CHOPPER-STABILIZED INSTRUMENTATION AMPLIFIER
First Claim
1. An electrical circuit comprising:
- a physiological sensor configured to generate an input signal;
a first modulator configured to modulate the input signal to produce a modulated signal;
an amplifier configured to amplify the modulated signal to produce an amplified signal;
a first demodulator configured to demodulate the amplified signal to produce an output signal;
a second modulator configured to modulate the output signal to produce a modulated output signal; and
a feedback path between an output of the second modulator and an input of the amplifier.
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Accused Products
Abstract
This disclosure describes a chopper stabilized instrumentation amplifier. The amplifier is configured to achieve stable measurements at low frequency with very low power consumption. The instrumentation amplifier uses a differential architecture and a mixer amplifier to substantially eliminate noise and offset from an output signal produced by the amplifier. Dynamic limitations, i.e., glitching, that result from chopper stabilization at low power are substantially eliminated through a combination of chopping at low impedance nodes within the mixer amplifier and feedback. The signal path of the amplifier operates as a continuous time system, providing minimal aliasing of noise or external signals entering the signal pathway at the chop frequency or its harmonics. The amplifier can be used in a low power system, such as an implantable medical device, to provide a stable, low-noise output signal.
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Citations
20 Claims
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1. An electrical circuit comprising:
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a physiological sensor configured to generate an input signal; a first modulator configured to modulate the input signal to produce a modulated signal; an amplifier configured to amplify the modulated signal to produce an amplified signal; a first demodulator configured to demodulate the amplified signal to produce an output signal; a second modulator configured to modulate the output signal to produce a modulated output signal; and a feedback path between an output of the second modulator and an input of the amplifier. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method comprising:
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generating an input signal with a physiological sensor; modulating the input signal to produce a modulated input signal; amplifying the modulated input signal with an amplifier to produce an amplified signal; demodulating the amplified signal to produce an output signal; modulating an amplitude of the output signal to produce a modulated output signal; and applying the modulated output signal to the modulated input signal via a feedback path to an input of the amplifier. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19)
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20. An implantable medical device comprising:
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means for generating an input signal with a physiological sensor; means for modulating the input signal to produce a modulated input signal; means for amplifying the modulated input signal with an amplifier to produce an amplified signal; means for demodulating the amplified signal to produce an output signal; means for modulating an amplitude of the output signal to produce a modulated output signal; and means for applying the modulated output signal to the modulated input signal via a feedback path to an input of the amplifier.
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Specification