Patent ID: 6437647
Filing Date: 2002-08-20
Classification: H03F

Abstract:
A system that stabilizes quiescent current in radio frequency (RF) transistors, comprising:a mirror transistor having a base and a current rating; an RF transistor having a base, a quiescent current and a collector, the collector coupled to a power source; a buffer transistor having a base, an emitter, and a current rating, the emitter of the buffer transistor coupled to the base of the RF transistor; a first compensating impedance element having a resistance, the first compensating impedance element coupled to the base of the mirror transistor; and a second compensating impedance element having a resistance, the second compensating impedance element coupled to the base of the buffer transistor, such that the resistance of the first compensating impedance element is equal to the resistance of the second compensating impedance element multiplied by a factor, the factor equal to a ratio of the current rating of the buffer transistor to the current rating of the mirror transistor, and such that the quiescent current remains substantially constant after a variation in the power source.