Switching circuit, charging circuit, and charging system

Abstract

The invention provides a switching circuit, a charging circuit and a charging system, the switching circuit comprises a first switch, a second switch and a third switch, and the first switch and the second switch are connected in series; the control ends of the first switch, the second switch and the third switch are used for accessing control signals; one end of the third switch is electrically connected to a first node between the first switch and the second switch, and the control ends of the first switch and the second switch are electrically connected with the other end of the third switch; wherein the switching state of the first switch and the switching state of the second switch are opposite to the switching state of the third switch, and when the third switch is closed, at least part of charges flow to the control ends of the first switch and the second switch through the third switch, so that the switching-off speed of the first switch and the second switch is increased. The switching-off speed of the first switch and the second switch can be increased, and finally the purposes of reducing the switching loss of the first switch and the second switch and preventing the first switch and the second switch from being damaged are achieved.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a switching circuit, a charging circuit and a charging system. Background Art

[0002] At present, with the widespread application of lithium batteries in various devices, there are more and more charging solutions for lithium batteries. The existing battery module charging circuit mainly uses MOS tubes for charging control. Taking NMOS tubes as an example, when the NMOS tube receives a high-level signal, the NMOS tube is turned on so that the battery module is electrically connected to the power supply and charged; when the NMOS tube receives a low-level signal, the NMOS tube is turned off to stop charging the battery module. However, when the NMOS tube is turned off, it is necessary to wait until the gate metal plate of the NMOS tube and the metal plate charge on the substrate side are completely discharged before it can be completely turned off, which makes the NMOS tube unable to turn off quickly, thereby increasing the switching loss of the NMOS tube, and ultimately causing the NMOS tube to be easily damaged in the power circuit. Summary of the invention

[0003] The present application provides a switch circuit, a charging circuit and a charging system, aiming to solve the technical problem that the switch in the current power circuit cannot be turned off quickly and causes damage to the switch.

[0004] In a first aspect, the present application provides a switch circuit, comprising:

[0005] A first switch, a second switch and a third switch, wherein the first switch is connected in series with the second switch;

[0006] The control ends of the first switch, the second switch and the third switch are used to receive control signals;

[0007] One end of the third switch is electrically connected to a first node between the first switch and the second switch, and the control ends of the first switch and the second switch are electrically connected to the other end of the third switch;

[0008] The switching states of the first switch and the second switch are opposite to the switching state of the third switch, and when the third switch is closed, at least part of the charge flows to the control ends of the first switch and the second switch through the third switch to accelerate the disconnection speed of the first switch and the second switch.

[0009] In some embodiments, opening speeds of the first switch and the second switch are lower than closing speed of the third switch.

[0010] In some embodiments, the first switch has a first parasitic diode and the second switch has a second parasitic diode;

[0011] The first parasitic diode is connected in parallel with the first switch, the second parasitic diode is connected in parallel with the second switch, and the conduction directions of the first parasitic diode and the second parasitic diode are opposite.

[0012] In some embodiments, the first switch includes a first MOS transistor, and the second switch includes a second MOS transistor;

[0013] The first end of the first MOS tube is electrically connected to the first end of the second MOS tube, the control ends of the first MOS tube and the second MOS tube are electrically connected to the first end of the third switch, and the first ends of the first MOS tube and the second NMOS tube are electrically connected to the second end of the third switch.

[0014] In some embodiments, the third switch includes a first transistor;

[0015] The control ends of the first MOS tube and the second MOS tube are electrically connected to the first end of the first triode, the first ends of the first MOS tube and the second MOS tube are electrically connected to the second end of the first triode, and the control end of the first triode is used to receive a control signal.

[0016] In a second aspect, the present application provides a charging circuit, comprising:

[0017] The switch circuit as described in the first aspect;

[0018] A first secondary winding unit, the first secondary winding unit is used for outputting a charging voltage;

[0019] The input end of the first switch of the switch circuit is electrically connected to the output end of the first secondary winding unit, and the output end of the second switch of the switch circuit is electrically connected to the battery module.

[0020] In some embodiments, the charging circuit further includes a second secondary winding unit, and the second secondary winding unit is used to output a working voltage;

[0021] The control ends of the first switch, the second switch and the third switch are electrically connected to the output end of the second secondary winding unit.

[0022] In some embodiments, the charging circuit further includes a switch control module;

[0023] The input end of the switch control module is electrically connected to the output end of the second secondary winding unit, the output end of the switch control module is electrically connected to the control end of the switch circuit, and the switch control module is used to control the second secondary winding unit to provide a control signal to the switch circuit.

[0024] In some embodiments, the switch control module includes a photocoupler;

[0025] The collector of the photocoupler is electrically connected to the second secondary winding unit, and the emitter of the photocoupler is electrically connected to the switch circuit;

[0026] The anode of the photocoupler is used to receive the control voltage signal, and the cathode terminal of the photocoupler is used to be grounded.

[0027] In some embodiments, the first secondary winding unit includes a first secondary winding, and the second secondary winding unit includes a second secondary winding;

[0028] The number of turns of the first secondary winding is greater than the number of turns of the second secondary winding.

[0029] In a third aspect, the present application provides a system, characterized in that it includes a charging circuit as described in the first aspect.

