Apparatus for power conversion

Abstract

An apparatus for power conversion is disclosed. The power converter includes an autotransformer, a first set of switches, and a second set of switches. The autotransformer includes a plurality of windings. The first set of switches is coupled between an input node and an output node of the power converter. The second set of switches is coupled between the reference potential and the output node. Further, the first set of switches is operable to control switching of a circuit path comprising a plurality of windings of the autotransformer. The second set of switches is operable to transfer current from the plurality of windings of the autotransformer through the second set of switches to the output node.

Description

Technical Field

[0001] The present invention relates to a device for power conversion. Background Art

[0002] Data centers are necessary for providing many services. The energy consumption of all data centers globally accounts for approximately 2% of the total energy usage. Therefore, data center providers are constantly seeking to improve the efficiency of power conversion in order to save energy or be able to increase the power of services such as CPUs / GPUs / ASICs in existing data centers. Machine learning and artificial intelligence require very powerful GPUs or custom-designed ASICs to meet the required computing power.

[0003] Today, most digital loads are directly powered from a 12VDC bus, using a single-stage multi-phase buck topology, namely the so-called voltage regulator module (VRM). However, as the power demand under digital loads increases, the conduction losses at the 12VDC bus are becoming an undesirable bottleneck. This has led to the proposal of a 48VDC architecture to supply power.

[0004] Operating the system using a 40V to 60VDC input voltage bus instead of a 12VDC bus has several advantages.

[0005] For example, the first stage of a conventional power converter is typically configured to step down a high input voltage (48 volts DC) to an intermediate voltage. This first stage can be an unregulated or regulated high-efficiency power converter and provides the step-down conversion of the input voltage to the intermediate voltage, which is input into a so-called intermediate bus power converter (IBC). The second stage can be based on a common buck converter with very good transient response and high efficiency. Summary of the Invention

[0006] The present disclosure includes the observation that the power conversion efficiency of a conventional switched capacitor converter can be improved. For example, to this end, the examples herein include novel ways of providing improved performance of a switched capacitor converter and the effective generation of a corresponding output voltage.

[0007] More specifically, according to one example, a device such as a power converter or other suitable entity as discussed herein includes an autotransformer, a first set of switches, and a second set of switches. The autotransformer includes a plurality of windings. The first set of switches is coupled between the input node and the output node of the device. The second set of switches is coupled between a reference potential and the output node. The first set of switches is operable to control the switching of a circuit path including the plurality of windings of the autotransformer; the second set of switches is operable to conduct current from the plurality of windings of the autotransformer through the second set of switches to the output node.

[0008] In one example, the current as described above is a first current. It should also be noted that the first set of switches can be configured to transfer a second current from the autotransformer through the first set of switches to the output node.

[0009] According to another example, the second set of switches includes a first pair of switches arranged in series and a second pair of switches arranged in series; the first pair of switches can be arranged in series between the reference potential and the output node; the second pair of switches can be arranged in series between the reference potential and the output node.

[0010] The current as discussed herein can include a first current and a second current. The first pair of switches can be configured to control the transfer of the first current from the multiple windings of the autotransformer to the output node; the second pair of switches can be configured to control the transfer of the second current from the multiple windings of the autotransformer to the output node.

[0011] According to another example, the input node of the device can be configured to supply an input voltage to the first set of switches. The first set of switches can be configured to include a first switch and a second switch; the first switch can be disposed between the input node and a first circuit path, the first circuit path including a first primary winding of the autotransformer; the second switch can be disposed between the input node and a second circuit path including a second primary winding of the autotransformer, the second primary winding being magnetically coupled to the first primary winding. The autotransformer can further include: a secondary winding that is magnetically coupled to both the first primary winding and the second primary winding; the first circuit path can extend between the first switch and a first node of the secondary winding of the autotransformer. The second circuit path extends between the second switch and a second node of the secondary winding of the autotransformer. The second set of switches can include a third switch and a fourth switch. The third switch can be coupled between the first node of the secondary winding and the output node, and the third switch can be configured to control the transfer of the first current in the current from the first node of the secondary winding to the output node. The fourth switch can be coupled between the second node of the secondary winding and the output node, and the fourth switch can be configured to control the transfer of the second current in the current from the second node of the secondary winding to the output node.

[0012] In addition, the apparatus discussed herein can be configured to include a controller operable to: for a first portion of a respective control period of a plurality of control periods: i) activate a first switch, the activation of the first switch being operable to transfer an input voltage from an input node through the first switch to a first circuit path, and ii) deactivate a second switch, the deactivation of the second switch being operable to prevent the transfer of the input voltage through the second switch to a second circuit path; and for a second portion of a respective control period of the plurality of control periods: i) deactivate the first switch, the deactivation of the first switch being operable to prevent the transfer of the input voltage through the first switch to the first circuit path, and ii) activate the second switch, the activation of the second switch being operable to transfer the input voltage from the input node through the second switch to the second circuit path.

[0013] Additionally, a first set of switches as discussed herein can include a fifth switch and a sixth switch. The fifth switch can be coupled to the first circuit path and the first switch; the sixth switch can be coupled to the second circuit path and the second switch.

[0014] The controller can be configured to: for a first portion of a control period, deactivate the fifth switch and activate the sixth switch, the activation of the sixth switch being operable to transfer a second current from the second circuit path through the sixth switch to an output node; and for a second portion of the control period, deactivate the sixth switch and activate the fifth switch, the activation of the fifth switch being operable to transfer a first current from the first circuit path through the fifth switch to the output node.

[0015] It should also be noted that the plurality of windings of an autotransformer can include a plurality of primary windings and secondary windings. A second set of switches can include a first switch and a second switch. The first switch can be directly coupled to a first node of the secondary winding, and the second switch can be directly coupled to a second node of the secondary winding. The currents as discussed herein can include a first current and a second current. The apparatus can further include a controller operable to switch between: i) in a first portion of a respective control period, activating the first switch to transfer the first current from the first node of the secondary winding through the first switch to the output node, and ii) in a second portion of the respective control period, activating the second switch to transfer the second current from the second node of the secondary winding through the second switch to the output node.

[0016] According to a further example, the second set of switches can include a third switch and a fourth switch. The third switch can be directly coupled to the first node of the secondary winding, the third switch can be directly coupled to the first switch and is arranged in series with the first switch. The fourth switch can be directly coupled to the second node of the secondary winding, the fourth switch can be directly coupled to the second switch and is arranged in series with the second switch.

[0017] Additionally, the controller can also be operable to: i) in the first part of a corresponding control period, activate a fourth switch, the activation of the fourth switch being operable to connect a second node of the secondary winding to a reference potential; and ii) in the second part of the corresponding control period, activate a third switch, the activation of the third switch being operable to connect a first node of the secondary winding to a reference potential.

[0018] According to another example, a device as discussed herein can be configured to include a plurality of capacitors, such as including a first capacitor and a second capacitor. The circuit paths can include a first resonant circuit path and a second circuit resonant path. The first resonant circuit path includes the first capacitor and a first primary winding of an autotransformer arranged in series. The second resonant circuit path includes the second capacitor and a second primary winding of the autotransformer arranged in series. The autotransformer can also include a secondary winding, the secondary winding including a first node and a second node. The first node can directly couple the first primary winding to the secondary winding, and the second node can be configured to directly couple the second primary winding to the secondary winding. The second set of switches can include a first switch and a second switch; the first switch can be coupled between the first node of the secondary winding and the output node; the second switch can be coupled between the second node of the secondary winding and the output node.

