Switching converter and method

Abstract

A switching converter in one embodiment includes: an input stage; an output stage for providing an output voltage; a capacitive coupling stage for coupling the input stage and the output stage; a first switching stage configured to switch between a first state and a second state, in which an input voltage is provided to the input stage in the first state and in which the input voltage is not provided to the input stage in the second state; a second switching stage configured to switch between a first state and a second state, in which a reference voltage is provided to the output stage in the first state and in which the reference voltage is not provided to the output stage; and a voltage regulation stage configured to set a target voltage across the input stage after the second switching stage switches from the first state to the second state and before the first switching stage switches from the second state to the first state.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of Italian Application No. 102020000005971, filed on March 20, 2020, which is incorporated herein by reference. Technical Field

[0003] Embodiments of the present invention generally relate to the field of switching converters and methods. Specifically, embodiments of the present invention relate to DC-DC switching converters and methods for converting a DC input voltage into a DC output voltage that differs from the input voltage. More specifically, embodiments of the present invention relate to a switching converter, such as a zeta converter, and methods, in which the output voltage is lower or higher than the input voltage depending on the duty cycle of an oscillating signal. Background Art

[0004] A direct current to direct current (DC-DC) switching converter can be used in any electronic system that includes a power source (such as a battery) and one or more electronic / electromechanical components, each operating at its own voltage: in such an electronic system, the DC-DC switching converter can be configured to generate multiple controlled output voltages from a (single) input voltage provided by the power source.

[0005] This saves space by eliminating the need for multiple power supplies within an electronic system to power its different components.

[0006] More recently, zeta converters have been developed in which, depending on the duty cycle of an oscillating signal (usually a square wave signal), the output voltage is lower or higher than the input voltage.

[0007] A conventional zeta converter includes an inductor (or inductor-capacitor) input stage for receiving an input voltage, an inductor (or inductor-capacitor) output stage for providing an output voltage, a capacitive coupling stage for coupling the input stage and the output stage to each other, a high-side switch, and a low-side switch.

[0008] Under control of the oscillating signal, the high-side switch is configured to switch between a first state (or an on-state) in which the input voltage is delivered to the input stage and a second state (or an off-state) in which the input voltage is blocked from being delivered to the input stage, and the low-side switch is configured to switch between a first state (or an on-state) in which the reference voltage is delivered to the output stage and a second state (or an off-state) in which the reference voltage is blocked from being delivered to the output stage. Summary of the Invention

[0009] The applicant has appreciated that conventional zeta converters are unsatisfactory for modern technological requirements, in particular for applications requiring high efficiency.

[0010] In practice, the Applicant has recognized that the maximum operating current flowing through the high-side switch and the low-side switch is extremely high compared to the output current delivered to the electrical load coupled to (the output stage of) the zeta converter, the maximum operating voltage across the output stage is significantly higher than the output voltage, and the minimum operating voltage across the input stage is far from the output voltage: this leads to very high commutation losses, especially at the high switching frequencies of the Zeta converter.

[0011] The applicant has understood that when the duty cycle of the oscillating signal is higher than 0.5 (boost condition), and when the low-side switch is switched from the on-state to the off-state and then the high-side switch is switched from the off-state to the on-state, the commutation losses increase: in this case, the high-side switch will experience an initial voltage drop and current that can be higher than 30V and higher than 10A based on current electrical standards, which will result in an initial power consumption higher than 300W.

[0012] Furthermore, when in practice the high-side switch is implemented by a metal oxide semiconductor (MOS) transistor, at least initially, the intrinsic diode between the drain and source terminals of the MOS transistor is in direct conduction: therefore, due to the reverse recovery time, the current flowing through the high-side switch can be even higher, resulting in an initial power dissipation that can be even higher than 500 W.

[0013] Applicants have encountered the above-mentioned problems and have designed a switching converter that includes a voltage regulation stage that is configured to set a target voltage across an input stage after a low-side switching stage switches from an on-state to an off-state and before a high-side switching stage switches from an off-state to an on-state, with substantially no power dissipation (i.e., no or substantially no power dissipation by one or more components of the voltage regulation stage).

[0014] One or more aspects of the invention are set out in the independent claims and advantageous features of the invention are pointed out in the dependent claims, the wording of which is incorporated herein by reference (and reference will apply mutatis mutandis to any other aspect of the invention for which any advantageous features are provided).

[0015] More specifically, one aspect of the present invention relates to a switching converter for converting a DC input voltage into a DC output voltage.

[0016] According to an embodiment, a switching converter comprises:

[0017] an input stage for receiving an input voltage;

[0018] An output stage for providing an output voltage;

[0019] a capacitive coupling stage for coupling the input stage and the output stage to each other;

[0020] a first switching stage configured to switch between a first state in which the input voltage is allowed to be supplied to the input stage and a second state in which the input voltage is blocked from being supplied to the input stage;

[0021] a second switching stage configured to switch between a first state in which the reference voltage is allowed to be supplied to the output stage and a second state in which the reference voltage is blocked from being supplied to the output stage;

[0022] The voltage regulation stage is configured to set a target voltage across the input stage after the second switching stage is switched from the first state to the second state and before the first switching stage is switched from the second state to the first state.

[0023] According to an embodiment, which is additionally or alternatively to any of the features of the preceding embodiments, the voltage regulation stage comprises an LC stage.