[0030] In the present application, one end of the third switch is electrically connected to the first node between the first switch and the second switch, and the other end of the third switch is electrically connected to the control ends of the first switch and the second switch, and the switching state of the first switch and the second switch is opposite to the switching state of the third switch. When the third switch is closed, the first switch and the second switch are in the disconnection process, and at least part of the charge can flow to the control ends of the first switch and the second switch through the third switch, so that the disconnection speed of the first switch and the second switch can be accelerated, and finally the switching loss of the first switch and the second switch is reduced, and the first switch and the second switch are prevented from being damaged. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0032] Figure 1 is a circuit diagram of a switch circuit provided in an embodiment of the present application;

[0033] Figure 2 is a state schematic diagram of a switch circuit provided in an embodiment of the present application;

[0034] Figure 3 is a circuit diagram of a switch circuit provided in an embodiment of the present application;

[0035] Figure 4 is another circuit diagram of the switch circuit provided in the embodiment of the present application;

[0036] Figure 5 It is a module schematic diagram of a charging circuit provided in an embodiment of the present application;

[0037] Figure 6is another module schematic diagram of a charging circuit provided in an embodiment of the present application;

[0038] Figure 7 is another module schematic diagram of a charging circuit provided in an embodiment of the present application;

[0039] Figure 8 is a circuit diagram of a charging circuit provided in an embodiment of the present application;

[0040] Fig. 9 is another circuit schematic diagram of a charging circuit provided in an embodiment of the present application;

[0041] Fig.10 It is a module schematic diagram of the charging system provided in an embodiment of the present application.

[0042] Among them, 10 is a first secondary winding unit, 20 is a second secondary winding unit, 30 is a switch circuit, 40 is a switch control module, 50 is a battery module, and 60 is a pre-charging switch module;

[0043] A first switch S1, a second switch S2, a third switch S3, a first node M1, a first parasitic diode Q1, a second parasitic diode Q2, and a first transistor Q203;

[0044] Charging voltage VBUS, control signal Vc, first MOS transistor Q201, second MOS transistor Q202, photocoupler U203, first secondary winding WD1, second secondary winding WD2, first resistor R201, first capacitor C201, second resistor R206, second capacitor C224, first transistor Q205, second transistor Q206;

[0045] PFC circuit 100 , transformer 200 , and charging control circuit 300 . DETAILED DESCRIPTION

[0046] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0047] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0048] In this application, the word "exemplary" is used to mean "serving as an example, illustration, or illustration." Any embodiment described in this application as "exemplary" is not necessarily to be construed as being preferred or advantageous over other embodiments. The following description is given to enable any person skilled in the art to implement and use the invention. In the following description, details are listed for the purpose of explanation. It should be understood that a person of ordinary skill in the art can recognize that the invention can be implemented without using these specific details. In other instances, well-known structures and processes are not elaborated in detail to avoid obscuring the description of the invention with unnecessary details. Therefore, the present invention is not intended to be limited to the embodiments shown, but is consistent with the widest scope consistent with the principles and features disclosed in this application.

[0049] The embodiments of the present application provide a switch circuit, a charging circuit 300 and a charging system, which are described in detail below.

[0050] First, see Figure 1 as well as Figure 2 , Figure 1 A circuit diagram of a switch circuit in an embodiment of the present application is shown. Figure 2 A working schematic diagram of a switch circuit in an embodiment of the present application is shown, wherein the switch circuit includes:

[0051] A first switch S1, a second switch S2 and a third switch S3, wherein the first switch S1 and the second switch S2 are connected in series;

[0052] The control ends of the first switch S1, the second switch S2 and the third switch S3 are used to receive control signals;

[0053] One end of the third switch S3 is electrically connected to the first node M1 between the first switch S1 and the second switch S2, and the control ends of the first switch S1 and the second switch S2 are electrically connected to the other end of the third switch S3;

[0054] The switching states of the first switch S1 and the second switch S2 are opposite to the switching state of the third switch S3, and when the third switch S3 is closed, at least part of the charge flows to the control ends of the first switch S1 and the second switch S2 through the third switch S3 to accelerate the disconnection speed of the first switch S1 and the second switch S2.

[0055] Specifically, the first switch S1 and the second switch S2 have a capacitor structure. When the plate of the capacitor of the first switch S1 or the second switch S2 is energized, the capacitor accumulates charges so that the charges (such as holes or electrons) between the capacitors move, thereby turning on the first switch S1 and the second switch S2. For example, taking the first switch S1 and the second switch S2 as NMOS tubes, the control ends of the first switch S1 and the second switch S2 are the gates of the NMOS tubes. After the gate metal plate and the substrate side metal plate of the NMOS tube are charged, an electric field is formed between the gate metal plate and the substrate side metal plate to repel holes and attract electrons to move to the N channel, thereby turning on the NMOS tube; conversely, when the gate metal plate of the NMOS tube receives a low-level signal, the gate metal plate and the substrate side metal plate cannot form an electric field so that the electrons move to the N channel, thereby turning off the NMOS tube. It can be understood that the first switch S1 and the second switch S2 can also be PMOS tubes or IGBT tubes.

[0056] The third switch S3 can accelerate the charging or discharging process of the charge of the capacitor structure of the first switch S1 and the second switch S2 when the first switch S1 and the second switch S2 are turned off, so that the first switch S1 and the second switch S2 are quickly turned off. For example, taking the first switch S1 and the second switch S2 as NMOS tubes as an example, after the third switch S3 is turned on, the negative charge of the metal plate on the substrate side of the NMOS tube can be transferred to the gate metal plate of the NMOS tube through the third switch S3, so that the positive charge on the gate metal plate of the NMOS tube is quickly consumed, thereby quickly reducing the gate voltage of the NMOS tube and causing the NMOS tube to be quickly turned off.

[0057] It can be understood that when the first switch S1 and the second switch S2 are PMOS tubes, the third switch S3 can transfer the positive charge of the metal plate on the substrate side of the PMOS tube to the gate metal plate of the PMOS tube through the third switch S3, so that the negative charge on the gate metal plate of the PMOS tube is quickly consumed, thereby quickly turning off the PMOS tube.

