Charging system and emergency starting device

Abstract

The present disclosure relates to the technical field of electronic circuits. Disclosed are a charging system and an emergency starting device. The charging system comprises a charging input interface, an inductor, a first switch, a second switch, a first voltage acquisition circuit, and control circuits. The charging input interface is electrically connected to the inductor, the inductor is further respectively connected to the first switch and the second switch, and the second switch is configured to be electrically connected to an energy storage power supply; the first voltage acquisition circuit is electrically connected to the second switch and is configured to measure, in real time, a first voltage outputted by the charging system; and a control circuit cyclically controls, turning-on time and turning-off time of the first switch on the basis of the first voltage. In the charging process of the charging system, when the first voltage is lower than a first preset voltage value, the control circuit controls the first switch to be turned on to start cyclic control, wherein the states of the first switch and the second switch are opposite. The charging system can achieve stable output, so as to maximize the charging efficiency of an automobile emergency start power supply.

Description

Charging system and emergency start device

[0001] Cross-reference of related applications

[0002] This disclosure claims priority to Chinese Patent Application No. 2024107060223, filed on May 31, 2024, entitled “Charging System and Emergency Start-up Device”.

[0003] Priority is given to Chinese Patent Application No. 2024212493687, filed with the Chinese Patent Office on May 31, 2024, entitled “Charging System and Emergency Start-up Device”, the entire contents of which are incorporated herein by reference. Technical Field

[0004] This disclosure relates to the field of electronic circuit technology, and in particular to a charging system and an emergency start device. Background Technology

[0005] The charging system of a car jump starter typically uses a dedicated charging management chip. This type of charging system requires the charger to be compatible with the charging circuit parameters inside the car jump starter. For example, if the design is a 10W charging circuit with 5V 2A, then the user needs to use a 5V 2A or higher charger.

[0006] However, when the charger deviates from its design specifications, for example, if the charger power is less than the designed charging power, it will trigger protection due to insufficient power, resulting in abnormal charging and potentially damaging the charger; or if the charger power is greater than the designed charging power, it will not be able to maximize the use of the charger's power, resulting in low charging efficiency and longer charging time. Summary of the Invention

[0007] In view of this, the present disclosure provides a charging system and an emergency start device that can achieve stable output based on the power of the charging circuit inside the vehicle's emergency start power supply, thereby maximizing charging efficiency.

[0008] In a first aspect, embodiments of this disclosure provide a charging system configured to charge an energy storage power source, the charging system including a charging input interface, an inductor, a first switch, a second switch, a first voltage acquisition circuit, and a control circuit;

[0009] The charging input interface is electrically connected to the first end of the inductor.

[0010] The second end of the inductor is electrically connected to the first end of the first switch and the first end of the second switch, respectively.

[0011] The second terminal of the first switch is electrically connected to the ground terminal, and the second terminal of the second switch is configured to be electrically connected to the energy storage power source.

[0012] The first voltage acquisition circuit is electrically connected to the second terminal of the second switch and is configured to detect the first voltage output by the charging system in real time.

[0013] The control circuit is electrically connected to the control terminals of the first voltage acquisition circuit and the first switch, respectively. The control circuit cyclically controls the on and off times of the first switch based on the first voltage.

[0014] During the charging process of the charging system, when the first voltage is less than the first preset voltage value, the control circuit controls the first switch to turn on and start the cycle control. When the first switch is in the on state, the second switch is in the off state, and when the first switch is in the off state, the second switch is in the on state.

[0015] Secondly, this disclosure provides an emergency start-up device, including: a built-in energy storage power supply and the charging system, wherein the second terminal of the second switch is electrically connected to the built-in energy storage power supply.

[0016] The embodiments disclosed herein have the following beneficial effects:

[0017] The charging system of this embodiment includes a charging input interface, an inductor, a first switch, a second switch, a first voltage acquisition circuit, and a control circuit. The charging input interface is electrically connected to the inductor, which is also connected to both the first and second switches. The second switch is configured to be electrically connected to an energy storage power source. The first voltage acquisition circuit is electrically connected to the second switch and configured to detect the first voltage output by the charging system in real time. The control circuit cyclically controls the on and off times of the first switch based on the first voltage. During the charging process, when the first voltage is less than a first preset voltage value, the control circuit controls the first switch to turn on to initiate cyclic control. When the first switch is on, the second switch is off; when the first switch is off, the second switch is on. This charging system can adjust the output of the charging system by controlling the first switch to turn on when the first voltage output by the charging system is less than the first preset voltage value, thereby achieving a stable output. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this disclosure and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 shows a schematic diagram of a charging system according to an embodiment of the present disclosure;

[0020] Figure 2 shows another structural schematic diagram of the charging system according to an embodiment of the present disclosure;

[0021] Figure 3 shows a schematic diagram of a first voltage acquisition circuit of a charging system according to an embodiment of the present disclosure;

[0022] Figure 4 shows a schematic diagram of the switching circuit of a charging system according to an embodiment of the present disclosure;

[0023] Figures 5(a) and 5(b) show schematic diagrams of a boost unit and a buck unit of a charging system according to an embodiment of the present disclosure, respectively.

[0024] Figure 6 shows a schematic diagram of a synchronous / asynchronous buck-boost unit of a charging system according to an embodiment of the present disclosure;

[0025] Figure 7 shows a schematic diagram of a second control circuit based on a totem pole drive discrete circuit of the charging system according to an embodiment of the present disclosure.

[0026] Figure 8 shows a schematic diagram of a second control circuit based on an integrated circuit in an embodiment of the charging system of this disclosure.

[0027] Figure 9 shows a schematic diagram of the structure of a battery protection unit of the charging system according to an embodiment of the present disclosure;

[0028] Figure 10 shows a schematic diagram of the structure of the emergency start-up device according to an embodiment of the present disclosure.

[0029] Key component symbols: 100-Charging system; 200-Energy storage power supply; 300-Emergency start device; 11-Charging input interface; 12-First voltage acquisition circuit; 13-Control circuit; 14-Switch circuit; 15-Second voltage acquisition circuit; 16-First current acquisition circuit; 17-Second current acquisition circuit; 18-First protection circuit; 19-Second protection circuit; 20-Third protection circuit; 21-Temperature sensor; 22-Charging status indication circuit; 23-Battery protection unit. Detailed Implementation

[0030] The technical solutions of the present disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present disclosure, and not all embodiments.

