A charge and discharge control circuit

Abstract

The present application provides a charge and discharge control circuit for controlling the charging and discharging of a battery, including a first boost circuit, a second boost circuit and a charge and discharge switching circuit; the low potential ends of the first boost circuit and the second boost circuit are both connected to the positive electrode of the battery; the first control end of the charge and discharge switching circuit is connected to the high potential end of the first boost circuit, and the second control end is connected to the high potential end of the second boost circuit; the charge and discharge switching circuit conducts a current path from the positive electrode of the battery to the charge and discharge positive electrode when the voltage at the high potential end of the first boost circuit is higher than a preset threshold voltage, and conducts a current path from the charge and discharge positive electrode to the battery positive electrode when the voltage at the high potential end of the second boost circuit is higher than the threshold voltage. The charge and discharge control circuit provided by the present application avoids the problem of floating charge and discharge negative electrode in the charge and discharge negative electrode control method by performing charge and discharge control between the positive electrode of the battery and the charge and discharge positive electrode.

Description

Technical Field

[0001] The present application belongs to the technical field of rechargeable battery control circuits, and relates to a charge and discharge control technology based on a positive terminal of a battery. Specifically, a charge and discharge control circuit is provided. Background Art

[0002] Controlling the charging and discharging process of rechargeable batteries is a necessary guarantee for their safe use. At present, for batteries using the same port charging and discharging mode (i.e. the charging positive electrode is connected to the discharging positive electrode, and the charging negative electrode is connected to the discharging negative electrode), a low-end control method is generally adopted, that is, a circuit is designed between the negative electrode of the battery and the charging and discharging negative electrode. Figure 1 The charging and discharging control circuit shown.

[0003] The problem with placing the charge and discharge control circuit between the negative electrode of the battery and the negative electrode of the charge and discharge is that the charge and discharge control signal is generally output through the I / O port of a dedicated battery protection chip, and the battery protection chip communicates with the main control chip through the I / O port. When the battery is in a protection state, the negative electrode of the charge and discharge is in a floating state, that is, the ground of the MCU is floating, and the battery protection chip and the MCU do not share a common ground. At this time, the ground voltage of the I / O port connecting the battery protection chip and the MCU may be as high as the battery voltage and cause overvoltage damage to the MCU.

[0004] Therefore, it is necessary to improve the control method of the existing same-port charge and discharge battery to ensure the safety of the charge and discharge control process. Summary of the invention

[0005] In order to solve the problems existing in the above-mentioned prior art, the present application provides a charge and discharge control circuit for controlling the charging and discharging of a battery, wherein the negative electrode of the battery is connected to the charge and discharge negative electrode of the same port;

[0006] The charge and discharge control circuit includes a first boost circuit, a second boost circuit, and a charge and discharge switching circuit connected in series between the positive electrode of the battery and the charge and discharge positive electrode of the same port;

[0007] The low potential ends of the first boost circuit and the second boost circuit are both connected to the positive electrode of the battery;

[0008] The first control terminal of the charge-discharge switching circuit is connected to the high potential terminal of the first boost circuit, and the second control terminal is connected to the high potential terminal of the second boost circuit;

[0009] The charge and discharge switching circuit switches on a current path from the positive electrode of the battery to the positive electrode of the charge and discharge when the voltage at the high potential end of the first boost circuit is higher than a preset threshold voltage, and switches on a current path from the positive electrode of the charge and discharge to the positive electrode of the battery when the voltage at the high potential end of the second boost circuit is higher than the threshold voltage.

[0010] A charge and discharge control circuit provided in an embodiment of the present application controls the battery charging and discharging process by means of a charge and discharge switching circuit arranged between the positive electrode of the battery and the positive electrode of the charge and discharge, thereby effectively solving the problem of floating negative electrode of the charge and discharge existing in the existing low-end control mode and the damage to the MCU that may be caused.

[0011] Furthermore, the charge and discharge switching circuit includes a first NMOS tube, a second NMOS tube, a third capacitor and a fourth capacitor; the S pole of the first NMOS tube and the positive pole of the third capacitor are both connected to the positive pole of the battery; the D pole of the first NMOS tube is connected to the D pole of the second NMOS tube; the negative pole of the third capacitor is connected to the negative pole of the fourth capacitor; the S pole of the second NMOS tube and the positive pole of the fourth capacitor are both connected to the charge and discharge positive pole; the G pole of the first NMOS tube is the first control end, and the G pole of the second NMOS tube is the second control end.