[0058] Exemplarily, the third switch S3 may be a transistor with a switching function such as a MOS tube, an IGBT tube or a triode.

[0059] It should be noted that the switch state of the first switch S1 and the second switch S2 is opposite to the switch state of the third switch S3. For example, when the first switch S1 and the second switch S2 are turned off or in the process of being turned off, the third switch S3 is in the on state; when the first switch S1 and the second switch S2 are turned on or in the process of being turned on, the third switch S3 is in the off state. In some embodiments of the present application, the first switch S1 and the second switch S2 are turned on by a high-level signal, and the third switch S3 is turned on by a low-level signal. For example, the first switch S1 and the second switch S2 are NMOS tubes, and the third switch S3 is a PMOS tube. When the control signal connected to the control end of the first switch S1, the second switch S2 and the third switch S3 is a high-level signal, the NMOS tube is turned on and the PMOS tube is turned off. In some embodiments of the present application, the first switch S1 and the second switch S2 are turned on by a low-level signal, and the third switch S3 is turned on by a high-level signal. For example, the first switch S1 and the second switch S2 are PMOS tubes, and the third switch S3 is an NMOS tube. When the control signal connected to the control end of the first switch S1, the second switch S2 and the third switch S3 is a low-level signal, the PMOS tube is turned on and the NMOS tube is turned off.

[0060] In the embodiment of the present application, one end of the third switch S3 is electrically connected to the first node M1 between the first switch S1 and the second switch S2, and the other end of the third switch S3 is electrically connected to the control end of the first switch S1 and the second switch S2, and the switching state of the first switch S1 and the second switch S2 is opposite to the switching state of the third switch S3. When the third switch S3 is closed, the first switch S1 and the second switch S2 are in the disconnection process, and at least part of the charge can flow to the control end of the first switch S1 and the second switch S2 through the third switch S3, so that the disconnection speed of the first switch S1 and the second switch S2 can be accelerated, and finally the switching loss of the first switch S1 and the second switch S2 is reduced, and the first switch S1 and the second switch S2 are prevented from being damaged.

[0061] In some embodiments of the present application, the disconnection speed of the first switch S1 and the second switch S2 is less than the closing speed of the third switch S3. For example, taking the case where the first switch S1 and the second switch S2 are turned on by a high-level signal, and the third switch S3 is turned on by a low-level signal, when the control signal is converted from a high level to a low level, since the closing speed of the third switch S3 is faster, the third switch S3 is converted to a conducting (closed) state before the first switch S1 and the second switch S2 are completely disconnected. Therefore, during the disconnection process of the first switch S1 and the second switch S2, the third switch S3 can be used to transfer charges to the control terminals of the first switch S1 and the second switch S2, thereby accelerating the disconnection speed of the first switch S1 and the second switch S2.

[0062] In some embodiments of the present application, see Figure 3 , Figure 3 A circuit diagram of a switch circuit in an embodiment of the present application is shown, wherein the first switch S1 has a first parasitic diode Q1, and the second switch S2 has a second parasitic diode Q2; the first parasitic diode Q1 is connected in parallel with the first switch S1, and the second parasitic diode Q2 is connected in parallel with the second switch S2, and the first parasitic diode Q1 and the second parasitic diode Q2 are turned on in opposite directions. Specifically, when the first switch S1 and the second switch S2 are disconnected, the two parasitic diodes can block currents in two directions, thereby preventing current from flowing back into the charging circuit 300, thereby preventing current from flowing back and damaging the circuit in the charging system.

[0063] In some embodiments of the present application, see Figure 3 The first switch S1 includes a first MOS transistor Q201, and the second switch S2 includes a second MOS transistor Q202; a first end of the first MOS transistor Q201 is electrically connected to a first end of the second MOS transistor Q202, a control end of the first MOS transistor Q201 and a control end of the second MOS transistor Q202 are electrically connected to a first end of the third switch S3, and a first end of the first MOS transistor Q201 and a first end of the second MOS transistor Q202 are electrically connected to a second end of the third switch S3.

[0064] It should be noted that the first electrode / first end of each transistor used in the embodiments of the present application is one of the source or the drain, the second electrode / second end of each transistor is the other of the source or the drain, and the control end of each transistor refers to the gate / base. Since the source and drain of the transistor can be symmetrical in structure, the source and drain can be structurally indistinguishable, that is, the first electrode / first end and the second electrode / second end of the transistor in the embodiments of the present application can be structurally indistinguishable.

[0065] Exemplarily, when the transistor is a P-type transistor, the first electrode / first end of the transistor is the source, and the second electrode / second end is the drain; exemplary, when the transistor is an N-type transistor, the first electrode / first end of the transistor is the drain, and the second electrode / second end is the source.

[0066] Exemplarily, taking the first MOS tube Q201 and the second MOS tube Q202 as NMOS tubes, the source of the first NMOS tube Q201 is electrically connected to the source of the second NMOS tube Q202; the drain of the first NMOS tube Q201 is electrically connected to the output end of the first secondary winding unit 10, and the drain of the second NMOS tube Q202 is electrically connected to the output end of the charging control circuit 300. Since the NMOS tube has a unidirectional conduction characteristic with the source pointing to the gate, and the source of the first NMOS tube Q201 is electrically connected to the source of the second NMOS tube Q202, the first NMOS tube Q201 and the second NMOS tube Q202 respectively have two parasitic diodes with opposite conduction directions. When the first NMOS tube Q201 and the second NMOS tube Q202 are working, the two parasitic diodes can block currents in two directions, thereby preventing current from flowing back to the charging control circuit 300, thereby avoiding current backflow and damaging the circuit in the charging control system.

