Charging and discharging protection circuit and analog power chip

Abstract

The invention discloses a charging and discharging protection circuit and a power simulation chip. The charging and discharging protection circuit comprises a control circuit, a first switch module, a second switch module and a protection module, the power supply end of the control circuit is connected with the first power supply end, the first end of the first switch module is connected with the cathode of the battery, the second end of the first switch module is connected with the second power supply end, and the control circuit is used for controlling on or off of the first switch module according to voltage at two ends of the battery; the grounding end of the control circuit is connected with the first end of the second switch module, the second end of the second switch module is connected with the first end of the first switch module, and the third end of the second switch module is connected with the second end of the first switch module; the protection module is connected with the control circuit in parallel, and the breakdown voltage of the protection module is smaller than that of the control circuit and used for protecting the control circuit when the charging voltage at the two ends of the battery is too large. The reliability of the analog power chip can be improved, and the working stability, safety and reliability of the battery can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of battery protection, and in particular to a charge and discharge protection circuit and an analog power chip. Background Art

[0002] At present, batteries have been used in consumer electronics, communications and IT technology, and their application frequency in industrial applications is increasing. Therefore, during the use of batteries, they must be charged and discharged. In order to prevent the battery from being damaged by abnormal charging and discharging during the charging and discharging process, a battery protection circuit needs to be added to protect the battery. Traditional battery protection circuits usually detect the battery voltage through a control circuit, and control the conduction state of the switch tube according to the battery voltage to control the charging and discharging state of the battery.

[0003] However, with the advancement of technology, some new chargers support higher voltages to support fast charging technology. When high voltage output is directly applied to both ends of the battery, it will cause the battery analog power chip to fail, and more seriously, it will cause the battery to catch fire, making the reliability of the analog power chip poor, thereby reducing the working stability and safety reliability of the battery. Summary of the invention

[0004] The present invention provides a charge and discharge protection circuit and an analog power chip to improve the reliability of the analog power chip and improve the working stability and safety reliability of the battery.

[0005] According to one aspect of the present invention, there is provided a charge and discharge protection circuit, comprising: a control circuit, a first switch module, a second switch module and a protection module;

[0006] The power supply end of the control circuit is connected to the first power supply end, the first end of the first switch module is connected to the negative electrode of the battery, the positive electrode of the battery is connected to the first power supply end, and the second end of the first switch module is connected to the second power supply end. The control circuit is used to control the on or off of the first switch module according to the voltages at both ends of the battery; the ground end of the control circuit is connected to the first end of the second switch module, the second end of the second switch module is connected to the first end of the first switch module, and the third end of the second switch module is connected to the second end of the first switch module. The control circuit is also used to collect a first voltage at the first end of the first switch module and a second voltage at the second end of the first switch module, and output the smaller value of the first voltage and the second voltage to the ground end of the control circuit;

[0007] The protection module is connected in parallel with the control circuit, and the breakdown voltage of the protection module is lower than the breakdown voltage of the control circuit; the protection module is used to protect the control circuit when the charging voltage at both ends of the battery is too large;

[0008] Wherein, the first power supply terminal and the second power supply terminal are used to connect to a charger or a load.

[0009] Optionally, the charge and discharge protection circuit includes a first filter resistor;

[0010] The power supply end of the control circuit is connected to the first power supply end through the first filter resistor;

[0011] The second switch module includes a first switch unit and a second switch unit;

[0012] The first end of the first switch unit is connected to the first end of the second switch unit, the first end of the second switch unit is connected to the ground end of the control circuit, the second end of the first switch unit is connected to the first end of the first switch module, and the second end of the second switch unit is connected to the second end of the first switch module;

[0013] The protection module includes a first protection unit and a first current limiting unit;

[0014] The first end of the first protection unit is connected to the first end of the first filter resistor, the second end of the first protection unit is connected to the first end of the first current limiting unit, the second end of the first current limiting unit is connected to the first end of the second switch unit, and the first end of the first current limiting unit is connected to the ground end of the control circuit.

[0015] Optionally, the first protection unit includes a first diode, and the first current limiting unit includes a first resistor;

[0016] The first electrode of the first diode is connected to the first end of the first filter resistor, the second electrode of the first diode is connected to the first end of the first resistor, the second end of the first resistor is connected to the first end of the second switch unit, and the first end of the first resistor is connected to the ground end of the control circuit.

[0017] Optionally, the first protection unit includes at least two first Zener diodes, and the first current limiting unit includes a second resistor; at least two of the first Zener diodes are connected in series;

[0018] The first ends of at least two of the first Zener diode series circuits are connected to the first end of the first filter resistor, the second ends of at least two of the first Zener diode series circuits are connected to the first end of the second resistor, the second end of the second resistor is connected to the first end of the second switch unit, and the first end of the second resistor is connected to the ground end of the control circuit.

[0019] Optionally, the first protection unit includes a third resistor, a fourth resistor and a first transconductance amplifier, and the first current limiting unit includes a fifth resistor;

[0020] A power supply terminal of the first transconductance amplifier is connected to a first end of the first filter resistor, a first input terminal of the first transconductance amplifier is connected to a first end of the third resistor, a second input terminal of the first transconductance amplifier is connected to a reference power supply terminal, an output terminal of the first transconductance amplifier is connected to a first end of the fifth resistor, a second end of the fifth resistor is connected to a first end of the second switch unit, a first end of the fifth resistor is connected to a ground terminal of the control circuit, a first end of the third resistor is connected to a first end of the fourth resistor, a second end of the fourth resistor is connected to the output terminal of the first transconductance amplifier, and a second end of the third resistor is connected to a first end of the first filter resistor.

[0021] Optionally, the charge and discharge protection circuit includes a second filter resistor;

[0022] The power supply end of the control circuit is connected to the first power supply end through the second filter resistor;

[0023] The second switch module includes a third switch unit and a fourth switch unit;

[0024] The first end of the third switch unit is connected to the first end of the fourth switch unit, the first end of the fourth switch unit is connected to the ground end of the control circuit, the second end of the third switch unit is connected to the first end of the first switch module, and the second end of the fourth switch unit is connected to the second end of the first switch module;

[0025] The protection module includes a second protection unit and a second current limiting unit; the control circuit also includes an output terminal;

[0026] The first end of the second protection unit is connected to the first end of the second filter resistor, the second end of the second protection unit is connected to the first end of the second current limiting unit, the second end of the second current limiting unit is connected to the output end of the control circuit, and the first end of the second current limiting unit is connected to the control end of the first switch module.

