Lithium battery charging control circuit with activation function and method

Abstract

The invention discloses a lithium battery charging control circuit and method with an activation function, and belongs to the technical field of power electronics. The circuit comprises a current detection circuit, a charge pump circuit, a bootstrap circuit, a charging current control and protection circuit, a driving circuit, a voltage detection circuit, a high-voltage side driving circuit DRVH, a resistor R1, an inductor L1, a capacitor C1, a power tube module M1, a power tube M2 and a switch SW. In the scheme, the voltage detection circuit selects different voltage division proportions through the input section number selection signal, so that the detection of the battery voltage, the activation of charging, the linear constant-current charging and the stopping of charging after the battery is fully charged are realized. According to the method, different numbers of lithium batteries can be charged based on the circuit, and trickle activation charging can also be carried out on the ultra-low-voltage lithium battery. According to the invention, the problem that compatible charging and ultralow-voltage activation are difficult to realize when the number of batteries is different is solved.

Description

Technical Field

[0001] The invention belongs to the technical field of power electronics, and in particular relates to a lithium battery charging control circuit and method with an activation function. Background Art

[0002] Lithium-ion batteries are electrochemical energy storage systems with high energy density and good comprehensive performance, and are widely used in various portable electronic devices. However, due to the wide variety of portable devices, the operating voltages are different, and the lithium battery systems used are also different, ranging from single cells to multiple cells in series. Different devices need to be equipped with different charging adapters, resulting in a wide variety of adapters, which is very inconvenient.

[0003] The current fast charging protocol has been widely used, and the 5V power interface is common. However, the current lithium battery charging system using 5V power supply is basically only applicable to one scenario. For example, Figure 1 As shown, one battery adopts linear charging method; Figure 2 As shown in the figure, boost charging is used for batteries with more than one cell. Since the voltage of one cell is less than 5V, and the voltage of multiple cells connected in series is higher than 5V, linear or boost charging alone cannot be compatible with these two scenarios, and cannot be effectively activated at ultra-low voltage. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the present invention provides a lithium battery charging control circuit and method with activation function, which solves the problem that it is difficult to achieve compatible charging and ultra-low voltage activation when the number of battery cells is different.

[0005] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is:

[0006] On the one hand, the present invention provides a lithium battery charging control circuit with activation function, including a current detection circuit, a charge pump circuit, a bootstrap circuit, a charging current control and protection circuit, a drive circuit, a voltage detection circuit, a high-voltage side drive circuit DRVH, a resistor R1, an inductor L1, a capacitor C1, a power tube module M1, a power tube M2 and a switch SW;

[0007] One end of the resistor R1 is connected to the first power input end and the first input end of the current detection circuit; the other end of the resistor R1 is respectively connected to the second input end of the current detection circuit and one end of the inductor L1; the output end of the current detection circuit is respectively connected to the current input end of the charge pump circuit and the charging current control and protection circuit; the other end of the inductor L1 is respectively connected to one end of the capacitor C1, the first drain of the power tube module M1 and the drain of the power tube M2; the source of the power tube M2 is respectively connected to the second power input end and the negative electrode of the battery; the positive electrode of the battery is respectively connected to the second drain of the power tube module M1 and the voltage input end of the voltage detection circuit; The gate is connected to the output end of the high-voltage side drive circuit DRVH; the input end of the high-voltage side drive circuit DRVH is respectively connected to the moving end of the switch S2 and the other end of the capacitor C1; the voltage output end of the voltage detection circuit is connected to the voltage input end of the charging current control and protection circuit; the voltage detection circuit is externally connected to a battery cell number selection signal; the switch control end of the voltage detection circuit is connected to the switch SW; the first fixed end of the switch SW is connected to the output end of the charge pump circuit; the second fixed end of the switch SW is connected to the bootstrap circuit; the output end of the charging current control and protection circuit is connected to the input end of the drive circuit; the output end of the drive circuit is connected to the gate of the power tube M2.