[0024] According to an embodiment, which is additionally or alternatively characterized by any of the features of the preceding embodiments, the voltage regulation stage comprises a third switching stage configured to switch between a first state in which the target voltage is allowed to be set across the input stage by the LC stage and a second state in which the target voltage is prevented from being set across the input stage.

[0025] According to an embodiment, which is characterized in addition to or instead of any of the features of the preceding embodiments, the voltage regulation stage comprises a control module configured to:

[0026] In a case where the first switching stage is in the second state, when the second switching stage is switched from the first state to the second state, the third switching stage is switched from the second state to the first state.

[0027] switching the third switching stage from the first state back to the second state when the target voltage across the input stage has been set; and

[0028] When the second switching stage is in the second state, when the third switching stage switches back from the first state to the second state, the first switching stage is switched from the second state to the first state.

[0029] According to an embodiment, which is additionally or alternatively to any of the features of the preceding embodiments, the LC stage is connected in parallel to the input stage when the third switching stage is in the first state.

[0030] According to an embodiment, which is additionally or alternatively to any of the features of the preceding embodiments, the switching device further comprises at least one limiting stage for limiting oscillations across the LC stage.

[0031] According to an embodiment, which is additionally or alternatively to any of the features of the preceding embodiments, at least one limiting stage comprises a diode element across the first switching stage and the third switching stage for limiting forward oscillations across the LC stage.

[0032] According to an embodiment, which is characterized in addition to or instead of any of the features of the preceding embodiments, at least one restriction level further comprises:

[0033] A fourth switching stage across the LC stage is used to limit negative oscillations across the LC stage.

[0034] According to an embodiment, which is additionally or alternatively to any of the features of the preceding embodiments, the LC stage is connected in parallel to the output stage when the third switching stage is in the first state.

[0035] According to an embodiment, which is additionally or alternatively to any of the features of the preceding embodiments, the switching converter is a zeta converter.

[0036] Another aspect of the present invention relates to a system comprising one or more such switching converters.

[0037] Another aspect of the present invention relates to a method for converting a DC input voltage into a DC output voltage in a switching converter. The switching converter comprises:

[0038] an input stage for receiving an input voltage;

[0039] An output stage for providing an output voltage;

[0040] a capacitive coupling stage for coupling the input stage and the output stage to each other;

[0041] a first switching stage configured to switch between a first state in which the input voltage is allowed to be supplied to the input stage and a second state in which the input voltage is blocked from being supplied to the input stage;

[0042] a second switching stage configured to switch between a first state in which the reference voltage is allowed to be supplied to the output stage and a second state in which the reference voltage is prevented from being supplied to the output stage;

[0043] According to one embodiment, the method includes: switching the second switching stage from a first state to a second state (the first switching stage is in the second state); setting a target voltage across the input stage; and then switching the first switching stage from the second state to the first state (the second switching stage is in the second state). BRIEF DESCRIPTION OF THE DRAWINGS

[0044] These and other features and advantages of the present invention will become apparent from the following description of some exemplary and non-limiting embodiments. For a better understanding, the following description should be read with reference to the accompanying drawings, in which:

[0045] Figure 1 shows a schematic circuit diagram of a switching converter according to an embodiment of the present invention, and

[0046] Figure 2 Schematic trends of control signals of a switching converter according to an embodiment of the present invention are shown. DETAILED DESCRIPTION

[0047] With reference to the accompanying drawings, Figure 1 FIG. 2 shows a schematic circuit diagram of a switching converter 100 according to an embodiment of the present invention.

[0048] Hereinafter, when one or more features of the switching converter 100 are introduced by the wording “according to an embodiment”, they should be interpreted as supplementary or alternative features to any previously introduced features, unless otherwise stated and / or unless there is obvious incompatibility between the feature combinations.

[0049] According to an embodiment, the switching converter 100 is a DC-DC switching converter, that is, a converter configured to convert a direct current (DC) input voltage V IN Converted into DC output voltage V OUT The switching converter (output voltage V OUT With input voltage V IN different).

[0050] According to an embodiment, the switching converter is a Zeta converter, ie a converter in which the switching frequency depends on the oscillation signal V OSC The duty cycle makes the output voltage V OUT Lower or higher than the input voltage V IN of a switching converter (discussed below).

[0051] Without loss of generality, switching converter 100 may be used in any electronic system that includes a power source (such as a battery pack of photovoltaic cells) and one or more electronic / electromechanical components, each of which operates at its own voltage: in such an electronic system, switching converter 100 (or more thereof) may be configured to generate multiple controlled output voltages from a single input voltage provided by the power source (thus saving space by avoiding the need for multiple power supplies within the electronic system to power its different components). Examples of such electronic systems include battery chargers or audio power amplifiers.

[0052] According to an embodiment, the switching converter 100 includes a circuit that provides an input voltage V IN Input terminal T IN and provides output voltage V OUT Output terminal T OUT .

[0053] According to an embodiment, the switching converter 100 includes a first switching stage, for example, a first switching element 105 H (hereinafter referred to as the high-side switch); and a second switching stage, for example, the second switching element 105 L (hereinafter referred to as low-side switch). In the following, when the high-side switch 105 H and low-side switch 105 L The distinction between the two is irrelevant to the understanding of the present invention, the high-side switch 105 H and low-side switch 105 L It will also be switched by switch 105 H , 105 L To express concisely.

