Negative impedance circuit and corresponding device

An electronic device comprising:

• a circuit block exhibiting an input impedance;
• and
• a negative impedance circuit comprising:
• a differential circuit stage having a first input coupled to the circuit block, a second input and an output,
• a positive feedback path from the output of the differential circuit stage to the first input of the differential circuit stage, and
• a negative feedback path from the output of the differential circuit stage to the second input of the differential circuit stage, wherein:
• the negative feedback path comprises a first transistor, and a unitary gain path from the output of the differential circuit stage to the second input of the differential circuit stage, the unitary gain path coupled to ground via a reference impedance,
• the positive feedback path comprises a second transistor,
• the first transistor and the second transistor have respective control electrodes configured to be driven by the output of the differential circuit stage, the first transistor and the second transistor coupled in a current mirror arrangement, and
• the negative impedance circuit is configured to cause a negative impedance at the first input of the differential circuit stage that is configured to modify the input impedance of the circuit block.

A method comprising:

• driving a control node of a first transistor of a negative feedback path with an output of a differential circuit stage, wherein the negative feedback path is coupled from an output of a differential circuit stage to a second input of the differential circuit stage, and wherein the negative feedback path comprises a unitary gain path from the output of the differential circuit stage to the second input of the differential circuit stage, the unitary gain path coupled to ground via a reference impedance;
• a driving a control node of a second transistor of a positive feedback path with the output of the differential circuit stage, wherein the positive feedback path is coupled from the output of the differential circuit stage to a first input of the differential circuit stage, and wherein the first transistor and the second transistor are coupled in a current mirror arrangement;
• and
• generating a negative impedance at the first input of the differential circuit stage based on the driving the control nodes of the first and second transistors to modify an input impedance at an input of a circuit block, wherein the first input of the differential circuit stage is coupled to the input of the circuit block.