[0031] The components of the embodiments of this disclosure, typically described and illustrated in the accompanying drawings, can be arranged and designed in a variety of different configurations. Therefore, the following detailed description of the embodiments of this disclosure provided in the drawings is not intended to limit the scope of the claimed disclosure, but merely to illustrate selected embodiments of the disclosure. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without inventive effort are within the scope of this disclosure.

[0032] In the following, the terms “comprising,” “having,” and their cognates, which may be used in the various embodiments of this disclosure, are intended only to indicate a particular feature, number, step, operation, element, component, or combination thereof, and should not be construed as primarily excluding the presence of one or more other features, numbers, steps, operations, elements, components, or combinations thereof, or adding the possibility of one or more combinations thereof. Furthermore, the terms “first,” “second,” “third,” etc., are used only for distinguishing descriptions and should not be construed as indicating or implying relative importance.

[0033] Unless otherwise specified, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which the various embodiments of this disclosure pertain. Terms (such as those defined in a generally used dictionary) are to be interpreted as having the same meaning as in their contextual meaning in the relevant technical field and are not to be interpreted as having an idealized or overly formal meaning, unless clearly defined in the various embodiments of this disclosure.

[0034] The following detailed description of some embodiments of this disclosure is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0035] Figure 1 shows a schematic diagram of a charging system 100 according to an embodiment of the present disclosure.

[0036] Exemplarily, the charging system 100 is configured to charge the energy storage power supply 200, mainly including: a charging input interface 11, a switching circuit 14, a first voltage acquisition circuit 12, and a control circuit 13, etc. The switching circuit 14 includes an inductor, a first switch, and a second switch. Specifically, the charging input interface 11 is electrically connected to the first end of the inductor, the second end of the inductor is electrically connected to the first ends of both the first and second switches, the second end of the first switch is electrically connected to a ground terminal, and the second end of the second switch is configured to be electrically connected to the energy storage power supply 200. The first voltage acquisition circuit 12 is electrically connected to the second end of the second switch and is configured to detect the first voltage output by the charging system 100 in real time. The control circuit 13 is electrically connected to the control terminals of the first voltage acquisition circuit 12 and the first switch, respectively. For example, the aforementioned energy storage power supply 200 can be, but is not limited to, a vehicle emergency starting power supply.

[0037] In this embodiment, the charging input interface 11 is a universal serial bus connector, configured to connect to an external charger to charge the energy storage power supply 200. Exemplarily, the charging input interface 11 includes a first pin, a second pin, and a third pin. The first pin is the positive terminal (configured to connect to the positive power supply VCC), the second pin is the negative terminal (configured to connect to the negative power supply or ground GND), and the third pin is a signal terminal configured to communicate with the external charger. For example, the third pin can enable the external charger's fast charging function, allowing it to output different voltages to the charging system 100, ranging from 3.3V to 28V, specifically 5V, 9V, 12V, 15V, 20V, or 28V. It can be understood that the aforementioned first preset voltage value can be based on the voltage required by the energy storage power supply 200. For example, when the energy storage power supply 200 consists of four batteries connected in series, the first preset voltage value can be set to 16.8V, etc.

[0038] It is understandable that the structural design of the charging input interface 11 depends on the type of interface used to connect to the external charger. For example, it can use different types of interfaces such as USB 2.0 / 3.0, USB Type-A / B / C, or Lightning. Taking a USB Type-C connector as an example, the charging input interface 11 is configured to connect to a regular USB charger (i.e., one that does not support fast charging protocols) or one that supports QC (Quick Charge) fast charging protocols.

[0039] Optionally, to increase the overcurrent capability of the first and second pins, the charging input interface 11 can be configured with multiple pins connected in parallel in its hardware structure. For the third pin, to ensure normal operation when the charging input interface 11 is inserted from either side (e.g., using USB Type-C), the third pin can optionally be designed as two pins in its hardware structure, namely CC1 and CC2 as shown in Figure 2. This allows the external charger's output to be enabled via an external resistor or an external protocol chip.

[0040] Taking an external resistor as an example, as shown in Figure 2, in one embodiment, the charging system 100 includes a first resistor (i.e., R8 and R9 in Figure 2). One end of the first resistor is electrically connected to the third pin, and the other end of the first resistor is electrically connected to the second pin. For example, an external charger typically outputs a rated voltage, such as 5V. If a PD charger is connected, with the cooperation of the external resistors CC1 or CC2, the PD charger outputs a 5V voltage to the charging system 100. At this time, the control circuit 13 outputs a corresponding control signal, for example, a PWM control signal with the minimum duty cycle (such as 5%), and then controls the conduction of the first switch to obtain a voltage value (i.e., the first voltage mentioned above) output by the charging system 100.

[0041] Taking an external protocol chip as an example, in another embodiment, the charging system 100 includes a protocol chip electrically connected to a third pin. Optionally, the protocol chip is also configured to control the voltage between the first and second pins to be between 3.3V and 28V. The type or form of the protocol chip is not limited here.

[0042] For example, in one feasible implementation, the protocol chip is a microprocessor. Considering that the control circuit 13 in the charging system 100 may also include a microprocessor MCU, a single microprocessor MCU can be shared to reduce costs. Therefore, the aforementioned third pin can be electrically connected to the control circuit 13 and configured to receive control signals from the control circuit 13 to enable the external PD charger to output voltage to the charging system 100.

[0043] As an optional solution, if the connected USB charger supports fast charging protocols, the charging input interface 11 also includes a fourth and a fifth pin, such as the D+ and D- signal pins in the USB Type-C interface (as shown in Figure 2). These pins are connected to two pins of the control circuit 13 (i.e., signals ICPCK D+ and ICPCK D-) to enable communication between the control circuit 13 and the fast charger, thereby enabling fast charging voltage output, such as Qualcomm's QC2.0 and QC3.0 fast charging protocols.

