Apparatus and methods for envelope tracking systems with automatic mode selection

• US 10,454,428 B2
• Filed: 09/20/2018
• Issued: 10/22/2019
• Est. Priority Date: 09/14/2016
• Status: Active Grant

• Current Assignee: Skyworks Solutions Incorporated
• Original Assignee: Skyworks Solutions Incorporated
• Inventors: Khesback, Sabah, Drogi, Serge Francois, Balteanu, Florinel G.
• Primary Examiner(s): Patel, Dhaval V
• Application Number:
  US16/136,573
• Publication Number:
  US 20190020315A1
• Time in Patent Office: 397 Days
• CPC Class Codes: H03F 1/0227 using supply converters
• CPC Class Codes: H03F 1/025 by using a signal derived from the input signal
• CPC Class Codes: H03F 1/0261 with control of the polarisation voltage or current, e.g. gliding Class A
• CPC Class Codes: H03F 1/0277 Selecting one or more amplifiers from a plurality of amplifiers
• CPC Class Codes: H03F 1/3247 using feedback acting on predistortion circuits H03F1/3264 takes precedence
• CPC Class Codes: H03F 2200/102 A non-specified detector of a signal envelope being used in an amplifying circuit
• CPC Class Codes: H03F 2200/171 A filter circuit coupled to the output of an amplifier
• CPC Class Codes: H03F 2200/336 A I/Q, i.e. phase quadrature, modulator or demodulator being used in an amplifying circuit
• CPC Class Codes: H03F 2200/414 A switch being coupled in the output circuit of an amplifier to switch the output on/off
• CPC Class Codes: H03F 2200/417 A switch coupled in the output circuit of an amplifier being controlled by a circuit
• CPC Class Codes: H03F 2200/511 Many discrete supply voltages or currents or voltage levels can be chosen by a control signal in an IC-block amplifier circuit
• CPC Class Codes: H03F 2200/555 A voltage generating circuit being realised for biasing different circuit elements
• CPC Class Codes: H03F 3/195 in integrated circuits
• CPC Class Codes: H03F 3/245 with semiconductor devices only
• CPC Class Codes: H03F 3/45183 Long tailed pairs H03F3/4521, H03F3/45237 take precedence
• CPC Class Codes: H03G 1/0029 using FETs
• CPC Class Codes: H03G 1/0088 using discontinuously variable devices, e.g. switch-operated
• CPC Class Codes: H03G 3/001 Digital control of analog signals
• CPC Class Codes: H03G 3/3042 in modulators, frequency-changers, transmitters or power amplifiers transmission power control in bidirectional transmission systems H04W52/04

Abstract

Apparatus and methods for envelope tracking systems with automatic mode selection are provided herein. In certain configurations, a power amplifier system includes a power amplifier configured to provide amplification to a radio frequency signal and to receive power from a power amplifier supply voltage, and an envelope tracker including a signal bandwidth detection circuit configured to generate a detected bandwidth signal based on processing an envelope signal corresponding to an envelope of the radio frequency signal. The envelope tracker further includes a switch bank configured to receive a plurality of regulated voltages, a filter configured to filter an output of the switch bank to generate the power amplifier supply voltage, and a mode control circuit configured to control a filtering characteristic of the filter based on the detected bandwidth signal.

Claims

1. A power amplifier system comprising:

a power amplifier configured to provide amplification to a radio frequency signal and to receive power from a power amplifier supply voltage; and

an envelope tracker including a signal bandwidth detection circuit configured to generate a detected bandwidth signal based on processing an envelope signal corresponding to an envelope of the radio frequency signal, the envelope tracker further including a switch bank configured to receive a plurality of regulated voltages, a filter configured to filter an output of the switch bank to generate the power amplifier supply voltage, and a mode control circuit configured to control a filtering characteristic of the filter based on the detected bandwidth signal.

2. The power amplifier system of claim 1 wherein the switch bank includes a plurality of switches each configured to receive a respective one of the plurality of regulated voltages.

