BMS and Buck-Boost converter integrated circuit and electronic equipment

Abstract

The invention relates to the technical field of lithium battery charging and discharging, and discloses a BMS and Buck-Boost converter integrated circuit and electronic equipment. An energy storage unit of the integrated circuit is electrically connected between a battery side circuit comprising a first switch tube Q3 and a charging and discharging side circuit comprising a fourth switch tube Q6; the Q3 is multiplexed as a power switch tube of the DC / DC converter and a discharge control switch tube of the BMS, and in a discharge working mode, the Q3 responds to a PWM control signal to perform switching action so as to realize step-down conversion, and meanwhile, the Q3 is used as a BMS discharge control switch to control the on-off of a discharge path of the battery unit; the Q6 is multiplexed as a power switch tube of the DC / DC converter and a charging control switch tube of the BMS, responds to a PWM control signal to carry out a switching action in a charging working mode so as to realize boost conversion, and is used as a BMS charging control switch to control the on-off of a charging path of the battery unit at the same time; by designing the function multiplexing of Q3 and Q6, the requirement that independent charging and discharging control switches Q1 and Q2 must be designed in a traditional BMS is eliminated.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium battery charging and discharging, and in particular to a BMS and Buck-Boost converter integrated circuit and electronic equipment. Background Art

[0002] Lithium-ion battery applications (including single cells or battery packs) typically require a battery management system (BMS). Its basic circuitry consists of a fuse (F1), a charge control MOSFET (MOSFET) Q1, a discharge control transistor (Q2), a current sampling resistor (R1), and a control circuit. The BMS's primary function is to ensure safe operation of the lithium-ion battery during charging and discharging, and to accurately measure the battery's SOC.

[0003] Furthermore, adding a converter can further expand the application range of lithium batteries. For example, a Buck DC / DC converter can reduce the battery voltage to the required stable DC power; a Boost DC / DC converter can increase the battery voltage to the required stable DC power.

[0004] like Figure 1 The basic circuitry of the buck-boost DC / DC converter shown in the figure consists of two filter capacitors C1 / C2, four controllable semiconductor switches Q3-Q6, an inductor L1, and a control circuit. This circuit can both charge and discharge the battery (BAT), enabling bidirectional energy flow and control in both the BMS and DC / DC stages.

[0005] However, due to the limitations of existing technology, its BMS and DC / DC converter usually adopt a separate design. The current is transmitted from one end to the other end through the above-mentioned circuit and will flow through the controllable semiconductor switch tubes Q1-Q6. The current flowing through will do work on the on-resistance of these devices, resulting in conduction loss. The more controllable semiconductor switch tubes the current flows through, the higher the power loss will be, and it will cause difficulty in circuit heat dissipation. The large amount of controllable semiconductor switch tubes used further causes technical problems such as high cost and large size, which seriously limits the application scope of lithium batteries.

[0006] Therefore, there is an urgent need for BMS and Buck-Boost converter integrated circuits and electronic devices to overcome the above-mentioned defects. Summary of the Invention

[0007] The purpose of the present invention is to provide a BMS and Buck-Boost converter integrated circuit and electronic equipment, which reduces the number of semiconductor switching devices, reduces system costs, and improves energy conversion efficiency by multiplexing the functions of switch tubes.

[0008] To achieve this object, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides a BMS and Buck-Boost converter integrated circuit, which includes a positive input terminal, a negative input terminal, a first charge and discharge terminal, a second charge and discharge terminal, a first switch tube Q3, a fourth switch tube Q6, and an energy storage unit, wherein the positive input terminal is electrically connected to the positive electrode of the battery cell, the negative input terminal is electrically connected to the negative electrode of the battery cell, the first charge and discharge terminal and the second charge and discharge terminal are electrically connected to a charger and / or a load, respectively, and the energy storage unit is electrically connected between a battery-side circuit including the first switch tube Q3 and a charge and discharge-side circuit including the fourth switch tube Q6;

[0010] The first switch tube Q3 is multiplexed as a power switch tube of the DC / DC converter and a discharge control switch tube of the BMS. In the discharge working mode, the first switch tube Q3 responds to the PWM control signal to perform switching action to achieve step-down conversion, and at the same time acts as the BMS discharge control switch to control the discharge path of the battery cell.

[0011] The fourth switch tube Q6 is multiplexed as a power switch tube of the DC / DC converter and a charging control switch tube of the BMS. In the charging working mode, the fourth switch tube Q6 responds to the PWM control signal to perform switching action to achieve boost conversion, and at the same time acts as the BMS charging control switch to control the charging path of the battery unit to be opened and closed.

