US 12,419,559 B2
Sensor readout circuitry, a biopotential signal sensor, a neural probe, and a method for readout of an analog sensor input signal
Shiwei Wang, Leuven (BE); and Marco Ballini, Leuven (BE)
Assigned to IMEC VZW, Leuven (BE)
Filed by IMEC VZW, Leuven (BE)
Filed on Mar. 14, 2022, as Appl. No. 17/693,907.
Claims priority of application No. 21162839 (EP), filed on Mar. 16, 2021.
Prior Publication US 2022/0296142 A1, Sep. 22, 2022
Int. Cl. A61B 5/24 (2021.01); A61B 5/00 (2006.01); A61N 1/05 (2006.01)
CPC A61B 5/24 (2021.01) [A61B 5/0031 (2013.01); A61B 5/6868 (2013.01); A61N 1/0529 (2013.01)] 14 Claims
OG exemplary drawing
 
1. A sensor readout circuitry comprising:
a delta-sigma modulator for converting an analog sensor input signal to a digital signal;
an input stage for receiving the analog sensor input signal, wherein the input stage comprises a transconductance amplifier comprising a pair of input transistors and a source degeneration resistor, a current mirror, and current sources, wherein the transconductance amplifier and the current mirror incorporate a flipped voltage follower, wherein a feedback signal from a digital-to-analog converter, DAC, of the delta-sigma modulator is received across the source degeneration resistor such that subtraction between the analog sensor input signal and the feedback signal is performed in the transconductance amplifier and mirrored by the current mirror to an output of the input stage;
wherein the transconductance amplifier comprises a first chopper between an input terminal for receiving the analog sensor input signal and an input transistor of the pair of input transistors for upmodulating the analog sensor input signal;
wherein the transconductance amplifier comprises a second chopper between the input transistor and the source degeneration resistor such that the analog sensor input signal is in baseband at a node in which the feedback signal is received;
wherein the transconductance amplifier comprises a third chopper before a connection of the transconductance amplifier to shared gates of the current mirror such that signals in the current mirror are in baseband;
whereby a chopping loop between the first, second and third choppers is formed including the input transistor and the current sources.