A charging and discharging control circuit with charging self-protection function

Abstract

The present application provides a charge and discharge control circuit with a charging self-protection function, which has a common charge and discharge positive electrode, and a separated charge negative electrode and discharge negative electrode, including a first detection circuit, a trigger circuit, a battery protection chip, a charge control circuit and a discharge control circuit. When the first detection circuit detects that a charging device is connected, the battery protection chip enters a working mode and outputs a control signal through a trigger circuit. The charge control circuit includes a first switch tube, a first relay and a charge self-protection circuit. The connection and disconnection of the battery negative electrode and the charge negative electrode are controlled by a charge control signal and the connection of the charging device. The discharge control circuit controls the connection and disconnection of the battery negative electrode and the discharge negative electrode through a discharge control signal. The charge and discharge control circuit provided in the present application can enter a charging mode from a dormant state after the charging device is connected without communicating with the main control chip, and can ensure that the charging end is not charged after the charging device is removed, thereby ensuring the safety of charging and discharging.

Description

Technical Field

[0001] The present application belongs to the technical field of battery charge and discharge control, and specifically provides a charge and discharge control circuit with a charging self-protection function. Background Art

[0002] The charging and discharging ports of rechargeable batteries can adopt different modes such as the same port, full-split port and half-split port. Among them, the half-split port mode generally adopts the same port setting for the positive pole of charging and discharging, and the separate port setting for the negative pole. This can not only solve the problem that the same port mode cannot charge and discharge at the same time, but also is simpler in circuit design and complexity than the full-split port mode, and has higher stability. It is a commonly used battery charging and discharging architecture.

[0003] Existing battery management solutions that use a half-split charging and discharging mode generally require a dedicated battery protection chip to continuously receive and execute instructions from control units such as a host computer and a main control chip to achieve separate control of the charging circuit and the discharging circuit. However, when using a half-split charging and discharging control circuit on an embedded device with relatively tight computing resources, in order to avoid occupying computing resources, the battery protection chip needs to be able to autonomously control the charging and discharging process and ensure that the charging port is not charged when the charger is removed, that is, to achieve the "charge only, no discharge" function of the charging port to avoid discharge in the event of accidental touch. Summary of the invention

[0004] The purpose of the present application is to solve the problems existing in the above-mentioned prior art and to provide a charge and discharge control circuit with a charging self-protection function.

[0005] The embodiments of the present application can be implemented through the following technical solutions:

[0006] A charge and discharge control circuit with a charge self-protection function, having a common charge and discharge positive electrode, and a separate charge negative electrode and discharge negative electrode, comprising:

[0007] A first detection circuit, used to detect the connection status of the charging device and output a first detection result;

[0008] a trigger circuit, enabled by the first detection result, and configured to output a trigger signal when the first detection result is that a charging device is connected;

[0009] A battery protection chip switches between a working mode and a sleep mode according to whether the trigger signal is received, and outputs a charging control signal and a discharging control signal through a charging control terminal and a discharging control terminal respectively in the working mode;

[0010] A charging control circuit, comprising a first switch tube, a first relay and a charging self-protection circuit, wherein the first switch tube is enabled by the charging control signal and is used to control the connection and disconnection between the charging negative electrode and one end of the coil of the first relay, the other end of the coil of the first relay is connected to the charging and discharging positive electrode, the first relay controls the connection and disconnection between the charging negative electrode and the negative electrode of the battery according to whether there is a potential difference between the two ends of the coil, and the self-protection circuit is enabled by the access status of the charging device and is used to control the connection and disconnection between the charging control end and the enabling end of the first switch tube;

[0011] The discharge control circuit is enabled by the discharge control signal and is used to control the connection and disconnection between the discharge negative electrode and the battery negative electrode.

[0012] Furthermore, the charging self-protection circuit includes a charging self-protection optocoupler and a current limiting resistor, the positive electrode of the charging self-protection optocoupler is connected to the positive electrode of the charging device through the current limiting resistor, the negative electrode is connected to the negative electrode of the charging device, the first end is connected to the charging control end, and the second end is connected to the enable end of the first switch tube.

