Active switch leakage current bypass

Abstract

The power supply component comprises a supply node for providing a supply voltage and a supply line for providing a source voltage. The supply line comprises a source node having a source voltage, and the supply line includes a supply line switch coupled between the source node and the supply node, the supply line switch coupling the source voltage to the supply node when the supply line switch is closed. The current bypass component diverts leakage current away from one or both of the source node and the supply node when the supply line switch is open.

Description

【Technical Field】 【0001】 The present disclosure generally relates to power sources. More specifically, the present disclosure relates to leakage current management within a power source. 【Background Art】 【0002】 A pulsed electric field (PEF) generator is a type of power source configured to generate an output waveform suitable for various applications. Generally, a PEF generator produces short intense bursts of electric field pulses, which are used to apply a high voltage electric field to various substances or materials over a short time period. PEF generators have many possible applications. They can be used in the food industry to inactivate bacteria, yeasts, and molds in food products, and thus extend their shelf life. They can be used in water and wastewater treatment to decompose contaminants. They can be used in biotechnology to assist in transferring genes into cells. These are only some of the many possible applications of PEF generators. 【0003】 Another example of a possible use of a PEF generator is in medical applications. In one such application, a PEF generator is incorporated into a medical device known as an electroporator for use in cancer treatment. The PEF generator of the electroporator generates a pulsed output waveform with an amplitude ranging from 5 V to 3 kV depending on the treatment. The pulsed voltage waveform generated by the electroporator is applied to a cancer tumor, inducing the biological phenomenon of electroporation and ultimately inducing tumor death. A PEF generator of this nature can be rated for extremely high peak power levels of 150 kW. 【0004】 The voltage range and high power associated with PEF generators pose many challenges in providing a clean and safe power output. 【Summary of the Invention】 【Means for Solving the Problems】 【0005】 One aspect of the present disclosure is a power supply component comprising a supply node for providing a supply voltage and a supply line, wherein the supply line comprises a source node having a source voltage and a supply line switch coupled between the source node and the supply node, the supply line switch comprising a supply line switch that, when the supply line switch is closed, couples the source voltage to the supply node, and a current bypass component that, when the supply line switch is open, causes leakage current to be bypassed away from one or both of the source node and the supply node. 【0006】 Another aspect of the present disclosure is a method, the method comprising coupling a source voltage to a supply node via a switch on a supply line and applying the source voltage to the supply node; opening the switch and discoupling the source voltage from the supply node; and diverting the leakage current away from one or both of the source node and the supply node while the switch is open. 【0007】 These and other aspects of this disclosure will be depicted in and become apparent in the accompanying drawings and descriptions. [Brief explanation of the drawing] 【0008】 [Figure 1] Figure 1 is a block diagram illustrating an embodiment of a power supply component. 【0009】 [Figure 2] Figure 2 is a block diagram illustrating another embodiment of the power supply component. 【0010】 [Figure 3] Figure 3 is a flowchart illustrating a method that may be described in detail in relation to embodiments disclosed herein. 【0011】 [Figure 4] Figure 4 is a block diagram depicting yet another embodiment of a power supply component. 【0012】 [Figure 5] Figure 5 depicts an example of a power supply source topology and leakage current. 【0013】 [Figure 6] Figure 6 depicts an additional example of the power supply source topology and leakage current of Figure 5. 【0014】 [Figure 7] Figure 7 depicts a power supply source that utilizes an example of the power supply component depicted in Figures 1 and 2. 【0015】 [Figure 8] Figure 8 is a simplified depiction of the power supply source of Figure 7 that depicts a side of the current bypass. 【0016】 [Figure 9] Figure 9 depicts an example of a current bypass component. 【0017】 [Figure 10] Figure 10 is a timing diagram illustrating the operation of the current bypass component of Figure 9. 【0018】 [Figure 11] Figure 11 is a graph illustrating an example of a pulse train that can be achieved using the power supply source disclosed herein. 【0019】 [Figure 12] Figure 12 is a block diagram of a computing system that can be utilized in connection with the embodiments disclosed herein. 【Mode for Carrying Out the Invention】 【0020】 Detailed explanation First, referring to FIG. 1, what is shown is a block diagram depicting an exemplary power supply component. As shown, supply node 102 is provided to apply a supply voltage, which can be used within a power supply source to provide a desired voltage. Also shown is a supply line 104 including a source node 106 having a source voltage V1 and a supply line switch 108 coupled between the source node 106 and the supply node 102. The supply line switch 108 couples the source voltage to the supply node 102 when the supply line switch 108 is closed. Additionally, the supply line 104 includes a current bypass component 110 for diverting leakage current away from one or both of the source node 106 and the supply node 102 when the supply line switch 108 is open. As shown in FIG. 1, the current bypass component 110 can be coupled between the supply node 102 and a bypass node 112. The bypass node 112 can be coupled to a ground terminal or another node (e.g., at a lower potential than the supply node 102). 