[0012] Preferably, the BMS and Buck-Boost converter integrated circuit further includes a second switching tube Q4 and a third switching tube Q5, the energy storage unit includes a first inductor L1, the source of the first switching tube Q3 and the drain of the second switching tube Q4 are electrically connected to form a first switching node, the drain of the third switching tube Q5 and the source of the fourth switching tube Q6 are electrically connected to form a second switching node, and the first inductor L1 is electrically connected between the first switching node and the second switching node;

[0013] The negative input terminal is electrically connected to the second charge and discharge terminal to form a negative branch. The drain of the first switch tube Q3 is electrically connected to the positive input terminal. The source of the second switch tube Q4 is electrically connected to the negative branch. The drain of the fourth switch tube Q6 is electrically connected to the first charge and discharge terminal. The source of the third switch tube Q5 is electrically connected to the negative branch. The first charge and discharge terminal is a positive electrode, and the second charge and discharge terminal is a negative electrode.

[0014] Preferably, the energy storage unit includes a first inductor L1, the drain of the first switching tube Q3 is electrically connected to the positive input terminal, the source is electrically connected to the source of the fourth switching tube Q6, the drain of the fourth switching tube Q6 is electrically connected to the first charge and discharge terminal, the negative input terminal and the second charge and discharge terminal are electrically connected to form a negative branch, one end of the first inductor L1 is electrically connected to the connection point between the source of the first switching tube Q3 and the source of the fourth switching tube Q6, and the other end is electrically connected to the negative branch, the first charge and discharge terminal is a negative electrode, and the second charge and discharge terminal is a positive electrode.

[0015] Preferably, the energy storage unit includes a first inductor L1 and a second inductor L2 that are magnetically coupled to each other, the drain of the first switching tube Q3 is electrically connected to the positive input terminal, and the source is electrically connected to the negative input terminal through the first inductor L1, the drain of the fourth switching tube Q6 is electrically connected to the first charge and discharge terminal, and the source is electrically connected to the second charge and discharge terminal through the second inductor L2 and the first inductor L1 in sequence, the first inductor L1 and the second inductor L2 transfer energy through magnetic coupling, the first charge and discharge terminal is the negative terminal, and the second charge and discharge terminal is the positive terminal.

[0016] Preferably, the energy storage unit includes an isolation transformer, which includes a primary winding and a secondary winding. The same-name end of the primary winding is electrically connected to the positive input end, and the opposite-name end is electrically connected to the drain of the first switch tube Q3. The source of the first switch tube Q3 is electrically connected to the negative input end. The same-name end of the secondary winding is electrically connected to the source of the fourth switch tube Q6, and the opposite-name end is electrically connected to the second charge and discharge end. The drain of the fourth switch tube Q6 is electrically connected to the first charge and discharge end. The first charge and discharge end is a positive electrode, and the second charge and discharge end is a negative electrode.

[0017] Preferably, the BMS and Buck-Boost converter integrated circuit further includes a first filter capacitor C1 and a second filter capacitor C2, wherein the first filter capacitor C1 is connected in parallel between the positive input terminal and the negative input terminal, and the second filter capacitor C2 is connected in parallel between the first charge and discharge terminal and the second charge and discharge terminal.

[0018] Preferably, the BMS and Buck-Boost converter integrated circuit also includes a current detection resistor R1 for detecting the charging and discharging current and a protection fuse F1 for overload protection. The current detection resistor R1 is connected in series in the current loop where the negative input terminal is located, and the protection fuse F1 is connected in series between the positive input terminal and the drain of the first switching tube Q3.

[0019] Preferably, the BMS and Buck-Boost converter integrated circuit further includes a control circuit. In the discharge working mode, the control circuit provides a PWM control signal to the first switch tube Q3, so that the first switch tube Q3 simultaneously realizes the DC / DC step-down conversion and BMS discharge control functions;

[0020] In the charging working mode, the control circuit provides a PWM control signal to the fourth switch tube Q6, so that the fourth switch tube Q6 can simultaneously realize the DC / DC boost conversion and BMS charging control functions.

[0021] Preferably, in the discharge operation mode, the control circuit further keeps the fourth switch tube Q6 in a conducting state to provide a current path.

