Abstract: Consistent with the present invention, there is provided a circuit for extracting a common mode voltage of an input signal. The device may include an operational amplifier having an output, at least one negative input and at least one positive input, a first transistor, and a second transistor. A terminal of the first transistor may be coupled to the output of the operational amplifier. A terminal of the second transistor may be coupled to a terminal of the first transistor and the at least one positive input of the operational amplifier to create a negative feedback loop. The device may further include a common mode output, wherein the negative feedback loop extracts the common mode voltage of the input signal, the common mode voltage of the input signal being output at the common mode output. The device consistent with the present invention may provide the common mode voltage of the input signal without using any resistors, and while only occupying a small die area.

Abstract: Consistent with the present invention, there is provided a circuit for extracting a common mode voltage of an input signal. The device may include an operational amplifier having an output, at least one negative input and at least one positive input, a first transistor, and a second transistor. A terminal of the first transistor may be coupled to the output of the operational amplifier. A terminal of the second transistor may be coupled to a terminal of the first transistor and the at least one positive input of the operational amplifier to create a negative feedback loop. The device may further include a common mode output, wherein the negative feedback loop extracts the common mode voltage of the input signal, the common mode voltage of the input signal being output at the common mode output. The device consistent with the present invention may provide the common mode voltage of the input signal without using any resistors, and while only occupying a small die area.