[0054] Switch 105 H , 105 L They are illustrated in the figures by the same general representation, since their specific implementation is not relevant to the understanding of the present invention.

[0055] According to an embodiment, each switch 105 H , 105 L including for receiving respective control signals V CTRL,H 、V CTRL,L control terminals, and their respective control signals V CTRL,H 、V CTRL,L The value of (i.e., the value it takes) can electrically couple the first terminal and the second terminal to each other.

[0056] According to an embodiment, each control signal V CTRL,H 、V CTRL,L It is a digital signal, ie, a signal that can adopt a low logic level (eg, corresponding to a reference voltage or ground voltage, such as 0V) and a high logic level (eg, corresponding to a positive voltage higher than the reference voltage, such as 3.4V).

[0057] According to an embodiment, each control signal V CTRL,H 、V CTRL,L By the oscillation signal V OSC Provide (eg, generate).

[0058] According to an embodiment, the oscillation signal V OSC is a square wave signal with a duty cycle D. According to an embodiment, the oscillation signal V OSC The duty cycle D of the switching converter 100 is dynamically variable, thereby changing the conversion factor (V OUT / V IN ).

[0059] According to an embodiment, depending on the respective control signal V CTRL,H 、V CTRL,LThe value of each switch is 105 H , 105 L may be in an on or conducting state, wherein the respective first and second terminals are electrically coupled to each other (thereby allowing current to flow through the switch 105). H , 105 L ), and an open or disconnected state, wherein the respective first and second terminals are electrically coupled to each other (thereby preventing any current from flowing through the switch 105 H , 105 L ).

[0060] According to an embodiment, the control signal V CTRL,H 、V CTRL,L is designed so that the switch 105 H , 105 L are not all in the on-state: However, as better discussed below, unlike typical known zeta converters, where the control signal V CTRL,H 、V CTRL,L are mutually inverted square wave signals, that is, square wave signals with a fixed phase shift of 180° (usually, the control signal V CTRL,H 、V CTRL,L One of them is the oscillation signal V OSC , control signal V CTRL,H 、V CTRL,L The other is the oscillation signal V OSC The control signal V CTRL,H 、V CTRL,L are square wave signals that are dynamically phase-shifted with respect to each other (ie, there is no fixed, predetermined phase shift between them).

[0061] According to an embodiment, the high-side switch 105 H The first terminal is electrically coupled (eg, directly connected) to the input terminal T IN .

[0062] According to an embodiment, the low-side switch 105 L The second terminal of the MOSFET is electrically coupled (eg, directly connected) to a reference terminal T providing a reference voltage (eg, 0 V). GND .

[0063] According to an embodiment, not shown, the high-side switch 105 H including a PMOS transistor, and a low-side switch 105 L Including NMOS transistors.

[0064] According to an embodiment, the switching converter 100 includes an input stage for receiving an input voltage V IN (From input terminal T IN ); and an output stage for providing an output voltage VOUT (For output terminal T OUT ).

[0065] According to an embodiment, the input stage of the switching converter 100 is an inductive input stage. For example, the input stage of the switching converter 100 includes an inductor element 110. Lin (hereinafter referred to as input inductor).

[0066] According to an embodiment, the input inductor 110 has a configuration electrically coupled (eg, directly connected) to the high-side switch 105. H The first terminal of the second terminal of the first terminal and the second terminal of the second terminal are electrically coupled (eg, directly connected) to the reference terminal T GND The second terminal.

[0067] According to an embodiment, the output stage of the switching converter 100 includes an inductor element 110 Lout , hereinafter referred to as the output inductor.

[0068] According to an embodiment, the output inductor 110 Lout having a first terminal electrically coupled (eg, directly connected) to the low-side switch 105 L The first terminal and the second terminal are electrically coupled (eg, directly connected) to the output terminal T OUT .

[0069] Therefore, in the exemplary embodiment considered, the high-side switch 105 H In the on state, the input voltage V IN is allowed to be supplied to the input stage, and the high side switch 105 H In the disconnected state, the input voltage V IN is blocked from being supplied to the input stage.

[0070] According to an embodiment, the output stage of the switching converter 100 includes a capacitor element 115 Cout , hereinafter referred to as the output capacitor.

[0071] According to an embodiment, the output capacitor 115 Cout Having a first terminal electrically coupled (eg, directly connected) to the output terminal T OUT (and thus electrically coupled to the output inductor 110 Lout The second terminal of the reference terminal T is electrically coupled (eg, directly connected) to the reference terminal T GND .

[0072] Therefore, in the exemplary embodiment considered, the low-side switch 105 L In the on state, the reference voltage is allowed to be supplied to the output stage and the low side switch 105 LIn the off state, the reference voltage is blocked from being supplied to the output stage.

[0073] According to an embodiment, switching converter 100 includes a capacitive coupling stage for coupling an input stage and an output stage to each other.

[0074] According to an embodiment, the capacitive coupling stage comprises a capacitor element 120 CC , hereinafter referred to as coupling capacitor.