[0012] Preferably, the difference between the threshold voltage and the voltage of the positive electrode of the battery is greater than 11V.

[0013] Furthermore, the first boost circuit includes a plurality of first bootstrap boost sub-circuits connected in series, and each first bootstrap boost sub-circuit includes a first diode and a first capacitor; the positive electrode of the first diode of each first bootstrap boost sub-circuit is directed toward the low potential end of the first boost circuit, and the negative electrode is directed toward the high potential end of the first boost circuit; the positive electrode of the first capacitor of each first bootstrap boost sub-circuit is connected to the negative electrode of the first diode of the first bootstrap boost sub-circuit of this stage, and the negative electrode is used to receive the first boost control signal; each first bootstrap boost sub-circuit adjusts its boost amplitude under the control of the first boost control signal.

[0014] Preferably, when the first boost control signal is a PWM signal, and the first boost control signals received by any two adjacent first bootstrap boost sub-circuits are inverted, the voltage at the high potential end of the first boost circuit is higher than the threshold voltage; when the first boost control signal is a DC signal, the voltage at the high potential end of the first boost circuit is lower than the voltage of the positive electrode of the battery.

[0015] Furthermore, the second boost circuit includes a plurality of stages of second bootstrap boost sub-circuits connected in series, and each stage of the second bootstrap boost sub-circuit includes a second diode and a second capacitor; the positive electrode of the second diode of each stage of the second bootstrap boost sub-circuit is directed toward the low potential end of the second boost circuit, and the negative electrode is directed toward the high potential end of the second boost circuit; the positive electrode of the second capacitor of each stage of the second bootstrap boost sub-circuit is connected to the negative electrode of the second diode of the second bootstrap boost sub-circuit of that stage, and the negative electrode is used to receive the second boost control signal; and the second bootstrap boost sub-circuit of each stage adjusts its boost amplitude under the control of the second boost control signal.

[0016] Preferably, when the second boost control signal is a PWM signal, and the second boost control signals received by any two adjacent second bootstrap boost sub-circuits are inverted, the voltage at the high potential end of the second boost circuit is higher than the threshold voltage; when the second boost control signal is a DC signal, the voltage at the high potential end of the second boost circuit is lower than the voltage of the positive electrode of the battery.

[0017] In an embodiment of the present application, a boost circuit is formed by a multi-stage bootstrap boost circuit, which realizes stable boosting from the positive electrode of the power supply without providing an additional DC power supply, thereby achieving stable control of the charging current path and the discharging current path.

[0018] Preferably, the charge and discharge control circuit further includes a discharge protection circuit for controlling the on-off of the high potential end of the second boost circuit and the second control end.

[0019] Furthermore, the discharge protection circuit includes a first optocoupler and a first resistor; the negative electrode of the first optocoupler is connected to the first end of the first resistor; the first output end is connected to the high potential end of the second boost circuit, and the second output end is connected to the charge and discharge positive electrode.

[0020] Preferably, the anode of the first optical coupler and the second end of the first resistor are respectively connected to the cathode and anode of any fourth diode. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of an existing battery charge and discharge control circuit;

[0022] Figure 2 A schematic diagram of a battery charge and discharge control circuit provided according to some embodiments of the present application;

[0023] Figure 3 A schematic diagram of a battery charge and discharge control circuit provided according to some other embodiments of the present application;

[0024] Figure 4 A schematic diagram of a circuit board of an embedded device including a battery charge and discharge control circuit;

[0025] Figure 5 A schematic diagram of a battery charge and discharge control circuit provided according to some other embodiments of the present application;

[0026] Figure 6 A circuit diagram of performing discharge protection through two discharge control circuits according to some embodiments of the present application.

[0027] Numbers in the figure

[0028] 100: a first boost circuit, 200: a second boost circuit, 300: a charge-discharge switching circuit, 400: a discharge protection circuit, 500: a discharge protection circuit. DETAILED DESCRIPTION

[0029] Hereinafter, the present application will be further described based on preferred embodiments with reference to the accompanying drawings.

