Circuit for Integrating Currents from High-Density Sensors

A circuit having a circuit input adapted to receive an input current, the circuit having a first reference input adapted to receive a first reference voltage and having a second reference input adapted to receive a second reference voltage, the circuit comprising:

• a first stage integrator including a first input coupled to the circuit input, a second input coupled to the first reference input, a third input coupled to the second reference input and an output coupled to the first input of the first stage integrator via a first feedback path;
• a transfer switch including a first terminal coupled to the first input of the first stage integrator and including a second terminal;
• and
• a second stage integrator including a first input coupled to the second terminal of the transfer switch, a second input coupled to the first reference input, and an output coupled to the first input of the second stage integrator by a third feedback path.

A circuit having a circuit input adapted to receive an input current, the circuit having a first reference input adapted to receive a first reference voltage and having a second reference input adapted to receive a second reference voltage, the circuit comprising:

• a first amplifier including a first input coupled to the circuit input, a second input coupled to the first reference input and including an output;
• a first switch including a first terminal coupled to the output of the first amplifier and including a second terminal;
• a first feedback capacitor including a first terminal coupled to the first input of the first amplifier and a second terminal coupled to the second terminal of the first switch;
• a second switch including a first terminal coupled to the second terminal of the first feedback capacitor and a second terminal coupled to the second reference input;
• a transfer switch including a first terminal coupled to the first input of the first amplifier and including a second terminal;
• a second amplifier including a first input coupled to the second terminal of the transfer switch, a second input coupled to the first reference input and including an output;
• and
• a second feedback capacitor including a first terminal coupled to the first input of the second amplifier and a second terminal coupled to the output of the second amplifier.