[0044] In this embodiment, the first voltage acquisition circuit 12 is coupled to the output terminal of the charging system 100 and configured to acquire the output voltage of the charging system 100 (i.e., the first voltage mentioned above). When the charging system 100 is connected to an external charger and starts working, the control circuit 13 will output a corresponding control signal to control the first switch to turn on, so that the charging system 100 outputs a voltage value. At this time, the first voltage acquisition circuit 12 can acquire the corresponding first voltage. For example, in one embodiment, as shown in FIG3, the first voltage acquisition circuit 12 includes sampling resistors R30 and R31 and capacitor C7. One end of the sampling resistor R30 is configured to be connected to the output terminal of the charging system 100 (i.e., SYS_VCC in FIG3), and one end of the capacitor C7 is configured to be connected to a signal pin of the control circuit 13 (i.e., BAT_VFB in FIG3).

[0045] In this embodiment, the control circuit 13 can be configured to cyclically control the on and off times of the first switch based on a first voltage. Exemplarily, during the charging process of the charging system 100, when the first voltage is less than a first preset voltage value, the control circuit 13 controls the first switch to turn on and initiates cyclic control. Optionally, if the second switch is a directly controllable device, the control circuit 13 needs to control the first switch to turn on while the second switch is off. After entering cyclic control, the control circuit 13 synchronously controls the states of the first and second switches, wherein the states of the first and second switches are opposite; that is, when the first switch is on, the second switch is off, and when the first switch is off, the second switch is on. It can be understood that the first and second switches are jointly configured to achieve synchronous or asynchronous boost voltage conversion, with the second switch mainly serving as a freewheeling current source. It should be noted that the control of the first switch described above can be determined not only based on the first voltage but also by combining other voltage, current, and other parameters.

[0046] In this embodiment, the first switch can be a MOSFET or similar device. For example, as shown in Figure 4, the switch circuit 14 includes an inductor L1, a diode D1 (i.e., the second switch), a MOSFET Q2 (i.e., the first switch), and a resistor R12, etc. The first terminal of the first switch Q2 is the drain of the MOSFET, the second terminal is the source of the MOSFET, and the third terminal, electrically connected to the control circuit 13, is the gate of the MOSFET. It is understood that the connection method shown in Figure 4 is only one feasible example of the switch circuit 14 and is not the only limitation. Specific adjustments can be made according to the type and position of the MOSFET, etc.

[0047] Based on the premise that the first switch is a MOSFET, in one embodiment, the control signal configured to control the first switch can be a PWM (Pulse Width Modulation) control signal, etc. Specifically, when the control circuit 13 detects that the first voltage is less than a first preset voltage value, the control circuit 13 outputs a PWM control signal to control the switching circuit 14 to increase the on-time within one cycle, thereby increasing the output voltage of the charging system to reach the first preset voltage value, i.e., the constant voltage value required by the energy storage power supply 200. Conversely, optionally, when the first voltage is detected to be greater than the first preset voltage value, the control circuit 13 outputs a PWM control signal to control the first switch to decrease the on-time within one cycle, i.e., decrease the output voltage of the charging system to return to the first preset voltage value. It can be understood that the first preset voltage value is usually related to the charging cutoff voltage of the energy storage power supply 200, such as being set to 12.6-16.8V, etc.

[0048] It is worth noting that the switching circuit 14 formed by the first and second switches described above can be either a boost converter or a buck converter. For example, in a boost converter scenario, as shown in Figure 5(a), the first end of the inductor is connected to the input end of the charging system 100, and the two switches are positioned near the output end of the charging system 100 and are both connected to the second end of the inductor. In a buck converter scenario, as shown in Figure 5(b), the two switches are positioned near the input end of the charging system 100 and are both connected to the first end of the inductor, and the second end of the inductor is connected to the output end of the charging system 100.

[0049] The second switch mentioned above can be a diode or a MOSFET, etc. Taking a diode as an example, as shown in Figure 4 above, the first terminal of the second switch (i.e., D1 in Figure 4) is the anode of the diode, and the second terminal of the second switch (D1) is the cathode of the diode. Alternatively, taking a MOSFET as an example, the control terminal of the second switch (D1) is connected to the control circuit 13. The first terminal of the second switch (D1) can be the drain, and the second terminal can be the source, etc. The connection relationship between the drain and the source can be adjusted adaptively according to actual needs.

[0050] It is understandable that if the second switch is a diode, the first and second switches will be controlled asynchronously. This is because diodes have unidirectional conduction characteristics. In this case, the control circuit 13 only needs to control the first switch. Accordingly, the diode will adaptively conduct or cut off according to the direction of the current flowing through it, so that its on / off state is opposite to that of the first switch. If the second switch is a MOSFET, the first and second switches will be controlled synchronously. That is, the control circuit 13 outputs two completely complementary PWM control signals to control the first and second switches respectively.

[0051] As an alternative, considering that the charging system 100 may also be used for functions that sometimes require voltage boosting and sometimes voltage bucking, in one embodiment, the charging system 100 further includes a third switch and a fourth switch, as shown in FIG6. The first end of the third switch is electrically connected to the charging input interface 11, the second end of the third switch is electrically connected to the first end of the inductor and the first end of the fourth switch, respectively, the second end of the fourth switch is electrically connected to the ground terminal, and the control terminal of the third switch is electrically connected to the control circuit 13. The control circuit 13 is configured to cyclically control the on and off times of the third switch based on a first voltage.

[0052] During the startup process of the charging system 100, the four switches are controlled based on the magnitude of the input voltage of the charging system 100 and the first preset voltage value. For example, if the input voltage of the charging system 100 is detected to be greater than the first preset voltage value, the charging system 100 will operate in buck mode, and the third and fourth switches will operate under the control of the PWM signal output by the control circuit 13. Conversely, if the input voltage is detected to be less than the first preset voltage value, the charging system 100 will operate in boost mode, and the third switch will be in the on state, the fourth switch will be in the off state, and the first and second switches will operate under the control of the PWM signal output by the control circuit 13. After the charging system 100 has started up, it enters the process of charging the energy storage power supply. The states of the third and fourth switches are reversed: when the third switch is in the on state, the fourth switch is in the off state, and vice versa.

