Impedance shifting circuit and signal sensing circuit

摘要

A signal sensing circuit is provided. The signal sensing circuit comprises a first current-to-voltage circuit, a second current-to-voltage circuit and an impedance shifting circuit. The first current-to-voltage circuit converts a first input current into a first voltage that is directly proportional to a first impedance. The second current-to-voltage circuit converts a second input current into a second voltage that is directly proportional to a second impedance. The impedance shifting circuit generates a third voltage according to the first voltage, wherein the first impedance/the second impedance=K(first voltage/third voltage), where K is a real number.

主权项

1. An impedance sifting circuit, comprising:
a first integrated circuit, including:
a first input resistor for receiving a first voltage;a first inverting closed-loop amplifier, including a first positive input, a first negative input and a first output, wherein the first output forming a first closed loop through a first reference resistor coupled to the first negative input and the first negative input receiving a first voltage input via the first input resistor, wherein the first input resistor and the first reference resistor are designed to have the same impedance;a second input resistor coupled to the first output; anda first external pin coupled to the first output via the second input resistor; and a second integrated circuit, including:
a second external pin electrically coupled to the first external pin outside the second integrated circuit; anda second inverting closed-loop amplifier, including a second positive input, a second negative input and a second output, wherein the second output forming a second closed loop through a second reference resistor coupled to the second negative input, and the second negative input coupled to the second input resistor via the second external pin, wherein the second input resistor and the second reference resistor are designed to have the same impedance.