[0019] The autotransformer can be a matrix multi-tap autotransformer.

[0020] Furthermore, the autotransformer can include a first primary winding connected between the first node and the second node of the autotransformer. The autotransformer can include a secondary winding connected between the second node and the third node of the autotransformer. The autotransformer can include a second primary winding connected between the third node and the fourth node of the autotransformer. The second set of switches can include a first switch and a second switch. The current as described herein can include a first current and a second current. The first switch can be operable to control the transfer of the first current from the second node of the autotransformer through the first switch to the output node; the second switch can be operable to control the transfer of the second current from the third node of the autotransformer through the second switch to the output node.

[0021] According to a further example, a device as discussed herein can be configured to include a controller, the controller being operable to: for the first part of a control period: i) activate the first switch to a conducting state, ii) deactivate the second switch to a non-conducting state, and iii) directly couple the third node of the autotransformer to a reference potential; and for the second part of the control period: i) activate the second switch to a conducting state, ii) deactivate the first switch to a non-conducting state, and iii) directly couple the second node of the autotransformer to a reference potential.

[0022] According to another example, the apparatus may include: an autotransformer including a primary winding and a secondary winding; a plurality of switches including a first switch, a second switch, a third switch, and a fourth switch; a plurality of nodes including: i) a first node directly coupled to the first switch and the second switch connected in series, and ii) a second node directly coupled to the third switch and the fourth switch connected in series; wherein the secondary winding may be connected between the first node and the second node; and an output node operable to output an output current based on: i) a first output current supplied from the first node through the first switch, and ii) a second output current supplied from the second node through the third switch.

[0023] Additionally, the apparatus as discussed herein may be configured to include: a fifth switch and a sixth switch; wherein the first switch may be serially disposed between the fifth switch and the second switch; and wherein the third switch may be serially disposed between the sixth switch and the fourth switch.

[0024] Furthermore, the apparatus as discussed herein may be configured to include: a first circuit path extending between the fifth switch and the first node, the first circuit path including a first capacitor serially disposed with a first primary winding of the autotransformer; and a second circuit path extending between the sixth switch and the second node, the second circuit path including a second capacitor serially disposed with a second primary winding of the autotransformer.

[0025] Additionally, the apparatus as discussed herein may be configured to include a controller operable to: for a first portion of a control period: i) activate the first switch to a conducting state, ii) deactivate the third switch to a non-conducting state, and iii) activate the fourth switch to directly couple the second node to a reference voltage; and for a second portion of the control period: i) activate the third switch to a conducting state, ii) deactivate the first switch to a non-conducting state, and iii) activate the second switch to directly couple the first node to a reference voltage.

[0026] According to another example, the controller may be configured to: for a first portion of a control period: i) activate the sixth switch to a conducting state, ii) deactivate both the second switch and the fifth switch to non-conducting states; and for a second portion of the control period: i) activate the fifth switch to a conducting state, ii) deactivate both the fourth switch and the sixth switch to non-conducting states.

[0027] It should also be noted that the present disclosure also includes a method of manufacturing a power converter as described above. The method includes a manufacturer resource receiving an autotransformer including a plurality of windings. The manufacturer resource manufactures a power converter to include the autotransformer. Additionally, the manufacturer resource manufactures a power converter to include a first set of switches and a second set of switches. The first set of switches is operable to control the switching of a circuit path including a plurality of windings; the second set of switches is operable to transfer an output current from the autotransformer to an output node to power a load. Note that other possible method operations are discussed herein.

[0028] Accordingly, implementations as discussed herein are more useful than conventional techniques. For example, compared to conventional techniques, the novel power converter provides an efficient conversion of an input voltage to a corresponding output voltage. Examples such as those discussed herein provide lower energy losses during the generation of the corresponding output voltage.

[0029] These and other more specific examples are disclosed in more detail below.

[0030] Note that any resource as discussed herein can include one or more computerized devices, apparatuses, hardware, etc. that perform and / or support any or all of the method operations disclosed herein. In other words, one or more computerized devices or processors can be programmed and / or configured to operate as described herein to perform the different examples described herein.

[0031] Other examples herein include software programs for performing the steps and / or operations outlined above and disclosed in detail below. One such example includes a computer program product that includes a non-transitory computer-readable storage medium (i.e., any computer-readable hardware storage medium) on which software instructions are encoded for subsequent execution. When executed in a computerized device (hardware) having a processor, the instructions program the processor (hardware) and / or cause the processor (hardware) to perform the operations disclosed herein. Such an arrangement is typically provided as software, code, instructions, and / or other data (e.g., data structures) arranged or encoded on a non-transitory computer-readable storage medium such as an optical medium (e.g., CD-ROM), floppy disk, hard disk, memory stick, storage device, etc. or as firmware on other media such as one or more ROMs, RAMs, PROMs, etc. or is provided as an application-specific integrated circuit (ASIC), etc. The software or firmware or other such configuration can be installed onto the computerized device to cause the computerized device to perform the techniques described herein.

[0032] Accordingly, examples herein relate to methods, systems, computer program products, etc. that support the operations discussed herein.

[0033] One example includes a computer-readable storage medium and / or system having instructions stored thereon to facilitate generating an output voltage to power a load. When executed by computer processor hardware, the instructions cause the computer processor hardware (such as one or more processor devices or hardware located at the same or different locations) to control the operation of a power converter and corresponding switches to convert a respective input voltage into an output voltage for the power load.

[0034] For clarity, the order of the above steps has been added. Note that any processing steps discussed herein can be performed in any suitable order.

[0035] Other examples of the present disclosure include software programs and / or corresponding hardware for performing any of the method example steps and operations outlined above and disclosed in detail below.

[0036] It should be understood that the systems, methods, apparatuses, instructions on computer-readable storage media, etc., discussed herein can also be embodied strictly as a software program, firmware, a hybrid embodied as software, hardware, and / or firmware, or embodied as separate hardware, for example, within a processor (hardware or software), within an operating system, or within a software application.

[0037] It should also be noted that although the examples discussed herein are applicable to controlling the operation of a switched-capacitor converter, the concepts disclosed herein can be advantageously applied to any other suitable voltage converter topology.

[0038] Additionally, note that although each of the different features, techniques, configurations, etc., herein may be discussed in different places in the present disclosure, it is intended that each concept in the concepts can optionally be performed independently of each other or in combination with each other, where appropriate. Thus, one or more of the present inventions described herein can be implemented and observed in many different ways.

[0039] Additionally, note that this initial discussion of examples (brief description of examples) herein purposefully does not specify every example and / or incremental novel aspect of the present disclosure or the claimed invention. Instead, this brief description only presents general examples and corresponding points of novelty relative to conventional techniques. For additional details and / or possible perspectives (arrangements) of the invention, the reader is referred to the detailed description section of the present disclosure (which is a summary of the examples) and the corresponding drawings, further discussed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 is an example diagram showing a power supply including a switched-capacitor converter and an autotransformer as discussed herein.

