Abstract: Provided herein are apparatus and methods for low distortion composite amplifiers with high load current. In certain configurations, a composite amplifier can be a closed loop system which includes two or more amplifiers such that one or more amplifiers can provide an output current to a load while one or more amplifiers can control an output voltage to be proportional to an input voltage. The loop gain can be proportional to the product of the individual amplifier gains and to a noise gain network function. In this way the composite amplifier can maintain low distortion for heavier loads and for load currents which exceed the normal load current operation of a single amplifier.

Abstract: Apparatus and methods are disclosed related to tuning a resonant frequency of an LC circuit. In some implementations, the LC circuit can be embodied in a low noise amplifier (LNA) of a receiver. The receiver can include a component configured to generate an indicator of received signal strength indication (RSSI) of a radio frequency (RF) signal received by the receiver. A control block can adjust the resonant frequency of the LC circuit based at least in part on the indicator of RSSI. As another example, the receiver can include an oscillator, such as a VCO, separate from the LC circuit that can be used to tune the resonant frequency of the LC circuit. These apparatus can compensate for variation in a zero imaginary component of an impedance across the LC circuit.

Abstract: An analog-to-digital converter (ADC) system can sample an input voltage for at least a first conversion into a first N1-bit digital value and to use the same input voltage sample for at least a second conversion into a second N2-bit digital value. A difference between a result of the first conversion and a result of the second conversion can be driven toward zero to adjust weights of one or more of the bits to calibrated values for use in one or more subsequent analog-to-digital conversions of subsequent samples of the input voltage. Shuffling, dithering, or the like can help ensure that at least a portion of the decision paths used in the second conversion are different from the decision paths used in the first conversion. Calibration can be performed in the background while the the ADC is converting in a normal mode of operation.

Abstract: The cap wafer for a MEMS device includes multiple electrically isolated electrodes that can be bonded and electrically connected to separate electrical contacts on a MEMS device wafer. The electrically isolated electrodes can be used for any of a variety of functions, such as for apply a force to a movable MEMS structure on the MEMS device wafer (e.g., for driving resonance of the movable MEMS structure or for adjusting a resonance or sense mode of the movable MEMS structure) or for sensing motion of a movable MEMS structure on the MEMS device wafer. Since the electrodes are electrically isolated, different electrodes may be used for different functions.

Abstract: Optical systems can emit train(s) of light pulses onto objects to derive a distance between the light source and the object. Achieving meter or centimeter resolution may require very short light pulses. It is not trivial to design a circuit that can generate narrow current pulses for driving a diode that emits the light pulses. An improved driver circuit has a pre-charge path comprising one or more inductive elements and a fire path comprising the diode. Switches in the driver circuit are controlled with predefined states during different intervals to pre-charge current in the one or more inductive elements prior to flowing current through the fire path to pulse the diode.

Abstract: A pipeline analog-to-digital converter (ADC) converts an analog input signal over several stages, where a stage generates a residue for the subsequent stage to digitize. The residue is generated by coarsely quantizing the analog input signal to generate a digital code, which is used to reconstruct the analog input signal, and the residue is the difference between the analog input signal and the reconstructed version of the analog input signal. The coarse quantization can have errors which are attributed to comparator offsets and bandwidth mismatch. To estimate the comparator offsets while being insensitive to bandwidth mismatch, peak and trough detectors are used to track maximum and minimum values of the residue or the output of the ADC over time, and an expected value estimating the comparator offset can be computed based on the maximum and minimum values. The expected value advantageously “averages” out the bandwidth mismatch contribution to the offset.

Abstract: Embodiments of the present invention are directed to an improved battery packaging design. The battery pack design may include a battery cell, a plurality of transistors, and a controller. The transistors may be coupled to the terminals of the battery cell in an H-bridge configuration. The controller may control the transistors to bypass the battery cell based on the current flowing between the output terminals of the battery pack. In such a manner, the controller may prevent damage to the battery cell and improve the overall safety of the battery pack in hazardous conditions.

Abstract: Mechanical resonating structures are described, as well as related devices and methods. The mechanical resonating structures may have a compensating structure for compensating temperature variations.

Abstract: Methods and apparatus for sensing linear acceleration with a MEMS resonator mass, alone, or concurrently with sensing rate of rotation. A resonator mass, which may be a disk or a ring structure, is driven at a resonance frequency of one of the vibration modes of the resonator mass. The amplitude of vibration of that mode is sensed by a set of at least two drive-sense electrodes disposed at opposing positions across the resonator mass. A linear acceleration is derived based at least on a difference between signals of the opposing electrodes. Linear acceleration may be sensed in multiple orthogonal dimensions using multiple pairs of opposing electrodes. Rotation rate may be derived concurrently by sensing the energy coupled into an orthogonal mode of the resonator mass.

Abstract: A method of producing a super-capacitor provides a first substrate having a first base, forms a first electrode on the first substrate, and forms a separator so that the electrode is between the first base and the first separator. The method also micromachines holes through the separator, forms a chamber, and adds electrolyte, having ions, to the chamber. The electrolyte is in contact with the first electrode within the chamber. In addition, the holes are sized to permit transmission of the ions of the electrolyte through the holes.