[0013] Preferably, a potential detection circuit is also connected between the second end of the charging self-protection optocoupler and the enable end of the first switch tube, which is used to control the connection and disconnection of the second end of the charging self-protection optocoupler and the enable end of the first switch tube according to whether the potential of the second end of the charging self-protection optocoupler is higher than a preset potential threshold.

[0014] Furthermore, the discharge control circuit includes a second switch tube and a second relay, the enable end of the second switch tube is connected to the discharge control end, and is used to control the connection and disconnection of the negative electrode of the battery and one end of the coil of the second relay, the other end of the coil of the second relay is connected to the charging and discharging positive electrode, and the second relay controls the connection and disconnection of the negative electrode of the battery and the negative electrode of the discharge according to whether there is a potential difference between the two ends of its coil.

[0015] Preferably, the charging and discharging positive electrode and the power supply end of the battery protection chip are both connected to the positive electrode of the battery; the first mode end of the battery protection chip is connected to the output end of the trigger circuit, and the potential of the trigger signal is equal to the potential of the positive electrode of the battery.

[0016] Furthermore, the trigger circuit includes a third switch tube, an enable end of the third switch tube is connected to the output end of the first detection circuit, and when the first detection result is that the charging device is connected, the positive electrode of the battery is connected to the output end of the trigger circuit.

[0017] Furthermore, the first detection circuit includes a first detection optocoupler and a first resistor, the positive electrode of the first detection optocoupler is connected to the charging and discharging positive electrode through the first resistor, the negative electrode is connected to the charging negative electrode, the first end is connected to the negative electrode of the battery, and the second end is connected to the enable end of the trigger circuit as an output end.

[0018] Preferably, the charge and discharge control circuit with self-protection function also includes a second detection circuit, which is used to detect whether the discharge negative electrode is connected to a power circuit and output a corresponding second detection result; the trigger circuit is also enabled by the second detection result, and is used to output a trigger signal when the second detection result is dischargeable.

[0019] Preferably, the charge and discharge control circuit with self-protection function further includes a manual trigger circuit for manually outputting a trigger signal.

[0020] Preferably, any port of the battery protection chip is not communicatively connected to the main control chip.

[0021] The embodiment of the present application provides a charging and discharging control circuit with a charging self-protection function. By monitoring the access status of the charging device, the battery protection chip is automatically activated after the charging device is connected, and after the charging device is removed, the charging port is no longer powered. Therefore, the charging and discharging of the battery is autonomously controlled without the control of the main control chip, and the charging-only function of the charging port is realized, thereby ensuring safety of use. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A partial circuit diagram of a charge and discharge control circuit with a charge and discharge self-protection function provided according to an embodiment of the present application;

[0023] Figure 2 A partial circuit diagram of a charge and discharge control circuit with a charge and discharge self-protection function provided according to an embodiment of the present application;

[0024] Figure 3 for Figure 1 Pinout of the battery protection chip;

[0025] Figure 4 It is a partial circuit diagram of a charge and discharge control circuit with charge and discharge self-protection function provided according to an embodiment of the present application.

[0026] Numbers in the figure

[0027] 100: first detection circuit, 200: trigger circuit, 300: charging control circuit, 400: discharging control circuit, 500: second detection circuit. DETAILED DESCRIPTION

[0028] Hereinafter, the present application will be further described based on preferred embodiments with reference to the accompanying drawings.

[0029] For ease of understanding, various components on the drawings are enlarged or reduced, but this practice is not intended to limit the scope of protection of this application. In addition, in the description of this application, in order to distinguish different units, the words "first", "second" and so on are used in this specification, but these are not limited by the order of manufacture, nor can they be understood as indicating or implying relative importance. Their names may be different in the detailed description and claims of this application.

[0030] The vocabulary in this specification is used to illustrate the embodiments of the present application, but is not intended to limit the present application. It should also be noted that, unless otherwise clearly specified and limited, the terms "disposed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, a direct connection, an indirect connection through an intermediate medium, or a connection between the two elements. For those skilled in the art, the specific meanings of the above terms in this application can be specifically understood.

[0031] The present application provides a charge and discharge control circuit with a charging self-protection function. Figures 1 to 4 The circuit schematics of various parts of the charge and discharge control circuit with charging self-protection function in some preferred embodiments are respectively shown. As shown in the figure, it includes a battery protection chip U1, a first detection circuit 100, a trigger circuit 200, a charging control circuit 300, and a discharging control circuit 400.