【0021】 Referring to FIG. 2, what is shown is a block diagram depicting another embodiment of a power supply component. As shown, the supply line switch includes a set of 22 or more series switches 108, and the current bypass component 110 is coupled to a common node 214 between two series switches 108. In this variant, the current bypass component 110 is coupled between the common node 214 (between two series switches) and a bypass terminal 112. The series switches 108 can be implemented by semiconductor switches such as, for example, but not limited to, field effect transistors and / or insulated gate bipolar transistors. 【0022】 With reference to Figures 1 and 2, Figure 3 is also referenced, which is a flowchart illustrating a method that may be detailed in relation to the power supply components depicted in Figure 1. As shown, the source voltage V1 is coupled to the supply node 102 via a supply line switch (which may include one or more series switches 108) and applies the source voltage V1 to the supply node 102 (block 302). During operation, the supply line switch is opened, discouples the source voltage from the supply node 102 (block 304), and while the supply line switch is open, leakage current is diverted (via a current bypass component) away from one or both of the source node 106 and the supply node 102 (block 306). 【0023】 As shown in Figure 2, coupling in block 302 may include coupling the source voltage to the supply node 102 via at least two series switches 108, and in these variations, bypassing in block 306 may include bypassing the leakage current away from node 214 between the switches 108 to bypass node 112. As discussed above, the leakage current may be bypassed away from node 214 between two of the switches 108 to the ground terminal. 【0024】 The source voltage applied to the supply node 102 can be used for various purposes. For example, as further described herein, the selected source voltage may be used as a rail voltage applied to a bridge circuit, which may be used to generate a time-varying waveform (such as a pulsed voltage), and the magnitude of the pulsed voltage is controlled by selecting a source voltage from at least two source voltages. 【0025】 Referring to Figure 4, what is shown is an exemplary power source topology utilizing the power supply components depicted in Figure 2. As shown, the power source topology includes at least two supply lines 204 coupled to supply node 102, each supply line 204 configured to selectively provide a corresponding source voltage to supply node 102. As depicted, each supply line 204 provides a corresponding source voltage (V1, V2, ..., V N Each supply line 204 also includes a corresponding source node 106 having a corresponding source voltage 106, and each supply line 204 also includes a corresponding supply line switch (which may include two or more series switches 108) coupled between the corresponding source node and the supply node, the corresponding supply line switch coupling the corresponding source voltage 106 to the supply node 102 when the corresponding supply line switch is closed. In addition, each supply line 204 includes a corresponding current bypass component 110 for bypassing leakage current either away from the corresponding source node 106 or away from the supply node 102 when the corresponding supply line switch is opened. Also shown is a controller 220 which may be used to control one or more aspects of the power supply components depicted in Figure 4. For example, the controller 220 may enable a selection of one of the supply lines 204 for applying power to the supply node 102. The controller may also be part of a feedback system and / or readback system that receives signals indicating one or more power-related parameters such as voltage, current, phase, and frequency, but is not limited to. The controller 220 can also be used in other power source variations that utilize the power source topology depicted in Figure 4. 【0026】 The use of multiple supply lines 204 and associated current bypass components 110, as depicted in Figure 4, reduces leakage current to enable various power source implementations. Referring to Figures 5 and 6, for example, is shown an embodiment of the leakage current problem in the context of a pulsed electric field (PEF) power source. As shown in Figures 5 and 6, the PEF includes a high-voltage source, a medium-voltage source, and a low-voltage source. As shown, for energy storage, capacitors may be used for each of the high-voltage, medium-voltage, and low-voltage sources. During operation, it is desirable to have one of the voltage sources supply power to the bridge circuit while the other two sources are discoupled from the bridge circuit. More specifically, it would be desirable to operate each source in an isolated manner from the other sources so that the voltage and corresponding leakage current produced by one voltage source do not adversely affect the other sources. However, the leakage current in the implementations depicted in Figures 5 and 6 presents a problem. 【0027】 Referring to Figure 5, for example, when the high voltage of a high-voltage source is coupled to the bridge circuit, undesirable leakage current flows through a semiconductor switch (e.g., a field-effect transistor (FET)) to the medium-voltage and low-voltage capacitors. These leakage currents will have detrimental effects due to the presence of high output voltages and, in some modes of operation, a very high rate of change (dv / dt) of the applied voltage, which exacerbates the leakage current. The immediate effect of the leakage current may be pulse inaccuracy (e.g., leakage current from the high voltage will affect the voltage levels of the medium-voltage and low-voltage), and there may be potential damage to internal circuitry, such as the low-voltage supply line output circuit. In the mode of operation depicted in Figure 6, the low-voltage switch is closed and a low voltage is applied to the bridge circuit, but the leakage current from the high-voltage source flows, detrimentally, to the bridge circuit and the medium-voltage source. 