Abstract: A signal readout circuit for amperometric sensor for reading a readout signal of a sensor includes an amplifier, a first transistor, a second transistor, and a first resistor. A negative input end of the amplifier receives an input voltage, and a positive input end of the amplifier is connected to a reference electrode of the sensor. Gates of the first transistor and the second transistor are connected to an output end of the amplifier, a drain of the first transistor is connected to a counter electrode of the sensor, and a drain of the second transistor is connected to the first resistor.

Abstract: A signal readout circuit for amperometric sensor for reading a readout signal of a sensor includes an amplifier, a first transistor, a second transistor, and a first resistor. A negative input end of the amplifier receives an input voltage, and a positive input end of the amplifier is connected to a reference electrode of the sensor. Gates of the first transistor and the second transistor are connected to an output end of the amplifier, a drain of the first transistor is connected to a counter electrode of the sensor, and a drain of the second transistor is connected to the first resistor.

Abstract: An electronic circuit for ion sensor with the body effect reduction includes a bridge-type floating source circuit provided with an input terminal, an output terminal reflecting the change in the potential dependent on ion concentration, and an ion-sensitive field effect transistor (ISFET) wherein one terminal of the ISFET is coupled with the output terminal; a current mirror for providing a current to the bridge-type circuit; a third transistor for receiving the operating current provided by the current mirror, identical to the current provided to the ISFET; a differential amplifying circuit, wherein one input terminal of the amplifying circuit is input with a reference voltage, and the other input terminal is coupled with the output of the bridge-type readout circuit; and a third amplifier to generate a differential output voltage compensated for the body effect, temperature and time drift effects.

Abstract: An electronic circuit for ion sensor with the body effect reduction includes a bridge-type floating source circuit provided with an input terminal, an output terminal reflecting the change in the potential dependent on ion concentration, and an ion-sensitive field effect transistor (ISFET) wherein one terminal of the ISFET is coupled with the output terminal; a current mirror for providing a current to the bridge-type circuit; a third transistor for receiving the operating current provided by the current mirror, identical to the current provided to the ISFET; a differential amplifying circuit, wherein one input terminal of the amplifying circuit is input with a reference voltage, and the other input terminal is coupled with the output of the bridge-type readout circuit; and a third amplifier to generate a differential output voltage compensated for the body effect, temperature and time drift effects.

Abstract: An ion sening circuit comprises a bridge sensing circuit and a differential amplifying circuit. The bridge sensing circuit detects the ion concentration of the solution in the operation mode of constant voltage and constant current. The differential amplifying circuit compares the output of the bridge sensing circuit and a floating reference voltage, thereby the delivered voltage to the bridge sensing circuit, such that the opeation mode of constant voltage and constant current is formed accordingly. The main features of the disclosed circuit are that it grounds the reference electrode and floats the source terminal. The drawbacks of not being manufactured with intergrated circuits by CMOS technology and low benefits when applied to sensor arrays are avoided by the disclosed circuit.

Abstract: An ion sening circuit comprises a bridge sensing circuit and a differential amplifying circuit. The bridge sensing circuit detects the ion concentration of the solution in the operation mode of constant voltage and constant current. The differential amplifying circuit compares the output of the bridge sensing circuit and a floating reference voltage, thereby the delivered voltage to the bridge sensing circuit, such that the opeation mode of constant voltage and constant current is formed accordingly. The main features of the disclosed circuit are that it grounds the reference electrode and floats the source terminal. The drawbacks of not being manufactured with intergrated circuits by CMOS technology and low benefits when applied to sensor arrays are avoided by the disclosed circuit.