Suppression of rebalancing current in switched capacitor networks

Abstract

The invention relates to suppression of rebalancing current in switched capacitor networks. The power converter includes: a capacitor network including a path; and a controller for transitioning the capacitor network between a first state and a second state, where the first state and the second state occur substantially immediately after each other. The path comprises a flying capacitor and a rebalancing capacitor, the flying capacitor being configured to be charge unbalanced in the absence of the rebalancing capacitor relative to the capacitor network transitioning between the first state and the second state; the flying capacitor is configured to be charge balanced in the presence of the rebalancing capacitor relative to the capacitor network transitioning between the first state and the second state such that a capacitance of the rebalancing capacitor is substantially equal to a capacitance of the flying capacitor.

Description

[0001] This application is a divisional application of application number 202080068367.0 (International application number PCT / US2020 / 053336) with a filing date of September 29, 2020, and having the title “Suppression of Rebalancing Currents in a Switched-Capacitor Network,” and claims priority to U.S. Patent Application No. 16 / 588,060, filed September 30, 2019, entitled “Suppression of Rebalancing Currents in a Switched-Capacitor Network,” the contents of which are incorporated herein by reference in their entirety.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application claims priority to U.S. Patent Application No. 16 / 588,060, filed September 30, 2019, entitled “Suppression of Rebalancing Currents in a Switched-Capacitor Network,” the contents of which are incorporated herein by reference in their entirety. TECHNICAL FIELD

[0004] The present invention relates to power converters, and in particular to switched-capacitor networks within power converters. BACKGROUND

[0005] Modern electronic devices typically have different components that require power to operate. These components are demanding in their requirements. It is therefore important to provide a stable power source for each component.

[0006] A difficulty that arises is that the ultimate power source in many such devices is a battery. The voltage provided by a battery is not constant. As the battery discharges, this voltage begins to decrease. Changes in temperature can cause a recovery in this voltage. Changes in load likewise cause changes in the output voltage of the battery.

[0007] Even if a stable battery voltage can be ensured, there is a further difficulty. Different components have different power requirements. For example, a display on a smart phone typically requires a higher voltage than a processor. Since the battery can only provide one voltage, some way must be found to cater to the different requirements of the different components within the device.

[0008] To help maintain a stable voltage source to the various components, most such devices feature a power converter located between the battery and the various components. The function of the power converter is to take what the battery can provide and convert it into a form suitable for the various components that make up the device.

[0009] Known power converters use switched-capacitor networks in relation to performing their function. A difficulty with such networks is that, during their operation, charge moves from one capacitor to another. This movement causes heat to be generated, and heat generation results in energy loss. SUMMARY

[0010] In one aspect, the invention features an electrical power converter that includes a switching network and a controller that controls the switching network. The controller causes the switching network to form a switched capacitor circuit that includes a first path and a second path during an operation. The first path extends through a first capacitor network that includes a plurality of pump capacitors, and the second path extends through a second capacitor network that includes the same plurality of pump capacitors. The first path is connected to an anode and a cathode of a first pump capacitor of the plurality of pump capacitors. The second path is connected to the anode and the cathode of the first pump capacitor and to an anode and a cathode of a second pump capacitor of the plurality of pump capacitors. The anode of the first pump capacitor is connected to the anode of the second pump capacitor. The controller is configured such that when the anode of the first pump capacitor is connected to the anode of the second pump capacitor after the second capacitor network is formed, a voltage difference between the anodes is zero.

[0011] In some embodiments, the first path and the second path have different numbers of pump capacitors.

[0012] In other embodiments, the first path and the second path have the same capacitance.

[0013] In yet another embodiment, the controller is configured to cause the switching network to form a switched capacitor circuit that also includes a third path. The third path, formed in the first capacitor network, has the same capacitance as the first path.

[0014] There are also embodiments among these embodiments in which the controller is a controller that causes the switching network to form a switched capacitor circuit that also includes a third path, formed in the first capacitor network. The first path, the second path, and the third path all have the same capacitance.

[0015] Other embodiments include those in which the first path includes both a balancing capacitor and a first pump capacitor. Among these embodiments are embodiments in which, in some such embodiments, the second path includes only pump capacitors and no balancing capacitors, and in which the first path and the second path have the same capacitance; in some such embodiments, the balancing capacitor and the first pump capacitor have the same capacitance; in some such embodiments, the balancing capacitor stores charge on a first region and the first pump capacitor stores charge on a second region, and the second region exceeds the first region; in some such embodiments, the balancing capacitor stores charge on a first region and a second region separated by a first gap, and the first pump capacitor stores charge on a first region and a second region separated by a second gap, where the second gap exceeds the first gap.

