A lithium battery protection circuit and architecture

Abstract

The present invention discloses a lithium battery protection circuit and architecture, which relates to the field of lithium battery protection, and includes: a lithium battery control chip and a switch chip that are packaged together and arranged one by one; the lithium battery control chip has a resistance adjustment module and a driving resistor; the control end of the lithium battery control chip outputs a control signal to control the conduction timing of the resistance adjustment module, and adjusts the resistance of the driving resistor, and the resistance of the driving resistor is set in direct proportion to the opening time and closing time of the switch chip, so that the driving current output by the driving end of the lithium battery control chip is adapted to the opening and closing time of the switch chip. By combining and packaging a single lithium battery control chip and a single switch chip, different switch chips are selected according to different output current requirements, and the optimal opening and closing time of the switch chip is matched, so as to avoid the problem of easy damage of the switch chip, improve the service life of the device, and also facilitate cost control.

Description

Technical Field

[0001] The present invention relates to the field of lithium battery protection technology, and in particular to a lithium battery protection circuit and architecture. Background Art

[0002] With the development of electronic industry technology, lithium batteries are more and more widely used. As a protection for the charging and discharging of lithium batteries, lithium battery protection boards are also widely used. At present, the commonly used packages of lithium battery protection chips are SOT23-6 or DNF, such as Figure 1 As shown, this packaging method adopts a design in which the lithium battery control chip and the switch chip are separated, that is, a 1+n combination method, where n represents the number of switch chips. As the current demand increases, the n value increases accordingly.

[0003] In actual applications, the electrical parameters of each switch chip are different, resulting in the lithium battery control chip sending out the same control signal. The opening and closing of the switch chips have certain differences and cannot be completely synchronized. Then in the shutdown process, each switch chip has a shutdown sequence, and the last switch chip closed will bear all the current of the circuit. This current far exceeds the maximum current allowed by the switch chip itself. In this way, the switch chip is easily damaged, and at the moment of shutdown, the impact current generated by the system will also cause the last switch chip closed to break down, thereby reducing the service life of the lithium battery protection board and posing a safety hazard.

[0004] Therefore, the existing technology still needs to be improved and developed. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a lithium battery protection circuit and architecture in response to the above-mentioned defects of the prior art, aiming to solve the problem that the existing lithium battery protection board has inconsistent control over the switch chip, causing the switch chip to be easily damaged and reducing the service life of the protection board.

[0006] In a first aspect, the present application provides a lithium battery protection circuit, which adopts the following technical solution:

[0007] A lithium battery protection circuit is packaged on a lithium battery protection board and is used to protect the charging and discharging of lithium batteries, comprising:

[0008] The lithium battery control chip and the switch chip are packaged together and arranged one by one;

[0009] The lithium battery control chip has a resistance adjustment module and a driving resistor;

[0010] The resistance adjustment module is respectively connected to the control end of the lithium battery control chip and one end of the driving resistor, the other end of the driving resistor is connected to the control end of the switch chip, and the other end of the driving resistor serves as the driving end of the lithium battery control chip;

[0011] The control end of the lithium battery control chip outputs a control signal to control the conduction timing of the resistance adjustment module, thereby adjusting the resistance of the driving resistor. The resistance of the driving resistor is set in direct proportion to the opening time and closing time of the switch chip, so that the driving current output by the driving end of the lithium battery control chip is adapted to the opening and closing time of the switch chip.

[0012] Furthermore, the resistance adjustment module includes a first adjustment unit and a second adjustment unit, wherein the input ends of the first adjustment unit and the second adjustment unit are connected to the control end of the lithium battery control chip, the output ends of the first adjustment unit and the second adjustment unit are connected to the driving resistor, and the first adjustment unit and the second adjustment unit are used to adjust the resistance of the driving resistor according to the control signal of the lithium battery control chip.

[0013] Further, the first regulating unit includes a first AND gate, a second AND gate, a third AND gate, a fourth AND gate, a first MOS tube, a second MOS tube, a third MOS tube and a fourth MOS tube, the driving resistor includes a first driving resistor, a second driving resistor, a third driving resistor and a fourth driving resistor, the first input end of the first AND gate is connected to the A0 end of the lithium battery control chip, the second input end of the first AND gate is connected to the AN end of the lithium battery control chip, the output end of the first AND gate is connected to the gate of the first MOS tube, the drain of the first MOS tube is connected to one end of the first resistor, the other end of the first resistor is connected to the output end, and the source of the first MOS tube is grounded;

[0014] The first input end of the second AND gate is connected to the A1 end of the lithium battery control chip, the second input end of the second AND gate is connected to the AN end of the lithium battery control chip, the output end of the second AND gate is connected to the gate of the second MOS tube, the drain of the second MOS tube is connected to one end of the second resistor, the other end of the second resistor is connected to the output end, and the source of the second MOS tube is grounded;

[0015] The first input end of the third AND gate is connected to the A2 end of the lithium battery control chip, the second output end of the third AND gate is connected to the AN end of the lithium battery control chip, the output end of the third AND gate is connected to the gate of the third MOS tube, the drain of the third MOS tube is connected to one end of the third resistor, the other end of the third resistor is connected to the output end, and the source of the third MOS tube is grounded;

[0016] The first input end of the fourth AND gate is connected to the A3 end of the lithium battery control chip, the second input end of the fourth AND gate is connected to the AN end of the lithium battery control chip, the output end of the fourth AND gate is connected to the gate of the fourth MOS tube, the drain of the fourth MOS tube is connected to one end of the fourth resistor, the other end of the resistor is connected to the output end, and the source of the fourth MOS tube is grounded.

