Battery charging and system power supply circuit combining capacitive and inductive charging

Abstract

A power converter having an input terminal, a capacitor, a first output terminal, a second output terminal, an output switch between the first output terminal and the second output terminal, and an inductor, wherein a first terminal of the inductor is connected to the first output terminal, the power converter further comprising: - an input switch connected between the input terminal and a first terminal of the capacitor; - a first capacitive charging switch connected between the first terminal of the capacitor and the second output terminal; - a second capacitive charging switch connected between the second output terminal and a second terminal of the capacitor; - a ground switch connected between the second terminal of the capacitor and a reference potential; - a first switch for inductive charging connected between the first terminal of the capacitor and a second terminal of the inductor; and - a second switch for inductive charging, which is connected between the second terminal of the inductor and the second terminal of the capacitor.

Description

Technical area

[0001] This document relates to power converters for capacitive and inductive battery charging. In particular, this document relates to power converters that can both charge a battery and supply energy to an electronic device, e.g., at a stable voltage. background

[0002] Charging a battery can involve different battery charging stages. Fig. 1 shows a graphical representation showing an exemplary charging current I CHG and an example charging voltage V BAT illustrated over time. In Fig. 1, the displayed charging states include: a pre-charging charging stage 1, a constant current (CC) charging stage 2, a step-down charging stage 3 specific to direct high-current charging, a constant voltage (CV) charging stage 4, an end-of-charge (EOC) charging stage 5, and a post-charging charging stage 6. It should be noted that, depending on the implementation, some of the displayed charging stages may be optional.

[0003] The present disclosure distinguishes between two types of charging devices that can be applied during the various battery charging stages: a direct capacitive charging device and a multi-stage inductive charging device. Fig. 2 and Fig. 3 illustrates an exemplary power converter 20 that includes both a direct capacitive charging device 21 and a multi-stage inductive charging device 22. As shown in Fig. 3, the direct capacitive charging device 21 comprises a capacitor CFLY1 and four switching elements SW1, SW2, SW3, and SW4. Optionally, the direct capacitive charging device 21 may comprise a second direct capacitive charging device 211 connected in parallel and comprising a capacitor CFLY2 and four switching elements SW5, SW6, SW7, and SW8. The multi-stage inductive charging device 22 comprises an inductor 221, a capacitor CFLY3, and four switching elements SW9, SW10, SW11, and SW12, and an output switch 222 arranged between a first output terminal 223 and a second output terminal 225 of the power converter 20. A system 224 (e.g., a smartphone) may be supplied with electrical power at the first output terminal 223, while a battery 226 is connected to the second output terminal 225. The battery 226 may, for example, be constructed according to the principles of the present invention. Fig. 1 shown charging states.

[0004] On the one hand, the direct capacitive charging device 21 taken alone (i.e., without the multi-stage inductive charging device 22) would have several disadvantages. For example, the direct capacitive charging device 21 taken alone would neither be able to pre-charge a depleted battery, nor would it supply the battery with a constant voltage, e.g., during the CV charging stage 4 after Fig. 1. Furthermore, the direct capacitive charger 21 would not be able to precisely stop charging the battery when the charging current is less than a certain limit. Furthermore, the direct capacitive charger 21 alone would not be able to charge with any voltage at the input (e.g., 5 V). In particular, it would require a voltage source capable of fine-tuning the input voltage to approximately twice the battery voltage. Furthermore, the direct capacitive charger 21 could not boost the power from the battery back to the input for power output at a fixed voltage (e.g., 5 V).

[0005] On the other hand, the multi-stage inductive charging device 22 alone (i.e., without the direct capacitive charging device 21) cannot achieve the same high efficiency as the capacitive charging device for similar sizes of power field-effect transistors (power FETs) and similar engineering parameters. In addition, the multi-stage inductive charging device 22 cannot eliminate the power losses of the output switch 222 and the inductor 221, which particularly affects the efficiency during high-current charging (i.e., during CC stage 2). Consequently, the Fig. 2 and Fig. 3, power converter 20 illustrated the advantages of both charging device types during the Fig. 1. To be more precise, the charging process of a battery can be controlled by controlling the switching elements of the direct capacitive charging device 21 and the multi-stage inductive charging device 22 during the various charging states shown in Fig. 1 shown charging levels can be optimized.

[0006] This paper addresses the above-mentioned technical problems. In particular, this paper addresses the technical problem of providing novel power converters suitable for both battery charging and system supply, and which can combine the advantages of both capacitive and inductive charging.

[0007] DE 102016225795 A1 relates to a DCDC power converter that has higher power efficiency and provides a higher maximum output current.

[0008] DE 102016104294 B4 relates to a method for converting electrical power and a power converter circuit, in particular a switched power converter circuit with several converter stages.

[0009] US 2018 / 0 115 157 A1 concerns systems, methods, apparatus, devices, articles of manufacture and instructions for energy management.

[0010] US 2018 / 0 354 372 A1 relates to a DC / DC converter with a flying capacitor configured to provide an increased voltage to an electric machine during a drive mode of an electric vehicle.

[0011] US 2014 / 0 266 135 A1 relates to boost converters and in particular to multi-stage boost converters and soft-start modules for multi-stage boost converters.

