US 12,016,692 B2
Sensor readout circuit for a biomagnetism measurement system
Hadi Heidari, Glasgow (GB); and Siming Zuo, Glasgow (GB)
Assigned to The University Court of the University of Glasgow, Glasgow (GB)
Filed by The University Court of the University of Glasgow, Glasgow (GB)
Filed on Jul. 19, 2021, as Appl. No. 17/379,702.
Prior Publication US 2023/0012505 A1, Jan. 19, 2023
Int. Cl. A61B 5/242 (2021.01); A61B 5/00 (2006.01); G01R 33/00 (2006.01); G01R 33/09 (2006.01)
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
OG exemplary drawing
 
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.