configured to have an on state or an off state, where the on state allows current to pass along a current path. A monitoring mechanism has one or more sensing inputs coupled to sense an electrical characteristic at the current path. The electrical characteristic can be a current, voltage, and/or power by way of example. The monitoring mechanism is configured to output a reporting signal indicating the sensed electrical characteristic. The monitoring mechanism can be integrated with the switching mechanism on a chip.

Abstract: This application discusses simplified interface circuits for a gyroscope. In an example, an interface can include an automatic gain control (AGC) circuit configured to couple to driver for a proof mass of a gyroscope sensor and to drive the proof-mass to oscillate at a predefined oscillation amplitude, and a phase-locked loop (PLL) configured to receive sensed oscillation information from the proof-mass and to provide at least a first phase signal synchronized with a sinusoidal waveform of the sensed oscillation information.

Abstract: In certain examples, a quadrature cancellation apparatus can include a drive charge amplifier configured to couple to a proof mass of a MEMS device and to provide oscillation motion information, a first sense charge amplifier configured to couple to the proof mass and to provide first sense information of a first movement of the MEMS device, a first programmable amplifier configured to receive the oscillation motion information and provide amplified oscillation motion information, a first summer configured to cancel quadrature error of the first sense information using the first sense information and the amplified oscillation motion information to provide quadrature-corrected first sense information, a phase shifter configured to receive the oscillation motion information and to provide carrier information, and a first multiplier configured to provide demodulated first sense information using the quadrature-corrected first sense information and the carrier information.

Abstract: This document discusses, among other things, apparatus and methods for digital automatic gain control for driving a MEMS device, such as a proof mass. In an example, an apparatus can include a driver configured to oscillate a proof mass of a MEMS device, a charge-to-voltage (C2V) converter configured to provide oscillation information of the proof mass, an analog-to-digital converter (ADC) configured to provide a digital representation of the oscillation information, and a digital, automatic gain control circuit to provide oscillation amplitude error information using a comparison of the oscillation information to target amplitude information, and to provide a digital drive command signal using an amplified representation of the oscillation amplitude error information.

Abstract: An apparatus comprises a micro-electromechanical system (MEMS) sensor including a first capacitive element and a second capacitive element and an integrated circuit (IC). The IC includes a switch network circuit and a capacitance measurement circuit. The switch network circuit is configured to electrically decouple the first capacitive element of the MEMS sensor from a first input of the IC and electrically couple the second capacitive element to a second input of the IC. The capacitance measurement circuit can be configured to measure capacitance of the second capacitive element of the MEMS sensor during application of a first electrical signal to the decoupled first capacitive element.

Abstract: This document discusses, among other things, apparatus and methods for a front-end charge amplifier. In certain examples, a front-end charge amplifier for a microelectromechanical system (MEMS) device can include a charge amplifier configured to couple to the MEMS device and to provide sense information of a proof mass of the MEMS device, a feedback circuit configured to receive the sense information and to provide feedback to an input of the charge amplifier, and wherein the charge amplifier includes a transfer function having a first pole at a first frequency, a second pole at a second frequency, and one zero at a third frequency.

Abstract: This application discusses, among other things, simplified interface circuits for a gyroscope. In an example, a interface can include an automatic gain control (AGC) circuit configured to couple to driver for a proof mass of a gyroscope sensor and to drive the proof-mass to oscillate at a predefined oscillation amplitude, and a phase-locked loop (PLL) configured to receive sensed oscillation information from the proof-mass and to provide at least a first phase signal synchronized with a sinusoidal waveform of the sensed oscillation information.

Abstract: Apparatus and methods for analog-to-digital converters are provided. In an example, a sigma-delta analog-to-digital converter (ADC) can include a modulator configured to receive an analog signal and a decimation filter configured to provide a digital representation of the analog signal using an output of the modulator. In certain examples, the modulator can includes an integrator and a comparator od quantizer coupled to an output of the integrator. The comparator, in certain examples, can be configured to receive a second signal from the output of the integrator and to receive a plurality of dither signals, the dither signals can be configured to prevent limit cycles of the sigma-delta ADC.

Abstract: Apparatus and methods for interfacing with a micro-electromechanical system (MEMS) sensor are provided. In an example, an apparatus can interface circuit including an integrator circuit, a sample switch circuit, a saturation detector and a controller. The saturation detector can be configured to receive a signal indicative of an integration of charge of the sensor, to compare the signal indicative of the integration of charge to an integrator saturation threshold and to modulate a divide parameter using the comparison of the signal indicative of the integration of charge and the integrator saturation threshold. The controller can be configured to receive a clock signal and to control the sample switch circuit based on a phase of the clock signal and the divide parameter.

Abstract: Apparatus and methods for analog-to-digital converters are provided. In an example, a sigma-delta analog-to-digital converter (ADC) can include a modulator configured to receive an analog signal and a decimation filter configured to provide a digital representation of the analog signal using an output of the modulator. In certain examples, the modulator can includes an integrator and a comparator od quantizer coupled to an output of the integrator. The comparator, in certain examples, can be configured to receive a second signal from the output of the integrator and to receive a plurality of dither signals, the dither signals can be configured to prevent limit cycles of the sigma-delta ADC.

Abstract: In an example, a driver for a micro-electro-mechanical-system (MEMS) device can include a first input configured to receive a first command signal including an oscillatory command signal, a second input configured to receive a second command signal including a bias command signal, and an amplifier configured to receive a high voltage supply, to provide, to the MEMS device, a closed-loop output signal responsive to both the first command signal and the second command signal in a first state, and to provide an open loop output signal configured to substantially span a voltage range of the high voltage supply in a second state.

Abstract: An apparatus includes a MEMS gyroscope sensor including a first sensing capacitor and a second sensing capacitor and an IC. The IC includes a switch circuit configured to electrically decouple the first sensing capacitor from a first input of the IC and electrically couple the second sensing capacitor to a second input of the IC, and a capacitance measurement circuit configured to measure capacitance of the second sensing capacitor of the MEMS gyroscope sensor during application of a first electrical signal to the decoupled first capacitive element.