FAST-SWITCHING POWER MANAGEMENT CIRCUIT AND RELATED APPARATUS

Abstract

A fast-switching power management circuit is provided. 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).

Claims

1. A fast-switching power management circuit comprising: a multi-level voltage circuit configured to generate a plurality of output voltages based on a supply voltage; a switch circuit coupled to the multi-level voltage circuit to receive the plurality of output voltages; and a control circuit configured to: determine an output voltage target; and 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.

2. The fast-switching power management circuit of claim 1 further comprising a second switch circuit coupled to the multi-level voltage circuit to receive the plurality of output voltages, wherein the control circuit is further configured to: determine a second output voltage target; and control the second switch circuit to output a lowest one of the plurality of output voltages that is greater than or equal to the second output voltage target.

3. The fast-switching power management circuit of claim 2 wherein the control circuit is further configured to receive the output voltage target and the second output voltage target from a transceiver circuit.

4. The fast-switching power management circuit of claim 2 further comprising a supply voltage circuit configured to generate the supply voltage based on a battery voltage.

5. The fast-switching power management circuit of claim 4 wherein the supply voltage circuit comprises a low-dropout (LDO) voltage regulator circuit.

6. The fast-switching power management circuit of claim 4 wherein the supply voltage circuit comprises an inductor-based direct-current (DC) to DC (DC-DC) voltage converter.

7. The fast-switching power management circuit of claim 4 wherein the control circuit is further configured to control the supply voltage circuit to adjust the supply voltage to minimize a difference between the supply voltage and the battery voltage.

8. The fast-switching power management circuit of claim 2 wherein: the multi-level voltage circuit is further configured to generate each of the plurality of output voltages from the supply voltage based on a respective one of a plurality of scaling factors; and each of the plurality of scaling factors is a function of a voltage ratio.

9. The fast-switching power management circuit of claim 8 wherein the control circuit is further configured to: dynamically determine the voltage ratio based on a higher one of the output voltage target and the second output voltage target; and dynamically adjust the plurality of scaling factors based on the determined voltage ratio.

10. A wireless communication apparatus comprising: a fast-switching power management circuit comprising: a multi-level voltage circuit configured to generate a plurality of output voltages based on a supply voltage; a switch circuit coupled to the multi-level voltage circuit to receive the plurality of output voltages; and a control circuit configured to: determine an output voltage target; and 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.

11. The wireless communication apparatus of claim 10 wherein the fast-switching power management circuit further comprises a second switch circuit coupled to the multi-level voltage circuit to receive the plurality of output voltages, wherein the control circuit is further configured to: determine a second output voltage target; and control the second switch circuit to output a lowest one of the plurality of output voltages that is greater than or equal to the second output voltage target.

12. The wireless communication apparatus of claim 11 further comprising: a first power amplifier circuit coupled to the switch circuit and configured to amplify a first radio frequency (RF) signal based on the one of the plurality of output voltages outputted by the switch circuit; and a second power amplifier circuit coupled to the second switch circuit and configured to amplify a second RF signal based on the one of the plurality of output voltages outputted by the second switch circuit.

13. The wireless communication apparatus of claim 12 wherein: the first RF signal is a Wi-Fi signal transmitted in a 2.4 GHz Industrial, Scientific, and Medical (ISM) band; and the second RF signal is a Wi-Fi signal transmitted in a 5 GHz ISM band.

14. The wireless communication apparatus of claim 11 wherein the control circuit is further configured to determine the output voltage target and the second output voltage target based on a target voltage signal received from a transceiver circuit.

15. The wireless communication apparatus of claim 11 wherein the fast-switching power management circuit further comprises a supply voltage circuit configured to generate the supply voltage based on a battery voltage.

16. The wireless communication apparatus of claim 15 wherein the supply voltage circuit comprises a low-dropout (LDO) voltage regulator circuit.

17. The wireless communication apparatus of claim 15 wherein the supply voltage circuit comprises an inductor-based direct-current (DC) to DC (DC-DC) voltage converter.

18. The wireless communication apparatus of claim 15 wherein the control circuit is further configured to control the supply voltage circuit to adjust the supply voltage to minimize a difference between the supply voltage and the battery voltage.

