Patent ID: 6137359
Filing Date: 2000-10-24
Classification: H03F

Abstract:
An amplifier circuit for connection to a voltage source and to first and second terminals of a load, comprising:a main current source, having a first signal terminal for connection to the first terminal of the load, a second signal terminal and a control terminal for connection to the voltage source, the main current source having a gain (G.sub.1);a first sensing resistor connected between the second signal terminal of the main current source and for connection to a reference voltage, the first sensing resistor having a resistance (R.sub.S1);an auxiliary current source, having a first signal terminal for connection to the first terminal of the load, a second signal terminal for connection to the reference voltage and a control terminal; anda second sensing resistor for connection between the second terminal of the load and the reference voltage, the second sensing resistor having a resistance (RS2); anda feedback circuit for connection to the second terminal of the load and connected to the control terminals of the main and auxiliary current sources for providing first and second feedback gains (K.sub.1, K.sub.2) to the first and second current sources, respectively;wherein G.sub.1 K.sub.1 R.sub.S1 is substantially greater than unity and wherein ##EQU24## lies between approximately 0.75 and approximately 4; wherein the elements in the feedback circuit are chosen such that the current produced by the auxiliary current source is substantially equal to a distorted portion of the current produced by the main current source so that the current produced by the auxiliary current source cancels out the distorted portion of the current produced by the main current source.