Rechargeable battery management circuit with load detection function

Abstract

The utility model discloses a kind of rechargeable battery management circuits with load detection function, it includes: between the power loop of connecting in the target battery of rechargeable and power equipment, charging switch and discharge switch are provided on power loop;Voltage detection circuit, it includes acquisition unit and processing unit;The input end of acquisition unit is electrically connected with the negative electrode end of power loop for with power equipment, the output of acquisition unit is electrically connected with processing unit, acquisition unit is used to generate the second voltage signal that processing unit can identify according to the first voltage signal of the negative electrode end of power equipment;Processing unit is also electrically connected with charging switch and discharge switch, for obtaining the state of first voltage signal according to second voltage signal and the circuit architecture of acquisition unit, above-mentioned management circuit can judge whether it satisfies charging requirement in time when charger is accessed, to avoid inappropriate charging behavior, significantly improve the security of battery use and battery life.

Description

Technical Field

[0001] This utility model relates to the field of rechargeable battery charge and discharge management technology, and in particular to a rechargeable battery management circuit with load detection function. Background Technology

[0002] With the widespread use of rechargeable batteries in various electronic and electric devices, the Battery Management System (BMS) plays a crucial role in the charging and discharging management of battery packs. The BMS effectively manages the charging and discharging process of the battery pack, ensuring it operates in a healthy and safe state. A BMS typically contains multiple circuit modules that work together to monitor, protect, and optimize battery status. However, to minimize the BMS's own power consumption, it is often designed to automatically enter a sleep state under certain conditions. In sleep mode, the BMS shuts down most of its circuit modules, minimizing its own power consumption and extending battery life. The BMS is then woken up when a connection is made.

[0003] Therefore, a BMS system needs to have the ability to detect external load connections, especially the ability to detect whether a charger is connected, so as to wake up the system and restore normal operation in a timely manner when a charger is connected. In existing technologies, charger connection detection is typically implemented using comparators or transistor circuits. While these solutions can detect charger connection to some extent, they have significant limitations: they cannot effectively detect the charger's voltage range, nor can they determine whether the connected charger meets the battery charging requirements. Utility Model Content

[0004] The purpose of this invention is to provide a rechargeable battery management circuit with load detection function that can accurately determine the type of load connected and whether the specifications of the connected charger meet the requirements.

[0005] To achieve the above objectives, this utility model provides a rechargeable battery management circuit with load detection function, comprising: A power circuit connecting a rechargeable target battery and a power device, the power device including a charger or load, the power circuit being provided with a charging switch and a discharging switch; A voltage detection circuit, which includes a data acquisition unit and a processing unit; The input terminal of the acquisition unit is electrically connected to the power circuit and to the negative terminal of the power device. The output of the acquisition unit is electrically connected to the processing unit. The acquisition unit is used to generate a second voltage signal that can be recognized by the processing unit based on the first voltage signal of the negative terminal of the power device. The processing unit is also electrically connected to the charging switch and the discharging switch, and is used to calculate the state of the first voltage signal based on the second voltage signal and the circuit architecture of the acquisition unit, and control the on / off state of the charging switch or the discharging switch based on the state of the first voltage signal.

[0006] Preferably, the acquisition unit includes a first switching transistor and a first voltage source; one controllable connection terminal of the first switching transistor is electrically connected to the negative terminal of the power device through a first resistor, and the other controllable connection terminal of the first switching transistor is grounded through a second resistor; the first voltage source is electrically connected to the processing unit through a third resistor, and the first voltage source is also grounded through the series connection of the third resistor and the second resistor.

[0007] Preferably, the first switching transistor includes a first MOSFET and a second MOSFET connected in series, and the body diodes in the first MOSFET and the second MOSFET have opposite bias directions.

[0008] Preferably, the gates of the first MOSFET and the second MOSFET are electrically connected to the node between the first MOSFET and the second MOSFET through a common pull-down resistor.

