# US 12,224,711 B2 · Target voltage generation in an envelope tracking integrated circuit

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- Number: US 12,224,711 B2
- Document ID: US12224711B2
- Status: Granted
- Kind: B2
- Application number: 17/523,966
- Filed: 2021-11-11
- Published: 2022-11-10
- Granted: 2025-02-11
- Earliest claimed: 2021-05-07
- Assignees: Qorvo US, Inc.
- Applicants: Qorvo US, Inc.
- Inventors: Nadim Khlat
- Web page: https://patentgrep.com/patent/US12224711B2

## CPC

- H03F 1/0216: {Continuous control}
- H03F 1/0227: {using supply converters}
- H03F 3/19: with semiconductor devices only
- H03F 3/245: {with semiconductor devices only}
- H03F 2200/102: A non-specified detector of a signal envelope being used in an amplifying circuit
- H03F 2200/105: A non-specified detector of the power of a signal being used in an amplifying circuit
- H03F 2200/375: Circuitry to compensate the offset being present in an amplifier
- H03F 2200/451: the amplifier being a radio frequency amplifier
- Y02D 30/70: in wireless communication networks
- H03F: AMPLIFIERS
- Y02D: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE

## Abstract

Target voltage generation in an envelope tracking (ET) integrated circuit (ETIC) is provided. The ETIC is configured to generate a time-variant ET voltage based on a time-variant target voltage for amplifying a radio frequency (RF) signal modulated for communication in multiple time intervals. In embodiments disclosed herein, the ETIC is self-contained to generate the time-variant target voltage based on a sensed signal having a time-variant sensed envelope that tracks a time-variant power envelope of the RF signal. Since the time-variant target voltage is generated to track the time-variant sensed envelope, which further tracks the time-variant power envelope, the time-variant ET voltage can better track the time-variant power envelope of the RF signal when the time-variant ET voltage is provided to a power amplifier(s) that amplifies the RF signal.

## Claims

### Claim 1

An envelope tracking (ET) integrated circuit (ETIC) comprising:
an ET voltage circuit configured to:
generate a time-variant ET voltage based on a time-variant target voltage for amplifying a radio frequency (RF) signal in a plurality of time intervals; and
generate a sensed signal having a time-variant sensed envelope that tracks a high-frequency current flowing inside the ET voltage circuit and varying in accordance with a time-variant power envelope of the RF signal; and
a target voltage generation circuit configured to generate the time-variant target voltage based on the time-variant sensed envelope to thereby cause the time-variant ET voltage to track the time-variant power envelope of the RF signal.

### Claim 2 (depends on 1)

The ETIC of claim 1, wherein the ET voltage circuit is further configured to generate the sensed signal comprising a sensed current having a time-variant current envelope that tracks the time-variant power envelope of the RF signal.

### Claim 3 (depends on 1)

The ETIC of claim 1, wherein the ET voltage circuit is further configured to generate the sensed signal comprising a sensed voltage having a time-variant voltage envelope that tracks the time-variant power envelope of the RF signal.

### Claim 4 (depends on 1)

The ETIC of claim 1, wherein the target voltage generation circuit comprises:
a detection circuit configured to detect one or more peaks of the time-variant sensed envelope in a respective one of the plurality of time intervals; and
a voltage selection circuit configured to cause the time-variant target voltage to increase in response to the detection circuit detecting the one or more peaks in the respective one of the plurality of time intervals.

### Claim 5 (depends on 4)

The ETIC of claim 4, wherein the detection circuit is further configured to detect the one or more peaks of the time-variant sensed envelope in response to the time-variant sensed envelope being higher than a peak detection threshold.

### Claim 6 (depends on 5)

The ETIC of claim 5, wherein the peak detection threshold is a function of an average of the time-variant ET voltage.

### Claim 7 (depends on 4)

The ETIC of claim 4, wherein the voltage selection circuit is further configured to cause the time-variant target voltage to increase as a function of an expected peak-to-average ratio (PAR) in the respective one of the plurality of time intervals.

### Claim 8 (depends on 4)

The ETIC of claim 4, wherein the detection circuit is further configured to provide a digital indication signal to the voltage selection circuit in response to detecting the one or more peaks of the time-variant sensed envelope, the digital indication signal comprising a coded digital word that indicates the one or more detected peaks of the time-variant sensed envelope.

### Claim 9 (depends on 8)

The ETIC of claim 8, wherein the voltage selection circuit is further configured to generate a time-variant digital target voltage based on the coded digital word received in the digital indication signal.

### Claim 10 (depends on 9)

The ETIC of claim 9, wherein the voltage selection circuit is further configured to increase the time-variant digital target voltage in response to receiving the coded digital word that indicates the one or more detected peaks of the time-variant sensed envelope to thereby cause the time-variant target voltage to increase.

### Claim 11 (depends on 9)

The ETIC of claim 9, wherein the target voltage generation circuit further comprises a digital-to-analog converter (DAC) configured to convert the time-variant digital target voltage to the time-variant target voltage.

### Claim 12 (depends on 4)

The ETIC of claim 4, wherein the voltage selection circuit is further configured to cause the time-variant target voltage to decay at a start of each of the plurality of time intervals from a level of the time-variant target voltage at an end of an immediately preceding one of the plurality of time intervals.

### Claim 13 (depends on 12)

The ETIC of claim 12, wherein the voltage selection circuit is further configured to cause the time-variant target voltage to decay until the one or more peaks of the time-variant sensed envelope are detected.

### Claim 14 (depends on 12)

The ETIC of claim 12, wherein the voltage selection circuit is further configured to cause the time-variant target voltage to decay to a predefined minimum target voltage.

### Claim 15 (depends on 1)

The ETIC of claim 1, wherein the ET voltage circuit comprises:
a voltage amplifier configured to generate an initial ET voltage based on the time-variant target voltage; and
an offset capacitor configured to raise the initial ET voltage by an offset voltage to thereby generate the time-variant ET voltage.

### Claim 16 (depends on 15)

The ETIC of claim 15, wherein the voltage amplifier is further configured to:
source the high-frequency current in response to each peak of the time-variant power envelope; and
sink the high-frequency current in response to each bottom of the time-variant power envelope.

### Claim 17 (depends on 16)

The ETIC of claim 16, wherein the voltage amplifier is further configured to generate the sensed signal to indicate an amount of the high-frequency current that is sourced or sunk by the voltage amplifier.

### Claim 18 (depends on 15)

The ETIC of claim 15, further comprising a switcher circuit configured to modulate the offset voltage.

### Claim 19 (depends on 18)

The ETIC of claim 18, wherein the switcher circuit comprises:
a multi-level charge pump (MCP) configured to generate a low-frequency voltage as a function of a battery voltage in accordance with a duty cycle; and
a power inductor configured to induce a low-frequency current to thereby modulate the offset capacitor to the offset voltage.

### Claim 20 (depends on 1)

The ETIC of claim 1, wherein each of the plurality of time intervals has a duration of an orthogonal frequency division multiplexing (OFDM) symbol.