FAST-SWITCHING POWER MANAGEMENT CIRCUIT AND RELATED APPARATUS

[0001] The technology of the disclosure relates generally to power management in a wireless communication device.

[0002] Mobile communication devices have become increasingly common in current society. 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.

[0003] The redefined user experience requires higher data rates offered by wireless communication technologies, such as Wi-Fi, long-term evolution (LTE), and fifth-generation new-radio (5G-NR). To achieve the higher data rates in mobile communication devices, sophisticated power amplifiers may be employed to increase output power of radio frequency (RF) signals (e.g., maintaining sufficient energy per bit) communicated by mobile communication devices. However, the increased output power of RF signals can lead to increased power consumption and thermal dissipation in mobile communication devices, thus compromising overall performance and user experiences.

[0004] Average power tracking (APT) is a well-known power management technology designed to improve efficiency levels of power amplifiers to help reduce power consumption and thermal dissipation in a mobile communication device. In an APT system, a power management circuit is configured to provide an output voltage(s) to a power amplifier(s) based on an average power envelope of an RF signal(s) being amplified by the power amplifier(s). Notably, the average power envelope of the RF signal can change (e.g., increase or decrease) between frames or even symbols. As such, the power management circuit must be able to adapt the output voltage(s) on a per-frame or per-symbol basis. In this regard, the power management circuit must be able to adapt the output voltage(s) within a short switching interval (e.g., one microsecond) such that the power amplifier(s) can operate with optimal efficiency and linearity.

[0005] Aspects disclosed in the detailed description include a fast-switching power management circuit. The fast-switching power management circuit is configured to generate an output voltage(s) based on an output voltage target that may change on a per-frame or per-symbol basis. In embodiments disclosed herein, the fast-switching power management circuit can be configured to adapt (increase or decrease) the output voltage(s) within a very short switching interval (e.g., less than one microsecond). As a result, when the fast-switching power management circuit is employed in a wireless communication apparatus to supply the output voltage(s) to a power amplifier circuit(s), the fast-switching power management circuit can quickly adapt the output voltage(s) to help improve operating efficiency and linearity of the power amplifier circuit(s).

[0006] In one aspect, a fast-switching power management circuit is provided. The fast-switching power management circuit includes a multi-level voltage circuit configured to generate a plurality of output voltages based on a supply voltage. The fast-switching power management circuit also includes a switch circuit coupled to the multi-level voltage circuit to receive the plurality of output voltages. The fast-switching power management circuit also includes a control circuit. The control circuit is configured to determine an output voltage target. The control circuit is also configured to control the switch circuit to output a lowest one of the plurality of output voltages that is greater than or equal to the output voltage target.

[0007] In another aspect, a wireless communication apparatus is provided. The wireless communication apparatus includes a fast-switching power management circuit. The fast-switching power management circuit includes a multi-level voltage circuit configured to generate a plurality of output voltages based on a supply voltage. The fast-switching power management circuit also includes a switch circuit coupled to the multi-level voltage circuit to receive the plurality of output voltages. The fast-switching power management circuit also includes a control circuit. The control circuit is configured to determine an output voltage target. The control circuit is also configured to control the switch circuit to output a lowest one of the plurality of output voltages that is greater than or equal to the output voltage target.

[0008] Those skilled in the art will appreciate the scope of the disclosure and realize additional aspects thereof after reading the following detailed description in association with the accompanying drawings.

[0013] The embodiments set forth below represent the necessary information to enable those skilled in the art to practice the embodiments and illustrate the best mode of practicing the embodiments. Upon reading the following description in light of the accompanying drawing figures, those skilled in the art will understand the concepts of the disclosure and will recognize applications of these concepts not particularly addressed herein. It should be understood that these concepts and applications fall within the scope of the disclosure and the accompanying claims.

[0014] It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of the present disclosure. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.

[0015] It will be understood that when an element such as a layer, region, or substrate is referred to as being “on” or extending “onto” another element, it can be directly on or extend directly onto the other element or intervening elements may also be present. In contrast, when an element is referred to as being “directly on” or extending “directly onto” another element, there are no intervening elements present. Likewise, it will be understood that when an element such as a layer, region, or substrate is referred to as being “over” or extending “over” another element, it can be directly over or extend directly over the other element or intervening elements may also be present. In contrast, when an element is referred to as being “directly over” or extending “directly over” another element, there are no intervening elements present. It will also be understood that when an element is referred to as being “connected” or “coupled” to another element, it can be directly connected or coupled to the other element or intervening elements may be present. In contrast, when an element is referred to as being “directly connected” or “directly coupled” to another element, there are no intervening elements present.

