Patent attributes
An architecture, circuits, systems and a method for amplifying an analog signal. The architecture and/or circuit generally includes a first fixed stage (e.g., a predriver) and an adjustable stage. The first fixed stage may be configured to amplify an analog signal and provide a first amplified analog output at a first common node. The adjustable stage may comprise a plurality of independently selectable parallel amplifier segments. Each of the parallel segments may have an input at the first common node and an output at a second common node, a transistor having a control terminal, and a first inductor in electrical communication with the control terminal of the transistor. The adjustable stage may be configured to apply a bias to the control terminal of the transistor in a selected segment and to provide an output signal in one of a plurality of a power ranges corresponding to a number of selected parallel amplifier segments. The output signal generally has a minimum power efficiency when two or more of the parallel segments are selected. The present invention advantageously provides a relatively compact power amplifier with an extended output power range at which the amplifier is highly efficient. In preferred embodiments, the input and output matching characteristics are generally independent of the number of selected output amplifier segments.