[0032] The control circuit uses a half-split mode to control the charging and discharging process of the battery. Specifically, it has a common charging and discharging positive electrode B+, and a separated charging negative electrode C- and discharging negative electrode P-. In the embodiment of the present application, the charging and discharging positive electrode B+ is directly connected to the positive electrode of the battery, and the negative electrode of the battery is marked as a ground terminal in the figure, and its connection and disconnection with the charging negative electrode C- and the discharging negative electrode P- are controlled by the control circuit provided by the present application.

[0033] The circuit structure and working principle of each part of the control circuit are described in detail below in conjunction with the accompanying drawings.

[0034] Figure 3 FIG. 4 shows the pin distribution of the battery protection chip U1 in some preferred embodiments. Figure 3 The battery protection chip model selected is SH367309, whose pin 48 is the power supply terminal VBAT, which is used to connect to the external power supply, and its pin 43 is the first mode terminal SHIP. When the SHIP terminal is at a low level, the battery protection chip U1 is in sleep mode (or storage mode). At this time, its charging control terminal CHG ( Figure 3 Pin 36) and discharge control terminal DSG ( Figure 3The pins 34 in the middle are both in a floating state. When the SHIP terminal is pulled up to the same potential as the VBAT terminal, the battery protection chip U1 is activated to the working mode. At this time, it outputs a charging control signal and a discharging control signal with high and low levels to the charging control circuit 300 and the discharging control circuit 400 through the CHG terminal and the DSG terminal, respectively. In addition, in some preferred embodiments, as Figure 3 As shown, the battery protection chip U1 also has a second mode terminal MODE ( Figure 3 When the battery protection chip U1 is in working mode, it can further switch to different subdivided charging and discharging modes such as overcharge protection, over-discharge protection, and high temperature protection according to the voltage and current detection values ​​of the charging port and the discharging port and the temperature of the battery.

[0035] In some existing battery charge and discharge control circuits, SH367309 or similar BMS management chips generally need to be in working mode continuously and communicate with host computers, MCUs and other main control units, and control the battery charge and discharge process by sending battery status information to the main control unit and receiving control instructions returned by the main control unit. However, for application areas such as new energy vehicles, the main control unit VCU requires a large amount of computing resources to analyze and process sensor signals, run route planning, emergency situation identification and risk avoidance algorithms, etc., to ensure the safety of the vehicle's driving process. If the monitoring and management of the battery unnecessarily occupy the communication and computing resources of the main control unit, it will inevitably affect the main control unit's safe control of the vehicle's driving.

[0036] To this end, in the embodiment of the present application, any port of the battery protection chip U1 is not communicated with the main control chip, and the battery protection chip is activated only by its own circuit design, and is autonomously controlled according to the conditions of the charging and discharging ports.

[0037] In the embodiments of the present application, Figure 1 As shown, activation of the battery protection chip U1 is achieved through the first detection circuit 100 and the trigger circuit 200 .

[0038] The first detection circuit 100 is used to detect the connection status of the charging device and output a first detection result, such as Figure 1As shown, in some preferred embodiments, the first detection circuit 100 includes a first detection optocoupler J1 and a first resistor R16, wherein the positive electrode of the first detection optocoupler J1 is connected to the charging and discharging positive electrode B+ through the first resistor R16, the negative electrode is connected to the charging negative electrode C-, the first end is connected to the negative electrode of the battery (i.e., the ground end), and the second end is connected to the enable end of the trigger circuit 200 as an output end. When no charging device is connected, the light-emitting diode of the first detection optocoupler J1 does not emit light, and its second end outputs a floating first detection result to the enable end of the trigger circuit 200 and cannot trigger the trigger circuit 200; when a charging device such as a charger is connected, the first resistor R16 and the light-emitting diode of the first detection optocoupler form an electric circuit, the light-emitting diode emits light and turns on the first end and the second end of the first detection optocoupler J1, thereby outputting a grounded low-level signal as the first detection result to the enable end of the trigger circuit 200, causing the trigger circuit 200 to be triggered.