[0075] According to an embodiment, the coupling capacitor 120 CC having a first terminal electrically coupled (eg, directly connected) to the input inductor 110 Lin The first terminal (and thus electrically coupled to the high-side switch 105 H ), and a second terminal thereof, electrically coupled (eg, directly connected) to the output inductor 110 Lout The first terminal (and thus electrically coupled to the low-side switch 105 L first terminal).

[0076] As mentioned above, the switching converter 100 can be used in any electronic system. According to an embodiment, the switching converter 100 is configured to be electrically coupled to one or more modules of the electronic system. In the figure, such a module is conceptually represented by an equivalent resistor element R LOAD (hereinafter referred to as the load resistor) to represent the equivalent resistor element R LOAD having an output terminal T electrically coupled (eg, directly connected) to the switching converter 100. OUT and electrically coupled (eg, directly connected) to a reference terminal T GND The second terminal.

[0077] The switching converter disclosed so far can basically be regarded as a typical, known zeta converter, whose basic relationship is quoted here below (and is still valid for the switching converter according to the embodiment of the present invention):

[0078] - As input voltage V IN The output voltage V OUT It can be expressed by the following relationship:

[0079] - The output inductor 110 Lout The maximum operating voltage at the first terminal V O,max (High side switch 105 H In the on state, the low-side switch 105 L is in the off state), and at the output inductor 110 Lout The minimum operating voltage at the first terminal V O,min(High side switch 105 H In the off state, the low-side switch 105 L In the on state) can be expressed by the following relationship:

[0080]

[0081] V O,min =0

[0082] -Input inductor 110 Lin The maximum operating voltage at the first terminal V I,min (High side switch 105 H In the on state, the low-side switch 105 L is in the off state), and at the input inductor 110 Lin The minimum operating voltage at the first terminal V I,min (High side switch 105 H In the off state, the low-side switch 105 L In the on state) can be expressed by the following relationship:

[0083] V I,max =V IN

[0084]

[0085] - flows through the load resistor R LOAD The output current I OUT It can be expressed by the following relationship:

[0086]

[0087] Among them, R load Represents the load resistance R LOAD The resistance value;

[0088] - flows through the low-side switch 105 L Average I L,avg Operating current and maximum I L,max The operating current can be expressed by the following relationship:

[0089]

[0090]

[0091] - flows through the high side switch 105 H Average I H,avg Operating current and maximum I H,max The operating current can be expressed by the following relationship:

[0092]

[0093]

[0094] The applicant has recognized that known zeta converters (the main relationships of which are cited above) have low efficiencies.

[0095] Indeed, given this, just as an example:

[0096] V IN =10V

[0097] D = 0.7

[0098] R LOAD =1Ω

[0099] Based on the relationships cited above, the results are as follows:

[0100] V OUT =23.3V

[0101] V O,max =32.86V

[0102] V I,min =-22.86V

[0103] I OUT =2.33A

[0104] I H,max =I L,max =10.95A

[0105] That is, with the output current I OUT Compared to the current flowing through switch 105 H , 105 L Maximum operating current I H,max , I L,max Extremely high, maximum operating voltage V O,max Significantly higher than the output voltage V OUT , and the minimum operating voltage V I,min With the output voltage V OUT The phase difference is very large: This leads to very high commutation losses, especially at high switching frequencies.

[0106] The applicant has learned that when D>0.5 (boost condition), and when the low-side switch 105 L The high-side switch 105 switches from the on state to the off state and H When switching from the off state to the on state, a critical rise in commutation losses occurs: in this case, the output inductor 110 Lout The first terminal will experience a voltage from the minimum operating voltage V O,min To the maximum operating voltage V O,maxThe sudden voltage excursion (32.86V in the example under discussion) and the high side switch 105 H will experience an initial voltage drop of 32.86V across it (i.e., V IN -(V IN -V O,max )=V O,max ) and an initial power consumption of 359.8W (32.86V*10.95A).

[0107] In addition, when in actual conditions, the high side switch 105 H This is achieved by a MOS transistor, the intrinsic diode between the drain and source terminals of which is at least initially in direct conduction: therefore, due to the reverse recovery time, the current flowing through the high-side switch 105 H The current can also be greater than the maximum operating current I H,max 2 or 3 times higher (thus resulting in an initial power consumption that can rise to over 500W).

[0108] Switching converter 100 according to an embodiment of the present invention is intended to overcome or at least significantly reduce these problems as discussed below.

[0109] In accordance with the principles of the present invention, a switching converter 100 includes a voltage regulation stage configured to provide a voltage regulation between the low-side switch 105 and the low-side switch 106. L After switching from the on state to the off state and the high side switch 105 H Before switching from the off state to the on state, set the input inductor 110 Lin The target voltage V I,TH .

[0110] According to an embodiment, the voltage regulation stage comprises an inductor-capacitor (LC) stage.

[0111] According to an embodiment, the voltage regulation stage includes an auxiliary switching stage configured to switch between an on or conducting state and an off or disconnected state, wherein in the on or conducting state the target voltage V I,TH is allowed across the input inductor 110 Lin The target voltage V is set by the LC stage and in the off state or disconnected I,TH is blocked across the input inductor 110 Lin set up.

[0112] According to an embodiment, the LC stage comprises an auxiliary inductor element 110 Laux , hereinafter referred to as the auxiliary inductor.