[0067] It can be understood that the first MOS transistor Q201 and the second MOS transistor Q202 can also be PMOS transistors, and the sources of the two PMOS transistors are connected to each other, so as to form a switch circuit 30 with two parasitic diodes facing each other.

[0068] In some embodiments of the present application, for example, in an embodiment in which the opening speed of the first switch S1 and the second switch S2 is less than the closing speed of the third switch S3, continue to refer to Figure 4 , Figure 4 Another circuit schematic diagram of the switch circuit in an embodiment of the present application is shown, wherein the third switch S3 includes a first triode Q203; the control ends of the first MOS transistor Q201 and the second MOS transistor Q202 are electrically connected to the first end of the first triode Q203, the first ends of the first MOS transistor Q201 and the second MOS transistor Q202 are electrically connected to the second end of the first triode Q203, and the control end of the first triode Q203 is used to receive a control signal.

[0069] It should be noted that, taking the case where the first MOS tube is a first NMOS tube, the second MOS tube is a second NMOS tube, and the first triode is a first PNP triode as an example, when the control signals connected to the control ends of the first MOS tube, the second MOS tube, and the first triode are respectively high-level signals, the first MOS tube Q201 and the second MOS tube Q202 are turned on, and the first triode Q203 is turned off; conversely, when the control signals connected to the control ends of the first switch S1, the second switch S2, and the third switch S3 are low-level signals, the first MOS tube Q201 and the second MOS tube Q202 are turned off, and the first triode Q203 is turned on.

[0070] At the same time, since the closing speed of the first triode Q203 is greater than the disconnection speeds of the first MOS tube Q201 and the second MOS tube Q202, at the closing moment of the first triode Q203, the first MOS tube Q201 and the second MOS tube Q202 are still in the disconnection process. At this time, the negative charges of the substrate metal plates of the first MOS tube Q201 and the second MOS tube Q202 can flow to the gate metal plates of the first MOS tube Q201 and the second MOS tube Q202 through the first triode Q203, thereby accelerating the disconnection speed of the first MOS tube Q201 and the second MOS tube Q202.

[0071] It is worth noting that the above contents about the switch are intended to clearly illustrate the implementation verification process of the present application. Under the guidance of the present application, those skilled in the art can also make equivalent modified designs. For example, the first switch S1 can also include multiple NMOS tubes connected in series or in parallel.

[0072] Furthermore, in order to better implement the switch circuit 30 in the embodiment of the present application, based on the switch circuit 30, the present application also provides a charging circuit 300. Figure 5 , Figure 5 A module schematic diagram of a charging circuit 300 in an embodiment of the present application is shown, wherein the charging circuit 300 includes:

[0073] The switch circuit 30 as described in any of the above embodiments;

[0074] A first secondary winding unit 10, the first secondary winding unit 10 is used to output a charging voltage VBUS;

[0075] The input end of the first switch S1 of the switch circuit 30 is electrically connected to the output end of the first secondary winding unit 10 , and the output end of the second switch S2 of the switch circuit 30 is electrically connected to the battery module 50 .

[0076] In the charging circuit 300 provided in the present application, the first secondary winding unit 10 is connected to the first secondary winding WD1 of the transformer, and the first secondary winding WD1 is coupled to the primary winding of the transformer. An induced electromotive force is generated through the first secondary winding WD1 to output the electric energy to be converted. After passing through the first secondary winding unit 10, the electric energy to be converted provides a charging voltage VBUS to the battery module 50, and then the switching circuit 30 can be used to control whether the battery module is charged.

[0077] The battery module 50, as a charged object or a discharge object that releases electric energy, is an energy storage and energy release component in the charge and discharge control system, so that the charge and discharge control system can complete the normal energy storage process and energy release process. In some embodiments of the present application, the battery module 50 can be composed of single cells, such as lithium manganese oxide batteries, lithium cobalt oxide batteries, lithium iron phosphate batteries, ternary lithium batteries, lead-acid batteries, nickel-cadmium batteries, nickel-iron batteries, or nickel-hydride batteries.

[0078] In some other embodiments of the present application, the battery module 50 may be composed of a plurality of single cells. For example, a plurality of single cells are connected in series to form a battery module or in parallel to form a battery module or a battery module formed by series-parallel connection.

[0079] In the charging circuit 300 provided in the present application, when the third switch S3 is closed, the first switch S1 and the second switch S2 are in the process of being disconnected, and at least part of the charge can flow to the control ends of the first switch S1 and the second switch S2 through the third switch S3, thereby accelerating the disconnection speed of the first switch S1 and the second switch S2. Ultimately, when charging of the battery module 50 is stopped, the switching loss of the first switch S1 and the second switch S2 can be reduced, and damage to the first switch S1 and the second switch S2 can be prevented.

[0080] In some embodiments of the present application, see Figure 6 , Figure 6 Another module schematic diagram of the charging circuit 300 in the embodiment of the present application is shown, wherein the charging circuit 300 also includes a second secondary winding unit 20, which is used to output a control signal Vc; the control ends of the first switch S1, the second switch S2 and the third switch S3 are electrically connected to the output end of the second secondary winding unit.

[0081] It should be noted that the second secondary winding unit 20 is connected to the second secondary winding WD2 of the transformer, and the second secondary winding WD2 is also coupled to the primary winding of the transformer 200. An induced electromotive force is generated by the second secondary winding WD2, and then the induced electromotive force generated by the second secondary winding WD2 is converted into an operating voltage of the control circuit through the second secondary winding unit 20, so that the control circuit 40 can output a control signal Vc for controlling the switch circuit 30.

