A BMS power supply system

Abstract

The present invention relates to the field of battery management, and particularly to a BMS power supply system; the BMS power supply system includes a first switch, a DC / DC unit, a first diode, a first power supply, and a standby power supply for supplying power to external devices, wherein the output voltage of the DC / DC unit is higher than the output voltage of the first power supply; the present invention designs a BMS power supply system with a dual LDO power supply + DC / DC unit, sets the standby power supply inside the BMS system, and in the sleep state of the BMS system, the standby power supply is powered by the electric energy provided by the first power supply. In the operating state of the BMS system, the standby power supply will automatically switch to the power supply circuit of the DC / DC unit by utilizing the one-way conduction characteristic of the second diode and complete the power supply through the electric energy provided by the DC / DC unit. The standby power supply utilizes the original front-end power supply of the BMS power supply system for power supply. On the premise that the standby power supply meets the functional requirements, the circuit structure is greatly simplified, the hardware cost is reduced, and the utilization efficiency of the power supply is improved.

Description

Technical Field

[0001] The present invention relates to the field of battery management, and particularly to a BMS power supply system. Background Art

[0002] In order to meet the functional requirements of a standby power supply, the conventional standby power supply solutions on the market need to adopt expensive hardware and complex peripheral circuits; there is a lack of solutions with low cost and simple circuits. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a BMS power supply system to overcome the defects in the prior art that all functional requirements cannot be met and expensive hardware and complex peripheral circuits need to be adopted.

[0004] The technical solution adopted by the present invention to solve its technical problems is: providing a BMS power supply system, preferably: the BMS power supply system includes a first switch, a DC / DC unit, a first diode, a first power supply, and a standby power supply for supplying power to external devices. The first switch is connected to the positive electrode of the battery pack. The input end of the DC / DC unit is connected to the first switch. The output end of the DC / DC unit is connected to the positive electrode of the first diode. The negative electrode of the first diode is connected to the first input end of the standby power supply for supplying power to the standby power supply in the BMS sleep state. The input end of the first power supply is connected to the positive electrode of the battery pack. The output end of the first power supply is connected to the second input end of the standby power supply for supplying power to the standby power supply in the BMS operating state. Wherein, the output voltage of the DC / DC unit is higher than the output voltage of the first power supply.

[0005] Wherein, a preferred solution is: the standby power supply includes a second switch and a second power supply. The first input end of the second switch is used as the first input end of the standby power supply and is connected to the negative electrode of the first diode. The second input end of the second switch is used as the second input end of the standby power supply and is connected to the first power supply. The input end of the second power supply is connected to the second switch. The output end of the second power supply is used to be connected to external devices.

[0006] Wherein, a preferred solution is: the second power supply includes a current limiting unit, a Darlington tube, a feedback unit, and a voltage output port. The input end of the current limiting unit is connected to the second switch to limit the maximum operating current. The first input end of the Darlington tube is connected to the output end of the current limiting unit to control the output current. The voltage output port is connected to the output end of the Darlington tube to supply power to external devices. The input end of the feedback unit is connected to the output end of the amplification unit. The output end of the feedback unit is connected to the second input end of the Darlington tube for voltage stabilization.

[0007] Among them, a preferred solution is that the second power supply is further provided with a second diode and a precision resistor with a voltage acquisition interface. The positive electrode of the second diode is connected to the output end of the Darlington tube for high-voltage protection. The input end of the precision resistor is connected to the negative electrode of the second diode, and the first output end of the precision resistor is connected to the voltage output port for acquiring the output voltage.

[0008] Among them, a preferred solution is that the second power supply is further provided with a comparator circuit and an interrupt response circuit. The input end of the comparator circuit is connected to the second output end of the precision resistor unit. The output end of the comparator circuit is used to be connected to the BMS system and can wake up the BMS system by inserting a load when the BMS system is in sleep. The input end of the interrupt response circuit is connected to the third output end of the precision resistor unit. The output end of the interrupt response circuit is connected to the BMS system and can wake up the BMS system when the BMS system is in sleep and the standing power supply is overcurrent or short-circuited.

[0009] Among them, a preferred solution is that the feedback unit includes a feedback circuit and a voltage stabilizing circuit. The input end of the feedback circuit is connected to the first output end of the precision resistor. The output end of the feedback circuit is connected to the input end of the voltage stabilizing circuit. The output end of the voltage stabilizing circuit is connected to the second input end of the Darlington tube for adjusting the output voltage.

[0010] Among them, a preferred solution is that the second power supply further includes a TVS unit for anti-static input. The input end of the TVS unit is connected to the first output end of the precision resistor. The output end of the TVS unit is connected to the input end of the voltage stabilizing circuit for anti-static protection of the standing voltage.