[0039] The trigger circuit 200 is enabled by the first detection result, and is used to output a trigger signal when the first detection result is that the charging device is connected. Figure 1 As shown, the trigger circuit includes a third switch tube Q1, which is turned on at a low level, and its enable terminal (G pole) is connected to the output terminal of the first detection optocoupler J1, the S pole is connected to the VBAT terminal of the battery protection chip, and the D pole is connected to the SHIP terminal of the charging protection chip as the output terminal. When the third switch tube Q1 is not turned on, the potential of the SHIP terminal is pulled down to the ground terminal by the pull-down resistor R17. When the first detection result is that the charging device is connected, the third switch tube Q1 is turned on, and the SHIP terminal is connected to the VBAT terminal, thereby triggering the battery protection chip to change from a sleep state to a working state.

[0040] As described above, after the battery protection chip U1 enters the working mode, it outputs a charging control signal and a discharging control signal to the charging control circuit 300 and the discharging control circuit 400 through the CHG terminal and the DSG terminal respectively.

[0041] In the embodiment of the present application, since the charging and discharging positive electrode B+ is in a connected state with the positive electrode of the battery, the charging process is controlled, that is, the connection and disconnection of the battery negative electrode (i.e., the ground terminal) and the charging negative electrode C- are switched to ensure that the battery negative electrode and the charging negative electrode C- are connected when the charging device is connected. After the charging device is removed, regardless of whether it is in a discharging state or not, the connection between the battery negative electrode and the charging negative electrode C- is disconnected to make the discharge port uncharged, so as to avoid the occurrence of accidental connection of electrical equipment and accidental electric shock.

[0042] like Figure 3As shown, in the embodiment of the present application, the charging control circuit 300 includes a first switch tube Q9, a first relay JK1 and a charging self-protection circuit 310, wherein the enable end (G pole) of the first switch tube Q9 is used to input the charging control signal of the CHG end, its S pole is connected to one end of the switch of the first relay JK1, and its D pole is connected to one end of the coil of the first relay JK1. The other end of the switch of the first relay is connected to the negative electrode of the battery, and the other end of the coil of the first relay JK1 is connected to the charging and discharging positive electrode B+. Among them, the first switch tube Q9 is used to control the connection and disconnection of the charging negative electrode and one end of the coil of the first relay JK, and the first relay JK1 controls the connection and disconnection of the charging negative electrode C- and the negative electrode of the battery according to whether there is a potential difference between the two ends of its coil.

[0043] Specifically, the battery protection chip U1 enters the working mode after being triggered, and outputs a high-level charging control signal through the CHG terminal. At this time, the first switch tube Q9 is turned on, and the two ends of the coil of the first relay JK1 are respectively at the same potential as the charging and discharging positive electrode B+ and the charging negative electrode C-. At this time, if no charging device is connected, the charging negative electrode C- is in a floating state, and the switch of the first relay JK1 is not attracted, so the battery negative electrode and the charging negative electrode C- are not connected, and the charging negative electrode C- is not charged. When a charging device is connected, a potential difference is formed at the two ends of the coil of the first relay JK1, thereby attracting its switch and connecting the battery negative electrode and the charging negative electrode C-, and entering normal charging.

[0044] The self-protection circuit 310 is enabled by the access status of the charging device, and is used to control the on-off of the charging control terminal CHG and the enable terminal of the first switch tube Q9. Specifically, the charging self-protection circuit 310 includes a charging self-protection optocoupler and a current limiting resistor R23, wherein the positive electrode of the charging self-protection optocoupler J2 is connected to the positive electrode of the charging device through the current limiting resistor R23, the negative electrode is connected to the negative electrode of the charging device, the first end is connected to the charging control terminal CHG, and the second end is connected to the enable terminal of the first switch tube Q9.

[0045] The purpose of setting the self-protection circuit 310 is that if the enable end of the first switch tube Q9 always receives a high-level charging control signal, when the switch of the first relay JK1 is attracted by its coil, even when the charging is completed and the charging device is removed, the two ends of the coil of JK1 still maintain the connection between the battery positive electrode B+ and the battery negative electrode (ground terminal), causing its switch to be continuously attracted and unable to be disconnected, so that after the charging device is connected once, the charging port cannot be automatically powered off by removal. To this end, through the self-protection circuit 310, the charging control signal can only be output to the first switch tube Q9 when the charging device is connected. When no charging device is connected, the connection between the charging negative electrode C- and the coil of JK1 is disconnected, so that it cannot attract the switch, thereby automatically disconnecting the connection between the battery negative electrode and the charging negative electrode.