[0016] In implementations in which the first path includes both a balancing capacitor and a first pump capacitor, there are also implementations in which: in some such implementations, the switching network includes a balancing switch that connects the balancing capacitor to the first pump capacitor; in some such implementations, the balancing capacitor increases the degree to which the power converter operates adiabatically relative to the degree to which the power converter operates adiabatically in the absence of the balancing capacitor; and in some such implementations, the balancing capacitor decreases the degree to which rebalancing current is present in the power converter relative to the degree to which rebalancing current would be present in the absence of the balancing capacitor.

[0017] In other implementations, the first capacitor network and the second capacitor network cooperate to convert the first voltage to the second voltage, where each of the first capacitor network and the second capacitor network includes a balancing capacitor. In these implementations, the first capacitor network and the second capacitor network would continue to convert the first voltage to the second voltage even if the balancing capacitor were omitted.

[0018] In yet another implementation, the capacitors of the plurality of pump capacitors are each charge-balanced.

[0019] There are also implementations in which the switched capacitor circuit is connected to one or more regulators.

[0020] In some implementations, the first capacitor network and the second capacitor network together define a cascaded multiplier.

[0021] In other implementations, the switching network includes a stack switch, a phase switch, and a balancing switch, where the balancing switch is smaller than the stack switch.

[0022] In yet another implementation, the plurality of pump capacitors includes a pump capacitor to be rebalanced, the switched capacitor circuit includes a balancing capacitor, and the switches of the switching network include a switch configured to disconnect the balancing capacitor from the pump capacitor to be balanced.

[0023] In another implementation, a power converter includes a switching network and a controller that controls the switching network. It is configured to cause the switching network to form a capacitor network. The capacitor network includes a first path and a second path, where each of the first path and the second path has at least one pump capacitor. As a result of the at least one pump capacitor, the first path and the second path have a corresponding first capacitance and a second capacitance. The first path also includes a rebalancing capacitor. As a result of the rebalancing capacitor and the at least one pump capacitor, the first path has a third capacitance. The magnitude of the difference between the first capacitance and the second capacitance is greater than the magnitude of the difference between the third capacitance and the second capacitance. Thus, the rebalancing capacitor has the effect of reducing charge redistribution between the two paths, and thus reducing losses from the resulting current that causes the charge redistribution.

[0024] As used herein, a controller that is "configured to cause" a condition is regarded as meaning the same as a controller that is "adapted to cause" the condition and a controller that "causes" the condition. In all cases, all the foregoing terms encompass a controller whether or not the controller is actually in operation. Thus, note that anyone who would interpret a claim to require that the apparatus actually be in operation for the claim to encompass the apparatus is in error in interpreting the claim because of a failure to interpret the claim in light of the specification. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 A power converter is shown with a regulator connected to a load;

[0026] Figure 2 A power converter is shown with a regulator connected to a voltage source;

[0027] Figure 3 A power converter is shown with a regulator connected to both a source and a load;

[0028] Figure 4 Details from a switched capacitor circuit are shown from Figure 1

[0029] Figure 5 and Figure 6 Two networks formed by different configurations of switches in the switched capacitor circuit shown by Figure 4

[0030] Figure 7 Details of a switched capacitor circuit similar to the one shown by Figure 4

[0031] Figure 8 and Figure 9 Details of a switched capacitor circuit similar to the one shown by Figure 7 ​​​Different configurations of the switches in the illustrated switched capacitor circuits form two networks. DETAILED DESCRIPTION

[0032] Figures 1 to 3 A first power converter 100, a second power converter 101, and a third power converter 102 are shown, each of which has a switched capacitor circuit 110. Each switched capacitor circuit 110 includes a capacitor bank 112 and a switch network 114 that uses the capacitor bank 112 to form different capacitor networks at different times. The process of dynamically forming these capacitor networks causes charge to be transferred between the capacitors. This charge transfer ultimately causes the switched capacitor circuit 110 to convert a first voltage presented at a first terminal 116 of the switched capacitor circuit to a second voltage available at a second terminal 118 of the switched capacitor circuit.