[0011] Among them, a preferred solution is that a plurality of filter capacitors are connected in parallel between the TVS unit and the feedback unit for filtering.

[0012] Among them, a preferred solution is that the BMS power supply system is further provided with a third power supply for supplying power to the BMS system main controller. The input end of the third power supply is connected to the output end of the first power supply. The output end of the third power supply is connected to the BMS system main controller for power supply.

[0013] Among them, a preferred solution is that the BMS power supply system is further provided with a fourth power supply. The input end of the fourth power supply is connected to the output end of the DC / DC unit. The output end of the fourth power supply is connected to the BMS system for supplying power to the BMS system.

[0014] The beneficial effects of the present invention are as follows. Compared with the prior art, the present invention designs a BMS power supply system that combines a dual LDO power supply and a DC / DC unit. The standby power supply is arranged inside the BMS system. In the sleep state of the BMS system, the standby power supply is powered by the electric energy provided by the first power LDO1. In the operating state of the BMS system, the standby power supply will automatically switch to the power supply circuit of the DC / DC unit by using the one-way conduction characteristic of the second diode, and complete the power supply through the electric energy provided by the DC / DC unit. The standby power supply uses the original front-end power supply of the BMS power supply system for power supply. On the premise that the standby power supply meets the functional requirements of each function, the circuit structure is greatly simplified, the hardware cost is reduced, and the utilization efficiency of the power supply is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention will be further described below in conjunction with the drawings and embodiments. In the drawings:

[0016] Figure 1 is a schematic structural diagram of a BMS power supply system in the present invention;

[0017] Figure 2 is a schematic structural diagram of the standby power supply in the present invention;

[0018] Figure 3 is a circuit diagram of the standby power supply in the present invention;

[0019] Figure 4 is a circuit diagram of the comparator circuit in the present invention;

[0020] Figure 5 is a circuit diagram of the first power supply in the present invention;

[0021] Figure 6 is a working flow chart of the standby power supply in the BMS operating state in the present invention;

[0022] Figure 7 is a working flow chart of the standby power supply in the BMS sleep state in the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] The preferred embodiments of the present invention will be described in detail below in conjunction with the drawings.

[0024] As Figure 1 shown, the present invention provides a preferred embodiment of a BMS power supply system.

[0025] A BMS power supply system, referring to Figure 1, the BMS power supply system includes a first switch SW1, a DC / DC unit, a first diode D1, a first power supply LDO1, and a standby power supply 1 for supplying power to external devices. The first switch SW1 is connected to the positive electrode B+ of the battery pack. The input end of the DC / DC unit is connected to the first switch SW1. The output end of the DC / DC unit is connected to the positive electrode of the first diode D1. The negative electrode of the first diode D1 is connected to the first input end of the standby power supply 1 for supplying power to the standby power supply 1 in the BMS sleep state. The input end of the first power supply LDO1 is connected to the positive electrode B+ of the battery pack. The output end of the first power supply LDO1 is connected to the second input end of the standby power supply 1 for supplying power to the standby power supply 1 in the BMS operating state. Wherein, the output voltage of the DC / DC unit is higher than the output voltage of the first power supply LDO1.

[0026] Specifically, the BMS power supply system mainly includes two parts of power supply circuits. The first circuit includes the first switch SW1, the DC / DC unit, the first diode D1, and the standby power supply 1. This circuit mainly realizes the power supply of the standby power supply 1 in the BMS operating state. The second circuit includes the first power supply LDO1 and the standby power supply 1. This circuit mainly realizes the power supply of the standby power supply 1 in the BMS sleep state. Wherein, the output voltage of the DC / DC unit is higher than the output voltage of the first power supply LDO1. When the first switch SW1 is closed, the standby power supply 1 will be powered through the second power supply. When the first switch SW1 is opened, due to the output voltage of the DC / DC unit being higher than the output voltage of the first power supply LDO1, and the first diode D1 having the characteristic of unidirectional conduction, the standby power supply 1 will be powered through the first circuit. In this way, the first circuit and the second circuit can achieve automatic switching to meet the power supply of the standby power supply 1 in different states of the BMS system.

[0027] In this embodiment, by arranging the standby power supply 1 inside the BMS power supply system, in the BMS sleep state, the standby power supply 1 is powered by the electric energy provided by the first power supply LDO1. In the BMS operating state, the standby power supply 1 will switch to the electric energy provided by the DC / DC unit to complete the power supply. This setting utilizes the original front-end power supply of the BMS power supply system for power supply, greatly simplifies the circuit structure, reduces the hardware cost, and improves the utilization efficiency of the power supply.