[0041] Figure 2Is a more detailed diagram showing an example of a power converter as discussed herein.

[0042] Figure 3 Is an example timing diagram for controlling a power converter as discussed herein.

[0043] Figure 4 Is an example diagram of an autotransformer implemented in a power converter as described herein.

[0044] Figure 5 Is an example diagram of an autotransformer implemented in a power converter as discussed herein.

[0045] Figure 6 Is an example timing diagram showing the startup pulse width modulation switching frequency and duty cycle as discussed herein.

[0046] Figure 7 Is an example diagram showing a switched capacitor converter with a full - bridge rectifier as discussed herein.

[0047] Figure 8 Is an example timing diagram for controlling a power converter and corresponding signals as discussed herein.

[0048] Figure 9 Is an example diagram showing the operation of a power converter during a first duration as discussed herein.

[0049] Figure 10 Is an example diagram showing the operation of a power converter during a second duration as discussed herein.

[0050] Figure 11 Is an example diagram showing the operation of a power converter during a third duration as discussed herein.

[0051] Figure 12 Is an example diagram showing a computer architecture operable to perform one or more operations according to an example herein.

[0052] Figure 13 Is an example diagram showing a general method according to an example herein.

[0053] As shown in the accompanying drawings, the foregoing and other objects, features, and advantages of the examples herein will be apparent from the following more specific description herein, in which like reference numerals refer to the same parts throughout different views. The drawings are not necessarily to scale, but rather are emphasized to illustrate the examples, principles, concepts, etc. Detailed Description

[0054] According to one example, as further discussed herein, a device such as a power converter includes an autotransformer, a first set of switches, and a second set of switches. The autotransformer includes a plurality of windings. The first set of switches controls the switching of a circuit path including the plurality of windings of the autotransformer. The second set of switches controls the transfer of an output current from the plurality of windings of the autotransformer to an output node to supply power to a load.

[0055] Now, more specifically, Figure 1 is an example diagram showing a power supply including a switched capacitor converter as discussed herein.

[0056] As shown in this example, a power supply 100 (such as a device, an electronic device, etc.) includes a controller 140 and a power converter 135. The power converter 135 includes a primary 101, an autotransformer 160, and a secondary 102.

[0057] The primary 101 includes a first set of switches 125. The secondary 102 includes a second set of switches 126.

[0058] The autotransformer 160 includes a plurality of primary windings and at least one secondary winding. For example, the autotransformer 160 includes a primary winding 161-1 and a primary winding 161-2. The autotransformer 160 also includes a secondary winding 162.

[0059] Note that the multi-tap autotransformer 160 is shown by way of non-limiting example and may be instantiated as any suitable device, such as a transformer, a transformer device, a transformer apparatus, etc.

[0060] It should also be noted that each of the resources described herein can be instantiated in any suitable manner. For example, each of the controller 140, the power converter 135, the multi-tap autotransformer 160, etc. can be instantiated as or include hardware (such as circuitry), software (executable instructions), or a combination of hardware and software resources.

[0061] Note that the controller 140 and the corresponding operations can be implemented as controller software, controller hardware, or a combination of controller software and controller hardware.

[0062] During operation, the controller 140 generates a control signal 105 (such as one or more pulse width modulation signals), which controls the respective controlled states of the first set of switches 125 and the second set of switches 126 in the power converter 135.

[0063] As further shown, a power converter 135, such as a switched capacitor converter, receives an input voltage 121 (Vin, such as a DC input voltage) supplied from an input voltage source 120. As previously described, the multi-tap autotransformer 160 includes a first primary winding 161-1 and a second primary winding 161-2. In one example, the primary windings 161 are at least inductively coupled to the secondary winding 162 and are inductively coupled to each other. According to another example, the primary windings 161 are connected in series with the secondary winding 162.

[0064] As further discussed herein, a controller 140 of the power supply 100 controllably switches a plurality of capacitors and corresponding resonant circuit paths of the primary windings of a multi-tap autotransformer 160 (such as a matrix multi-tap autotransformer or other suitable type of component) to transfer energy from the input voltage (Vin) through the primary windings 161 to the secondary winding 162 to generate an output voltage 123 and a corresponding output current 122 to power a load 118.

[0065] Thus, an apparatus such as the power converter 135 described herein may be configured to include an autotransformer 160, a first set of switches 125, and a second set of switches 126. The autotransformer 160 includes a plurality of windings, such as a series connection of a first primary winding 161-1, a secondary winding 162, and a second primary winding 161-2. The first set of switches 125 may be configured to control the switching of a circuit path including a plurality of windings (such as the primary windings 161-1 and 161-2 of the autotransformer 160). The second set of switches 126 may be configured to control the transfer of the output voltage 123 and the corresponding output current 122 from one or more windings of the autotransformer 160 to an output node N23 to power the load 118.

[0066] As previously described, the plurality of windings of the autotransformer 160 may be configured to include a first primary winding 161-1, a second primary winding 161-2, and a secondary winding 162. Each of the plurality of windings in the autotransformer (such as the primary winding 161-1, the secondary winding 162, and the primary winding 161-2) is magnetically (inductively) coupled to each other. As further shown in this example, the secondary winding 162 is serially disposed between the first primary winding 161-1 and the second primary winding 161-2. For example, the primary winding 161-1 is connected between a node N41 and a node N51; the secondary winding 162 is connected between the node N51 and a node N52; the primary winding 161-2 is connected between the node N52 and a node N42.

[0067] The secondary winding 162 can be a single secondary winding of an autotransformer 162 that is serially disposed between a first primary winding 161-1 and a second primary winding 161-2. Each of the windings in the transformer 160 can be one or more windings that are parallely disposed.

[0068] Figure 2 is an example diagram showing a switched capacitor converter according to an example in this document.

[0069] As shown, the power supply 100 in this example includes an input voltage source 120 that supplies an input voltage 121 (Vin) to a node N1 of a power converter 135, for example.

[0070] The power converter 135 (a device such as hardware, circuitry, etc.) includes a plurality of switches Q1, Q2, Q3, Q4, Q5, Q6, Q7, and Q8 (such as field effect transistors or any other suitable type of switch) to control the transfer of current. Additionally, the power converter 135 includes a plurality of circuit components including a capacitor CRES1 and a capacitor CRES2.

[0071] As further shown, the power converter 135 includes a first resonant circuit path that includes a series connection of a capacitor CRES1 and a primary winding 161-1 serially connected between a node N11 and a node N51. Additionally, the power converter 135 includes a second resonant circuit path that includes a series connection of a capacitor CRES2 and a primary winding 161-2 serially connected between a node N12 and a node N52.

[0072] Furthermore, in this example, the windings in the multi-tap autotransformer 160 can include any number of turns. For example, the autotransformer 160 can be configured to include a primary winding 161-1 (such as N1 turns), a primary winding 161-2 (such as N1 turns), and a secondary winding 162 (such as N2 turns). Note that the number of windings (N1, N2, etc.) associated with the primary winding 161 and / or the secondary winding 162 can be any suitable value and can vary according to the example.

[0073] As further shown, switches Q1, Q2, Q3, and Q4 are serially connected between a node N1 (such as a node of a power supply 120 that supplies an input voltage 121) and a node N2 (such as a ground reference potential).

