Patent ID: 6538515
Filing Date: 2003-03-25
Classification: H03F

Abstract:
A power amplifier, comprising:a first circuit including a first transistor having an input terminal for receiving a radio frequency (RF) input, a first output terminal connected to ground, and a second output terminal connected to a first inductor connected in series with a capacitor and also connected to a voltage supply through a first controllable connector; a second circuit including a second transistor having an input terminal for receiving the radio frequency (RF) input, a first output terminal connected to ground, and a second output terminal connected to a second inductor connected in series with the capacitor and also connected to a voltage supply through a second controllable connector; bias means for biasing the first transistor and the second transistor, wherein the first circuit is connected in parallel to the second circuit; wherein the power amplifier is adapted to be operated in at least two output-power modes; wherein, in a first output-power mode of the at least two output-power modes, the first transistor and the second transistor are connected to the voltage supply and a bias voltage for the first transistor is at a normal level; and wherein, in a second output-power-mode of the at least two output-power modes, the first transistor is disconnected from the voltage supply and the bias voltage for the first transistor is at a level greater than the normal level, the first transistor thereby providing a low resistance to ground.