[0008] The beneficial effects of the present invention are as follows: a lithium battery charging control circuit with an activation function provided by the present invention can operate in a linear constant current mode when the battery voltage is less than a preset voltage threshold, and can operate in a boost mode when the battery voltage exceeds the preset voltage threshold. It can automatically switch the charging mode and can be perfectly applied to charging problems with different numbers of batteries, and also has a trickle activation function when the battery voltage is ultra-low.

[0009] On the other hand, the present invention also provides a charging control method based on a lithium battery charging control circuit with an activation function, comprising the following steps:

[0010] When the voltage detection circuit detects that the battery voltage is lower than the preset total battery voltage and lower than the preset voltage threshold, the active end of the switch SW is connected to the first fixed end, and the output of the charge pump circuit activates and charges the battery through the capacitor C1, wherein the preset total battery voltage is the product of the preset single-cell battery voltage multiplied by the number of battery cells;

[0011] When the voltage detection circuit detects that the battery voltage is higher than the preset total battery voltage and lower than the preset voltage threshold, the moving end of the switch SW is connected to the first fixed end, and the charge pump circuit adjusts the output voltage according to the charging current detected by the current detection circuit. The output voltage of the charge pump circuit controls the opening degree of the power tube module M1 through the high-voltage side drive circuit DRVH to perform linear constant current charging on the battery;

[0012] When the voltage detection circuit detects that the battery voltage is higher than the preset voltage threshold, the moving end of the switch SW is connected to the second fixed end, and the charging current control and protection circuit controls the on and off of the power tube M2 through the driving circuit according to the charging current detected by the current detection circuit. At the same time, the bootstrap circuit controls the on and off of the power tube M1 and the power tube M2 in a complementary state, so that the charging current reaches the maximum. When the battery is fully charged, the voltage detection circuit outputs a stop signal to the charging current control and protection circuit to stop charging.

[0013] The beneficial effects of the present invention are as follows: the present invention provides a charging control method based on a lithium battery charging control circuit with an activation function, which controls the charging of a lithium battery based on the above-mentioned lithium battery charging control circuit with an activation function. This scheme detects the battery voltage to switch between a charge pump circuit or a bootstrap circuit for charging, thereby realizing autonomous switching between linear constant current and boost conversion. At the same time, the linear constant current can also adjust the output current according to the battery voltage to realize the functions of activating the battery and large current cross-current charging.

[0014] Other advantages of the present invention will be analyzed in more detail in subsequent embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0016] Figure 1 This is a circuit schematic diagram of a lithium battery charging control circuit with activation function in Example 1 of the present invention.

[0017] Figure 2 4 is a circuit schematic diagram of the current detection circuit in Example 1 of the present invention.

[0018] Figure 3 4 is a circuit schematic diagram of the charge pump circuit in Example 1 of the present invention.

[0019] Figure 4 4 is a circuit schematic diagram of the high-voltage side driving circuit DRVH in Embodiment 1 of the present invention.

[0020] Figure 5 This is a circuit schematic diagram of the bootstrap power supply circuit in Example 1 of the present invention. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents the selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present invention.

[0022] like Figure 1 As shown, in one embodiment of the present invention, the present invention provides a lithium battery charging control circuit with an activation function, including a current detection circuit, a charge pump circuit, a bootstrap circuit, a charging current control and protection circuit, a drive circuit, a voltage detection circuit, a high-voltage side drive circuit DRVH, a resistor R1, an inductor L1, a capacitor C1, a power tube module M1, a power tube M2 and a switch SW;

[0023] One end of the resistor R1 is connected to the first power input end and the first input end of the current detection circuit; the other end of the resistor R1 is respectively connected to the second input end of the current detection circuit and one end of the inductor L1; the output end of the current detection circuit is respectively connected to the current input end of the charge pump circuit and the charging current control and protection circuit; the other end of the inductor L1 is respectively connected to one end of the capacitor C1, the first drain of the power tube module M1 and the drain of the power tube M2; the source of the power tube M2 is respectively connected to the second power input end and the negative electrode of the battery; the positive electrode of the battery is respectively connected to the second drain of the power tube module M1 and the voltage input end of the voltage detection circuit; The gate is connected to the output end of the high-voltage side drive circuit DRVH; the input end of the high-voltage side drive circuit DRVH is respectively connected to the moving end of the switch S2 and the other end of the capacitor C1; the voltage output end of the voltage detection circuit is connected to the voltage input end of the charging current control and protection circuit; the voltage detection circuit is externally connected to a battery cell number selection signal; the switch control end of the voltage detection circuit is connected to the switch SW; the first fixed end of the switch SW is connected to the output end of the charge pump circuit; the second fixed end of the switch SW is connected to the bootstrap circuit; the output end of the charging current control and protection circuit is connected to the input end of the drive circuit; the output end of the drive circuit is connected to the gate of the power tube M2.