[0022] Preferably, the control circuit further monitors the charge and discharge current through the current detection resistor R1;

[0023] When an overcurrent state is detected, the control circuit turns off the first switch tube Q3 in the discharge mode to simultaneously cut off the DC / DC conversion function and the BMS discharge function;

[0024] When an overcurrent state is detected, the control circuit turns off the fourth switch tube Q6 in the charging mode to cut off the DC / DC conversion function and the BMS charging function at the same time.

[0025] Preferably, in the discharge working mode, the second switch tube Q4 and the first switch tube Q3 are complementary turned on to achieve synchronous rectification;

[0026] In the charging mode, the third switch tube Q5 and the fourth switch tube Q6 are complementary turned on to achieve synchronous rectification.

[0027] Preferably, the first switch tube Q3 and the fourth switch tube Q6 are both MOSFETs, and each MOSFET includes a parasitic body diode, which provides a corresponding freewheeling path.

[0028] In a second aspect, the present invention provides an electronic device comprising the BMS and Buck-Boost converter integrated circuit as described above, wherein the electronic device is a combination of one or more of an energy storage system, an electric vehicle, and a portable power supply device.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] On the one hand, the present invention eliminates the need to design independent charge and discharge control switches Q1 and Q2 in traditional BMS by designing functional reuse of the first switch tube Q3 and the fourth switch tube Q6, thereby reducing the number of semiconductor devices. By reducing the number of electronic components, the BOM cost is directly reduced, and the PCB area requirement is reduced, further saving system costs. The reduction in the number of devices and the reduction in PCB area contribute to the miniaturization of the overall system, and the functional reuse of the switch tube simplifies the circuit topology and reduces the complexity of system design. On the other hand, the number of conducting devices in the current path is reduced, the total conduction loss of the system is reduced, and the overall energy conversion efficiency is improved.

[0031] The present invention has other features and advantages that will be apparent from or will be described in detail in the accompanying drawings and the following detailed description incorporated herein, which together serve to explain certain principles of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0033] Figure 1 It is a circuit diagram of the prior art.

[0034] Figure 2 1 is a circuit diagram of a BMS and a Buck-Boost converter integrated circuit according to the first embodiment.

[0035] Figure 3 It is from Figure 1 The topology of the existing technology evolved into Figure 2 's evolution process.

[0036] Figure 4 4 is a circuit diagram of a BMS and a Buck-Boost converter integrated circuit according to a second embodiment.

[0037] Figure 5 It is from Figure 1 The topology of the existing technology evolved into Figure 4 's evolution process.

[0038] Figure 6 4 is a circuit diagram of a BMS and a Buck-Boost converter integrated circuit according to a third embodiment.

[0039] Figure 7 It is from Figure 1 The topology of the existing technology evolved into Figure 6 's evolution process.

[0040] Figure 8 4 is a circuit diagram of a BMS and a Buck-Boost converter integrated circuit according to a fourth embodiment.

[0041] Figure 9 It is from Figure 1 The topology of the existing technology evolved into Figure 8 's evolution process. DETAILED DESCRIPTION

[0042] In order to explain in detail the possible application scenarios, technical principles, specific solutions that can be implemented, and the purpose and effects of this application, the following is a detailed description of the specific embodiments listed in conjunction with the accompanying drawings. The embodiments described herein are only used to more clearly illustrate the technical solutions of this application and are therefore only examples and are not intended to limit the scope of protection of this application.

[0043] See also Figures 1-9 The electronic device of the present invention includes a BMS and a Buck-Boost converter integrated circuit. The electronic device is at least suitable for use in energy storage systems, electric vehicles, portable power devices, and other scenarios. Of course, according to actual needs, it can also be applied to other application scenarios. The application scenarios of the electronic device of the present invention are not limited here.

[0044] The basic circuit of the BMS and Buck-Boost converter integrated circuit includes a positive input terminal 10, a negative input terminal 20, a first charge and discharge terminal 30, a second charge and discharge terminal 40, a first switch tube Q3, a fourth switch tube Q6 and an energy storage unit. The positive input terminal 10 is electrically connected to the positive electrode of the battery cell 50, the negative input terminal 20 is electrically connected to the negative electrode of the battery cell 50, the first charge and discharge terminal 30 and the second charge and discharge terminal 40 are electrically connected to the charger and / or load respectively, and the energy storage unit is electrically connected between the battery side circuit including the first switch tube Q3 and the charge and discharge side circuit including the fourth switch tube Q6.