[0017] Further, the second regulating unit includes a first OR gate, a second OR gate, a third OR gate, a fourth OR gate, a fifth MOS tube, a sixth MOS tube, a seventh MOS tube and an eighth MOS tube, the driving resistor also includes a fifth driving resistor, a sixth driving resistor, a seventh driving resistor and an eighth driving resistor, the first input end of the first OR gate is connected to the B0 end of the lithium battery control chip, the second input end of the first OR gate is connected to the BN end of the lithium battery control chip, the output end of the first OR gate is connected to the gate of the fifth MOS tube, the source of the fifth MOS tube is grounded, the drain of the fifth MOS tube is connected to one end of the fifth resistor, and the other end of the fifth resistor is connected to the output end;

[0018] The first input end of the second OR gate is connected to the B1 end of the lithium battery control chip, the second input end of the second OR gate is connected to the BN end of the lithium battery control chip, the output end of the second OR gate is connected to the gate of the sixth MOS tube, the source of the sixth MOS tube is grounded, the drain of the sixth MOS tube is connected to one end of the sixth resistor, and the other end of the sixth resistor is connected to the output end;

[0019] The first input end of the third OR gate is connected to the B2 end of the lithium battery control chip, the second input end of the third OR gate is connected to the BN end of the lithium battery control chip, the output end of the third OR gate is connected to the gate of the seventh MOS tube, the source of the seventh MOS tube is grounded, the drain of the seventh MOS tube is connected to one end of the seventh resistor, and the other end of the seventh resistor is connected to the output end;

[0020] The first input end of the fourth OR gate is connected to the B3 end of the lithium battery control chip, the second input end of the fourth OR gate is connected to the BN end of the lithium battery control chip, the output end of the fourth OR gate is connected to the gate of the eighth MOS tube, the source of the eighth MOS tube is grounded, the drain of the eighth MOS tube is connected to one end of the eighth resistor, and the other end of the eighth resistor is connected to the output end.

[0021] Furthermore, it also includes an anti-reverse module, which is connected to the input end of the lithium battery control chip. The anti-reverse module includes a PMOS tube and an ESD diode. The gate of the PMOS tube is grounded, the drain of the PMOS tube is connected to the positive pole of the power supply, the source of the PMOS tube is connected to the VIN end of the lithium battery control chip, and the ESD diode is connected in parallel with the PMOS tube to the VIN end of the lithium battery control chip.

[0022] Furthermore, the lithium battery control chip has at least five pins, and the at least five pins include a power pin, a ground pin, an overcharge control pin, an over-discharge control pin and a detection pin.

[0023] Furthermore, the switch chip includes a first NMOS tube and a second NMOS tube, the gate of the first NMOS tube is connected to the overcharge pin of the lithium battery control chip, the source of the first NMOS tube is connected to the detection pin of the lithium battery control chip, the drain of the first NMOS tube is connected to the drain of the second NMOS tube, the gate of the second NMOS tube is connected to the over-discharge control pin of the lithium battery control chip, and the source of the second NMOS tube is connected to the ground pin.

[0024] Furthermore, the lithium battery control chip has an input module, a protection module and an output module. The input module includes a reference unit and an oscillation unit. The protection module includes a logic function unit, a charge and discharge protection unit, an undervoltage protection unit, an overvoltage protection unit, an overcurrent protection unit, and a short circuit protection unit. The charge and discharge protection unit, the undervoltage protection unit, the overvoltage protection unit, the overcurrent protection unit, and the short circuit protection unit are all connected to the logic function unit. The output module is used to output a control signal to the control end of the switch chip. Furthermore, the lithium battery control chip can be cascaded with at least one lithium battery.

[0025] In a second aspect, the present application provides a lithium battery protection architecture, which adopts the following technical solutions:

[0026] A lithium battery protection architecture comprises a lithium battery protection board, a packaging body and the lithium battery protection circuit as described above, wherein the lithium battery protection circuit is packaged on the lithium battery protection board through the packaging body.

[0027] Beneficial effects of the present invention: The present invention protects the charging and discharging of lithium batteries through a lithium battery protection board integrated with a lithium battery protection circuit. In specific implementation, the control end of the lithium battery control chip controls the conduction timing of the built-in resistance adjustment module, and controls the resistance of the driving resistor to be proportional to the opening time and closing time of the switch chip, so as to adjust the resistance of the driving resistor, thereby changing the driving current of the control end (gate) of the switch chip, and achieving the adaptation of the driving current to the opening and closing time of the switch chip, thereby achieving the switch chip in the optimal opening and closing time state, and more accurately achieving the control of the switch chip. Therefore, the present application adopts a single chip solution of a lithium battery control chip and a switch chip combination, that is, a lithium battery control chip and a switch chip are both provided, and the lithium battery control chip and the switch chip are packaged together, so there is no need to cascade multiple switch chips, which solves the problem of the switch chip being easily damaged due to inconsistent control of the switch chip, and reduces the volume, improves the service life of the switch chip and the lithium battery protection board, and reduces the cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of multi-chip cascade of an existing single-cell lithium battery protection board.

[0029] Figure 2 It is a connection diagram of the lithium battery control chip and the switch chip provided in an embodiment of the present invention.

