Analog Devices,inc.

Analog Devices International Unlimited Company

Analog Devices Global

Corey Petersen

Gerard E Taylor

Stephen Robert Kosic

Allen R Barlow

Janet M Brunsilius

Hajime Shibata

Antonio J Montalvo

Trevor Clifford Caldwell

David Nelson Alldred

Carroll Clifton Speir

Eric Otte

Daniel Rey-Losada

Nevena Rakuljic

Jeffrey Paul Bray

Satishchandra G Rao

Kaustubh Pradeepkumar Mundhada

Vinoth Kumar

Madhusudan Rathi

Delay calibration for digital signal chains of SFCW systems is disclosed. An example calibration method includes receiving a burst with a test pulse, the burst having a duration of L clock cycles; receiving a trigger indicative of a time when the burst was transmitted; generating a digital signal indicative of the received burst; for each of L clock cycles, computing a moving average of a subset of digital samples and an amplitude for each average; identifying one moving average for which the computed amplitude is closest to an expected amplitude; identifying the clock cycle of the identified moving average; and updating at least one delay to be applied in digital signal processing of received bursts based on a difference between the trigger and the identified clock cycle. The delay may be used for selecting digital samples of the received signal that contain valid data for performing further data processing.

Delay calibration for a stepped frequency continuous wave digital signal chain

To address non-linearity, an on-chip linearization scheme is implemented along with an analog-to-digital converter (ADC) to measure and correct/tune for non-linearities and/or other non-idealities of the signal path having the ADC. The on-chip linearization scheme involves generating one or more test signals using an on-chip digital-to-analog converter (DAC) and providing the one or more test signals as input to the signal path to be linearized, and estimating non-linearity based on the one or more test signals and the output of the ADC. Test signals can include single-tone signals, multi-tone signals, and wideband signals spread over a range of frequencies. A time-delayed interleaving clocking scheme can be used to achieve a higher data rate for coefficient estimation without having to increase the sample rate of the ADC.

Signal path linearization

Delta-sigma modulators do not handle overload well, and often become unstable if the input goes beyond the full-scale range of the modulator. To provide overload protection, an improved technique embeds an overload detector in the delta sigma modulator. When an overload condition is detected, coefficient(s) of the delta sigma modulator is adjusted to accommodate for the overloaded input. The improved technique advantageously allows the delta sigma modulator to handle overload gracefully without reset, and offers greater dynamic range at reduced resolution. Furthermore, the coefficient(s) of the delta sigma modulator can be adjusted in such a way to ensure the noise transfer function is not affected.

Embedded overload protection in delta-sigma analog-to-digital converters

Apparatus and methods for ultrasound probes are provided. In certain implementations, a receive switch for an ultrasound probe includes a first field effect transistor (FET) and a second FET electrically connected in series between a first terminal and a second terminal with the FETs' sources connected to one another. The receive switch includes a positive threshold detection and control circuit for turning off the receive switch when a voltage of the first terminal is greater than a positive threshold voltage, and a negative threshold detection and control circuit for turning off the receive switch when the first terminal's voltage is less than a negative threshold voltage. The receive switch further includes a gate bias circuit that can bias the gates of the first and second FETs so as to turn on the receive switch when no positive or negative high voltage conditions are detected on the first terminal.

Apparatus and methods for ultrasound probes

A circuit can include an NMOS transistor having a drain and a source, a p-well containing the drain and the source, an n-well under the p-well, a circuit node, and a connection element connecting the n-well to the circuit node. The connection element can include a diode having an anode terminal connected to the circuit node and a cathode terminal connected to the n-well, a resistor having a first terminal connected to the circuit node and a second terminal connected to the n-well, a conductor directly connecting the n-well to the circuit node, or a well switch configured to connect the n-well to the circuit node during an enable phase of a switching signal and to electrically float the n-well during a non-enable phase of the switching signal. The diode can include a diode-connected transistor. The circuit node can be configured to receive a predetermined voltage having a magnitude equal to or greater than an upper supply voltage.

Dynamically driven deep n-well circuit

Apparatus and methods for ultrasound transmit switching are provided. In certain implementations, a transmit switch includes a bias polarity control circuit, a bias circuit, a first high voltage field effect transistor (HVFET), and a second HVFET. The sources of the first and second HVFETs are connected to one another at a source node, the gates of the first and second HVFETs are connected to one another at a gate node, and the drains of the first and second HVFETs are connected to an input terminal and an output terminal, respectively. The bias circuit and the bias polarity control circuit are each electrically connected between the source node and the gate node. The bias polarity control circuit can turn on or off the HVFETs by controlling a polarity of a bias voltage across the bias circuit, such as by controlling a direction of current flow through the bias circuit.

Apparatus and methods for ultrasound transmit switching

An amplifier with a single-input class-AB output stage comprises an input stage providing a signal to an output stage. The output stage comprises a current-splitting stage having a bias current and providing at least two intermediate output currents, and a drive stage receiving the two intermediate output currents and driving an output signal having a positive side and a negative side.

Single input class-AB rail-to-rail output stage

A circuit includes an NMOS transistor having a drain and a source, a p-well containing the drain and the source, an n-well under the p-well, and a first well switch configured to selectively connect the n-well to a predetermined voltage in response to an enable phase of a first switching signal. The first well switch can be configured to connect the n-well to the predetermined voltage during the enable phase of the first switching signal and to electrically float the n-well during a non-enable phase of the first switching signal.

Dynamically-driven deep n-well circuit

Receiver embodiments are disclosed that can process a wide range of transmission bandwidths over a wide range of transmission frequencies and provide reduced converter sampling rates, filter bandwidths, and filter tuning ranges and enhanced signal-to-noise performance. They convert transmission signals with quadrature local oscillator signals whose frequencies are commanded to be a selected transmission frequency when a selected transmission bandwidth is above a predetermined bandwidth threshold and are commanded to be offset from the selected transmission frequency by an intermediate frequency that is at least one half of the selected transmission bandwidth when the selected transmission bandwidth is below the bandwidth threshold.

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Poway, CA, United States of America

Corey Petersen