[0027] Optionally, the second protection unit includes a second diode, and the second current limiting unit includes a sixth resistor;

[0028] The first electrode of the second diode is connected to the first end of the second filter resistor, the second electrode of the second diode is connected to the first end of the sixth resistor, the second end of the sixth resistor is connected to the output end of the control circuit, and the first end of the sixth resistor is connected to the control end of the first switch module.

[0029] Optionally, the second protection unit includes at least two second Zener diodes, and the second current limiting unit includes a seventh resistor; at least two of the second Zener diodes are connected in series;

[0030] The first ends of at least two of the second Zener diode series circuits are connected to the first ends of the second filter resistor, the second ends of at least two of the second Zener diode series circuits are connected to the first end of the seventh resistor, the second end of the seventh resistor is connected to the output end of the control circuit, and the first end of the seventh resistor is connected to the control end of the first switch module.

[0031] Optionally, the second protection unit includes an eighth resistor, a ninth resistor and a second transconductance amplifier, and the second current limiting unit includes a tenth resistor;

[0032] The power supply terminal of the second transconductance amplifier is connected to the first end of the second filter resistor, the first input terminal of the second transconductance amplifier is connected to the first end of the eighth resistor, the second input terminal of the second transconductance amplifier is connected to the reference power supply terminal, the output terminal of the second transconductance amplifier is connected to the first end of the tenth resistor, the second end of the tenth resistor is connected to the output terminal of the control circuit, the first end of the tenth resistor is connected to the control terminal of the first switch module, the first end of the eighth resistor is connected to the first end of the ninth resistor, the second end of the ninth resistor is connected to the output terminal of the second transconductance amplifier, and the second end of the eighth resistor is connected to the first end of the second filter resistor.

[0033] Optionally, the charge and discharge protection circuit further includes a power supply voltage generating circuit;

[0034] The power supply end of the control circuit is connected to the first power supply end through the power supply voltage generating circuit, and the power supply voltage generating circuit is used to provide power to the control circuit.

[0035] Optionally, the power supply voltage generating circuit includes a fifth switch unit, a sixth switch unit, a current control unit and an eleventh resistor;

[0036] The first end of the current control unit is connected to the first power supply end, the second end of the current control unit is connected to the first end of the eleventh resistor, the first end of the eleventh resistor is connected to the control end of the fifth switch unit, the first end of the fifth switch unit is connected to the first power supply end, the second end of the fifth switch unit is connected to the power supply end of the control circuit, the second end of the eleventh resistor is connected to the first end of the sixth switch unit, the control end of the sixth switch unit is connected to the negative electrode of the battery, and the second end of the sixth switch unit is connected to the ground end of the control circuit.

[0037] Optionally, the fifth switch unit includes a first transistor, and the sixth switch unit includes a second transistor;

[0038] The control electrode of the first transistor is connected to the second end of the current control unit, the first electrode of the first transistor is connected to the first power supply end, the second electrode of the first transistor is connected to the power supply end of the control circuit, the control electrode of the second transistor is connected to the negative electrode of the battery, the first electrode of the second transistor is connected to the second end of the eleventh resistor, and the second electrode of the second transistor is connected to the ground end of the control circuit.

[0039] Optionally, the current control unit includes a current mirror;

[0040] A first end of the current mirror is connected to the first power supply end, and a second end of the current mirror is connected to the control end of the fifth switch unit and to the first end of the eleventh resistor.

[0041] Optionally, the first switch module includes a third transistor; the control circuit further includes an output terminal;

[0042] The control electrode of the third transistor is connected to the output end of the control circuit, the first electrode of the third transistor is connected to the negative electrode of the battery, and the second electrode of the third transistor is connected to the second power supply end.

[0043] According to another aspect of the present invention, an analog power chip is provided, comprising the charge and discharge protection circuit provided by any of the above embodiments.

[0044] The technical solution of the embodiment of the present invention controls the output voltage of the second switch module according to the difference between the first power supply terminal and the second power supply terminal connected to the charger or the load, thereby controlling the voltage of the ground terminal of the control circuit. The control circuit detects the voltage of the battery during the charging process and the discharging process, and controls the conduction state of the first switch module according to the detected voltage, thereby controlling the charging circuit and the discharging circuit of the battery. The charging path can be cut off when the voltage at both ends of the battery is too high, and the discharging path can be cut off when the battery is over-discharged, thereby protecting the battery and extending the service life of the battery. By setting the breakdown voltage of the protection module to be less than the breakdown voltage of the control circuit, the control circuit is protected when the charging voltage at both ends of the battery is too large. When the charging voltage at both ends of the battery is too large and reaches the breakdown voltage of the protection module, the excessive voltage can be prevented from continuing to be transmitted to the control circuit, and the control circuit is prevented from being damaged by breakdown due to the excessive voltage, which greatly extends the service life of the control circuit, thereby improving the reliability of the analog power chip, and improving the working stability and safety reliability of the battery.

[0045] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0047] Figure 1 A schematic diagram of the structure of a charge and discharge protection circuit provided according to an embodiment of the present invention;

[0048] Figure 2 A schematic diagram of the structure of another charge and discharge protection circuit provided according to an embodiment of the present invention;

[0049] Figure 3 A schematic diagram of the structure of another charge and discharge protection circuit provided according to an embodiment of the present invention;

[0050] Figure 4 A schematic diagram of the structure of another charge and discharge protection circuit provided according to an embodiment of the present invention;

[0051] Figure 5 A schematic diagram of the structure of another charge and discharge protection circuit provided according to an embodiment of the present invention;

[0052] Figure 6 A schematic diagram of the structure of another charge and discharge protection circuit provided according to an embodiment of the present invention;

[0053] Figure 7 A schematic diagram of the structure of another charge and discharge protection circuit provided according to an embodiment of the present invention;

[0054] Figure 8 A schematic diagram of the structure of another charge and discharge protection circuit provided according to an embodiment of the present invention;

[0055] Fig. 9 A schematic diagram of the structure of another charge and discharge protection circuit provided according to an embodiment of the present invention;

