State detection circuit, battery management system and battery pack

Abstract

The utility model discloses a state detection circuit, a battery management system and a battery pack, and relates to the technical field of detection circuits. The battery management system includes an electronic device; the state detection circuit comprises an acquisition circuit which is connected in series in an electrical loop between the electronic equipment and a power supply end; comprising a diode module, an anode of the diode module is electrically connected with the acquisition circuit, a cathode of the diode module is grounded, and the diode module is used for acquiring current of the electronic equipment and outputting a corresponding first voltage signal through the anode of the diode module; the input end of the signal conditioning circuit is electrically connected with the anode of the diode module, and the signal conditioning circuit is used for conditioning the first voltage signal and then outputting a conditioning detection signal; and the control circuit is electrically connected with the output end of the signal conditioning circuit and is used for receiving the conditioning detection signal output by the signal conditioning circuit so as to confirm the working state of the electronic equipment. The utility model aims to improve the detection precision of the battery management system on the electronic equipment therein.

Description

TECHNICAL FIELD

[0001] The utility model relates to detection circuit technical field, especially relate to a state detection circuit, battery management system and battery package. BACKGROUND

[0002] With the increasing demand for clean energy and the improvement of environmental awareness, new energy technology is rapidly developing. Small lithium battery package as an energy storage solution plays an increasingly important role in new energy systems such as portable electronic devices, Internet of Things (IoT) devices, and communication base station backup power. Especially in shared electric bicycles and portable power, the application of small lithium battery communication base station backup power becomes more widespread. In these scenarios, due to portability, special sensing devices need to be added for human motion sensing (such as interaction, safety, theft prevention, etc.), but such devices need to work in real time, and in addition, they are usually small battery packages (which can also not be particularly large in terms of available power), so their power consumption needs to be exceptionally low, and whenever there is a human interaction signal, they need to activate immediately.

[0003] Based on the above requirements, when redesigning the battery management system of the small lithium battery package, gyroscopes, Bluetooth, NB-lot, and other electronic devices are generally added, and when not working, the host will generally put them into hibernation, but the host cannot let them hibernate all the time, because the host needs to know if they are still online. Therefore, the corresponding technology is needed to detect whether the low-power electronic device is online.

[0004] The prior art generally adds a current sensor to sample the current from the device power supply loop, and outputs a voltage value to the single-chip microcomputer sampling port, but this cannot handle uA-level work of low-power electronic devices; even with complex sampling and analog amplification circuit conditioning, there is still a risk of false collection.

[0005] In the prior art, there is also a solution that uses an indefinite period of communication to determine whether it is running normally. This solution cannot be applied to low-power electronic devices without communication. At the same time, since it will periodically wake up for a period of time and then enter low-power mode, it still essentially increases the power consumption of the small battery package. UTILITY MODEL CONTENT

[0006] The main purpose of the utility model is to provide a state detection circuit, battery management system and battery package, which aims to improve the detection accuracy of the battery management system for electronic devices.

[0007] To achieve the above purpose, the state detection circuit provided by the utility model is applied to a battery management system, and the battery management system includes an electronic device; the state detection circuit includes:

[0008] A data acquisition circuit is connected in series in the electrical circuit between the electronic device and the power supply terminal; the data acquisition circuit includes a diode module, the anode of the diode module is electrically connected to the data acquisition circuit, and the cathode of the diode module is grounded;

[0009] The acquisition circuit is used to acquire the current of the electronic device and output a corresponding first voltage signal through the anode of the diode module;

[0010] A signal conditioning circuit, wherein the input terminal of the signal conditioning circuit is electrically connected to the anode of the diode module; the signal conditioning circuit is used to output a conditioning detection signal after the first voltage signal is conditioned.

[0011] A control circuit is electrically connected to the output terminal of the signal conditioning circuit; the control circuit is used to receive the conditioning detection signal output by the signal conditioning circuit to confirm the working status of the electronic device.