[0030] Figure 3 This is an internal block diagram of a single-cell lithium battery control chip provided by an embodiment of the present invention.

[0031] Figure 4 It is a circuit connection diagram of the driving end of the lithium battery control chip provided by an embodiment of the present invention.

[0032] Figure 5 It is a structural schematic diagram of an anti-reverse module at the power input end of a lithium battery control chip provided in an embodiment of the present invention.

[0033] Figure 6 It is a schematic diagram of packaging and wiring of a lithium battery control chip and a switch chip provided in an embodiment of the present invention.

[0034] Figure 7 It is a schematic diagram of the application principle of a single-cell lithium battery control chip provided by an embodiment of the present invention.

[0035] Figure 8 It is a schematic diagram of the front structure of a single-cell lithium battery protection board provided in an embodiment of the present invention.

[0036] Fig. 9 It is a schematic diagram of the back structure of a single-cell lithium battery protection board provided in an embodiment of the present invention.

[0037] Fig.10 It is a schematic diagram of the principle of a very simple periphery of a single-cell lithium battery control chip provided by an embodiment of the present invention.

[0038] Fig.11 It is a schematic diagram of the front structure of the extremely simple periphery of a single-cell lithium battery protection board provided by an embodiment of the present invention.

[0039] Fig.12 It is a schematic diagram of the back structure of the extremely simple periphery of a single-cell lithium battery protection board provided in an embodiment of the present invention.

[0040] Fig.13 It is a schematic diagram of the application principle of the two-cell lithium battery control chip provided by an embodiment of the present invention.

[0041] Fig.14 It is a schematic diagram of the front structure of a two-cell lithium battery protection board provided in an embodiment of the present invention.

[0042] Fig.15 It is a schematic diagram of the back structure of a two-cell lithium battery protection board provided in an embodiment of the present invention.

[0043] Fig.16 This is an internal block diagram of a three-cell lithium battery control chip provided by an embodiment of the present invention.

[0044] Fig.17 It is a schematic diagram of the application principle of the three-cell lithium battery control chip provided by an embodiment of the present invention.

[0045] Fig.18 It is a schematic diagram of the front structure of a three-cell lithium battery protection board provided in an embodiment of the present invention.

[0046] Fig.19 It is a schematic diagram of the back structure of a three-cell lithium battery protection board provided in an embodiment of the present invention.

[0047] Figure numerals: 1. lithium battery control chip; 11. input module; 12. protection module; 13. output module; 14. anti-reverse module; 2. switch chip; 3. resistance adjustment module; 31. first adjustment unit; 32. second adjustment unit; 4. driving resistor; 5. packaging body. DETAILED DESCRIPTION

[0048] The present invention discloses a lithium battery protection circuit and architecture. In order to make the purpose, technical solution and effect of the present invention clearer and more specific, the present invention is further described in detail with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0049] When lithium batteries are used to supply power to loads, lithium battery protection boards are required to protect the lithium battery from overcurrent and overvoltage during charging. Different loads require different lithium battery models, and the overcurrent capacity of the lithium battery protection board must also correspond to the load and lithium battery. The overcurrent capacity of the lithium battery protection board is related to the chip internal resistance and heat dissipation. Among them, the chip internal resistance is related to the on-resistance of the switch chip, and the package internal resistance is related to the wire resistance and the number of wires. When the on-resistance of the switch chip is small, a larger current value will be allowed to pass. For the traditional cascade method, multiple switch chips (of the same model) are connected in parallel after the lithium battery control chip, which reduces the overall resistance value of the switch module, thereby expanding the current value allowed to pass. The present application adopts a switch chip with a smaller internal resistance to replace the entire switch module, and utilizes the resistance adjustment module additionally configured on the lithium battery control chip to adjust the resistance of the driving resistor additionally configured thereon, and sets the resistance of the driving resistor in direct proportion to the opening and closing time of the switch chip, thereby controlling the switch chip to be at the optimal opening and closing time through the control chip, thereby achieving an increase in the overcurrent value while more accurately controlling the on and off of the switch chip, thereby improving traditional problems.

[0050] like Figure 2 and Figure 4 As shown, the embodiment of the present application discloses a lithium battery protection circuit, which is packaged on a lithium battery protection board and is used to protect the charging and discharging of a lithium battery, and includes:

[0051] A lithium battery control chip 1 and a switch chip 2 which are packaged together and arranged one by one;

[0052] The lithium battery control chip 1 has a resistance adjustment module 3 and a driving resistor 4;

[0053] The resistance adjustment module 3 is respectively connected to the control end of the lithium battery control chip 1 and one end of the driving resistor 4, the other end of the driving resistor 4 is connected to the control end of the switch chip 2, and the other end of the driving resistor 4 serves as the driving end of the lithium battery control chip 1;

[0054] The control end of the lithium battery control chip 1 outputs a control signal to control the conduction timing of the resistance adjustment module 3, and adjusts the resistance of the driving resistor 4. The resistance of the driving resistor 4 is set in direct proportion to the opening time and closing time of the switch chip 2, so that the driving current output by the driving end of the lithium battery control chip 1 is adapted to the opening and closing time of the switch chip 2.