[0053] In one embodiment, during the charging process of the charging system, when the charging system 100 detects that the first voltage is less than a first preset voltage value, the control circuit 13 causes the third switch to be in the on state and the fourth switch to be in the off state; conversely, when the charging system 100 detects that the first voltage is greater than the first preset voltage value, the first switch is in the off state, and the control circuit 13 controls the third switch to be off to start cyclic control. It can be understood that by detecting that the output voltage is greater than a set value, i.e., the output voltage is too high, the control circuit 13 will control the third switch to switch from the previous on state to the off state, thereby reducing the output power. Furthermore, if the fourth switch uses a MOSFET, the states of the third and fourth switches are controlled synchronously.

[0054] In another embodiment, exemplaryly, during the charging process of the charging system 100, the four switches can be controlled accordingly based on the magnitude of the input voltage and output voltage of the charging system 100. For example, when the input voltage of the charging system 100 is detected to be greater than the output voltage (i.e., the first voltage), the first switch is turned off and the second switch is turned on, meaning the boost converter enters a non-operating (i.e., no boost) state. Simultaneously, the control circuit 13 cyclically controls the turning on and off of the third and fourth switches according to the relationship between the first voltage and the first preset voltage value, so that the first voltage remains equal to the first preset voltage value. Conversely, when the charging system 100 detects that the input voltage is less than the output voltage, the third switch is turned on and the fourth switch is turned off, meaning the buck converter enters a non-operating (i.e., no buck) state. Simultaneously, the control circuit 13 controls the first and second switches to cyclically turn on and off.

[0055] Optionally, based on the structure of the third switch being a MOSFET, in one embodiment, the control signal configured to control the third switch can be a PWM control signal or the like. Similar to the first and second switches described above, in one embodiment, the third switch can be a MOSFET, and the fourth switch can be a diode or a MOSFET. When the fourth switch is a diode, the first terminal of the fourth switch is the cathode of the diode, and the second terminal of the fourth switch is the anode of the diode. Similarly, if the fourth switch is a diode, the third and fourth switches will be controlled asynchronously. It can be understood that a diode has unidirectional conduction characteristics, and the control circuit 13 only needs to control the third switch. Accordingly, the diode will adaptively conduct or cut off according to the direction of the current flowing through it, so that its on / off state is opposite to that of the third switch. If the fourth switch is a MOSFET, the third and fourth switches will be controlled synchronously, that is, the control circuit 13 outputs two completely complementary PWM control signals to control the third and fourth switches respectively.

[0056] It can be understood that the switching circuit 14 in Figure 1 can be described as the above-mentioned boost conversion unit, buck conversion unit, or buck-boost conversion unit, and each unit includes asynchronous mode and synchronous mode. In other words, the switching circuit 14 can be a synchronous boost unit, an asynchronous boost unit, a synchronous buck unit, and an asynchronous buck unit.

[0057] Optionally, the charging system 100 also includes a first capacitor, one end of which is electrically connected to the second terminal of the second switch, and the other end of which is electrically connected to the ground terminal. It can be understood that the first capacitor, as an output capacitor, is located at the output terminal of the charging system 100, and can be configured to store electrical energy and also has a filtering function. The number of first capacitors is only an example here; the specific number can be set according to actual needs and is not limited here. For example, as shown in Figure 4, the first capacitor includes C13 and C23. Optionally, a second capacitor can also be provided before the switching circuit 14 as the input capacitor of the charging system 100, such as capacitors C4, C5, C6, and C10 shown in Figure 4.

[0058] In this embodiment, the control circuit 13 is configured to cyclically control the on and off states of the first switch. For example, the control circuit 13 can be implemented using a control chip capable of driving a MOSFET, or it can be implemented using a structure where the control chip and the drive circuit are separate. In one embodiment, the control circuit 13 includes a first control circuit 13 and a second control circuit 13. The first control circuit 13 is electrically connected to the first voltage acquisition circuit 12, and the second control circuit 13 is electrically connected to both the first control circuit 13 and the control terminal of the first switch. The first control circuit 13 generates a first control signal based on a first voltage and sends the first control signal to the second control circuit 13, so that the second control circuit 13 cyclically controls the on and off times of the first switch based on the first control signal. For example, as shown in FIG1, the first control circuit 13 can be a microprocessor, and the second control circuit 13 can be a drive circuit to increase the voltage and current intensity of the drive signal (such as a PWM signal), i.e., increase the drive capability. For example, the second control circuit 13 outputs a PWM control signal to the first switch to control the on time of the first switch, etc.

[0059] For the second control circuit 13, for example, in one embodiment, it can be composed of discrete components, such as a totem pole drive circuit, as shown in FIG7. The second control circuit 13 includes resistors R51 and R53 and common emitter transistors Q9 and Q11. The first terminal of resistor R51 is configured to input a signal from the microprocessor MCU (i.e., the first control signal) and output a PWM signal that drives the first switch through the common emitter.

[0060] Of course, in some other embodiments, the second control circuit 13 can also be implemented as an integrated circuit, as shown in Figure 8. For driving the first switch, the second control circuit 13 can be driven by an integrated chip U9 and peripheral circuits consisting of capacitors C22, C23, C24, diode D8, and resistors R18, R20, etc., and connected to the control circuit 13 through the pin PWMA. Optionally, if the second switch also uses a MOSFET, the second control circuit 13 may further include an integrated chip U10 and corresponding peripheral circuits consisting of capacitors C38, C41, C42, diode D10, and resistors R23, R24, etc., and connected to the control circuit 13 through the pin PWMB.

[0061] It is understood that the control circuit 13 in this embodiment refers to programs, circuits, systems, and subsystems, whether they are implemented in hardware, tangibly implemented in software, or both, and whether they are programmable. The term "control circuit" as used herein includes, but is not limited to, one or more computing devices, hardwired circuits, signal modification devices and systems, devices and machines configured to control systems, microprocessors, programmable devices and systems, field-programmable gate arrays, application-specific integrated circuits (ASICs), systems-on-a-chip, systems including discrete components and / or circuits, state machines, and any combination of the foregoing.