[0024] In this solution, the power tube module M1 is composed of two power tubes with connected sources and connected gates, wherein the drain of one power tube serves as the first drain of the power tube module M1, the drain of the other power tube serves as the second drain of the power tube module M1, and the two power tube gates are connected to serve as the gate of the power tube module M1. In this solution, the resistor R1 serves as a current detection resistor.

[0025] like Figure 2 As shown, the current detection circuit includes a resistor R3, a resistor R4, a resistor R5, a power tube M3, a power tube M4, a power tube M5, a power tube M6, a power tube M7, a power tube M8, a power tube M9, a power tube M10 and a power tube M11, wherein the resistance value of the resistor R3 is equal to that of the resistor R4;

[0026] One end of the resistor R3 is connected to one end of the resistor R1 as the first input end of the current detection circuit; the other end of the resistor R3 is connected to the source of the power tube M3 and the source of the power tube M5 respectively; one end of the resistor R4 is connected to the second input end of the current detection circuit and the other end of the resistor R1; the other end of the resistor R4 is connected to the source of the power tube M4; the gate of the power tube M3 is connected to its drain, the gate of the power tube M4 and the drain of the power tube M6 respectively; the drain of the power tube M4 is connected to the gate of the power tube M5 and the drain of the power tube M7 respectively; the drain of the power tube M5 is connected to the drain of the power tube M8; the gate of the power tube M6 is connected to the drain of the power tube M6; the drain of the power tube M6 is connected to the drain of the power tube M7; the drain of the power tube M7 is connected to the drain of the power tube M8; the gate of the power tube M6 is connected to the drain of the power tube M8; the gate of the power tube M6 is connected to the drain of the power tube M5; the drain of the power tube M6 is connected to the drain of the power tube M8; the gate of the power tube M6 is connected to the drain of the power tube M6 ... The gate of the power tube M7 and the gate of the power tube M8 are all externally connected to the power supply VCC; the source of the power tube M6 is connected to the drain of the power tube M9; the source of the power tube M7 is connected to the drain of the power tube M10; the source of the power tube M8 is respectively connected to one end of the resistor R5, the charging current control and protection circuit and the charge pump circuit, and serves as the output end of the current detection circuit; the other end of the resistor R5 is respectively connected to the source of the power tube M10, the source of the power tube M9 and the source of the power tube M11, and is grounded; the gate of the power tube M10 is respectively connected to the gate of the power tube M9, the gate and the drain of the power tube M11, and is externally connected to the bias current ibias.

[0027] The current detection circuit provided in this solution is a differential input circuit. After the bias current ibias is input, the voltage signal with a common mode voltage not equal to 0 can be converted into a voltage signal relative to the ground. The power tube M9 and the power tube M10 form a current mirror structure, so that the current passing through the power tube M3 and the power tube M4 are equal. Since the resistance values ​​of the resistor R3 and the resistor R4 are equal, the voltage at point A is equal to the voltage at point B. The calculation expressions of the current values ​​flowing through the resistors R3 and R4 are as follows:

[0028] ,

[0029] ,

[0030] in, represents the current value flowing through resistor R3, represents the voltage at the first input terminal of the current detection circuit, represents the voltage value at point A, represents the resistance value of resistor R3, represents the current value flowing through resistor R4, represents the voltage at the second input terminal of the current detection circuit, represents the voltage value at point B, Indicates the resistance value of resistor R4;

[0031] The current flowing through the resistor R5 is the difference between the current flowing through the resistor R3 and the current flowing through the resistor R4. The voltage value on the resistor R5, that is, the detection output voltage at the output end of the current detection circuit, is calculated as follows:

[0032] ,

[0033] in, represents the resistance value of resistor R5, Indicates the detection output voltage value at the output end of the current detection circuit.

