CPC A61B 5/242 (2021.01) [A61B 5/7203 (2013.01); A61B 5/725 (2013.01); G01R 33/0023 (2013.01); G01R 33/098 (2013.01); A61B 2562/0223 (2013.01)] | 19 Claims |
1. A biomagnetism sensing system comprising:
a magnetic sensor comprising a plurality of sensor elements arranged in a full Wheatstone bridge configuration;
a differential amplifier configured to receive differential input signals from the magnetic sensor and generate an amplified measurement signal from the received differential input signals;
a low pass filter configured to remove high frequency components from the amplified measurement signal to provide a filtered signal;
a microcontroller configured to receive and process the filtered signal and generate an output signal; and
an input buffer amplifier stage connected between the magnetic sensor and the differential amplifier;
wherein the differential amplifier includes a common-mode feedback circuit configured to eliminate a common-mode current component from the differential input signals;
wherein the input buffer amplifier stage comprises:
a pair of operational amplifiers, each operational amplifier configured as a buffer amplifier for a respective one of the differential input signals, and
a chopper-stabilized input provided by an input chopper switch connected between the differential input signals and configured to modulate the differential input signals.
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