Cirrus Logic Inc.

Dale Brummel

Rahul Singh

John L Melanson

Prashanth Drakshapalli

Edwin De Angel

Stephen Timothy Hodapp

Jean Charles Pina

Prashanth Drakshappalli

Hang Liu

Robert Leon Gorsegner

A system may include a first voltage reference for generating a first voltage for operating a circuit, a second voltage reference having a higher precision than the first voltage reference, and a controller. The controller may be configured to determine a presence or an absence of a condition for calibrating the first voltage reference. The controller may also be configured to, responsive to the presence of the condition, enable the second voltage reference to generate a second voltage for calibrating the first voltage reference. The controller may further be configured to, responsive to the absence of the condition, disable the second voltage reference.

Systems and methods for providing an auto-calibrated voltage reference

A low power analog-to-digital converter configured to sense sensor signals may include a loop filter and a feedback digital-to-analog converter. The loop filter may have a loop filter input configured to receive an input current signal from a sensor and generate an output signal responsive to the input current signal. The feedback digital-to-analog converter may have a feedback output configured to generate a current-mode or charge-mode feedback output signal responsive to the output signal, the feedback output coupled to the loop filter input in order to combine the input current signal and the feedback output signal at the input.

Low power analog-to-digital converter for sensing geophone signals

A low power analog-to-digital converter (ADC) may sense current output of a geophone instead of voltage. The output of the geophone may be terminated through a resistor into a virtual ground of an integrator, which may be located inside a current mode delta-sigma analog-to-digital converter. The integrator may have a current mode or a charge mode feedback. Thus, the geophone may experience constant or substantially constant impedance terminated into a virtual ground. This approach may eliminate an instrumentation amplifier from a geophone sensing circuit, while still allowing for accurate sensing of geophone signals. The instrumentation amplifier is a major current consumer from the signal path, so its elimination may significantly reduce power consumption. The instrumentation amplifier may be eliminated, at least in part because of the provision of the resistance into a virtual ground of an integrator of the delta-sigma ADC.

A power measurement and calibration system provides power and line frequency measurements by using a bandpass filter having complex voltage and current outputs from which real and imaginary power components can be determined. Calibration of the filter may be omitted if a complex wavelet filter is used to implement the bandpass filter and a determination of line frequency can also be provided for downstream use. A processor receiving data from the output of the filter can compute real and imaginary power, power factor and the line frequency. The filter may be implemented by a processor executing program instructions, or a digital circuit implementing the filter and optionally a CORDIC rotator for computing the current-to-voltage phase relationship can provide input to the processor for power measurement and calibration of the sample rate to line frequency relationship and for other uses.

Growing community of inventors

Spicewood, TX, United States of America

Dale Brummel