[0056] Fig.10 A schematic diagram of the structure of another charge and discharge protection circuit provided according to an embodiment of the present invention;

[0057] Fig.11 A schematic diagram of the structure of another charge and discharge protection circuit provided according to an embodiment of the present invention;

[0058] Fig.12 A schematic diagram of the structure of another charge and discharge protection circuit provided according to an embodiment of the present invention;

[0059] Fig.13A schematic diagram of the structure of another charge and discharge protection circuit provided according to an embodiment of the present invention;

[0060] Fig.14 A schematic diagram of the structure of another charge and discharge protection circuit provided according to an embodiment of the present invention;

[0061] Fig.15 A schematic diagram of the structure of another charge and discharge protection circuit provided according to an embodiment of the present invention;

[0062] Fig.16 A schematic diagram of the structure of another charge and discharge protection circuit provided according to an embodiment of the present invention;

[0063] Fig.17 A schematic diagram of the structure of a power supply voltage generating circuit provided according to an embodiment of the present invention;

[0064] Fig.18 It is a schematic diagram of the structure of another power supply voltage generating circuit provided according to an embodiment of the present invention. DETAILED DESCRIPTION

[0065] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme 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 part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0066] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0067] Figure 1 FIG. 1 is a schematic diagram of a charge and discharge protection circuit according to an embodiment of the present invention. Figure 1The charge and discharge protection circuit includes: a control circuit 10, a first switch module 20, a second switch module 30 and a protection module 40; the power supply end of the control circuit 10 is connected to the first power supply end P+, the first end of the first switch module 20 is connected to the negative electrode of the battery BAT, the positive electrode of the battery BAT is connected to the first power supply end P+, the second end of the first switch module 20 is connected to the second power supply end P-, and the control circuit 10 is used to control the conduction or shutdown of the first switch module 20 according to the voltage across the battery BAT; the ground end of the control circuit 10 is connected to the first end of the second switch module 30, and the second end of the second switch module 30 is connected to the first switch module 20 The first end of the second switch module 30 is connected to the second end of the first switch module 20, and the third end of the second switch module 30 is connected to the second end of the first switch module 20. The control circuit 10 is also used to collect the first voltage of the first end of the first switch module 20 and the second voltage of the second end of the first switch module 20, and output the smaller value of the first voltage and the second voltage to the ground terminal of the control circuit 10; the protection module 40 is connected in parallel with the control circuit 10, and the breakdown voltage of the protection module 40 is less than the breakdown voltage of the control circuit 10; the protection module 40 is used to protect the control circuit 10 when the charging voltage at both ends of the battery is too large; wherein, the first power supply terminal P+ and the second power supply terminal P- are used to connect a charger or a load.

[0068] Among them, the battery BAT may include a lithium battery, and the charge and discharge protection circuit may be integrated into a power simulation chip.

[0069] Optionally, the negative electrode of the battery BAT is grounded.

[0070] The control circuit 10 is used to control the conduction state of the second switch module 30 according to whether the first power terminal P+ and the second power terminal P− are connected to a charger or a load, thereby controlling the voltage VB at the first end of the second switch module 30 .

[0071] The control circuit 10 is also used to detect the voltage across the battery BAT during the charging and discharging process of the battery BAT, and control the voltage at the control end of the first switch module 20 according to the voltage across the battery BAT, so as to control the conduction state of the first switch module 20, thereby controlling the charging process between the charger and the battery BAT and the discharging process between the battery BAT and the load. Exemplarily, the control circuit 10 transmits the voltage at the power supply end of the control circuit 10 to the control end of the first switch module 20 according to the voltage across the battery BAT, or transmits the voltage at the ground end of the control circuit 10 to the control end of the first switch module 20.

[0072] Specifically, during the discharge process of the battery BAT, the control circuit 10 transmits the voltage of its power supply end to the control end of the first switch module 20, the first switch module 20 is in the on state, and the battery BAT normally supplies power to the load. When the control circuit 10 detects that the voltage at both ends of the battery BAT is lower than the preset voltage, since the first power supply end P+ and the second power supply end P- are connected to the load at this time, the first voltage at the first end of the first switch module 20 is the ground voltage (0V), and the second voltage at the second end of the first switch module 20 may be the ground voltage or a positive voltage. Then the control circuit 10 transmits the first voltage of the first end of the first switch module 20 to the ground end of the control circuit 10, and the control circuit 10 transmits the voltage of the ground end to the control end of the first switch module 20, so that the first switch module 20 is in the off state, thereby cutting off the discharge circuit between the battery BAT and the load.

[0073] During the charging process of the battery BAT, the control circuit 10 transmits the voltage of its power supply end to the control end of the first switch module 20, the first switch module 20 is in the on state, and the charger normally charges the battery BAT. When the control circuit 10 detects that the voltage at both ends of the battery BAT is higher than its threshold voltage, since the first power supply end P+ and the second power supply end P- are connected to the charger at this time, the first voltage at the first end of the first switch module 20 is the ground voltage (0V), and the second voltage at the second end of the first switch module 20 is a negative voltage. Then the control circuit 10 transmits the second voltage at the second end of the first switch module 20 to the ground end of the control circuit 10, and the control circuit 10 transmits the voltage at the ground end to the control end of the first switch module 20, so that the first switch module 20 is in the off state, thereby cutting off the charging circuit between the battery BAT and the charger. However, during the charging process of the battery BAT, when the larger voltage at both ends of the charger is directly connected to the voltage BAT, for example, greater than the breakdown voltage of the control circuit 10, at this time, the control circuit 10 will fail and cannot protect the battery BAT, so that the working stability and safety reliability of the battery BAT are reduced. Therefore, the control circuit 10 needs to be protected to improve the reliability of the control circuit 10. Therefore, the following embodiments will specifically describe the working principle of the protection module 40 protecting the control circuit 10.

[0074] Specifically, since the breakdown voltage of the protection module 40 is lower than the breakdown voltage of the control circuit 10, the protection module 40 will be broken down when the charging voltage at both ends of the battery BAT is large. At this time, there is a large current between the first power supply terminal P+ and the second power supply terminal P-, and the control circuit 10 controls the first switch module 20 to be in the on state, and the current between the first power supply terminal P+ and the second power supply terminal P- is discharged through the path from the protection module 40 to the second switch module 30 to the first switch module 20 to the ground. When the discharge current is greater than the maximum current of the charger, the voltage between the first power supply terminal P+ and the second power supply terminal P- will be clamped at the breakdown voltage of the protection module 40, thereby protecting the control circuit 10.

