The MLS envelope tracker 9 controls the first power amplifier supply voltage V_PA1 to track an envelope of a first RF signal amplified by the first power amplifier 21. Additionally, the MLS envelope tracker 9 controls the second power amplifier supply voltage V_PA2 to track an envelope of a second RF signal amplified by the second power amplifier 22. In certain implementations, the MLS envelope tracker 9 receives one or more envelope signals from the baseband modem 11. For example, the MLS envelope tracker 9 can receive a first envelope signal indicating an envelope of the first RF signal and a second envelope signal indicating an envelope of the second RF signal.

The battery 8 can be any suitable battery for use in the mobile device 70, including, for example, a lithium-ion battery. The battery voltage V_BATT is regulated by a DC-to-DC converter of the MLS envelope tracker 9 to generate regulated voltages used for multi-level envelope tracking in accordance with the teachings herein.

The transceiver 10 generates RF signals for transmission and processes incoming RF signals received from the primary antenna 1 and the diversity antenna 2. It will be understood that various functionalities associated with the transmission and receiving of RF signals can be achieved by one or more components that are collectively represented in FIG. 1 as the transceiver 10. In one example, separate components (for instance, separate circuits or dies) can be provided for handling certain types of RF signals.