[0028] Among them, the standby power supply 1 is mainly used to supply power to the external application product 10. For example, the standby power supply 1 can be connected to an electric bicycle to supply power to the acceleration sensor after power failure, so that the main control part of the electric bicycle can still use motion to wake up the BMS system or activate the BMS system when in a dormant or power-off state; the standby power supply 1 can also be connected to an electric boat to supply power to the handle controller, so that the handle controller can still work when the BMS system is dormant and wake up the BMS system through communication. The first switch SW1 is used to control the on / off circuit of the DC / DC unit. The input end of the first switch SW1 is connected to the total positive pole of the BMS battery pack to obtain electric energy, and the output end of the first switch SW1 is connected to the DC / DC unit to control the on / off of the DC / DC unit circuit. The first switch SW1 can control the on / off of the DC / DC unit circuit by connecting to the BMS system master controller MCU_Power1 signal pin of the BMS system master controller MCU. The BMS system master controller MCU_Power1 signal pin is specifically a general I / O port of the BMS system master controller MCU. The input end of the DC / DC unit is connected to the first switch SW1, and its output end is connected to the positive pole of the first diode D1. The DC / DC unit is mainly used as the power supply for the first circuit. The positive pole of the first diode D1 is connected to the output end of the DC / DC unit, and the negative pole of the first diode D1 is connected to the first input end of the standby power supply 1. It is mainly used to cooperate with the DC / DC unit and the first power supply LDO1 to realize the automatic switching between the first circuit and the second circuit. The input end of the first power supply LDO1 is connected to the total positive pole of the BMS battery pack to obtain electric energy, and the output end of the first power supply LDO1 is connected to the second input end of the standby power supply 1. It is mainly used to supply power to the standby power supply 1 in the BMS sleep state.

[0029] Among them, the BMS power supply system is also provided with a third power supply LDO3 for supplying power to the BMS system master controller MCU. The input end of the third power supply LDO3 is connected to the output end of the first power supply LDO1, and the output end of the third power supply LDO3 is connected to the BMS system master controller MCU for power supply.

[0030] Among them, the BMS power supply system is also provided with a fourth power supply LDO4. The input end of the fourth power supply LDO4 is connected to the output end of the DC / DC unit, and the output end of the fourth power supply LDO4 is connected to the BMS system for supplying power to the BMS system. The fourth power supply LDO4 is mainly used to supply power to the part of the BMS system other than the BMS system master controller MCU, and it can only work when the BMS system is in an operating state.

[0031] Such as Figures 1-4As shown, the present invention provides an optimal embodiment of a standby power supply.

[0032] Referring to Figure 1 , the standby power supply 1 includes a second switch SW2 and a second power supply LDO2. The first input terminal of the second switch SW2 serves as the first input terminal of the standby power supply 1 and is connected to the negative electrode of the first diode D1. The second input terminal of the second switch SW2 serves as the second input terminal of the standby power supply 1 and is connected to the first power supply LDO1. The input terminal of the second power supply LDO2 is connected to the second switch SW2, and the output terminal of the second power supply LDO2 is used to connect to an external device.

[0033] Specifically, and referring to Figure 1 and Figure 2 , the second switch SW2 includes two power input terminals, namely the first input terminal of the second switch SW2 and the second input terminal of the second switch SW2. The first input terminal of the second switch SW2 is connected to the negative electrode of the first diode D1 to serve as the first input terminal of the common power supply and obtain the electric energy provided by the first circuit. The second input terminal of the second switch SW2 is connected to the output terminal of the first power supply LDO1 to serve as the second input terminal of the standby power supply 1 and obtain the electric energy provided by the second circuit. The second switch SW2 is mainly used to control the on / off of the second power supply LDO2. The second switch SW2 can control the on / off of the second power supply LDO2 by connecting to the BMS system master controller MCU_Power1 signal pin of the BMS system master controller MCU. The BMS system master controller MCU_Power1 signal pin is specifically a general I / O port of the BMS system master controller MCU.

[0034] Among them, and referring to Figure 3 , a MOS transistor Q4, a MOS transistor Q5, a resistor R9 connected in series between the MOS transistor Q4 and the MOS transistor Q5, a resistor R11 connected in parallel with the MOS transistor Q5, a resistor R8 connected in parallel with the MOS transistor Q4, and a zener diode ZD1 are provided in the circuit of the second switch SW2; among them, when the +5VCON at the signal input terminal is at a high level, both the MOS transistor Q4 and the MOS transistor Q5 are turned on, and the standby power supply 1 is in an on state; when the +5VCON at the signal input terminal is cleared, both the MOS transistor Q4 and the MOS transistor Q5 are turned off, and the standby power supply 1 is in an off state. To meet the low-power requirement of the BMS system, the resistors R8, R9, and R11 in the second switch SW2 circuit are all set to high resistance values. Among them, the MOS transistor Q4 is a PMOS transistor, and the MOS transistor Q5 is an NMOS transistor.