[0075] The technical solution of the embodiment of the present invention controls the output voltage of the second switch module according to the difference between the first power supply terminal and the second power supply terminal connected to the charger or the load, thereby controlling the voltage of the ground terminal of the control circuit. The control circuit detects the voltage of the battery during the charging process and the discharging process, and controls the conduction state of the first switch module according to the detected voltage, thereby controlling the charging circuit and the discharging circuit of the battery. The charging path can be cut off when the voltage at both ends of the battery is too high, and the discharging path can be cut off when the battery is over-discharged, thereby protecting the battery and extending the service life of the battery. By setting the breakdown voltage of the protection module to be less than the breakdown voltage of the control circuit, the control circuit is protected when the charging voltage at both ends of the battery is too large. When the charging voltage at both ends of the battery is too large and reaches the breakdown voltage of the protection module, the excessive voltage can be prevented from continuing to be transmitted to the control circuit, and the control circuit is prevented from being damaged by breakdown due to the excessive voltage, which greatly extends the service life of the control circuit, thereby improving the reliability of the analog power chip, and improving the working stability and safety reliability of the battery.

[0076] Figure 2 FIG. 1 is a schematic diagram of another charge and discharge protection circuit according to an embodiment of the present invention. Figure 2 Based on the above embodiment, optionally, the charge and discharge protection circuit includes a first filter resistor R S1 ; The power supply end of the control circuit 10 passes through the first filter resistor R S1 Connect to the first power terminal P+.

[0077] The second switch module 30 includes a first switch unit 31 and a second switch unit 32; the first end of the first switch unit 31 is connected to the first end of the second switch unit 32, the first end of the second switch unit 32 is connected to the ground end of the control circuit 10, the second end of the first switch unit 31 is connected to the first end of the first switch module 20, and the second end of the second switch unit 32 is connected to the second end of the first switch module 20.

[0078] Among them, the first switch unit 31 is used to transmit the first voltage at the first end of the first switch module 20 to the ground end of the control module 10 when it is turned on; the second switch unit 32 is used to transmit the second voltage at the second end of the first switch module 20 to the ground end of the control module 10 when it is turned on.

[0079] The protection module 40 includes a first protection unit 41 and a first current limiting unit 42; the first end of the first protection unit 41 is connected to the first filter resistor R S1 The first end of the first protection unit 41 is connected to the first end of the first current limiting unit 42, the second end of the first current limiting unit 42 is connected to the first end of the second switch unit 32, and the first end of the first current limiting unit 42 is connected to the ground end of the control circuit 10.

[0080] The breakdown voltage of the first protection unit 41 is smaller than the breakdown voltage of the control circuit 10, and is used to be broken down when the charging voltage across the battery BAT is large, so as to protect the control circuit 10. The first current limiting unit 42 is used to limit the current when the first protection unit 41 is broken down.

[0081] Figure 3 FIG. 1 is a schematic diagram of another charge and discharge protection circuit according to an embodiment of the present invention. Figure 3 On the basis of the above embodiments, optionally, the first protection unit 41 includes a first diode D1, and the first current limiting unit 42 includes a first resistor R1; the first electrode of the first diode D1 is connected to the first filter resistor R S1 The first end of the first diode D1 is connected to the first end of the first resistor R1, the second end of the first resistor R1 is connected to the first end of the second switch unit 32, and the first end of the first resistor R1 is connected to the ground end of the control circuit 10.

[0082] The first diode D1 may be any PN junction formed by a process.

[0083] Combination Figure 2 and Figure 3 Specifically, since the breakdown voltage of the first diode D1 is lower than the breakdown voltage of the control circuit 10, the first diode D1 will be broken down when the charging voltage at both ends of the battery BAT is large. After the first diode D1 is broken down, the large current between the first power supply terminal P+ and the second power supply terminal P- will form a voltage drop at the first resistor R1. At this time, the voltage at the ground terminal of the control circuit 10 is greater than 0V, so that the voltage at the control terminal of the first switch module 20 is greater than 0V. At this time, the first switch module 20 cannot be completely turned off, and then, there is a large current between the charger and the ground, and the current flows from the first power supply terminal P+ to the first filter resistor R S1The discharge current is discharged through the path from the first diode D1 to the first resistor R1 to the second switch unit 32 to the first switch module 20 to the ground. When the discharge current is greater than the maximum current of the charger, the voltage between the first power supply terminal P+ and the second power supply terminal P- will be clamped at the breakdown voltage of the protection module 40, thereby protecting the control circuit 10.

[0084] Figure 4 FIG. 1 is a schematic diagram of another charge and discharge protection circuit according to an embodiment of the present invention. Figure 4 On the basis of the above embodiments, optionally, the first switch module 20 includes a third transistor NM0; the first switch unit 31 includes a first switch S1, and the second switch unit 32 includes a second switch S2. The control end of the third transistor NM0 is connected to the control circuit 10, the first electrode of the third transistor NM0 is connected to the negative electrode of the battery BAT and connected to the second end of the first switch S1, the second electrode of the third transistor NM0 is connected to the second power supply terminal P- and connected to the second end of the second switch S2, the first end of the first switch S1 is connected to the first end of the second switch S2, and the first end of the second switch S2 is connected to the second end of the first resistor R1.

[0085] When a charger is connected between the first power supply terminal P+ and the second power supply terminal P-, the first voltage of the first electrode of the third transistor NM0 is the ground voltage, and the second voltage of the second electrode of the third transistor NM0 is a negative voltage. At this time, the control circuit 10 can control the second switch S2 to be closed, so that the second voltage of the second electrode of the third transistor NM0 is transmitted to the second end of the first resistor R1.

[0086] When a load is connected between the first power supply terminal P+ and the second power supply terminal P-, the first voltage of the first electrode of the third transistor NM0 is the ground voltage (0V), and the second voltage of the second electrode of the third transistor NM0 may be the ground voltage (0V) or a positive voltage. At this time, the control circuit 10 can control the first switch S1 to be closed, so that the first voltage of the first electrode of the third transistor NM0 is transmitted to the second end of the first resistor R1.