[0082] In some embodiments of the present application, the first secondary winding WD1 and the second secondary winding WD2 can be coupled to the primary winding of the same transformer, that is, the first secondary winding WD1 and the second secondary winding WD2 belong to the same transformer. In some other embodiments of the present application, the first secondary winding WD1 and the second secondary winding WD2 can be coupled to the primary windings of two transformers, that is, the first secondary winding WD1 and the second secondary winding WD2 belong to different transformers, and the charging power for charging the battery module 50 and the operating voltage of the control circuit are outputted through the secondary windings of the two transformers.

[0083] In the above embodiment, since the charging voltage VBUS is provided to the battery module 50 through the first secondary winding unit 10, and the control signal Vc is provided to the switch circuit 30 through the second secondary winding unit 20, the control circuit and the power transmission circuit of the charging circuit 300 each use a secondary winding, and the switch circuit 30 is driven to be turned on and off through the independent second secondary winding unit 20, so that the turning on and off of the switch circuit 30 will not be affected by the power transmission circuit, which is beneficial to improving the control accuracy of the switch circuit 30 and avoiding the phenomenon that the switch circuit 30 is affected by the power transmission circuit and causes the switch state to be unstable.

[0084] In some embodiments of the present application, see Figure 7 , Figure 7 Another module schematic diagram of the charging circuit 300 in the embodiment of the present application is shown, wherein the charging circuit 300 also includes a switch control module 40; the input end of the switch control module 40 is electrically connected to the output end of the second secondary winding unit 20, and the output end of the switch control module 40 is electrically connected to the control end of the switch circuit 30, and the switch control module 40 is used to control the second secondary winding unit 20 to provide a control signal Vc to the control end of the switch circuit 30.

[0085] Specifically, the switch control module 40 can control whether the second secondary winding unit 20 provides the control signal Vc to the control end of the charging switch circuit 30, so as to indirectly control the switch circuit 30 to be opened or closed.

[0086] In some embodiments of the present application, the switch control module 40 may include one or more switches. When any switch is disconnected, the second secondary winding unit 20 stops supplying power to the control end of the switch circuit 30, thereby disconnecting the switch circuit 30 and eventually stopping charging the battery module 50. When all switches are closed, the second secondary winding unit 20 supplies power to the control end of the switch circuit 30, thereby closing the switch circuit 30 and eventually charging the battery module 50. Exemplarily, the switch in the switch control module 40 may be a transistor with a switch function, such as a MOS tube, an IGBT tube or a triode.

[0087] As an example, see Figure 8 , Figure 8 A circuit schematic diagram of a charging circuit 300 in an embodiment of the present application is shown, wherein the switch control module includes a photocoupler U203; the collector of the photocoupler U203 is electrically connected to the second secondary winding unit 20, and the emitter of the photocoupler U203 is electrically connected to the switch circuit 30; the anode of the photocoupler U203 is used to receive the control voltage signal O / P_MOS_CTRL, and the cathode end of the photocoupler U203 is used for grounding.

[0088] It should be noted that the control voltage signal O / P_MOS_CTRL can be issued by a processing circuit or a single-chip microcomputer constituted by a chip. After the anode of the photocoupler U203 receives the control voltage signal, the photodiode of the photocoupler U203 emits light, so that the emitter and collector of the light receiver are connected. The control circuit 40 is in a closed state at this time, so the second secondary winding unit 20 provides a voltage to the control end of the switch circuit 30, so that the switch circuit 30 is turned on. At the same time, since the photocoupler U203 can isolate the control voltage signal O / P_MOS_CTRL issued by the chip from the voltage signal of the working voltage Vc output by the second secondary winding, the control voltage signal O / P_MOS_CTRL is isolated from the voltage signal of the working voltage Vc. In combination with the embodiment in which the control circuit and the power transmission circuit of the charging control circuit 300 of the present application are each isolated by a secondary winding, the control voltage signal O / P_MOS_CTRL can be effectively prevented from being interfered by other voltage signals, which is conducive to further improving the control accuracy of the switch circuit 30.

[0089] It is understandable that the switch control module 40 may also use transistors with switch functions such as MOS tubes, IGBT tubes or triodes to achieve switch control.

[0090] In some embodiments of the present application, see Figure 8 , wherein the number of turns of the first secondary winding WD1 is greater than the number of turns of the second secondary winding WD2. Specifically, since the number of turns of the first secondary winding WD1 is greater than the number of turns of the second secondary winding WD2, the induced electromotive force of the first secondary winding WD1 will be greater than the induced electromotive force of the second secondary winding WD2, which can reduce the energy consumption of the second secondary winding WD2, the second secondary winding unit 20 and the control circuit 40, and improve the charging efficiency of the battery module 50.

[0091] In some embodiments of the present application, see Figure 8, wherein the first secondary winding unit 10 includes a first unidirectional diode D201, a first resistor R201 and a first capacitor C201; the first end of the first unidirectional diode D201 is electrically connected to the first end of the first secondary winding WD1 of the transformer 200, the second end of the first unidirectional diode D201 is electrically connected to the first end of the first resistor R201, and the second end of the first resistor R201 is electrically connected to the input end of the switching circuit 30; the first end of the first capacitor C201 is electrically connected to the second end of the first resistor R201, and the second end of the first capacitor C201 is electrically connected to the second end of the first secondary winding WD1.

[0092] Specifically, the first unidirectional diode D201 can perform half-wave rectification on the AC signal input by the first secondary winding WD1 of the transformer 200, so as to convert the AC signal into a DC signal and provide it to the battery module 50 for charging, while the first resistor R201 and the first capacitor C201 form a resistor-capacitor circuit (RC shaping circuit), which is beneficial to eliminate noise in the DC signal, thereby avoiding the phenomenon of sharp pulse voltage in the charging voltage VBUS received by the battery module 50.