[0012] US 2017 / 0 300 079 A1 relates to devices, systems and methods for providing a reconfigurable Dickson-star connected capacitor voltage regulator and / or for providing a hybrid, e.g., two-stage voltage regulator. Summary

[0013] According to one aspect, a power converter is described. The power converter may include an input terminal, a capacitor, a first output terminal, a second output terminal, an output switch between the first output terminal and the second output terminal, and an inductor, wherein a first terminal of the inductor is connected to the first output terminal.The power converter may further comprise an input switch connected between the input terminal and a first terminal of the capacitor, a first capacitive charging switch connected between the first terminal of the capacitor and the second output terminal, a second capacitive charging switch connected between the second output terminal and a second terminal of the capacitor, a ground switch connected between the second terminal of the capacitor and a reference potential, a first inductive charging switch connected between the first terminal of the capacitor and a second terminal of the inductor, and a second inductive charging switch connected between the second terminal of the inductor and the second terminal of the capacitor.

[0014] Throughout this document, the term "reference potential" is used in its broadest possible sense. In particular, "reference potential" is not limited to a reference point with a direct physical connection to earth, such as ground. Instead, the term "reference potential" can refer to any reference point to and from which electrical currents can flow or from which voltages can be measured.

[0015] Each of the switches may be implemented by any suitable device, such as a metal-oxide-semiconductor field-effect transistor (MOSFET), an insulated-gate bipolar transistor (IGBT), a MOS-gated thyristor, or other suitable power device. Each switch has a gate to which a respective drive voltage or control signal may be applied to turn the switch on (i.e., close the switch) or off (i.e., open the switch).

[0016] The described power converter enables combined capacitive and inductive charging with a reduced number of circuit elements compared to the prior art solutions. Compared to the power converter 2 described in Fig. 3 and discussed in the background section above, the number of switches is reduced by two and the number of capacitors is reduced by one. Specifically, the described power converter enables the combined capacitive and inductive charging of an energy storage device, such as a battery or supercapacitor, connected to the second output terminal depending on the state of charge of the external energy storage device. As described in the following description, the power converter may be configured to convert electrical power at the input terminal into electrical power for powering an external electronic device at the first output terminal and / or into electrical power for charging the external energy storage device at the second output terminal.Depending on the state of charge of the external energy storage device, the power converter may be configured to supply electrical power to the external electronic device simultaneously while charging the external energy storage device connected to the second output terminal.

[0017] For example, when in capacitive charging mode, the power converter may be configured to turn off the output switch, the first inductive charging switch, and the second inductive charging switch, and to control the remaining switches to charge an external storage device connected to the second output terminal with a constant charging current. As an advantage, charging can be performed with high current and high efficiency. Furthermore, the charging current does not pass through the inductor or the output switch, thus eliminating the corresponding inductive, capacitive, and / or resistive losses.

[0018] The power converter may be configured to switch between a first phase and a second phase. The power converter may be further configured to turn on the input switch and the second capacitive charging switch, and to turn off the first capacitive charging switch and the ground switch during the first phase to create an electrical path from the input terminal via the capacitor to the second output terminal. Consequently, the first phase may be a charging phase during which the capacitor is charged via the electrical path. Conversely, the power converter may be configured to turn on the ground switch and the first capacitive charging switch, and to turn off the input switch and the second capacitive charging switch during the second phase to create an electrical path from the reference potential via the capacitor to the second output terminal.This means that the second phase can be a discharge phase during which the capacitor is discharged via the electrical path.

[0019] In other words, in the capacitive charging mode, the first and second capacitive charging switches may be responsible for transferring electrical energy from the capacitor to the second output terminal of the power converter. This is why, throughout this document, the first and second capacitive charging switches are referred to as the "capacitive" charging switches. At the same time, within the capacitive charging mode, the first inductive charging switch and the second inductive charging switch may be permanently off.

[0020] The described power converter may also be configured to turn off the first capacitive charging switch and the second capacitive charging switch and to control the remaining switches to regulate an output voltage at the first output terminal and / or the second output terminal when in the inductive charging mode. The power converter may be configured to switch between a first time interval, a second time interval, and a third time interval. The power converter may be configured to turn on the ground switch and the first inductive charging switch and turn off the input switch and the second inductive charging switch during the first time interval to create an electrical path from the reference potential via the capacitor and via the inductor to the first output terminal.In this disclosure, the terms "phase" and "time interval" are used synonymously. Then, during the second time interval, the power converter may be configured to turn on the input switch and the second inductive charging switch, and turn off the ground switch and the first inductive charging switch, to create an electrical path from the input terminal, via the capacitor, and via the inductor to the first output terminal. Finally, during the third time interval, the power converter may be configured to turn off the ground switch and the second inductive charging switch, and turn on the input switch and the first inductive charging switch, to create an electrical path from the input terminal, via the inductor, to the first output terminal.As a result, the power converter can be in a first switching state in which, during the first time interval, the capacitor is discharged and the inductor is demagnetized. During the second time interval, the power converter can be in a second switching state in which the capacitor is charged and the inductor is demagnetized. Finally, during the third time interval, the power converter can be in a third switching state in which the inductor is magnetized. By switching between these three switching states, the power converter can supply electrical power with a regulated output voltage to the first output terminal. The output switch can, for example, be turned off so that the electrical power is provided exclusively to the first output terminal.

