US 6,052,032 A · Radio frequency amplifiers

Abstract

A radio frequency amplifier having a power transistor (Q1) to the base of which is coupled a radio frequency signal to be amplified. An amplified radio frequency signal is provided at the collector of the power transistor (Q1). A control transistor (Qc) has its base coupled to the base of the power transistor (Q1) while a driver transistor (Q2) provides a control bias signal to the bases of the control and power transistors. A differential amplifier (Qd1, Qd2) has a first input coupled to an input bias signal and an output coupled to the base of the driver transistor (Q2). The collector of the control transistor (Qc) is coupled to a second input of the differential amplifier to provide a negative feedback signal to the differential amplifier and the driver transistor (Q2) and thereby to stabilise the operating point of the power transistor (Q1).

Claims9

Dependent claims

A radio frequency amplifier comprising:

a power transistor having an input for receiving a radio frequency signal to be amplified and an output for providing an amplified radio frequency signal;
a control transistor having an input coupled to said input of the power transistor;
a driver transistor having an output coupled to said inputs of the power and control transistors for providing a control bias signal to the power and control transistors;
and
a differential amplifier having a first input coupled to an input signal and an output coupled to an input of the driver transistor for providing a driver control signal to the driver transistor,
the control transistor having an output coupled to a second input of the differential amplifier, wherein the output of the control transistor tends to follow the output of the power transistor and provides a negative feedback signal to the differential amplifier.

3 more elements

Dependencies are inferred from the claim text.

Radio frequency amplifiers

Life of this patent

Radio frequency amplifiers

Life of this patent

Abstract

Claims9