[0045] It is understood that the energy storage unit is provided in the middle of the energy conversion process and is electrically connected between the battery-side energy conversion unit and the load-side energy conversion unit. Specifically, the battery-side energy conversion unit uses the first switch tube Q3 as the core control element and is responsible for energy conversion between the battery unit 50 and the energy storage unit, while the load-side energy conversion unit uses the fourth switch tube Q6 as the core control element and is responsible for energy conversion between the energy storage unit and the external charger and / or load. Depending on the specific circuit topology, the energy storage unit can adopt the form of an inductor, a coupled inductor, or an isolation transformer to achieve bidirectional energy transfer.

[0046] The first switch tube Q3 is multiplexed as a power switch tube of the DC / DC converter and a discharge control switch tube of the BMS. In the discharge working mode, the first switch tube Q3 responds to the PWM control signal to perform switching action to achieve step-down conversion, and at the same time acts as the BMS discharge control switch to control the discharge path of the battery unit 50 to be opened and closed.

[0047] The fourth switch tube Q6 is multiplexed as a power switch tube of the DC / DC converter and a charging control switch tube of the BMS. In the charging working mode, the fourth switch tube Q6 responds to the PWM control signal to perform switching action to achieve boost conversion, and at the same time acts as the BMS charging control switch to control the charging path of the battery unit 50 to be opened and closed.

[0048] According to the above basic circuit, the present invention has a four-switch Buck-Boost topology, a two-switch basic topology, a coupled inductor topology and a Flyback isolation transformer topology. These four topologies are described in detail below.

[0049] Example 1

[0050] See also Figure 2 and Figure 3 The BMS and Buck-Boost converter integrated circuit of this embodiment adopts a four-switch Buck-Boost topology. In addition to the above basic circuit, the integrated circuit further includes a second switch tube Q4 and a third switch tube Q5. The energy storage unit includes a first inductor L1. The source of the first switch tube Q3 and the drain of the second switch tube Q4 are electrically connected to form a first switch node. The drain of the third switch tube Q5 and the source of the fourth switch tube Q6 are electrically connected to form a second switch node. The first inductor L1 is electrically connected between the first and second switch nodes.

[0051] The negative input terminal 20 is electrically connected to the second charge and discharge terminal 40 to form a negative branch. The drain of the first switch tube Q3 is electrically connected to the positive input terminal 10, the source of the second switch tube Q4 is electrically connected to the negative branch, the drain of the fourth switch tube Q6 is electrically connected to the first charge and discharge terminal 30, and the source of the third switch tube Q5 is electrically connected to the negative branch. The first charge and discharge terminal 30 is a positive electrode, and the second charge and discharge terminal 40 is a negative electrode.

[0052] Figure 3 The BMS and Buck-Boost converter integrated circuit of this embodiment are shown. Figure 1 The topology of the existing technology evolved into Figure 2 's evolution process.

[0053] The battery unit 50 has a discharge mode (i.e., Buck step-down conversion) and a charge mode (i.e., Boost step-up conversion):

[0054] When the battery cell 50 operates in battery discharge mode, the first switch Q3 functions as the main Buck switch, with its on / off control controlled by a PWM signal. When the first switch Q3 is on, the energy stored in the battery is discharged to the load via the inductor (L1) and the fourth switch Q6 through the first and second output terminals. The first switch Q3 both implements Buck step-down conversion and controls the discharge path of the battery cell 50.

[0055] In the discharge mode, the second switch tube Q4 and the first switch tube Q3 are complementary turned on to achieve synchronous rectification, the fourth switch tube Q6 remains on to provide a current path, and the third switch tube Q5 remains off.

[0056] When battery cell 50 operates in battery charging mode, fourth switch Q6 serves as the main Boost switch, with its on / off control controlled by a PWM signal. When fourth switch Q6 is on, energy from the external power supply flows through fourth switch Q6 to inductor (L1) and first switch Q3 to charge battery cell 50. Fourth switch Q6 both implements Boost voltage conversion and controls the charging path for battery cell 50.

[0057] In the charging mode, the third switch tube Q5 and the fourth switch tube Q6 are complementarily turned on to achieve synchronous rectification, and the first switch tube Q3 remains in the off state, and the second switch tube Q4 remains in the off state.

[0058] Preferably, the first switch tube Q3, the second switch tube Q4, the third switch tube Q5, and the fourth switch tube Q6 of this embodiment are all MOSFETs, each MOSFET includes a parasitic body diode, the cathode of the parasitic body diode is connected to the drain of the corresponding MOSFET, and the anode is connected to the source of the corresponding MOSFET.

