Feed-forward envelope tracking

Patent metadata

Field	Value
Publication number	US-10862428-B2
Application number	US-201816140991-A
Country	US
Kind code	B2
Filing date	Sep 25, 2018
Priority date	Mar 30, 2017
Publication date	Dec 8, 2020
Grant date	Dec 8, 2020

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.

First claim

The invention claimed is:

1. An envelope tracking system for controlling a power amplifier supply voltage or bias, comprising:
a voltage source circuitry configured to generate a plurality of voltages;
a selector circuitry configured to select one of the plurality of voltages based on a target envelope signal that is associated with an envelope of a radio frequency (RF) transmit signal,
wherein the selector circuitry is configured to output the selected voltage for coupling to a supply voltage input or a bias input of a power amplifier that amplifies the RF transmit signal,
wherein the target envelope signal includes voltage information that identifies which of the plurality of voltages to select, and
wherein the target envelope signal includes time information comprising a start time to output the selected voltage from the selector circuitry.

2. The envelope tracking system of claim 1 , wherein the time information comprises a predetermined time period within which the selected voltage is output from the selector circuitry.

3. The envelope tracking system of claim 1 , wherein the time information further comprises a duration from the start time in which the selected voltage is output from the selector circuitry.

4. The envelope tracking system of claim 1 , wherein the time information further comprises an end time to discontinue the output of the selected voltage from the selector circuitry.

5. A method configured to provide a supply voltage to a power amplifier, the method comprising:
generating a plurality of voltages;
receiving a target envelope signal based on an envelope of a radio frequency (RF) transmit signal;
selecting one of the plurality of voltages based at least on the target envelope signal that communicates voltage information and time information; and
providing the selected voltage to an output terminal that is configured to couple to a supply voltage input of a power amplifier that amplifies the RF transmit signal,
wherein the voltage information identifies which of the plurality of voltages to select, and
wherein the time information comprises a start time to output the selected voltage from a selector circuitry.

6. The method of claim 5 , wherein the time information comprises a predetermined time period within which the selected voltage is output from the selector circuitry.

7. The method of claim 5 , wherein the time information further comprises a duration from the start time in which the selected voltage is output from the selector circuitry.

8. The method of claim 5 , wherein the time information further comprises an end time to discontinue the output of the selected voltage from the selector circuitry.

9. A feed forward envelope tracking circuitry, comprising:
a voltage source circuitry configured to generate a plurality of voltages; and
a selector circuitry configured to select one of the plurality of voltages based at least on a target envelope signal that is associated with an envelope of a radio frequency (RF) transmit signal, wherein the target envelope signal includes voltage information that identifies which of the plurality of voltages to select and time information comprising a start time to provide the selected voltage to an output thereof;
wherein the selector circuitry output is configured to couple to a supply voltage input of a power amplifier that amplifies the RF transmit signal.

10. The feed forward envelope tracking circuitry of claim 9 , wherein the time information comprises a predetermined time period within which to provide the selected voltage.

11. The feed forward envelope tracking circuitry of claim 9 , wherein the time information further comprises a duration from the start time in which to provide the selected voltage.

12. The feed forward envelope tracking circuitry of claim 9 , wherein the time information further comprises an end time to discontinue the providing of the selected voltage.

Assignees

• Apple Inc

Inventors

• Henzler Stephan
• Menkhoff Andreas
• Eichler Thomas
• Walthes Wolfgang
• Belitzer Alexander
• Wang Yifan

Classifications

• H03F1/0227 Primary

  using supply converters · CPC title

• H03F2200/451

  the amplifier being a radio frequency amplifier · CPC title

• H02M3/07

  using capacitors charged and discharged alternately by semiconductor devices with control electrode {, e.g. charge pumps} · CPC title

• H02M3/158

  including plural semiconductor devices as final control devices for a single load · CPC title

• H03F3/189

  High-frequency amplifiers, e.g. radio frequency amplifiers · CPC title