Differential current conveyor circuit, corresponding device, and method of operation thereof

A circuit, comprising:

• a plurality of cooperative stages, a respective cooperative stage comprising:
• a pair of transistors comprising a first transistor and a second transistor, wherein a current path of the first transistor is coupled in series with a current path of the second transistor, wherein the first transistor and the second transistor are coupled at an intermediate point between the pair of transistors, wherein the intermediate point comprises an input terminal of the respective cooperative stage, wherein the pair of transistors comprises control terminals capacitively coupled to the input terminal of the respective cooperative stage;
• a plurality of output branches configured to be driven by the pair of transistors, wherein the plurality of output branches are coupled at an output terminal of the circuit;
• a first coupling line coupling the control terminals of the first transistors of each of the plurality of cooperative stages;
• a second coupling line coupling the control terminals of the second transistors of each of the plurality of cooperative stages;
• a pair of current buffers comprising a first current buffer and a second current buffer, wherein an input of the first current buffer is coupled to a current path of the first transistor at a node opposite the intermediate point, wherein an input of the second current buffer is coupled to a current path of the second transistor at a node opposite the intermediate point;
• and
• a summation node coupled to outputs of the pair of current buffers, wherein an output of the summation node comprises the output terminal of the circuit;
• and
• a common bias stage comprising a further pair of transistors arranged with current paths in series and coupled at a further intermediate point between the further pair of transistors, wherein the further intermediate point comprises a further input terminal of the circuit, wherein control terminals of the further pair of transistors are couplable to the first coupling line and the second coupling line, respectively.

A device, comprising:

• a circuit, comprising:
• a plurality of cooperative stages, a respective cooperative stage comprising:
• a pair of transistors comprising a first transistor and a second transistor, wherein a current path of the first transistor is coupled in series with a current path of the second transistor, wherein the first transistor and the second transistor are coupled at an intermediate point between the pair of transistors, wherein the intermediate point comprises an input terminal of the respective cooperative stage, wherein the pair of transistors comprises control terminals capacitively coupled to the input terminal of the respective cooperative stage;
• a plurality of output branches driven by the pair of transistors, wherein the plurality of output branches are coupled at an output terminal of the circuit;
• a first coupling line coupling the control terminals of the first transistors of each of the plurality of cooperative stages;
• and
• a second coupling line coupling the control terminals of the second transistors of each of the plurality of cooperative stages;
• a common bias stage comprising a further pair of transistors arranged with current paths in series and coupled at a further intermediate point between the further pair of transistors, wherein the further intermediate point comprises a further input terminal of the circuit, wherein control terminals of the further pair of transistors are couplable to the first coupling line and the second coupling line, respectively;
• a first switch coupled between the control terminal of a first one of the further pair of transistors and the first coupling line;
• and
• a second switch coupled between the control terminal of a second one of the further pair of transistors and the second coupling line, wherein the first switch and the second switch are switchable between:
• a reset state of the circuit with the further pair of transistors coupled to the first coupling line and the second coupling line;
• and
• a sensing state of the circuit with the further pair of transistors decoupled from the first coupling line and the second coupling line;
• and
• a plurality of sensing capacitors coupled with the input terminals of the plurality of cooperative stages.

A method, comprising:

• providing a circuit, comprising:
• a plurality of cooperative stages, a respective cooperative stage comprising:
• a pair of transistors comprising a first transistor and a second transistor, wherein a current path of the first transistor is coupled in series with a current path of the second transistor, wherein the first transistor and the second transistor are coupled at an intermediate point between the pair of transistors, wherein the intermediate point comprises an input terminal of the respective cooperative stage, wherein the pair of transistors comprises control terminals capacitively coupled to the input terminal of the respective cooperative stage;
• a plurality of output branches driven by the pair of transistors, wherein the plurality of output branches are coupled at an output terminal of the circuit;
• a first coupling line coupling the control terminals of the first transistors of each of the plurality of cooperative stages;
• and
• a second coupling line coupling the control terminals of the second transistors of each of the plurality of cooperative stages;
• and
• a common bias stage comprising a further pair of transistors arranged with current paths in series and coupled at a further intermediate point between the further pair of transistors, wherein the further intermediate point comprises a further input terminal of the circuit, wherein control terminals of the further pair of transistors are couplable to the first coupling line and the second coupling line, respectively;
• entering a reset state of the circuit by turning on first and second switches, wherein the first switch is coupled between the control terminal of a first one of the further pair of transistors and the first coupling line, and the second switch is coupled between the control terminal of a second one of the further pair of transistors and the second coupling line;
• entering a sensing state by turning of the first and second switches;
• and
• sensing values of a plurality of sensing capacitors coupled with the input terminals of the plurality of cooperative stages by alternatively coupling and de-coupling the further pair of transistors in the common bias stage with respect to the first coupling line and the second coupling line in the plurality of cooperative stages.