Patent ID: 6529065
Filing Date: 2003-03-04
Classification: H03F

Abstract:
A circuit configuration for active control of an operating point of a first bipolar transistor in a power amplifier circuit, comprising:a current mirror circuit having the first bipolar transistor and a second bipolar transistor, the first bipolar transistor having a control input, a collector and an emitter, said second bipolar transistor having a control input, a collector and an emitter, the control input of the first bipolar transistor and said control input of said second bipolar transistor being connected to one another for causing a collector current in one of the first bipolar transistor and said second bipolar transistor to produce a mirror collector current in the other of the first bipolar transistor and said second bipolar transistor; a third transistor provided in a common emitter amplifier circuit and having a control input, a collector and an emitter, said control input of said third transistor connected to said collector of said second bipolar transistor; a fourth transistor provided in the common emitter amplifier circuit and having a control input, a collector and an emitter, said control input of said fourth transistor connected to said collector of said third transistor; a fifth transistor provided in a common collector circuit and having a control input, a collector and an emitter, said control input of said fifth transistor connected to said collector of said fourth transistor and said emitter of said fifth transistor connected to said control input of said second bipolar transistor; a resistor connected to said collector of said second bipolar transistor; and a voltage source connected to said resistor and through said resistor to said collector of said second bipolar transistor.