[0016] Relative terms such as “below” or “above” or “upper” or “lower” or “horizontal” or “vertical” may be used herein to describe a relationship of one element, layer, or region to another element, layer, or region as illustrated in the Figures. It will be understood that these terms and those discussed above are intended to encompass different orientations of the device in addition to the orientation depicted in the Figures.

[0017] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes,” and/or “including” when used herein specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

[0018] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0019] Aspects disclosed in the detailed description include a fast-switching power management circuit. The fast-switching power management circuit is configured to generate an output voltage(s) based on an output voltage target that may change on a per-frame or per-symbol basis. In embodiments disclosed herein, the fast-switching power management circuit can be configured to adapt (increase or decrease) the output voltage(s) within a very short switching interval (e.g., less than one microsecond). As a result, when the fast-switching power management circuit is employed in a wireless communication apparatus to supply the output voltage(s) to a power amplifier circuit(s), the fast-switching power management circuit can quickly adapt the output voltage(s) to help improve operating efficiency and linearity of the power amplifier circuit(s).

[0020] Before discussing the fast-switching power management circuit according to the present disclosure, starting at FIG. 2, an overview of a conventional power management circuit is first provided with reference to FIG. 1.

[0021] FIG. 1 is a schematic diagram of an exemplary wireless communication apparatus 10 including a conventional power management circuit 12. The conventional power management circuit 12 is configured to provide a first output voltage V_CCA to a first power amplifier circuit 14A (denoted as “PA”) and a second output voltage V_CCB to a second power amplifier circuit 14B (also denoted as “PA”). The first power amplifier circuit 14A is configured to amplify a first radio frequency (RF) signal 16A based on the first output voltage V_CCA and the second power amplifier circuit 14B is configured to amplify a second RF signal 16B based on the second output voltage V_CCB. The wireless communication apparatus 10 includes a transceiver circuit 18 that provides the first RF signal 16A and the second RF signal 16B to the first power amplifier circuit 14A and the second power amplifier circuit 14B, respectively.

[0022] The conventional power management circuit 12 includes a first multi-level voltage circuit 20A and a second multi-level voltage circuit 20B. The first multi-level voltage circuit 20A is configured to generate the first output voltage V_CCA at multiple voltage levels based on a supply voltage V_SUP. The second multi-level voltage circuit 20B is configured to generate the second output voltage V_CCB at multiple voltage levels based on the supply voltage V_SUP. The conventional power management circuit 12 also includes a supply voltage circuit 22 configured to generate the supply voltage V_SUP based on a battery voltage V_BAT.

[0023] The conventional power management circuit 12 can include a control circuit 24, which may be communicatively coupled to the transceiver circuit 18 via an RF front-end (RFFE) bus 26. The control circuit 24 may receive a target voltage signal 28 that indicates a first target voltage V_TGTA for the first power amplifier circuit 14A and a second target voltage V_TGTB for the second power amplifier circuit 14B. Accordingly, the control circuit 24 controls the first multi-level voltage circuit 20A to generate the first output voltage V_CCA that is higher than or equal to the first target voltage V_TGTA. Likewise, the control circuit 24 controls the second multi-level voltage circuit 20B to generate the second output voltage V_CCB that is higher than or equal to the second target voltage V_TGTB.

[0024] Notably, the first target voltage V_TGTA and/or the second target voltage V_TGTB may change on a per-frame or even per-symbol basis. In this regard, the conventional power management circuit 12 needs to adapt the first output voltage V_CCA and/or the second output voltage V_CCB within a tight switching interval. For example, the first RF signal 16A and/or the second RF signal 16B can be a Wi-Fi signal. In this regard, the switching interval for the conventional power management circuit 12 to adapt the first output voltage V_CCA and/or the second output voltage V_CCB may be as short as sixteen microseconds (16 μs).

[0025] The 16 μs switching interval can be seen as an overall delay budget for a variety of delays associated with adapting the first output voltage V_CCA and/or the second output voltage V_CCB. For example, the 16 μs switching interval should include a time taken by the transceiver circuit 18 to generate the target voltage signal 28 and transmit the target voltage signal 28 to the control circuit 24 over the RFFE bus 26. In addition, the 16 μs switching interval should also include a processing delay at the control circuit 24. Furthermore, the 16 μs switching interval should further include a voltage change delay (ramp-up/ramp-down) at the first multi-level voltage circuit 20A and/or the second multi-level voltage circuit 20B. As a result, the conventional power management circuit 12 may not be able to adapt the first output voltage V_CCA and/or the second output voltage V_CCB fast enough to keep pace with changes in the first target voltage V_TGTA and/or the second target voltage V_TGTB, and thus can potentially compromise operating efficiency and linearity of the first power amplifier circuit 14A and/or the second power amplifier circuit 14B. Thus, it may be desirable to optimize the conventional power management circuit 12 to enable fast voltage switching within a voltage switching interval that can be as short as one (1) μs.

