| 摘要 |
An amplifier arrangement 100 for optimising efficiency at a peak power level and a back-off power level comprises a main power amplifier 105 provided in a main branch for receiving a first signal 103, the main power amplifier being configured to operate in a class-B mode of operation. An auxiliary power amplifier 106 is provided in an auxiliary branch for receiving a second signal 104, the auxiliary power amplifier being configured to operate in a class-C mode of operation. The main power amplifier 105 and the auxiliary power amplifier 106 are substantially matched in size. The first signal 103 and the second signal 104 have a phase offset value θ that is selected in relation to a particular back-off power level γ of operation, wherein 0 < θ < 180°. A combining network 107 is configured to couple the output signals 108, 109 of the main and auxiliary amplifiers 105, 106 to an output node 110 of the amplifier arrangement such that the output of the auxiliary power amplifier load modulates the output of the main power amplifier. The circuit element values of the combining network 107 are derived based on the selected phase shift value θand the related back-off power level γ at which the amplifier arrangement is optimised for efficiency. |