[0033] Figure 1 The type of power converter illustrated is described in detail in U.S. Patent No. 8,860,396, U.S. Patent No. 8,743,553, U.S. Patent No. 8,723,491, U.S. Patent No. 8,503,203, U.S. Patent No. 8,693,224, U.S. Patent No. 8,724,353, U.S. Patent No. 8,619,445, U.S. Patent No. 9,203,299, U.S. Patent No. 9,742,266, U.S. Patent No. 9,041,459, U.S. Pub. No. 2017 / 0085172, U.S. Patent No. 9,887,622, U.S. Patent No. 9,882,471, PCT Pub. No. WO2017161368, PCT Pub. No. WO2017 / 091696, PCT Pub. No. WO2017 / 143044, PCT Pub. No. WO2017 / 160821, PCT Pub. No. WO2017 / 156532, PCT Pub. No. WO2017 / 196826, and U.S. Pub. No. 2017 / 0244318, the contents of which are all incorporated herein by reference in their entirety.

[0034] Various different topologies can be used within the switched capacitor circuit 110. These topologies include Ladder, Dickson, Series-Parallel, Fibonacci, Cascade Multiplier, and Doubler topologies.

[0035] The voltage at the second terminal 118 of the switched capacitor circuit is equal to the product of the voltage at the first terminal 116 of the switched capacitor circuit and a voltage conversion factor. The voltage conversion factor is a number from a set formed by the union of a first set and a second set. The first set is the set of all positive integers. The second set is the set of reciprocals of the integers in the first set. When the voltage conversion factor belongs to the first set, the power converter 100 is referred to as a "step-up" power converter. When the voltage conversion factor belongs to the second set, the power converter 100 is referred to as a "step-down" power converter.

[0036] The controller 120 provides control signals to control the operation of the switching network 114. To perform these functions, the controller 120 relies on a programmable processor 122 and configuration data 124 and / or processor instructions that, when executed, cause the controller 120 to perform its tasks.

[0037] Other implementations include implementations in which the controller 120 relies on logic circuitry and implementations in which the controller 120 relies on analog circuitry to control the operation of the switching network 114.

[0038] Because the voltage conversion factor of the switched capacitor circuit 110 is chosen from a set of discrete values, there will be many voltages that the switched capacitor circuit 110 cannot provide. Therefore, the operating range of such a converter will have many large gaps. As a result, a power converter that relies solely on the switched capacitor circuit 110 will not be able to efficiently provide voltages that fall within these gaps. For this reason, it is useful to also provide a regulator.

[0039] Similar to the switched capacitor circuit 110, the regulator converts an input voltage to an output voltage. However, unlike the switched capacitor circuit 110, the regulator can in principle output any voltage within a continuous voltage operating range. This is in contrast to the switched capacitor circuit 110, which can only efficiently output voltages defined by the discrete set of voltage conversion factors. Therefore, the regulator is useful for being able to fill these gaps.

[0040] In the case of the first power converter 100, the load-side regulator 130 connects the second terminal 118 of the charge pump to the load 140. The first terminal 116 of the charge pump is connected to the power source 150. It is this power source 150 that provides the power to be converted by the power converter 100 in response to the control signals provided by the controller 120 on the control path 132.

[0041] To help the controller 120 decide what control signal to place on the control path 132, the controller 120 also receives sensor signals via the sensor path 134. These sensor signals provide information about how the switched capacitor circuit 110 is operating. Thus, the sensor path 134 allows the controller 120 to perform feedback control.

[0042] In the case of the second power converter 101, the supply-side regulator 160 connects the first terminal 116 of the charge pump to the power supply 150. The third power converter 102 includes both the load-side regulator 130 and the source-side regulator 160.

[0043] In some implementations, the regulator 130, the regulator 160 is a switched inductor circuit. Examples include a buck converter, a boost converter, a buck-boost converter (whether non-inverting or otherwise), a Cuk converter, a SEPIC converter, a resonant converter, a multi-level converter, a flyback converter, a forward converter, and a full-bridge converter. In such implementations, the controller 120 also provides control signals for controlling the switches of the regulator.

[0044] In other implementations, the regulator 130, the regulator 160 is a passive regulator. An example of a passive regulator is an inductor. Another example of a passive regulator is an LC tank. Such implementations obviate the need to control switches within the regulator 130, the regulator 160.