[0030] In the description of the embodiments of the present application, it should be noted that if the terms "upper", "lower", "inside", "outside", etc. indicate an orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the products of the embodiments of the present application are usually placed when in use, it is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, in the description of the present application, in order to distinguish different units, the words first, second, etc. 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, and their names may be different in the detailed description and claims of the present application.

[0031] 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.

[0032] Figure 1 This is an existing charge and discharge control circuit that uses a low-end control method. As analyzed in the background technology, when the battery is in a protection state, the charge and discharge negative electrode is in a floating state, that is, the ground of the MCU is floating, and the battery protection chip and the MCU do not share a common ground. At this time, the ground voltage of the I / O port connected to the battery protection chip and the MCU may be as high as the battery voltage and cause overvoltage damage to the MCU. To solve the above problems, the embodiments of the present application provide a charge and discharge control circuit that uses a high-end control method.

[0033] Figure 2 A schematic diagram of a charge and discharge control circuit provided according to an embodiment of the present application is shown, wherein the charge and discharge control circuit is used to control the charging and discharging of a battery, wherein the negative electrode B- of the battery is connected to the charge and discharge negative electrode C- / P- of the same port.

[0034] Specifically, if Figure 2As shown, the charge and discharge control circuit includes a first boost circuit, a second boost circuit, and a charge and discharge switching circuit connected in series between the battery positive electrode B+ and the charge and discharge positive electrode C+ / P+ of the same port. The low potential ends of the first boost circuit and the second boost circuit are both connected to the battery positive electrode B+; the first control end of the charge and discharge switching circuit is connected to the high potential end of the first boost circuit, and the second control end of the charge and discharge switching circuit is connected to the high potential end of the second boost circuit.

[0035] When the voltage at the high potential end of the first boost circuit is higher than the preset threshold voltage, the charge and discharge switching circuit conducts the current path from the battery positive electrode B+ to the charge and discharge positive electrode C+ / P+ (i.e. Figure 2 When the voltage at the high potential end of the second boost circuit is higher than the threshold voltage, the current path from the charging and discharging positive electrode C+ / P+ to the battery positive electrode B+ is turned on.

[0036] The charge and discharge control circuit provided by the present application changes the low-end control mode of the existing charge and discharge battery with the same port structure into a high-end control mode, so that the battery protection chip and the MCU share the same ground, thereby avoiding overvoltage damage to the MCU; at the same time, a first boost circuit and a second boost circuit are respectively provided for raising the voltage based on the positive electrode B+ of the battery, and the raised voltage is used to control the connection of the charging current path and the discharging current path, thereby avoiding the problem that when using DCDC to boost to a fixed voltage, the control terminal voltage cannot guarantee stable control of the charging and discharging current paths due to the real-time change of the battery voltage.

[0037] Figure 3 Schematic diagrams of charge and discharge control circuits provided by some preferred embodiments are shown, such as Figure 3 As shown, the charge and discharge control circuit is composed of a first boost circuit 100, a second boost circuit 200 and a charge and discharge switching circuit 300. Figure 3 The implementation of each part of the control circuit is described in detail.

[0038] <Charging Switching Circuit>

[0039] like Figure 3 As shown, the charge-discharge switching circuit 300 includes a first NMOS transistor Q1, a second NMOS transistor Q2, a first diode D1 and a second diode D2. Among them, the S pole of the first NMOS transistor Q1 and the anode of the first diode D1 are both connected to the battery anode B+; the D pole of the first NMOS transistor Q1 is connected to the D pole of the second NMOS transistor Q2; the cathode of the first diode D1 is connected to the cathode of the second diode D2; the S pole of the second NMOS transistor Q2 and the anode of the second diode D2 are both connected to the charge-discharge anode C+ / P+; the G pole of the first NMOS transistor Q1 is the first control terminal, and the G pole of the second NMOS transistor Q2 is the second control terminal.

