公开(公告)号：US10862428B2

公开(公告)日：2020-12-08

申请号：US16140991

申请日：2018-09-25

Applicant: Apple Inc.

Inventor： Stephan Henzler ,  Andreas Menkhoff ,  Thomas Eichler ,  Wolfgang Walthes ,  Alexander Belitzer ,  Yifan Wang

IPC: H03F1/30 ,  H03F1/02 ,  H03F3/19 ,  H03F3/21 ,  H02M3/07 ,  H03M1/66 ,  H03F3/189 ,  H03F3/24 ,  H03F3/68 ,  H02M3/158

Abstract: An envelope tracking system for controlling a power amplifier supply voltage includes envelope circuitry and a feed forward digital to analog converter (DAC) circuitry. The envelope circuitry is configured to generate a target envelope signal based on a selected power amplifier supply voltage. The feed forward DAC circuitry includes a voltage source circuitry and a selector circuitry. The voltage source circuitry is configured to generate a plurality of voltages. The selector circuitry is configured to select one of the plurality of voltages based at least on the target envelope signal. The feed forward DAC circuitry is configured to provide the selected voltage to a supply voltage input of a power amplifier that amplifies a radio frequency (RF) transmit signal.

公开(公告)号：US11271600B2

公开(公告)日：2022-03-08

申请号：US16976657

申请日：2018-03-27

Applicant: Apple Inc.

Inventor： Alexander Belitzer ,  Yaron Yoffe ,  Yaniv Cohen ,  Michael Kerner

IPC: H04W76/23 ,  H04W24/08 ,  H04W76/10 ,  A61N1/39 ,  H04B1/04 ,  H03F1/02 ,  H03F1/32 ,  H03F3/24

Abstract: A transmitter is provided. The transmitter includes an envelope tracking circuit, wherein the envelope tracking circuit includes an envelope circuit configured to generate, based on a baseband signal, an envelope signal indicating a temporal course of the baseband signal's envelope. Further, the envelope tracking circuit includes a bandwidth reduction circuit configured to generate a bandwidth reduced envelope signal based on the envelope signal, and a DC-to-DC converter configured to generate a supply voltage for a power amplifier of the transmitter based on the bandwidth reduced envelope signal. The transmitter additionally includes a predistortion circuit configured to generate a predistorted baseband signal based on the baseband signal and an adjustable predistortion configuration. The predistortion circuit is further configured to adjust the predistortion configuration based on the bandwidth reduced envelope signal.