[0026] In this regard, FIG. 2 is a schematic diagram of an exemplary wireless communication apparatus 30 including a fast-switching power management circuit 32 configured according to embodiments of the present disclosure to adapt an output voltage V_CCA and/or a second output voltage V_CCB under a very short switching interval. In a non-limiting example, the fast-switching power management circuit 32 is capable of changing the output voltage V_CCA and/or the second output voltage V_CCB well under the desired 1 μs voltage switching interval (e.g., 0.5 μs). As such, the fast-switching power management circuit 32 can adapt the output voltage V_CCA and/or the second output voltage V_CCB on a per-frame or even per-symbol basis, thus making it possible for the wireless communication apparatus 30 to transmit RF signals at higher modulation bandwidth (e.g., >100 MHz) with improved Error Vector Magnitude (EVM), Voltage Standing Wave Ratio (VSWR), and battery life.

[0027] The fast-switching power management circuit 32 includes a multi-level voltage circuit 34 configured to simultaneously generate a number of output voltages V_out-1-V_out-N based on a supply voltage V_SUP. In a non-limiting example, the output voltages V_out-1-V_out-N are different from one another. By simultaneously generating the output voltages V_out-1-V_out-N, the fast-switching power management circuit 32 can significantly reduce ongoing voltage change delay at the multi-level voltage circuit 34 compared to the conventional power management circuit 12 in FIG. 1.

[0028] The fast-switching power management circuit 32 includes a switch circuit 36A coupled to the multi-level voltage circuit 34 to receive the output voltages V_out-1-V_out-N. The switch circuit 36A, which can include any number and type of switches configured according to any suitable topology, can be controlled to selectively output any one of the output voltages V_out-1-V_out-N at a voltage output 38A as the output voltage V_CCA. Given that the output voltages V_out-1-V_out-N are concurrently available, the switch circuit 36A can flexibly couple any of the output voltages V_out-1-V_out-N to the voltage output 38A with negligible switching delay, thus making it possible for the fast-switching power management circuit 32 to adapt the output voltage V_CCA under the desired 1 μs voltage switching interval. Further, by employing only one multi-level voltage circuit 34, the fast-switching power management circuit 32 may be implemented with a smaller footprint compared to the conventional power management circuit 12 in FIG. 1.

[0029] The fast-switching power management circuit 32 also includes a second switch circuit 36B coupled to the multi-level voltage circuit 34 to receive the output voltages V_out-1-V_out-N. The second switch circuit 36B, which can include any number and type of switches configured according to any suitable topology, can be controlled to selectively output any one of the output voltages V_out-1-V_out-N at a second voltage output 38B as the second output voltage V_CCB. Given that the output voltages V_out-1-V_out-N are concurrently available, the second switch circuit 36B can flexibly couple any of the output voltages V_out-1-V_out-N to the second voltage output 38B with negligible switching delay, thus making it possible for the fast-switching power management circuit 32 to adapt the second output voltage V_CCB under the desired 1 μs voltage switching interval.

[0030] The fast-switching power management circuit 32 can include a control circuit 40, which can be a field-programmable gate array (FPGA), as an example. The control circuit 40 is configured to determine an output voltage target V_TGTA for the output voltage V_CCA and control the switch circuit 36A to output a lowest one of the output voltages V_out-1-V_out-N that is greater than or equal to the output voltage target V_TGTA at the voltage output 38A as the output voltage V_CCA. In a non-limiting example, the control circuit 40 can receive the output voltage target V_TGTA from a transceiver circuit 42 over an RFFE bus 44 and control the switch circuit 36A via a control signal 46A.

[0031] Similarly, the control circuit 40 is also configured to determine a second output voltage target V_TGTB for the second output voltage V_CCB and control the second switch circuit 36B to output a lowest one of the output voltages V_out-1-V_out-N that is greater than or equal to the second output voltage target V_TGTB at the second voltage output 38B as the second output voltage V_CCB. In a non-limiting example, the control circuit 40 can receive the second output voltage target V_TGTA from the transceiver circuit 42 over the RFFE bus 44 and control the second switch circuit 36B via a second control signal 46B.