[0012] In one embodiment, the diode module includes a diode, the anode of which is electrically connected to the electronic device, and the cathode of which is electrically connected to ground; or,

[0013] The diode module includes a first diode to an Nth diode connected in series. The cathode of the first diode is grounded, the anode of the Nth diode is electrically connected to an electronic device, and the anode of the (n-1)th diode is connected to the cathode of the nth diode.

[0014] Wherein, N is a positive integer greater than or equal to 2, and n is a positive integer greater than 1 and less than or equal to N.

[0015] In one embodiment, N is 2, and the diode module includes a first diode, a second diode, and a first resistor;

[0016] The anode of the first diode is electrically connected to the electronic device, the first terminal of the first resistor, and the input terminal of the signal conditioning circuit; the cathode of the first diode is electrically connected to the anode of the second diode; and the cathode of the second diode is electrically connected to the second terminal of the first resistor and the ground terminal.

[0017] In one embodiment, the signal conditioning circuit includes a signal amplification circuit, the input terminal of which is electrically connected to the output terminal of the acquisition circuit, and the output terminal of which is electrically connected to the control circuit; the signal amplification circuit is used to receive the first voltage signal and output an amplified detection signal after amplifying the first voltage signal.

[0018] In one embodiment, the signal amplification circuit includes a second resistor, a third resistor, and an operational amplifier;

[0019] Wherein, the first end of the second resistor is electrically connected to the ground terminal, the second end of the second resistor is electrically connected to the inverting input terminal of the operational amplifier and the first end of the second resistor; the second end of the third resistor is electrically connected to the output terminal of the operational amplifier and the control circuit; the non-inverting input terminal of the operational amplifier is electrically connected to the output terminal of the acquisition circuit.

[0020] In one embodiment, the signal conditioning circuit further includes:

[0021] A first filtering circuit, wherein the input terminal of the first filtering circuit is electrically connected to the output terminal of the acquisition circuit, and the output terminal of the first filtering circuit is electrically connected to the input terminal of the signal amplification circuit; the first filtering circuit is used to receive the first voltage signal output by the first filtering circuit, and output it after filtering.

[0022] The second filter circuit has its input terminal electrically connected to the output terminal of the signal amplification circuit, and its output terminal electrically connected to the control circuit. The second filter circuit is used to receive the amplified detection signal output by the signal amplification circuit, and output a conditioned detection signal after filtering.

[0023] In one embodiment, the first filter circuit includes a fourth resistor and a first capacitor;

[0024] The first end of the fourth resistor is electrically connected to the output end of the acquisition circuit, and the second end of the fourth resistor is electrically connected to the first end of the first capacitor and the input end of the signal amplification circuit; the second end of the first capacitor is electrically connected to the ground terminal.

[0025] In one embodiment, the second filter circuit includes a fifth resistor and a second capacitor;

[0026] The first end of the fifth resistor is electrically connected to the output end of the signal amplification circuit, and the second end of the fifth resistor is electrically connected to the first end of the second capacitor and the control circuit; the second end of the second capacitor is electrically connected to the ground terminal.

[0027] This utility model also proposes a battery management system, which includes electronic equipment and a state detection circuit as described in any of the above claims.

[0028] This utility model also proposes a battery pack, wherein the battery includes the battery management system as described above.

[0029] This invention employs a state detection circuit, which effectively improves the detection accuracy of electronic devices within a battery management system. The state detection circuit includes a data acquisition circuit, a signal conditioning circuit, and a control circuit. The data acquisition circuit, comprising a diode module connected in series in the electrical circuit between the electronic device and the power supply, with the anode of the diode module electrically connected to the acquisition circuit and the cathode grounded, acquires the current of the electronic device and outputs a corresponding first voltage signal via the anode of the diode module. Furthermore, the signal conditioning circuit conditions the input first voltage signal, outputting a conditioned detection signal so that the control circuit can accurately determine the operating state of the electronic device. By utilizing the characteristics of the diode module, the current of the electronic device can be obtained more precisely. Therefore, the detection accuracy of the electronic devices within the battery management system can be effectively improved. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0031] Fig. 1 This is a schematic diagram of the state detection circuit of this utility model;

[0032] Fig. 2 This is a schematic diagram of a module of an embodiment of the state detection circuit of this utility model;

[0033] Fig. 3 This is a circuit diagram of the state detection circuit of this utility model.