[0034] It can be found that the current detection circuit provided by the present invention only amplifies the voltage V IN and V SNS The difference is independent of the common-mode voltage of the input signal.

[0035] like Figure 3 As shown, the charge pump circuit includes an error amplifier E1, a unit gain amplifier E2, a capacitor C2, a capacitor C3, a diode D1, a diode D2 and a square wave generating circuit;

[0036] The first end of the error amplifier E1 is externally connected to a preset reference voltage; the second end of the error amplifier E1 is connected to one end of the resistor R5; the third end of the error amplifier E1 is respectively connected to one end of the capacitor C2 and the first end of the unit gain amplifier E2; the other end of the capacitor C2 is grounded; the third end of the unit gain amplifier E2 is respectively connected to the second end of the unit gain amplifier E2 and the positive electrode of the diode D1; the cathode of the diode D1 is respectively connected to one end of the capacitor C3 and the positive electrode of the diode D2; the other end of the capacitor C3 is connected to the square wave generating circuit; the cathode of the diode D2 is connected to the first fixed end of the switch SW.

[0037] In this embodiment, the first and second terminals of the error amplifier E1 are respectively connected to the preset reference voltage and the detection output voltage of the current detection circuit. Based on the current flowing through the current detection resistor, the detection output voltage is compared with the reference voltage, and the error is amplified to obtain the voltage V1. The square wave generator in the square wave generating circuit generates a square wave with an amplitude of V2. The signal is loaded on the negative terminal of the capacitor C3. When the square wave signal is low, the follower output charges the capacitor C3 through the diode; when the square wave signal is high, the capacitor C3 charges the capacitor C1. One end of the capacitor C1, that is, the positive end voltage of the capacitor C1 is equal to V1+V2. The positive end of the capacitor C1 is connected to the gate of the power tube module M1 to maintain the power tube module M1 in a conducting state and the current is constant. If the charging current exceeds the set current, the output voltage of the error amplifier E1 decreases, that is, V1 decreases, and the gate voltage of the power tube module M1 decreases; and if the charging current is less than the set current, the output voltage of the error amplifier E1 increases, that is, V1 increases, and the gate voltage of the power tube module M1 increases, thereby keeping the charging current of the battery at a constant value.

[0038] like Figure 4 As shown, the high-voltage side driving circuit DRVH includes an AND gate A1, an AND gate A2, an inverter N1, an inverter N2, a buffer B1, a buffer B2, a power tube M12, a power tube M13 and a power tube M14;

[0039] One input end of the AND gate A1 is connected to one end of the inverter N1 and is externally connected to a high-voltage drive input signal; the other input end of the AND gate A1 is connected to the output end of the buffer B2, the gate of the power tube M13 and the gate of the power tube M14; the output end of the AND gate A1 is connected to the input end of the inverter N1; the output end of the inverter N1 is connected to the input end of the buffer B1; the output end of the buffer B1 is respectively connected to the gate of the power meter M12 and one input end of the AND gate A2; the other input end of the AND gate A2 The end is connected to the output end of the inverter N2; the output end of the AND gate A2 is connected to the input end of the buffer B2; the source of the power tube M12 serves as the input end of the high-voltage side driving circuit DRVH, and is respectively connected to one end of the capacitor C1 and the moving end of the switch SW; the drain of the power tube M12 is connected to the source of the power tube M13; the drain of the power tube M13 is connected to the drain of the power tube M14; the source of the power tube M14 serves as the output end of the high-voltage side driving circuit DRVH, and is connected to the gate of the power tube module M1.