Abstract: A capacitive fluid flow sensor and methods for measuring fluid flow are disclosed herein. An exemplary capacitive fluid flow sensor includes an airfoil having a flexible surface, and a capacitive sensor disposed within the airfoil. A capacitance of the capacitive sensor modulates as the flexible surface deflects in response to fluid flow. The fluid flow sensor may be secured within a cooled equipment enclosure, where the flexible surface of the airfoil deflects in response to fluid flow, such as airflow, within the cooled equipment enclosure.

Abstract: An approach to linearization relaxes the requirements on the digitization of the analog output signal while maintaining the benefits of a high sampling rate of the output signal. The digitization approach extracts sufficient information to characterize the output signal over a wide bandwidth without necessarily determining sufficient information to fully represent the output signal, for example, without sampling the output signal at the Nyquist sampling rate with a sufficient precision to accurately represent the signal.

Abstract: A circuit, system, machine-readable storage medium and method for detecting the presence of a leakage path in a multi-cell voltage source is described. The system includes a detection circuit, the detection circuit having a first, second and third amplifiers, a first input of the first amplifier connected to a first terminal of the voltage source and the first input of the second amplifier connected to a second terminal of the voltage source, a second input of each of the first and second amplifiers connected to a reference capacitor, and an output of each of the first, second and third amplifiers connected to a respective first, second and third outputs of the detection circuit; and a processor having inputs connected to the first and second outputs of the detection circuit.

Abstract: One aspect of this disclosure is a transimpedance amplifier circuit with multiple resistive feedback loops can be implemented with multiple Kelvin sensing channels. A transimpedance amplifier and multiple Kelvin sensing channels can be implemented on a single die having multiple contacts, such as pins, for connecting multiple resistors to the Kelvin sensing channels. The Kelvin sensing channels can be implemented with T-junction switch networks in certain embodiments.

Abstract: Apparatus and methods for control of the second order temperature dependence of the frequency of a mechanical resonating structure are described. The second order temperature dependence of frequency of the mechanical resonating structure may be non-linear. Control may be provided by doping of a semiconductor layer of the mechanical resonating structure.

Abstract: A multilevel DC-DC converter includes a voltage source that provides a voltage Vout1 to at least one charge converter circuit and an output filter capacitor having an associated output voltage Vout2. The at least one charge converter circuit includes a transformer having at least one primary winding and at least two secondary windings, a primary and secondary circuit each having at least two switching elements, and a control unit which receives a control signal, such as but not limited to an envelope tracking signal, which represents a desired output voltage. The control unit is arranged to provide output control signals to the respective switching elements of the primary and secondary circuits to activate and deactivate the respective switching elements to obtain a desired output voltage Vout2. The multilevel DC-DC converter can be arranged to operate as a boost converter or as a buck-boost converter.

Abstract: The system may include a pixel array, a selector, a sampler, and a converter. The pixel array may generate output signals representing radiation incident upon the pixel array. The selector may select one of the output signals. The sampler may sample the selected output signal. The converter may generate a digital signal based upon the selected output signal. The sampler may include a charge integrator that compensates for parasitic capacitance of the selector by selecting a first feedback capacitance to obtain a first sample, and after obtaining the first sample, selecting a second feedback capacitance to obtain a second sample. The first feedback capacitance may be greater than the second feedback capacitance.

Abstract: Reducing distortions in a digital-to-analog converter is a challenge for circuit designers. For current steering digital-to-analog converters (DACs), a quad switching scheme has been used to remove code-dependent glitching which is otherwise present in dual switching schemes. However, due to various impairments in the circuit, e.g., mismatches in the transistors, some code-dependent distortions remain even when a quad switching scheme is implemented. To address this issue, the quad switching scheme can be randomized to improve dynamic linearity while relaxing driving circuitry design and power constraints. Advantageously, randomization reduces the code dependency of the distortions and makes the distortions appear more noise-like at the output of the DAC.

Abstract: Embodiments of the present invention may provide a circuit. The circuit may include a primary side, a secondary side, and an isolated energy transfer device electrically isolating the primary side and the secondary side. The primary side may include a first energy storage device coupled to a power source, a control system coupled to the first energy storage device for power, a second energy storage device, and a coupling system, coupled to the control system, to selectively couple the second energy storage device to the power source in a first phase and to selectively couple the second energy storage device to the primary side of the isolated energy transfer device during a second phase.

Abstract: An exemplary timing generator includes a coarse delay circuit configured to generate a coarse delayed rising edge signal and a coarse delayed falling edge signal from a reference timing signal; a fine delay circuit configured to generate a fine delayed rising edge signal from the coarse delayed rising edge signal and a fine delayed falling edge signal from the coarse delayed falling edge signal; an edge combiner configured to generate the timing signal based on the fine delayed rising edge signal and the fine delayed falling edge signal; and a masking circuit configured to generate a rising edge masking signal and a falling edge masking signal for controlling when the rising edges and the falling edges of the timing signal are generated.