[0021] In other words, in the inductive charging mode, the operation of the first and second inductive charging switches may be to transfer electrical energy through the inductor to the first output terminal of the power converter. This is why, throughout this document, the first and second inductive charging switches are referred to as the "inductive" charging switches. At the same time, within the inductive charging mode, the first capacitive charging switch and the second capacitive charging switch may be permanently off.

[0022] Alternatively or additionally, electrical power may also be provided to the second output terminal. In particular, the power converter may be configured to turn on the output switch and control the remaining switches so that an external storage device connected to the second output terminal is charged with a constant charging voltage. Alternatively, the inductor for charging this external storage device connected to the second output terminal may be demagnetized during the third time interval by turning on the ground switch and the second inductive charging switch and turning off the input switch and the first inductive charging switch to create an electrical path from the reference potential via the inductor to the second output terminal.In other words, the power converter may be configured to turn on the ground switch and the second inductive charging switch and turn off the input switch and the first inductive charging switch during a third time interval to create an electrical path from the reference potential via the inductor to the second output terminal. As a result of this alternative configuration, the capacitor is discharged within the third time interval, the inductor is magnetized during the first time interval, the capacitor is charged and the inductor is magnetized during the second time interval, and the inductor is demagnetized during the third time interval.By switching between these three switching states, the power converter can not only supply electrical power with a regulated output voltage to the first output terminal to power the external electronic device, but it can also charge an external energy storage device connected to the second output terminal with a regulated, almost constant voltage.

[0023] The power converter may include a second capacitor, a third capacitive charging switch, a fourth capacitive charging switch, a fifth capacitive charging switch, and a sixth capacitive charging switch. The third capacitive charging switch may be connected between the input terminal and a first terminal of the second capacitor. The fourth capacitive charging switch may be connected between the first terminal of the second capacitor and the second output terminal. The fifth capacitive charging switch may be connected between the second output terminal and a second terminal of the second capacitor. The sixth capacitive charging switch may be connected between the second terminal of the second capacitor and the reference potential.

[0024] The power converter may be further configured to turn on the third capacitive charging switch and the fifth capacitive charging switch, and turn off the fourth capacitive charging switch and the sixth capacitive charging switch, during the second phase to create an electrical path from the input terminal via the second inductor to the second output terminal. The power converter may be further configured to turn off the third capacitive charging switch and the fifth capacitive charging switch, and turn on the fourth capacitive charging switch and the sixth capacitive charging switch, during the first phase to create an electrical path from the reference potential via the second inductor to the second output terminal.

[0025] The third capacitive charging switch or the fourth capacitive charging switch may be implemented as a transistor and used as a voltage-controlled current source, wherein the power converter may be configured to turn off the transistor if a transistor current through the transistor falls below a threshold. The power converter may further comprise a comparator configured to compare the transistor current with the threshold.

[0026] The power converter may be configured to turn off the first and second capacitive charging switches in a boost mode and to switch between a magnetizing switching state and a demagnetizing switching state. In the magnetizing switching state, the second inductive charging switch and the ground switch are turned on. In the demagnetizing switching state, the input switch and the first inductive charging switch are turned on.Furthermore, in a boost-back mode, the power converter may be configured to turn off the first and second capacitive charging switches and to switch between a primary switching state in which the second inductive charging switch and the ground switch are turned on, a second switching state in which the first inductive charging switch and the ground switch are turned on, and a tertiary switching state in which the second inductive charging switch and the input switch are turned on.

[0027] The power converter may further comprise a first reverse current protection switch configured to connect a body of the first capacitive charging switch to a first reference potential, and a second reverse current protection switch configured to connect a body of the first inductive charging switch to a second reference potential. The first reference potential may be the same as the second reference potential or different from the second reference potential. In particular, the first and second reference potentials may be different from the reference potential to which the ground switch is connected. In addition, the power converter may further comprise a third reverse current protection switch configured to connect a body of the fourth capacitive charging switch to the reference potential.

[0028] According to a further aspect, a power converter is presented having an input terminal, a capacitor, a first output terminal, a second output terminal, an output switch between the first output terminal and the second output terminal, and an inductor, wherein a first terminal of the inductor is connected to the first output terminal. The power converter may include a first switch for inductive charging connected between the input terminal and a second terminal of the inductor. The power converter may include a second switch for inductive charging connected between the second terminal of the inductor and a reference potential. The power converter may include a first switch for capacitive charging connected between the first input terminal and a first terminal of the capacitor.The power converter may include a second switch for capacitive charging connected between the first terminal of the capacitor and the second output terminal. The power converter may include a third switch for capacitive charging connected between the second output terminal and a second terminal of the capacitor. The power converter may further include a fourth switch for capacitive charging connected between the second terminal of the capacitor and the reference potential.

[0029] According to yet another aspect, a method of operating a power converter is presented, the power converter comprising an input terminal, a capacitor, a first output terminal, a second output terminal, an output switch between the first output terminal and the second output terminal, and an inductor, a first terminal of the inductor being connected to the first output terminal. The method may comprise connecting an input switch between the input terminal and a first terminal of the capacitor. The method may comprise connecting a first switch for capacitive charging between the first terminal of the capacitor and the second output terminal. The method may comprise connecting a second switch for capacitive charging between the second output terminal and a second terminal of the capacitor.The method may include connecting a ground switch between the second terminal of the capacitor and a reference potential. The method may include connecting a first switch for inductive charging between the first terminal of the capacitor and a second terminal of the inductor. The method may include connecting a second switch for inductive charging between the second terminal of the inductor and the second terminal of the capacitor.