[0045] The regulator 130, the regulator 160— whether active or passive— typically includes an inductor. At the frequencies of interest, an inductor behaves like an ideal current source. For this reason, some of the figures use an ideal current source IOUT to represent the regulator 130, the regulator 160. Although the current source IOUT will be shown with an arrow in a particular direction to represent the current, this is not intended to imply the value of the current. Thus, the value of the current can be positive or negative. Thus, the ideal current source IOUT can be considered to be sourcing current or sinking current depending on the activity of the switched capacitor circuit 110 to which the regulator 130, the regulator 160 is connected.

[0046] Figure 4 Details of a particular switched capacitor circuit 110 are shown that receives an input voltage VIN at its first terminal 116 and provides an output voltage VOUT at its second terminal 118. The shown switched capacitor circuit 110 is a two-phase cascaded multiplier with a voltage conversion factor of 1 / 5. Thus, the output voltage VOUT is one fifth of the input voltage VIN. The ideal current source IOUT represents the load-side regulator 130.

[0047] The capacitor bank 112 includes first, second, third, and fourth outer pump capacitors CI A, CI B, C4A, and C4B, and first, second, third, and fourth inner pump capacitors C2A, C2B, C3A, and C3B. It is these pump capacitors that participate in voltage conversion.

[0048] The switch network 114 includes stack switches and phase switches.

[0049] The stack switches connect the anodes of the pump capacitors CI A, CI B, C4A, C4B, C2A, C2B, C3A, C4B to the anodes of adjacent pump capacitors or to one of the two terminals 116, 118 of the switched capacitor circuit 110. There are ten such stack switches in the illustrated circuit.

[0050] The phase switches connect the cathodes of the pump capacitors CI A, CI B, C4A, C4B, C2A, C2B, C3A, C4B to ground or to the output terminal 118 of the switched capacitor circuit 110. There are four such phase switches in the illustrated switch network 114.

[0051] The stack switches and the phase switches are divided into a first switch group 1 and a second switch group 2 that operate together as units. The controller 20 causes the switches in the first switch group 1 to open and close together, and causes the switches in the second switch group 2 to open and close together. In doing so, the controller 20 causes the switch network 114 to interconnect the capacitors from the capacitor bank 112 to first form a first capacitor network 136, and later to form a second capacitor network 138 using the same capacitors, as Figure 5 and Figure 6 illustrated.

[0052] Based on the configuration of the switch network 114, the switched capacitor circuit 110 transitions between a first state, a second state, and a third state to complete one operating cycle.

[0053] In the first state of the switched capacitor circuit, all of the switches in the first switch group 1 are closed, and all of the switches in the second switch group 2 are open. This forms the first capacitor network 136, as Figure 5 illustrated.

[0054] In the second state of the switched capacitor circuit, all of the switches in the first switch group 1 are open, and all of the switches in the second switch group 2 are closed. This forms the second capacitor network 138, as Figure 6 illustrated.

[0055] In the third state of the switched capacitor circuit, all switches in both the first switch set 1 and the second switch set 2 are open. Since all switches are open, the third state does not form any network.

[0056] The necessity of the third state arises because it is important to ensure that the switches in the first switch set 1 and the second switch set 2 do not simultaneously go into the closed state. Since these switches are implemented using transistors, it is necessary to take into account the fact that it is not possible to precisely control when a transistor will actually transition between the on state and the off state. By having a third state in which all switches are open, the likelihood of the switches from the first switch set 1 and the second switch set 2 simultaneously closing can be reduced.

[0057] In one operating cycle, the controller 120 opens and closes the switches in the switch network 114 to cause the switched capacitor circuit 110 to transition from the first state to the third state, from the third state to the second state, from the second state to the third state, and then from the third state back to the first state. Thus, each transition between the first state and the second state has an intervening third state. The time spent in this third state is the "dead time." To omit unnecessary complexity, it will be assumed in further discussion that the switched capacitor circuit 110 transitions directly between its first state and its second state.

[0058] Each of the first capacitor network 136 and the second capacitor network 138 formed during the first state and the second state has a plurality of charge transfer paths 152, 154, referred to herein simply as "paths." Each of these paths 152, 154 carries a current that ultimately contributes to the output current IOUT. The particular implementation shown includes low-capacitance paths 152 and high-capacitance paths 154. The first and fifth paths are high-capacitance paths 152. The remaining paths are low-capacitance paths 154. Thus, the currents through these paths 152, 154 are different.

[0059] During the first state, at least one of the capacitors shown will accumulate a first amount of charge. During the second state, that capacitor will lose a second amount of charge that it previously accumulated. If the first amount and the second amount are the same, then that capacitor is said to be "charge balanced." Otherwise, that capacitor is said to be "charge unbalanced."