[0035] Furthermore, and referring to Figure 2, the second power supply LDO2 includes a current limiting unit 20, a Darlington transistor 30, a feedback unit, and a voltage output port 2. The input end of the current limiting unit 20 is connected to the second switch SW2 to limit the maximum operating current. The first input end of the Darlington transistor 30 is connected to the output end of the current limiting unit 20 to control the output current. The voltage output port 2 is connected to the output end of the Darlington transistor 30 to supply power to an external device. The input end of the feedback unit is connected to the output end of the Darlington transistor 30, and the output end of the feedback unit is connected to the second input end of the Darlington transistor 30 for voltage regulation.

[0036] Specifically, with reference to Figure 3 , the input end of the current limiting unit 20 is connected to the second switch SW2, the output end of the current limiting unit 20 is connected to the input end of the Darlington transistor 30. The circuit of the current limiting unit 20 mainly includes a reference voltage chip U1, a precision resistor R2, and a precision resistor R3. The resistance values of the precision resistor R2 and the precision resistor R3 are the same. The current limiting unit 20 can limit the current flowing through the precision resistor R2 and the precision resistor R3 through the reference voltage at its R end and A end to limit the maximum operating current of the standby power supply 1. The first input end of the Darlington transistor 30 is connected to the output of the current limiting unit 20. The circuit of the Darlington transistor 30 mainly includes a triode Q2, a triode Q3, a resistor R4, and a resistor R5. The triode Q2 and the triode Q3 form the amplification structure of the Darlington transistor 30. The resistor R5 controls the current flowing through the base of the triode Q2, the resistor R4 controls the current flowing through the collector of the triode Q2, and the resistor R4 and the resistor R5 jointly control the base current of the triode Q3, thereby indirectly controlling the output current magnitude of the standby power supply 1.

[0037] Furthermore, with reference to Figure 2 , the input end of the feedback unit is connected to the output end of the Darlington transistor 30, the output end of the feedback unit is connected to the second input end of the Darlington transistor 30. The feedback unit is mainly used to feedback the output voltage and adjust the output voltage to maintain the stability of the output voltage. The feedback unit includes a feedback circuit 80 and a voltage regulating circuit 70. The input end of the feedback circuit 80 is connected to the first output end of the precision resistor, the output end of the feedback circuit 80 is connected to the input end of the voltage regulating circuit 70, and the output end of the voltage regulating circuit 70 is connected to the second input end of the Darlington transistor 30.

[0038] Specifically, with reference to Figure 3, the feedback circuit 80 mainly includes a series-connected resistor R6 and resistor R7. The resistor R6 and the resistor R7 form a series voltage division circuit and feedback the output voltage. The voltage regulation circuit 70 mainly includes a reference voltage chip U2. The reference voltage chip U2 can adjust the output voltage in real time to maintain the stability of the voltage. A capacitor C1 is provided between the K terminal and the R terminal of the reference voltage chip U2. The capacitor C1 is mainly used to accelerate the response of the feedback signal, so that the output voltage can be adjusted more quickly. The voltage output port 2 is mainly used to connect to an external application product 10 for supplying power to the external application product 10.

[0039] Further, with reference to Figure 2 , the second power supply LDO2 is also provided with a second diode D2 and a precision resistor 40 provided with a voltage acquisition interface. The positive electrode of the second diode D2 is connected to the output end of the Darlington tube 30 for high-voltage protection. The input end of the precision resistor 40 is connected to the negative electrode of the second diode D2. The first output end of the precision resistor 40 is connected to the voltage output port 2 for acquiring the output voltage.

[0040] Specifically, with reference to Figure 3 , the second diode D2 is a Schottky diode with a low forward voltage drop and a large overcurrent. It is used to prevent damage to electronic devices caused by high-voltage input, thereby protecting the triode Q2 and triode Q3 in the Darlington tube 30 circuit and the reference voltage chip U2 in the voltage regulation circuit 70. The precision resistor 40 is mainly used to connect to different logic function pins of the BMS system master controller MCU to implement multiple different functions, so as to realize the function expansion of the BMS power supply system. It should be noted that the addition of the second diode D2 and the precision resistor 40 will not affect the output voltage of the standby power supply 1, and the function expansion of the BMS power supply system can be realized without sacrificing the output voltage. This is the main function of setting the second diode D2 and the precision resistor. In this embodiment, the second power supply LDO2 is provided with two precision resistors, namely precision resistor R12 and precision resistor R13, and the precision resistor R12 and the precision resistor R13 are in parallel. Voltage acquisition interfaces are respectively provided at both ends of the precision resistor R12 and the precision resistor R13, namely voltage acquisition interface +5VCheck1 and voltage acquisition interface +5VCheck2. Both the voltage acquisition interface +5VCheck1 and the voltage acquisition interface +5VCheck2 can be connected to the pins of the BMS system master controller MCU that support both ADC and external interrupt functions at the same time for acquiring the output voltage and other extended functions.