[0032] The fast-switching power management circuit 32 also includes a supply voltage circuit 48 configured to generate the supply voltage V_SUP based on a battery voltage V_BAT. In a non-limiting example, the supply voltage circuit 48 can include a low-dropout (LDO) voltage regulator circuit or an inductor-based direct-current (DC) to DC (DC-DC) voltage converter.

[0033] The control circuit 40 may be configured to control the supply voltage circuit 48, for example via a voltage adjustment signal 50, to adjust the supply voltage V_SUP to minimize a difference (a.k.a. headroom) between the supply voltage V_SUP and the battery voltage V_BAT. For example, when a battery in the wireless communication apparatus 30 is fully charged, the battery voltage V_BAT would be higher. As time goes by, the battery may be drained to cause the battery voltage V_BAT to become lower. As such, if the supply voltage V_SUP is maintained at a constant level, the difference between the supply voltage V_SUP and the battery voltage V_BAT will increase, which can result in potential power loss in the supply voltage circuit 48. In this regard, by minimizing the difference between the supply voltage V_SUP and the battery voltage V_BAT, it is possible to reduce power loss at the supply voltage circuit 48.

[0034] In a non-limiting example, the multi-level voltage circuit is configured to generate each of the output voltages V_out-1-V_out-N from the supply voltage V_SUP based on a respective one of a number of scaling factors f₁-f_N. In this regard, each of the output voltages V_out-1-V_out-N can be equal to the supply voltage V_SUP multiplied by a respective one of the scaling factors f₁-f_N. For example, V_out-1=V_SUP*f₁, V_out-2=V_SUP*f₂, and V_out-N=V_SUP*f_N. Each of the scaling factors f₁-f_N can be a function of a voltage ratio R_V. For example, f₁=(1+R_V), f2=(1−R_V), f_N=(1+R_V−R_V). As such, the control circuit 40 can control the multi-level voltage circuit 34 to adjust the output voltages V_out-1-V_out-N by simply changing the voltage ratio R_V.

[0035] Specifically, the control circuit 40 may dynamically determine the voltage ratio R_V based on a higher one of the output voltage target V_TGTA and the second output voltage target V_TGTB. For example, if the output voltage target V_TGTA at one time is higher than the second output voltage target V_TGTB, the control circuit will determine the voltage ratio R_V based on the output voltage target V_TGTA. However, if the second output voltage target V_TGTB becomes higher than the output voltage target V_TGTA at another time, the control circuit will then determine the voltage ratio R_V based on the second output voltage target V_TGTB. By always determining the voltage ratio R_V based on the higher one of the output voltage target V_TGTA and the second output voltage target V_TGTB, it is possible to make sure that the fast-switching power management circuit 32 can always supply a sufficient level output voltage. Accordingly, the control circuit 40 can thus dynamically adjust the scaling factors f₁-f_N based on the determined voltage ratio R_V.

[0036] In one non-limiting example, the output voltage target V_TGTA is 5.0 V and the battery voltage V_BAT is at 3.8 V. The control circuit 40 may set the voltage ratio R_V to equal 0.5. As such, the scaling factors f₁, f₂, and f_N will be 1.5 (1+0.5), 0.5 (1−0.5), and 1 (1+0.5−0.5), respectively. In this regard, for the multi-level voltage circuit 34 to generate the highest output voltage V_out-1 at 5.0 V, the supply voltage V_SUP needs to be 3.33 V (5.0 V/(1+0.5)=3.33 V). The voltage headroom in this case will be 0.47 V (3.8 V−3.33 V=0.47 V). Accordingly, the output voltage V_out-2 will be 1.66 V (3.33 V*(1−0.5)=1.66 V) and the output voltage V_out-N will be 3.33 V (3.33 V*(1+0.5−0.5)=3.33 V).

[0037] In another non-limiting example, the output voltage target V_TGTA is 5.0 V and the battery voltage V_BAT is at 2.8 V. The control circuit 40 may set the voltage ratio R_V to equal 1. As such, the scaling factors f₁, f₂, and f_N will be 2 (1+1), 0 (1−1), and 1 (1+1−1), respectively. In this regard, for the multi-level voltage circuit 34 to generate the highest output voltage V_out-1 at 5.0 V, the supply voltage V_SUP needs to be 2.5 V (5.0 V/(1+1)=2.5 V). The voltage headroom in this case will be 0.3 V (2.8 V−2.5 V=0.3 V). Accordingly, the output voltage V_out-2 will be 0 V (2.5 V*(1−1)=0 V) and the output voltage V_out-N will be 2.5 V (2.5 V*(1+1−1)=2.5 V).