[0060] If one compares Figure 5 and Figure 6 it is apparent that a capacitor that spends the first state on a high-capacitance path 154 can find itself on a low-capacitance path 152 for the second state.

[0061] For example, as Figure 5 and Figure 6As shown, the first external pump capacitor C1A passes through the first state on the high capacitance path 154 and the second state on the low capacitance path 152. As a result, the first external pump capacitor C1A will have different charging and discharging currents. As a result, the first external pump capacitor C1A will tend to become unbalanced.

[0062] Capacitors that become unbalanced during one state have the opportunity to correct for this in the next state. However, this comes at a cost in efficiency. To see why, it is useful to consider the interaction between the capacitors.

[0063] For example, suppose that at the end of the first state, the first capacitor becomes unbalanced. In the second state, the switches can connect the anode of the first capacitor to the anode of the second capacitor. If the two anodes are at different voltages, a rebalancing current will flow through the switch between the first capacitor and the second capacitor.

[0064] Although this process will correct the imbalance, it comes at a cost. Because the two anodes will effectively be shorted together, this rebalancing current can be quite large. This results in large ohmic losses. The ohmic losses caused by the rebalancing or redistribution of charge will be referred to herein as "redistribution losses."

[0065] This can be seen in Figure 6 , where the first external pump capacitor C1A finds its anode shorted to the anode of the first internal pump capacitor C2A. To the extent that there is a voltage difference between the two anodes involved, a large rebalancing current will flow between them.

[0066] One way to suppress the rebalancing current is to ensure that any two anodes that are to be connected together already have the same voltage when they are connected together. This ensures that no rebalancing current flows between the two anodes when they are connected.

[0067] For example, in the case of Figure 6 , if the anode of the first external pump capacitor is at the same voltage as the anode of the first internal pump capacitor, connecting the two anodes will not trigger the flow of a rebalancing current.

[0068] The amount of charge that enters or leaves any capacitor during a particular state is the integral of the current over the course of that state. Thus, to ensure that a capacitor gains and loses equal amounts of charge over the course of a cycle, it is important that the current integral for that capacitor be the same during the first time interval and the second time interval. Figure 7 A switched capacitor circuit 110 is shown that is similar to the switched capacitor circuit shown in Figure 4 , but that has been modified to implement only this condition, thereby reducing the risk of charge imbalance between the capacitors.

[0069] As Figure 7 shown, capacitor bank 112 includes two different types of capacitors. As in Figure 5 the case of capacitor bank 110, capacitor bank 112 includes first, second, third, and fourth outer pump capacitors C1A, C1B, C4A, C4B, and first, second, third, and fourth inner pump capacitors C2A, C2B, C3A, C3B. However, capacitor bank 112 also includes first and second balancing capacitors CR1, CR4.

[0070] The capacitances of these first and second balancing capacitors CR1, CR4 are chosen so that all of the paths 152, 154 in the first and second states will have the same capacitance. In the case where all of the pump capacitors C1A, C1B, C4A, C4B, C2A, C2B, C3A, C4B have the same capacitance, the first and second balancing capacitors CR1, CR4 will have the same capacitance as the pump capacitors C1A, C1B, C4A, C4B, C2A, C2B, C3A, C4B.

[0071] In addition to the ten stacked switches and four phase switches, switch network 114 includes first and second balancing switches 156, 158. First balancing switch 156 is part of first switch group 1. Second balancing switch 158 is part of second group 2.

[0072] The presence of balancing capacitors CR1, CR4 results in Figure 8 and Figure 9 the first and second capacitor networks 136, 138 shown in FIGS. 1 and 2.

[0073] As in Figure 5 and Figure 6 the case, the first and second capacitor networks 136, 138 are characterized by multiple paths. However, unlike those capacitor networks, which are characterized by a mix of high and low capacitance paths 154, 152, Figure 8 and Figure 9 the first and second capacitor networks 136, 138 shown in FIGS. 1 and 2 have only low capacitance paths 152. This reduces the likelihood of connecting two anodes that are not equal in voltage, and thus reduces the likelihood of rebalancing losses.

[0074] Balancing capacitors CR1, CR4 do not participate in voltage conversion. Thus, they do not need to store large amounts of charge. Their only role is to provide balancing capacitance. This frees them from the design constraints associated with pump capacitors C1A, C1B, C4A, C4B, C2A, C2B, C3A, C3B.

