Biasing of an ionic current sensor

A sensing cell, comprising:

• an ionic current sensor;
• an integrating capacitor;
• a sense transistor coupled between the integrating capacitor and the ionic current sensor;
• and
• an amplifier coupled to provide a reference voltage to bias the ionic current sensor, wherein the amplifier comprises:
• a first transistor coupled to receive a bias voltage;
• and
• a second transistor coupled to the first transistor to provide the reference voltage to the ionic current sensor and coupled between a source of the sense transistor and the gate of the sense transistor.

A complementary metal-oxide-semiconductor (CMOS) ionic current sensor array, comprising:

• a master bias generator configured to generate a bias voltage in response to a master reference voltage;
• and
• a plurality of sensing cells, wherein each sensing cell of the plurality of sensing cells includes:
• a bias voltage node coupled to the master bias generator;
• an ionic current sensor;
• an integrating capacitor;
• a sense field effect transistor (FET) having a drain coupled to integrating capacitor and a source coupled to the ionic current sensor;
• and
• an amplifier coupled to provide a reference voltage to bias the ionic current sensor, wherein the amplifier comprises:
• a first FET coupled to the bias voltage node to receive the bias voltage;
• and
• a second FET coupled to the first FET to provide the reference voltage to the ionic current sensor, wherein the second FET comprises a drain coupled to a gate of the sense FET, a source coupled to a common reference, and a gate coupled to the source of the sense FET, wherein the reference voltage is substantially equal to the master reference voltage.