Control circuit for low noise amplifier and related differential and single-ended amplification devices

摘要

A circuit includes a first pair of transistors connected in parallel between a first node and a second node with a diode-connected transistor coupled to the second node. A second pair of transistors has current terminals connected at a third node. A first and second current sink transistors are connected in a current mirror configuration with the diode-connected transistor and further coupled to the third node. A first differential amplifier has an output coupled to control terminals of the first and third transistors and an input coupled to a further current node of the third transistor. A second differential amplifier has an output coupled to control terminals of the second and fourth transistors and an input coupled to a further current node of the fourth transistor.

主权项

1. An apparatus, comprising a control circuit for generating a first control voltage, a second control voltage and a third control voltage, for controlling a low noise amplifier that includes a transconductance amplification stage controlled by said first control voltage, and a current steering stage controlled by said second control voltage and said third control voltage, said control circuit comprising:
a first pair of matched transistors, comprising first and second transistors having respective first current terminals connected in common and having respective second current terminals connected in common, and being respectively controlled by said third control voltage and said second control voltage; a diode-connected transistor coupled to said second current terminals of the first pair of matched transistors to sink currents flowing there through, said first control voltage being the voltage at the control terminal of the diode-connected transistor; a second pair of matched transistors comprising third and fourth transistors configured to be respectively controlled by said third control voltage and said second control voltage and to generate respective single-ended output voltages, having respective first current terminals connected in common, being of the same type of said first pair of matched transistors; a fifth transistor and a sixth transistor connected to mirror a current flowing through said diode-connected transistor and to sink currents flowing through said second pair of matched transistors; a first operational amplifier configured to generate said second control voltage as an amplified replica of a difference between said first output voltage and a first reference voltage; and a second operational amplifier configured to generate said third control voltage as an amplified replica of a difference between said second output voltage and a second reference voltage.