[0059] During the freewheeling period of the discharge mode, the parasitic body diode of the second switch tube Q4 or its conductive channel provides a freewheeling path; during the freewheeling period of the charge mode, the parasitic body diode of the third switch tube Q5 or its conductive channel provides a freewheeling path to ensure that the battery unit 50 can discharge normally.

[0060] Preferably, the integrated circuit of this embodiment further includes a first filter capacitor C1 and a second filter capacitor C2. The first filter capacitor C1 is connected in parallel between the positive input terminal 10 and the negative input terminal 20, and the second filter capacitor C2 is connected in parallel between the first charge and discharge terminal 30 and the second charge and discharge terminal 40. The first filter capacitor C1 and the second filter capacitor C2 are respectively used to filter fluctuation interference at the corresponding terminals.

[0061] Preferably, the integrated circuit of this embodiment also includes a current detection resistor R1 for detecting the charging and discharging current and a protection fuse F1 for overload protection. The current detection resistor R1 is connected in series in the current loop where the negative input terminal 20 is located, and the protection fuse F1 is connected in series between the positive input terminal 10 and the drain of the first switching tube Q3.

[0062] Preferably, the integrated circuit of this embodiment further includes a control circuit for realizing PWM control and protection functions of the switch tubes. The control circuit is respectively connected to the gate of each switch tube and is connected to the current detection resistor R1.

[0063] In the discharge mode, the control circuit provides a PWM control signal to the first switch Q3, enabling it to simultaneously implement DC / DC step-down conversion and BMS discharge control functions. In the charge mode, the control circuit provides a PWM control signal to the fourth switch Q6, enabling it to simultaneously implement DC / DC step-up conversion and BMS charge control functions.

[0064] The integrated protection function of the control circuit is specifically implemented as follows:

[0065] The charge and discharge current is monitored by the current detection resistor R1. When an overcurrent state is detected, the first switch tube Q3 is turned off in the discharge mode to simultaneously cut off the DC / DC conversion function and the BMS discharge function; in the charging mode, the fourth switch tube Q6 is turned off to simultaneously cut off the DC / DC conversion function and the BMS charging function.

[0066] It should be noted that the control circuit of this embodiment may adopt a conventional control circuit of the battery management type. Its specific implementation and circuit structure are not the focus of this embodiment and will not be described in detail here.

[0067] Example 2

[0068] See also Figure 4 and Figure 5 The BMS and Buck-Boost converter integrated circuit of this embodiment has a two-switch basic topology structure.

[0069] Compared to Example 1, this embodiment does not include the second switching transistor Q4 and the third switching transistor Q5, and the specific structure of the energy storage unit is different. Specifically, the energy storage unit includes a first inductor L1. The drain of the first switching transistor Q3 is electrically connected to the positive input terminal 10, and the source is electrically connected to the source of the fourth switching transistor Q6. The drain of the fourth switching transistor Q6 is electrically connected to the first charge and discharge terminal 30. The negative input terminal 20 and the second charge and discharge terminal 40 are electrically connected to form a negative branch. One end of the first inductor L1 is electrically connected to the connection point between the source of the first switching transistor Q3 and the source of the fourth switching transistor Q6, and the other end is electrically connected to the negative branch. The first charge and discharge terminal 30 is a negative electrode, and the second charge and discharge terminal 40 is a positive electrode.

[0070] Figure 5 The BMS and Buck-Boost converter integrated circuit of this embodiment are shown. Figure 1 The topology of the existing technology evolved into Figure 4 's evolution process.

[0071] It is understandable that this embodiment has a simpler structure and relatively simpler control, but still achieves functional reuse of the first switch Q3 and the fourth switch Q6. The first switch Q3 serves as both the Buck main switch and the BMS discharge control switch in discharge mode, and the fourth switch Q6 serves as both the Boost main switch and the BMS charge control switch in charge mode.

[0072] In addition, this embodiment further reduces the number of switches, lowering system complexity and cost, making it suitable for cost-sensitive applications. Although the number of power devices is reduced, good conversion efficiency can still be maintained through optimized control strategies.

[0073] Example 3

[0074] See also Figure 6 and Figure 7 , the BMS and Buck-Boost converter integrated circuit of this embodiment are a coupled inductor topology structure.

