Patent ID: 7598810
Filing Date: 2009-10-06
Classification: H03F

Abstract:
1. A power amplifier, comprising: a first transformer comprising a first primary coil for receiving an input signal, and a first secondary coil; a first transistor comprising a first base, a first collector and a first emitter, the first emitter being coupled to a first end of the first secondary coil, and the first emitter being grounded and coupled to a second end of the first secondary coil; a first resistor coupled between the first base and the first collector; a second transformer comprising a second primary coil and a second secondary coil, a first end of the second primary coil being coupled to a second end of the first primary coil, and a second end of the second primary coil being grounded; a second transistor comprising a second base, a second collector for generating an output signal, and a second emitter, the second base being coupled to a first end of the second secondary coil, and the second emitter being coupled to the first collector and a second end of the second secondary coil; a second resistor coupled between the second base and the second collector; and a bias circuit having a first end coupled to the second collector, and a second end for receiving a supply voltage.