Envelope tracking amplifier

摘要

An envelope tracking power amplifier uses signal cancellation techniques to provide isolation between RF signals and envelope signals, without the use of filters. In this manner, the envelope tracking power amplifier is capable of operating with envelope signals that are at or near the frequency of the corresponding RF signals. In at least one embodiment, a double balanced power amplifier is provided that includes a balanced RF input port (20), a balanced RF output port (22), and a balanced envelope input port (32). The balanced nature of the amplifier results in ports of the amplifier forming virtual grounds with respect to signals at other ports. In some other embodiments, a single balanced amplifier is provided that provides isolation between ports thereof.