3. The power amplifier system of claim 2 wherein the envelope tracker further includes a coding and dithering circuit configured to control selection of the plurality of switches based on the envelope signal.

4. The power amplifier system of claim 3 wherein the envelope tracker further includes a plurality of comparators configured to provide the coding and dithering circuit with a plurality of comparison signals, each of the plurality of comparators configured to compare the envelope signal to a different comparison threshold.

5. The power amplifier system of claim 2 wherein the envelope tracker further includes a multi-output boost switcher configured to generate the plurality of regulated voltages based on DC-to-DC conversion of a battery voltage.

6. The power amplifier system of claim 1 wherein the signal bandwidth detection circuit includes a detector configured to generate a differential detection signal indicative of a root mean square of the envelope signal, and a plurality of converter cells arranged in a cascade and configured to process the differential detection signal to generate a plurality of currents, the detected bandwidth signal generated based on a sum of the plurality of currents.

7. The power amplifier system of claim 1 wherein the mode control circuit is further configured to process the detected bandwidth signal to determine a number of resource blocks used by the radio frequency signal.

8. The power amplifier system of claim 1 wherein the mode control circuit is configured to control a filter bandwidth of the filter based on the detected bandwidth signal.

9. The power amplifier system of claim 1 wherein the mode control circuit is configured to control a corner frequency of the filter based on the detected bandwidth signal.

10. A mobile device comprising:

a power amplifier configured to amplify a radio frequency signal to generate an amplified radio frequency signal, the power amplifier configured to receive power from a power amplifier supply voltage;

a transceiver configured to generate the radio frequency signal and an envelope signal corresponding to an envelope of the radio frequency signal; and

an envelope tracker including a signal bandwidth detection circuit configured to generate a detected bandwidth signal based on processing the envelope signal, a switch bank configured to receive a plurality of regulated voltages, a filter configured to filter an output of the switch bank to generate the power amplifier supply voltage, and a mode control circuit configured to control a filtering characteristic of the filter based on the detected bandwidth signal.

11. The mobile device of claim 10 further comprising an antenna configured to transmit the amplified radio frequency signal.

12. The mobile device of claim 10 wherein the switch bank includes a plurality of switches each configured to receive a respective one of the plurality of regulated voltages.

13. The mobile device of claim 12 wherein the envelope tracker further includes a coding and dithering circuit configured to control selection of the plurality of switches based on the envelope signal.

14. The mobile device of claim 13 wherein the envelope tracker further includes a plurality of comparators configured to provide the coding and dithering circuit with a plurality of comparison signals, each of the plurality of comparators configured to compare the envelope signal to a different comparison threshold.

15. The mobile device of claim 12 wherein the envelope tracker further includes a multi-output boost switcher configured to generate the plurality of regulated voltages based on DC-to-DC conversion of a battery voltage.

16. The mobile device of claim 10 wherein the mode control circuit is configured to control a filter bandwidth of the filter based on the detected bandwidth signal.

17. A packaged module comprising:

a package substrate; and

a semiconductor die attached to the package substrate and including an envelope tracker configured to generate a power amplifier supply voltage for a power amplifier that amplifies a radio frequency signal, the envelope tracker including a signal bandwidth detection circuit configured to generate a detected bandwidth signal based on processing an envelope signal corresponding to an envelope of the radio frequency signal, a switch bank configured to receive a plurality of regulated voltages, a filter configured to filter an output of the switch bank to generate the power amplifier supply voltage, and a mode control circuit configured to control a filtering characteristic of the filter based on the detected bandwidth signal.

18. The packaged module of claim 17 wherein the switch bank includes a plurality of switches each configured to receive a respective one of the plurality of regulated voltages.

19. The packaged module of claim 18 wherein the envelope tracker further includes a coding and dithering circuit configured to control selection of the plurality of switches based on the envelope signal.

20. The packaged module of claim 19 wherein the envelope tracker further includes a plurality of comparators configured to provide the coding and dithering circuit with a plurality of comparison signals, each of the plurality of comparators configured to compare the envelope signal to a different comparison threshold.