[0040] In this solution, the high-voltage side drive circuit DRVH forms a non-overlapping phase circuit through an AND gate, an inverter and a buffer, thereby ensuring that the NMOS power tube and the PMOS power tube are not turned on at the same time, and the buffer B1 and the buffer B2 are cascaded reverse logic circuits, and the driving energy capacity increases step by step, thereby ensuring that the NMOS power tube and the PMOS power tube of the output stage can be quickly turned on or off; the pull-down tube in this embodiment uses two NMOS tubes connected back to back, namely, the power tube M13 and the power tube M14, the purpose of which is to prevent the charge stored on the capacitor C1 from leaking due to the parasitic diode of the MOS tube in the linear mode.

[0041] like Figure 5 As shown, the bootstrap power supply circuit includes a MOS tube M15, a level shift circuit, a loop control circuit and a low-voltage side drive circuit DRVL;

[0042] The drain of the power tube M15 is connected to an external power supply VCC; the source of the power tube M15 is connected to one end of the capacitor C1; the gate of the power tube M15 is connected to the first end of the level shift circuit; the loop control circuit is respectively connected to the two ends of the level shift circuit and the first end of the low-voltage side drive circuit DRVL; the third end of the level shift circuit is respectively connected to the other end of the capacitor C1 and the drain of the power tube M2; the second end of the low-voltage side drive circuit DRVL is connected to the gate of the power tube M2; the source of the power tube M2 is connected to the third end of the low-voltage side drive circuit DRVL and is grounded.

[0043] The loop control circuit outputs a square wave signal and is connected to the level shift circuit and the low-voltage side drive circuit DRVL respectively; when the square wave signal is high, the low-voltage side drive circuit turns on the power tube M2, then the LX point voltage is pulled down to 0, and the level shift circuit drives the power tube M15 to turn on to charge the capacitor C1; when the square wave signal is low, the power tube M2 is turned off, then the LX point voltage rises, and at the same time, the level shift circuit drives the power tube M15 to turn off, and the voltage across the capacitor C1 is maintained at 5V, thereby supplying power to the drive circuit of M1, that is, the high-voltage side drive circuit DRVH.

[0044] Embodiment 2:

[0045] On the basis of Example 1, the present invention provides a charging control method based on a lithium battery charging control circuit with an activation function, comprising the following steps:

[0046] If the voltage detection circuit detects that the battery voltage is lower than the preset total battery voltage and lower than the preset voltage threshold, the active end of the switch SW is connected to the first fixed end, and the output of the charge pump circuit activates and charges the battery through the capacitor C1, wherein the preset total battery voltage is the product of the preset single-cell battery voltage multiplied by the number of battery cells;

[0047] If the voltage detection circuit detects that the battery voltage is higher than the preset total battery voltage and lower than the preset voltage threshold, the moving end of the switch SW is connected to the first fixed end, and the charge pump circuit adjusts the output voltage according to the charging current detected by the current detection circuit. The output voltage of the charge pump circuit controls the opening degree of the power tube module M1 through the high-voltage side drive circuit DRVH to perform linear constant current charging on the battery;

[0048] If the voltage detection circuit detects that the battery voltage is higher than the preset voltage threshold, the moving end of the switch SW is connected to the second fixed end, and the charging current control and protection circuit controls the on and off of the power tube M2 through the driving circuit according to the charging current detected by the current detection circuit. At the same time, the bootstrap circuit controls the on and off of the power tube M1 and the power tube M2 in a complementary state, so that the charging current reaches the maximum. When the battery is fully charged, the voltage detection circuit outputs a stop signal to the charging current control and protection circuit to stop charging.

[0049] In this solution, the voltage detection circuit selects different voltage division ratios according to the input cell number selection signal, thereby realizing the detection of battery voltage; the current when the battery is activated and charged is very small; the power tube 1 and the power tube M2 are complementary in state, which means that when the power tube M1 is in the on state, the power tube M2 is in the off state, and when the power tube M1 is in the off state, the power tube M2 is in the on state, so that; in this embodiment, the preset single-cell battery voltage is 1.5V, and the preset voltage threshold is 5V.