[0055] A lithium battery protection board encapsulated with a lithium battery control chip 1 and a switch chip 2 is used to protect the charging and discharging of the lithium battery. Different loads need to output currents of different gears. At this time, based on the setting of the lithium battery control chip 1, it is only necessary to replace different switch chips 2. Different switch chips 2 correspond to different optimal opening and closing times. The opening and closing time of the switch chip 2 matches the current size of the input switch chip 2. The lithium battery control chip 1 controls the current size input to the control end (gate) of the switch chip 2. In specific implementation, the control signal of the lithium battery control chip 1 is used to control the conduction timing of the built-in resistance adjustment module 3 to adjust the resistance of the driving resistor 4. Specifically, the control signal output by the control end of the lithium battery control chip 1 is a high-level signal or a low-level signal, thereby controlling the current size flowing to the control end (gate) of the switch chip 2 to achieve the optimal opening and closing time of the switch chip and more accurately control the switch chip. Therefore, the present application adopts a solution of combining a lithium battery control chip 1 and a switch chip 2. Different switch chips 2 are selected according to different output current requirements, and the optimal opening and closing times of the switch chips 2 are matched, so there is no need to cascade multiple switch chips 2. This solves the problem of the switch chip 2 being easily damaged due to inconsistent control of the switch chip, improves the service life of the device, and is also beneficial to cost control (reducing the number of chips used and reducing the size of the lithium battery protection board).

[0056] It should be noted that the current expansion method of the existing lithium battery protection board is to achieve it by cascading multiple switch chips of the same model. Therefore, there is no need for the lithium battery control chip to adjust the driving end. However, due to the inconsistent electrical parameters of each switch chip in actual applications (product error), and the different wire lengths caused by the layout of the switch chip, the parasitic resistance and capacitance introduced are inconsistent, which will eventually cause the lithium battery control chip to output the same control signal, and the switch chip cannot be synchronized on and off. In this way, the last switch chip to be turned off carries all the current of the circuit at the moment of turning off, which leads to damage to the switch chip; at the same time, for the requirements of different load overcurrent values, corresponding adaptation is achieved only by adjusting the parallel number of switch chips; however, no matter how the parallel number of switch chips is adjusted, the opening and closing times in the control signal output by the control chip do not change, which further leads to inconsistent opening or closing times of the switch chips, which is more likely to cause damage to the switch chips and cause the lithium battery protection board to fail.

[0057] In the present application, only one control chip and one switch chip are provided, and the control chip and the switch chip are packaged together, thereby effectively reducing the volume; at the same time, by replacing switch chips with different overcurrent values, the needs of different loads are met, and the driving end of the lithium battery control chip is improved, that is, the setting of the resistance adjustment module and the driving resistor is added to realize the control of the optimal opening and closing time of the switch chip, so as to realize the on and off of the switch chip more accurately, so that the control chip in the present application can adapt to switch chips with different overcurrent values, and according to the needs of different switch chips, the optimal opening and closing time corresponding to the switch chip is adaptively adjusted, so that the switch chip is not easily damaged, its service life is increased, and the number of chips used is reduced, which is conducive to cost control and ensures the service life of the lithium battery protection board.

[0058] In the embodiments of the present application, Figure 3 As shown, the lithium battery control chip 1 has an input module 11, a protection module 12 and an output module 13. The input module 11 includes a reference unit and an oscillation unit. The protection module 12 includes a logic function unit, a charge and discharge protection unit, an undervoltage protection unit, an overvoltage protection unit, an overcurrent protection unit, and a short circuit protection unit. The charge and discharge protection unit, the undervoltage protection unit, the overvoltage protection unit, the overcurrent protection unit, and the short circuit protection unit are all connected to the logic function unit. The output module 13 is used to output a control signal to the switch chip 2. The lithium battery control chip has at least five pins, and the at least five pins include a power pin VDD, a ground pin GND, an overcharge control pin OC, an overdischarge control pin OD, and a detection pin CS.

[0059] In the specific implementation, the power supply signal is first processed preliminarily through the input module, and then the battery voltage is detected by the overvoltage protection unit and the undervoltage protection unit to determine whether it is in an overvoltage or undervoltage state, and the detection pin CS of the lithium battery control chip is used to determine whether the chip is in a charging or discharging state, and whether it is an overcharge or over-discharge state. Then the logic function unit controls the overcharge control pin OC and the over-discharge control pin OD according to the above status information, thereby achieving the purpose of changing the driving current of the control end of the switch chip 2, so that the lithium battery can be charged and discharged normally.

[0060] Specifically, the switch chip 2 is a dual MOS chip, and the switch chip 2 includes a first NMOS transistor U2 and a second NMOS transistor U3. Figure 2As shown, it is a connection diagram of the lithium battery control chip 1 and the switch chip 2. The overcharge control pin (OC) of the lithium battery control chip U1 is connected to the gate of the first NMOS tube U2, the source of the first NMOS tube U2 is connected to the detection pin (CS) of the lithium battery control chip U1, the drain of the first NMOS tube U2 is connected to the drain of the second NMOS tube U3, the gate of the second NMOS tube U3 is connected to the over-discharge control pin (OD) of the lithium battery control chip U1, and the source of the second NMOS tube U3 is connected to the ground pin (GND). The driving end of the lithium battery control chip 1 is the overcharge control pin OC and the over-discharge control pin OD, and the control end of the switch chip 2 is the gate of the first NMOS tube U2 and the gate of the second NMOS tube U3.