[0041] Among them, the standby power supply 1 uses the Darlington tube 30 with a double triode structure to amplify the output current step by step. The reference voltage chip U2 uses the output terminal feedback signal to respond in real time to accurately adjust the output voltage to maintain the stability of the output voltage and achieve the voltage stabilization function. The precision resistor R12, precision resistor R13, and second diode D2 at the front end of the voltage output port 2 are the core parts of the standby power supply 1. They are at the front end of the output feedback resistor R6 and output feedback resistor R7 and will not affect the output voltage value. The voltage value and current value on the precision resistor R12, precision resistor R13, and second diode D2 are all changing in real time, and the precision resistor R12 and precision resistor R13 can expand the function of the standby power supply by adding an auxiliary circuit.

[0042] Further, with reference to Figure 2 , the second power supply LDO2 is also provided with a comparator circuit 50 and an interrupt response circuit 60. The input end of the comparator circuit 50 is connected to the second output end of the precision resistor. The output end of the comparator circuit 50 is used to be connected to the BMS system and can insert a load to wake up the BMS system when the BMS system is in sleep. The input end of the interrupt response circuit 60 is connected to the third output end of the precision resistor. The output end of the interrupt response circuit 60 is connected to the BMS system and can wake up the BMS system when the BMS system is in sleep and the standby power supply 1 is overcurrent or short-circuited.

[0043] Specifically, with reference to Figure 2 and Figure 3 , the comparator circuit 50 and the interrupt response circuit 60 are mainly used to cooperate with the precision resistor R12 and the precision resistor R13 to achieve multiple extended functions. It can mainly achieve three functions. The first is that through the cooperation of the comparator circuit 50 with the precision resistor R12 and the precision resistor R13, the function of inserting a load to wake up the BMS system when the BMS system is in sleep can be realized; the second is that through the cooperation of the interrupt response circuit 60 with the precision resistor R12 and the precision resistor R13, the output voltage of the du'an can be detected and the output current can be calculated to judge the working state of the power supply to achieve timely protection of the power supply; the third is that through the cooperation of the interrupt response circuit 60 with the precision resistor R12 and the precision resistor R13, when the BMS system is in sleep and the standby power supply 1 is overcurrent or short-circuited, it can be connected to the BMS system main controller MCU and wake up the BMS system through the external interrupt of the BMS system main controller MCU voltage acquisition interface.

[0044] Among them, with reference to Figure 2 and Figure 3, the interruption response circuit 60 includes a first interruption circuit disposed between the precision resistor R12 and the voltage acquisition interface +5VCheck1, and a second interruption circuit disposed between the precision resistor R12 and the voltage acquisition interface +5VCheck2. The first interruption circuit includes a voltage dividing resistor R16 and a voltage dividing resistor R17 at the input end, and also includes a filtering capacitor C7 and a voltage stabilizing diode ZD3 at the input end. The second interruption circuit includes a voltage dividing resistor R14 and a voltage dividing resistor R15 at the input end, and also includes a filtering capacitor C8 and a voltage stabilizing diode ZD2 at the input end. The voltage dividing resistors R14, R15, R16, and R17 are all voltage dividing resistors at the input end, mainly used to convert the input voltage into a range that can be acquired by the main controller MCU of the BMS system. Moreover, considering the power consumption savings of the standby power supply 1, their resistance values should be taken as large as possible. The filtering capacitor C7 and the filtering capacitor C8 are both input filtering capacitors, used to filter out jitter and interference. The voltage stabilizing diodes ZD2 and ZD3 are both used to protect the safety of the input port of the main controller MCU of the BMS system. The input port circuit of the main controller MCU of the BMS system also supports protection against high-voltage intrusion and electrostatic breakdown.

