Patent ID: 6842075

Claim:
A circuit for biasing a first transistor having a control terminal, current-sink terminal, and current-source terminal and capable of operating at least from a first regulated power supply and a second power supply, the circuit comprising: a. a second transistor having a control terminal, current-sink terminal and current-source terminal, wherein the control terminal of the second transistor is connected to the control terminal of the first transistor in a current-mirror configuration, and wherein the current-source terminal of the second transistor is connected to a first terminal of the first regulated power supply; b. at least one resistor connected between the current-sink terminal of the second transistor and a second terminal of the first regulated power supply; c. a feedback circuit, including a non-inverting amplifier having a feedback transistor, and input and output ports, wherein the input port of the non-inverting amplifier is connected to the at least one resistor and the current-sink terminal of the second transistor; and wherein furthermore a control terminal of a feedback transistor is connected to the output port of the non-inverting amplifier, and a current-source terminal of the feedback transistor connected to the second transistor and the first transistor, with the current-sink terminal of the feedback transistor connected to the second terminal of the second power supply, whereby the non-inverting amplifier increases the gain of the feedback circuit so that the bias circuit is relatively insensitive to fluctuations In supply voltage or temperature.