[0062] In addition, in some other embodiments, as shown in FIG1, the charging system 100 further includes a first current acquisition circuit 16, which is electrically connected to the control circuit 13 and the charging input interface 11, respectively, and is configured to detect a first current input to the charging input interface 11 (i.e., the input current of the charging system 100). The control circuit 13 cyclically controls the on and off times of the first switch based on the first voltage and / or the first current. In other words, the control circuit 13 can also use one or a combination of the output voltage and input current of the charging system 100 to control the first switch, thereby controlling the charging system 100 to achieve constant current or constant voltage charging. For example, as shown in FIG2, when the charging input interface 11 adopts a USB Type-C interface, the first current acquisition circuit 16 includes resistors R7, R11 and R18, wherein one end of resistor R18 (i.e., pin USB_IFB) is configured to be connected to the microcontroller MCU in the control circuit 13.

[0063] In one implementation, when the control circuit 13 detects that the first voltage is less than a first preset voltage value and the first current is less than a first preset current value, the control circuit 13 increases the output PWM control signal to control the first switch to conduct for a longer period within one cycle. It is understood that increasing the PWM control signal will increase the output voltage or input current of the charging system 100. Similar to the first preset voltage value mentioned above, the first preset current value is related to the charging current of the energy storage power supply 200 and can be set according to actual needs; no specific limitation is made here. For example, for the energy storage power supply 200, if its charging current is 2A, the first preset current value is usually set to 2A.

[0064] Of course, in scenarios where the limits on output voltage or input current are more stringent, in one implementation, if the first voltage is detected to be greater than the first preset voltage value, or the first current is detected to be greater than the first preset current value, i.e., one of the conditions of too high output voltage or too high input current occurs, the controller will reduce the output PWM control signal, such as reducing the duty cycle by 10-15%. Optionally, when the first voltage is detected to be greater than the first preset voltage value and the first current is detected to be greater than the first preset current value, i.e., both conditions are met simultaneously, the control circuit 13 adjusts the PWM control signal to reduce the on-time of the first switch in one cycle, i.e., reduce the output voltage or input current, to ensure constant current and constant voltage charging.

[0065] In some embodiments, as shown in FIG1, the charging system 100 further includes a second voltage acquisition circuit 15, which is electrically connected to the control circuit 13 and the charging input interface 11, respectively, and is configured to detect a second voltage input to the charging input interface 11 (i.e., the input voltage of the charging system 100). The control circuit 13 cyclically controls the on and off times of the first switch based on the first voltage and / or the second voltage. In other words, the control circuit 13 can also use one or a combination of the input voltage and output voltage of the charging system 100 to control the first switch, thereby controlling the output of the charging system 100.

[0066] For example, as shown in Figure 2, when the charging input interface 11 adopts a USB Type-C interface, the second voltage acquisition circuit 15 includes resistors R13 and R48, wherein the intermediate node of resistors R13 and R48 (i.e., pin DCIN_VFB) is configured to connect to the microcontroller MCU in the control circuit 13.

[0067] It is understandable that when controlling the first switch, if the charging system 100 detects through the second voltage acquisition circuit 15 that the second voltage is lower than the third preset voltage value, it will reduce the PWM signal to decrease the output power; conversely, if the second voltage is higher than the second preset voltage value, it will increase the PWM signal to increase the output power. It is also understandable that the charging system 100 can make a comprehensive judgment based on the input voltage and output voltage to achieve the adaptive charging function of the charger.

[0068] For example, in one implementation, when the second voltage is detected to be less than a third preset voltage value and the duration reaches a first preset time, the PWM control signal controls the first switch to reduce the on-time of the first switch within one cycle.

[0069] The purpose of setting the first preset time is to prevent the charger from entering a protection state due to overload during the second voltage drop. In other words, the first preset time should be set short so that the system can respond quickly to power reduction. For example, the range of the first preset time can be set to 10ms to 500ms, such as 50ms, 100ms, etc.

[0070] For example, in one implementation, when the second voltage is detected to be higher than the second preset voltage value and the duration reaches the second preset time, the PWM control signal controls the first switch to increase the on-time of the first switch within one cycle.

[0071] The purpose of setting the second preset time is to determine whether the external charger is in a stable load state. Power is only increased when the charger is indeed in a stable state; therefore, the second preset time must be longer than the first preset time. For example, the second preset time ranges from 10ms to 1s, such as 200ms or 250ms.

[0072] Furthermore, considering that the output voltage of the charging system 100 is relatively low, the power should be increased. However, it is also necessary to determine whether the input voltage of the charging system 100 meets the standard. The power increase is only allowed when the input voltage is greater than a certain voltage. For example, when the first voltage is detected to be less than the first preset voltage value and the second voltage is greater than the second preset voltage value, the control circuit 13 controls the first switch to increase the on-time of one cycle by outputting a PWM control signal.

[0073] Optionally, to ensure the normal operation of the charging system 100, exemplaryly, when the second voltage is less than the third preset voltage value, the control circuit 13 can control the first switch to reduce its on-time within one cycle by outputting a PWM control signal, thereby reducing power and allowing the second voltage to rise. It should be understood that if the second voltage is less than the third preset voltage value, it indicates an input overload (i.e., charger overload). Therefore, regardless of whether the first voltage and first current meet the first preset voltage and first preset current, the power must be reduced at this time. It is understood that both the third preset voltage value and the second preset voltage value are manually set; they can be set to be equal or unequal. In an optional scheme, there can be a difference between the aforementioned third preset voltage value and the second preset voltage value.

[0074] As an alternative, the control circuit 13 can also cyclically control the on and off times of the first switch based on the first voltage, the second voltage, and / or the first current, that is, use a combination of the first voltage, the first current, and the second voltage or one of them to achieve control.

[0075] For example, when the first voltage is detected to be less than the first preset voltage value, the first current is less than the first preset current value, and the second voltage is greater than the second preset voltage value, the control circuit 13 can increase the on-time of the first switch within one cycle by outputting a PWM control signal. It can be understood that by simultaneously considering the input voltage, input current, and output voltage to control the first switch, the charging system can better adapt to the external charger, thereby improving the charging efficiency of the energy storage power supply 200. Conversely, if the first voltage is detected to be greater than the first preset voltage value, or the first current is greater than the first preset current value, or the second voltage is less than the third preset voltage value, the on-time of the first switch within one cycle can be reduced by outputting a PWM control signal.