[0045] Among them, with reference to Figures 2-4, the input terminal of the comparator circuit 50 is connected to the precision resistor R12, the output terminal of the comparator circuit 50 is the 5VPowerActivation interface, and the 5VPowerActivation interface can be connected to the external interrupt port of the BMS system master controller MCU. The comparator circuit 50 further includes a comparator U3, a resistor R23, a resistor R24, a resistor R25, and a capacitor C13. Among them, R25 is a current-limiting resistor for the 5VPowerActivation interface to connect to the interrupt port of the BMS system master controller MCU. The comparator U3 is an ultra-low-power comparator U3, and its power consumption is about 300 nA during normal operation. Since it is required to work in the sleep state of the BMS system, the power supply is selected as the power supply of the BMS system master controller MCU. It can also be directly powered by the general-purpose I / O port of the BMS system master controller MCU. The comparator U3 can compare the voltages input to the positive and negative terminals of the comparator U3 across the precision resistor R12 and the precision resistor R13 according to the load current magnitude when the BMS system is in the sleep state and a load is inserted, and determine whether to wake up the BMS system based on the voltage magnitude. If the output load current makes the voltage at the positive terminal of the comparator U3 greater than the voltage at the negative terminal, the comparator U3 outputs a high level; otherwise, it outputs a low level. When the comparator U3 switches from a low level to a high level, it will trigger an interrupt on the 5VPowerActivation pin of the BMS system master controller MCU, thereby waking up the BMS system. Since when the comparator U3 switches from a low level to a high level, the voltage at the positive terminal is always greater than the voltage at the negative terminal, the resistance value of the resistor R24 should be designed to be smaller than the resistors R14 and R15 in the interrupt response circuit 60 and smaller than the resistor R23. In this way, when the load current does not exceed a certain value, the voltage at the positive terminal of the comparator U3 is still smaller than the voltage at the negative terminal. Through calculation, when the voltage difference X at both ends of the precision resistor R12 that triggers the interrupt > ((R23 - R24) / (2 * R24)) * the output voltage value of the standby power supply 1, the comparator U3 outputs a high level to trigger the interrupt. It can be seen from the formula that when the output voltage value of the standby power supply 1 becomes smaller, the voltage difference X that triggers the interrupt will become smaller. That is to say, when the BMS is short-circuited or over-current in the sleep state, the output voltage value of the standby power supply 1 becomes smaller, and the voltage across the precision resistor R12 becomes larger, which will definitely trigger the interrupt and the BMS system will also be woken up. However, within the range of the load current when the first power supply LDO1 is working normally, the output of the standby power supply 1 will be stable at 3.3V or 5V. Only when the standby power supply 1 is over-current or short-circuited, the output voltage will be pulled down to trigger the interrupt. The comparator circuit 50 can only work when the BMS system is in the sleep state.The main controller MCU of the BMS system is in a low-power state and can only process external interrupt signals. It is unable to determine the working state of the standby power supply 1. Moreover, the output current of the first power supply LDO1 is limited. Therefore, at this time, the overcurrent and short-circuit manifestations of the standby power supply 1 are the same, both of which will pull down the output voltage of the standby power supply 1 to close to zero, thereby triggering an interrupt to wake up the BMS system. The voltage acquisition interfaces +5VCheck1 and +5VCheck2 can also enable the external interrupt function. Overcurrent and short-circuit will both cause a switch from high level to low level, thereby triggering an interrupt to wake up the BMS system. Here, three BMS system main controller MCU interfaces play a role of triple-redundancy interrupt triggering to wake up the BMS system.

[0046] Furthermore, with reference to Figure 2 , the second power supply LDO2 further includes a TVS unit 90 for anti-static input. The input end of the TVS unit 90 is connected to the first output end of the precision resistor, and the output end of the TVS unit 90 is connected to the input end of the voltage regulating circuit 70 for anti-static protection of the standby voltage.

[0047] Specifically, with reference to Figure 3 , the TVS unit 90 includes a voltage stabilizing diode ZD7 and a resistor R16. The resistor R16 is connected in series with the voltage stabilizing diode ZD7. The TVS unit 90 is mainly used for anti-static input at the output interface end, thereby protecting the safety of the power supply circuit.

[0048] Furthermore, with reference to Figure 3 , a plurality of filter capacitors, namely capacitor C2, capacitor C3, and capacitor C4, are connected in parallel between the TVS unit 90 and the feedback unit. The capacitor C2, capacitor C3, and capacitor C4 are all filter capacitors at the output end of the standby power supply 1, used to filter out the interference of high-frequency and low-frequency parts in the output voltage.

[0049] As Figure 5 shown, the present invention provides an optimal embodiment of the first power supply LDO1.