[0030] Furthermore, the method may comprise converting the electrical power at the input terminal into electrical power for supplying energy to an external electronic device at the first output terminal or into electrical power for charging an external energy storage device at the second output terminal.

[0031] The method may comprise, in a capacitive charging mode, turning off the output switch, the first inductive charging switch, and the second inductive charging switch, and controlling the remaining switches so that an external storage device connected to the second output terminal is charged with a constant charging current.

[0032] The method may further comprise, during a first phase, turning on the input switch and the second capacitive charging switch, and turning off the first capacitive charging switch and the ground switch to create an electrical path from the input terminal via the capacitor to the second output terminal. The method may further comprise, during a second phase, turning on the ground switch and the first capacitive charging switch, and turning off the input switch and the second capacitive charging switch to create an electrical path from the reference potential via the capacitor to the second output terminal.

[0033] The method may comprise, in an inductive charging mode, turning off the first capacitive charging switch and the second capacitive charging switch and controlling the remaining switches to regulate an output voltage at the first output terminal.

[0034] The method may further comprise, during a first time interval, turning on the ground switch and the first inductive charging switch, and turning off the input switch and the second inductive charging switch to create an electrical path from the reference potential, via the capacitor and via the inductor, to the first output terminal. The method may further comprise, during a second time interval, turning on the input switch and the second inductive charging switch, and turning off the ground switch and the first inductive charging switch to create an electrical path from the input terminal, via the capacitor and via the inductor, to the first output terminal.Finally, the method may further comprise, during a third time interval, turning off the ground switch and the second inductive charging switch and turning on the input switch and the first inductive charging switch to create an electrical path from the input terminal via the inductor to the first output terminal.

[0035] The method may include turning on the output switch and controlling the remaining switches so that an external storage device connected to the second output terminal is charged with a constant charging voltage.

[0036] The method may further comprise, during the third time interval, turning on the ground switch and the second inductive charging switch and turning off the input switch and the first inductive charging switch to create an electrical path from the reference potential via the inductor to the second output terminal.

[0037] The method may further comprise adding to the power converter a second capacitor, a third capacitive charging switch, a fourth capacitive charging switch, a fifth capacitive charging switch, and a sixth capacitive charging switch. The method may further comprise connecting the third capacitive charging switch between the input terminal and a first terminal of the second capacitor. The method may further comprise connecting the fourth capacitive charging switch between the first terminal of the second capacitor and the second output terminal. The method may further comprise connecting the fifth capacitive charging switch between the second output terminal and a second terminal of the second capacitor.The method may further comprise switching the sixth switch for capacitive charging between the second terminal of the second capacitor and the reference potential.

[0038] The method may further comprise, during the first phase, turning on the third capacitive charging switch and the fifth capacitive charging switch, and turning off the fourth capacitive charging switch and the sixth capacitive charging switch to create an electrical path from the input terminal via the second inductor to the second output terminal. Furthermore, during the second phase, the method may further comprise turning off the third capacitive charging switch and the fifth capacitive charging switch, and turning on the fourth capacitive charging switch and the sixth capacitive charging switch to create an electrical path from the reference potential via the second inductor to the second output terminal.

[0039] The method may further comprise implementing the third capacitive charging switch or the fourth capacitive charging switch as a transistor and using the transistor as a voltage-controlled current source. The method may further comprise turning off the transistor if a transistor current through the transistor falls below a threshold. The method may further comprise comparing the transistor current to a threshold using a comparator.

[0040] According to yet another aspect, a method is presented for operating a power converter having an input terminal, a capacitor, a first output terminal, a second output terminal, an output switch between the first output terminal and the second output terminal, and an inductor, wherein a first terminal of the inductor is connected to the first output terminal. The method may include connecting a first switch for inductive charging between the input terminal and a second terminal of the inductor. The method may include connecting a second switch for inductive charging between the second terminal of the inductor and a reference potential. The method may include connecting a first switch for capacitive charging, connected to the input terminal, and a first terminal of the capacitor.The method may include connecting a second switch for capacitive charging between the first terminal of the capacitor and the second output terminal. The method may include connecting a third switch for capacitive charging between the second output terminal and a second terminal of the capacitor. The method may include connecting a fourth switch for capacitive charging between the second terminal of the capacitor and the reference potential.

[0041] It should be noted that the methods and systems, including their preferred embodiments, as outlined in the present document can be used standalone or in combination with other methods and systems disclosed in this document. Additionally, the features outlined in the context of a system are also applicable to a corresponding method. Furthermore, all aspects of the methods and systems outlined in the present document can be combined in any desired manner. In particular, the features of the claims can be combined with each other in any desired manner.

