Analog Devices International Unlimited Company

Analog Devices Global

Analog Devices Global Unlimited Company

China University of Petroleum

Hanqing Wang

GuangYang Qu

Yimiao Zhao

Junbiao Ding

Shurong Gu

Rengui Luo

Yincai Tony Liu

Baotian Hao

Hengfang Mei

Dennis A Dempsey

Gerard Mora-Puchalt

Tony Yincai Liu

Li Wang

Yang Xia

John Jude O'Donnell

Liam Patrick Riordan

Zhou Zhou

Bing Hou

Yan Jin

Xuyang Guo

Mian Chen

José Carlos Conchell Añó

Yunhu Lu

Botao Lin

Leicheng Chen

Zejun Li

Tony Shi

An apparatus comprises an integrated circuit that includes an input to receive an electrical input signal from an electronic sensor, wherein the input signal includes a direct current (DC) offset and a varying signal component; a digital-to-analog converter (DAC) circuit configured to subtract the DC offset from the input signal; a programmable gain amplifier (PGA) operatively coupled to the DAC circuit, wherein the PGA circuit is configured to apply signal gain to the varying signal component of the input signal; and a measurement circuit configured to generate a measure of the varying signal component.

Devices and methods for smart sensor application

An apparatus comprises a load resistance connectable in series with the electronic sensor to form a series resistance of the load resistance and the internal impedance of the electronic sensor; an excitation circuit configured to apply a predetermined voltage to a circuit element; and a measurement circuit configured to: initiate applying the predetermined voltage to the series resistance and determining the series resistance; initiate applying the predetermined voltage to the load resistance and determining the load resistance; and calculate the internal impedance of the sensor using the determined series resistance and the load resistance, and provide the calculated internal impedance to a user or process.

Techniques for generating a diagnostic waveform for a sensor are provided. In an example, a control circuit for an electrochemical sensor can include power supply inputs configured to receive a supply voltage, a first signal generator configured to receive control information and to generate a first signal on a first output using the supply voltage and the control information, a second signal generator configured to receive the control information and to provide a second signal on a second output, using the supply voltage and the control information. An output voltage between the first output and the second output, in a diagnostic mode of operation of the control circuit, can include a periodic signal having a peak-to-peak voltage greater than the supply voltage.

Diagnostic waveform generator for a sensor

A modeling method is provided. The modeling method includes: extracting multiple pieces of logging data corresponding to a plurality of logging characteristic parameters at different drilling depths of a sample well, based on a logging information of the sample well; marking the different drilling depths based on a lost circulation information of the sample well to distinguish lost circulation points and non-lost circulation points; and classifying the lost circulation points and the non-lost circulation points by adopting a random forest algorithm, based on the plurality of logging characteristic parameters and the multiple pieces of marked logging data at the different drilling depths, to establish a plurality of corresponding relations between the logging characteristic parameters and a lost circulation or non-lost circulation result, so as to obtain a diagnosis model.

Modeling method and method for diagnosing lost circulation

A device and method for measuring the internal impedance of an electronic sensor uses configurable gain stages to selectively apply different excitation signals to the sensor under test in order to ensure adequate signal-to-noise ratio to provide accurate measurement of the internal impedance over a broader range of internal impedances than the prior art.

This disclosure describes techniques for selecting one of a plurality of modes in which to operate an amplifier. The techniques include configuring input routing circuitry, coupled to first and second inputs of the amplifier, based on the selected one of the plurality of modes; selectively applying a resistance to an output of the amplifier, using feedback routing circuitry, based on the selected one of the plurality of modes; and selectively applying one of a plurality of reference voltages, using reference voltage routing circuitry, coupled to the first and the second inputs of the amplifier, based on the selected one of the plurality of modes.