[0087] Combination Figures 2 to 4 Specifically, since the breakdown voltage of the first diode D1 is lower than the breakdown voltage of the control circuit 10, the first diode D1 will be broken down when the charging voltage at both ends of the battery BAT is large. After the first diode D1 is broken down, the large current between the first power supply terminal P+ and the second power supply terminal P- will form a voltage drop at the first resistor R1. At this time, the voltage at the ground terminal of the control circuit 10 is greater than 0V, so that the voltage at the control terminal of the third transistor NM0 is greater than 0V. At this time, the third transistor NM0 cannot be completely turned off, and then there is a large current between the charger and the ground, and the current flows from the first power supply terminal P+ to the first filter resistor R S1The discharge current is discharged through the path from the first diode D1 to the first resistor R1 to the second switch S2 to the third transistor NM0 to the ground. When the discharge current is greater than the maximum current of the charger, the voltage between the first power supply terminal P+ and the second power supply terminal P- will be clamped at the breakdown voltage of the protection module 40, thereby protecting the control circuit 10.

[0088] Figure 5 FIG. 1 is a schematic diagram of another charge and discharge protection circuit according to an embodiment of the present invention. Figure 5 On the basis of the above embodiments, optionally, the first protection unit 41 includes at least two first Zener diodes, the first current limiting unit 42 includes a second resistor R2; at least two first Zener diodes are connected in series; the first end of the at least two first Zener diode series circuit is connected to the first filter resistor R S1 The first end of the at least two first Zener diode series circuits is connected to the first end of the second resistor R2, the second end of the second resistor R2 is connected to the first end of the second switch unit 32, and the first end of the second resistor R2 is connected to the ground end of the control circuit 10. Among them, the at least two first Zener diode series circuits are used to be broken down when the charging voltage at both ends of the battery BAT is large to protect the control circuit 10. The number of the first Zener diodes Z1 is determined by the highest withstand voltage of the control circuit 10. Figure 5 exemplarily shows that the at least two first Zener diodes include two first Zener diodes Z1.

[0089] For example, when the breakdown voltage of the control circuit 10 is 16V, if the breakdown voltage of the first Zener diode Z1 is 6.8V, two first Zener diodes Z1 are needed to protect the control circuit 10. The protection principle of the control circuit 10 by the at least two first Zener diodes in series circuit and the second resistor R2 is similar, and will not be described in detail here.

[0090] Figure 6 FIG. 1 is a schematic diagram of another charge and discharge protection circuit according to an embodiment of the present invention. Figure 6 On the basis of the above embodiments, optionally, the first switch module includes a third transistor NM0; the first switch unit 31 includes a first switch S1, and the second switch unit 32 includes a second switch S2. The control end of the third transistor NM0 is connected to the control circuit 10, the first electrode of the third transistor NM0 is connected to the negative electrode of the battery BAT and connected to the second end of the first switch S1, the second electrode of the third transistor NM0 is connected to the second power supply terminal P- and connected to the second end of the second switch S2, the first end of the first switch S1 is connected to the first end of the second switch S2, and the first end of the second switch S2 is connected to the second end of the second resistor R2.

[0091] Combination Figure 5 and Figure 6Specifically, when at least two first Zener diode series circuits are broken down, a large current between the charger and the ground flows along the first power supply terminal P+ to the first filter resistor R S1 The current is discharged through a path from the first Zener diode Z1 to the second resistor R2 to the second switch S2 to the third transistor NM0 to the ground.

[0092] Figure 7 FIG. 1 is a schematic diagram of another charge and discharge protection circuit according to an embodiment of the present invention. Figure 7 On the basis of the above embodiments, optionally, the first protection unit 41 includes a third resistor R3, a fourth resistor R4 and a first transconductance amplifier U1, and the first current limiting unit 42 includes a fifth resistor R5; the power supply end of the first transconductance amplifier U1 is connected to the first filter resistor R S1 The first end of the first transconductance amplifier U1 is connected to the first end of the third resistor R3, the second input end of the first transconductance amplifier U1 is connected to the reference power supply end Ref, the output end of the first transconductance amplifier U1 is connected to the first end of the fifth resistor R5, the second end of the fifth resistor R5 is connected to the first end of the second switch unit 32, the first end of the fifth resistor R5 is connected to the ground end of the control circuit 10, the first end of the third resistor R3 is connected to the first end of the fourth resistor R4, the second end of the fourth resistor R4 is connected to the output end of the first transconductance amplifier U1, and the second end of the third resistor R3 is connected to the first filter resistor R S1 The first end.

[0093] The first transconductance amplifier U1 is used to convert voltage into current, and the withstand voltage of the first transconductance amplifier U1 can be changed by changing the ratio of the resistance value of the third resistor R3 to the resistance value of the fourth resistor R4.

[0094] Specifically, when the breakdown voltage of the control circuit 10 is 16V, the voltage at point A can be set to 1V, and the voltage of the reference voltage Ref can also be set to 1V. When the ratio of the resistance value of the third resistor R3 to the resistance value of the fourth resistor R4 is 13, the withstand voltage of the first transconductance amplifier U1 is 14V. When the voltage between the first power supply terminal P+ and the second power supply terminal P- is greater than 14V, the first transconductance amplifier U1 will generate a current discharge between the first power supply terminal P+ and the second power supply terminal P-, and a voltage drop will be formed at the fifth resistor R5. At this time, the voltage at the ground terminal of the control circuit 10 is greater than 0V, so that the voltage at the control terminal of the first switch module 20 is greater than 0V. At this time, the third transistor NM0 cannot be completely turned off, and then, there is a large current between the charger and the ground, and the current flows along the first power supply terminal P+ to the first filter resistor R S1The discharge current is discharged from the first transconductance amplifier U1 to the fifth resistor R5 to the second switch unit 32 to the first switch module 20 to the ground. When the discharge current is greater than the maximum current of the charger, the voltage between the first power supply terminal P+ and the second power supply terminal P- will be clamped at the breakdown voltage of the protection module 40, thereby protecting the control circuit 10.