[0050] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A lithium battery charging control circuit with activation function, characterized in that: It includes a current detection circuit, a charge pump circuit, a bootstrap circuit, a charging current control and protection circuit, a drive circuit, a voltage detection circuit, a high-voltage side drive circuit DRVH, a resistor R1, an inductor L1, a capacitor C1, a power tube module M1, a power tube M2 and a switch SW; One end of the resistor R1 is connected to the first power input end and the first input end of the current detection circuit; the other end of the resistor R1 is respectively connected to the second input end of the current detection circuit and one end of the inductor L1; the output end of the current detection circuit is respectively connected to the current input end of the charge pump circuit and the charging current control and protection circuit; the other end of the inductor L1 is respectively connected to one end of the capacitor C1, the first drain of the power tube module M1 and the drain of the power tube M2; the source of the power tube M2 is respectively connected to the second power input end and the negative electrode of the battery; the positive electrode of the battery is respectively connected to the second drain of the power tube module M1 and the voltage input end of the voltage detection circuit; The gate is connected to the output end of the high-voltage side drive circuit DRVH; the input end of the high-voltage side drive circuit DRVH is respectively connected to the moving end of the switch S2 and the other end of the capacitor C1; the voltage output end of the voltage detection circuit is connected to the voltage input end of the charging current control and protection circuit; the voltage detection circuit is externally connected to a battery cell number selection signal; the switch control end of the voltage detection circuit is connected to the switch SW; the first fixed end of the switch SW is connected to the output end of the charge pump circuit; the second fixed end of the switch SW is connected to the bootstrap circuit; the output end of the charging current control and protection circuit is connected to the input end of the drive circuit; the output end of the drive circuit is connected to the gate of the power tube M2.

2. The lithium battery charging control circuit with activation function according to claim 1, characterized in that: The current detection circuit includes a resistor R3, a resistor R4, a resistor R5, a power tube M3, a power tube M4, a power tube M5, a power tube M6, a power tube M7, a power tube M8, a power tube M9, a power tube M10 and a power tube M11, wherein the resistance value of the resistor R3 is equal to that of the resistor R4; One end of the resistor R3 is connected to one end of the resistor R1 as the first input end of the current detection circuit; the other end of the resistor R3 is connected to the source of the power tube M3 and the source of the power tube M5 respectively; one end of the resistor R4 is connected to the second input end of the current detection circuit and the other end of the resistor R1; the other end of the resistor R4 is connected to the source of the power tube M4; the gate of the power tube M3 is connected to its drain, the gate of the power tube M4 and the drain of the power tube M6 respectively; the drain of the power tube M4 is connected to the gate of the power tube M5 and the drain of the power tube M7 respectively; the drain of the power tube M5 is connected to the drain of the power tube M8; the gate of the power tube M6 is connected to the drain of the power tube M6; the drain of the power tube M6 is connected to the drain of the power tube M7; the drain of the power tube M7 is connected to the drain of the power tube M8; the gate of the power tube M6 is connected to the drain of the power tube M8; the gate of the power tube M6 is connected to the drain of the power tube M5; the drain of the power tube M6 is connected to the drain of the power tube M8; the gate of the power tube M6 is connected to the drain of the power tube M6 ... The gate of the power tube M7 and the gate of the power tube M8 are all externally connected to the power supply VCC; the source of the power tube M6 is connected to the drain of the power tube M9; the source of the power tube M7 is connected to the drain of the power tube M10; the source of the power tube M8 is respectively connected to one end of the resistor R5, the charging current control and protection circuit and the charge pump circuit, and serves as the output end of the current detection circuit; the other end of the resistor R5 is respectively connected to the source of the power tube M10, the source of the power tube M9 and the source of the power tube M11, and is grounded; the gate of the power tube M10 is respectively connected to the gate of the power tube M9, the gate and the drain of the power tube M11, and is externally connected to the bias current ibias.