[0113] According to an embodiment, the auxiliary inductor 110 Laux having an electrical coupling (eg, direct connection) to the auxiliary switching element 105AUX The first terminal of the second terminal is electrically coupled (eg, directly connected) to the reference terminal T GND The second terminal.

[0114] According to an embodiment, the capacitive effect of the LC stage is due to the coupling capacitor C C The parasitic capacitor C associated with the first terminal and the second terminal H ,C L , the parasitic capacitor mainly includes the high-side switch 105 H The intrinsic capacitor and low-side switch 105 L The intrinsic capacitor.

[0115] According to an embodiment, the auxiliary switching stage comprises an auxiliary switching element 105 AUX , hereinafter referred to as the auxiliary switch. According to an embodiment, the auxiliary switch 105 AUX having an electrical coupling (eg, direct connection) to the input inductor 110 Lin (and thus electrically coupled to the high side switch 105 H and a second terminal) of the first terminal, a second terminal, and a second terminal for receiving respective control signals V CTRL,AUX control terminals.

[0116] According to an embodiment, the auxiliary switch 105 AUX Includes bidirectional switching (also known as analog switching or PETR switching).

[0117] According to an embodiment, not shown, the auxiliary switch 105 AUX and auxiliary inductor 110 Laux are electrically coupled to each other in reverse order (ie, by electrically coupling (eg, directly connecting) to the auxiliary inductor 110 Laux The first terminal of the reference terminal T is electrically coupled (eg, directly connected) to the reference terminal T GND The second terminal of the auxiliary inductor 110 is electrically coupled to each other (eg, directly connected). Laux The second terminal and the auxiliary switch 105 AUX first terminal).

[0118] Similar to switch 105 H , 105 L , auxiliary switch 105 AUX The first terminal and the second terminal can be controlled according to the control signal V CTRL,AUX The values of are electrically coupled to each other.

[0119] According to an embodiment, depending on the control signal V CTRL,AUX The value of auxiliary switch 105 AUXA conductive state may be adopted in which the respective first and second terminals are electrically coupled to each other (thereby allowing current to flow through the auxiliary switch 105). AUX , and thus allows the target voltage V I,TH is passed through the LC stage across the input inductor 110 Lin setting), or adopting an open state in which the respective first and second terminals are electrolytically coupled to each other (thereby preventing any current from flowing through the auxiliary switch 105 AUX , and thus prevents the cross-input inductor 110 Lin Set the target V I,TH Voltage).

[0120] According to an embodiment, the control signal V CTRL,AUX It is a digital signal, ie, a signal that can adopt a low logic level (eg, corresponding to a reference voltage or a ground voltage) or a high logic level (eg, corresponding to a positive voltage higher than the reference voltage, such as 3.4V).

[0121] According to an embodiment, the oscillation signal V OSC To provide (eg, generate) a control signal V CTRL,AUX .

[0122] According to an exemplary embodiment, when the auxiliary switch 105 AUX When in the on state, the LC stage (specifically, the auxiliary inductor 110 Laux ) and the input stage (specifically, the input inductor 110 Lin ) are connected in parallel.

[0123] According to an exemplary embodiment, the auxiliary switch 105 AUX and LC stage (specifically, auxiliary inductor 110 Laux ) are connected in series with each other and with the input stage (specifically, the input inductor 110 Lin )in parallel.

[0124] According to an alternative embodiment, not shown, the auxiliary switch 105 AUX and LC stage (specifically, auxiliary inductor 110 Laux ) are connected in series with each other and across the high side switch 105 H and coupling capacitor 120 CC (For example, using auxiliary switch 105 AUX is electrically coupled to the high side switch 105 H The first terminal and the auxiliary inductor 110 Laux The first terminal and the second terminal of the first terminal, and the auxiliary inductor 110 Laux The electrical coupling to the coupling capacitor 120 CC the second terminal of the second terminal).

[0125] According to an embodiment, switching converter 100 includes a control module (eg, a microcontroller) 125 .

[0126] According to an embodiment, the control module 125 is configured to receive the oscillation signal V OSC , and from the oscillation signal V OSC Provide (eg, generate) a control signal V CTRL,H ,V CTRL,L ,V CTRL,AUX .

[0127] According to an embodiment, the control module 125 is further configured to Lin The first input terminal receives a voltage V I (hereinafter referred to as the operating voltage VI) or its indication, and is also based on the received operating voltage V I Provide (eg, generate) a control signal V CTRL,H 、V CTRL,L 、V CTRL,AUX .

[0128] According to an embodiment, the control module 125 is configured to execute Lin The operating voltage at the first input terminal (such as the operating voltage V I shown) and the target voltage V I,TH According to an embodiment, the target voltage V I,TH At 0V and input voltage V IN According to an embodiment, the target voltage V I,TH According to the embodiment, the target voltage V I,TH is stored in an appropriate memory location of the control module 125. According to an embodiment, the target voltage V I,TH Can be set (and / or changed) by the user.

[0129] In summary, according to an embodiment, the control module 125 is configured to: L Switching from the on state to the off state (high side switch 105 H In the disconnected state), turn on the auxiliary switch 105 AUX Switching from the off state to the on state; when the input inductor 110 Lin When the target voltage has been set (i.e., when V I ≥V I,TH When the auxiliary switch 105 AUX Switching from the on state back to the off state; and when the auxiliary switch 105 AUX Switching from the on state back to the off state (low side switch 105 L is still in the disconnected state), the high-side switch 105H Switch from the off state to the on state.