[0040] Preferably, the charge-discharge switching circuit 300 further includes peripheral components for protecting the first NMOS transistor, such as Figure 3 The resistors R24, R27 and diode D6 in the embodiment, as well as the peripheral components used to protect the second NMOS tube, such as Figure 3 The resistors R25, R28, and the diode D5, wherein the diodes D6 and D5 are used as voltage stabilizing diodes to provide stable voltage levels for the G poles of the first NMOS tube Q1 and the second NMOS tube Q2, respectively; the resistors R24 and R25 are used to realize the rapid discharge of the capacitor charge when the first NMOS tube Q1 and the second NMOS tube Q2 are turned off, respectively. In other specific embodiments, those skilled in the art can also adjust the above components according to actual circuit design requirements.

[0041] Preferably, if Figure 3 As shown, the charge-discharge switching circuit 300 further includes voltage-stabilizing capacitors C1, C2, C3, C4 and current-limiting resistors R2, R3. The connection methods and functions of the above-mentioned discrete components are well known to those skilled in the art and will not be described in detail here.

[0042] Figure 3 The self-charging and discharging positive electrode C+ / P+ passes through the second diode D2 and the first NMOS tube Q1 to the battery positive electrode B+, which is a unidirectional charging current path. The self-charging and discharging positive electrode C+ / P+ passes through the first diode D1 and the second NMOS tube Q2 to the charging and discharging positive electrode C+ / P+, which is a unidirectional discharging current path. Since the first NMOS tube Q1 and the second NMOS tube Q2 are both turned on at a high level, the charging current path can be turned on only when the voltage of the first control terminal is stably higher than the battery positive electrode B+ by about 11V. Similarly, the discharging current path can be turned on only when the voltage of the second control terminal is stably higher than the battery positive electrode B+ by about 11V.

[0043] Although DCDC can be used to output a fixed voltage to control the on / off of the NMOS tube, the battery voltage changes all the time, and its upper and lower floating range is more than 10V. Since the enable terminal voltage of the NMOS tube must be stably higher than the positive electrode B+11V of the battery to maintain conduction, and too high or too low voltage may cause damage to the MOS tube, a fixed DC boost value is not applicable; in addition, the additional boost voltage source requires separately provided power supply components and peripheral circuit design, which will undoubtedly lead to an increase in circuit scale and cost. For example, for Figure 4 The control circuit board of an embedded device shown in the figure has a circular PCB board with a diameter less than 70 mm, and no additional voltage source components for boosting voltage can be added thereon.

[0044] In order to achieve stable voltage boosting of the battery positive electrode B+ whose voltage fluctuates up and down, in an embodiment of the present application, a first boost circuit 100 and a second boost circuit 200 composed of a multi-stage bootstrap boost circuit can achieve stable voltage boosting of the positive electrode B+ of the self-power supply without providing an additional DC power supply, thereby achieving stable control of the charging current path and the discharging current path.

[0045] <First Boosting Circuit and Second Boosting Circuit>

[0046] Specifically, Figure 3 As shown, the first boost circuit 100 includes 4 stages of first bootstrap boost sub-circuits connected in series, wherein each stage of the first bootstrap boost sub-circuit includes a third diode and a first capacitor. Specifically, the third diode D15 and the first capacitor C32 in FIG. 3 constitute the first bootstrap boost sub-circuit of the first stage, the third diode D13 and the first capacitor C29 constitute the first bootstrap boost sub-circuit of the second stage, the third diode D11 and the first capacitor C25 constitute the first bootstrap boost sub-circuit of the third stage, and the third diode D9 and the first capacitor C23 constitute the first bootstrap boost sub-circuit of the fourth stage.

[0047] The anode of the third diode of each first bootstrap boost sub-circuit is directed toward the low potential end of the first boost circuit 100, and the cathode is directed toward the high potential end of the first boost circuit 100. Specifically, Figure 3 As shown, the third diodes D15, D13, D11, and D9 are connected in series in sequence, the cathode of D15 is connected to the battery positive electrode B+ as the low potential end of the first boost circuit 100, and the positive electrode is connected to the cathode of D13, and the other third diodes are connected in the same direction, and the anode of D9 is connected to the first control end of the charge-discharge switching circuit 300 as the high potential end of the first boost circuit 100. In some preferred embodiments, as Figure 3 As shown, a diode D7 is connected in series between D9 and the first control terminal of the charge-discharge switching circuit 300 .