[0095] Figure 8 FIG. 1 is a schematic diagram of another charge and discharge protection circuit according to an embodiment of the present invention. Figure 8 On the basis of the above embodiments, optionally, the first switch module includes a third transistor NM0; the first switch unit 31 includes a first switch S1, and the second switch unit 32 includes a second switch S2. The control end of the third transistor NM0 is connected to the control circuit 10, the first electrode of the third transistor NM0 is connected to the negative electrode of the battery BAT and connected to the second end of the first switch S1, the second electrode of the third transistor NM0 is connected to the second power supply terminal P- and connected to the second end of the second switch S2, the first end of the first switch S1 is connected to the first end of the second switch S2, and the first end of the second switch S2 is connected to the second end of the fifth resistor R5.

[0096] Specifically, when the first transconductance amplifier U1 is turned on, a large current between the charger and the ground flows along the first power supply terminal P+ to the first filter resistor R S1 The path from the first transconductance amplifier U1 to the fifth resistor R5 to the second switch S2 to the third transistor NM0 to the ground is used for discharge.

[0097] By setting a first diode, a first Zener diode series circuit or a first transconductance amplifier, and matching a current limiting resistor, when the charging voltage at both ends of the battery is too high, it is broken down to protect the control circuit, and the current limiting resistor makes the voltage at the ground end of the control circuit greater than 0V, so that the first transistor cannot be completely turned off, providing a discharge path for the larger discharge current in the loop. Improve the reliability of the analog power chip based on the control circuit, and improve the operating stability and safety reliability of the battery. And the circuit structure is simple and easy to implement.

[0098] Fig. 9 FIG. 1 is a schematic diagram of another charge and discharge protection circuit according to an embodiment of the present invention. Fig. 9 Based on the above embodiments, optionally, the charge and discharge protection circuit includes a second filter resistor R S2 ; The power supply end of the control circuit 10 passes through the second filter resistor R S2Connected to the first power supply terminal P+; the second switch module 30 includes a third switch unit 33 and a fourth switch unit 34; the first end of the third switch unit 33 is connected to the first end of the fourth switch unit 34, the first end of the fourth switch unit 34 is connected to the ground end of the control circuit 10, the second end of the third switch unit 33 is connected to the first end of the first switch module 20, and the second end of the fourth switch unit 34 is connected to the second end of the first switch module 20.

[0099] Among them, the third switch unit 33 is used to transmit the first voltage at the first end of the first switch module 20 to the ground end of the control module 10 when it is turned on; the fourth switch unit 34 is used to transmit the second voltage at the second end of the first switch module 20 to the ground end of the control module 10 when it is turned on.

[0100] The protection module 40 includes a second protection unit 43 and a second current limiting unit 44; the control circuit 10 also includes an output terminal; the first terminal of the second protection unit 43 is connected to the second filter resistor R S2 The first end of the second protection unit 43 is connected to the first end of the second current limiting unit 44, the second end of the second current limiting unit 44 is connected to the output end of the control circuit 10, and the first end of the second current limiting unit 44 is connected to the control end of the first switch module 20.

[0101] The breakdown voltage of the second protection unit 43 is smaller than the breakdown voltage of the control circuit 10, and is used to be broken down when the charging voltage across the battery BAT is large, so as to protect the control circuit 10. The second current limiting unit 44 is used to limit the current when the second protection unit 43 is broken down.

[0102] Fig.10 FIG. 1 is a schematic diagram of another charge and discharge protection circuit according to an embodiment of the present invention. Fig.10 On the basis of the above embodiments, optionally, the second protection unit 43 includes a second diode D2, and the second current limiting unit 44 includes a sixth resistor R6; the first electrode of the second diode D2 is connected to the second filter resistor R S2 The first end of the second diode D2 is connected to the first end of the sixth resistor R6, the second end of the sixth resistor R6 is connected to the output end of the control circuit 10, and the first end of the sixth resistor R6 is connected to the control end of the first switch module 20.

[0103] The second diode D2 may be any PN junction formed by a process.

[0104] Fig.11 FIG. 1 is a schematic diagram of another charge and discharge protection circuit according to an embodiment of the present invention. Fig.11On the basis of the above embodiments, optionally, the first switch module 20 includes a third transistor NM0; the third switch unit 33 includes a third switch S3, and the fourth switch unit 34 includes a fourth switch S4. The control end of the third transistor NM0 is connected to the first end of the sixth resistor R6, the first electrode of the third transistor NM0 is connected to the negative electrode of the battery BAT and connected to the second end of the third switch S3, the second electrode of the third transistor NM0 is connected to the second power supply terminal P- and connected to the second end of the fourth switch S4, the first end of the third switch S3 is connected to the first end of the fourth switch S4, and the first end of the fourth switch S4 is connected to the ground end of the control module 10.

[0105] Combination Figures 9 to 11 Specifically, since the breakdown voltage of the second diode D2 is lower than the breakdown voltage of the control circuit 10, the second diode D2 will be broken down when the charging voltage at both ends of the battery BAT is large. When the second diode D2 is broken down, the current flows to the control end of the first switch module 20, and a voltage drop is formed at the sixth resistor R6. At this time, the voltage at the control end of the first switch module 20 is greater than 0V, so that the first switch module 20 cannot be completely turned off. As a result, the large current between the charger and the ground flows along the first power supply terminal P+ to the second filter resistor R S2 The discharge current is discharged through the path from the second diode D2 to the sixth resistor R6 through the inside of the control circuit 10 to the ground terminal of the control circuit 10 to the fourth switch S4 to the third transistor NM0 to the ground. When the discharge current is greater than the maximum current of the charger, the voltage between the first power terminal P+ and the second power terminal P- will be clamped at the breakdown voltage of the protection module 40, thereby protecting the control circuit 10.

[0106] Fig.12 FIG. 1 is a schematic diagram of another charge and discharge protection circuit according to an embodiment of the present invention. Fig.12 On the basis of the above embodiment, optionally, the second protection unit 43 includes at least two second Zener diodes Z2, the second current limiting unit 44 includes a seventh resistor R7; at least two second Zener diodes Z2 are connected in series; the first end of the at least two second Zener diode series circuit is connected to the second filter resistor R S2 The first end of the at least two second Zener diode series circuits is connected to the first end of the seventh resistor R7, the second end of the seventh resistor R7 is connected to the output end of the control circuit 10, and the first end of the seventh resistor R7 is connected to the control end of the first switch module 20. Among them, the at least two second Zener diode series circuits are used to be broken down when the charging voltage at both ends of the battery BAT is large to protect the control circuit 10. The number of the second Zener diodes Z2 is determined by the maximum withstand voltage of the control circuit 10. Fig.12 exemplarily shows that the at least two second Zener diodes include two second Zener diodes Z2.