[0130] Combine Figure 2 , Figure 2 shows the oscillating signal V according to an embodiment of the present invention OSC and the control signal V CTRL,H , V CTRL,L , V CTRL,AUX schematic trends. Specifically, only exemplary is shown in the figure, related to the switching of the low-side switch 105 L from the off state to the on state, and related to the switching of the high-side switch 105 H which has been shown exemplarily from the on state to the off state, the oscillating signal V OSC and the control signals V CTRL,H , V CTRL,L , V CTRL,AUX trends, in fact, as described above, this is the worst case in terms of commutation loss and power consumption.

[0131] According to an embodiment, the control module 125 operates as follows.

[0132] When the oscillating signal V OSC is at a low logic level (T0 < t < T1), the control signal V CTRL,L is at a high logic level, and the control signals V CTRL,H , V CTRL,AUX are at low logic levels. In this case, the low-side switch 105 L is in the on state, the high-side switch 105 H and the auxiliary switch 105 AUX are in the off state, and the operating voltage V I is equal to the minimum operating voltage V I,min (i.e., ).

[0133] When the oscillating signal V OSC switches from the low logic level to the high logic level (t = T1), the control signal V CTRL,L switches from the high logic level to the low logic level (the control signal V CTRL,L is thus the inverted signal V REF of the control signal, the control signal V CTRL,AUX switches from the low logic level to the high logic level, and the control signal V CTRL,H remains at the low logic level. In this case, the low-side switch 105 L switches from the on state to the off state, the high-side 105 H switch remains in the off state, and the auxiliary switch 105 AUXSwitches from the off state to the on state. In this configuration, due to the auxiliary inductor 110 Laux and coupling capacitor 120 CC The parasitic capacitor C associated with the first terminal and the second terminal H ,、C L The resonance effect between the working voltage V I From the minimum operating voltage V I,min Gradually increase.

[0134] When the operating signal V I and the target voltage V I,TH The comparison result between the working signal V I Equal to or higher than the target voltage V I,TH (t=T2), the control signal V CTRL,AUX Switching from a high logic level to a low logic level, the control signal V CTRL,H Switches from low logic level to high logic level, and the control signal V CTRL,L In this case, the high side switch 105 H Switching from the off state to the on state, the auxiliary switch 105 AUX Switches from the on state to the off state, and the low-side switch 105 L In this configuration, the operating voltage V I From the target voltage V I,TH rises (essentially instantaneously) to the input voltage V IN : Therefore, in V IN =10V and V I,TH = 0, the high-side switch 105 H A voltage drop of 10V is experienced across it (instead of 32.86V as in known switching converters), so power consumption is significantly reduced.

[0135] As mentioned above, when the auxiliary switch 105 AUX In the on state (and the low side 105 L and high side 105 H When the switch is in the off state), due to the auxiliary inductor 110 Laux and parasitic capacitor C H 、C L The resonance effect between the working voltage V I From the minimum operating voltage V I,min Gradually increase.

[0136] Resonant frequency f r is given by:

[0137]

[0138] Among them, L aux Auxiliary inductor 110 Laux The inductance value, and C H and C L They represent the parasitic capacitors C H and C L capacitance value.

[0139] According to an embodiment, the resonant frequency f of the LC stage r is higher, preferably much higher, than the switching frequency of the switching converter 100. To achieve this, the auxiliary inductor 110 Laux The inductance value can be 110 higher than the input inductor Lin The inductance value is much lower: As an example only, L aux =20nH, L in =2μH.

[0140] According to an embodiment, the resonant frequency f of the LC stage r The ratio between the switching frequency and the switching frequency of the switching converter 100 is at least equal to 10, or higher than 10.

[0141] The invention allows reducing the commutation losses with a limited number of active components of the system and practically without adding passive components: indeed, the only passive component added is the auxiliary inductor 110 Laux ) can have values that can be obtained by routing of a printed circuit or in integrated form (in the case of an integrated system).

[0142] According to an embodiment, the switching converter 100 further includes one or more limiting stages for limiting the current across the LC stage (ie, across the auxiliary inductor 110). Laux ) oscillation.

[0143] According to an embodiment, the limiting stage comprises a positive oscillation limiting stage for limiting the oscillation across the LC stage (ie across the auxiliary inductor 110 Laux According to an embodiment, the positive oscillation limiting stage is arranged across the high side switch 105 H and auxiliary switch 105 AUX According to an embodiment, the positive oscillation limiting stage comprises a diode element 130 D (or other clamping elements), the diode element 130 D having an electrical coupling (eg, a direct connection) to the high-side switch 105 H The cathode terminal of the first terminal of the switching converter 100 (and thus electrically coupled to the input terminal of the switching converter 100) and electrically coupled (eg, directly connected) to the auxiliary switch 105 AUX The second terminal of the auxiliary inductor 110 is electrically coupled to the Lauxan anode terminal of a first terminal of the device.