[0048] Furthermore, the positive electrode of the first capacitor of each first bootstrap boost subcircuit is connected to the negative electrode of the third diode of the first bootstrap boost subcircuit of the same level, and the negative electrode is used to receive the first boost control signal, and each first bootstrap boost subcircuit adjusts its boost amplitude under the control of the first boost control signal. Specifically, Figure 3 As shown, the first ends of the first capacitors C32 and C25 are respectively connected to the cathodes of the third diodes D15 and D11, and the second ends jointly receive the first boost control signal CHG_P_P; the first ends of the first capacitors C29 and C23 are respectively connected to the cathodes of the third diodes D11 and D9, and the second ends jointly receive the first sound pressure control signal CHG_P_P.

[0049] In some specific embodiments, the above two groups of first boost control signals CHG_P_P and CHG_N_N are respectively connected to the I / O ports of the battery protection chip known to those skilled in the art, and receive the control signals output through the I / O ports, thereby realizing voltage raising or voltage dropping from the positive electrode B+ of the battery based on different types of control signals.

[0050] 1) Boost state

[0051] When the battery protection chip outputs the first boost control signal to CHG_P_P and CHG_N_N through the I / O port as a PWM signal (generally, the high level of the PWM signal is 3.3V and the low level is 0V), and the two are in an inverse relationship with each other, the first capacitor of each level of the first bootstrap boost sub-circuit first raises the cathode voltage of the third diode of this level to a voltage that is 3.3V higher than its positive electrode minus the voltage drop of the diode itself through the received high-level pulse. When the signal received by the first capacitor of this level becomes a low level, the charge retention function of the first capacitor is used to maintain the cathode of the third diode at this voltage. At this time, the signal received by the first capacitor of the next level of the first bootstrap boost sub-circuit becomes a high level, thereby further raising the voltage at the cathode of the third diode of the next level. Thus, through two sets of alternately input mutually inverse PWM signals, the voltage can be gradually raised from the positive electrode B+ of the battery without providing an additional boost power supply, until the output voltage of the last level of the first bootstrap boost sub-circuit is higher than the threshold voltage.

[0052] As analyzed above, in Figure 3 In the embodiment shown, the difference between the threshold voltage and the voltage of the battery positive electrode B+ is greater than 11V. According to the level of the PWM signal and the voltage drop value of each third diode, it can be determined that the required boost value can be achieved by using a 4-level first bootstrap boost subcircuit. In some other embodiments, a bootstrap boost circuit with a suitable number of levels can also be constructed according to specific boost needs.

[0053] 2) Non-boost state

[0054] When the battery protection chip outputs the first boost control signal to CHG_P_P and CHG_N_N through the I / O port as a DC level, regardless of whether the output is a 0V low level or a 3.3V high level, the charge of the first capacitor cannot be maintained continuously at this time, and eventually the voltage of the battery positive electrode B+ passes through each third diode voltage drop step by step, thereby making the voltage of the high potential end of the first boost circuit lower than the battery positive electrode B+.

[0055] The implementation of the first boost circuit 100 is described in detail above. Figure 3As shown, the second boost circuit 200 can adopt a similar circuit. Specifically, the second boost circuit includes a plurality of second bootstrap boost sub-circuits connected in series, and each second bootstrap boost sub-circuit includes a fourth diode and a second capacitor; the anode of the fourth diode of each second bootstrap boost sub-circuit is toward the low potential end of the second boost circuit 200, and the cathode is toward the high potential end of the second boost circuit 200; the anode of the second capacitor of each second bootstrap boost sub-circuit is connected to the cathode of the fourth diode of the second bootstrap boost sub-circuit of the same level, and the cathode is used to receive the second boost control signal ( Figure 3 DSG_P_P and DSG_N_N); each second self-boosting boost subcircuit adjusts its boost amplitude under the control of the second boost control signal. The positive electrode of D10 in the last second self-boosting boost subcircuit is connected to the second control terminal of the charge-discharge switching circuit 300 as the high potential end of the second boost circuit 200. In some preferred embodiments, as Figure 3 As shown, a diode D8 is connected in series between D10 and the second control terminal of the charge-discharge switching circuit 300 .

