| CPC H03F 3/245 (2013.01) [H03F 3/195 (2013.01); H03G 3/3047 (2013.01); H03F 2200/447 (2013.01); H03F 2200/451 (2013.01); H03G 2201/708 (2013.01)] | 7 Claims |
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1. A radio frequency (RF) power amplifier architecture and circuits comprising an integrated circuit for adjusting power amplifier output gain during a signal burst interval, comprising:
an amplifier transistor controlling and providing gain to an output current flowing between a voltage supply coupled to the transistor's output terminal and ground;
a first circuit comprising a current mirror circuit providing a bias voltage at a first terminal which is coupled through a resistor to an input terminal of the amplifier transistor; and
a second circuit connected to the current mirror circuit at the first terminal providing a signal to modify the bias voltage following a turn-on portion of the signal burst interval, wherein the second circuit comprises a resistor-capacitor network, and wherein the capacitor in the resistor-capacitor network is a capacitor that is connected to external pins of the package of the integrated circuit; and
wherein the second circuit causes amplifier transistor output gain to slowly rise to a design target value over a time interval characterized by a time constant, wherein the electrical time constant of the resistor-capacitor network matches a thermal time constant of the amplifier transistor; and
wherein the combined first and second circuits reduce amplifier transistor output gain following the turn-on portion of the signal burst interval by increasing the bias voltage on the amplifier transistor to compensate for a decrease in amplifier transistor gain due to thermal self-heating in the amplifier transistor following the turn-on portion of the signal burst interval and thereby provide uniform gain throughout the signal burst interval.
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