Amplifier configurable into multiple modes

Techniques for improving noise performance while processing signals received from an electrochemical sensor are provided. In an example, an interface circuit can include a first amplifier configured to provide a voltage to a counter electrode of an electrochemical sensor, a second amplifier configured to receive sensor information from a working electrode of the electrochemical sensor and to provide concentration information using the sensor information. In certain examples, an input of the first amplifier can be directly coupled to an input of the second amplifier to attenuate noise, of either the first amplifier or the second amplifier, within the concentration information provided by the second amplifier.

Sensor bias circuit for improved noise performance

Various examples are directed to a measurement system for measuring an electrical property of skin comprising an excitation circuit, a receiver circuit, and a sequencer circuit. The excitation circuit may generate a periodic excitation signal that, when provided to the skin, generates a response signal in the skin indicative of the electrical property. The sequencer circuit may be configured to activate the excitation circuit to provide the excitation signal to the skin. While the excitation circuit is activated to provide the excitation signal to the skin, the sequencer circuit may activate the receiver circuit to execute a first sample cycle to generate a first plurality of samples of the response signal. A first value for the electrical property of the skin may be determined based at least in part on the first plurality of samples of the response signal.

Low power measurement of skin electrical properties

A common mode reference circuit comprises a divider stage and an output stage. The divider stage includes a first n-channel field effect transistor and p-channel filed effect transistor (NFET/PFET) pair connected in series to a high supply voltage circuit node; and a second NFET/PFET pair connected in series to a low supply voltage circuit node. The output stage includes a first FET connected as a current mirror to a transistor of the first NFET/PFET pair; a second FET connected as a current mirror to a transistor of the second NFET/PFET pair; and a common mode reference output at a series connection from the first FET to the second FET.

Low power half-VDD generation circuit with high driving capability

A electrochemical or other sensor interface circuit architecture can deliver substantial DC offset bias to an electrochemical or other sensor separately or independently from delivering a time-varying AC excitation signal, which can then be provided with higher resolution, which, in turn, can allow better resolution of the measured response signal providing the impedance characteristic of sensor condition. For example, a differential time-varying AC excitation signal for the sensor condition characteristic can be delivered separately and independently from a differential stable (e.g., DC or other) bias signal, such as by using separate digital-to-analog converters (DACs), so that providing the more stable signal does not limit the resolution and accuracy of the time-varying signal, such as by using up the dynamic range of a single DAC.

Impedance characteristic circuit for electrochemical sensor

A capacitive gain amplifier circuit amplifies an input signal by a pair of differential amplifier circuits couples in series. The first differential amplifier circuit is reset during an autozero phase while disconnected from the second differential amplifier circuit, and the first and second differential amplifier circuits are connected together in series during a chop phase. A set of feedback capacitors is selectively switched in between respective outputs of the second differential amplifier circuit and respective inputs of the first differential amplifier circuit during the chop phase.

Fast settling capacitive gain amplifier circuit

A capacitive gain amplifier circuit includes two sets of Miller capacitors and two output stage differential amplifier circuits. A first set of Miller capacitors is used to compensate the first output stage differential amplifier circuit during a first phase that resets the first output stage differential amplifier circuit. The second set of Miller capacitors is used to compensate the first output stage differential amplifier circuit during a second phase that chops a signal being amplified. The second set of Miller capacitors is swapped from one polarity to an opposite polarity of the first output stage differential amplifier circuit during successive second phases. The second output stage differential amplifier circuit includes a set of inputs selectively coupled with the inputs of the first output stage differential amplifier circuit and a set of outputs selectively coupled with the outputs of the first output stage differential amplifier circuit during the second phase.

A multiple output, multiple impedance string digital-to-analog converter (DAC) circuit can provide a first output having a first resolution in response to a first digital input signal and a second output having a second resolution in response to a second digital input signal. A main impedance string and a secondary impedance string can be coupled using switching networks to provide a first DAC output. By coupling additional switches to the main impedance string and by sharing the main impedance string, a second DAC output can be realized.

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Beijing, China

Hanqing Wang