[0009] Preferably, the control terminal of the first switching transistor is electrically connected to the processing unit.

[0010] Preferably, the control terminal of the first switch is electrically connected to the enable terminal of the processing unit.

[0011] Preferably, the voltage detection circuit further includes a switching unit, which includes a second switching transistor, a third switching transistor, and a second voltage source. The control terminal of the second switching transistor is electrically connected to the processing unit through a voltage divider resistor circuit. One controllable connection terminal of the second switching transistor is grounded, and the other controllable connection terminal of the second switching transistor is electrically connected to the control terminal of the third switching transistor through a fourth resistor. One controllable connection terminal of the third switching transistor is electrically connected to the second voltage source, and the other controllable connection terminal of the third switching transistor is electrically connected to the control terminal of the first switching transistor through a fifth resistor.

[0012] Preferably, both the second and third switching transistors are bipolar transistors.

[0013] Preferably, the voltage divider resistor circuit includes a sixth resistor and a seventh resistor, the sixth resistor being disposed between the control terminal of the second switching transistor and the processing unit, and the seventh resistor being disposed between the control terminal of the second switching transistor and the ground terminal.

[0014] Preferably, the device further includes a battery status acquisition device, one end of which is electrically connected to each battery cell in the target battery to acquire the voltage and / or temperature of each battery cell, and the other end of which is electrically connected to the processing unit. The processing unit also controls the state of the charging switch or the discharging switch based on the parameters acquired by the battery status acquisition device.

[0015] Compared to existing technologies, the rechargeable battery management circuit provided by the above technical solution includes a voltage detection circuit. This circuit acquires a first voltage signal from the negative terminal of the power device through a data acquisition unit and converts it into a second voltage signal that can be recognized by a processing unit. The processing unit calculates the state (e.g., positive / negative value and magnitude) of the first voltage signal based on the second voltage signal and the circuit architecture of the data acquisition unit. Furthermore, by analyzing the state of the first voltage signal, it can accurately distinguish whether the currently connected load is a charger or a regular load. Moreover, if a charger is identified, the magnitude of the calculated first voltage signal can further determine whether the charger's voltage is within a safe range. Therefore, the above management circuit can promptly determine whether a charger meets charging requirements when connected, thereby avoiding inappropriate charging behavior and significantly improving battery safety and lifespan. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the rechargeable battery management circuit in an embodiment of this utility model.

[0017] Figure 2 for Figure 1 The circuit schematic of the data acquisition unit. Detailed Implementation

[0018] To explain in detail the technical content, structural features, objectives and effects of this utility model, the following description is provided in conjunction with the embodiments and accompanying drawings.

[0019] This embodiment discloses a rechargeable battery management circuit with load detection function, which is suitable for managing the charging and discharging of a rechargeable target battery and can accurately identify the load type and determine whether the charger voltage meets the requirements.

[0020] like Figure 1 The battery management circuit in this embodiment mainly includes the following parts: Power circuit L: This circuit connects the rechargeable target battery to the power device, which can be a charger or a load. A charging switch K1 and a discharging switch K2 are connected in series in power circuit L to control the on / off state of the charging and discharging processes, respectively. The charging switch K1 and discharging switch K2 can be implemented using MOSFETs or other suitable electronic switching devices.

[0021] Voltage detection circuit: This circuit includes an acquisition unit 100 and a processing unit MCU, which is used to detect the voltage signal at the negative terminal C- of the power device and perform analysis and processing.

[0022] Acquisition unit 100: Its input terminal is electrically connected to the negative terminal C- of the power supply circuit L, used for connecting power devices, and is used to acquire the voltage signal (i.e., the first voltage signal) of the negative terminal C-. Acquisition unit 100 may include a voltage divider resistor network, an operational amplifier, or other signal conditioning circuits to convert the first voltage signal into a second voltage signal suitable for processing. The output terminal of acquisition unit 100 is electrically connected to the processing unit MCU, transmitting the second voltage signal to the processing unit MCU.