[0107] Fig.13 FIG. 1 is a schematic diagram of another charge and discharge protection circuit according to an embodiment of the present invention. Fig.13 On the basis of the above embodiments, optionally, the first switch module 20 includes a third transistor NM0; the third switch unit 33 includes a third switch S3, and the fourth switch unit 34 includes a fourth switch S4. The control end of the third transistor NM0 is connected to the first end of the seventh resistor R7, the first electrode of the third transistor NM0 is connected to the negative electrode of the battery BAT and connected to the second end of the third switch S3, the second electrode of the third transistor NM0 is connected to the second power supply terminal P- and connected to the second end of the fourth switch S4, the first end of the third switch S3 is connected to the first end of the fourth switch S4, and the first end of the fourth switch S4 is connected to the ground end of the control module 10.

[0108] refer to Fig.12 and Fig.13 Specifically, when at least two second Zener diode series circuits are broken down, a large current between the charger and the ground flows along the first power supply terminal P+ to the second filter resistor R S2 The electric power is discharged through a path from the second Zener diode Z2 to the seventh resistor R7 through the interior of the control circuit 10 to the ground terminal of the control circuit 10 to the fourth switch S4 to the third transistor NM0 to the ground.

[0109] Fig.14 FIG. 1 is a schematic diagram of another charge and discharge protection circuit according to an embodiment of the present invention. Fig.14 On the basis of the above embodiment, optionally, the second protection unit 43 includes an eighth resistor R8, a ninth resistor R9 and a second transconductance amplifier U2, and the second current limiting unit 44 includes a tenth resistor R10; the power supply end of the second transconductance amplifier U2 is connected to the second filter resistor R S2 The first end of the second transconductance amplifier U2 is connected to the first end of the eighth resistor R8, the second input end of the second transconductance amplifier U2 is connected to the reference power supply end Ref, the output end of the second transconductance amplifier U2 is connected to the first end of the tenth resistor R10, the second end of the tenth resistor R10 is connected to the output end of the control circuit 10, the first end of the tenth resistor R10 is connected to the control end of the first switch module 20, the first end of the eighth resistor R8 is connected to the first end of the ninth resistor R9, the second end of the ninth resistor R9 is connected to the output end of the second transconductance amplifier U2, and the second end of the eighth resistor R8 is connected to the second filter resistor R S2 The first end.

[0110] Fig.15 FIG. 1 is a schematic diagram of another charge and discharge protection circuit according to an embodiment of the present invention. Fig.15On the basis of the above embodiments, optionally, the first switch module 20 includes a third transistor NM0; the third switch unit 33 includes a third switch S3, and the fourth switch unit 34 includes a fourth switch S4. The control end of the third transistor NM0 is connected to the first end of the tenth resistor R10, the first electrode of the third transistor NM0 is connected to the negative electrode of the battery BAT and connected to the second end of the third switch S3, the second electrode of the third transistor NM0 is connected to the second power supply terminal P- and connected to the second end of the fourth switch S4, the first end of the third switch S3 is connected to the first end of the fourth switch S4, and the first end of the fourth switch S4 is connected to the ground end of the control module 10.

[0111] refer to Fig.14 and Fig.15 Specifically, when the breakdown voltage of the control circuit 10 is 16V, the voltage at point A1 can be set to 1V, and the voltage of the reference voltage Ref is also set to 1V. When the ratio of the resistance value of the eighth resistor R8 to the resistance value of the ninth resistor R9 is 13, the withstand voltage of the second transconductance amplifier U2 is 14V. When the voltage between the first power supply terminal P+ and the second power supply terminal P- is greater than 14V, the second transconductance amplifier U2 will generate a current discharge between the first power supply terminal P+ and the second power supply terminal P-, and a voltage drop will be formed at the tenth resistor R10. At this time, the voltage at the ground terminal of the control circuit 10 is greater than 0V, so that the voltage at the control terminal of the third transistor NM0 is greater than 0V. At this time, the third transistor NM0 cannot be completely turned off, and then, the large current between the charger and the ground flows along the first power supply terminal P+ to the second filter resistor R S2 The discharge current is discharged through the path from the second transconductance amplifier U2 to the tenth resistor R10 through the control circuit to the ground terminal of the control circuit 10 to the fourth switch S4 to the third transistor NM0 to the ground. When the discharge current is greater than the maximum current of the charger, the voltage between the first power supply terminal P+ and the second power supply terminal P- will be clamped at the breakdown voltage of the protection module 40, thereby protecting the control circuit 10.

[0112] By setting a second diode, a second Zener diode series circuit or a second transconductance amplifier, and matching a current limiting resistor, when the charging voltage at both ends of the battery is too high, it is broken down to protect the control circuit, and the current limiting resistor makes the voltage at the ground end of the control circuit greater than 0V, so that the first transistor cannot be completely turned off, providing a discharge path for the larger discharge current in the loop. Improve the reliability of the analog power chip based on the control circuit, and improve the operating stability and safety reliability of the battery. And the circuit structure is simple and easy to implement.

[0113] Fig.16 FIG. 1 is a schematic diagram of another charge and discharge protection circuit according to an embodiment of the present invention. Fig.16On the basis of the above embodiments, optionally, the charge and discharge protection circuit also includes a power supply voltage generating circuit 50; the power supply end of the control circuit 10 is connected to the first power supply end P+ through the power supply voltage generating circuit 50, and the power supply voltage generating circuit 50 is used to provide power to the control circuit 10.