[0074] In addition, in this example, the drain node (D) of switch Q1 and the drain node (D) of switch Q5 are connected to the input voltage source Vin for node N1. Further, the source node (S) of switch Q1 is coupled to the drain node (D) of switch Q2 (node N11). The source node (S) of switch Q2 is coupled to the drain node (D) of switch Q3 (at node N21). The source node (S) of switch Q3 is coupled to the drain node (D) of switch Q4 (at the same node N31 as node PH1). Finally, the source node of switch Q4 is connected to node N2.

[0075] Capacitor CRES1 is connected between node N11 and the corresponding node N41 of primary winding 161-1. Capacitor CRES2 is connected between node N12 and the corresponding node N42 of primary winding 161-2.

[0076] The settings of capacitors CRES1 and CRES2 can be any suitable capacitance value. In one example, when the capacitance of CRES1 is equal to the capacitance of CRES2, the power converter 135 as described herein provides better performance, where the power converter 135 also operates well even when the capacitance of CRES1 is not equal to the capacitance of CRES2.

[0077] It should also be noted that the proposed hybrid switched-capacitor converter with a full-bridge rectifier (FB-HSC), such as power converter 135, can be configured to include an interleaved flying capacitor structure connected to a multi-tap autotransformer (MTA) for the full-bridge rectifier, as Figure 2 shown. Zero-voltage switching (ZVS) for all switches Q1 to Q8 can be achieved through the magnetizing inductance of autotransformer 160. Capacitor CRES1 is the first flying capacitor; capacitor CRES2 is the second flying capacitor.

[0078] Switches Q1 to Q8 can be divided into two groups of switches: the first group of switches is formed by Q1, Q3, Q6, and Q8 (control logic and control signal S1), and the second group of switches (Q2, Q4, Q5, and Q7) has PWM commands (control logic and control signal S2) that are 180° phase-shifted relative to the first group and have the same duty cycle. Power converter 135 can be configured to operate at a fixed duty cycle, such as approximately 50% or any other suitable value, to obtain a minimum RMS current.

[0079] The magnitude of the output voltage 123 depends on the multi-tap autotransformer turns ratio (N1 / N2). The value N1 represents the number of turns around each of primary windings 161-1 and 161-2. The value N2 represents the number of turns around secondary winding 162. The input voltage V in (121) and the output voltage V out(123) is given by the following Equation 1:

[0080]

[0081] In one example, the proposed FB-HSC (such as the power converter 135) itself can be scaled to different conversion ratios by simply designing different ratios between N1 and N2, which actually results in a new series of non-regulated hybrid dc-dc converters with different ratios (i.e., 3:1, 4:1, 5:1, 6:1, …).

[0082] In one example, the main feature of the proposed solution (such as the power converter 135) is to utilize the leakage inductance of the multi-tap autotransformer 160 to softly charge the resonant capacitors CRES1 and the resonant capacitor CRES2, which actually act as flying capacitors, enabling the use of switches with lower voltages (such as MOSFETs) on the primary side compared to, for example, the classical LLC (resonant power converter) topology. In this example of the power converter 135, the switches Q1, Q2, Q5, and Q6 block a part of the input voltage V in -V out .

[0083] Due to the full-bridge rectifier, the actual rectifier switches (Q3, Q4, Q7, and Q8) must block the output voltage V out . This is beneficial because “ultra”-low voltage FETs (such as the maximum voltage across the drain and source) can already be used in 6:1 implementations (i.e., 15V devices).

[0084] Another benefit of the power converter 135 as discussed herein is its symmetric behavior, which results in a reduction of the input voltage ripple.

[0085] One enabling factor for the high efficiency and high power density of the proposed FB-HSC (power converter 135) is the opportunity to use lower-rated voltage MOSFETs (such as field effect transistor devices with lower maximum rated voltages across the corresponding drain and source nodes) and the opportunity to implement class II ceramic capacitors such as for CRES1 and CRES2, which inherently provide high capacitance density. Additionally, the magnetizing inductance of the autotransformer 160 provides inductive energy to ensure ZVS transitions for all switches (such as field effect transistors (MOSFETs)).

[0086] Therefore, according to as Figure 2In the circuit shown, the power converter 135 includes a switch Q1 disposed between an input voltage source 120 and a first circuit path, such as a series circuit path including a capacitor CRES1 and a primary winding 161-1 of an autotransformer 161. The power converter 135 also includes a switch Q5 disposed between the input voltage source 120 (node N1) and a second circuit path, such as a series circuit path including a capacitor CRES2 and a primary winding 161-2 of the autotransformer 161.

[0087] As previously described, the primary winding 161-1, the secondary winding 162, and the primary winding 161-2 are magnetically coupled to each other. Thus, in such a case, the secondary winding 162 is magnetically coupled to both the first primary winding 161-1 and the second primary winding 161-2.

[0088] In addition, a first resonant circuit path, such as including a capacitor CRES1 and a primary winding 161-1, extends between a switch Q1 (and corresponding node N11) of the secondary winding 162 associated with the autotransformer 160 and a node N51; a second resonant circuit path, such as including a capacitor CRES2 and a primary winding 161-2, extends between a switch Q2 (and corresponding node N12) of the secondary winding 162 associated with the autotransformer 160 and a node N52.

[0089] In this example, the first set of switches 125 includes switches Q1, Q2, Q5, and Q6. The second set of switches 126 includes switches Q3, Q4, Q7, and Q8.

[0090] The combination of switch Q1, the first resonant circuit path (such as capacitor CRES1 and primary winding 161-1), and switch Q4 is disposed between node N1 and the input voltage source 120 and the ground reference node N2. The combination of switch Q5, the second resonant circuit path (such as capacitor CRES2 and primary winding 161-2), and switch Q8 is disposed between node N1 and the input voltage source 120 and the ground reference node N2.

[0091] As further shown, the controller generates a control signal 105-1. The control signal 105-1 is input to the respective gate nodes of switches Q1, Q3, Q6, and Q8. For example, the controller 140 supplies the control signal 105-1 (S1) to the gate nodes of switch Q1, switch Q3, switch Q6, and switch Q8.

[0092] The controller 140 generates a control signal 105-2. The control signal 105-2 is input to each of the gate nodes associated with switches Q2, Q4, Q5, and Q7. For example, the controller 140 supplies the control signal 105-2 (S2) to the gate nodes of switch Q2, the gate node of switch Q4, the gate node of switch Q5, and the gate node of switch Q7.

[0093] Figure 3 is an example timing diagram for controlling a power converter as discussed herein.

[0094] Generally, as shown in graph 300, the controller 140 generates a control signal 105-2 (also referred to as signal S2) that is the inverse of the control signal 105-1 (also referred to as signal S1). The pulse width of each control signal is approximately 49% or other suitable pulse width modulation value.

[0095] Between time T0 and time T1, when the control signal 105-1 (at a logic high level) controls the set of switches Q1, Q3, Q6, and Q8 to an on state (low impedance or short circuit between the corresponding drain and source nodes), the control signal 105-2 (logic low level) controls the set of switches Q2, Q4, Q5, and Q7 to an off state (extremely high impedance or open circuit between the corresponding drain and source nodes).