[0034] Explanation of icon numbers:

[0035] 10. Acquisition circuit; 11. Diode module; 20. Signal conditioning circuit; 21. Signal amplification circuit; 22. First filter circuit; 23. Second filter circuit; 30. Control circuit; D1-D2, first diode-second diode; R1-R5, first resistor-fifth resistor; C1-C2, first capacitor-second capacitor; OPA, operational amplifier.

[0036] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0037] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0038] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in this utility model embodiment are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0039] Furthermore, the use of terms such as "first" and "second" in this utility model is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this utility model.

[0040] With increasing global demand for clean energy and growing environmental awareness, new energy technologies are developing rapidly. Small lithium-ion battery packs, as energy storage solutions, are playing an increasingly important role in new energy systems such as portable electronic devices, Internet of Things (IoT) devices, and backup power supplies for communication base stations. Their application is particularly widespread in shared electric bicycles and portable power banks, serving as backup power supplies for communication base stations. In these scenarios, due to their portability, special sensing devices are needed for human-like motion perception (e.g., interaction, security, anti-theft). However, these devices need to operate in real-time, and given that they are typically small battery packs (which don't have a particularly large capacity), their power consumption must be exceptionally low, and they must be activated immediately whenever a human interaction signal is detected.

[0041] Based on the above requirements, when designing a battery management system for a small lithium battery pack, electronic devices such as gyroscopes, Bluetooth, and NB-IoT are typically incorporated. When not in use, these devices are usually put into sleep mode by the host computer. However, the host computer cannot keep them in sleep mode indefinitely, as it needs to know whether they are still online. Therefore, corresponding technologies are required to detect whether low-power electronic devices are online.

[0042] Existing technologies typically involve adding a current sensor to the power supply circuit of the device to sample the current and outputting the voltage value to the microcontroller's sampling port. However, this approach cannot handle low-power electronic devices operating at the uA level. Even with complex sampling and analog amplification circuitry, erroneous data acquisition is still possible.

[0043] In existing technologies, there is another approach that uses intermittent communication to determine whether the device is operating normally. This approach cannot be applied to low-power electronic devices without communication capabilities. Furthermore, because it periodically wakes up and operates for a period before entering low-power mode, it inherently increases the power consumption of the small battery pack.

[0044] Therefore, refer to Figs. 1 to 3 To address the aforementioned problems, this utility model proposes a state detection circuit applied to a battery management system, wherein the battery management system includes electronic equipment; the state detection circuit includes:

[0045] The acquisition circuit 10 is connected in series in the electrical circuit between the electronic device and the power supply terminal; the acquisition circuit 10 includes a diode module 11, the anode of the diode module 11 is electrically connected to the acquisition circuit 10, and the cathode of the diode module 11 is grounded;

[0046] The acquisition circuit 10 is used to acquire the current of the electronic device and output a corresponding first voltage signal through the anode of the diode module 11;

[0047] The signal conditioning circuit 20 is electrically connected to the anode of the diode module 11. The signal conditioning circuit 20 is used to output a conditioning detection signal after the first voltage signal is conditioned.

[0048] A control circuit 30 is electrically connected to the output terminal of the signal conditioning circuit; the control circuit 30 is used to receive the conditioning detection signal output by the signal conditioning circuit to confirm the working status of the electronic device.

