Apple Inc.
High Efficiency Switching Power Amplifier

Abstract:

A power amplifier and method for operating the same is disclosed. The amplifier includes a number of transistors coupled in series between a power node and a ground node. These transistors include a first transistor having a source terminal coupled to the power node, and a second transistor having its source terminal coupled to a ground node. A subset of transistors is also coupled in series between the first and second transistors. During operation in a first mode, the first and second transistors act as switching transistors, switching according to data received thereby. The subset of transistors, during the first mode, act as cascode transistors. During a second mode of operation, the transistors of the subset act as switching transistors, switching in accordance with the received data.