[0023] The processing unit MCU, which can be a microcontroller or an application-specific integrated circuit (ASIC), is electrically connected to the output of the acquisition unit 100. It receives the second voltage signal and, based on the circuit architecture of the acquisition unit 100 (e.g., voltage division ratio or amplification factor), calculates the state (including positive and negative values ​​and magnitude) of the first voltage signal. Furthermore, the processing unit MCU is also electrically connected to the charging switch K1 and the discharging switch K2 in the power supply circuit L, controlling the on / off state of the charging switch K1 or the discharging switch K2 through output control signals.

[0024] The working principle of the battery management circuit in this embodiment is as follows: When a power device (charger or load) is connected to the power circuit L, the acquisition unit 100 detects the voltage signal (first voltage signal) at the negative terminal C- of the load in real time through port J1. For example, if the power device is a charger, the first voltage signal is negative; if the power device is a load, the first voltage signal is positive. The acquisition unit 100 converts the first voltage signal into a second voltage signal suitable for recognition by the processing unit MCU through an internal voltage divider resistor network or amplifier circuit, and outputs it to the processing unit MCU through port J2.

[0025] After receiving the second voltage signal, the processing unit MCU calculates the specific value and positive / negative state of the first voltage signal in reverse, based on the circuit parameters of the acquisition unit 100 (such as voltage division ratio or amplification factor). The processing unit MCU has a preset voltage threshold range, for example: If the first voltage signal is negative and within the range C1, then the power device is determined to be a qualified charger.

[0026] If the first voltage signal is positive or within the range C2, then the power device is determined to be the load.

[0027] Based on the state of the first voltage signal, the processing unit MCU outputs a corresponding control signal to control the on / off state of charging switch K1 or discharging switch K2: If the power device is determined to be a charger and the voltage is within a safe range, the processing unit MCU outputs a control signal to turn on the charging switch K1 and turn off the discharging switch K2 (the charging current flows through the body diode of the discharging switch K2), allowing the charger to charge the target battery.

[0028] If the power device is determined to be the load, the processing unit MCU outputs a control signal to turn on the discharge switch K2 and turn off the charging switch K1 (the discharge current flows through the body diode of the charging switch K1), allowing the target battery to supply power to the load.

[0029] If the power device is determined to be a charger but the voltage exceeds the safe range (e.g., too high or too low), the processing unit MCU keeps both the charging switch K1 and the discharging switch K2 open. At the same time, it can issue a warning signal through an external interface (such as an LED or communication module) to prompt the user to replace it with a suitable charger.

[0030] Therefore, the battery management circuit in this embodiment can accurately distinguish between a charger and a load, avoiding misoperation. It determines whether the charger voltage is within a safe range to prevent overcharging or undercharging from damaging the battery. Based on the power device status, it intelligently controls the on / off switching of charging switch K1 and discharging switch K2, improving battery management efficiency. Furthermore, the circuit design is simple, has low power consumption, and is suitable for sleep / wake-up scenarios in BMS systems.

[0031] On the other hand, such as Figure 2 The acquisition unit 100 includes a first switching transistor Q1 and a first voltage source VC1. One controllable connection terminal of the first switching transistor Q1 is electrically connected to the negative terminal C- of the power device through a first resistor R1, and the other controllable connection terminal of the first switching transistor Q1 is grounded through a second resistor R2. The first voltage source VC1 is electrically connected to the processing unit MCU through a third resistor R3, and the first voltage source VC1 is also grounded through a series connection of the third resistor R3 and the second resistor R2.

[0032] When a power device (charger or load) is connected to the power circuit L, the first switch Q1 is turned on, causing the voltage signal (first voltage signal) at the negative terminal C- of the power device to be transmitted to the input terminal of the first switch Q1 through the first resistor R1. The first voltage signal may be positive or negative, depending on the type of power device.

