US 12,553,858 B2 · Potentiostat with offset calibration

Abstract

A rail-to-rail potentiostat may require an offset current in order to support a bidirectional work electrode current at a work electrode. This offset current may improve measurements of the work electrode current made a dual-slope analog-to-digital converter, especially when the work electrode current is small, but can also lead to inaccuracies (e.g., due to a temperature coefficient) if it is not properly calibrated. Accordingly, bidirectional potentiostat is disclosed that can be configured in a normal configuration for measurement of a work electrode current or a calibration configuration for measurement (i.e., calibration) of an offset current. The reconfigurability allows calibrations to be taken as needed, on a schedule, or as specified by a user. The reconfigurability can also allow for maintaining a work electrode voltage and a work electrode current during calibration so that an electrochemical experiment using a cell coupled to the bidirectional potentiostat is unaffected by the calibration.

Claims20

Dependent claims

A bidirectional potentiostat, comprising:

a sensing and digitizing portion configured to generate a digital signal corresponding to a work electrode current of a work electrode;
a current-conveyer portion coupled between the sensing and digitizing portion and a front-end portion;
and
the front-end portion including a first feedback amplifier coupled to the work electrode and a replica feedback amplifier not coupled to the work electrode, wherein:
in a normal configuration, the first feedback amplifier is coupled to the current-conveyer portion and the replica feedback amplifier is decoupled from the current-conveyer portion;
and
in a calibration configuration, the first feedback amplifier is decoupled from the current-conveyer portion and the replica feedback amplifier is coupled to the current-conveyer portion.

4 more elements

A cell measurement system, comprising:

an electrochemical cell having a work electrode;
and
a bidirectional potentiostat, including:
a front-end portion that includes a first feedback amplifier coupled to the work electrode and a replica feedback amplifier not coupled to the work electrode, wherein:
in a normal configuration, the first feedback amplifier is coupled to a sensing and digitizing portion and the replica feedback amplifier is decoupled from the sensing and digitizing portion;
and
in a calibration configuration, the first feedback amplifier is decoupled from the sensing and digitizing portion and the replica feedback amplifier is coupled to the sensing and digitizing portion;
an offset portion that includes an offset current source and a replica offset current source, wherein:
in the normal configuration, the offset current source is coupled to the work electrode and the first feedback amplifier, and the replica offset current source is coupled to the replica feedback amplifier;
and
in the calibration configuration, the offset current source is coupled to the replica feedback amplifier, and the replica offset current source is coupled to the work electrode and the first feedback amplifier;
and
a current-conveyer portion coupled between the front-end portion and the sensing and digitizing portion, the current-conveyer portion including a first current mirror and a second current mirror.

10 more elements

Dependencies are inferred from the claim text.

Potentiostat with offset calibration

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Potentiostat with offset calibration

Life of this patent

Abstract

Claims20