[0042] In this document, the term "couple", "connect", "coupled" or "connected" refers to elements that are either directly connected, for example, by wires, or electrically connected in some other way. Brief description of the drawings

[0043] The invention will now be explained by way of example with reference to the accompanying drawings, in which Fig. 1 shows a graphical representation with different battery charge levels; Fig. 2 shows an exemplary power converter with a direct capacitive charging device and a multi-stage inductive charging device; Fig. 3 shows an exemplary power converter with a direct capacitive charging device and a multi-stage inductive charging device; Fig. 4 shows an exemplary power converter for combined capacitive and inductive charging; Fig. Figure 5 shows the currents flowing during capacitive charging; Fig. 6 shows further currents flowing during capacitive charging; Fig. 7 shows the current flows according to a first option for inductive EOC charging; Fig. Figure 8 shows the current flows according to the first option for inductive EOC charging; Fig. 9 shows the current flows according to the first option for inductive EOC charging; Fig. 10 shows the current flows according to a second option for inductive EOC charging; Fig. 11 shows the current flows during inductive charging of an external battery; Fig. 12 shows the current flows during inductive charging of an external battery; Fig. 13 shows the current flows during inductive charging of an external battery; Fig. 14 shows the current flows during capacitive charging of an external battery, while the inductive charger supplies a stable output voltage to an external system; Fig. 15 shows the current flows during capacitive charging of an external battery, while the inductive charger supplies a stable output voltage to an external system; Fig. Figure 16 shows the current flows during capacitive charging of an external battery, while the inductive charger supplies a stable output voltage to an external system; Fig. 17 shows the current flows during the re-boost according to a first circuit diagram; Fig. 18 shows the current flows during the re-boost according to the first circuit diagram; Fig. 19 shows the current flows during the re-boost according to a second circuit diagram; Fig. 20 shows the current flows during the re-boost according to the second circuit diagram; Fig. 21 shows the current flows during the re-boost according to the second circuit diagram; Fig. 22 shows a power converter with reverse current protection; and Fig. 23 shows another exemplary power converter with a direct capacitive charging device and an indirect inductive charging device. Detailed description

[0044] Fig. 4 shows an exemplary power converter 40 according to the teachings of the present disclosure. The exemplary power converter 40 includes an input terminal, a capacitor 43, a first output terminal, a second output terminal, an output switch 45 between the first output terminal and the second output terminal, and an inductor 44, with a first terminal of the inductor 44 connected to the first output terminal.The power converter 40 further includes an input switch SW1 connected between the input terminal and a first terminal of the capacitor 43, a first switch SW2 for capacitive charging connected between the first terminal of the capacitor 43 and the second output terminal, a second switch SW3 for capacitive charging connected between the second output terminal and a second terminal of the capacitor 43, a ground switch SW4 connected between the second terminal of the capacitor 43 and a reference potential, a first switch SW9 for inductive charging connected between the first terminal of the capacitor 43 and a second terminal of the inductor 44, and a second switch SW10 for inductive charging connected between the second terminal of the inductor 44 and the second terminal of the capacitor 43.The power converter 40 converts the electrical power at the input terminal into electrical power for supplying energy to the external electronic device 224 at the first output terminal and / or into electrical power for charging the external energy storage device 226 at the second output terminal.

[0045] Optionally, the exemplary power converter 40 may include an optional capacitive charging device 41 comprising a second capacitor 42, a third capacitive charging switch SW5, a fourth capacitive charging switch SW6, a fifth capacitive charging switch SW7, and a sixth capacitive charging switch SW8. The third capacitive charging switch SW5 is connected between the input terminal and a first terminal of the second capacitor 42. The fourth capacitive charging switch SW6 is connected between the first terminal of the second capacitor 42 and the second output terminal. The fifth capacitive charging switch SW8 is connected between the second output terminal and a second terminal of the second capacitor 42. The sixth capacitive charging switch SW8 is connected between the second terminal of the second capacitor 42 and the reference potential.

[0046] The Fig. 5 and Fig. 6 illustrate the electrical currents within the exemplary power converter 40 when operating in a capacitive charging mode. In the capacitive charging mode, the power converter turns off the output switch, the first inductive charging switch, and the second inductive charging switch, while controlling the remaining switches to charge the external storage device connected to the second output terminal with a constant charging current.

[0047] During a Fig. 6, to create an electrical path from the input terminal via the capacitor 43 to the second output terminal, the power converter 40 turns on the input switch SW1 and the second capacitive charging switch SW10, while turning off the first capacitive charging switch SW9 and the ground switch SW4. Consequently, the first phase may be a charging phase during which the capacitor 43 is charged via the electrical path. At the same time, to create an electrical path from the reference potential via the second inductor to the second output terminal, the power converter 40 turns off the third capacitive charging switch SW5 and the fifth capacitive charging switch SW7, while turning on the fourth capacitive charging switch SW6 and the sixth capacitive charging switch SW8. In other words, the capacitor 43 is charged while the second capacitor 42 is discharged.

[0048] During a Fig. 5, the power converter turns on the ground switch SW4 and the first capacitive charging switch SW2 to create an electrical path from the reference potential via the capacitor 42 to the second output terminal, while turning off the input switch SW1 and the second capacitive charging switch SW3. That is, the second phase may be a discharge phase during which the capacitor 42 is discharged via the electrical path. At the same time, the power converter 40 turns on the third capacitive charging switch SW5 and the fifth capacitive charging switch SW7 to create an electrical path from the input terminal via the second inductor 42 to the second output terminal, while turning off the fourth capacitive charging switch SW6 and the sixth capacitive charging switch SW8. In other words, in the second phase, the capacitor 43 is discharged while the second capacitor 42 is charged.