[0033] Since the processing unit MCU cannot directly process negative voltage signals, this embodiment introduces a fixed positive voltage (e.g., +3.3V) through the first voltage source VC1, which is then superimposed on the first voltage signal at the side of the third resistor R3 closest to the processing unit MCU to generate a second voltage signal. Specifically: The first voltage source VC1 outputs a positive voltage through the third resistor R3, which is superimposed on the first voltage signal transmitted through the first switch Q1 and the second resistor R2 on the side of the third resistor R3 closer to the processing unit MCU.

[0034] The second resistor R2 and the third resistor R3 form a voltage divider network. By adjusting the range of the superimposed voltage, the second voltage signal is always positive (e.g., 0.5V to 3.3V), which is suitable for acquisition by the ADC module of the processing unit MCU.

[0035] Specifically, assume that the first resistor R1 is 62K, the second resistor R2 and the third resistor R3 are both 2K, the first voltage source VC1 is 3.3V, the first voltage signal is V1, and the second voltage signal is V2.

[0036] According to Kirchhoff's current law: the current flowing into node A is equal to the current flowing out of node A.

[0037] Therefore, when the first switch Q1 is turned on, we have: (3.3-V2) / 2+(V1-V2) / 62=V2 / 2; V1 = 63V2 - 31x3.3; Therefore, by substituting the specific V2 value collected by the MCU processing unit into the above formula, the specific voltage value of V1 can be obtained.

[0038] In this embodiment, the acquisition range of the MCU acquisition pin V2 is 0~3.3V, so the voltage range of V1 is -102.3V~105.6V. The voltage acquisition range of V1 can be adjusted by the resistance ratio of the first resistor R1, the second resistor R2, and the third resistor R3.

[0039] On the other hand, the first switching transistor Q1 includes a first MOSFET Q10 and a second MOSFET Q11 connected in series, with the body diodes in the first MOSFET Q10 and the second MOSFET Q11 having opposite bias directions. Thus, when the acquisition unit 100 is not required to operate, neither positive nor negative voltages from the power device can pass through, thereby enabling or disabling the load detection function according to user needs.

[0040] On the other hand, the gates of the first MOSFET Q10 and the second MOSFET Q11 are electrically connected to the node between the first MOSFET Q10 and the second MOSFET Q11 through a common pull-down resistor R0. By setting this pull-down resistor R0, it is ensured that the first MOSFET Q10 and the second MOSFET Q11 can be stably kept in the off state when there is no input signal.

[0041] On the other hand, the control terminal of the first switch Q1 is electrically connected to the processing unit MCU through port J3 (i.e., the gates of the first MOSFET Q10 and the second MOSFET Q11). Therefore, the processing unit MCU can control the on / off state of the first switch Q1, thereby enabling or disabling the load detection function of the management circuit.

[0042] Specifically, the control terminal of the first switching transistor Q1 is electrically connected to the enable terminal EN of the processing unit MCU.

[0043] On the other hand, the voltage detection circuit also includes a switching unit, which includes a second switching transistor Q2, a third switching transistor Q3, and a second voltage source VC2. The control terminal of the second switching transistor Q2 is electrically connected to the processing unit MCU through a voltage divider resistor circuit. One controllable connection terminal of the second switching transistor Q2 is grounded, and the other controllable connection terminal of the second switching transistor Q2 is electrically connected to the control terminal of the third switching transistor Q3 through a fourth resistor R4. One controllable connection terminal of the third switching transistor Q3 is electrically connected to the second voltage source VC2, and the other controllable connection terminal of the third switching transistor Q3 is electrically connected to the control terminal of the first switching transistor Q1 through a fifth resistor R5.

[0044] Upon power-on, the processing unit MCU sends an enable signal, which is applied to the control terminal of the second switch Q2 through a voltage divider resistor circuit, causing the second switch Q2 to conduct, which in turn causes the third switch Q3 to conduct. Then, the second voltage source VC2 is applied to the control terminal of the first switch Q1, causing the two MOSFETs of the first switch Q1 to conduct.