[0076] Optionally, if the first voltage is equal to the first preset voltage value or the first current is equal to the first preset current value, and the second voltage is greater than the third preset voltage value, the controller outputs the PWM control signal of the first switch unchanged. Optionally, if the second voltage is between the second and third preset voltage values, the controller circuit outputs the first control signal unchanged, which avoids frequent adjustment of the duty cycle of the first switch, causing the output to bounce back and forth. This is because increasing the power causes the voltage to drop immediately, leading to a reduction in power, which in turn causes the voltage to rise, and the voltage rise leads to a further increase in power.

[0077] Optionally, the difference between the third preset voltage value and the second preset voltage value can be greater than 100mV, such as 300mV, 500mV, etc., and can be adaptively set according to actual needs. For example, if the constant voltage input by the external charger is 5V, that is, when the second voltage is 5V, the second preset value can be 4.6V and the third preset value can be 4.3V; if the second voltage is 9V, the second preset value can be 8.3V and the third preset value can be 8.0V; and if the second voltage is 12V, the second preset value can be 11.0V and the third preset value can be 10.5V, etc. It can be understood that the second and third preset voltage values ​​will change with the change of the second voltage.

[0078] In another embodiment, as shown in FIG1, the charging system 100 further includes a second current acquisition circuit 17. The second current acquisition circuit 17 is electrically connected to the second terminal of the control circuit 13 and the second switch, respectively, and is configured to detect the second current output by the charging system 100. The control circuit 13 cyclically controls the on and off times of the first switch based on the first voltage and / or the second current. In other words, the control circuit 13 can use one or a combination of the output voltage and output current of the charging system 100 to control the first switch, thereby controlling the charging system 100 to achieve constant voltage or constant current charging. For example, the second current acquisition circuit 17 can sample the signal (not shown in the figure) from the second terminal (i.e., the output terminal) of the second switch through two sampling resistors connected in series and transmit it to the control circuit 13 to obtain the second current output by the charging system 100.

[0079] For example, in one embodiment, when the first voltage is detected to be less than a first preset voltage value and the second current is detected to be less than a second preset current value, i.e., based on the first voltage and the second current, the control circuit 13 controls the first switch to increase its conduction time within one cycle by outputting a PWM control signal. That is, when both the output voltage and output current of the charging system 100 are less than the set values, the control circuit 13 controls the PWM signal to increase the output voltage or output current of the charging system 100. Alternatively, in another embodiment, when the second current is detected to be greater than the second preset current value, i.e., the output current is too large, the control circuit 13 controls the output current to decrease to achieve constant current charging. In addition, the control circuit 13 can also control based on the first voltage, the second voltage, and the second current to achieve more precise adaptive charging with an external charger. The values ​​of the second preset current value and the first preset current value are selected according to actual needs and can be equal or unequal. For example, when constant current charging is required, the charging system 100 can determine whether the first current reaches the first preset current value or the second current reaches the second preset current value, and thus control the system to enter the constant current working mode.

[0080] It is understandable that if the charging system 100 includes the aforementioned second voltage acquisition circuit 15, first current acquisition circuit 16, and second current acquisition circuit 17, then when the control circuit 13 controls the first switch to increase, decrease, or maintain its conduction time within one cycle, it can combine at least two of the aforementioned first voltage, second voltage, first current, and second current. The specific combination can be set according to actual needs. By comprehensively considering these four parameters—first voltage, second voltage, first current, and second current—it is possible to better achieve charging management, such as input current limiting and output current limiting (for battery life), while achieving adaptive charging with an external charger.

[0081] In addition, in some other embodiments, the charging system 100 also includes a corresponding protection circuit to perform charging protection when parameters such as the first voltage, the second voltage, the first current and / or the second current do not meet the corresponding conditions, such as prohibiting the input and charging of the charging system 100.

[0082] As exemplarily shown in Figure 1, the charging system 100 also includes a first protection circuit 18, which is configured to prevent surge voltage and may also be configured to prevent static electricity. The location of the first protection circuit 18 can be on the line connected to the input circuit in the charging system 100, or after the charging input interface 11, etc., to provide surge protection at the moment of connection to an external charger. For example, the first protection circuit 18 can be implemented using a fuse, a discharge tube, etc., as shown in Figure 2, where TVS diodes Z1 and Z2 are configured to provide surge protection at the input terminal, instantly absorbing surge current to protect subsequent circuits.

[0083] Optionally, as shown in Figure 1, the charging system 100 further includes a second protection circuit 19. The second protection circuit 19 is electrically connected to the charging input interface 11 and is configured to prevent charging of the charging system 100 when the second voltage is greater than a fourth preset voltage value and the duration reaches a second preset time (i.e., the input voltage of the charging system 100 exceeds the corresponding preset value for a period of time). For example, assuming the second voltage is typically output at 5V, if it is detected that the second voltage is greater than 8V and lasts for 50ms, the second protection circuit 19 will perform charging protection.

[0084] As an optional solution, the second protection circuit 19 can also be combined with the control circuit 13 to realize input protection of the charging system 100. Exemplarily, the second protection circuit 19 is electrically connected to both the control circuit 13 and the charging input interface 11. The control circuit 13 is configured to output a control signal to the second protection circuit 19 when the second voltage is greater than a third preset voltage value and the duration reaches a second preset time. The second protection circuit 19 then prohibits charging of the charging system 100. For example, as shown in Figure 2, the second protection circuit 19 includes resistors R46, R49, R50, a Zener diode D5, a transistor Q3, a MOSFET Q5, and a capacitor C35. Resistor R46 is connected in parallel with Zener diode D5 and then connected to the power input terminal DC_IN. MOSFET Q5 is configured to be in a turned-off state when the second voltage is greater than 11V, thus preventing DC_IN from being input through the charging input interface 11.