[0096] Conversely, between time T2 and time T3, when the control signal 105-2 (logic high level) controls the set of switches Q2, Q4, Q5, and Q7 to an on state, the control signal 105-1 (logic low level) controls the set of switches Q1, Q3, Q6, and Q8 to an off state.

[0097] Note that the duration between time T1 and time T2, the duration between time T3 and time T4, the duration between T5 and T6, etc. represent the so-called dead time during which each of the switches (Q1 to Q8) in the power converter 135 is deactivated to an off state.

[0098] As further shown, the control signal 105 is periodic. For example, the settings of the control signal 105 (control signal 105-1 and control signal 105-2) for subsequent cycles are the same as the settings for the cycle between time T0 and time T4. More specifically, the settings of the control signal 105 generated by the controller 140 between time T3 and time T7 are the same as the settings of the control signal 105 between time T0 and time T3, and so on.

[0099] In one example, the power converter 135 may be configured to operate in an unregulated manner.

[0100] In another example, the controller 110 controls the frequency of a control signal generated at any suitable frequency (the period is the time between T0 and time T4).

[0101] Additionally, as previously described, the controller 140 controls the pulse duration of the control signal 105 to be approximately 49% based on the dead time duration, although the control signal 105 can be generated with any suitable pulse width modulation value.

[0102] The magnitude of the output voltage 123 depends on the turns ratio (N1 / N2) of the multi-tap autotransformer 160.

[0103] Furthermore, in this example, the controller 140 generates a corresponding control signal 105 in each of a plurality of control cycles to convert the input voltage to the output voltage. This includes, via the controller 140, for the first part of the corresponding control cycle, such as between time T0 and time T1 of the plurality of control cycles: i) activating switch Q1, the activation of switch Q1 transmits the input voltage 121 received from the input voltage source 120 through switch Q1 to a first resonant circuit path including capacitor CRES1 and primary winding 161-1; and ii) deactivating switch Q5, the deactivation of switch Q5 prevents the input voltage from being transmitted through switch Q2 to a second resonant circuit path including capacitor CRES2 and primary winding 161-2.

[0104] The techniques herein also include, via the controller 140 (see also Figure 9 ), for the second part of the corresponding control cycle, such as between time T2 and time T3 of the plurality of control cycles: i) deactivating switch Q1, the deactivation of switch Q1 prevents the input voltage 121 from being transmitted through switch Q1 to the first resonant circuit path, and ii) activating switch Q5, the activation of switch Q5 transmits the input voltage 121 through switch Q5 of the second resonant circuit path.

[0105] Additionally, the controller 140 (see also Figure 9 and Figure 11 ) can be configured to: i) for the first part of the control cycle, such as between time T0 and time T1 in Figure 9 , deactivate switch Q2 and activate switch Q6, the activation of switch Q6 transmits the output current iout2 from node N42 of the transformer 160 (and the second resonant circuit path including winding 161-2 and capacitor CRES2) through switch Q6 to the output node N23; ii) for the second part of the control cycle, such as in Figure 11Between time T2 and time T3 therein, deactivate switch Q6 and activate switch Q2. Activation of switch Q2 is operable to transfer a second output current iout1 from node N41 of transformer 160 (and a first resonant circuit path including winding 161-1 and capacitor CRES1) to output node N23 through switch Q2.

[0106] Figure 4 is an example diagram of an autotransformer implemented in a power converter as described herein.

[0107] As Figure 4 shown, the multi-tap autotransformer 160 can be configured to include a plurality of windings, such as primary windings 161-1, primary winding 161-2, and secondary winding 162.

[0108] In this example, the windings of transformer 160 are wound around a magnetic core. The windings can be divided into two winding categories, such as a first category including primary windings 161-1 and primary winding 161-2 and a second category including secondary winding 162.

[0109] Considering the well-known convention of transformers, the "input winding" is considered the primary-side winding, and the "output winding" is considered the secondary winding. Based on this assumption, and if considering an ideal multi-tap autotransformer for a full-bridge rectifier, and considering that the magnetomotive force (MMF) is established by the current Isec through the secondary side and the corresponding secondary winding 162, then the MMF in the primary established by Iin1 (such as the current flowing through primary winding 161-1) and Iin2 (such as the current flowing through secondary winding 161-2) should be considered for calculation. In this scenario, the following equation 2 is valid:

[0110] N1 * Iin1 + N1 * Iin2 = N2 * Isec Equation 2

[0111] where N1 is equal to the number of turns of primary winding 161, and N2 is the number of turns of secondary winding 162.

[0112] To further improve the performance of the proposed power converter as discussed herein, an alternative instance of autotransformer 160 can be implemented via the matrix concept as Figure 5 shown. Note that Figure 5 the matrix scheme published in Figure 4 presents the same equivalent circuit as shown in

[0113] Figure 5 is an example diagram of an autotransformer implemented in any power converter as discussed herein.

[0114] Figure 5The autotransformer shown is a direct replacement for the autotransformer 160 in the power converter 135.

[0115] Taking into account the actual converter ratio, based on Equation 1 and Figure 5 the matrix MTA for the full - bridge rectifier scheme published in, the ratio between the input voltage V_in(121) and the output voltage V_out(123) is given by the following equation:

[0116] V_in / V_out = 2 + 4[M * n1 / n2] Equation 3

[0117] Furthermore, if a matrix - type multi - tap autotransformer array for a full - bridge rectifier is used: the n2x windings and the series - connected n1x windings can be arranged in parallel. By considering M as the number of windings connected in series for the input winding nN1x) and in parallel for the output winding n2x, the following equation provides the actual ratio between the input voltage V_in and the output voltage V_out:

[0118] V_in / V_out = 2 + 2 * [M * n1] / n2 Equation 4

[0119] The matrix scheme of the transformer 160 helps to utilize the horizontal direction of the substrate on which the windings are placed instead of the vertical direction (i.e., increasing the cost due to the number of layers).

[0120] Figure 6 is an example timing diagram showing the startup pulse - width modulation switching frequency and duty cycle as discussed herein.

[0121] When a voltage is applied to the input of the power converter 135, the system is in a charging state, and the value of the actual inrush current entering the converter 135 via the input voltage 121 depends on the impedance of the converter, which mainly exhibits capacitive behavior.

[0122] As shown in the timing diagram of the graph 600, note that the inrush current, such as the current entering node N1 at the startup of the power converter 135, may exceed the current capacity of the components, and the PCB (printed circuit board) traces the power converter 135, thus causing damage to one or more of those components. This problem can be solved and avoided by reducing the voltage rise time on the input of the power converter 135 (such as the input voltage 121) during the startup operation of the power converter 135.

[0123] Two different solutions can be adopted, such as: 1) voltage regulation at the input (using a buck converter) or 2) using a load switch. In either case, the amplitude of the input voltage 121 to the power converter 135 ramps up at a desired rate.

[0124] The two solutions mentioned above can help manage the inrush current from the input voltage source 120 to node N1 of the power converter 135. However, the management of inrush current may lead to an increase in the cost of the power supply because additional components may be required to achieve such a ramp-up of the input voltage. One way to ramp up the magnitude of the input voltage 121 supplied to the power converter 135 basically includes that the SR MOSFET can be clamped by the output voltage value, while the top FETs (such as switches Q1, Q2, Q5, Q6) face part or all of the input voltage during nominal operation (i.e., similar top MOSFET-class voltages with and without the electronic fuse).