[0045] In this embodiment, both the second switch Q2 and the third switch Q3 are transistors. The second switch Q2 is an NPN transistor, and the third switch Q3 is a PNP transistor.

[0046] On the other hand, the voltage divider resistor circuit includes a sixth resistor R6 and a seventh resistor R7. The sixth resistor R6 is located between the control terminal of the second switch Q2 and the processing unit MCU, and the seventh resistor R7 is located between the control terminal of the second switch Q2 and the ground terminal.

[0047] It should also be noted that an eighth resistor R8 is provided between the control terminal and the emitter terminal (that is, the terminal connected to the second voltage source VC2) of the third switch Q3.

[0048] On the other hand, it also includes a battery status acquisition unit (AFE). One end of the battery status acquisition unit (AFE) is electrically connected to each battery cell in the target battery to acquire the voltage and / or temperature of each battery cell. The other end of the battery status acquisition unit (AFE) is electrically connected to the processing unit (MCU). The processing unit (MCU) also controls the state of the charging switch K1 or the discharging switch K2 according to the parameters acquired by the battery status acquisition unit (AFE).

[0049] Specifically, each voltage acquisition channel of the battery status acquisition unit (AFE) is connected to the positive and negative terminals of one battery cell. The voltage signal across the battery cell is amplified by a differential amplifier and then converted into a digital signal by an internal ADC. For example, for a 4-cell battery pack, the AFE will acquire the voltage values ​​of each of the 4 battery cells (e.g., 3.7V, 3.65V, 3.72V, and 3.68V).

[0050] The battery status acquisition unit (AFE) collects temperature signals from key locations of the battery cell or battery pack using temperature sensors (such as NTC thermistors). The temperature sensor outputs a voltage signal proportional to the temperature, which is then processed by the internal circuitry and converted into a digital temperature value.

[0051] The battery status acquisition unit (AFE) transmits the acquired voltage and temperature data to the processing unit (MCU) via a communication interface (such as I2C or SPI). After receiving the data, the MCU analyzes and judges the data according to a preset algorithm.

[0052] The processing unit (MCU) combines voltage and temperature parameters to comprehensively determine whether the battery pack's current operating status is normal and decides whether protective measures are needed. It then outputs corresponding control signals to control the on / off state of charging switch K1 or discharging switch K2. If the voltage of a battery cell exceeds the safety limit or the temperature is too high, the processing unit MCU will disconnect the charging switch K1 to prevent further charging and overcharging.

[0053] If the voltage of a battery cell is lower than the safety limit or the temperature is too low, the processing unit MCU will disconnect the discharge switch K2 to prevent further discharge and thus prevent over-discharge or low-temperature damage.

[0054] If the voltage and temperature of all battery cells are within a safe range and the voltage balance is good, the processing unit MCU determines the conduction state of charging switch K1 or discharging switch K2 according to the load requirements, allowing normal charging and discharging.

[0055] In summary, this utility model discloses a rechargeable battery management circuit, which includes a voltage detection circuit. This voltage detection circuit acquires a first voltage signal from the negative terminal C- of the power device through a data acquisition unit 100 and converts it into a second voltage signal that can be recognized by a processing unit MCU. The processing unit MCU calculates the state of the first voltage signal based on the second voltage signal and the circuit architecture of the data acquisition unit 100. Since the voltage signal at the negative terminal C- typically exhibits different states when a charger and a load are connected, analyzing the state of the first voltage signal can accurately distinguish whether a charger or a load is currently connected.

[0056] Furthermore, upon recognizing the charger, the processing unit (MCU) can further determine whether the charger's voltage is within a safe range by calculating the magnitude of the first voltage signal. This ability to promptly determine whether the charger meets charging requirements upon connection avoids inappropriate charging behavior, significantly improving battery safety and lifespan.

