Envelope tracking system with modeling of a power amplifier supply voltage filter

Patent metadata

Field	Value
Publication number	US-11038471-B2
Application number	US-201916678696-A
Country	US
Kind code	B2
Filing date	Nov 8, 2019
Priority date	Nov 20, 2018
Publication date	Jun 15, 2021
Grant date	Jun 15, 2021

Abstract

Envelope tracking systems with modeling for power amplifier supply voltage filtering are provided herein. In certain embodiments, an envelope tracking system includes a supply voltage filter, a power amplifier that receives a power amplifier supply voltage through the supply voltage filter, and an envelope tracker that generates the power amplifier supply voltage. The power amplifier provides amplification to a radio frequency (RF) signal that is generated based on digital signal data, and the envelope tracker generates the power amplifier supply voltage based on an envelope signal corresponding to an envelope of the RF signal. The envelope tracking system further includes digital modeling circuitry that models the supply voltage filter and operates to digitally compensate the digital signal data for effects of the supply voltage filter, such as distortion.

First claim

What is claimed is:

1. An envelope tracking system comprising:
a modulator configured to generate a radio frequency signal based on digital signal data;
a supply voltage filter;
a power amplifier configured to amplify the radio frequency signal and to receive power from a power amplifier supply voltage through the supply voltage filter;
an envelope tracker configured to generate the power amplifier supply voltage based on an envelope signal corresponding to an envelope of the radio frequency signal; and
digital modeling circuitry operable to model the supply voltage filter and to compensate the digital signal data for distortion arising from the supply voltage filter.

2. The envelope tracking system of claim 1 further comprising an analog-to-digital converter configured to generate a digital representation of the power amplifier supply voltage, the digital modeling circuitry calibrated based on the digital representation of the power amplifier supply voltage.

3. The envelope tracking system of claim 1 further comprising an amplitude extraction circuit configured to process the digital signal data to generate digital envelope data and a shaping circuit configured to process the digital envelope data to generate shaped envelope data, the envelope signal generated based on the shaped envelope data.

4. The envelope tracking system of claim 3 wherein the digital modeling circuitry is further configured to compensate the digital signal data based on the shaped envelope data.

5. The envelope tracking system of claim 3 further comprising digital pre-distortion circuitry configured to digitally pre-distort the digital signal data, the amplitude extraction circuit configured to generate the digital envelope data based on the digital signal data after digital pre-distortion.

6. The envelope tracking system of claim 3 wherein the shaping table includes an envelope tracking lookup table mapping a plurality of envelope levels of the digital envelope data to a plurality of corresponding shaped envelope levels of the shaped envelope data.

7. The envelope tracking system of claim 1 wherein the supply voltage filter includes at least one series inductor.

8. The envelope tracking system of claim 1 wherein the supply voltage filter includes at least one shunt capacitor.

9. The envelope tracking system of claim 1 further comprising digital pre-distortion circuitry configured to digitally pre-distort the digital signal data, the digital pre-distortion circuitry configured to receive a digital compensation signal from the digital modeling circuitry.

10. The envelope tracking system of claim 1 wherein the envelope tracker is a multi-level envelope tracker including a DC-to-DC converter configured to output a plurality of regulated voltages and a modulator having an output configured to control the power amplifier supply voltage based on the plurality of regulated voltages and the envelope signal.

11. A mobile device comprising:
a transceiver configured to generate a radio frequency signal based on digital signal data;
a front end circuit including a supply voltage filter and a power amplifier configured to amplify the radio frequency signal and to receive power from a power amplifier supply voltage through the supply voltage filter;
a power management circuit including an envelope tracker configured to generate the power amplifier supply voltage based on an envelope signal corresponding to an envelope of the radio frequency signal; and
a baseband circuit including digital modeling circuitry operable to model the supply voltage filter and to compensate the digital signal data for distortion arising from the supply voltage filter.

12. The mobile device of claim 11 wherein the baseband circuit further includes an analog-to-digital converter configured to generate a digital representation of the power amplifier supply voltage, the digital modeling circuitry calibrated based on the digital representation.

13. The mobile device of claim 11 wherein the baseband circuit further includes an amplitude extraction circuit configured to process the digital signal data to generate digital envelope data and a shaping circuit configured to process the digital envelope data to generate shaped envelope data, the envelope signal generated based on the shaped envelope data.

14. The mobile device of claim 13 wherein the digital modeling circuitry is further configured to compensate the digital signal data based on the shaped envelope data.

15. The mobile device of claim 13 wherein the baseband circuit further includes digital pre-distortion circuitry configured to digitally pre-distort the digital signal data, the amplitude extraction circuit configured to generate the digital envelope data based on the digital signal data after digital pre-distortion.

16. A method of envelope tracking, the method comprising:
generating a radio frequency signal based on digital signal data;
amplifying the radio frequency signal using a power amplifier;
providing a power amplifier supply voltage to the power amplifier through a supply voltage filter;
generating the power amplifier supply voltage based on an envelope signal corresponding to an envelope of the radio frequency signal using an envelope tracker; and
compensating the digital signal data for distortion arising from the supply voltage filter using a digital model of the supply voltage filter.

17. The method of claim 16 further comprising generating a digital representation of the power amplifier supply voltage using an analog-to-digital converter, and calibrating the digital model based on the digital representation.

18. The method of claim 16 further comprising processing the digital signal data to generate digital envelope data, shaping the digital envelope data to generate shaped envelope data, and generating the envelope signal based on the shaped envelope data.

19. The method of claim 18 further comprising compensating the digital signal data using the digital model based on the shaped envelope data.

20. The method of claim 18 further comprising digitally pre-distorting the digital signal data before processing the digital signal data to generate digital envelope data.

Assignees

• Skyworks Solutions Inc

Inventors

• Drogi Serge Francois
• Balteanu Florinel G
• Farahvash Shayan

Classifications

• H03F2200/102

  A non-specified detector of a signal envelope being used in an amplifying circuit · CPC title

• H03F2200/504

  the supply voltage or current being continuously controlled by a controlling signal, e.g. the controlling signal of a transistor implemented as variable resistor in a supply path for, an IC-block showed amplifier · CPC title

• G06F30/367 Primary

  Design verification, e.g. using simulation, simulation program with integrated circuit emphasis [SPICE], direct methods or relaxation methods · CPC title

• G06F2119/10

  Noise analysis or noise optimisation · CPC title

• G06F2119/06

  Power analysis or power optimisation · CPC title