[0049] In this embodiment, the acquisition circuit 10 can be implemented using a current detection circuit including a diode module 11. The diode module 11 includes diodes, with the anode of the diode electrically connected to the electronic device and the cathode of the diode electrically connected to ground; or, the diode module 11 includes a first diode D1 to an Nth diode connected in series, with the cathode of the first diode D1 grounded, the anode of the Nth diode electrically connected to the electronic device, and the anode of the (n-1)th diode connected to the cathode of the nth diode; where N is a positive integer greater than or equal to 2, and n is a positive integer greater than 1 and less than or equal to N. It is understood that the diode module 11 can be configured with one or more diodes depending on the actual detection requirements. When the diode module 11 uses only one diode, the anode of that diode is electrically connected to the input terminal of the electronic device and the signal conditioning circuit 20, and the cathode is grounded. When the diode module 11 uses multiple diodes, the diodes need to be connected in series. It is understood that the state detection circuit proposed in this application is applied to the detection of low-power electronic devices. Therefore, the operating current of electronic devices is generally below 1mA. Utilizing the characteristic that the diode voltage drop increases proportionally to the current within 1mA, meaning that when there is no current in the electronic device, the initial output voltage signal is 0V, approximately 0.2V at 100uA, and approximately 0.7V at 1mA. When two diode modules 11 are used, and a parallel resistor shares part of the current, a voltage change of 0.1V-1.4V will occur between 30-200uA. Therefore, using a data acquisition circuit 10 including diode module 11 to detect the current of the electronic device can obtain a more accurate detection signal.

[0050] Optionally, N is 2, and the diode module 11 includes a first diode D1, a second diode D2, and a first resistor R1; wherein, the anode of the first diode D1 is electrically connected to the electronic device, the first terminal of the first resistor R1, and the input terminal of the signal conditioning circuit 20, and the cathode of the first diode D1 is electrically connected to the anode of the second diode D2; the cathode of the second diode D2 is electrically connected to the second terminal of the first resistor R1 and the ground terminal.

[0051] In this embodiment, the signal conditioning circuit 20 can be implemented using a corresponding signal amplification circuit 21 and a filtering circuit. The signal amplification circuit 21 can be implemented using a common-emitter amplifier circuit, an operational amplifier circuit, etc.; the filtering circuit can be implemented using a low-pass filter circuit, a band-pass filter circuit, etc. Further, the signal conditioning circuit 20 includes a signal amplification circuit 21. The input terminal of the signal amplification circuit 21 is electrically connected to the output terminal of the acquisition circuit 10, and the output terminal of the signal amplification circuit 21 is electrically connected to the control circuit 30. The signal amplification circuit 21 is used to receive the first voltage signal and output an amplified detection signal after signal amplification processing. The signal amplification circuit 21 is a non-inverting amplifier circuit. Through correlation settings with the control circuit 30, it amplifies the first voltage signal output by the acquisition circuit 10 to a corresponding voltage value, so that when the control circuit 30 receives the voltage signal, it can confirm the operating status of the electronic device. Optionally, the signal amplification circuit 21 includes a second resistor R2, a third resistor R3, and an operational amplifier OPA; wherein, the first end of the second resistor R2 is electrically connected to the ground terminal, and the second end of the second resistor R2 is electrically connected to the inverting input terminal of the operational amplifier and the first end of the second resistor R2; the second end of the third resistor R3 is electrically connected to the output terminal of the operational amplifier OPA and the control circuit 30; and the non-inverting input terminal of the operational amplifier OPA is electrically connected to the output terminal of the acquisition circuit 10.

[0052] In this embodiment, the control circuit 30 can be implemented using an FPGA (Field Programmable Gate Array), PLC (Programmable Logic Controller), MCU (Microcontroller Unit), DSP (Digital Signal Processor), or SOC (System on Chip). The conditioning detection signal is a corresponding level signal, allowing the control circuit 30 to quickly confirm the operating status of the electronic device upon receiving the conditioning detection signal output by the conditioning detection circuit. For example, when the control circuit 30 receives a low-level signal, it can confirm that the electronic device is offline; when it receives a high-level signal, it can confirm that the electronic device is online.

