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 amplifiers are 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, a balanced RF output port, and a balanced envelope input port. 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.

主权项

1. An envelope tracking power amplifier, comprising:
an amplifier core having at least two field effect transistors (FETs) coupled in a balanced configuration; an RF input port coupled to the amplifier core to provide an RF input signal to the amplifier core; an RF output port coupled to the amplifier core to output an amplified RF output signal; and an envelope input port coupled to the amplifier core to provide an envelope signal to the amplifier core, the envelope signal being representative of an envelope of the RF input signal; wherein the envelope input port forms a virtual ground with respect to signals at the RF input and output ports, and the RF output port forms a virtual ground with respect to a signal at the envelope input port.