【0028】 Referring to Figure 7, shown is a pulsed electric field (PEF) power source incorporating, but not limited to, an embodiment of an approach to implementing and utilizing the current bypass approach disclosed herein. As shown in this embodiment, there are three supply lines, namely, a high-voltage supply line 704A, a medium-voltage supply line 704B, and a low-voltage supply line 704C. As depicted, each supply line includes a source node (706A, 706B, 706C) coupled to an energy storage device (e.g., a capacitor) having a source voltage, and a supply line switch (708A, 708B, 708C) coupled between the source node (706A, 706B, 706C) and the supply node 102, and the supply line switch includes at least two semiconductor switches arranged in series. In addition, each supply line (704A, 704B, 704C) also includes a current bypass component (710A, 710B, 710C). For example, a high-voltage supply line includes a corresponding source node 706A having a corresponding source voltage (which may be a relatively high voltage applied by a high-voltage energy storage component such as a capacitor, for example, but is not limited to a capacitor), and a high-voltage supply line 704A also includes a corresponding supply line switch 708A coupled between the corresponding source node 706A and the supply node 102, the corresponding supply line switch 708A coupling the corresponding source voltage (at source node 706A) to the supply node 102 when the corresponding supply line switch 708A is closed. In addition, a high-voltage supply line 704A includes a corresponding current bypass component 710A for bypassing leakage current either away from the corresponding source node 706A or away from the supply node 102 when the corresponding supply line switch 708A is opened. 【0029】 As shown, each current bypass component (710A, 710B, 710C) is configured to receive control signals (e.g., from controller 220 or other control network), and thereby the current bypass components control both the supply line switches (708A, 708B, 708C) and the corresponding bypass switches (712A, 712B, 712C). The current bypass switches (712A, 712B, 712C) may be implemented by, for example, insulated-gate bipolar transistors. As shown, the timing and driver network (714A, 714B, 714C) may be used to send bypass switch signals to close the current bypass switches (712A, 712B, 712C) when a series switch signal is sent to open the series switches (708A, 708B, 708C). Conversely, the timing and driver networks (714A, 714B, 714C) transmit bypass switch signals to open the current bypass switches (712A, 712B, 712C) when the series switch signals close the series switches (708A, 708B, 708C). As will be further discussed herein, the timing and driver networks (714A, 714B, 714C) control the timing of the series switch signals and bypass switch signals to prevent undesirable current paths. As shown, the series switch signals for opening / closing the series switches (708A, 708B, 708C) can be transmitted via floating drivers (716A, 716B, 716C), which propagate the series switch signals to open / close the series switches while galvanically isolating the timing and driver network (714A, 714B, 714C) from the series switches (708A, 708B, 708C). 【0030】 Referring to Figure 8, what is shown is a simplified representation of the pulsed electric field (PEF) power source of Figure 7 in a mode of operation in which the supply line switch (equipped with a set of series switches) of the low-voltage supply line 704C is closed. As shown, the leakage current of the high-voltage supply line 704A and the leakage current of the medium-voltage power source are diverted away from the supply node 102. In addition, leakage current that would normally originate from the high-voltage supply line 704A and flow through the medium-voltage supply line 704B (to the medium-voltage energy storage device) is diverted before it reaches the supply node 102. 【0031】 Next, referring to Figure 9, is shown an embodiment of a timing and driver network 914 that can be used to activate a current bypass path in a current bypass component when a series switch (one or more) is opened. Referring to Figure 9, Figure 10 is also referred to, which is a timing diagram depicting the timing of the series switch signal (series switch En / Dis), the bypass switch signal (Ileak_path_En / Dis) signal, and the control circuit signal (e.g., from a controller 220 or other control circuit network). As shown, in response to the control circuit providing a signal to open the series switch, there is a delay of T1_delay that causes the current bypass switch (transistor Q_hv) to close and provides a leakage current path (Ileak_path) before the bypass switch signal (Ileak_path_En / Dis) is sent to the current bypass switch (transistor Q_hv). 【0032】 In addition, Figure 10 depicts a delay (T2_delay) representing the delay between the opening of the current bypass switch and the closing of the series switch. As shown in Figure 9, the timing components (indicated by arrows) provide the induced resistive-capacitance (LRC) timing aspect of the timing and driver network 914. Those skilled in the art will readily be able to size each of the timing components to achieve desired values ​​for T1_delay and T2_delay in light of this disclosure. Also shown within the timing and driver network 914 is a driver that provides a signal of a magnitude capable of opening and closing the current bypass switch 912, as will readily be understood by those skilled in the art. It should be recognized that the depicted timing and driver network 914 and the current bypass component designs disclosed herein are merely examples, and that alternative designs may be used to open / close the series switch and close / open the current bypass switch. 