3. The lithium battery charging control circuit with activation function according to claim 2, characterized in that: The charge pump circuit includes an error amplifier E1, a unit gain amplifier E2, a capacitor C2, a capacitor C3, a diode D1, a diode D2 and a square wave generating circuit; The first end of the error amplifier E1 is externally connected to a preset reference voltage; the second end of the error amplifier E1 is connected to one end of the resistor R5; the third end of the error amplifier E1 is respectively connected to one end of the capacitor C2 and the first end of the unit gain amplifier E2; the other end of the capacitor C2 is grounded; the third end of the unit gain amplifier E2 is respectively connected to the second end of the unit gain amplifier E2 and the positive electrode of the diode D1; the cathode of the diode D1 is respectively connected to one end of the capacitor C3 and the positive electrode of the diode D2; the other end of the capacitor C3 is connected to the square wave generating circuit; the cathode of the diode D2 is connected to the first fixed end of the switch SW.

4. The lithium battery charging control circuit with activation function according to claim 3, characterized in that: The high-voltage side driving circuit DRVH includes an AND gate A1, an AND gate A2, an inverter N1, an inverter N2, a buffer B1, a buffer B2, a power tube M12, a power tube M13 and a power tube M14; One input end of the AND gate A1 is connected to one end of the inverter N1 and is externally connected to a high-voltage drive input signal; the other input end of the AND gate A1 is connected to the output end of the buffer B2, the gate of the power tube M13 and the gate of the power tube M14; the output end of the AND gate A1 is connected to the input end of the inverter N1; the output end of the inverter N1 is connected to the input end of the buffer B1; the output end of the buffer B1 is respectively connected to the gate of the power meter M12 and one input end of the AND gate A2; the other input end of the AND gate A2 The end is connected to the output end of the inverter N2; the output end of the AND gate A2 is connected to the input end of the buffer B2; the source of the power tube M12 serves as the input end of the high-voltage side driving circuit DRVH, and is respectively connected to one end of the capacitor C1 and the moving end of the switch SW; the drain of the power tube M12 is connected to the source of the power tube M13; the drain of the power tube M13 is connected to the drain of the power tube M14; the source of the power tube M14 serves as the output end of the high-voltage side driving circuit DRVH, and is connected to the gate of the power tube module M1.

5. The lithium battery charging control circuit with activation function according to claim 4, characterized in that: The bootstrap power supply circuit includes a MOS tube M15, a level shift circuit, a loop control circuit and a low-voltage side drive circuit DRVL; The drain of the power tube M15 is connected to an external power supply VCC; the source of the power tube M15 is connected to one end of the capacitor C1; the gate of the power tube M15 is connected to the first end of the level shift circuit; the loop control circuit is respectively connected to the two ends of the level shift circuit and the first end of the low-voltage side drive circuit DRVL; the third end of the level shift circuit is respectively connected to the other end of the capacitor C1 and the drain of the power tube M2; the second end of the low-voltage side drive circuit DRVL is connected to the gate of the power tube M2; the source of the power tube M2 is connected to the third end of the low-voltage side drive circuit DRVL and is grounded.

6. A charging control method for a lithium battery charging control circuit with activation function based on any one of claims 1 to 5, characterized in that: The steps include: When the voltage detection circuit detects that the battery voltage is lower than the preset total battery voltage and lower than the preset voltage threshold, the active end of the switch SW is connected to the first fixed end, and the output of the charge pump circuit activates and charges the battery through the capacitor C1, wherein the preset total battery voltage is the product of the preset single-cell battery voltage multiplied by the number of battery cells; When the voltage detection circuit detects that the battery voltage is higher than the preset total battery voltage and lower than the preset voltage threshold, the moving end of the switch SW is connected to the first fixed end, and the charge pump circuit adjusts the output voltage according to the charging current detected by the current detection circuit. The output voltage of the charge pump circuit controls the opening degree of the power tube module M1 through the high-voltage side drive circuit DRVH to perform linear constant current charging on the battery; When the voltage detection circuit detects that the battery voltage is higher than the preset voltage threshold, the moving end of the switch SW is connected to the second fixed end, and the charging current control and protection circuit controls the on and off of the power tube M2 through the driving circuit according to the charging current detected by the current detection circuit. At the same time, the bootstrap circuit controls the on and off of the power tube M1 and the power tube M2 in a complementary state, so that the charging current reaches the maximum. When the battery is fully charged, the voltage detection circuit outputs a stop signal to the charging current control and protection circuit to stop charging.

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