[0125] The signal 610 in graph 600 indicates the corresponding switching frequency (FSW) of controlling the switches in the power converter 135 during startup (such as between time T61 and time T66). The signal 620 in graph 600 indicates the corresponding duty cycle of controlling the switches in the power converter 135 during startup (such as between time T61 to time T66). In Figure 6 where, FSW-MAX represents the maximum switching frequency, and FSW-NOM represents the nominal switching frequency, and FSW-MIN represents the minimum switching frequency, DUTY-MAX represents the maximum duty cycle, and DUTY-NOM represents the nominal duty cycle, and DUTY-MIN represents the minimum duty cycle.

[0126] Figure 7 is an example diagram showing a switched capacitor converter with a full-bridge rectifier as discussed herein.

[0127] In this example configuration of the power converter 135, Figure 7 shows the function of the corresponding zero-voltage-switching inductor Lzvs associated with the secondary winding 162.

[0128] Figure 8 is an example timing diagram for controlling a power converter as discussed herein.

[0129] In this example, as shown in graph 800. And as mentioned before, the controller 140 generates the corresponding control signal S1(105 - 1) and the control signal S2(105 - 2) to control the corresponding switches in the power converter 135.

[0130] The signal Icres1 represents the current through the series combination of the capacitor CRES1 and the primary winding 161 - 1 (the first resonant circuit path); Icres2 represents the current through the series combination of the capacitor CRES2 and the primary winding 161 - 2 (the second resonant circuit path).

[0131] Izvs represents the current through the inductor Lzvs associated with the secondary winding 162.

[0132] The signal iout1 (also known as Is1) represents the current supplied from node N21 to output node 123; the signal iout2 (also known as Is2) represents the current supplied from node N22 to output node 123.

[0133] Iout (the sum of current iout1 and current iout2) represents the total output current (Iout) supplied from node N23 to load 118.

[0134] Between time T0 and time T1, when the resonant circuit path including capacitor CRES1 and primary winding 161-1 is coupled to the input voltage via the activation of switch Q1, the corresponding activated switch Q3 supplies output current iout1 (the majority of the output current Iout) to generate current Iout. Conversely, between time T2 and time T3, when the resonant circuit path including capacitor CRES2 and primary winding 161-2 is coupled to the input voltage via the activation of switch Q5, the corresponding activated switch Q7 supplies output current iout2 (the majority of the output current Iout) to generate current Iout.

[0135] Figure 9 is an example diagram showing the operation of the power converter as discussed herein during a first duration (such as between time T0 and time T1).

[0136] As previously described, the controller 140 activates switches Q1, Q3, Q6, Q8 between time T0 and time T1. In one example, switches Q1, Q3, Q6, and Q8 turn on with zero voltage switching ZVS and zero current switching ZCS, during which a resonant current occurs between capacitor CRES1 and the leakage inductance of autotransformer 160, and another resonant current occurs between capacitor CRES2 and the leakage inductance of autotransformer 160. At this stage, such as between time T0 and time T1, capacitor CRES1 is softly charged from the input voltage V in source (such as via voltage 121), while capacitor CRES2 is softly discharged.

[0137] When the capacitance of capacitor CRES1 is equal to the capacitance of capacitor CRES2, the RMS (root mean square) current flowing through each of the capacitors is substantially the same. Considering the substantially balanced current amplitude between the resonant currents flowing through capacitor CRES1 and capacitor CRES2, the following equation holds:

[0138] Icres1(t) = -Icres2(t) and considering Icres1(t) = Ires(t), the two output currents can be written as:

[0139]

[0140] i out2 = i res

[0141] Therefore, the total output current is:

[0142] This equation represents the current multiplication factor of the power converter 135, since the input current is always equal to i res , the input current is multiplied by M and the input voltage is stepped down by M:

[0143]

[0144] Figure 10 is an example diagram showing the operation of the power converter as discussed herein during a second duration corresponding to the dead time (such as between time T1 and time T2 and between time T3 and T4).

[0145] For the duration between time T1 and time T2, in addition to deactivating switches Q2, Q4, Q5, Q7, the controller 140 also deactivates switches Q1, Q3, Q6, Q8. During this time, at t = t1, the inductive energy stored in L zvs inductor is used, and the energy stored in the parasitic capacitances associated with switches Q2, Q4, Q5, and Q7 is discharged to zero. When the energy stored in the capacitances associated with switches Q2, Q4, Q5, Q7 is discharged to zero, the corresponding body diodes associated with the switches start to conduct, thereby enabling ZVS turn-on thereafter. The topological state of the switches is as Figure 10 shown. The current enabling ZVS operation is represented as as Figure 8 shown, which is given by the following equation:

[0146]

[0147] For the duration between time T3 and time T4, in addition to deactivating switches Q1, Q3, Q6, and Q8, the controller 140 also deactivates switches Q2, Q4, Q5, and Q7. During this time, at t = t3, the inductive energy stored in L zvs inductor is used, and the energy stored in the parasitic capacitances associated with switches Q1, Q3, Q6, and Q8 is discharged to zero. When the energy stored in the capacitances associated with switches Q1, Q3, Q6, and Q8 is discharged to zero, the corresponding body diodes start to conduct, thereby enabling ZVS turn-on thereafter. The current enabling ZVS operation is

[0149] Figure 11is an example diagram showing the operation of a power converter and a third duration (such as between time T2 and time T3).

[0150] As previously mentioned, between time T2 and time T3, the controller activates switches Q2, Q4, Q5, Q7 to the on state in zero voltage switching (ZVS) and zero current switching (ZCS). A resonant current occurs (flows) between capacitor CRES1 and the leakage inductance of the multi-tap autotransformer 160, while another resonant current occurs (flows) between capacitor CRES2 and the leakage inductance of MTA 160. In this stage, capacitor CRES2 is softly charged from the input voltage source 120, while capacitor CRES1 is softly discharged. When the capacitance of capacitor CRES1 is equal to the capacitance of capacitor CRES2, the RMS current through each of the capacitors is substantially the same. During the balanced current of the resonant currents in C res1 and C res2 , we note that:

[0151] and considering the two output currents can be written as:

[0152]

[0153] i out1 =-i res

[0154] Therefore, the total output current is:

[0155] Since the input current is now the same conversion ratio M found previously is valid.

[0156] Therefore, the second set of switches 126 associated with the power converter 135 (see Figure 1 ) can be configured to include switch Q3 and switch Q7 and switch Q4 and switch Q8. Switch Q3, such as the corresponding drain node, is coupled to node N51 of the secondary winding 162. Switch Q7, such as the corresponding drain node, is coupled to node N52 of the secondary winding 162. The second set of switches 126 discussed herein may also include switch Q4 and switch Q8. As previously mentioned, switch Q4, such as the corresponding drain node, is coupled to node N51 of the secondary winding 162. Additionally, as previously mentioned, switch Q8, such as the corresponding drain node, is coupled to node N52 of the secondary winding 162.