[0093] It can be understood that the first secondary winding unit 10 can also use a bridge rectifier circuit or a full-wave rectifier circuit to replace the first unidirectional diode D201 to convert the AC signal into a DC signal; or the first secondary winding unit 10 can also use a MOS tube rectifier circuit to replace the first unidirectional diode D201 to convert the AC signal into a DC signal.

[0094] In some embodiments of the present application, see Fig. 9 , Fig. 9 Another circuit schematic diagram of the charging circuit 300 in an embodiment of the present application is shown, wherein the first secondary winding unit 10 includes a first unidirectional diode D201, a first resistor R201 and a first capacitor C201; the first end of the first unidirectional diode D201 is electrically connected to the first end of the first secondary winding of the transformer, and the second end of the first unidirectional diode D201 is electrically connected to the first end of the first capacitor C201; the first end of the first resistor R201 is electrically connected to the first end of the first unidirectional diode D201, and the second end of the first resistor R201 is electrically connected to the second end of the first capacitor C201.

[0095] Similarly, the first unidirectional diode D201 can perform half-wave rectification on the AC signal input by the first secondary winding WD1 of the transformer 200. At the same time, when the AC signal input by the first secondary winding WD1 is pulled high, the first secondary winding WD1 charges the first capacitor C201 through the first resistor R201. When the AC signal input by the first secondary winding WD1 is pulled low, the first secondary winding WD1 discharges the first capacitor C201 through the first resistor R201, which is beneficial to filtering the AC signal input by the first secondary winding WD1, converting the AC signal input by the first secondary winding WD1 and obtaining a DC signal with a smooth waveform, so as to achieve the purpose of DC charging of the battery module 50.

[0096] It can be understood that the first unidirectional diode D201 can be a single diode. The first unidirectional diode D201 can also be as Fig. 9 The configuration shown is to have multiple unidirectional diodes connected in parallel, which can withstand a larger current and act as a shunt while achieving rectification; alternatively, the first resistor R201 can also be configured as multiple resistors connected in parallel (for example, resistors R201, R202, and R203) to provide a greater number of branches to charge / discharge the first capacitor C201.

[0097] In some embodiments of the present application, see Figure 8 , wherein the second secondary winding unit 20 includes a second unidirectional diode D202, a second resistor R206 and a second capacitor C224; the first end of the second unidirectional diode D202 is electrically connected to the first end of the second secondary winding WD2 of the transformer 200, the second end of the second unidirectional diode D02 is electrically connected to the first end of the second resistor R206, and the second end of the second resistor R206 is electrically connected to the input end of the control circuit 40; the first end of the second capacitor C224 is electrically connected to the second end of the second resistor R206, and the second end of the second capacitor C224 is electrically connected to the second end of the second secondary winding WD2. Similarly, the second unidirectional diode D202 can perform half-wave rectification on the AC signal input by the second secondary winding WD2 of the transformer 200, so as to convert the AC signal into a DC signal and provide it to the control circuit 40 for switching control, while the second resistor R206 and the second capacitor C224 form a resistor-capacitor circuit (RC shaping circuit), which is beneficial to eliminating noise in the DC signal and avoiding the instability of the working voltage Vc connected to the control end of the switching circuit 30, which leads to the unstable switching state of the switching circuit 30.

[0098] It can be understood that the second secondary winding unit 20 can also use a bridge rectifier circuit or a full-wave rectifier circuit to replace the second unidirectional diode D202 to convert the AC signal into a DC signal.

[0099] In some embodiments of the present application, see Figure 8 , wherein the charging control circuit 300 also includes a pre-charging switch circuit 60; one end of the pre-charging switch circuit 60 is electrically connected to the first secondary winding unit 10, and the other end is electrically connected to the output end of the charging control circuit 300, and the pre-charging switch circuit 60 is connected in parallel with the switch circuit 30; during the operation of the charging control circuit 300, the switching state of the pre-charging switch circuit 60 is mutually exclusive with the switching state of the switch circuit 30.

[0100] Specifically, before the switch circuit 30 is closed, the pre-charge switch circuit 60 is turned on so that the charging voltage VBUS is electrically connected to the battery module 50, so as to pre-charge the battery module 50 to activate the battery module 50, and the voltage signal of the battery module 50 can be obtained through the BAT1+ interface to facilitate the determination of whether the voltage of the battery module 50 meets the requirements, and to avoid the phenomenon that the voltage of the battery module 50 is too high or too low. After determining that the voltage of the battery module 50 is qualified and activating the battery module 50, the pre-charge switch circuit 60 can be disconnected, and the switch circuit 30 can be closed to charge the battery module 50 using the charging voltage VBUS.

[0101] In some embodiments of the present application, see Figure 8 The pre-charging switch circuit 60 includes a first switch tube Q205; a first end of the first switch tube Q205 is electrically connected to the first secondary winding unit 10, and a second end of the first switch tube Q205 is electrically connected to the battery module 50. Specifically, when the control end of the first switch tube Q205 receives a voltage signal to close the first switch tube Q205, the first secondary winding unit 10 charges the battery module 50 through the first switch tube Q205, so as to judge whether the voltage of the battery module 50 meets the requirements through the BAT1+ interface.

[0102] As an example, the first switch tube Q205 is a triode, the emitter of the first switch tube Q205 is electrically connected to the first secondary winding unit 10, the collector of the first switch tube Q205 is electrically connected to the battery module 50, and the emitter of the first switch tube Q205 is electrically connected to the base of the first switch tube Q205. Specifically, when the base of the first switch tube Q205 is connected to the signal, the emitter and collector of the first switch tube Q205 are turned on, so that the charging voltage VBUS is connected to the battery module 50 and the battery module 50 is pre-charged. Detection.