【0033】 Referring to Figure 11, an embodiment is shown with pulsed patterns with low, medium, and high voltage outputs, which helps to activate the current bypass aspect disclosed herein. As shown, a PEF power source can produce short, intense bursts of electric field pulses used to apply a high-voltage electric field to various substances or materials over short periods. PEF generators find applications in many fields, including, but not limited to, the food industry, water and wastewater treatment, biotechnology, and medicine. 【0034】 In the medical field, PEF generators are particularly useful in cancer therapy. IRE electroporation, when applied to tumors in combination with previously impermeable anticancer drugs, can enable the drugs to reach the cell membrane and induce cell and tumor death. IRE electroporation can be induced when an electric field higher than approximately 1 kV / cm is applied to cells. In this case, the applied electric field is strong enough to irreparably damage the cell membrane, thus inducing cell death without the application of any drugs. As a result, IRE electroporation can be used in medical treatments requiring ablation of human tissue. Common examples include its use in pulsed field ablation (PFA) therapy for arrhythmias, or the use of PEF in treating skin lesions. 【0035】 The use of a PEF generator to induce electroporation of cancer cells in combination with the application of anticancer drugs to cancer cells is sometimes referred to as electrochemotherapy (ECT). ECT is useful for treating skin tumors that are not suitable for treatment by other methods such as excision. 【0036】 The methods described in connection with the embodiments disclosed herein may be embodied in hardware directly, in processor-executable code encoded in a non-transient tangible processor-readable storage medium, or in a combination of the two. Referring to Figure 12, for example, is shown a block diagram 4200 depicting physical components that may be used to implement the controller 220 and / or control circuits described herein. 【0037】 As shown, bus 4222 is coupled to non-volatile memory 4220, random access memory ("RAM") 4224, processing unit 4226 containing N processing components, field-programmable gate array (FPGA) 4227, and transceiver component 4228 containing N transceivers. None of these components are required, and any combination thereof may be included in the system disclosed herein. For example, if FPGA 4227 is implemented, processing unit 4226 may not be used, and vice versa. The components depicted in Figure 12 represent physical components, but Figure 12 is not intended to be a detailed hardware diagram, and therefore many of the components depicted in Figure 12 may be implemented by common constructs or distributed among additional physical components. Furthermore, it is assumed that other existing and undeveloped physical components and architectures may be used to implement the functional components described with reference to Figure 12. 【0038】 Generally, the non-volatile memory 4220 is a non-transient memory that functions to store (e.g., persistently store) data and processor executable code (including executable code associated with bringing about the methods described herein). In some embodiments, the non-volatile memory 4220 includes boot loader code, operating system code, file system code, and non-transient processor executable code to facilitate the execution of methods for coordinating the operation of the power source 300, as described herein. 【0039】 In many implementations, non-volatile memory 4220 is implemented using flash memory (e.g., NAND or one-NAND memory), but other memory types are also expected to be available. While it is possible to execute code from non-volatile memory 4220, executable code in non-volatile memory is typically loaded into RAM 4224 and executed by one or more of the N processing components in processing section 4226. 【0040】 The N processing components associated with RAM 4224 generally operate to execute instructions stored in non-volatile memory 4220 and to enable the methods for operating the power supply components and power sources disclosed herein. For example, non-transient processor executable code for bringing about the methods described herein may be persistently stored in non-volatile memory 4220 and executed by the N processing components associated with RAM 4224. As those skilled in the art will understand, the processing portion 4226 may include a video processor, a digital signal processor (DSP), a microcontroller, a graphics processing unit (GPU), or other hardware processing components, or a combination of hardware and software processing components (e.g., an FPGA or an FPGA including a digital logic processing portion). 【0041】 Generally, the input component 4230 operates to receive one or more analog and / or digital signals (e.g., current and / or voltage signals), and the output component 4232 generally operates to provide one or more analog or digital signals. For example, the output component 4232 and non-transient processor executable code may be used to enable a power source operator to obtain desired pulse parameters (e.g., by controlling a bridge network). In another specific embodiment, the output 4232 may provide control signals to be sent to a current bypass component. It is also conceivable that a display may be incorporated with the components depicted in Figure 12 to provide information about the power applied during operation. 