Cirrus Logic Inc.

Murata Manufacturing Co., Ltd.

Psemi Corporation

Vivek Saraf

Axel Thomsen

Timothy Joseph Dupuis

Vishnu Shankar Srinivasan

John Christopher Tucker

Ravi Kishore Kummaraguntla

James Thomas Deas

Ian Johnson Smith

Vishnu Srinivasan

Novel integrated circuit environmental and temperature sensors in combination with measurement circuitry fully integrated as part of an ASIC die, which may be co-packaged with a pressure sensor integrated circuit to create a compact yet sensitive environment monitoring product. Embodiments may include one or more integrated local heating elements and control circuitry that are power supply independent, make efficient use of battery power, include an accurate in-built temperature detection capability, and provide digital close-loop control of the heating elements.

Compact humidity and pressure sensor with temperature control

Circuits and methods for extending the linear range of IC-based environmental sensors. The IC-based environmental sensors may sense environmental characteristic such as humidity levels, the presence and/or concentration of specific chemicals, and/or the presence and/or concentration of specific biological molecules. The linearity of an environmental sensor can be extended by heating the sensor within a range of non-linear operation to artificially induce the sensor to operate within its linear range, and then accurately measuring, either directly or indirectly, the temperature rise caused by such heating. A correction factor is then determined based on the measured temperature rise that is combined with measurements from the sensor while operating within its non-linear range in order to generate an accurate estimate of an actual environmental characteristic.

High linear range humidity sensor

A bias circuit for a capacitive sensor may include a variable impedance element coupled to a capacitor of the capacitive sensor wherein an impedance of the variable impedance element is varied in accordance with a temperature associated with the bias circuit and an active feedback circuit coupled between the variable impedance element and an output of a processing circuit for processing a signal generated by the capacitive sensor and configured to drive the variable impedance element to force a direct-current (DC) voltage level of an output of the capacitive sensor to a desired voltage.

Active bias of microphone with variable bias resistance

The present disclosure relates to a protection system for protecting a MEMS transducer of a MEMS device from electrostatic capture, wherein the MEMS transducer is operable in a normal-sensitivity, mode and in a reduced-sensitivity mode. The protection system comprises: an overload detector for detecting an overload condition arising as a result of an excessive sound pressure level at the MEMS transducer; a signal estimator configured to generate an estimate of a sound pressure level at the MEMS transducer; and a controller configured, in response to detection by the overload detector of an overload condition, to: disable an output of the MEMS transducer; and after a delay of a first predetermined period of time: cause the MEMS transducer to operate in the reduced-sensitivity mode; enable the output of the MEMS transducer; and cause the MEMS transducer to return to the normal-sensitivity mode if the estimate of the sound pressure level generated by the signal estimator while the MEMS transducer is operating in the reduced-sensitivity mode is below a safe sound pressure level threshold for a second predetermined period of time.

MEMS devices

Input impedance biasing may be improved with an ultra-high-input-impedance biasing circuit having low temperature variation. The impedance biasing circuit may include a first transistor coupled to a first power supply and a second transistor coupled to a second power supply. A gate of the first transistor may be coupled to a gate of the second transistor at an intermediate bias node. The first transistor and the second transistor may provide a selected DC impedance at the intermediate bias node. The impedance may be used to provide low-pass and or high-pass filtering of audio signals and/or noise.

Growing community of inventors

Austin, TX, United States of America

Vivek Saraf