Analog Devices,inc.

Analog Devices International Unlimited Company

David James Plourde

Quan Wan

George Reitsma

Andreas Koch

Alasdair Gordon Alexander

Raymond Thomas Perry

Matthew N Duff

Greg L Disanto

Paul A Perrault

George Pieter Reitsma

Various examples are directed to a frequency-compensated amplifier circuit comprising a first multi-stage amplifier comprising a first amplifier input node, a first amplifier output node, and a first amplifier intermediate node. A first feedback path between the first amplifier input node and the first amplifier output node comprises a feedback resistance. A second feedback path between the first amplifier output node and the first amplifier intermediate node comprises a first capacitor and a portion of the feedback resistance. A first switch circuit may be electrically coupled to the first capacitor and to the feedback resistance. The first switch circuit may have a first state in which the first capacitor is coupled to a first tap point of the feedback resistance and the portion of the feedback resistance has a first value. The first switch circuit may also have a second state in which the first capacitor is coupled to a second tap point of the feedback resistance and the portion of the feedback resistance has a second value different than the first value.

Amplifier compensation circuits and methods

A system for processing a signal in a signal chain having decentralized embedded power management of components of the signal chain includes an input circuit to generate a measurement signal responsive to a stimulus, where the measurement signal is indicative of a characteristic of the stimulus. The system additionally includes a signal converter circuit coupled to the input circuit to convert the measurement signal to a digital signal according to a timing condition for capturing a sample of the measurement signal. The signal converter includes a control circuit to provide electrical power to the input circuit based on the timing condition and a sampling circuit to capture the sample of the measurement signal responsive to an indicator signal generated by the sensor circuit.

Signal chain with embedded power management

Various examples are directed to amplifier circuits and methods for operating amplifier circuits. The amplifier circuit may comprise a first amplifier stage. The first amplifier stage comprises a first amplifier, a first feedback resistance, a second amplifier, a second feedback resistance, and a gain resistance. A first current source may be electrically coupled to provide a first current across the gain resistance in a first direction. A second current source may be electrically coupled to provide a second current across the gain resistance in a second direction opposite to the first direction.

Amplifier input offset compensation

Apparatus and methods reduce the likelihood of amplifier saturation due to propagated DC offsets, and reduce the recover from saturated stated when such saturation occurs. Advantageously, these attributes are beneficial for monitoring of bioelectric signals. A circuit uses an instrumentation amplifier connected as a high pass filter to attenuate large DC offsets and amplify small signals. The circuit can include an instrumentation amplifier electrically coupled with a first feedback circuit including at least one resistor and a second feedback circuit including an op-amp. The feedback circuit can also include a low-pass filter. The op-amp in the second feedback circuit can be configured as a non-inverting amplifier, an inverting amplifier, and/or an integrator circuit. Alternatively, the circuit can include an instrumentation amplifier with one feedback circuit including at least one resistor, and a coupling capacitor electrically coupled with a reference voltage.

Apparatus and method for amplification with high front-end gain in the presence of large DC offsets

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Pembroke, NH, United States of America

David James Plourde