[0075] Compared to Example 1, this embodiment does not include the second switching transistor Q4 and the third switching transistor Q5, and the specific structure of the energy storage unit is different. Specifically, the energy storage unit includes a first inductor L1 and a second inductor L2 that are magnetically coupled to each other. The drain of the first switching transistor Q3 is electrically connected to the positive input terminal 10, and the source is electrically connected to the negative input terminal 20 through the first inductor L1. The drain of the fourth switching transistor Q6 is electrically connected to the first charge and discharge terminal 30, and the source is electrically connected to the second charge and discharge terminal 40 through the second inductor L2 and the first inductor L1 in sequence. The first inductor L1 and the second inductor L2 transfer energy through magnetic coupling, and the coupling coefficient generally needs to be above 0.9. The first charge and discharge terminal 30 is a negative electrode, and the second charge and discharge terminal 40 is a positive electrode.

[0076] Figure 7 The BMS and Buck-Boost converter integrated circuit of this embodiment are shown. Figure 1 The topology of the existing technology evolved into Figure 6 's evolution process.

[0077] It is understood that the BMS and Buck-Boost converter integrated circuit of this embodiment achieve energy transfer through magnetic coupling, which provides better electrical isolation than traditional single-inductor structures. Furthermore, magnetic coupling provides electrical isolation between the input and output sides, while the voltage ratio can be adjusted by designing the coupling coefficient. Furthermore, the first switch Q3 and the fourth switch Q6 still maintain functional multiplexing, integrating the DC / DC conversion function and the BMS control function in the discharge and charge modes, respectively.

[0078] In addition, this embodiment achieves electrical isolation between input and output through the coupled inductor design, improving system safety. At the same time, the magnetic coupling characteristics of the coupled inductor help reduce the inductor volume and increase power density.

[0079] Example 4

[0080] See also Figure 8 and Figure 9 , the BMS and Buck-Boost converter integrated circuit of this embodiment is a Flyback isolation transformer topology.

[0081] Compared to Example 1, this embodiment does not include the second switching transistor Q4 and the third switching transistor Q5, and the specific structure of the energy storage unit is different. Specifically, the energy storage unit includes an isolation transformer T1, which includes a primary winding T11 and a secondary winding T12. The same-name terminal of the primary winding T11 is electrically connected to the positive input terminal 10, and the opposite-name terminal is electrically connected to the drain of the first switching transistor Q3. The source of the first switching transistor Q3 is electrically connected to the negative input terminal 20. The same-name terminal of the secondary winding T12 is electrically connected to the source of the fourth switching transistor Q6, and the opposite-name terminal is electrically connected to the second charge and discharge terminal 40. The drain of the fourth switching transistor Q6 is electrically connected to the first charge and discharge terminal 30. The first charge and discharge terminal 30 is a positive electrode, and the second charge and discharge terminal 40 is a negative electrode.

[0082] Figure 9 The BMS and Buck-Boost converter integrated circuit of this embodiment are shown. Figure 1 The topology of the existing technology evolved into Figure 8 's evolution process.

[0083] It is understandable that the BMS and Buck-Boost converter integrated circuit of this embodiment are completely electrically isolated through the isolation transformer. The isolation transformer T1 not only plays the role of electrical isolation in the circuit, but also participates in the energy transfer process as an energy storage element.

[0084] When the first switch tube Q3 is turned on, the primary winding T11 stores magnetic energy; when the first switch tube Q3 is turned off, the secondary winding T12 releases magnetic energy to the output end, and the fourth switch tube Q6 serves as a synchronous rectifier tube for the secondary winding T12, realizing the multiplexing of the Boost function and the BMS charging control function.

[0085] Due to the isolation characteristics of the transformer, the primary winding T11 and the secondary winding T12 require independent control circuits or isolated control signal transmission. The control circuit controls the switching of the first switch Q3 on the primary side using a PWM signal and the fourth switch Q6 on the secondary side using a synchronous rectification control signal. Different voltage transformation ratios can be achieved by adjusting the transformer's turns ratio.

[0086] This embodiment achieves complete electrical isolation, offering the highest level of safety, making it suitable for safety-critical applications. The isolation transformer also provides multiple outputs, expanding system functionality while maintaining the core advantage of switch function reuse.

[0087] It can be seen from the above four embodiments that the innovation of the present invention lies in the functional multiplexing of the first switch tube Q3 and the fourth switch tube Q6, specifically:

[0088] 1. The first switch Q3 functions as both the power switch for the DC / DC converter and the discharge control switch for the BMS. In discharge mode, the first switch Q3 switches in response to a PWM control signal, implementing both the buck converter's step-down function and serving as the BMS discharge control switch to open and close the discharge path of the battery cell 50. This functional reuse eliminates the need for a separate discharge control switch in traditional BMSs.