[0061] In some embodiments, Figure 4 As shown, the resistance adjustment module 3 includes a first adjustment unit 31 and a second adjustment unit 32, the input ends of the first adjustment unit 31 and the second adjustment unit 32 are connected to the lithium battery control chip 1, and the output ends of the first adjustment unit 31 and the second adjustment unit 32 are connected to the driving resistor 4, and the first adjustment unit 31 and the second adjustment unit 32 are used to adjust the resistance of the driving resistor 4 according to the control signal of the lithium battery control chip 1. Specifically, the first adjustment unit 31 and the second adjustment unit 32 adjust the resistance by controlling the number of circuits connected to the driving resistor 4, and the driving resistor 4 includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, and an eighth resistor R8.

[0062] The first regulating unit 31 includes a first AND gate U8-A, a second AND gate U7-A, a third AND gate U6-A, a fourth AND gate U5-A, a first MOS transistor Q1, a second MOS transistor Q2, a third MOS transistor Q3 and a fourth MOS transistor Q4, a first input end of the first AND gate U8-A is connected to the A0 end of the lithium battery control chip, a second input end of the first AND gate U8-A is connected to the AN end of the lithium battery control chip, an output end of the first AND gate U8-A is connected to the gate of the first MOS transistor Q1, a drain of the first MOS transistor Q1 is connected to one end of the first resistor R1, and a source of the first MOS transistor Q1 is grounded;

[0063] The first input end of the second AND gate U7-A is connected to the A1 end of the lithium battery control chip, the second input end of the second AND gate U7-A is connected to the AN end of the lithium battery control chip, the output end of the second AND gate U7-A is connected to the gate of the second MOS tube Q2, the drain of the second MOS tube Q2 is connected to one end of the second resistor R2, and the source of the second MOS tube Q2 is grounded;

[0064] A first input end of the third AND gate U6-A is connected to the A2 end of the lithium battery control chip, a second output end of the third AND gate U6-A is connected to the AN end of the lithium battery control chip, an output end of the third AND gate U6-A is connected to the gate of the third MOS tube Q3, a drain of the third MOS tube Q3 is connected to one end of the third resistor R3, and a source of the third MOS tube Q3 is grounded;

[0065] The first input end of the fourth AND gate U5-A is connected to the A3 end of the lithium battery control chip, the second input end of the fourth AND gate U5-A is connected to the AN end of the lithium battery control chip, the output end of the fourth AND gate U5-A is connected to the gate of the fourth MOS tube Q4, the drain of the fourth MOS tube Q4 is connected to one end of the fourth resistor R4, and the source of the fourth MOS tube Q4 is grounded.

[0066] Specifically, the AN terminal, A0 terminal, A1 terminal, A2 terminal and A3 terminal of the lithium battery control chip are all control terminals of the lithium battery control chip, and the first MOS tube Q1, the second MOS tube Q2, the third MOS tube Q3 and the fourth MOS tube Q4 are all NMOS tubes, which will be turned on when the input signal is high level, that is, only when the control signals of the AN terminal and the A1 terminal are both high level signals, and then after passing through the first AND gate, a high level signal will be output, and the first MOS tube Q1 will be turned on. The AN terminal is the total control terminal, and similarly, the control principle of the second MOS tube Q2, the third MOS tube Q3 and the fourth MOS tube Q4 is the same, so that by controlling the conduction or shutdown of the first MOS tube Q1, the second MOS tube Q2, the third MOS tube Q3 or the fourth MOS tube Q4, the first resistor R1, the second resistor R2, the third resistor R3 or the fourth resistor R4 are controlled to be connected to the circuit, that is, the resistance value of the driving resistor is changed, so as to control the magnitude of the current value input to the switch chip, and finally control the shutdown speed of the switch chip. Compared with general methods, the present application has higher adjustment and control accuracy, thereby adopting the best timing switch, reducing circuit loss, and greatly reducing the damage to the device caused by the current shock during shutdown, thereby improving the safety of use.

[0067] In some embodiments, the second regulating unit 32 includes a first OR gate U16-A, a second OR gate U15-A, a third OR gate U14-A, a fourth OR gate U13-A, a fifth MOS transistor Q5, a sixth MOS transistor Q6, a seventh MOS transistor Q7 and an eighth MOS transistor Q8, the first input end of the first OR gate U16-A, is connected to the B0 end of the lithium battery control chip, the second input end of the first OR gate U16-A, is connected to the BN end of the lithium battery control chip, the output end of the first OR gate U16-A, is connected to the gate of the fifth MOS transistor Q5, the source of the fifth MOS transistor Q5 is grounded, and the drain of the fifth MOS transistor Q5 is connected to one end of the fifth resistor R5;

[0068] A first input end of the second OR gate U15-A is connected to the B1 end of the lithium battery control chip, a second input end of the second OR gate U15-A is connected to the BN end of the lithium battery control chip, an output end of the second OR gate U15-A is connected to the gate of the sixth MOS tube Q6, a source of the sixth MOS tube Q6 is grounded, and a drain of the sixth MOS tube Q6 is connected to one end of the sixth resistor R6;

[0069] A first input end of the third OR gate U14-A is connected to the B2 end of the lithium battery control chip, a second input end of the third OR gate U14-A is connected to the BN end of the lithium battery control chip, an output end of the third OR gate U14-A is connected to the gate of the seventh MOS tube Q7, a source of the seventh MOS tube Q7 is grounded, and a drain of the seventh MOS tube Q7 is connected to one end of the seventh resistor R7;

[0070] The first input end of the fourth OR gate U13-A is connected to the B3 end of the lithium battery control chip, the second input end of the fourth OR gate U13-A is connected to the BN end of the lithium battery control chip, the output end of the fourth OR gate U13-A is connected to the gate of the eighth MOS tube Q8, the source of the eighth MOS tube Q8 is grounded, and the drain of the eighth MOS tube Q8 is connected to one end of the eighth resistor R8.