[0056] Among them, when the second boost control signals DSG_P_P and DSG_N_N are PWM signals, and the second boost control signals DSG_P_P and DSG_N_N received by any two adjacent second bootstrap boost sub-circuits are inverted, the voltage at the high potential end of the second boost circuit 200 is higher than the threshold voltage; when the second boost control signals DSG_P_P and DSG_N_N are DC signals, the voltage at the high potential end of the second boost circuit 200 is lower than the voltage of the battery positive electrode B+.

[0057] In some preferred embodiments, Figure 3 As shown, a current limiting resistor R46 is also connected in series between the second control terminal and the ground terminal of the charge and discharge control circuit. The current limiting resistor R46 ensures that when the battery is not allowed to discharge and the second boost circuit 200 is not working, the G pole of the second NMOS tube Q2 is at a stable low level to avoid its suspension causing damage to the second NMOS tube.

[0058] <Discharge protection circuit>

[0059] like Figure 3 As shown, since the charge and discharge control circuit of the present application adopts a high-end control method, the first potential end of the second boost circuit is connected to the battery positive electrode B+. Therefore, when the second boost control signal is a DC signal, the discharge current path is disconnected. There is still a current path from the high potential end of the second boost circuit 200 through the resistor R25 to the charge and discharge positive electrode P+. At this time, the battery positive electrode B+ may still be charged with the charge and discharge positive electrode C+ / P+ after the voltage drop of the multi-stage fourth diode.

[0060] To this end, in a preferred embodiment of the present application, Figure 3 As shown, the charge and discharge control circuit also includes a discharge protection circuit 400, which is used to control the on / off between the high potential end of the second boost circuit 200 and the charge and discharge positive electrode C+ / P+. Specifically, the discharge protection circuit 400 includes a first optical coupler J2 and a first resistor R52; wherein the negative electrode of the first optical coupler J2 is connected to the first end of the first resistor R52; the first output end is connected to the high potential end of the second boost circuit 200, and the second output end is connected to the charge and discharge positive electrode C+ / P+.

[0061] When the difference between the voltage of the positive electrode of the first optical coupler J2 and the voltage of the second end of the first resistor R52 exceeds the second threshold voltage, the first optical coupler J2 is turned on, otherwise the first optical coupler J2 is turned off, thereby achieving discharge protection.

[0062] In some optional embodiments, such as Figure 3 As shown, the second end of the first resistor R52 is grounded, and the positive electrode of the first optical coupler J2 is connected to the signal DSG_EN output by the battery protection chip. Only when DSG_EN is at a high level, J2 is turned on.

[0063] Figure 5 Some other preferred embodiments of the charge and discharge control circuit are provided. Figure 5 The charge and discharge control circuit provided is Figure 3 The difference is that the discharge protection circuit 500 is used for discharge protection. Specifically, in the discharge protection circuit 500, the positive electrode of the first optical coupler J2 and the second end of the first resistor R52 are respectively connected to any fourth diode (such as Figure 4 D10 in the negative and positive electrodes are connected, using Figure 5 In the discharge protection mode shown, when the second bootstrap boost sub-circuits of each level of the second boost circuit are in a stable boost state through the control of the interval inverted PWM signal, the voltage drawn from both ends of the fourth diode of any level thereof can definitely turn on the first optocoupler J2. On the contrary, when the second boost control signal is a DC signal, both ends of any fourth diode cannot be boosted, so that the first optocoupler J2 can be disconnected synchronously. By using the above-mentioned discharge protection circuit 500, the discharge protection can be synchronously realized by using the characteristics of the bootstrap boost circuit without adding additional control signals.

[0064] In some preferred embodiments, Figure 6 As shown, the above two forms of discharge protection circuits can also be combined to achieve both logic control based on the MCU or battery protection chip and protection of the discharge process based on the state of the boost circuit.

