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: An apparatus includes a drive signal circuit for MEMS sensor. The drive signal circuit includes an input configured to receive a voltage signal representative of charge generated by the MEMS sensor, a phase-shift circuit electrically coupled to the input and configured to phase shift an input signal by substantially ninety degrees, and a comparator circuit with hysteresis. An input of the comparator is electrically coupled to an output of the phase-shift circuit and an output of the comparator circuit is electrically coupled to an output of the drive signal circuit. A feedback loop extends from the output of the drive signal circuit to the input of the phase-shift circuit and is configured to generate a self-oscillating signal at an output of the drive signal circuit. An output signal generated by the drive signal circuit is applied to a drive input of the MEMS sensor.

Abstract: An apparatus includes a capacitance-to-voltage converter circuit configured to be electrically coupled to a micro-electromechanical system (MEMS) sensor circuit. The capacitance-to-voltage converter circuit includes a differential chopping circuit path configured to receive a differential MEMS sensor output signal and invert a polarity of the differential chopping circuit path, and a differential sigma-delta analog to digital converter (ADC) circuit configured to sample the differential MEMS sensor output signal and provide a digital signal representative of a change in capacitance of the MEMS sensor.

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: 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: 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: An apparatus includes a capacitance-to-voltage converter circuit configured to be electrically coupled to a micro-electromechanical system (MEMS) sensor circuit. The capacitance-to-voltage converter circuit includes a differential chopping circuit path configured to receive a differential MEMS sensor output signal and invert a polarity of the differential chopping circuit path, and a differential sigma-delta analog to digital converter (ADC) circuit configured to sample the differential MEMS sensor output signal and provide a digital signal representative of a change in capacitance of the MEMS sensor.

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: 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.

Abstract: This document discusses, among other things, apparatus and methods quadrature cancelation of sense information 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: 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 includes a drive signal circuit for MEMS sensor. The drive signal circuit includes an input configured to receive a voltage signal representative of charge generated by the MEMS sensor, a phase-shift circuit electrically coupled to the input and configured to phase shift an input signal by substantially ninety degrees, and a comparator circuit with hysteresis. An input of the comparator is electrically coupled to an output of the phase-shift circuit and an output of the comparator circuit is electrically coupled to an output of the drive signal circuit. A feedback loop extends from the output of the drive signal circuit to the input of the phase-shift circuit and is configured to generate a self-oscillating signal at an output of the drive signal circuit. An output signal generated by the drive signal circuit is applied to a drive input of the MEMS sensor.

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: Methods, apparatus and systems for controlling a photovoltaic panel, to output three-phase power while ensuring the power source operates safely include determining a temperature of the photovoltaic panel, determining a voltage provided from the photovoltaic panel, determining a parameter based on the voltage and the temperature and controlling a DC to three-phase power converter based on the determined parameter. The three-phase power converter may be a pulse amplitude modulated current converter (PAMCC), configured to output first, second and third pulse amplitude modulated current pulse from three terminals controlled in timing and phase so that when respective outputs of multiple PAMCCs are connected, each phase of the plurality of PAMCCs is demodulated to produce a three-phase alternating current output. The PAMCC may be controlled through tables of pulse durations based on the determined parameter. The voltage output may be controlled through a fast control loop and through a slower control loop.

Abstract: A method and apparatus for an ultra-high sensitivity, low cost, passive (no battery) low-power energy harvesting data transmitting circuit energy, such as a RFID (Radio Frequency IDentification) tag integrated circuit “chip.” By using combinations of special purpose design enhancements, the low-power energy harvesting passive data transmitting circuit, such as the RFID tag chip, operates in the sub-microwatt power range. The chip power should be derived from a low-microwatt per square centimeter RF field radiated to the RFID tag antenna from the tag reader (interrogator) or derived from a suitable low signal source, such as a sonic transducer (e.g., a piezoelectric transducer or a low level DC source, such as a bimetallic or chemical source).

Abstract: Phase-locked loop (PLL) methods and apparatus are described for generating multiple output clocks synchronized to different frequencies of multiple input signals, wherein the multiple-output PLL employs a single voltage controlled oscillator (VCO). In an embodiment, the base module generates signals with a controlled frequency, multiple equidistant phase, and reduced duty cycles. Frequency dividers using barrel-shifters driven by an early-late detector combined with a left/right “one hot” shift-register or driven by an early-late detector combined with up-down counter/decoder are also disclosed.

Abstract: Methods and devices are disclosed for performing analog to digital signal conversion in shorter time and/or with less power consumption than that of a comparable analog to digital conversion that uses a conventional sequential approximation method based on a binary search. In one embodiment, a predictive guess is supplied as a digital first signal. The digital first signal is converted (D/A) to a counterpart, analog guess signal. A comparison is made between the analog guess signal and a received, analog input sample signal. The result of the comparison is used to improve on the initially supplied guess in a next cycle. Fewer cycles and less power is consumed if the initial guess is within a certain range of the actual magnitude of the analog input sample signal. In one embodiment, a digital modeler is used to model a process underlying the analog input sample signal and to thereby provide fairly good guesses.

Abstract: A system and method of creating a highly efficient digital amplifier which can take either analog or digital inputs, and produce a high power accurate representation of the input to drive speakers or other low impedance load is described. The system employs a transition detector and delay unit which allows the comparator of the signal modulator to ignore its inputs for a pre-determined number of subsequent clock cycles once an output transition has been detected. Through the use of faster clocks and variable clock cycle skips upon the comparator's output transition, finer resolution of the feedback's clock period for noise-shaping purposes is achieved. Finer resolution of the clock period allows the present invention to employ a more aggressive noise-shaping than previously possible.

Abstract: A system and method of creating a highly efficient digital amplifier which can take either analog or digital inputs, and produce a high power accurate representation of the input to drive speakers or other low impedance load is described. The system employs a transition detector and delay unit which allows the comparator of the signal modulator to ignore its inputs for a pre-determined number of subsequent clock cycles once an output transition has been detected. Through the use of faster clocks and variable clock cycle skips upon the comparator's output transition, finer resolution of the feedback's clock period for noise-shaping purposes is achieved. Finer resolution of the clock period allows the present invention to employ a more aggressive noise-shaping than previously possible.

Abstract: A system and method of creating a highly efficient digital amplifier which can take either analog or digital inputs, and produce a high power accurate representation of the input to drive speakers or other low impedance load is described. The system employs a transition detector and delay unit which allows the comparator of the signal modulator to ignore its inputs for a pre-determined number of subsequent clock cycles once an output transition has been detected. Through the use of faster clocks and variable clock cycle skips upon the comparator's output transition, finer resolution of the feedback's clock period for noise-shaping purposes is achieved. Finer resolution of the clock period allows the present invention to employ a more aggressive noise-shaping than previously possible.