[0089] 2. The fourth switch Q6 functions as both the power switch for the DC / DC converter and the charge control switch for the BMS. In charging mode, the fourth switch Q6 switches in response to a PWM control signal, implementing both the boost function and serving as the BMS charge control switch to open and close the charging path for the battery cell 50. This functional duplication eliminates the need for a separate charge control switch in traditional BMSs.

[0090] 3. The energy storage unit establishes an energy transfer path within the circuit. Depending on the topology, it can be a single inductor, a coupled inductor, or an isolation transformer. Regardless of the energy storage unit used, the dual functionality of the first and fourth switching transistors Q3 and Q6 is maintained, effectively integrating the lithium battery BMS with the buck-boost DC / DC converter into the circuit.

[0091] It should be noted that Figure 1 A circuit diagram of the prior art, Figure 3 、 Figure 5 、 Figure 7 and Figure 9 Respectively involved Figure 1 General topology of circuit diagrams, Figure 3 、 Figure 5 、 Figure 7 and Figure 9 The first to fourth embodiments are shown respectively. Figure 1 The evolution of general topology of circuit diagrams to aid understanding.

[0092] Combine Figures 1-9 , the present invention has the following beneficial effects:

[0093] On the one hand, the present invention eliminates the need to design independent charge and discharge control switches Q1 and Q2 in traditional BMS by designing functional reuse of the first switch tube Q3 and the fourth switch tube Q6, thereby reducing the number of semiconductor devices. By reducing the number of electronic components, the BOM cost is directly reduced, and the PCB area requirement is reduced, further saving system costs. The reduction in the number of devices and the reduction in PCB area contribute to the miniaturization of the overall system, and the functional reuse of the switch tube simplifies the circuit topology and reduces the complexity of system design. On the other hand, the number of conducting devices in the current path is reduced, the total conduction loss of the system is reduced, and the overall energy conversion efficiency is improved.

[0094] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments can still be modified, or some of the technical features thereof can be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A BMS and Buck-Boost converter integrated circuit, characterized in that: The battery comprises a positive input terminal, a negative input terminal, a first charge-discharge terminal, a second charge-discharge terminal, a first switch tube Q3, a fourth switch tube Q6, and an energy storage unit, wherein the positive input terminal is electrically connected to the positive electrode of the battery cell, the negative input terminal is electrically connected to the negative electrode of the battery cell, the first charge-discharge terminal and the second charge-discharge terminal are electrically connected to a charger and / or a load, respectively, and the energy storage unit is electrically connected between the battery side circuit including the first switch tube Q3 and the charge-discharge side circuit including the fourth switch tube Q6; The first switch tube Q3 is multiplexed as a power switch tube of the DC / DC converter and a discharge control switch tube of the BMS. In the discharge working mode, the first switch tube Q3 responds to the PWM control signal to perform switching action to achieve step-down conversion, and at the same time acts as the BMS discharge control switch to control the discharge path of the battery cell. The fourth switch tube Q6 is multiplexed as a power switch tube of the DC / DC converter and a charging control switch tube of the BMS. In the charging working mode, the fourth switch tube Q6 responds to the PWM control signal to perform switching action to achieve boost conversion, and at the same time acts as the BMS charging control switch to control the charging path of the battery unit to be opened and closed.

2. The BMS and Buck-Boost converter integrated circuit according to claim 1, wherein: The device further includes a second switching tube Q4 and a third switching tube Q5, the energy storage unit includes a first inductor L1, the source of the first switching tube Q3 and the drain of the second switching tube Q4 are electrically connected to form a first switching node, the drain of the third switching tube Q5 and the source of the fourth switching tube Q6 are electrically connected to form a second switching node, and the first inductor L1 is electrically connected between the first switching node and the second switching node; The negative input terminal is electrically connected to the second charge and discharge terminal to form a negative branch. The drain of the first switch tube Q3 is electrically connected to the positive input terminal. The source of the second switch tube Q4 is electrically connected to the negative branch. The drain of the fourth switch tube Q6 is electrically connected to the first charge and discharge terminal. The source of the third switch tube Q5 is electrically connected to the negative branch. The first charge and discharge terminal is a positive electrode, and the second charge and discharge terminal is a negative electrode.

3. The BMS and Buck-Boost converter integrated circuit according to claim 1, wherein: The energy storage unit includes a first inductor L1. The drain of the first switching tube Q3 is electrically connected to the positive input terminal, and the source is electrically connected to the source of the fourth switching tube Q6. The drain of the fourth switching tube Q6 is electrically connected to the first charge and discharge terminal. The negative input terminal and the second charge and discharge terminal are electrically connected to form a negative branch. One end of the first inductor L1 is electrically connected to the connection point between the source of the first switching tube Q3 and the source of the fourth switching tube Q6, and the other end is electrically connected to the negative branch. The first charge and discharge terminal is a negative electrode, and the second charge and discharge terminal is a positive electrode.