[0049] In the Fig. 7, Fig. 8 and Fig. 9 is a first option for optimizing EOC level 5 according to Fig. 1. The inductive charging device is used to supply the VSYS to the external system (as described later), while the output switch 45 (e.g., a FET) between the VSYS and the VBAT serves as a voltage-controlled current source. The IBAT current is set by the output switch 45 in such a way that the VBAT is maintained at a value equal to VBAT_EOC. While the battery at the second output terminal is still being charged, the IBAT current decreases. When the IBAT falls below a predetermined value IBAT_EOC, the output switch 45 (the IBAT current source) is turned off.

[0050] In Fig. 10 is a second option for optimizing EOC level 5 after Fig. 1. The left (optional) branch of the capacitive charger is used as a linear charger, while the inductive charger is used only to supply power to the VSYS, being separated from the VBAT, i.e., the output switch 45 between the VSYS and the VBAT is turned off. This method has the advantage that the two power converters (the linear charger on the left and the multi-stage converter on the right) are independent of each other. Consequently, the IBAT control is more stable and is less affected by load changes on the VSYS. The charging termination mechanism is similar to Option 1 (IBAT and IBAT_EOC comparator), with the difference that the IBAT current source is implemented within the direct charger branch instead of the BAT FET. In other words, in Fig. 10, the third switch SW5 for capacitive charging or the fourth switch SW6 for capacitive charging is implemented as a transistor, being used as a voltage-controlled current source, wherein the power converter 40 turns off the transistor if a transistor current through the transistor falls below a threshold. As in Fig. 10, the power converter 40 further includes a comparator configured to compare the transistor current with the threshold value.

[0051] The Fig. 11, Fig. 12 and Fig. 13 show the current flows during inductive charging of an external battery. As in Fig. 11, during a first time interval, the power converter switches on the ground switch SW4 and the first inductive charging switch SW9 to create an electrical path from the reference potential via the capacitor 43 and the inductor 44 to the first output terminal, while switching off the input switch SW1 and the second inductive charging switch SW10. Then, in Fig. 12 during a second time interval, the power converter switches on the input switch SW1 and the second inductive charging switch to create an electrical path from the input terminal via the capacitor and via the inductor to the first output terminal, while switching off the ground switch and the first inductive charging switch. Finally, in Fig. 13 During a third time interval, the power converter, in order to create an electrical path from the input terminal via the inductor to the first output terminal, switches off the ground switch and the second inductive charging switch, while switching on the input switch and the first inductive charging switch. By switching between the described switching states, the power converter supplies electrical power to the first output terminal at a regulated output voltage. As in Fig. 11, Fig. 12 and Fig. 13, the output switch is turned on, and the voltage-stabilized electrical power is also supplied to the battery at the second output terminal of the power converter 40.

[0052] The Fig. 14, Fig. 15 and Fig. 16 show the current flows during capacitive charging of an external battery while the inductive charging device supplies a stable output voltage to an external system. In this scenario, the output switch 45 is off. The inductive charging is carried out using a similar circuit pattern as described with respect to Fig. 11, Fig. 12 and Fig. 13, except that during the third time interval, an electrical path is established from the input terminal to the first output terminal. This system allows the VSYS to be supplied and the battery to be charged simultaneously. Here are some scenarios where this is useful: (a) pre-charge, where the optional left branch may be required to simultaneously and independently pre-charge and supply system power, (b) CV and charge termination, where the optional left branch is required to simultaneously and independently pre-charge and supply system power, and (c) after this is accomplished, when the battery is full, where the left side may not be required for this function.

[0053] If a power sink is present at the input terminal of the power converter 40 instead of a power source, and the battery is connected to the output of the charger, the battery power can be boosted back to provide power to the input. Two methods are presented in this disclosure: the 2-step boost and the 3-step boost. Fig. 17 and Fig. 18 show the current flows during the re-boost according to the first switching scheme (2-stage boost), whereas the Fig. 19, Fig. 20, Fig. 21 shows the current flows during the re-boost according to the second circuit diagram (3-step boost). The two-step boost has two phases: magnetizing the inductor 44 and then demagnetizing it by increasing the power to the input terminal VIN. During both phases, the flying capacitor 43 used by the multi-stage inductive charging device is connected between the input terminal VIN and the reference potential (ground), acting as an output capacitor for the (re-)boost converter. The three-step boost has three phases. This is specific to a 3-step boost using an inductor and a flying capacitor.

[0054] A battery charger circuit must also protect the battery from uncontrolled discharge in the event that a load is connected to the input terminal or VIN is shorted to ground. This feature is called reverse current protection (RCP). Typically, a battery charger uses an additional power FET (switch) connected in series with its input, also called an RCP FET. When this switch is off, there is no current from the output to the input. The RCP FET is on during charging and boosting, but it increases the overall power losses in the circuit.

[0055] Fig. Figure 22 shows a power converter with reverse current protection. In general, the circuit presented in this disclosure can achieve the RCP within the described power FETs. To demonstrate the RCP method, the circuit according to this disclosure is considered (without loss of generality) using N-type power FETs for its switches. Fig. Figure 22 also shows the body diodes of SW1, SW2, SW5, SW6, and SW9, as they provide the main paths for reverse current. While the power converter is switching, the bodies of SW2, SW6, and SW9 must be connected to the sources of their transistors to cancel the body bias effect, which would increase power losses. When the charger is off and the output switch SWBAT is on (to provide power from VBAT to VSYS), the charger circuit must prevent uncontrolled current flow from the battery to the input. If there is a load on VIN that reduces the VIN voltage below VBAT / VSYS (or even a short circuit at VIN to ground), the body diodes of SW1, SW2, SW5, SW6, and SW9 will begin conducting current from the battery to the input.The idea of the present disclosure is to ground the bodies of SW2, SW6, and SW9 when the charger is not in use for charging or boosting. This effectively prevents current flow from the battery to the input without additional power FETs in series with the charger.