[0157] In addition, as described above, the output current Iout includes the sum of the output current iout1 and the output current iout2. The controller is operable to switch between: i) in the first part of the respective control period, activating switch Q3 to transfer the output current iout1 from node N51 of the secondary winding 162 to the output node N23, and ii) in the second part of the respective control period, activating switch Q7 to transfer the output current iout2 from node N52 of the secondary winding 162 to the output node N23.

[0158] The controller 140 can be configured to: i) in the first part of the respective control period, such as between time T0 and time T1, activate switch Q8; the activation of switch Q8 connects node N52 of the secondary winding 162 to the ground reference voltage node N2; ii) in the second part of the respective control period, such as between time T2 and time T3, activate switch Q4, the activation of switch Q4 connects node N51 of the secondary winding 162 to the reference voltage node N2.

[0159] In another example herein, as described above, the autotransformer 160 includes a first primary winding 161-1 disposed between node N41 and node N51. Additionally, the autotransformer 160 includes a secondary winding 162 connected between node N51 and node N52. The autotransformer 160 includes a second primary winding 161-2 connected between node N52 of the autotransformer 160 and node N42.

[0160] As described above, the combination of the first primary winding 161-1, the secondary winding 162, and the second primary winding 161-2 are inductively coupled to each other.

[0161] In addition, as described above, the second set of switches 126 includes switch Q3 and switch Q4. Via the control signal S1 applied to switch Q3, the controller 140 controls the first output current iout1 to be transferred from node N51 of the autotransformer 160 through switch Q3 to the output node N23. Via the control signal S2 applied to switch Q7, the controller 140 controls the second output current iout2 to be transferred from node N52 of the autotransformer 160 through switch Q7 to the output node N23.

[0162] More specifically, for the first part of each control period, the controller 140: i) activates switch Q1 to the conducting state, ii) deactivates switch Q5 to the off state, and iii) activates switch Q8 to couple node N52 of the autotransformer 160 to the ground reference voltage node N2. For the second part of each control period, the controller 140: i) activates switch Q5 to the conducting state, ii) deactivates switch Q1 to the off state, and iii) activates switch Q4 to couple node N51 of the autotransformer 160 to the ground reference voltage node N2.

[0163] Accordingly, a first set of switches (such as switch Q2 and switch Q6) can be configured to transfer currents iout1 and iout2 from the transformer 160 to the output node N23. A second set of switches (such as switch Q3 and Q7) can be configured to transfer currents iout1 and iout2 from the transformer 162 to the node N23.

[0164] Figure 12 is an example block diagram of a computer system for implementing any of the previously discussed operations according to an embodiment herein.

[0165] Any resource discussed herein (such as the controller 140, the voltage converter 135, the switched capacitor converter 131, etc.) can be configured to include computer processor hardware and / or corresponding executable instructions to perform different operations discussed herein.

[0166] As shown, the computer system 1000 of this example includes an interconnect 1011 that provides a coupling of a computer-readable storage medium 1012 such as a non-transitory type of medium (which can be any suitable type of hardware storage medium in which digital information can be stored and retrieved), a processor 1013 (computer processor hardware), an I / O interface 1014, and a communication interface 1017. The computer-readable storage medium can be computer-readable storage hardware.

[0167] The computer-readable storage medium 1012 can be any hardware storage device, such as a memory, an optical storage, a hard disk drive, a floppy disk, etc. In one embodiment, the computer-readable storage medium 1012 stores instructions and / or data.

[0168] As shown, the computer-readable storage medium 1012 can be encoded with a controller application 140-1 (e.g., including instructions) to perform any of the operations discussed herein.

[0169] During operation of one embodiment, the processor 1013 accesses the computer-readable storage medium 1012 via the use of the interconnect 1011 in order to initiate, run, execute, interpret, or otherwise perform the instructions in the controller application 140-1 stored on the computer-readable storage medium 1012. Execution of the controller application 140-1 results in a controller process 140-2 to perform any operations and / or processing as discussed herein.

[0170] Those skilled in the art will understand that the computer system 1050 may include other processes and / or software and hardware components, such as an operating system that controls the allocation and use of hardware resources to execute the controller application 140-1.

[0171] According to different embodiments, note that the computer system may reside in any one of a variety of types of devices, including but not limited to power supplies, switched-capacitor converters, power converters, mobile computers, personal computer systems, wireless devices, wireless access points, base stations, telephone devices, desktop computers, laptop computers, notebook computers, netbook computers, mainframe computer systems, handheld computers, workstations, network computers, application servers, storage devices, consumer electronic devices (such as imaging devices, cameras, set-top boxes, mobile devices, video game consoles, handheld video game devices), peripheral devices (such as switches, modems, routers, set-top boxes), content management devices, handheld remote control devices, any type of computing or electronic device, etc. The computer system 1050 may reside anywhere or may be included in any suitable resource in any network environment to implement the functions as discussed herein.

[0172] Now the functions supported by different resources will be discussed via Figure 13 the flowcharts in. Note that the steps in the following flowcharts may be executed in any suitable order.

[0173] Figure 13 FIG. 1300 is a flowchart showing an example method according to an embodiment herein. Note that there will be some overlap with the concepts described above.

[0174] In processing operation 1310, the controller 140 controls the switching of the circuit path via the generation of control signals 105-1 and 105-2. The circuit path includes multiple windings of the autotransformer 160.

[0175] In processing operation 1320, the controller 140 controls a second set of switches. The controller 140 controls the second set of switches to transfer the output current and the corresponding output voltage from the multiple windings of the autotransformer to the output node to supply power to the load.

[0176] Again, it should be noted that the techniques herein are well suited for use in power supply applications. However, it should be noted that the embodiments herein are not limited to use in such applications, and the techniques discussed herein are also well suited for other applications.

[0177] Although the present invention has been specifically shown and described with reference to preferred embodiments thereof, those skilled in the art will understand that various changes in form and detail may be made therein without departing from the spirit and scope of the present application as defined by the appended claims. Such variations are intended to be covered by the scope of the present application. Accordingly, the foregoing description of embodiments of the present application is not intended to be limiting. Rather, any limitations of the present invention are presented in the appended claims.

Claims

1. A device for power conversion, comprising: An autotransformer including a plurality of windings; a first set of switches coupled between the input node and the output node; a second set of switches coupled between a reference potential and the output node; wherein the first set of switches is operable to control switching of a circuit path including a plurality of windings of the autotransformer; and The second set of switches is operable to transfer current from the plurality of windings of the autotransformer to the output node through the second set of switches.

2. The device according to claim 1, wherein: The second set of switches includes a first pair of switches arranged in series and a second pair of switches arranged in series; wherein the first pair of switches are arranged in series between the reference potential and the output node; and Wherein, the second pair of switches are arranged in series between the reference potential and the output node.

3. The device according to claim 2, wherein: The current includes a first current and a second current; wherein the first pair of switches is operable to control the transfer of the first current from the plurality of windings of the autotransformer to the output node; and Wherein, the second pair of switches is operable to control the transmission of the second current from the plurality of windings of the autotransformer to the output node.