[0071] In specific implementation, the adjustment process is similar to that of the first adjustment unit, wherein the BN terminal, B0 terminal, B1 terminal, B2 terminal and B3 terminal of the lithium battery control chip are all control terminals of the lithium battery control chip, the fifth MOS tube Q5, the sixth MOS tube Q6, the seventh MOS tube Q7 and the eighth MOS tube Q8 are all PMOS tubes, and when the signal input to the PMOS tube is a low-level signal, the PMOS tube is turned on, that is, only when the control signals output from the BN terminal and the B1 terminal are both low-level signals, a low-level signal will be output after passing through the first OR gate, so that the fifth MOS tube Q5 is turned on, and similarly, the sixth MOS tube Q6, the seventh MOS tube Q7 and the eighth MOS tube Q8 are all PMOS tubes. The conduction principle of the OS transistor Q6, the seventh MOS transistor Q7 and the eighth MOS transistor Q8 is the same. Thus, by controlling the conduction of the fifth MOS transistor Q5, the sixth MOS transistor Q6, the seventh MOS transistor Q7 and the eighth MOS transistor Q8, it is controlled whether the fifth resistor R5, the sixth resistor R6, the seventh resistor R7 and the eighth resistor R8 are connected to the circuit, that is, the resistance value of the driving resistor is changed, thereby changing the current value input to the switch chip. When a different switch chip is replaced, the on-off time of the switch chip can be accurately matched, thereby reducing the current impact on the switch chip when it is turned off, and improving safety.

[0072] In some embodiments, Figure 5As shown, the lithium battery protection circuit is also provided with an anti-reverse module 14, which is connected to the input end of the lithium battery control chip U1, and is used to provide anti-reverse protection for the lithium battery control chip U1. Specifically, the anti-reverse module includes a PMOS tube and an ESD diode, the gate of the PMOS tube is grounded, the drain of the PMOS tube is connected to the positive pole of the power supply, the source of the PMOS tube is connected to the VI N terminal of the lithium battery control chip, and the ESD diode is connected in parallel with the PMOS tube to the VI N terminal of the lithium battery control chip, that is, the first pin of the ESD diode is connected to the source of the PMOS tube and the VIN terminal of the lithium battery control chip, and the second and third pins of the ESD diode are grounded.

[0073] In the specific implementation, the power supply is normally connected to the circuit, the PMOS tube is normally turned on, and the lithium battery control chip is powered through the VI N terminal. If the power supply is reversed, the source and drain of the PMOS tube are negative voltages, and the gate is positive voltage. At this time, the PMOS is not turned on, thereby realizing the anti-reverse protection function. Compared with the previous method of using peripheral devices, the resistor is connected in series at the power supply end of the chip. If reverse connection occurs, the lithium battery control chip will be abnormally turned on. The resistor is used to limit the current and will not damage the lithium battery control chip. It can be seen that the anti-reverse design of the present application can eliminate the peripheral situation and still effectively protect the lithium battery control chip from damage. ESD diodes are used to prevent electrostatic interference.

[0074] In other specific embodiments, a lithium battery protection board encapsulated with a lithium battery control chip 1 and a switch chip 2 is used, wherein the lithium battery control chip 1 and the switch chip 2 are each provided with one and encapsulated together; the lithium battery is protected from charging and discharging; the lithium battery control chip has a resistance adjustment module and a driving resistor; the resistance adjustment module is respectively connected to the control end of the lithium battery control chip and one end of the driving resistor, the other end of the driving resistor is connected to the control end of the switch chip, and the other end of the driving resistor serves as the driving end of the lithium battery control chip; the control end of the lithium battery control chip outputs a control signal to control the conduction timing of the resistance adjustment module, and adjusts the resistance of the driving resistor, and the resistance of the driving resistor is set in direct proportion to the opening time and closing time of the switch chip, so that the driving current output by the driving end of the lithium battery control chip is adapted to the opening and closing time of the switch chip.

[0075] At the same time, if different loads need to output currents of different gears, a switch chip with a maximum gear current can be selected to output currents of different gears according to different load needs through the control chip. The control end of the lithium battery control chip outputs a control signal to control the conduction timing of the resistance adjustment module, and adjusts the resistance of the driving resistor, so that the driving current output by the driving end of the lithium battery control chip is the gear current required by the load, so that the lithium battery protection circuit can adapt to loads with different gear current requirements without replacing the switch chip and the control chip.

[0076] In other specific embodiments, a lithium battery protection board encapsulated with a lithium battery control chip 1 and several different switch chips 2 is used, and the lithium battery control chip 1 and several different switch chips 2 are encapsulated together, and the lithium battery protection board is used to protect the charging and discharging of the lithium battery; the lithium battery control chip has a resistance adjustment module and a driving resistor; the resistance adjustment module is respectively connected to the control end of the lithium battery control chip and one end of the driving resistor, and the other end of the driving resistor is connected to the control ends of several of the switch chips, and the other end of the driving resistor serves as the driving end of the lithium battery control chip; the control end of the lithium battery control chip outputs a control signal to control the conduction timing of the resistance adjustment module and adjust the resistance of the driving resistor, and the resistance of the driving resistor is set in direct proportion to the opening time and closing time of the switch chip, so that the driving current output by the driving end of the lithium battery control chip is adapted to the opening and closing times of multiple different switch chips.