[0046] In some preferred embodiments, Figure 3 As shown, a potential detection circuit 320 is also connected between the second end of the charging self-protection optocoupler and the enable end of the first switch tube Q9. The potential detection circuit 320 controls the connection and disconnection of the second end of the charging self-protection optocoupler and the enable end of the first switch tube Q9 according to whether the potential of the second end of the charging self-protection optocoupler is higher than a preset potential threshold, so as to avoid the noise current of the CHG port causing the first switch tube Q9 to be mistakenly turned on.

[0047] In the embodiment of the present application, the discharge control circuit 400 is enabled by the discharge control signal output by the discharge control terminal DSG, and is used to control the connection and disconnection between the discharge negative electrode P- and the negative electrode of the battery. Figure 3 As shown, the discharge control circuit 400 includes a second switch tube Q11 and a second relay JK2. The enable terminal (G pole) of the second switch tube Q11 is connected to the discharge control terminal DSG, the S pole is connected to the negative pole of the battery, the D pole is connected to one end of the coil of the second relay JK2, the other end of the coil of the second relay JK2 is connected to the positive pole of the charge and discharge B+, and the two ends of the switch of the second relay JK2 are respectively connected to the negative pole of the battery and the negative pole of the discharge P-. When the discharge control terminal DSG outputs a high-level discharge control signal, the second switch tube Q11 is turned on. At this time, the two ends of the coil of the second switch tube Q11 are respectively connected to the positive pole of the charge and discharge B+ and the negative pole of the battery to form a potential difference, thereby attracting its switch to turn on the switch, so that the negative pole of the battery is connected to the negative pole of the discharge P-, and normal discharge is achieved; when the discharge control terminal DSG outputs a low-level discharge control signal, or is floating, Q11 is disconnected, and the negative pole of the discharge P- is disconnected from the negative pole of the battery, and the battery is prohibited from discharging through the negative pole of the discharge P-.

[0048] In some preferred embodiments, the charge and discharge control circuit with self-protection function also includes a second detection circuit 500, which is used to detect whether the discharge negative electrode P- is connected to a power circuit and output a corresponding second detection result; the trigger circuit 200 is also enabled by the second detection result, and is used to output a trigger signal when the second detection result is dischargeable.

[0049] Figure 2 4 shows a specific circuit schematic diagram of the second detection circuit 500, such as Figure 2As shown, the second detection circuit can be composed of a second detection optical coupler J3 and a second resistor R19. In some specific embodiments, the light-emitting diode of the second detection optical coupler J3 and the power circuit formed by the second resistor R19 can be turned on or off by a mechanical or electrically controlled switch to control the battery protection chip U1 to be continuously in a working state when the battery needs to be discharged. For example, the first end of the second detection optical coupler J3 can be connected to a 5V power supply, and a switch tube is arranged between it and the second resistor R19, and a high-level signal is sent through the main control unit to keep it turned on, so that the second detection circuit continues to send a discharge trigger signal to ensure that the battery is continuously discharged through the discharge negative electrode P-.

[0050] In some preferred embodiments, the charge and discharge control circuit with self-protection function further includes a manual trigger circuit for manually outputting a trigger signal, for example Figure 4 As shown in , the two ends of the pop-up button can be connected to the VBAT end and the SHP end respectively, so that the battery protection chip U1 is started when the button is pressed.

[0051] Table 1 below lists the status of the battery protection chip and the charging and discharging interface charging conditions of the charge and discharge control circuit with charging self-protection function provided by the above preferred embodiment in various power usage scenarios:

[0052] Table 1

[0053]

[0054] It can be seen from Table 1 that the charge and discharge control circuit with charging self-protection function provided in the above preferred embodiment can ensure that the battery protection chip U1 is automatically activated after the charging device is connected, and after the charging device is removed, the charging port is no longer charged, thereby autonomously realizing the control of battery charging and discharging on the basis of no control by the main control chip, and realizing the charging-only function of the charging port, which effectively reduces the communication and computing pressure of the main control chip while ensuring the safety of use.