[0085] As another optional solution, as shown in Figure 1, the charging system 100 also includes a third protection circuit 20. The third protection circuit 20 is electrically connected to the second terminal of the second switch. The third protection circuit 20 is configured to control the first voltage below the fifth preset voltage value when the first voltage exceeds a fifth preset voltage value for a duration of a third preset time. It can be understood that the third protection circuit 20 is configured to achieve output protection of the charging system 100, especially when the output voltage is too high (e.g., exceeding 17V), it needs to be controlled within the target voltage range. For example, the third protection circuit 20 includes a Zener diode, etc.

[0086] Furthermore, as shown in Figure 1, the charging system 100 also includes a battery protection unit 23. The battery protection unit 23 is electrically connected to the second terminal of the second switch and is configured to reduce the on-time of the first switch after the energy storage battery has finished charging, thereby reducing the output power or stopping charging, thus achieving charging protection and improving the service life of the energy storage power supply 200. For example, Figure 9 shows a lithium battery protection unit 23, which includes a protection chip U1 specifically for lithium batteries or polymer batteries and its corresponding peripheral devices. It is connected to the battery socket CN1 and configured to achieve charging protection.

[0087] As an optional solution, as shown in Figure 1, the charging system 100 further includes a temperature sensor 21. The temperature sensor 21 is disposed within a preset distance range of the first switch and / or inductor. In other words, the temperature sensor 21 is configured to be disposed within a preset distance range of the first switch and / or inductor to detect the temperature of the switch and / or inductor. It can be understood that by placing the temperature sensor 21 near the switch and / or inductor to collect the temperature of the power device, when the temperature reaches a preset temperature threshold (such as 90°C, 100°C, etc.), the control circuit 13 stops the charging system 100 from operating, thereby achieving temperature protection.

[0088] As an optional solution, as shown in Figure 1, the charging system 100 also includes a charging status indicator circuit 22, configured to indicate the power level, charging status (e.g., charging in progress, charging complete), and related parameters (e.g., first voltage, second voltage, first current, second current, temperature value) of the energy storage power supply 200. For example, it can be implemented using LED lights, digital tubes, LCD displays, etc.

[0089] The charging system 100 proposed in this disclosure adjusts the charging power by combining the variation range of at least one of output voltage and output current, input voltage and input current, etc., so as to achieve self-adaptation for various chargers with different power. Moreover, the charging input interface 11 is provided with three pins, including an enable signal pin, which can enable special functions such as fast charging and adapt to different types of chargers, such as PD chargers, fast chargers, etc., so as to maximize compatibility with various specifications of chargers, improve charging efficiency, and save energy.

[0090] Furthermore, this disclosure also proposes an emergency start device 300, exemplary as shown in FIG10. The emergency start device 300 includes: the aforementioned charging system 100 and a built-in energy storage power supply 200, wherein the second terminal of the second switch is electrically connected to the built-in energy storage power supply 200. It is understood that the options regarding the aforementioned charging system 100 also apply to this embodiment, and will not be repeated here.

[0091] In the several embodiments provided in this disclosure, it should be understood that the disclosed apparatus and methods can also be implemented in other ways. The apparatus embodiments described above are merely illustrative; for example, the flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of apparatus, methods, and computer program products according to various embodiments of this disclosure. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions configured to perform a specified logical function. It should also be noted that, as an alternative implementation, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagram and / or flowchart, and combinations of blocks in the block diagram and / or flowchart, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0092] In addition, the functional modules or units in the various embodiments of this disclosure can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0093] If the aforementioned functions are implemented as software functional modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this disclosure, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a smartphone, personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this disclosure. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0094] The above description is merely a specific embodiment of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Industrial applicability

[0095] Using the above scheme, during the charging process of the charging system, when the first voltage is less than the first preset voltage value, the control circuit controls the first switch to turn on and start the cyclic control. When the first switch is in the on state, the second switch is in the off state, and when the first switch is in the off state, the second switch is in the on state. This achieves stable output of the charging system through cyclic control when the first voltage output by the charging system is less than the first preset voltage value.

Claims

1. A charging system configured to charge an energy storage power source, characterized in that, The charging system includes a charging input interface, an inductor, a first switch, a second switch, a first voltage acquisition circuit, and a control circuit. The charging input interface is electrically connected to the first end of the inductor. The second end of the inductor is electrically connected to the first end of the first switch and the first end of the second switch, respectively. The second terminal of the first switch is electrically connected to the ground terminal, and the second terminal of the second switch is configured to be electrically connected to the energy storage power source. The first voltage acquisition circuit is electrically connected to the second terminal of the second switch and is configured to detect the first voltage output by the charging system in real time. The control circuit is electrically connected to the control terminals of the first voltage acquisition circuit and the first switch, respectively. The control circuit cyclically controls the on and off times of the first switch based on the first voltage. During the charging process of the charging system, when the first voltage is less than the first preset voltage value, the control circuit controls the first switch to turn on and start the cycle control. When the first switch is in the on state, the second switch is in the off state, and when the first switch is in the off state, the second switch is in the on state.

2. The charging system according to claim 1, characterized in that, The first switch is a MOSFET, the second switch is a diode, the first terminal of the second switch is the anode of the diode, and the second terminal of the second switch is the cathode of the diode.

3. The charging system according to claim 1, characterized in that, The control circuit outputs a PWM control signal to the first switch.

4. The charging system according to claim 3, characterized in that, The PWM control signal controls the first switch to increase the on-time within one cycle.

5. The charging system according to claim 4, characterized in that, When the first voltage is greater than the first preset voltage value, the PWM control signal controls the first switch to reduce the on-time within one cycle.

6. The charging system according to claim 1, characterized in that, The first switch is a MOSFET, the second switch is a MOSFET, and the control terminal of the second switch is connected to the control circuit.

7. The charging system according to claim 1, characterized in that, The charging system further includes a first capacitor, one end of which is electrically connected to the second terminal of the second switch, and the other end of which is electrically connected to the ground terminal.

8. The charging system according to claim 1, characterized in that, The charging input interface is a universal serial bus connector.

9. The charging system according to claim 8, characterized in that, The charging input interface includes a first pin, a second pin, and a third pin. The first pin is the positive terminal, the second pin is the negative terminal, and the third pin is the signal terminal. The third pin is configured to communicate with an external charger.

