Patent ID: 9071209
Filing Date: 2015-06-30
Classification: G01N,G01R

Abstract:
1. An apparatus for sensing currents conducted via an electrode, the apparatus comprising: an operational amplifier including a first input terminal, a second input terminal, and an output terminal, the first input terminal being configured to electrically couple with the electrode; a feedback circuit coupling the output terminal of the operational amplifier to the first input terminal, the feedback circuit comprising a plurality of transistor devices configured to generate a feedback current based on a voltage value of the output terminal, and further configured to provide the feedback current to the first input terminal, wherein the plurality of transistor devices comprises a first set of transistor devices configured to generate a positive feedback current in response to the voltage value of the output terminal being positive, and wherein the plurality of transistor devices further comprises a second set of transistor devices configured to generate a negative feedback current in response to the voltage value of the output terminal being negative; and a voltage source coupled to the second input terminal and configured to maintain a substantially constant voltage at the second input terminal.