19. The wireless communication apparatus of claim 11 wherein: the multi-level voltage circuit is further configured to generate each of the plurality of output voltages from the supply voltage based on a respective one of a plurality of scaling factors; and each of the plurality of scaling factors is a function of a voltage ratio.

20. The wireless communication apparatus of claim 19 wherein the control circuit is further configured to: dynamically determine the voltage ratio based on a higher one of the output voltage target and the second output voltage target; and dynamically adjust the plurality of scaling factors based on the determined voltage ratio.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The accompanying drawings incorporated in and forming a part of this specification illustrate several aspects of the disclosure and, together with the description, serve to explain the principles of the disclosure.

[0010] FIG. 1 is a schematic diagram of an exemplary wireless communication apparatus including a conventional power management circuit;

[0011] FIG. 2 is a schematic diagram of an exemplary wireless communication apparatus including a fast-switching power management circuit configured according to embodiments of the present disclosure to adapt an output voltage(s) under a very short switching interval; and

[0012] FIG. 3 is schematic diagram of an exemplary multi-level voltage circuit that can be provided in the fast-switching power management circuit in FIG. 2 to simultaneously generate multiple output voltages.

DETAILED DESCRIPTION

[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.sub.CCA to a first power amplifier circuit 14A (denoted as “PA”) and a second output voltage V.sub.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.sub.CCA and the second power amplifier circuit 14B is configured to amplify a second RF signal 16B based on the second output voltage V.sub.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.sub.CCA at multiple voltage levels based on a supply voltage V.sub.SUP. The second multi-level voltage circuit 20B is configured to generate the second output voltage V.sub.CCB at multiple voltage levels based on the supply voltage V.sub.SUP. The conventional power management circuit 12 also includes a supply voltage circuit 22 configured to generate the supply voltage V.sub.SUP based on a battery voltage V.sub.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.sub.TGTA for the first power amplifier circuit 14A and a second target voltage V.sub.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.sub.CCA that is higher than or equal to the first target voltage V.sub.TGTA. Likewise, the control circuit 24 controls the second multi-level voltage circuit 20B to generate the second output voltage V.sub.CCB that is higher than or equal to the second target voltage V.sub.TGTB.

[0024] Notably, the first target voltage V.sub.TGTA and/or the second target voltage V.sub.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.sub.CCA and/or the second output voltage V.sub.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.sub.CCA and/or the second output voltage V.sub.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.sub.CCA and/or the second output voltage V.sub.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.sub.CCA and/or the second output voltage V.sub.CCB fast enough to keep pace with changes in the first target voltage V.sub.TGTA and/or the second target voltage V.sub.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.sub.CCA and/or a second output voltage V.sub.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.sub.CCA and/or the second output voltage V.sub.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.sub.CCA and/or the second output voltage V.sub.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.sub.out-1-V.sub.out-N based on a supply voltage V.sub.SUP. In a non-limiting example, the output voltages V.sub.out-1-V.sub.out-N are different from one another. By simultaneously generating the output voltages V.sub.out-1-V.sub.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.sub.out-1-V.sub.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.sub.out-1-V.sub.out-N at a voltage output 38A as the output voltage V.sub.CCA. Given that the output voltages V.sub.out-1-V.sub.out-N are concurrently available, the switch circuit 36A can flexibly couple any of the output voltages V.sub.out-1-V.sub.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.sub.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.sub.out-1-V.sub.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.sub.out-1-V.sub.out-N at a second voltage output 38B as the second output voltage V.sub.CCB. Given that the output voltages V.sub.out-1-V.sub.out-N are concurrently available, the second switch circuit 36B can flexibly couple any of the output voltages V.sub.out-1-V.sub.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.sub.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.sub.TGTA for the output voltage V.sub.CCA and control the switch circuit 36A to output a lowest one of the output voltages V.sub.out-1-V.sub.out-N that is greater than or equal to the output voltage target V.sub.TGTA at the voltage output 38A as the output voltage V.sub.CCA. In a non-limiting example, the control circuit 40 can receive the output voltage target V.sub.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.sub.TGTB for the second output voltage V.sub.CCB and control the second switch circuit 36B to output a lowest one of the output voltages V.sub.out-1-V.sub.out-N that is greater than or equal to the second output voltage target V.sub.TGTB at the second voltage output 38B as the second output voltage V.sub.CCB. In a non-limiting example, the control circuit 40 can receive the second output voltage target V.sub.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.sub.SUP based on a battery voltage V.sub.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.sub.SUP to minimize a difference (a.k.a. headroom) between the supply voltage V.sub.SUP and the battery voltage V.sub.BAT. For example, when a battery in the wireless communication apparatus 30 is fully charged, the battery voltage V.sub.BAT would be higher. As time goes by, the battery may be drained to cause the battery voltage V.sub.BAT to become lower. As such, if the supply voltage V.sub.SUP is maintained at a constant level, the difference between the supply voltage V.sub.SUP and the battery voltage V.sub.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.sub.SUP and the battery voltage V.sub.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.sub.out-1-V.sub.out-N from the supply voltage V.sub.SUP based on a respective one of a number of scaling factors f.sub.1-f.sub.N. In this regard, each of the output voltages V.sub.out-1-V.sub.out-N can be equal to the supply voltage V.sub.SUP multiplied by a respective one of the scaling factors f.sub.1-f.sub.N. For example, V.sub.out-1=V.sub.SUP*f.sub.1, V.sub.out-2=V.sub.SUP*f.sub.2, and V.sub.out-N=V.sub.SUP*f.sub.N. Each of the scaling factors f.sub.1-f.sub.N can be a function of a voltage ratio R.sub.V. For example, f.sub.1=(1+R.sub.V), f2=(1−R.sub.V), f.sub.N=(1+R.sub.V−R.sub.V). As such, the control circuit 40 can control the multi-level voltage circuit 34 to adjust the output voltages V.sub.out-1-V.sub.out-N by simply changing the voltage ratio R.sub.V.