[0055] The above is a detailed introduction to the specific implementation methods of the present application. For those skilled in the art, several improvements and modifications may be made to the present application without departing from the principles of the present application. These improvements and modifications also fall within the scope of protection of the claims of the present application.

Claims

1. A charge and discharge control circuit with a charge self-protection function, having a common charge and discharge positive electrode, and a separate charge negative electrode and discharge negative electrode, It is characterized in that include: A first detection circuit, used to detect the connection status of the charging device and output a first detection result; a trigger circuit, enabled by the first detection result, and configured to output a trigger signal when the first detection result is that a charging device is connected; A battery protection chip switches between a working mode and a sleep mode according to whether the trigger signal is received, and outputs a charging control signal and a discharging control signal through a charging control terminal and a discharging control terminal respectively in the working mode; A charging control circuit, comprising a first switch tube, a first relay and a charging self-protection circuit, wherein the first switch tube is enabled by the charging control signal and is used to control the connection and disconnection between the charging negative electrode and one end of the coil of the first relay, the other end of the coil of the first relay is connected to the charging and discharging positive electrode, the first relay controls the connection and disconnection between the charging negative electrode and the negative electrode of the battery according to whether there is a potential difference between the two ends of the coil, and the self-protection circuit is enabled by the access status of the charging device and is used to control the connection and disconnection between the charging control end and the enabling end of the first switch tube; A discharge control circuit, enabled by the discharge control signal, for controlling the connection and disconnection between the discharge cathode and the battery cathode; The charging self-protection circuit includes a charging self-protection optocoupler and a current limiting resistor, wherein the positive electrode of the charging self-protection optocoupler is connected to the positive electrode of the charging device through the current limiting resistor, the negative electrode is connected to the negative electrode of the charging device, the first end is connected to the charging control end, and the second end is connected to the enable end of the first switch tube; A potential detection circuit is also connected between the second end of the charging self-protection optocoupler and the enable end of the first switch tube, which is used to control the on and off of the second end of the charging self-protection optocoupler and the enable end of the first switch tube according to whether the potential of the second end of the charging self-protection optocoupler is higher than a preset potential threshold.

2. The charge and discharge control circuit with charging self-protection function according to claim 1, Features: The discharge control circuit includes a second switch tube and a second relay. The enable end of the second switch tube is connected to the discharge control end, and is used to control the connection and disconnection between the negative electrode of the battery and one end of the coil of the second relay. The other end of the coil of the second relay is connected to the positive electrode of charging and discharging. The second relay controls the connection and disconnection between the negative electrode of the battery and the negative electrode of discharging according to whether there is a potential difference between the two ends of its coil.

3. The charge and discharge control circuit with charging self-protection function according to claim 1, Features: The charging and discharging positive electrode and the power supply end of the battery protection chip are both connected to the positive electrode of the battery; The first mode terminal of the battery protection chip is connected to the output terminal of the trigger circuit, and the potential of the trigger signal is equal to the potential of the positive electrode of the battery.

4. The charge and discharge control circuit with charging self-protection function according to claim 3, Features: The trigger circuit includes a third switch tube, an enable end of the third switch tube is connected to the output end of the first detection circuit, and when the first detection result is that the charging device is connected, the positive electrode of the battery is connected to the output end of the trigger circuit.

5. The charge and discharge control circuit with charging self-protection function according to claim 4, Features: The first detection circuit includes a first detection optocoupler and a first resistor, the positive electrode of the first detection optocoupler is connected to the charging and discharging positive electrode through the first resistor, the negative electrode is connected to the charging negative electrode, the first end is connected to the negative electrode of the battery, and the second end is connected to the enable end of the trigger circuit as an output end.

6. The charge and discharge control circuit with charging self-protection function according to claim 1, Features: It also includes a second detection circuit, which is used to detect whether the discharge cathode is connected to an electrical circuit and output a corresponding second detection result; The trigger circuit is also enabled by the second detection result, and is used to output a trigger signal when the second detection result is dischargeable.

7. The charge and discharge control circuit with charging self-protection function according to claim 1, Features: The invention also comprises a manual trigger circuit for manually outputting a trigger signal.

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