[0038] The wireless communication apparatus 30 can include a first power amplifier circuit 52A (denoted as “PA”) coupled to the switch circuit 36A. The first power amplifier circuit 52A is configured to amplify a first RF signal 54A based on the output voltage V_CCA outputted by the switch circuit 36A. In a non-limiting example, the first RF signal 54A is a Wi-Fi signal transmitted in a 2.4 GHz Industrial, Scientific, and Medical (ISM) band. It should be appreciated that the first RF signal 54A can also be other type of signals, including but not limited to Long-Term Evolution (LTE) and Fifth-Generation New-Radio (5G-NR) signals to be transmitted in any licensed or unlicensed RF bands.

[0039] The wireless communication apparatus 30 can include a second power amplifier circuit 52B (denoted as “PA”) coupled to the second switch circuit 36B. The second power amplifier circuit 52B is configured to amplify a second RF signal 54B based on the second output voltage V_CCB outputted by the second switch circuit 36B. In a non-limiting example, the second RF signal 54B is a Wi-Fi signal transmitted in a 5 GHz ISM band. It should be appreciated that the second RF signal 54B can also be other type of signals, including but not limited to LTE and 5G-NR signals to be transmitted in any licensed or unlicensed RF bands.

[0040] Although the wireless communication apparatus 30 is shown to include only one of the fast-switching power management circuit 32 coupled to the first power amplifier circuit 52A and the second power amplifier circuit 54B, it should be appreciated that other configurations are also possible. In a non-limiting example, a second one of the fast-switching power management circuit 32 can be added to support additional power amplifier circuits. In an embodiment, one of the fast-switching power management circuit 32 can be collocated with an antenna(s) mounted on an upper edge of the wireless communication apparatus 30, while another one of the fast-switching power management circuit 32 can be collocated with another antenna(s) mounted on a lower edge of the wireless communication apparatus 30. Notably, such configuration can help mitigate interference caused by so-called “hand blocking effect” in the wireless communication apparatus 30.

[0041] FIG. 3 is schematic diagram of an exemplary multi-level voltage circuit 34A that can be provided in the fast-switching power management circuit 32 in FIG. 2 as the multi-level voltage circuit 34. Common elements between FIGS. 2 and 3 are shown therein with common element numbers and will not be re-described herein.

[0042] For the convenience of illustration, the multi-level voltage circuit 34A is shown to generate only the output voltages V_out-1 and V_out-N. It should be appreciated that the multi-level voltage circuit 34A can be configured to generate any number of the output voltages V_out-1-V_out-N.

[0043] The multi-level voltage circuit 34A includes an input node 56 configured to receive the supply voltage V_SUP. The multi-level voltage circuit 34A includes a first output node 58 and a second output node 60 configured to output the output voltage V_out-1 and V_out-N, respectively. The multi-level voltage circuit 18A includes a first switch SW1, a second switch SW2, a third switch SW3, and a fourth switch SW4. The first switch SW1 and the second switch SW2 are coupled in series between the input node 56 and the first output node 58. The third switch SW3 and the fourth switch SW4 are coupled in series between the input node 56 and the second output node 60. The multi-level voltage circuit 34A includes a fly capacitor 62A having one end coupled in between the first switch SW1 and the second switch SW2, and another end coupled in between the third switch SW3 and the fourth switch SW4.

[0044] In a non-limiting example, the multi-level voltage circuit 34A can be controlled to generate the output voltage V_out-N at the supply voltage V_SUP (V_out-N=V_sup) and the output voltage V_out-1 at two times the supply voltage V_SUP (V_out-1=2*V_SUP). As discussed earlier in FIG. 2, this is equivalent to setting the voltage ratio R_V to 1.

[0045] To generate the output voltage V_out-1 at 2*V_SUP, the first switch SW2 and the fourth switch SW4 are controlled to be closed, while the second switch SW2 and the third switch SW3 are controlled to be opened. As such, the fly capacitor 62A can be charged up to the supply voltage V_SUP. Subsequently, the first switch SW2 and the fourth switch SW4 are controlled to be opened, while the second switch SW2 and the third switch SW3 are controlled to be closed. Accordingly, the output voltage V_out-1 can be outputted at 2*V_SUP.

[0046] Those skilled in the art will recognize improvements and modifications to the embodiments of the present disclosure. All such improvements and modifications are considered within the scope of the concepts disclosed herein and the claims that follow.