[0035] Specifically, the control circuit 40 may dynamically determine the voltage ratio R.sub.V based on a higher one of the output voltage target V.sub.TGTA and the second output voltage target V.sub.TGTB. For example, if the output voltage target V.sub.TGTA at one time is higher than the second output voltage target V.sub.TGTB, the control circuit will determine the voltage ratio R.sub.V based on the output voltage target V.sub.TGTA. However, if the second output voltage target V.sub.TGTB becomes higher than the output voltage target V.sub.TGTA at another time, the control circuit will then determine the voltage ratio R.sub.V based on the second output voltage target V.sub.TGTB. By always determining the voltage ratio R.sub.V based on the higher one of the output voltage target V.sub.TGTA and the second output voltage target V.sub.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 f.sub.1-f.sub.N based on the determined voltage ratio R.sub.V.

[0036] In one non-limiting example, the output voltage target V.sub.TGTA is 5.0 V and the battery voltage V.sub.BAT is at 3.8 V. The control circuit 40 may set the voltage ratio R.sub.V to equal 0.5. As such, the scaling factors f.sub.1, f.sub.2, and f.sub.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.sub.out-1 at 5.0 V, the supply voltage V.sub.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.sub.out-2 will be 1.66 V (3.33 V*(1−0.5)=1.66 V) and the output voltage V.sub.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.sub.TGTA is 5.0 V and the battery voltage V.sub.BAT is at 2.8 V. The control circuit 40 may set the voltage ratio R.sub.V to equal 1. As such, the scaling factors f.sub.1, f.sub.2, and f.sub.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.sub.out-1 at 5.0 V, the supply voltage V.sub.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.sub.out-2 will be 0 V (2.5 V*(1−1)=0 V) and the output voltage V.sub.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.sub.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.sub.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.sub.out-1 and V.sub.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.sub.out-1-V.sub.out-N.

[0043] The multi-level voltage circuit 34A includes an input node 56 configured to receive the supply voltage V.sub.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.sub.out-1 and V.sub.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.sub.out-N at the supply voltage V.sub.SUP (V.sub.out-N=V.sub.sup) and the output voltage V.sub.out-1 at two times the supply voltage V.sub.SUP (V.sub.out-1=2*V.sub.SUP). As discussed earlier in FIG. 2, this is equivalent to setting the voltage ratio R.sub.V to 1.

[0045] To generate the output voltage V.sub.out-1 at 2*V.sub.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.sub.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.sub.out-1 can be outputted at 2*V.sub.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.