【0042】 The transceiver component 4228 includes N transceiver chains that can be used to communicate with external devices via a wireless or wired network. Each of the N transceiver chains may represent a transceiver associated with a specific communication scheme (e.g., WiFi, Ethernet®, Profibus, etc.). 【0043】 Some parts are presented in terms of algorithms or symbolic representations of operations on data bits or binary digital signals stored in computing system memory, such as computer memory. These algorithmic descriptions or representations are examples of techniques used by those skilled in the field of data processing to communicate the substance of their work to others skilled in the field. An algorithm is a self-consistent sequence of actions or similar processes that lead to a desired result. In this context, the actions or processes involve the physical manipulation of physical quantities. Typically, but not always, such quantities may take the form of electrical or magnetic signals that can be stored, transferred, combined, compared, or otherwise manipulated. This proves that, at times, it is convenient to refer to such signals as bits, data, values, elements, symbols, characters, terms, digits, numbers, or equivalents, primarily for reasons of general use. However, it should be understood that all of these and similar terms are merely convenient labels, and are associated with appropriate physical quantities. Unless otherwise specifically stated, discussions throughout this specification using terms such as “processing,” “computing,” “calculating,” “determining,” and “identifying,” or equivalents, refer to actions or processes of computing devices, such as one or more computers or similar electronic computing devices, which manipulate or transform data that is represented as physical electronic or magnetic quantities in the memory, registers, or other information storage devices, transmission devices, or display devices of a computing platform. 【0044】 As will be understood by those skilled in the art, aspects of the present invention can be embodied as systems, methods, or computer program products. Thus, aspects of the present invention may take the form of entirely hardware embodiments, entirely software embodiments (including firmware, resident software, microcode, etc.), or embodiments combining software and hardware aspects, all of which may be referred to herein collectively as “circuit,” “module,” or “system.” Furthermore, aspects of the present invention may take the form of computer program products embodied in one or more computer-readable media having computer-readable program code embodied thereon. 【0045】 The word “exemplary” is used to mean “serving as an example, instance, or illustration.” Any embodiment described herein as “exemplary” should not be construed as being preferable or advantageous to other embodiments. 【0046】 The flowcharts and block diagrams in the drawings illustrate the architecture, functionality, and operation of possible implementations of the systems, methods, and computer program products according to various embodiments of this disclosure. In this regard, some blocks in the flowcharts and block diagrams may represent modules, segments, or portions of code, which contain one or more executable instructions for implementing a defined logical function. In some implementations, the functions described within a block may occur outside the order shown in the drawings. For example, two blocks shown consecutively may actually be executed substantially in parallel or in reverse order, depending on the associated functionality. It should also be understood that each block and combination of blocks in the flowcharts and block diagrams may be implemented by a special-purpose hardware-based system or a combination of special-purpose hardware and computer instructions that perform a defined function or action. 【0047】 The terms “First,” “Second,” “Third,” etc., may be used herein to describe various elements, components, areas, layers, and / or divisions, but it should be understood that these elements, components, areas, layers, and / or divisions are not limited by these terms. These terms are used merely to distinguish one element, component, area, layer, or division from another area, layer, or division. Therefore, the first element, component, area, layer, or division discussed below may be referred to as the second element, component, area, layer, or division without departing from the teachings of this disclosure. 【0048】 The terminology used herein is for the purpose of describing specific embodiments only and is not intended to limit this disclosure. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context explicitly indicates otherwise. As used herein, the terms “comprises” and / or “comprising” specify the presence of the described features, integers, steps, actions, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, actions, elements, components, and / or groups thereof. As used herein, the term “and / or” includes all combinations of one or more of the listed items relating together and may be abbreviated as “ / ”. 【0049】 As used herein, the enumeration of “at least one of A, B and C” or “at least one of A, B or C” is intended to mean “either A, B, C or any combination of A, B and C.” This description is provided to enable any person skilled in the art to make or use the disclosure. Various modifications to these embodiments will be readily apparent to a person skilled in the art, and the general principles defined herein may be applied to other embodiments without departing from the spirit or scope of the disclosure. Thus, the scope of the disclosure is not limited to the embodiments shown herein, but should be harmonized with the broadest range consistent with the principles and novel features disclosed herein.