[0103] Further, in some embodiments of the present application, continue to refer to Figure 8The pre-charge switch circuit 60 further includes a second switch tube Q206; the second end of the second switch tube Q206 is electrically connected to the control end of the first switch tube Q205, the first end of the second switch tube Q206 is electrically connected to the control end of the second switch tube Q206, and the control end of the second switch tube Q206 is used to access the pre-charge control signal. Specifically, when the control end of the second switch tube Q206 receives the pre-charge control signal (for example, the BAT-ON signal sent by the chip), the first end of the second switch tube Q206 is connected to the second end, so that the pre-charge control signal is transmitted to the control end of the first switch tube Q205, so that the second switch tube Q206 is used to indirectly control the switch state of the first switch tube Q205.

[0104] As an example, the second switch tube Q206 is a triode, the collector of the second switch tube Q206 is electrically connected to the base of the first switch tube Q205, the emitter of the second switch tube Q206 is electrically connected to the base of the second switch tube Q206, and the base of the second switch tube Q206 is used to access the pre-charge control signal. Specifically, since the collector of the second switch tube Q206 is electrically connected to the base of the first switch tube Q205, after the base of the second switch tube Q206 receives a signal (such as a BAT-ON signal sent by the chip), the collector and emitter of the second switch tube Q206 are turned on, so that the base of the first switch tube Q205 is connected to the signal and the first switch tube Q205 is turned on. In addition, the second switch tube Q206 can also separate the pre-charge control signal (such as the BAT-ON signal sent by the chip) from the charging voltage VBUS to avoid the phenomenon that the pre-charge control signal is interfered by the charging voltage VBUS.

[0105] It can be understood that the pre-charging switch circuit 60 can also use MOS tubes or IGBT tubes to realize the switching function; or, a third transistor or even a larger number of transistors can be set, the BAT-ON signal emitted by the chip is connected to the base of the third transistor, and the collector of the third transistor is electrically connected to the base of the second switch tube Q206, so that the base of the second switch tube Q206 is controlled by the third transistor.

[0106] It is worth noting that the above contents about the charging control circuit 300 are intended to clearly illustrate the implementation verification process of the present application. Under the guidance of those skilled in the art, equivalent modified designs can also be made. For example, see Figure 8 , a capacitor C228 and a resistor R269 may be connected in parallel between the anode and cathode of the photocoupler U203, and a resistor R208 may be connected in series with the anode of the photocoupler U203 to shape the connected control voltage signal; for another example, a resistor R218, R219, R2220 or R221 may be provided as a resistor used for voltage reduction; for another example, Fig. 9As shown, parallel capacitors EC202 and EC203 may also be provided to filter the signal output by the first secondary winding unit 10 .

[0107] Further, in order to better implement the charging circuit 300 in the embodiment of the present application, based on the charging circuit 300, the present application also provides a charging system, see Fig.10 , Fig.10 A module schematic diagram of a charging system in an embodiment of the present application is shown, and the charging system includes a charging control system including a PFC circuit 100, a transformer 200 and a charging circuit 300 described in any of the above embodiments, which are electrically connected in sequence. The charging system can be applied to electric vehicles, hybrid vehicles, electric bicycles, electric pedals, electric skateboards and other electrically driven mobile devices.

[0108] Specifically, the PFC circuit 100 (Power Factor Correction circuit) can improve the circuit power factor, thereby reducing the circuit power loss input to the transformer 200 and improving the circuit transmission efficiency of the charging control system. Exemplarily, the PFC circuit 100 can be a boost PFC circuit 100 or a buck PFC circuit 100. The PFC circuit 100 can be an active PFC circuit or a passive PFC circuit.

[0109] The transformer 200 can convert the voltage input by the PFC circuit 100 into the voltage required by the corresponding device to adapt to the corresponding electrical equipment (such as a rechargeable battery pack, an electric car, an electric truck or an electric bicycle, etc.). For example, the first secondary winding unit 10 connected to the first secondary winding WD1 of the transformer 200 can provide the charging power required by the battery module 50. For another example, the second secondary winding unit 20 connected to the second secondary winding WD2 of the transformer 200 can provide the working voltage of the control circuit, and then output a control signal to the switch circuit 30. Exemplarily, the transformer 200 can be a core transformer 200, a shell transformer 200, an amorphous alloy transformer, etc. The transformer 200 can also be other types of transformers. The transformer 200 can be an isolation transformer or a non-isolation transformer. This is just an example, and there is no excessive restriction on the type of transformer.

[0110] It can be understood that the charging control system may also include other circuit modules, such as an output filter circuit, a lightning protection circuit, an overcurrent and overvoltage protection circuit, a processing circuit and / or a battery module detection circuit, a feedback output control circuit, a flyback control circuit, a transformer primary switch control circuit, etc. For another example, a filter circuit is provided at the input end of the PFC circuit 100. The first secondary winding unit 10 includes an AC / DC conversion circuit; the AC / DC conversion circuit includes a rectifier circuit, which may be a bridge rectifier circuit, a half-wave rectifier circuit, or a full-wave rectifier circuit; the AC / DC conversion circuit includes a voltage adjustment circuit, which includes a boost circuit and / or a buck circuit. The processing circuit may be a processing circuit composed of an MCU chip, or a processing circuit composed of other processing chips. The operating voltage of the processing circuit may be provided by a DC voltage obtained by rectifying the AC power output by the third auxiliary winding of the transformer.

[0111] Since the charging system in the embodiment of the present application is provided with the charging circuit 300 of any of the above embodiments, it has all the beneficial effects of the above charging circuit 300, which will not be described in detail here.

[0112] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the detailed description of other embodiments above, and will not be repeated here.