[0050] Refer to Figure 5, the first power supply LDO1 is provided with an amplifying transistor Q7, an amplifying transistor Q6, a voltage stabilizing diode ZD5, a voltage stabilizing diode ZD4, a resistor R18, a resistor R19, a resistor R20, a resistor R21, a resistor R22, a capacitor C9, a capacitor C10, a capacitor C11 and a capacitor C12. The resistor R18 and the resistor R19 are series current-limiting resistors for controlling the magnitude of the output current. The resistor R20 functions to control the base current of the amplifying transistor Q7. Together with the voltage stabilizing diode ZD5 and the voltage stabilizing diode ZD4, it controls the magnitude of the output voltage. The resistor R21 functions to control the collector output current of the amplifying transistor Q7 and, together with the resistor R20, controls the base current of the amplifying transistor Q6, thereby indirectly controlling the magnitude of the output current of the first power supply LDO1. The capacitor C10, the capacitor C11 and the capacitor C12 are output filter capacitors of the first power supply LDO1. If the load current is relatively large when the main control part of the application product connected to the standby power supply 1 inserts a load in the BMS system sleep state, for example, exceeding 45 mA, the BMS system can be awakened by increasing the capacitor R18, the capacitor R19 and the capacitor R20. The comparator circuit 50 part can be omitted. By increasing the capacitor R18, the capacitor R19 and the capacitor R20, the output voltage of the first power supply LDO1 can be controlled. When the load is large, the output voltage is pulled down, causing the first power supply LDO1 part to fail to work, directly pulling the output voltage of the standby power supply 1 close to zero, thereby triggering the conversion interruption of the high level to the low level at the voltage acquisition port, and this interruption can awaken the BMS system. However, it should be noted that the resistance cannot be adjusted too large, which will cause the main controller MCU of the BMS system to stop working due to insufficient power supply.

[0051] To further explain the BMS power supply system, the present invention also provides a description of the working process of the standby power supply 1 in the BMS operating state.

[0052] Specifically, with reference to Figure 6, the standby power supply 1 can measure the output voltage according to the voltage acquisition interface +5VCheck2, and then calculate the output current I based on the voltages measured by the voltage acquisition interface +5VCheck1 and the voltage acquisition interface +5VCheck2. The calculation formula is: I = (+5VCheck1 - +5VCheck2) / the resistance value of the precision resistor at the output end. Finally, the power supply working state is judged according to the preset working process of the standby power supply 1 in the BMS system operation state. When a fault state is judged, the corresponding processing is carried out by entering the fault handling process. Three fault states of the standby power supply 1 can be preset: power supply voltage offset, power supply overcurrent, and power supply short circuit. Fault protection of the power supply will be carried out for these three fault states, and the processing processes are basically the same, only the reported fault types are different. In this embodiment, taking the standby power supply 1 outputting 5V and limiting the current to 100mA as an example, the specific working process preset for the standby power supply 1 is described in detail:

[0053] 1. When the output voltage < 4.9V or the output voltage > 5.1V and the output current ≤ 10mA, the output voltage of the standby power supply 1 is offset, a voltage offset fault alarm is issued, and the standby power supply 1 is turned off;

[0054] 2. When 4.9V ≤ output voltage ≤ 5.1V and the output current ≤ 10mA, the standby power supply 1 is in an idle state and works normally;

[0055] 3. When 4.85V ≤ output voltage ≤ 5.05V and the output current ≤ 80mA, the standby power supply 1 is in a loaded state and works normally;

[0056] 4. When 4.8V ≤ output voltage ≤ 5.0V and the output current ≤ 100mA, the standby power supply 1 is in a full-load state and works normally, but it is necessary to remind regularly that the load is too large;

[0057] 5. When 1V ≤ output voltage < 4.8V and the output current ≤ 115mA, the standby power supply 1 is in an overcurrent state, works abnormally, issues an overcurrent fault alarm, and turns off the standby power supply 1 for protection;

[0058] 6. When 0V ≤ output voltage < 1V and the output current ≤ 100mA, the standby power supply 1 is in a short-circuit state, works abnormally, issues a short-circuit fault alarm, and turns off the standby power supply 1 for protection.

[0059] To further explain the BMS power supply system, the present invention also provides a description of the working process of the standby power supply 1 after being awakened in the BMS sleep state.

[0060] Specifically, and with reference to Figure 7, in the BMS sleep state, the 5VPowerActivation interface may output a high level when overcurrent, short circuit, or load insertion occurs. The voltage acquisition interface +5VCheck1 and the voltage acquisition interface +5VCheck2 only play the role of external interruption when overcurrent or short circuit occurs. Therefore, the 5VPowerActivation interface, or the voltage acquisition interface +5VCheck1, or the voltage acquisition interface +5VCheck2 can all interrupt and wake up the BMS system. After waking up the BMS system, the DC / DC unit is turned on to supply power to the standby power supply 1. If the standby power supply 1 works normally, the process continues to monitor the working state of the standby power supply 1. If an abnormal fault occurs, the BMS system master controller MCU needs to control the shutdown of the standby power supply 1 and send a fault warning message. After the standby power supply is turned off for 30 seconds, the BMS system master controller MCU autonomously resumes the power supply of the standby power supply 1, counts the number of recoveries, and continues to monitor the working state of the standby power supply 1 that has resumed power supply. At this time, if the standby power supply 1 returns to normal, the monitoring continues; if the standby power supply 1 is abnormal, the standby power supply 1 is turned off again, and a fault warning message is sent. After repeating the recovery many times, the number of recoveries in this embodiment is three. If the standby continues to be abnormal, the BMS system master controller MCU will turn off the standby power supply 1 and lock the recovery function, and send a fault warning message. The BMS system enters the sleep state after a 2-hour delay. During this period, the standby power supply 1 can be restored to power supply by charging activation.