[0065] 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 for controlling the charging and discharging of a battery, wherein the negative electrode of the battery is connected to the negative electrode of the charge and discharge of the same port, Features: It includes a first boost circuit, a second boost circuit and a charge-discharge switching circuit connected in series between the positive electrode of the battery and the charge-discharge positive electrode of the same port; The low potential ends of the first boost circuit and the second boost circuit are both connected to the positive electrode of the battery; The first control terminal of the charge-discharge switching circuit is connected to the high potential terminal of the first boost circuit, and the second control terminal is connected to the high potential terminal of the second boost circuit; The charge-discharge switching circuit conducts a current path from the positive electrode of the battery to the charge-discharge positive electrode when the voltage at the high potential end of the first boost circuit is higher than a preset threshold voltage, and conducts a current path from the charge-discharge positive electrode to the positive electrode of the battery when the voltage at the high potential end of the second boost circuit is higher than the threshold voltage; The charge-discharge switching circuit includes a first NMOS transistor, a second NMOS transistor, a first diode and a second diode; The S pole of the first NMOS tube and the anode of the first diode are both connected to the anode of the battery; The D pole of the first NMOS tube is connected to the D pole of the second NMOS tube; The cathode of the first diode is connected to the cathode of the second diode; The S pole of the second NMOS tube and the anode of the second diode are both connected to the charging and discharging anode; The G pole of the first NMOS tube is the first control terminal, and the G pole of the second NMOS tube is the second control terminal; The first boost circuit comprises a plurality of first self-boosting boost sub-circuits connected in series, each first self-boosting boost sub-circuit comprising a third diode and a first capacitor; The anode of the third diode of each first bootstrap boost sub-circuit is directed toward the low potential end of the first boost circuit, and the cathode is directed toward the high potential end of the first boost circuit; The positive electrode of the first capacitor of each first bootstrap boost subcircuit is connected to the negative electrode of the third diode of the first bootstrap boost subcircuit of the same level, and the negative electrode is used to receive the first boost control signal; The first bootstrap boost subcircuit of each stage adjusts its boost amplitude under the control of the first boost control signal; The second boost circuit comprises a plurality of second bootstrap boost sub-circuits connected in series, each second bootstrap boost sub-circuit comprising a fourth diode and a second capacitor; The anode of the fourth diode of each second bootstrap boost sub-circuit is directed toward the low potential end of the second boost circuit, and the cathode is directed toward the high potential end of the second boost circuit; The positive electrode of the second capacitor of each stage of the second bootstrap boost sub-circuit is connected to the negative electrode of the fourth diode of the second bootstrap boost sub-circuit of the stage, and the negative electrode is used to receive the second boost control signal; Each stage of the second bootstrap boost sub-circuit adjusts its boost amplitude under the control of the second boost control signal.

2. The charge and discharge control circuit according to claim 1, Features: The difference between the threshold voltage and the voltage of the positive electrode of the battery is greater than 11V.

3. The charge and discharge control circuit according to claim 1, Features: When the first boost control signal is a PWM signal, and the first boost control signals received by any two adjacent first bootstrap boost sub-circuits are inverted, the voltage at the high potential end of the first boost circuit is higher than the threshold voltage; When the first boost control signal is a DC signal, the voltage at the high potential end of the first boost circuit is lower than the voltage of the positive electrode of the battery.

4. The charge and discharge control circuit according to claim 1, Features: When the second boost control signal is a PWM signal, and the second boost control signals received by any two adjacent second bootstrap boost sub-circuits are inverted, the voltage at the high potential end of the second boost circuit is higher than the threshold voltage; When the second boost control signal is a DC signal, the voltage at the high potential end of the second boost circuit is lower than the voltage of the positive electrode of the battery.

5. The charge and discharge control circuit according to claim 1, Features: It also includes a discharge protection circuit for controlling the connection and disconnection between the high potential end of the second boost circuit and the charge and discharge positive electrode.

6. The charge and discharge control circuit according to claim 5, Features: The discharge protection circuit includes a first optical coupler and a first resistor; The negative electrode of the first optical coupler is connected to the first end of the first resistor; the first output end is connected to the high potential end of the second boost circuit, and the second output end is connected to the charging and discharging positive electrode.

7. The charge and discharge control circuit according to claim 6, Features: The anode of the first optical coupler and the second end of the first resistor are respectively connected to the cathode and anode of any fourth diode.

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