4. The device according to claim 1, wherein: The input node supplies an input voltage to the first set of switches; Wherein, the first group of switches includes a first switch and a second switch; wherein the first switch is disposed between the input node and a first circuit path, the first circuit path comprising a first primary winding of the autotransformer; wherein the second switch is disposed between the input node and a second circuit path including a second primary winding of the autotransformer, the second primary winding being magnetically coupled to the first primary winding; wherein the autotransformer comprises a secondary winding magnetically coupled to both the first primary winding and the second primary winding; wherein the first circuit path extends between the first switch and a first node of the secondary winding of the autotransformer; wherein the second circuit path extends between the second switch and a second node of the secondary winding of the autotransformer; Wherein, the second group of switches includes a third switch and a fourth switch; wherein the third switch is coupled between the first node of the secondary winding and the output node, and the third switch is operable to control the transmission of a first current among the currents from the first node of the secondary winding to the output node; and The fourth switch is coupled between the second node of the secondary winding and the output node, and the fourth switch is operable to control the transmission of a second current among the currents from the second node of the secondary winding to the output node.

5. The apparatus according to claim 4, further comprising: A controller operable to: for a first portion of a corresponding control cycle of a plurality of control cycles: i) activating the first switch, activating the first switch being operable to transfer the input voltage from the input node through the first switch to the first circuit path, and ii) deactivating the second switch, deactivating the second switch being operable to prevent transfer of the input voltage through the second switch to the second circuit path; as well as For a second portion of a corresponding control cycle in the plurality of control cycles: i) deactivating the first switch, wherein deactivating the first switch is operable to prevent the input voltage from being transmitted to the first circuit path through the first switch, and ii) activating the second switch, wherein activating the second switch is operable to transmit the input voltage from the input node to the second circuit path through the second switch.

6. The device according to claim 5, wherein: The first set of switches also includes a fifth switch and a sixth switch; wherein the fifth switch is coupled to the first circuit path and the first switch; and The sixth switch is coupled to the second circuit path and the second switch.

7. The device according to claim 6, wherein: The controller is also operable to: for a first portion of the control cycle, deactivating the fifth switch and activating the sixth switch, the activation of the sixth switch being operable to transfer the second current from the second circuit path through the sixth switch to the output node; as well as For a second portion of the control cycle, the sixth switch is deactivated and the fifth switch is activated, the activation of the fifth switch being operable to transfer the first current from the first circuit path through the fifth switch to the output node.

8. The device according to claim 1, wherein: The plurality of windings of the autotransformer include a plurality of primary windings and secondary windings; The second switch group includes a first switch and a second switch, the first switch is directly coupled to a first node of the secondary winding, and the second switch is directly coupled to a second node of the secondary winding; Wherein, the current includes a first current and a second current, and the device further includes: A controller operable to switch between: i) activating the first switch to transfer the first current from a first node of the secondary winding to the output node through the first switch during a first portion of a corresponding control cycle, and ii) activating the second switch to transfer the second current from a second node of the secondary winding to the output node through the second switch during a second portion of the corresponding control cycle.

9. The device according to claim 8, wherein: The second set of switches also includes a third switch and a fourth switch; wherein the third switch is directly coupled to the first node of the secondary winding, the third switch is directly coupled to the first switch and is arranged in series with the first switch; and The fourth switch is directly coupled to the second node of the secondary winding, and the fourth switch is directly coupled to the second switch and is arranged in series with the second switch.

10. The device according to claim 9, wherein: The controller is also operable to: i) activating the fourth switch during a first portion of the respective control cycle, the activation of the fourth switch being operable to connect the second node of the secondary winding to the reference potential; as well as ii) activating the third switch during a second portion of the respective control cycle, the activation of the third switch being operable to connect the first node of the secondary winding to the reference potential.

11. The apparatus according to claim 1, further comprising: a plurality of capacitors including a first capacitor and a second capacitor; wherein the circuit path comprises a first resonant circuit path and a second resonant circuit path, the first resonant circuit path comprises the first capacitor and the first primary winding of the autotransformer arranged in series, and the second resonant circuit path comprises the second capacitor and the second primary winding of the autotransformer arranged in series; wherein the autotransformer comprises a secondary winding, the secondary winding comprises a first node and a second node, the first node directly couples the first primary winding to the secondary winding, and the second node directly couples the second primary winding to the secondary winding; and The second group of switches includes a first switch and a second switch, the first switch is coupled between a first node of the secondary winding and the output node, and the second switch is coupled between a second node of the secondary winding and the output node.

12. The device according to claim 1, wherein: The autotransformer is a matrix type multi-tap autotransformer.

13. The device according to claim 1, wherein: The autotransformer includes a first primary winding connected between a first node and a second node of the autotransformer; Wherein, the autotransformer comprises a secondary winding connected between a second node and a third node of the autotransformer; Wherein, the autotransformer comprises a second primary winding connected between a third node and a fourth node of the autotransformer; Wherein, the second group of switches includes a first switch and a second switch; Wherein, the current includes a first current and a second current; wherein the first switch is operable to control the transfer of the first current from the second node of the autotransformer through the first switch to the output node; and The second switch is operable to control transmission of the second current from a third node of the autotransformer to the output node through the second switch.

14. The apparatus according to claim 13, further comprising: A controller operable to: For a first part of a control cycle: i) activating the first switch to an on-state, ii) deactivating the second switch to an off-state, and iii) coupling a third node of the autotransformer directly to the reference potential; as well as For a second part of the control cycle: i) the second switch is activated to an on-state, ii) the first switch is deactivated to an off-state, and iii) a second node of the autotransformer is coupled directly to the reference potential.

15. The device according to claim 1, wherein: The current is a first current; as well as The first set of switches is operable to transfer a second current from the autotransformer to the output node through the first set of switches.

16. An apparatus for power conversion, comprising: An autotransformer including a primary winding and a secondary winding; a plurality of switches including a first switch, a second switch, a third switch and a fourth switch; a plurality of nodes, including: i) a first node directly coupled to the first switch and the second switch connected in series, and ii) a second node directly coupled to the third switch and the fourth switch connected in series; wherein the secondary winding is connected between the first node and the second node; and An output node operable to output an output current based on: i) a first output current supplied from the first node through the first switch, and ii) a second output current supplied from the second node through the third switch.

17. The apparatus according to claim 16, further comprising: a fifth switch and a sixth switch; Wherein, the first switch is arranged in series between the fifth switch and the second switch; and Wherein, the third switch is arranged in series between the sixth switch and the fourth switch.

18. The apparatus according to claim 17, further comprising: a first circuit path extending between the fifth switch and the first node, the first circuit path comprising a first capacitor arranged in series with a first primary winding of the autotransformer; as well as A second circuit path extends between the sixth switch and the second node, the second circuit path including a second capacitor arranged in series with the second primary winding of the autotransformer.

19. The apparatus according to claim 18, further comprising: A controller operable to: For a first portion of a control cycle: i) activating the first switch to an on state, ii) deactivating the third switch to an off state, and iii) activating the fourth switch to directly couple the second node to a reference voltage; as well as For a second portion of the control cycle: i) the third switch is activated to an on-state, ii) the first switch is deactivated to an off-state, and iii) the second switch is activated to couple the first node directly to the reference voltage.

20. The device according to claim 19, wherein The controller is also operable to: For a first portion of the control cycle: i) activating the sixth switch to an on state, ii) deactivating both the second switch and the fifth switch to an off state; as well as For a second portion of the control cycle: i) the fifth switch is activated to an on-state, ii) both the fourth switch and the sixth switch are deactivated to an off-state.

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