Patent ID: 6774724
Filing Date: 2004-08-10
Classification: H03F

Abstract:
An active self-bias compensation circuit for use with a radio frequency (â€œRFâ€ ) power amplifier, said RF power amplifier having an input, an output, a first transistor, and a plurality of operating performance characteristics responsive to a quiescent operating point established by a bias current in the RF power amplifier, said active bias compensation circuit comprising:a second transistor having a first, second and third terminal and configured to have essentially the same electrical and thermal characteristics as said first transistor, wherein the second terminal of said second transistor is operatively coupled to said RF power amplifier and the third terminal is coupled to a first fixed voltage; and a first circuit coupled between the first and second terminal of said second transistor for causing a reference current in said second transistor to be set and maintained at a first predetermined fixed value and for causing said bias current to be set and maintained at a second predetermined fixed value that is a factor of said first predetermined fixed value, said first circuit comprising a first, second and third resistor and a voltage source, said first resistor coupled between the first terminal of said second transistor and said voltage source, said second resistor coupled between the first and second terminals of said second transistor, and said third resistor coupled between a ground potential and the junction of said second resistor and the second terminal of said second transistor.