[0144] According to an embodiment, the limiting stage comprises a negative oscillation limiting stage for limiting the current across the LC stage (ie across the auxiliary inductor 110 Laux According to an embodiment, the negative oscillation limiting stage is arranged across the auxiliary inductor 110 Laux According to an embodiment, the negative oscillation limiting stage comprises a further switching element 135 (hereinafter, limit switch), for example a bilateral switch, which has an electrical coupling (eg, direct connection) to the auxiliary inductor 110 Laux The first terminal (and thus electrically connected to the diode element 130 D A first terminal of the anode terminal of the transistor is electrically coupled (eg, directly connected) to a reference terminal T GND The second terminal is used to receive the corresponding control signal control terminals.

[0145] Similar to switch 105 H , 105 L , 105 AUX , the first terminal and the second terminal of the limit switch 135 can be controlled according to the control signal The values of are electrically coupled to each other.

[0146] According to an embodiment, depending on the control signal Depending on the value of , the limit switch 135 can adopt an "on" state, in which the corresponding first terminal and the second terminal are electrically coupled to each other (thereby allowing current to flow through the limit switch 135), or an "off" state, in which the corresponding first terminal and the second terminal are electrically decoupled from each other (thereby preventing any current from flowing through the limit switch 135).

[0147] According to an embodiment, the control signal It is a digital signal, ie, a signal that can adopt a low logic level (eg, corresponding to a reference voltage or a ground voltage) or a high logic level (eg, corresponding to a positive voltage higher than the reference voltage, such as 3.4V).

[0148] According to an embodiment, the control signal By the oscillation signal V OSC is provided (eg, generated).

[0149] According to an embodiment, the control signal is the control signal V CTRL,AUX The control module 125 is configured to be, for example, the inverted signal of the oscillation signal V OSC Provide (eg, generate) a control signal V CTRL,H 、V CTRL,L 、V CTRL,AUX 、

[0150] Naturally, in order to meet local and specific requirements, a person skilled in the art may apply many logical and / or physical modifications and substitutions to the above invention. More specifically, although the present invention has been described with a certain degree of particularity with reference to the preferred embodiments of the invention, it should be understood that various omissions, substitutions and changes in form and details and in other embodiments are possible. In particular, different embodiments of the present invention can even be practiced without the specific details set forth in the preceding description to provide a more comprehensive understanding of the invention. On the contrary, well-known features may have been omitted or simplified so as not to interfere with the description by unnecessary details. Moreover, it is expressly intended that the specific elements and / or method steps described in conjunction with any disclosed embodiment of the present invention may be combined in any other embodiment.

[0151] In particular, similar considerations apply if the switching converter has a different structure or includes equivalent components. In any case, any of its components can be divided into several elements, or two or more components can be combined into one element. In addition, each component can be replicated to support parallel execution of the corresponding operations. It should also be noted that (unless otherwise stated) any interaction between different components generally does not need to be continuous and can be direct or indirect through one or more intermediaries.

[0152] For example, although it has been explicitly mentioned above that the LC stage is connected in parallel to the input stage, by considering that when the auxiliary switch 105 AUX The LC stage (specifically, the auxiliary inductor 110) connected in parallel to the output stage when in the on state Laux ) (Specifically, in the output inductor 110 Lout The first terminal and reference terminal T GND In this case, the output inductor 110 Lout The operating voltage or an indication thereof at the first input terminal of may be received at the control module 125, and the control module 125 may be configured to perform a comparison between the operating voltage and a target voltage based on the oscillation signal V OSC and the operating voltage to generate the control signal V CTRL,H 、V CTRL,L 、V CTRL,AUX 、

[0153] Although the present invention has been described with reference to illustrative embodiments, this description is not intended to be construed in a limiting sense. Various modifications and combinations of the exemplary embodiments, as well as other embodiments of the present invention, will be apparent to those skilled in the art by reference to the description. It is therefore intended that the appended claims cover any such modifications or embodiments.

Claims

1. A switching converter for converting a DC input voltage into a DC output voltage, wherein the switching converter comprises: An input stage, configured to receive the input voltage; an output stage, for providing the output voltage; a capacitive coupling stage for coupling the input stage and the output stage to each other; a first switching stage configured to switch between a first state in which the input voltage is allowed to be supplied to the input stage and a second state in which the input voltage is blocked from being supplied to the input stage; a second switching stage configured to switch between a third state in which a reference voltage is allowed to be supplied to the output stage and a fourth state in which the reference voltage is prevented from being supplied to the output stage; and A voltage regulation stage is configured to set a target voltage across the input stage after the second switching stage is switched from the third state to the fourth state and before the first switching stage is switched from the second state to the first state.

2. The switching converter of claim 1 , wherein the voltage regulation stage comprises: Inductor-capacitor LC stage; a third switching stage configured to switch between a fifth state in which the target voltage is allowed to be set across the input stage via the LC stage, and a sixth state in which the target voltage is prevented from being set across the input stage; and The control module is configured as follows: When the first switching stage is in the second state, when the second switching stage is switched from the third state to the fourth state, switching the third switching stage from the sixth state to the fifth state; switching the third switching stage from the fifth state back to the sixth state when the target voltage across the input stage has been set; and When the third switching stage is switched from the fifth state back to the sixth state in a case where the second switching stage is in the fourth state, the first switching stage is switched from the second state to the first state. 3 . The switching converter of claim 2 , wherein the LC stage is connected in parallel with the input stage when the third switching stage is in the fifth state.