4. The BMS and Buck-Boost converter integrated circuit according to claim 1, wherein: The energy storage unit includes a first inductor L1 and a second inductor L2 that are magnetically coupled to each other. The drain of the first switching tube Q3 is electrically connected to the positive input terminal, and the source is electrically connected to the negative input terminal through the first inductor L1. The drain of the fourth switching tube Q6 is electrically connected to the first charge and discharge terminal, and the source is electrically connected to the second charge and discharge terminal through the second inductor L2 and the first inductor L1 in sequence. The first inductor L1 and the second inductor L2 transfer energy through magnetic coupling. The first charge and discharge terminal is a negative electrode, and the second charge and discharge terminal is a positive electrode.

5. The BMS and Buck-Boost converter integrated circuit according to claim 1, wherein: The energy storage unit includes an isolation transformer, which includes a primary winding and a secondary winding. The same-name end of the primary winding is electrically connected to the positive input terminal, and the opposite-name end is electrically connected to the drain of the first switch tube Q3. The source of the first switch tube Q3 is electrically connected to the negative input terminal. The same-name end of the secondary winding is electrically connected to the source of the fourth switch tube Q6, and the opposite-name end is electrically connected to the second charge and discharge terminal. The drain of the fourth switch tube Q6 is electrically connected to the first charge and discharge terminal. The first charge and discharge terminal is a positive terminal, and the second charge and discharge terminal is a negative terminal.

6. The BMS and Buck-Boost converter integrated circuit according to any one of claims 1 to 5, wherein: It also includes a first filter capacitor C1 and a second filter capacitor C2. The first filter capacitor C1 is connected in parallel between the positive input terminal and the negative input terminal, and the second filter capacitor C2 is connected in parallel between the first charge and discharge terminal and the second charge and discharge terminal.

7. The BMS and Buck-Boost converter integrated circuit according to any one of claims 1 to 5, characterized in that: It also includes a current detection resistor R1 for detecting charging and discharging current and a protection fuse F1 for overload protection. The current detection resistor R1 is connected in series in the current loop where the negative input terminal is located, and the protection fuse F1 is connected in series between the positive input terminal and the drain of the first switching tube Q3.

8. The BMS and Buck-Boost converter integrated circuit according to claim 7, wherein: The invention also includes a control circuit, which provides a PWM control signal to the first switch tube Q3 in the discharge working mode, so that the first switch tube Q3 can simultaneously realize the DC / DC step-down conversion and BMS discharge control functions; In the charging working mode, the control circuit provides a PWM control signal to the fourth switch tube Q6, so that the fourth switch tube Q6 can simultaneously realize the DC / DC boost conversion and BMS charging control functions.

9. The BMS and Buck-Boost converter integrated circuit according to claim 8, wherein: In the discharge working mode, the control circuit also keeps the fourth switch tube Q6 in the on state to provide a current path.

10. The BMS and Buck-Boost converter integrated circuit according to claim 8, wherein: The control circuit also monitors the charge and discharge current through the current detection resistor R1; When an overcurrent state is detected, the control circuit turns off the first switch tube Q3 in the discharge mode to simultaneously cut off the DC / DC conversion function and the BMS discharge function; When an overcurrent state is detected, the control circuit turns off the fourth switch tube Q6 in the charging mode to cut off the DC / DC conversion function and the BMS charging function at the same time.

11. The BMS and Buck-Boost converter integrated circuit according to claim 2, wherein: In the discharge working mode, the second switch tube Q4 and the first switch tube Q3 are complementary turned on to achieve synchronous rectification; In the charging mode, the third switch tube Q5 and the fourth switch tube Q6 are complementary turned on to achieve synchronous rectification.

12. The BMS and Buck-Boost converter integrated circuit according to any one of claims 1 to 11, wherein: The first switch tube Q3 and the fourth switch tube Q6 are both MOSFETs. Each MOSFET includes a parasitic body diode, and the parasitic body diode provides a corresponding freewheeling path.

13. An electronic device, characterized in that: The electronic device comprises the BMS and Buck-Boost converter integrated circuit according to any one of claims 1 to 12, wherein the electronic device is a combination of one or more of an energy storage system, an electric vehicle, and a portable power supply device.

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