[0077] At the same time, the lithium battery control chip is also provided with a switch switching module, which is electrically connected between the driving resistor and a plurality of different switch chips, and is used to control the driving resistor to be electrically connected to a switch chip corresponding to the gear current according to the responsibility of different gear current requirements; that is, the lithium battery protection circuit in this embodiment can adapt to loads with different gear current requirements, and automatically switch the switch chip adapted thereto according to different responsibilities. At the same time, the lithium battery control chip can also control the conduction timing of the resistance adjustment module through the control terminal output control signal, and adjust the resistance of the driving resistor, so that the driving current output by the driving end of the lithium battery control chip is adapted to the opening and closing time of a plurality of different switch chips. In this way, it is ensured that the switch chip connected according to the load is at the best opening and closing time, and the damage of the switch chip is effectively avoided.

[0078] In some embodiments, a lithium battery protection architecture is also disclosed, including a lithium battery protection board, a package 5 and the lithium battery protection circuit as described above, wherein the lithium battery protection circuit is disposed on the lithium battery protection board through the package 5.

[0079] In the specific implementation, the lithium battery control chip and the switch chip adopt an improved EMOSP5 package, which has a 4mm 2 The substrate and the lead frame that supports 20 wires on a single end can hold different types of MOS chips to meet different current requirements. The package can achieve a maximum constant current value of 9 amperes and a maximum overcurrent value of 18 amperes. The present invention is not limited to the EMSOP5 package form and can use corresponding packages of similar structures such as DFN, SOP8, ESOP8, TO263, etc. according to actual applications, and can achieve the same effect.

[0080] like Figure 6 As shown in FIG. 1 , it is a schematic diagram of the packaging and wiring of the lithium battery control chip and the switch chip using the improved EMOSP5 package. Figure 7-9 As shown in the figure, it is the application principle diagram of a single-cell lithium battery control chip. Figure 10-12 The figure shows the application schematic diagram of the lithium battery control chip in a minimalist peripheral environment.

[0081] In some embodiments, the lithium battery control chip can be cascaded with at least one lithium battery, including two lithium batteries or three lithium batteries, and only a battery input and detection and judgment module need to be added inside the chip. Figure 13-15 As shown in the figure, it is the application principle diagram of two lithium batteries. Figure 16-19 As shown, this is the application principle diagram of three lithium batteries. The lithium batteries are connected in parallel at the power supply end of the lithium battery control chip. The operation is simple and easy to implement.

[0082] Compared with the prior art, the present invention has the following advantages:

[0083] 1. This application controls the conduction timing of the resistance adjustment module 3 by outputting a control signal through the lithium battery control chip 1, thereby adjusting the resistance of the driving resistor 4, thereby controlling the current flowing to the switch chip 2, so as to achieve the optimal opening and closing time of the switch chip, and more accurately control the switch chip. Therefore, this application adopts a solution of combining the lithium battery control chip 1 and the switch chip 2, selects different switch chips 2 according to different output current requirements, and matches the optimal opening and closing time of the switch chip 2, so that there is no need to cascade multiple switch chips 2, which solves the problem of the switch chip 2 being easily damaged due to inconsistent control of the switch chip, improves the service life of the switch chip 2 and the lithium battery protection board, and is also conducive to cost control (reducing the number of devices used and reducing the size of the lithium battery protection board).

[0084] It should be understood that the application of the present invention is not limited to the above examples. For ordinary technicians in this field, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A lithium battery protection circuit, packaged on a lithium battery protection board, used to protect the charging and discharging of a lithium battery, characterized in that: include: The lithium battery control chip and the switch chip are packaged together and arranged one by one; The lithium battery control chip has a resistance adjustment module and a driving resistor; The resistance adjustment module is respectively connected to the control end of the lithium battery control chip and one end of the driving resistor, the other end of the driving resistor is connected to the control end of the switch chip, and the other end of the driving resistor serves as the driving end of the lithium battery control chip; The control end of the lithium battery control chip outputs a control signal to control the conduction timing of the resistance adjustment module, and adjusts the resistance of the driving resistor. The resistance of the driving resistor is set in direct proportion to the opening time and closing time of the switch chip, so that the driving current output by the driving end of the lithium battery control chip is adapted to the opening and closing time of the switch chip; The resistance value adjustment module includes a first adjustment unit and a second adjustment unit, wherein the input ends of the first adjustment unit and the second adjustment unit are connected to the control end of the lithium battery control chip, the output ends of the first adjustment unit and the second adjustment unit are connected to the driving resistor, and the first adjustment unit and the second adjustment unit are used to adjust the resistance of the driving resistor according to the control signal of the lithium battery control chip; The first regulating unit and the second regulating unit adjust the resistance value by controlling the number of driving resistors connected to the circuit; the first regulating unit is used to control the magnitude of the current value input to the switch chip, and the second regulating unit changes the current value input to the switch chip. The first regulating unit and the second regulating unit are respectively used to adjust the opening and closing time corresponding to the switch chip.