[0057] Furthermore, the above solution, through the precise identification function of the voltage detection circuit, can quickly determine whether a charger is connected and wake up the management circuit from its sleep state. This efficient detection and wake-up mechanism avoids unnecessary power consumption, extends battery standby time, and has the indirect effect of energy saving and environmental protection.

[0058] The above-disclosed embodiments are merely preferred embodiments of the present utility model and should not be construed as limiting the scope of the present utility model. Therefore, any equivalent changes made in accordance with the scope of the present utility model application are still within the scope of the present utility model.

Claims

1. A rechargeable battery management circuit with load detection function, characterized in that, include: A power circuit connecting a rechargeable target battery and a power device, the power device including a charger or load, the power circuit being provided with a charging switch and a discharging switch; A voltage detection circuit, which includes a data acquisition unit and a processing unit; The input terminal of the acquisition unit is electrically connected to the power circuit and to the negative terminal of the power device. The output of the acquisition unit is electrically connected to the processing unit. The acquisition unit is used to generate a second voltage signal that can be recognized by the processing unit based on the first voltage signal of the negative terminal of the power device. The processing unit is also electrically connected to the charging switch and the discharging switch, and is used to calculate the state of the first voltage signal based on the second voltage signal and the circuit architecture of the acquisition unit, and control the on / off state of the charging switch or the discharging switch based on the state of the first voltage signal.

2. The rechargeable battery management circuit according to claim 1, characterized in that, The acquisition unit includes a first switching transistor and a first voltage source; one controllable connection terminal of the first switching transistor is electrically connected to the negative terminal of the power device through a first resistor, and the other controllable connection terminal of the first switching transistor is grounded through a second resistor; the first voltage source is electrically connected to the processing unit through a third resistor, and the first voltage source is also grounded through the series connection of the third resistor and the second resistor.

3. The rechargeable battery management circuit according to claim 2, characterized in that, The first switching transistor includes a first MOSFET and a second MOSFET connected in series, and the body diodes in the first MOSFET and the second MOSFET are biased in opposite directions.

4. The rechargeable battery management circuit according to claim 3, characterized in that, The gates of the first MOSFET and the second MOSFET are electrically connected to the node between the first MOSFET and the second MOSFET through a common pull-down resistor.

5. The rechargeable battery management circuit according to claim 2, characterized in that, The control terminal of the first switching transistor is electrically connected to the processing unit.

6. The rechargeable battery management circuit according to claim 5, characterized in that, The control terminal of the first switching transistor is electrically connected to the enable terminal of the processing unit.

7. The rechargeable battery management circuit according to claim 5, characterized in that, The voltage detection circuit further includes a switching unit, which includes a second switching transistor, a third switching transistor, and a second voltage source. The control terminal of the second switching transistor is electrically connected to the processing unit through a voltage divider resistor circuit. One controllable connection terminal of the second switching transistor is grounded, and the other controllable connection terminal of the second switching transistor is electrically connected to the control terminal of the third switching transistor through a fourth resistor. One controllable connection terminal of the third switching transistor is electrically connected to the second voltage source, and the other controllable connection terminal of the third switching transistor is electrically connected to the control terminal of the first switching transistor through a fifth resistor.

8. The rechargeable battery management circuit according to claim 7, characterized in that, Both the second and third switching transistors are bipolar transistors.

9. The rechargeable battery management circuit according to claim 7, characterized in that, The voltage divider resistor circuit includes a sixth resistor and a seventh resistor. The sixth resistor is disposed between the control terminal of the second switching transistor and the processing unit, and the seventh resistor is disposed between the control terminal of the second switching transistor and the ground terminal.

10. The rechargeable battery management circuit according to claim 1, characterized in that, It also includes a battery status acquisition device, one end of which is electrically connected to each battery cell in the target battery to acquire the voltage and / or temperature of each battery cell, and the other end of which is electrically connected to the processing unit. The processing unit also controls the state of the charging switch or the discharging switch according to the parameters acquired by the battery status acquisition device.

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