[0075] For a given inter-plate dielectric constant, the capacitance of a parallel-plate capacitor depends on the area of the plates and the separation between them. Thus, a large capacitance can be obtained by having large plates that are far apart from each other or small plates that are close together.

[0076] If the plates are large, they will consume a large amount of area on the integrated circuit. Since the cost of manufacturing a circuit depends on its total area, having large plates results in a more expensive circuit.

[0077] On the other hand, if the plates are made smaller and the inter-plate separation is also made smaller to achieve the same capacitance, the surface charge density will be greater for a given amount of charge stored on the plates. Thus, the electric field between the plates will become stronger. This high electric field, together with the smaller gap between the plates, creates a risk of dielectric breakdown and arcing across the dielectric.

[0078] Pump capacitors 112 are intended to store a large amount of charge and also to maintain a high dc bias voltage. Thus, they are typically very large so that the stored charge can be distributed over a large area. In fact, in some implementations, pump capacitors 112 are large enough that it is more practical to set them up as lumped circuit elements rather than as part of an integrated circuit.

[0079] However, this is not the case for balancing capacitors CR1, CR4. These balancing capacitors are only used to provide a capacitance value. In operation, they only store a symbolic amount of charge. Balancing capacitors CR1, CR4 also do not have to maintain a dc bias. Thus, balancing capacitors CR1, CR4 can be made very small. This means that they do not significantly increase the cost of manufacturing the circuit.

[0080] In operation, open-circuit stack switches typically have a high voltage across their terminals. Thus, even when a high voltage is urging current to flow, open-circuit stack switches must block the flow of current. This requires certain design compromises that result in physically large switches that consume a considerable amount of area on the integrated circuit.

[0081] Balancing switches 156, 158 avoid these design compromises. In operation, balancing switches 156, 158 will only have a low voltage ripple across their terminals. This means that balancing switches 156, 158 can be made physically smaller than stack switches 114.

[0082] In general, to facilitate efficient power conversion, it is useful for power converters 100, 101, 102 to have as much current as possible flow through the inductor. Since inductors tend to resist changes in current, this suppresses current transients that contribute to losses. In a 100% adiabatic power converter 100, 101, 102, all of the current will flow through the inductor.

[0083] The rebalancing current flows directly between the pump capacitors. It therefore does not flow through the inductor. To the extent that rebalancing current exists, it reduces the degree to which the power converter 100, 101, 102 is adiabatic. The use of balancing capacitors CR1, CR4 to suppress rebalancing current therefore facilitates adiabatic operation of the power converter 100, 101, 102 as a whole.

[0084] Having described the application and its preferred embodiments, what is now desired to be secured by Letters Patent is the subject matter as follows:

[0085] Further, the present disclosure provides the following configurations:

[0086] 1. An apparatus comprising a power converter, the power converter comprising a switching network and a controller that controls the switching network, wherein the controller is configured to cause the switching network to form a switched capacitor circuit, during operation, the switched capacitor circuit comprising a first path and a second path, wherein the first path extends through a first capacitor network comprising a plurality of pump capacitors, wherein the second path extends through a second capacitor network comprising the plurality of pump capacitors, wherein the first path is connected to an anode and a cathode of a first pump capacitor of the plurality of pump capacitors, wherein the second path is connected to the anode and the cathode of the first pump capacitor and to an anode and a cathode of a second pump capacitor of the plurality of pump capacitors, wherein the anode of the first pump capacitor is connected to the anode of the second pump capacitor, wherein the controller is configured such that when the anode of the first pump capacitor is connected to the anode of the second pump capacitor after forming the second capacitor network, a voltage difference between the anodes is zero.

[0087] 2. The apparatus of configuration 1, wherein the first path and the second path have different numbers of pump capacitors.

[0088] 3. The apparatus of configuration 1, wherein the first path and the second path have the same capacitance.

[0089] 4. The apparatus of configuration 1, wherein the controller is configured to cause the switching network to form a switched capacitor circuit that further comprises a third path, wherein the third path is a path formed in the first capacitor network, wherein the first path and the third path have the same capacitance.

[0090] 5. The apparatus of Configuration 1, wherein the controller is configured to cause the switch network to form a switched capacitor circuit that also includes a third path, wherein the third path is a path formed in the first capacitor network, wherein the first path, the second path, and the third path all have the same capacitance.