2. The lithium battery protection circuit according to claim 1, characterized in that: The first regulating unit includes a first AND gate, a second AND gate, a third AND gate, a fourth AND gate, a first MOS transistor, a second MOS transistor, a third MOS transistor and a fourth MOS transistor, the first input end of the first AND gate is connected to the A0 end of the lithium battery control chip, the second input end of the first AND gate is connected to the AN end of the lithium battery control chip, the output end of the first AND gate is connected to the gate of the first MOS transistor, the drain of the first MOS transistor is connected to one end of the driving resistor, and the source of the first MOS transistor is grounded; The first input end of the second AND gate is connected to the A1 end of the lithium battery control chip, the second input end of the second AND gate is connected to the AN end of the lithium battery control chip, the output end of the second AND gate is connected to the gate of the second MOS tube, the drain of the second MOS tube is connected to one end of the driving resistor, and the source of the second MOS tube is grounded; The first input end of the third AND gate is connected to the A2 end of the lithium battery control chip, the second output end of the third AND gate is connected to the AN end of the lithium battery control chip, the output end of the third AND gate is connected to the gate of the third MOS tube, the drain of the third MOS tube is connected to one end of the driving resistor, and the source of the third MOS tube is grounded; The first input end of the fourth AND gate is connected to the A3 end of the lithium battery control chip, the second input end of the fourth AND gate is connected to the AN end of the lithium battery control chip, the output end of the fourth AND gate is connected to the gate of the fourth MOS tube, the drain of the fourth MOS tube is connected to one end of the driving resistor, and the source of the fourth MOS tube is grounded.

3. The lithium battery protection circuit according to claim 2, characterized in that: The second regulating unit includes a first OR gate, a second OR gate, a third OR gate, a fourth OR gate, a fifth MOS tube, a sixth MOS tube, a seventh MOS tube and an eighth MOS tube, wherein the first input end of the first OR gate is connected to the B0 end of the lithium battery control chip, the second input end of the first OR gate is connected to the BN end of the lithium battery control chip, the output end of the first OR gate is connected to the gate of the fifth MOS tube, the source of the fifth MOS tube is grounded, and the drain of the fifth MOS tube is connected to the driving resistor; The first input end of the second OR gate is connected to the B1 end of the lithium battery control chip, the second input end of the second OR gate is connected to the BN end of the lithium battery control chip, the output end of the second OR gate is connected to the gate of the sixth MOS tube, the source of the sixth MOS tube is grounded, and the drain of the sixth MOS tube is connected to the driving resistor; The first input end of the third OR gate is connected to the B2 end of the lithium battery control chip, the second input end of the third OR gate is connected to the BN end of the lithium battery control chip, the output end of the third OR gate is connected to the gate of the seventh MOS tube, the source of the seventh MOS tube is grounded, and the drain of the seventh MOS tube is connected to the driving resistor; The first input end of the fourth OR gate is connected to the B3 end of the lithium battery control chip, the second input end of the fourth OR gate is connected to the BN end of the lithium battery control chip, the output end of the fourth OR gate is connected to the gate of the eighth MOS tube, the source of the eighth MOS tube is grounded, and the drain of the eighth MOS tube is connected to the driving resistor.

4. The lithium battery protection circuit according to claim 1, characterized in that: It also includes an anti-reverse module, which is connected to the input end of the lithium battery control chip. The anti-reverse module includes a PMOS tube and an ESD diode. The gate of the PMOS tube is grounded, the drain of the PMOS tube is connected to the positive pole of the power supply, the source of the PMOS tube is connected to the VIN end of the lithium battery control chip, and the ESD diode is connected in parallel with the PMOS tube to the VIN end of the lithium battery control chip.

5. The lithium battery protection circuit according to claim 1, characterized in that: The lithium battery control chip has at least five pins, and the at least five pins include a power pin, a ground pin, an overcharge control pin, an overdischarge control pin and a detection pin.

6. The lithium battery protection circuit according to claim 5, characterized in that: The switch chip includes a first NMOS tube and a second NMOS tube, the gate of the first NMOS tube is connected to the overcharge pin of the lithium battery control chip, the source of the first NMOS tube is connected to the detection pin of the lithium battery control chip, the drain of the first NMOS tube is connected to the drain of the second NMOS tube, the gate of the second NMOS tube is connected to the over-discharge control pin of the lithium battery control chip, and the source of the second NMOS tube is connected to the ground pin.

7. The lithium battery protection circuit according to claim 1, characterized in that: The lithium battery control chip also has an input module, a protection module and an output module. The input module includes a reference unit and an oscillation unit. The protection module includes a logic function unit, a charge and discharge protection unit, an undervoltage protection unit, an overvoltage protection unit, an overcurrent protection unit, and a short circuit protection unit. The charge and discharge protection unit, the undervoltage protection unit, the overvoltage protection unit, the overcurrent protection unit, and the short circuit protection unit are all connected to the logic function unit. The output module is used to output a control signal to the control end of the switch chip.

8. The lithium battery protection circuit according to claim 1, characterized in that: The lithium battery control chip can be cascaded with at least one lithium battery.

9. A lithium battery protection architecture, characterized in that: It comprises a lithium battery protection board, a packaging body and a lithium battery protection circuit as described in any one of claims 1 to 8, wherein the lithium battery protection circuit is packaged on the lithium battery protection board through the packaging body.

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