US 11,808,729 B2
Interface circuit for an electrochemical sensor
Yonghong Tao, Singapore (SG)
Assigned to EM MICROELECTRONIC-MARIN SA, Marin (CH)
Filed by EM MICROELECTRONIC-MARIN SA, Marin (CH)
Filed on Apr. 27, 2020, as Appl. No. 16/858,987.
Claims priority of application No. 19174802 (EP), filed on May 16, 2019.
Prior Publication US 2020/0363368 A1, Nov. 19, 2020
Int. Cl. G01N 27/327 (2006.01); G01N 27/404 (2006.01); A61B 5/145 (2006.01); G01N 33/53 (2006.01)
CPC G01N 27/4045 (2013.01) [A61B 5/14532 (2013.01); G01N 27/3273 (2013.01); G01N 33/53 (2013.01)] 14 Claims
OG exemplary drawing
 
1. A sensor interface circuit for an amperometric electrochemical sensor, the sensor interface circuit comprising:
a current-to-voltage converter connected to a first terminal of the amperometric electrochemical sensor for converting an electric current through the amperometric electrochemical sensor to a voltage at an output terminal of the current-to-voltage converter,
a first amplifier connected between a second terminal and a third terminal of the amperometric electrochemical sensor for maintaining a substantially fixed voltage difference between the first and second terminals of the amperometric electrochemical sensor, the first amplifier comprising:
a first portion that includes a first low-side supply terminal and a first high-side supply terminal;
a second portion, different from the first portion, that includes a second low-side supply terminal and a second high-side supply terminal;
a first amplifier non-inverting input connected to the first portion; and
a first amplifier inverting input connected to the first portion;
a power supply for powering the current-to-voltage converter and for powering the first portion of the first amplifier, and
a negative voltage converter configured to power the second portion of the first amplifier through the second low-side supply terminal of the second portion, while the second high-side supply terminal of the second portion of the first amplifier is directly or indirectly connected to the power supply,
wherein a high-side output terminal of the power supply is directly or indirectly connected to the first high-side supply terminal of the first portion of the first amplifier for powering the first portion of the first amplifier,
a low-side output terminal of the power supply is connected to the first low-side supply terminal of the first portion of the first amplifier,
the first portion comprises input stage components of the first amplifier, while the second portion comprises output stage components of the first amplifier,
the first low-side supply terminal of the first portion is configured to be at zero volts based on being connected to the low-side output terminal of the power supply, and
the second low-side supply terminal of the second portion is configured to be at a negative voltage based on being connected to the negative voltage converter.