[0113] It should be noted that in the embodiments of the present application, "connection" can be understood as electrical connection, and the electrical connection between two electrical components can be a direct or indirect electrical connection between the two electrical components. For example, the connection between A and B can be either a direct connection between A and B or an indirect electrical connection between A and B through one or more other electrical components.

[0114] The basic concepts have been described above. Obviously, for those skilled in the art, the above detailed disclosure is only for example and does not constitute a limitation of the present application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements and amendments to the present application. Such modifications, improvements and amendments are suggested in the present application, so such modifications, improvements and amendments still belong to the spirit and scope of the exemplary embodiments of the present application.

[0115] At the same time, the present application uses specific words to describe the embodiments of the present application. For example, "one embodiment", "an embodiment", and / or "some embodiments" refer to a certain feature, structure or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more in different positions in this specification does not necessarily refer to the same embodiment. In addition, some features, structures or characteristics in one or more embodiments of the present application can be appropriately combined.

[0116] Similarly, it should be noted that in order to simplify the description of the disclosure of this application and thus help understand one or more embodiments of the invention, in the above description of the embodiments of this application, multiple features are sometimes combined into one embodiment, figure or description thereof. However, this disclosure method does not mean that the features required by the object of this application are more than the features mentioned in the claims. In fact, the features of the embodiments are less than all the features of the single embodiment disclosed above.

[0117] In some embodiments, numbers describing the number of components and attributes are used. It should be understood that such numbers used in the description of the embodiments are modified by the modifiers "about", "approximately" or "substantially" in some examples. Unless otherwise specified, "about", "approximately" or "substantially" indicate that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which may change according to the required features of individual embodiments. In some embodiments, the numerical parameters should take into account the specified significant digits and adopt the general method of retaining digits. Although the numerical domains and parameters used to confirm the breadth of their range in some embodiments of the present application are approximate values, in specific embodiments, the setting of such numerical values ​​is as accurate as possible within the feasible range.

[0118] Each patent, patent application, patent application publication, and other materials, such as articles, books, specifications, publications, documents, etc., cited in this application is hereby incorporated by reference in its entirety, except for application history documents that are inconsistent with or conflicting with the content of this application, and documents that limit the broadest scope of the claims of this application (currently or later attached to this application). It should be noted that if the descriptions, definitions, and / or use of terms in the accompanying materials of this application are inconsistent or conflicting with the content described in this application, the descriptions, definitions, and / or use of terms in this application shall prevail.

[0119] The above is a detailed introduction to a switching circuit, a charging circuit and a charging system provided in the embodiments of the present application. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A switching circuit, characterized in that: The switch circuit comprises: A first switch, a second switch and a third switch, wherein the first switch is connected in series with the second switch; The control ends of the first switch, the second switch and the third switch are used to receive control signals; One end of the third switch is electrically connected to a first node between the first switch and the second switch, and the control ends of the first switch and the second switch are electrically connected to the other end of the third switch; The switching states of the first switch and the second switch are opposite to the switching state of the third switch, and when the third switch is closed, at least part of the charge flows to the control ends of the first switch and the second switch through the third switch to speed up the disconnection speed of the first switch and the second switch.

2. The switch circuit according to claim 1, characterized in that: The opening speed of the first switch and the second switch is lower than the closing speed of the third switch.

3. The switch circuit according to claim 1, characterized in that: The first switch has a first parasitic diode, and the second switch has a second parasitic diode; The first parasitic diode is connected in parallel with the first switch, the second parasitic diode is connected in parallel with the second switch, and the first parasitic diode and the second parasitic diode are conducted in opposite directions.

4. The switch circuit according to claim 1, characterized in that: The first switch includes a first MOS transistor, and the second switch includes a second MOS transistor; The first end of the first MOS tube is electrically connected to the first end of the second MOS tube, the control ends of the first MOS tube and the second MOS tube are electrically connected to the first end of the third switch, and the first ends of the first MOS tube and the second MOS tube are electrically connected to the second end of the third switch.

5. The switch circuit according to claim 4, characterized in that: The third switch includes a first transistor; The control ends of the first MOS transistor and the second MOS transistor are electrically connected to the first end of the first transistor, the first ends of the first MOS transistor and the second MOS transistor are electrically connected to the second end of the first transistor, and the control ends of the first transistor are used to receive control signals.

6. A charging circuit, characterized in that: The charging circuit comprises: The switching circuit according to any one of claims 1 to 5; A first secondary winding unit, wherein the first secondary winding unit is used to output a charging voltage; Wherein, the input end of the first switch of the switch circuit is electrically connected to the output end of the first secondary winding unit, and the output end of the second switch of the switch circuit is electrically connected to the battery module.

7. The charging circuit according to claim 6, characterized in that: The charging circuit further includes a second secondary winding unit, and the second secondary winding unit is used to provide an operating voltage; Control ends of the first switch, the second switch and the third switch are electrically connected to the output end of the second secondary winding unit.

8. The charging circuit according to claim 7, characterized in that: The charging circuit also includes a switch control module; The input end of the switch control module is electrically connected to the output end of the second secondary winding unit, the output end of the switch control module is electrically connected to the control end of the switch circuit, and the switch control module is used to provide a control signal to the switch circuit.

9. The charging circuit according to claim 8, characterized in that: The switch control module includes a photoelectric coupler; The collector of the photoelectric coupler is electrically connected to the second secondary winding unit, and the emitter of the photoelectric coupler is electrically connected to the switch circuit; The anode of the photoelectric coupler is used to receive a control voltage signal, and the cathode of the photoelectric coupler is used to be grounded.

10. A charging system, characterized in that: Comprising the charging circuit as claimed in any one of claims 6 to 9.

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