[0056] Fig.23 shows another exemplary power converter 230 with a direct capacitive charging device and an indirect inductive charging device. The power converter 230 has an input terminal, a capacitor 233, a first output terminal, a second output terminal, an output switch 238 between the first output terminal and the second output terminal, and an inductor 239, with a first terminal of the inductor 239 connected to the first output terminal. The power converter 230 has a first switch 236 for inductive charging connected between the input terminal and a second terminal of the capacitor. The power converter has a second switch 237 for inductive charging connected between the second terminal of the inductor and a reference potential.The power converter includes a first capacitive charging switch 231 connected between the input terminal and a first terminal of the capacitor 233. The power converter includes a second capacitive charging switch 232 connected between the first terminal of the capacitor 233 and the second output terminal. The power converter includes a third capacitive charging switch 234 connected between the second output terminal and a second terminal of the capacitor. The power converter includes a fourth capacitive charging switch 235 connected between the second terminal of the capacitor and the reference potential. The power converter 230 can be particularly valuable during precharging and in an EOC phase.

[0057] It should be noted that the description and drawings merely illustrate the principles of the proposed methods and systems. Those skilled in the art may implement various arrangements that, although not explicitly described or shown herein, embody the principles of the invention and are included within its spirit and scope. Furthermore, all examples and embodiments outlined in the present document are expressly intended for explanatory purposes only to assist the reader in understanding the principles of the proposed methods and systems. Furthermore, all explanations providing the principles, aspects, and embodiments of the invention, as well as their specific examples, are intended to encompass their equivalents.

