Multichannel ion sensitive field effect transistor (ISFET) sensor readout circuit with compensation function

Abstract

The invention discloses a multichannel ion sensitive field effect transistor (ISFET) sensor array readout circuit with a compensation function. The readout circuit is used for detecting the ion concentration of a solution to be detected, the readout circuit comprises a plurality of ISFET sensor readout circuits, each ISFET sensor readout circuit forms a detection channel, each ISFET sensor readout circuit has a compensating port for receiving compensation signals provided by an external system to modify non ideal characteristics of ISFET sensors. The readout circuit adopts a multichannel detection mode, a plurality of parameters of the ISFET array sensors can be rapidly detected, parallel or serial output can be carried out by the detection mode according to the need of the system.

Description

technical field [0001] The invention belongs to the technical field of ion-sensitive field effect transistors (ISFETs), and relates to ISFET sensor readout circuits, ISFET signal processing and compensation control, in particular to a multi-channel ISFET sensor readout circuit with compensation functions. technical background [0002] Ion-sensitive field-effect transistor (ISFET) has a similar structure to metal oxide semiconductor MOSFET (Metal Oxide Silicon Field Effect Transistor), except that the gate of MOSFET is replaced by solution and ion-sensitive film, which passes through different sensitive film materials on the gate. It reacts directly with the ions in the solution to be tested, and then can be used to determine the ion concentration to detect multiple biochemical indicators. It has the dual characteristics of both electrochemical and MOSFET. Compared with traditional ion-selective electrodes, ISFET has the advantages of small size, high sensitivity, fast respon...

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Problems solved by technology

[0004] Since the reference electrode produced by the interaction between the quasi-reference electrode and the solution is unstable, and the electrical characteristics of the ISFET are sensitive to temperature, such as the sensitive film-solution interface potential will change with the temperature, and the threshold voltage of the ISFET will also change with the temperature. The pH value of the electrolyte will also change with the temperature. The traditional ISFET sensor readout circuit adopts a direct coupling amplification method. While amplifying the signal, the readout circuit also amplifies the offset and temperature drift accordingly.

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