US-12627269-B2 - Envelope tracking integrated circuit operable across wide modulation bandwidth

Abstract

An envelope tracking (ET) integrated circuit (ETIC) operable across wide modulation bandwidth is disclosed. The ETIC includes at least two auxiliary voltage outputs coupled to a high-bandwidth power amplifier circuit that has a lower equivalent capacitance, and thus a higher impedance resonance frequency. The ETIC also includes a pair of ET voltage circuits configured to generate a pair of ET voltages, respectively. To help mitigate potential distortion in the ET voltages, a control circuit is configured to couple the ET voltage circuits exclusively to the auxiliary voltage outputs when the ETIC needs to operate with a high modulation bandwidth (e.g., ≥200 MHz). Given the higher impedance resonance frequency of the high-bandwidth power amplifier circuit, it is possible to increase separation between an energy spectrum of a voltage disturbance and an energy spectrum of the high modulation bandwidth, thus helping to reduce the potential distortion in the ET voltages.

Inventors

• Nadim Khlat

Assignees

• QORVO US, INC.

Dates

Publication Date

20260512

Application Date

20210917

Claims (18)

1. 1 . An envelope tracking (ET) integrated circuit (ETIC) comprising: at least two primary voltage outputs each coupled to a respective one of at least two low-bandwidth power amplifier circuits each having a first equivalent capacitance; at least two auxiliary voltage outputs coupled to a high-bandwidth power amplifier circuit having a second equivalent capacitance lower than the first equivalent capacitance to thereby cause the high-bandwidth power amplifier circuit to have a higher impedance resonance frequency than each of the at least two low-bandwidth power amplifier circuits; a first ET voltage circuit configured to generate a first ET voltage based on a first target voltage; a second ET voltage circuit configured to generate a second ET voltage based on a second target voltage; and a control circuit configured to: determine whether the ETIC needs to operate with a high modulation bandwidth or a low modulation bandwidth; and couple each of the first ET voltage circuit and the second ET voltage circuit to a respective one of the at least two primary voltage outputs in response to determining that the ETIC needs to operate with the low modulation bandwidth.
2. 2 . The ETIC of claim 1 , wherein the control circuit is further configured to decouple the first ET voltage circuit and the second ET voltage circuit from the at least two primary voltage outputs in response to determining that the ETIC needs to operate with the high modulation bandwidth.
3. 3 . The ETIC of claim 1 , wherein the control circuit is further configured to decouple the first ET voltage circuit and the second ET voltage circuit from the at least two auxiliary voltage outputs in response to determining that the ETIC needs to operate with the low modulation bandwidth.
4. 4 . The ETIC of claim 1 , wherein the control circuit is further configured to determine whether the ETIC needs to operate with the high modulation bandwidth or the low modulation bandwidth based on any one of the first target voltage and the second target voltage.
5. 5 . The ETIC of claim 4 , wherein the control circuit is further configured to determine whether the ETIC needs to operate with the high modulation bandwidth or the low modulation bandwidth based on a higher one of the first target voltage and the second target voltage.
6. 6 . The ETIC of claim 1 , further comprising: a first voltage equalizer circuit coupled to the first ET voltage circuit and configured to equalize the first target voltage based on a first transfer function; and a second voltage equalizer circuit coupled to the second ET voltage circuit and configured to equalize the second target voltage based on a second transfer function.
7. 7 . An envelope tracking (ET) power management circuit comprising: at least two low-bandwidth power amplifier circuits each having a first equivalent capacitance; a high-bandwidth power amplifier circuit having a second equivalent capacitance lower than the first equivalent capacitance to thereby cause the high-bandwidth power amplifier circuit to have a higher impedance resonance frequency than each of the at least two low-bandwidth power amplifier circuits; and an ET integrated circuit (ETIC) comprising: at least two primary voltage outputs each coupled to a respective one of the at least two low-bandwidth power amplifier circuits; at least two auxiliary voltage outputs coupled to the high-bandwidth power amplifier circuit; a first ET voltage circuit configured to generate a first ET voltage based on a first target voltage; a second ET voltage circuit configured to generate a second ET voltage based on a second target voltage; and a control circuit configured to: determine whether the ETIC needs to operate with a high modulation bandwidth or a low modulation bandwidth; couple each of the first ET voltage circuit and the second ET voltage circuit to a respective one of the at least two auxiliary voltage outputs in response to determining that the ETIC needs to operate with the high modulation bandwidth; and couple each of the first ET voltage circuit and the second ET voltage circuit to a respective one of the at least two primary voltage outputs in response to determining that the ETIC needs to operate with the low modulation bandwidth.
8. 8 . The ET power management circuit of claim 7 , wherein the control circuit is further configured to decouple the first ET voltage circuit and the second ET voltage circuit from the at least two primary voltage outputs in response to determining that the ETIC needs to operate with the high modulation bandwidth.
9. 9 . The ET power management circuit of claim 7 , wherein the control circuit is further configured to decouple the first ET voltage circuit and the second ET voltage circuit from the at least two auxiliary voltage outputs in response to determining that the ETIC needs to operate with the low modulation bandwidth.
10. 10 . The ET power management circuit of claim 7 , wherein the control circuit is further configured to determine whether the ETIC needs to operate with the high modulation bandwidth or the low modulation bandwidth based on any one of the first target voltage and the second target voltage.
11. 11 . The ET power management circuit of claim 10 , wherein the control circuit is further configured to determine whether the ETIC needs to operate with the high modulation bandwidth or the low modulation bandwidth based on a higher one of the first target voltage and the second target voltage.
12. 12 . The ET power management circuit of claim 7 , further comprising: a first voltage equalizer circuit coupled to the first ET voltage circuit and configured to equalize the first target voltage based on a first transfer function; and a second voltage equalizer circuit coupled to the second ET voltage circuit and configured to equalize the second target voltage based on a second transfer function.
13. 13 . The ET power management circuit of claim 12 , wherein the first transfer function and the second transfer function are each determined to offset a voltage disturbance caused by any one of the high-bandwidth power amplifier circuit and the at least two low-bandwidth power amplifier circuits.
14. 14 . The ET power management circuit of claim 7 , wherein the high-bandwidth power amplifier circuit comprises: a plus input stage and a plus output stage each coupled to a first one of the at least two auxiliary voltage outputs; and a minus input stage and a minus output stage each coupled to a second one of the at least two auxiliary voltage outputs.
15. 15 . The ET power management circuit of claim 14 , wherein the plus output stage and the minus output stage are coupled to a plus load capacitor and a minus load capacitor, respectively.
16. 16 . The ET power management circuit of claim 15 , wherein the at least two low-bandwidth power amplifier circuits each comprises an input stage and an output stage coupled to a respective one of the at least two primary voltage outputs.
17. 17 . The ET power management circuit of claim 16 , wherein the output stage is coupled to a load capacitor.
18. 18 . The ET power management circuit of claim 17 , wherein the plus load capacitor and the minus load capacitor are configured to each have a lower capacitance than the load capacitor to thereby cause the second equivalent capacitance to be lower than the first equivalent capacitance.