Claims

[1] A power converter having an input terminal, a capacitor, a first output terminal, a second output terminal, an output switch between the first output terminal and the second output terminal, and an inductor, a first terminal of the inductor being connected to the first output terminal, the power converter further comprising: - an input switch connected between the input terminal and a first terminal of the capacitor; - a first capacitive charging switch connected between the first terminal of the capacitor and the second output terminal; - a second capacitive charging switch connected between the second output terminal and a second terminal of the capacitor; - a ground switch connected between the second terminal of the capacitor and a reference potential; - a first switch for inductive charging connected between the first terminal of the capacitor and a second terminal of the inductor; and - a second switch for inductive charging, which is connected between the second terminal of the inductor and the second terminal of the capacitor. [2] The power converter according to claim 1, wherein the power converter is configured to convert electrical power at the input terminal into - electrical power for supplying an external electronic device at the first output terminal with energy or in - electrical power for charging an external energy storage device at the second output terminal. [3] A power converter according to any one of the preceding claims, wherein the power converter is configured, when in a capacitive charging mode, - switch off the output switch, the first inductive charging switch and the second inductive charging switch and - to control the remaining switches so that an external storage device connected to the second output terminal is charged with a constant charging current. [4] The power converter of any preceding claim, wherein the power converter is further configured to switch between a first phase and a second phase, wherein the power converter is configured to, during the first phase - switch on the input switch and the second switch for capacitive charging and - switching off the first switch for capacitive charging and the ground switch for creating an electrical path from the input terminal via the capacitor to the second output terminal; and wherein the power converter is configured, during the second phase - switch on the ground switch and the first switch for capacitive charging and - switching off the input switch and the second capacitive charging switch to create an electrical path from the reference potential via the capacitor to the second output terminal. [5] A power converter according to any one of the preceding claims, wherein the power converter is configured, when in an inductive charging mode, - switch off the first capacitive charging switch and the second capacitive charging switch and - to control the remaining switches for regulating an output voltage at the first output terminal or at the second output terminal. [6] The power converter of claim 5, wherein the power converter is configured to alternate between a first time interval, a second time interval, and a third time interval, wherein the power converter is configured to, during the first time interval - switch on the ground switch and the first switch for inductive charging and - switching off the input switch and the second inductive charging switch to create an electrical path from the reference potential via the capacitor and via the inductor to the first output terminal, wherein the power converter is configured to, during the second time interval - switch on the input switch and the second switch for inductive charging and - switching off the ground switch and the first inductive charging switch to create an electrical path from the input terminal via the capacitor and via the inductor to the first output terminal, and wherein the power converter is configured to, during the third time interval - switch off the ground switch and the second switch for inductive charging and - switching on the input switch and the first inductive charging switch to create an electrical path from the input terminal via the inductor to the first output terminal. [7] A power converter according to any one of the preceding claims, wherein the power converter is configured, when in an inductive charging mode, - switch on the output switch, - switch off the first capacitive charging switch and the second capacitive charging switch and - to control the remaining switches so that an external storage device connected to the second output terminal is charged with a constant charging voltage, or so that a constant charging voltage is provided at the first output terminal. [8] The power converter of claim 6, wherein the power converter is configured to, during a third time interval - switch on the ground switch and the second switch for inductive charging and - switching off the input switch and the first inductive charging switch to create an electrical path from the reference potential via the inductor to the second output terminal. [9] The power converter of claim 4, wherein the power converter further comprises a second capacitor, a third capacitive charging switch, a fourth capacitive charging switch, a fifth capacitive charging switch, and a sixth capacitive charging switch, wherein - the third switch for capacitive charging is connected between the input terminal and a first terminal of the second capacitor; - the fourth switch for capacitive charging is connected between the first terminal of the second capacitor and the second output terminal; - the fifth switch for capacitive charging is connected between the second output terminal and a second terminal of the second capacitor; and - the sixth switch for capacitive charging is connected between the second terminal of the second capacitor and the reference potential. [10] The power converter of claim 9, wherein the power converter is further configured to, during the second phase - switch on the third switch for capacitive charging and the fifth switch for capacitive charging and - to switch off the fourth capacitive charging switch and the sixth capacitive charging switch to create an electrical path from the input terminal via the second inductor to the second output terminal, and during the first phase - turn off the third capacitive charging switch and the fifth capacitive charging switch and - switching on the fourth capacitive charging switch and the sixth capacitive charging switch to create an electrical path from the reference potential via the second inductor to the second output terminal. [11] The power converter of claim 9, wherein the third capacitive charging switch or the fourth capacitive charging switch is implemented as a transistor, the power converter being configured to turn off the transistor if a transistor current through the transistor falls below a threshold. [12] The power converter of claim 11, wherein the power converter further comprises a comparator configured to compare the transistor current with the threshold value. [13] The power converter of any preceding claim, wherein the power converter is configured to turn off the first and second capacitive charging switches in a boost mode and to switch between - a magnetization switching state in which the second switch for inductive charging and the ground switch are switched on, and - a demagnetization switching state in which the input switch and the first inductive charging switch are switched on. [14] The power converter of any preceding claim, wherein the power converter is configured to turn off the first and second capacitive charging switches in a boost mode and to switch between - a primary switching state in which the second switch for inductive charging and the ground switch are switched on, - a second switching state in which the first switch for inductive charging and the ground switch are switched on, and - a tertiary switching state in which the second switch for inductive charging and the input switch are switched on. [15] Power converter according to one of the preceding claims, wherein the power converter further comprises - a first reverse current protection switch configured to connect a body of the first capacitive charging switch to a first reference potential, and - a second reverse current protection switch configured to connect a body of the first inductive charging switch to a second reference potential. [16] A power converter having a third input terminal, a capacitor, a first output terminal, a second output terminal, an output switch between the first output terminal and the second output terminal, and an inductor, a first terminal of the inductor being connected to the first output terminal, the power converter further comprising: - a first inductive charging switch connected between the input terminal and a second terminal of the inductor; - a second switch for inductive charging, which is connected between the second terminal of the inductor and a reference potential; - a first capacitive charging switch connected between the first input terminal and a first terminal of the capacitor; - a second capacitive charging switch connected between the first terminal of the capacitor and the second output terminal; - a third switch for capacitive charging connected between the second output terminal and a second terminal of the capacitor; and - a fourth switch for capacitive charging, which is connected between the second terminal of the capacitor and the reference potential. [17] A method of operating a power converter having an input terminal, a capacitor, a first output terminal, a second output terminal, an output switch between the first output terminal and the second output terminal, and an inductor, wherein a first terminal of the inductor is connected to the first output terminal, the method comprising: - Connecting an input switch between the input terminal and a first terminal of the capacitor; - connecting a first capacitive charging switch between the first terminal of the capacitor and the second output terminal; - connecting a second capacitive charging switch between the second output terminal and a second terminal of the capacitor; - Connecting a ground switch between the second terminal of the capacitor and a reference potential; - connecting a first switch for inductive charging between the first terminal of the capacitor and a second terminal of the inductor; and - Connecting a second switch for inductive charging between the second terminal of the inductor and the second terminal of the capacitor. [18] The method of claim 17, further comprising converting the electrical power at the input terminal into - electrical power for supplying an external electronic device at the first output terminal with energy or in - electrical power for charging an external energy storage device at the second output terminal. [19] A method according to claim 17 or 18, further comprising in a capacitive charging mode: - Switching off the output switch, the first inductive charging switch and the second inductive charging switch and - Controlling the remaining switches so that an external storage device connected to the second output terminal is charged with a constant charging current. [20] A method according to any one of claims 17 to 19, further comprising in an inductive charging mode - Turning off the first capacitive charging switch and the second capacitive charging switch and - Controlling the remaining switches to regulate an output voltage at the first output terminal. [21] A method according to any one of claims 17 to 20, further comprising - Turn on the output switch and - Controlling the remaining switches so that an external storage device connected to the second output terminal is charged with a constant charging voltage. [22] A method of operating a power converter having an input terminal, a capacitor, a first output terminal, a second output terminal, an output switch between the first output terminal and the second output terminal, and an inductor, wherein a first terminal of the inductor is connected to the first output terminal, the method further comprising: - Connecting a first switch for inductive charging between the input terminal and a second terminal of the inductor; - Connecting a second switch for inductive charging between the second terminal of the inductor and a reference potential; - connecting a first capacitive charging switch connected to the input terminal and a first terminal of the capacitor; - Connecting a second switch for capacitive charging between the first terminal of the capacitor and the second output terminal; - connecting a third switch for capacitive charging between the second output terminal and a second terminal of the capacitor; and - Connecting a fourth switch for capacitive charging between the second terminal of the capacitor and the reference potential.

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