[0053] By employing a state detection circuit, the detection accuracy of the electronic devices within the battery management system can be effectively improved. The state detection circuit includes a data acquisition circuit 10, a signal conditioning circuit 20, and a control circuit 30. The data acquisition circuit 10 includes a diode module 11 connected in series in the electrical circuit between the electronic device and the power supply. The anode of the diode module 11 is electrically connected to the data acquisition circuit 10, and the cathode of the diode module 11 is grounded, thereby acquiring the current of the electronic device and outputting a corresponding first voltage signal through the anode of the diode module 11. Furthermore, the signal conditioning circuit 20 conditions the input first voltage signal, thereby outputting a conditioned detection signal so that the control circuit 30 can accurately obtain the operating state of the electronic device. By utilizing the characteristics of the diode module 11, the current of the electronic device can be obtained more accurately. Therefore, the detection accuracy of the electronic devices within the battery management system can be effectively improved.

[0054] refer to Fig. 2 and Fig. 3 In one embodiment of this utility model, the signal conditioning circuit 20 further includes:

[0055] The first filtering circuit 22 has its input terminal electrically connected to the output terminal of the acquisition circuit 10, and its output terminal electrically connected to the input terminal of the signal amplification circuit 21. The first filtering circuit 22 is used to receive the first voltage signal output by the first filtering circuit 22 and output it after filtering.

[0056] The second filter circuit 23 has its input terminal electrically connected to the output terminal of the signal amplification circuit 21, and its output terminal electrically connected to the control circuit 30. The second filter circuit 23 is used to receive the amplified detection signal output by the signal amplification circuit 21, and output a conditioned detection signal after filtering.

[0057] In this embodiment, both the first filter circuit 22 and the second filter circuit 23 are implemented using low-pass filter circuits. This is because the object acquired by the acquisition circuit 10 is a low-power electronic device with a small resting current. Therefore, a low-pass filter circuit is needed to filter out high-frequency noise to obtain a more accurate detection signal. Furthermore, after the first voltage signal is filtered by the first filter circuit 22, it is input to the signal amplification circuit 21. After being amplified by the signal amplification circuit 21, the amplified detection signal is output to the second filter circuit 23. After filtering by the second filter circuit 23, the conditioned detection signal is output to the control circuit 30. It is understood that the first filter circuit 22 and the second filter circuit 23 can effectively improve the accuracy of the signal input to the control circuit 30, thereby reducing the probability of misjudgment by the control circuit 30.

[0058] Optionally, the first filter circuit 22 includes a fourth resistor R4 and a first capacitor C1;

[0059] The first end of the fourth resistor R4 is electrically connected to the output end of the acquisition circuit 10, and the second end of the fourth resistor R4 is electrically connected to the first end of the first capacitor C1 and the input end of the signal amplification circuit 21; the second end of the first capacitor C1 is electrically connected to the ground end.

[0060] The second filter circuit 23 includes a fifth resistor R5 and a second capacitor C2;

[0061] The first end of the fifth resistor R5 is electrically connected to the output end of the signal amplification circuit 21, the second end of the fifth resistor R5 is electrically connected to the first end of the second capacitor C2 and the control circuit 30; the second end of the second capacitor C2 is electrically connected to the ground terminal.

[0062] This utility model also proposes a battery management system, which includes electronic equipment and a state detection circuit as described in any of the above claims. It is worth noting that since the battery management system of this utility model is based on the aforementioned state detection circuit, the embodiments of the battery management system of this utility model include all the technical solutions of all embodiments of the aforementioned state detection circuit, and the achieved technical effects are exactly the same, and will not be repeated here.

[0063] This utility model also proposes a battery pack, wherein the battery includes the battery management system as described above. It is worth noting that since the battery pack of this utility model is based on the aforementioned battery management system, the embodiments of the battery pack of this utility model include all the technical solutions of all embodiments of the aforementioned battery management system, and the achieved technical effects are exactly the same, and will not be repeated here.

[0064] The above description is merely an exemplary embodiment of the present utility model and does not limit the patent scope of the present utility model. Any equivalent structural transformations made based on the technical concept of the present utility model and the contents of the present utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present utility model.