4. The switching converter of claim 2, further comprising at least one limiting stage for limiting oscillations across the LC stage. 5 . The switching converter of claim 4 , wherein the at least one limiting stage comprises a diode element across the first switching stage and the third switching stage for limiting positive oscillations across the LC stage.

6. The switching converter of claim 5 , wherein the at least one limiting stage further comprises: A fourth switching stage across the LC stage is provided for limiting negative oscillations across the LC stage.

7. The switching converter according to claim 2, wherein: When the third switching stage is in the fifth state, the LC stage is connected in parallel with the output stage. The switching converter of claim 1 , wherein the switching converter is a zeta converter.

9. An electronic system comprising: a power supply configured to generate a source voltage; a first electronic / electromechanical component configured to operate at a first voltage; a second electronic / electromechanical component configured to operate at a second voltage different from the first voltage; a first switching converter configured to receive the source voltage from the power supply and provide the first voltage to the first electronic / electromechanical component; and a second switching converter configured to receive the source voltage from the power supply and provide the second voltage to a second electronic / electromechanical component; Each of the first switching converter and the second switching converter includes: an input stage for receiving the source voltage; an output stage, configured to provide the first voltage or the second voltage respectively; a capacitive coupling stage for coupling the input stage and the output stage to each other; a first switching stage configured to switch between a first state in which the source voltage is allowed to be supplied to the input stage and a second state in which the source voltage is blocked from being supplied to the input stage; a second switching stage configured to switch between a third state in which a reference voltage is allowed to be supplied to the output stage and a fourth state in which the reference voltage is blocked from being supplied to the output stage; and A voltage regulation stage is configured to set a target voltage across the input stage after the second switching stage is switched from the third state to the fourth state and before the first switching stage is switched from the second state to the first state.

10. The system of claim 9, wherein the voltage regulation stage of each switching converter comprises: Inductor-capacitor LC stage; a third switching stage configured to switch between a fifth state in which the target voltage is allowed to be set across the input stage through the LC stage and a sixth state in which the target voltage is prevented from being set across the input stage; and The control module is configured as follows: When the first switching stage is in the second state, when the second switching stage is switched from the third state to the fourth state, switching the third switching stage from the sixth state to the fifth state; switching the third switching stage from the fifth state back to the sixth state when the target voltage across the input stage has been set; and When the third switching stage is switched from the fifth state back to the sixth state in a case where the second switching stage is in the fourth state, the first switching stage is switched from the second state to the first state.

11. The system according to claim 10, wherein: For each switching converter, when the third switching stage is in the fifth state, the LC stage is connected in parallel with the input stage.

12. The system of claim 10, each switching converter further comprising at least one limiting stage for limiting oscillations across the LC stage.

13. The system of claim 12, wherein at least one limiting stage of each switching converter comprises a diode element across the first switching stage and the third switching stage for limiting positive oscillations across the LC stage.

14. The system of claim 13, wherein the at least one limiting stage of each switching converter further comprises: A fourth switching stage across the LC stage is provided for limiting negative oscillations across the LC stage.

15. The system according to claim 10, wherein: For each switching converter, when the third switching stage is in the fifth state, the LC stage is connected in parallel with the output stage.

16. The system of claim 9, wherein the switching converter is a zeta converter.

17. A method for converting a DC input voltage to a DC output voltage in a switching converter, wherein the switching converter comprises: An input stage, configured to receive the input voltage; an output stage, for providing the output voltage; a capacitive coupling stage for coupling the input stage and the output stage to each other; a first switching stage configured to switch between a first state in which the input voltage is allowed to be supplied to the input stage and a second state in which the input voltage is blocked from being supplied to the input stage; a second switching stage configured to switch between a third state in which a reference voltage is allowed to be supplied to the output stage and a fourth state in which the reference voltage is prevented from being supplied to the output stage; The method comprises: switching the second switching stage from the third state to the fourth state; setting a target voltage across the input stage after switching the second switching stage from the third state to the fourth state; and After setting the target voltage across the input stage, the first switching stage is switched from the second state to the first state.

18. The method of claim 17, wherein the switching converter further comprises: Inductor-capacitor LC stage; a third switching stage configured to switch between a fifth state in which the target voltage is allowed to be set across the input stage through the LC stage and a sixth state in which the target voltage is prevented from being set across the input stage; and The method further comprises: When the first switching stage is in the second state, when the second switching stage is switched from the third state to the fourth state, switching the third switching stage from the sixth state to the fifth state; switching the third switching stage from the fifth state back to the sixth state when the target voltage across the input stage has been set; and When the second switching stage is in the fourth state, when the third switching stage switches from the fifth state back to the sixth state, the first switching stage is switched from the second state to the first state.

19. The method according to claim 18, further comprising: When the third switching stage is in the fifth state, the LC stage is connected in parallel to the input stage.

20. The method of claim 18, further comprising: Oscillations across the LC stage are limited by at least one limiting stage.

21. The method according to claim 20, further comprising: Positive oscillations across the LC stage are limited by diode elements across the first and third switching stages.

22. The method according to claim 21, further comprising: Negative oscillations across the LC stage are limited by a fourth switching stage across the LC stage.

23. The method of claim 18, further comprising: When the third switching stage is in the fifth state, the LC stage is connected in parallel to the output stage.

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