[0061] The above are only the best embodiments of the present invention and are not used to limit the scope of the present invention. Any equivalent changes or modifications made in accordance with the scope of the patent application of the present invention are covered by the present invention.

Claims

1. A BMS power supply system, characterized in that: The described BMS power supply system includes a first switch, a DC / DC unit, a first diode, a first power supply, and a standby power supply for powering external devices. The first switch is connected to the positive electrode of the battery pack. The input end of the DC / DC unit is connected to the first switch. The output end of the DC / DC unit is connected to the positive electrode of the first diode. The negative electrode of the first diode is connected to the first input end of the standby power supply for powering the standby power supply in the BMS operating state. The input end of the first power supply is connected to the positive electrode of the battery pack. The output end of the first power supply is connected to the second input end of the standby power supply for powering the standby power supply in the BMS sleep state. Among them, the output voltage of the DC / DC unit is higher than the output voltage of the first power supply. The standby power supply includes a second switch and a second power supply. The first input end of the second switch serves as the first input end of the standby power supply and is connected to the negative electrode of the first diode. The second input end of the second switch serves as the second input end of the standby power supply and is connected to the first power supply. The input end of the second power supply is connected to the second switch. The output end of the second power supply is used to connect to external devices. The second power supply includes a current limiting unit, a Darlington tube, a feedback unit, and a voltage output port. The input end of the current limiting unit is connected to the second switch to limit the maximum operating current. The first input end of the Darlington tube is connected to the output end of the current limiting unit to control the output current. The voltage output port is connected to the output end of the Darlington tube to power external devices. The input end of the feedback unit is connected to the output end of the amplification unit. The output end of the feedback unit is connected to the second input end of the Darlington tube for voltage stabilization.

2. The BMS power supply system according to claim 1, characterized in that: The second power supply is also provided with a second diode and a precision resistor provided with a voltage acquisition interface. The positive electrode of the second diode is connected to the output end of the Darlington tube for high-voltage protection. The input end of the precision resistor is connected to the negative electrode of the second diode. The first output end of the precision resistor is connected to the voltage output port for acquiring the output voltage.

3. The BMS power supply system according to claim 2, characterized in that: The second power supply is also provided with a comparator circuit and an interrupt response circuit. The input end of the comparator circuit is connected to the second output end of the precision resistor unit. The output end of the comparator circuit is used to connect to the BMS system and can insert a load to wake up the BMS system when the BMS system is in sleep. The input end of the interrupt response circuit is connected to the third output end of the precision resistor unit. The output end of the interrupt response circuit is connected to the BMS system and can wake up the BMS system when the BMS system is in sleep and the standby power supply is overcurrent or short-circuited.

4. The BMS power supply system according to claim 2, wherein: The feedback unit includes a feedback circuit and a voltage stabilization circuit. The input end of the feedback circuit is connected to the first output end of the precision resistor. The output end of the feedback circuit is connected to the input end of the voltage stabilization circuit. The output end of the voltage stabilization circuit is connected to the second input end of the Darlington tube for adjusting the output voltage.

5. The BMS power supply system according to claim 4, characterized in that: The second power supply further includes a TVS unit for anti-static input. The input end of the TVS unit is connected to the first output end of the precision resistor, and the output end of the TVS unit is connected to the input end of the voltage stabilizing circuit for anti-static protection of the standing voltage.

6. The BMS power supply system according to claim 5, wherein: A plurality of filter capacitors are connected in parallel between the TVS unit and the feedback unit for filtering.

7. The BMS power supply system according to claim 1, wherein: The BMS power supply system is further provided with a third power supply for supplying power to the BMS system master controller. The input end of the third power supply is connected to the output end of the first power supply, and the output end of the third power supply is connected to the BMS system master controller for power supply.

8. The BMS power supply system according to claim 1, wherein: The BMS power supply system is further provided with a fourth power supply. The input end of the fourth power supply is connected to the output end of the DC / DC unit, and the output end of the fourth power supply is connected to the BMS system for supplying power to the BMS system.

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