[0091] 6. The apparatus of Configuration 1, wherein the first path includes a balancing capacitor and the first pump capacitor.

[0092] 7. The apparatus of Configuration 6, wherein the second path includes only a pump capacitor and no balancing capacitor, and wherein the first path and the second path have the same capacitance.

[0093] 8. The apparatus of Configuration 6, wherein the balancing capacitor and the first pump capacitor have the same capacitance.

[0094] 9. The apparatus of Configuration 6, wherein the balancing capacitor stores charge on a first area, wherein the first pump capacitor stores charge on a second area, and wherein the second area exceeds the first area.

[0095] 10. The apparatus of Configuration 6, wherein the balancing capacitor stores charge on a first area and a second area separated by a first gap, wherein the first pump capacitor stores charge on a first area and a second area separated by a second gap, and wherein the second gap exceeds the first gap.

[0096] 11. The apparatus of Configuration 6, wherein the switch network includes a balancing switch, wherein the balancing switch connects the balancing capacitor to the first pump capacitor.

[0097] 12. The apparatus of Configuration 6, wherein the balancing capacitor increases a degree to which the power converter operates adiabatically relative to a degree to which the power converter operates adiabatically without the balancing capacitor.

[0098] 13. The apparatus of Configuration 6, wherein the balancing capacitor decreases a degree to which a rebalancing current exists in the power converter relative to a degree to which the rebalancing current would exist without the balancing capacitor.

[0099] 14. The apparatus of Configuration 1, wherein the first capacitor network and the second capacitor network cooperate to convert a first voltage to a second voltage, wherein each of the first capacitor network and the second capacitor network includes a balancing capacitor, wherein the first capacitor network and the second capacitor network would continue to convert the first voltage to the second voltage even if the balancing capacitor is omitted.

[0100] 15. The apparatus of Configuration 1, wherein the capacitors of the plurality of pump capacitors are each charge-balanced.

[0101] 16. The apparatus of Configuration 1, wherein the switched capacitor circuit is connected to a regulator.

[0102] 17. The apparatus of Configuration 1, wherein the switched capacitor circuit is connected to a first regulator and a second regulator.

[0103] 18. The apparatus of Configuration 1, wherein the first capacitor network and the second capacitor network together define a cascaded multiplier.

[0104] 19. The apparatus of Configuration 1, wherein the switch network includes a stack switch, a phase switch, and a balancing switch, wherein the balancing switch is smaller than the stack switch.

[0105] 20. The apparatus of Configuration 1, wherein the plurality of pump capacitors includes a pump capacitor to be rebalanced, wherein the switched capacitor circuit includes a balancing capacitor, wherein the switches of the switch network include a switch configured to disconnect the balancing capacitor from the pump capacitor to be balanced.

[0106] 21. An apparatus comprising a power converter, the power converter including a switch network and a controller to control the switch network, wherein the controller is configured to cause the switch network to form a capacitor network, wherein the capacitor network includes a first path and a second path, each of the first path and the second path having at least one pump capacitor, wherein as a result of the at least one pump capacitor, the first path and the second path have corresponding first and second capacitances, wherein the first path further includes a rebalancing capacitor, wherein as a result of the rebalancing capacitor and the at least one pump capacitor, the first path has a third capacitance, wherein a magnitude of a difference between the first capacitance and the second capacitance is greater than a magnitude of a difference between the third capacitance and the second capacitance.

Claims

1. A power converter, comprising: A capacitor network, the capacitor network including paths; as well as A controller for transitioning the capacitor network between a first state and a second state, wherein the first state and the second state occur substantially immediately after each other; The path includes a flying capacitor and a rebalancing capacitor, wherein the flying capacitor is configured to be charge unbalanced relative to the capacitor network transitioning between the first state and the second state in the absence of the rebalancing capacitor; The flying capacitor is configured to be charge-balanced relative to the capacitor network transitioning between the first and second states in the presence of the rebalancing capacitor, such that the capacitance of the rebalancing capacitor is substantially equal to the capacitance of the flying capacitor.

2. The power converter according to claim 1, wherein, The capacitance associated with the path is changed due to the rebalancing capacitor.

3. The power converter according to claim 1, wherein, The rebalancing capacitor is configured to improve the thermal insulation operation of the power converter.

4. The power converter according to claim 1, wherein, The rebalancing capacitor is configured to reduce the rebalancing current in the power converter.