Description

RELATED APPLICATIONS This application is a 35 USC 371 national phase filing of International Application No. PCT/US2021/050892, filed Sep. 17, 2021, which claims the benefit of provisional patent application Ser. No. 63/114,185, filed Nov. 16, 2020, the disclosures of which are hereby incorporated herein by reference in their entireties. FIELD OF THE DISCLOSURE The present disclosure is related generally to an envelope tracking integrated circuit (ETIC), and particularly to an ETIC operable across a wide modulation bandwidth. BACKGROUND Mobile communication devices have become increasingly common in current society for providing wireless communication services. The prevalence of these mobile communication devices is driven in part by the many functions that are now enabled on such devices. Increased processing capabilities in such devices means that mobile communication devices have evolved from being pure communication tools into sophisticated mobile multimedia centers that enable enhanced user experiences. The redefined user experience requires higher data rates offered by wireless communication technologies, such as fifth-generation new-radio (5G-NR) technology configured to communicate a millimeter wave (mmWave) radio frequency (RF) signal(s) in an mmWave spectrum located above 12 GHz frequency. To achieve higher data rates, a mobile communication device may employ a power amplifier(s) to increase output power of the mmWave RF signal(s) (e.g., maintaining sufficient energy per bit). However, the increased output power of mmWave RF signal(s) can lead to increased power consumption and thermal dissipation in the mobile communication device, thus compromising overall performance and user experience. Envelope tracking (ET) is a power management technology designed to improve efficiency levels of power amplifiers to help reduce power consumption and thermal dissipation in mobile communication devices. In an ET system, a power amplifier(s) amplifies an RF signal(s) based on a time-variant ET voltage(s) generated in accordance with time-variant amplitudes of the RF signal(s). More specifically, the time-variant ET voltage(s) corresponds to a time-variant voltage envelope(s) that tracks (e.g., rises and falls) a time-variant power envelope(s) of the RF signal(s). Understandably, the better the time-variant voltage envelope(s) tracks the time-variant power envelope(s), the higher linearity the power amplifier(s) can achieve. However, the time-variant ET voltage(s) can be highly susceptible to distortions caused by trace inductance and/or load impedance, particularly when the time-variant ET voltage(s) is generated to track the time-variant power envelope(s) of a high modulation bandwidth (e.g., >200 MHz) RF signal(s). As a result, the time-variant voltage envelope(s) may become misaligned with the time-variant power envelope(s) of the RF signal(s), thus causing unwanted distortions (e.g., amplitude clipping) in the RF signal(s). In this regard, it is desirable to reduce distortions caused by trace inductance and/or load impedance in the time-variant ET voltage(s) across a wide modulation bandwidth. SUMMARY Embodiments of the disclosure relate to an envelope tracking (ET) integrated circuit (ETIC) operable across wide modulation bandwidth. The ETIC includes a primary voltage output(s) coupled to a low-bandwidth power amplifier circuit(s) and at least two auxiliary voltage outputs coupled to a high-bandwidth power amplifier circuit. In embodiments disclosed herein, the high-bandwidth power amplifier circuit has a lower equivalent capacitance, and thus a higher impedance resonance frequency, than the low-bandwidth power amplifier circuit(s). The ETIC also includes a pair of ET voltage circuits configured to generate a pair of ET voltages, respectively. To help mitigate potential distortion in the ET voltages, a control circuit is configured to couple the ET voltage circuits exclusively to the auxiliary voltage outputs when the ETIC needs to operate with a high modulation bandwidth (e.g., ≥200 MHz). Given the higher impedance resonance frequency of the high-bandwidth power amplifier circuit, it is possible to increase separation between an energy spectrum of a voltage disturbance, which is inherently caused by the high-bandwidth power amplifier circuit, and an energy spectrum of the high modulation bandwidth, thus helping to reduce the potential distortion in the ET voltages. In one aspect, an ETIC is provided. The ETIC includes at least two primary voltage outputs each coupled to a respective one of at least two low-bandwidth power amplifier circuits each having a first equivalent capacitance. The ETIC also includes at least two auxiliary voltage outputs coupled to a high-bandwidth power amplifier circuit having a second equivalent capacitance lower than the first equivalent capacitance. The ETIC also includes a first ET voltage circuit configured to generate a first ET voltage based on a first target voltage. The