Claims

1. A state detection circuit, applied in a battery management system, characterized in that, The battery management system includes electronic devices; the state detection circuit includes: A data acquisition circuit is connected in series in the electrical circuit between the electronic device and the power supply terminal; the data acquisition circuit includes a diode module, the anode of the diode module is electrically connected to the data acquisition circuit, and the cathode of the diode module is grounded; The acquisition circuit is used to acquire the current of the electronic device and output a corresponding first voltage signal through the anode of the diode module; A signal conditioning circuit, wherein the input terminal of the signal conditioning circuit is electrically connected to the anode of the diode module; the signal conditioning circuit is used to output a conditioning detection signal after the first voltage signal is conditioned. A control circuit is electrically connected to the output terminal of the signal conditioning circuit; the control circuit is used to receive the conditioning detection signal output by the signal conditioning circuit to confirm the working status of the electronic device.

2. The state detection circuit as described in claim 1, characterized in that, The diode module includes a diode, the anode of which is electrically connected to the electronic device, and the cathode of which is electrically connected to ground; or, The diode module includes a first diode to an Nth diode connected in series. The cathode of the first diode is grounded, the anode of the Nth diode is electrically connected to an electronic device, and the anode of the (n-1)th diode is connected to the cathode of the nth diode. Wherein, N is a positive integer greater than or equal to 2, and n is a positive integer greater than 1 and less than or equal to N.

3. The state detection circuit as described in claim 2, characterized in that, N is 2, and the diode module includes a first diode, a second diode, and a first resistor; The anode of the first diode is electrically connected to the electronic device, the first terminal of the first resistor, and the input terminal of the signal conditioning circuit; the cathode of the first diode is electrically connected to the anode of the second diode; and the cathode of the second diode is electrically connected to the second terminal of the first resistor and the ground terminal.

4. The state detection circuit as described in claim 1, characterized in that, The signal conditioning circuit includes a signal amplification circuit. The input terminal of the signal amplification circuit is electrically connected to the output terminal of the acquisition circuit, and the output terminal of the signal amplification circuit is electrically connected to the control circuit. The signal amplification circuit is used to receive the first voltage signal and output an amplified detection signal after amplifying the first voltage signal.

5. The state detection circuit as described in claim 4, characterized in that, The signal amplification circuit includes a second resistor, a third resistor, and an operational amplifier; Wherein, the first end of the second resistor is electrically connected to the ground terminal, the second end of the second resistor is electrically connected to the inverting input terminal of the operational amplifier and the first end of the second resistor; the second end of the third resistor is electrically connected to the output terminal of the operational amplifier and the control circuit; the non-inverting input terminal of the operational amplifier is electrically connected to the output terminal of the acquisition circuit.

6. The state detection circuit as described in claim 4, characterized in that, The signal conditioning circuit further includes: A first filtering circuit, wherein the input terminal of the first filtering circuit is electrically connected to the output terminal of the acquisition circuit, and the output terminal of the first filtering circuit is electrically connected to the input terminal of the signal amplification circuit; the first filtering circuit is used to receive the first voltage signal output by the first filtering circuit, and output it after filtering. The second filter circuit has its input terminal electrically connected to the output terminal of the signal amplification circuit, and its output terminal electrically connected to the control circuit. The second filter circuit is used to receive the amplified detection signal output by the signal amplification circuit, and output a conditioned detection signal after filtering.

7. The state detection circuit as described in claim 6, characterized in that, The first filter circuit includes a fourth resistor and a first capacitor; The first end of the fourth resistor is electrically connected to the output end of the acquisition circuit, and the second end of the fourth resistor is electrically connected to the first end of the first capacitor and the input end of the signal amplification circuit; the second end of the first capacitor is electrically connected to the ground terminal.

8. The state detection circuit as described in claim 6, characterized in that, The second filter circuit includes a fifth resistor and a second capacitor; The first end of the fifth resistor is electrically connected to the output end of the signal amplification circuit, and the second end of the fifth resistor is electrically connected to the first end of the second capacitor and the control circuit; the second end of the second capacitor is electrically connected to the ground terminal.

9. A battery management system, characterized in that, The battery management system includes electronic devices and a state detection circuit as described in any one of claims 1 to 8.

10. A battery pack, characterized in that, The battery includes the battery management system as described in claim 9.

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