5. The power converter according to claim 1, wherein, The controller is used to convert the first voltage into a second voltage.

6. The power converter according to claim 1, wherein, The controller is connected to the regulator.

7. The power converter according to claim 1, wherein, The controller is connected to the first regulator and the second regulator.

8. The power converter according to claim 1, wherein, The capacitor network includes cascaded multipliers.

9. The power converter according to claim 1, wherein, The capacitor network includes stacked switches, phase switches, and balance switches.

10. The power converter according to claim 1, further comprising: Switching networks, The controller enables the switching network to form a switched capacitor circuit that includes the capacitor network.

11. The power converter according to claim 10, wherein, The switching network includes a balance switch that connects the rebalancing capacitor to the flying capacitor.

12. The power converter according to claim 10, wherein, The controller converts a first voltage at the first terminal of the switched capacitor circuit into a second voltage at the second terminal of the switched capacitor circuit.

13. The power converter according to claim 12, wherein, The first terminal of the switched capacitor circuit is connected to a power source that supplies power in response to a control signal provided by the controller.

14. The power converter according to claim 1, wherein, The first state and the second state, which occur essentially immediately after each other, include the dead time between the first state and the second state.

15. A power converter, comprising: A capacitor network configured to transition between a first state and a second state; The capacitor network includes a rebalancing capacitor configured to reduce redistribution losses associated with the transition of the capacitor network between the first and second states. In the first state, the first pump capacitor is connected to the rebalancing capacitor, and the capacitance of the first pump capacitor is substantially equal to the capacitance of the rebalancing capacitor. In the second state, the second pump capacitor is connected to the third pump capacitor.

16. The power converter according to claim 15, wherein, The first pump capacitor is associated with the redistribution loss.

17. The power converter according to claim 15, wherein, The second pump capacitor is associated with the redistribution loss.

18. The power converter according to claim 15, wherein, The third pump capacitor is associated with the redistribution loss.

19. The power converter according to claim 15, wherein, The rebalancing capacitor improves the thermal insulation operation of the power converter.

20. The power converter according to claim 15, wherein, The rebalancing capacitor reduces the rebalancing current in the power converter.

21. The power converter according to claim 15, wherein, The capacitor network is used to convert the first voltage into a second voltage.

22. The power converter according to claim 15, wherein, The capacitor network is connected to the regulator.

23. The power converter according to claim 15, wherein, The capacitor network is connected to the first regulator and the second regulator.

24. The power converter according to claim 15, wherein, The capacitor network includes cascaded multipliers.

25. The power converter according to claim 15, wherein, The capacitor network includes stacked switches, phase switches, and balance switches.

26. The power converter according to claim 15, further comprising: Switching networks; as well as Controller The controller enables the switching network to form a switched capacitor circuit that includes the capacitor network.

27. The power converter according to claim 26, wherein, The switching network includes a balance switch that connects the rebalancing capacitor to the first pump capacitor.

28. The power converter according to claim 26, wherein, The controller converts a first voltage at the first terminal of the switched capacitor circuit into a second voltage at the second terminal of the switched capacitor circuit.

29. The power converter according to claim 28, wherein, The first terminal of the switched capacitor circuit is connected to a power source that supplies power in response to a control signal provided by the controller.

30. A power converter, comprising: Capacitor networks; as well as Controller, the controller controls the capacitor network, in: The capacitor network includes a first path and a second path, wherein the first path includes a first flying capacitor and a second flying capacitor connected in series, and the second path includes a third flying capacitor and a rebalancing capacitor connected in series, the rebalancing capacitor being selectively coupled to the third flying capacitor via a plurality of switches.

31. The converter according to claim 30, wherein, The first flying capacitor, the second flying capacitor, and the third flying capacitor each include a DC voltage component and an AC voltage component.

32. The converter according to claim 30, wherein, The rebalancing capacitor includes an AC voltage component.

33. The power converter according to claim 30, further comprising: Switching networks, The controller enables the switching network to form a switched capacitor circuit that includes the capacitor network.

34. The power converter according to claim 33, wherein, The switching network includes a balance switch that connects the rebalancing capacitor to the third flying capacitor.

35. The power converter according to claim 33, wherein, The controller converts a first voltage at the first terminal of the switched capacitor circuit into a second voltage at the second terminal of the switched capacitor circuit.

36. The power converter according to claim 35, wherein, The first terminal of the switched capacitor circuit is connected to a power source that supplies power in response to a control signal provided by the controller.

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