10. The charging system according to claim 9, characterized in that, The charging system includes a first resistor, one end of which is electrically connected to the third pin, and the other end of which is electrically connected to the second pin.

11. The charging system according to claim 9, characterized in that, The charging system includes a protocol chip, which is electrically connected to the third pin.

12. The charging system according to claim 11, characterized in that, The protocol chip controls the voltage between the first pin and the second pin to be between 3.3V and 28V.

13. The charging system according to claim 9, characterized in that, The control circuit is a microprocessor, and the third pin is electrically connected to the control circuit.

14. The charging system according to claim 3, characterized in that, The charging system further includes a first current acquisition circuit, which is electrically connected to the control circuit and the charging input interface, respectively, and is configured to detect a first current input to the charging input interface. The control circuit cyclically controls the on and off time of the first switch based on the first voltage and / or the first current.

15. The charging system according to claim 14, characterized in that, When the first voltage is less than the first preset voltage value and the first current is less than the first preset current value, the PWM control signal controls the first switch to increase the on-time within one cycle.

16. The charging system according to claim 15, characterized in that, When the first voltage is greater than the first preset voltage value, or the first current is greater than the first preset current value, the PWM control signal controls the first switch to reduce the on-time within one cycle.

17. The charging system according to claim 3, characterized in that, The charging system further includes a second voltage acquisition circuit, which is electrically connected to the control circuit and the charging input interface, respectively, and is configured to detect a second voltage input to the charging input interface. The control circuit cyclically controls the on and off time of the first switch based on the first voltage and / or the second voltage.

18. The charging system according to claim 17, characterized in that, When the first voltage is less than the first preset voltage value and the second voltage is greater than the second preset voltage value, the PWM control signal controls the first switch to increase the on-time within one cycle.

19. The charging system according to claim 17, characterized in that, When the first voltage is greater than the first preset voltage value, or the second voltage is less than the third preset voltage value, the PWM control signal controls the first switch to reduce the on-time within one cycle.

20. The charging system according to claim 17, characterized in that, When the second voltage is less than the third preset voltage value and the duration reaches the first preset time, the PWM control signal controls the first switch to reduce the on-time within one cycle.

21. The charging system according to claim 3, characterized in that, The charging system further includes a second current acquisition circuit, which is electrically connected to the second terminal of the control circuit and the second switch, respectively, and is configured to detect the second current output by the charging system. The control circuit cyclically controls the on and off time of the first switch based on the first voltage and / or the second current.

22. The charging system according to claim 21, characterized in that, When the first voltage is less than the first preset voltage value and the second current is less than the second preset current value, the PWM control signal controls the first switch to increase the on-time within one cycle.

23. The charging system according to claim 1, characterized in that, The charging system further includes a first protection circuit configured to prevent static electricity and / or surge voltage.

24. The charging system according to claim 1, characterized in that, The charging system further includes a second protection circuit, which is electrically connected to the charging input interface and configured to prohibit charging of the charging system when the second voltage input to the charging input interface is greater than a fourth preset voltage value and the duration reaches a second preset time.

25. The charging system according to claim 1, characterized in that, The charging system further includes a second protection circuit, which is electrically connected to the control circuit and the charging input interface. The control circuit is configured to output a control signal to the second protection circuit when the second voltage input at the charging input interface is greater than a fourth preset voltage value and the duration reaches a second preset time. The second protection circuit then prohibits the charging of the charging system.

26. The charging system according to claim 1, characterized in that, The charging system further includes a third protection circuit, which is electrically connected to the second terminal of the second switch and configured to control the first voltage below the fifth preset voltage value when the first voltage is greater than the fifth preset voltage value and the duration reaches the third preset time.

27. The charging system according to claim 26, characterized in that, The third protection circuit includes a Zener diode.

28. The charging system according to claim 1, characterized in that, The control circuit includes a first control circuit and a second control circuit. The first control circuit is electrically connected to the first voltage acquisition circuit, and the second control circuit is electrically connected to the control terminals of the first control circuit and the first switch, respectively. The first control circuit generates a first control signal based on the first voltage, and the second control circuit cyclically controls the on and off times of the first switch based on the first control signal.

29. The charging system according to claim 28, characterized in that, The second control circuit is a totem pole drive discrete circuit or a chip integrated circuit.

30. The charging system according to claim 28, characterized in that, The second control circuit outputs a PWM control signal to the first switch.

31. The charging system according to claim 1, characterized in that, The charging system also includes a temperature sensor, which is located within a preset distance range of the first switch and / or the inductor.

32. The charging system according to claim 1, characterized in that, The charging system further includes a third switch and a fourth switch. The first terminal of the third switch is electrically connected to the charging input interface. The second terminal of the third switch is electrically connected to the first terminal of the inductor and the first terminal of the fourth switch, respectively. The second terminal of the fourth switch is electrically connected to the ground terminal. The control terminal of the third switch is electrically connected to the control circuit. The control circuit is configured to cyclically control the on and off times of the third switch based on the first voltage. During the charging process of the charging system, when the first voltage is less than the first preset voltage value, the third switch is in the on state and the fourth switch is in the off state. When the first voltage is greater than the first preset voltage value, the first switch is in the off state. The control circuit controls the third switch to turn off and starts the cycle control. When the third switch is in the on state, the fourth switch is in the off state. When the third switch is in the off state, the fourth switch is in the on state.

33. The charging system according to claim 32, characterized in that, The third switch is a MOSFET, the fourth switch is a diode, the first terminal of the fourth switch is the cathode of the diode, and the second terminal of the fourth switch is the anode of the diode.

34. The charging system according to claim 32, characterized in that, The control circuit outputs a PWM control signal to the third switch.

35. The charging system according to claim 32, characterized in that, When the first voltage is greater than the first preset voltage value and the duration reaches the second preset time, the control circuit controls the third switch to turn off and start the cycle control.

36. An emergency start-up device, characterized in that, include: The built-in energy storage power supply and the charging system according to any one of claims 1-35, wherein the second terminal of the second switch is electrically connected to the built-in energy storage power supply.

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