Claims

[Claim 1] A power supply component, wherein the power supply component is A supply node to provide the supply voltage, supply line and Equipped with, The aforementioned supply line is A source node having a source voltage, A supply line switch coupled between the source node and the supply node, wherein when the supply line switch is closed, the supply line switch couples the source voltage to the supply node. When the supply line switch is opened, a current bypass component is used to divert the leakage current away from one or both of the source node and the supply node. A power supply component equipped with the following features. [Claim 2] The supply node comprises at least two supply lines connected thereto, each supply line configured to selectively provide a source voltage corresponding to the supply node, and each supply line is A corresponding source node having a corresponding source voltage, A corresponding supply line switch coupled between the corresponding source node and the supply node, wherein the corresponding supply line switch, when the corresponding supply line switch is closed, couples the corresponding source voltage to the supply node. When the corresponding supply line switch is opened, a corresponding current bypass component is used to bypass the leakage current either away from the corresponding source node or away from the supply node. The power supply component according to claim 1, comprising: [Claim 3] The power supply component according to claim 2, wherein the corresponding supply line comprises a set of two or more series switches. [Claim 4] The power supply component according to claim 3, wherein the corresponding current bypass component is coupled to a common node between two series switches. [Claim 5] The power supply component according to claim 4, wherein the corresponding current bypass component is coupled between the common node between the two series switches and the ground terminal. [Claim 6] The power supply component according to claim 1, wherein the supply line switch comprises a set of two or more series switches. [Claim 7] The power supply component according to claim 6, wherein at least one of the two or more series switches comprises a field-effect transistor. [Claim 8] It comprises at least one controller, and the at least one controller is Close one of the aforementioned switches to select the supply line and the corresponding source voltage, Disabling the current bypass component of the selected supply line, Enable one or more other current diversion components to divert current away from the source node of one or more unselected supply lines. A power supply component according to claim 1, configured to perform the following: [Claim 9] The power supply component according to claim 8, comprising a bridge circuit coupled to the supply node, wherein the bridge circuit is configured to apply a pulsed voltage, and the magnitude of the pulsed voltage is controlled by selecting a supply line and a corresponding source voltage. [Claim 10] A method, wherein the said method is The source voltage is coupled to the supply node via a switch in the supply line, and the source voltage is applied to the supply node. Opening the switch and disconnecting the source voltage from the supply node, While the switch is open, the leakage current is diverted away from one or both of the source node and the supply node. Methods that include... [Claim 11] The method according to claim 10, comprising selecting the source voltage from at least two source voltages by closing the switch on the supply line. [Claim 12] The selected source voltage is applied to the bridge circuit, The invention produces a pulsed voltage, the magnitude of which is controlled by selecting a source voltage from among the at least two source voltages. The method according to claim 11, including the method described in claim 11. [Claim 13] The method according to claim 10, wherein the coupling includes coupling the source voltage to the supply node via at least two series switches. [Claim 14] The method according to claim 13, wherein the bypass includes diverting the leakage current away from the node between the two switches to a bypass node. [Claim 15] The method according to claim 14, wherein the bypass includes diverting the leakage current away from the node between two of the switches to the ground terminal.

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