[0114] Since the devices used by the protection module 40 and the control circuit 10 are different, the breakdown voltage is also different, so that the well potentials connected on the layout are different, which will lead to a large layout area of ​​the analog power chip and a corresponding high manufacturing cost. It should be noted that here, the breakdown voltage of the control circuit 10 is the breakdown voltage of the analog power chip. When the devices used by the protection module 40 and the control circuit 10 are different, the well of the protection module 40 is different from the well of the control circuit 10, that is, the well of the protection module 40 is different from the well of the analog power chip. Therefore, separating the power supply of the control circuit 10 and the protection module 40 can effectively avoid the above problems. The following is a detailed description of how to reduce the layout area of ​​the battery charging and discharging circuit.

[0115] Specifically, a power supply voltage generating circuit 50 is provided, and a new power supply is generated by the power supply voltage generating circuit 50 to power the control circuit 10. Since the control circuit 10 is powered by the voltage VDD1 output by the power supply voltage generating circuit 50, and the voltage VDD1 is less than the power supply voltage VDD, the voltage at the power supply end of the control circuit 10 is less than the voltage at the power supply end of the protection module 40. At this time, the control circuit 10 and the protection module 40 can use devices with the same breakdown voltage. Therefore, when performing layout design, the same well can be used, thereby reducing the layout area, that is, reducing the layout area of ​​the analog power chip based on the battery charge and discharge protection circuit, and reducing the manufacturing cost. At the same time, since the voltage VDD1 input to the control circuit 10 is less than the power supply voltage VDD of the protection module 40, when the charging voltage at both ends of the battery BAT is too large, the control circuit 10 can be further protected.

[0116] The technical solution of the embodiment of the present invention is to set a control circuit to detect the voltage at both ends of the battery, and control the conduction state of the first switch module according to the detected voltage, so as to cut off the charging path when the voltage at both ends of the battery is too high and cut off the discharging path when the battery is over-discharged, thereby protecting the battery and extending the service life of the battery. By setting the breakdown voltage of the protection module to be lower than the breakdown voltage of the control circuit, when the charging voltage at both ends of the battery is too high, the control circuit is protected to prevent the excessive voltage from continuing to be transmitted to the control circuit, avoid the control circuit from being damaged by breakdown due to the excessive voltage, and avoid high-voltage surges at both ends of the battery, thereby improving the reliability of the analog power chip and improving the working stability and safety reliability of the battery. By setting the power supply end of the power supply voltage generating circuit to be connected to the power supply end of the protection module, the power supply voltage generating circuit and the protection module can use devices with the same breakdown voltage, and the voltage generated by the power supply voltage generating circuit is used to power the control circuit and the voltage is less than the power supply voltage. At this time, the control circuit and the protection module use devices with the same breakdown voltage to protect the control circuit. At this time, the well potential of the control circuit is the same as the well potential of the protection module, that is, the well potential of the analog power chip is the same as the well potential of the protection module, thereby reducing the layout area of ​​the analog power chip based on the battery charge and discharge protection circuit and reducing the manufacturing cost.

[0117] Fig.17 FIG. 1 is a schematic diagram of a power supply voltage generating circuit according to an embodiment of the present invention. Fig.17 On the basis of the above embodiments, optionally, the power supply voltage generating circuit 50 includes a fifth switch unit 51, a sixth switch unit 52, a current control unit 53 and an eleventh resistor R11; a first end of the current control unit 53 is connected to the first power supply terminal P+, a second end of the current control unit 53 is connected to the first end of the eleventh resistor R11, a first end of the eleventh resistor R11 is connected to the control end of the fifth switch unit 51, a first end of the fifth switch unit 51 is connected to the first power supply terminal P+, a second end of the fifth switch unit 51 is connected to the power supply terminal of the control circuit 10, a second end of the eleventh resistor R11 is connected to the first end of the sixth switch unit 52, a control end of the sixth switch unit 52 is connected to the negative electrode of the battery BAT, and a second end of the sixth switch unit 52 is connected to the ground end of the control circuit 10.

[0118] When the fifth switch unit 51 and the sixth switch unit 52 are both turned on, the current of the current control unit 53 flows through the eleventh resistor R11 and generates a voltage drop on the eleventh resistor R11, thereby affecting the bias voltage of the fifth switch unit 51 and generating a voltage VDD1.

[0119] Fig.18 FIG. 1 is a schematic diagram of another power supply voltage generating circuit provided according to an embodiment of the present invention. Fig.18On the basis of the above embodiments, optionally, the fifth switch unit 51 includes a first transistor NM1, and the sixth switch unit 52 includes a second transistor NM2; the control electrode of the first transistor NM1 is connected to the second end of the current control unit 53, the first electrode of the first transistor NM1 is connected to the first power supply terminal P+, the second electrode of the first transistor NM1 is connected to the power supply terminal of the control circuit 10, the control electrode of the second transistor NM2 is connected to the negative electrode of the battery BAT, the first electrode of the second transistor NM2 is connected to the second end of the eleventh resistor R11, and the second electrode of the second transistor NM2 is connected to the ground terminal of the control circuit 10. The second transistor NM2 and the first transistor NM1 function as switches.

[0120] Specifically, by setting the breakdown voltage of the first transistor NM1 and the breakdown voltage of the second transistor NM2 to be the same as the breakdown voltage of the protection module 40, and the first electrode of the first transistor NM1 and the power supply end of the protection module 40 are both connected to the power supply voltage VDD, therefore, the well potential of the first transistor NM1 is the same as the well potential of the protection module 40, so when performing layout design, they can be arranged close to each other, thereby reducing the layout area, that is, the layout area of ​​the analog power chip based on the battery charge and discharge protection circuit can be reduced, and the manufacturing cost can be reduced.

[0121] Continue to refer Fig.18 Optionally, the current control unit 53 includes a current mirror A1; a first end of the current mirror A1 is connected to the first power supply terminal P+, a second end of the current mirror A1 is connected to the control end of the fifth switch unit 51, and is connected to the first end of the eleventh resistor R11.

[0122] The current mirror A1 is used to generate a voltage drop on the eleventh resistor R11 when current flows through the eleventh resistor R11, thereby affecting the bias voltage of the first transistor NM1. The current mirror A1 can be implemented using any existing circuit structure, and this embodiment does not specifically limit it.

[0123] Specifically, when the first power supply terminal P+ and the second power supply terminal P- are connected to the charger, the control circuit 10 controls the voltage of its ground terminal to be negative, so that the second transistor NM2 is in the on state. The voltage of the first pole of the first transistor NM1 is the power supply voltage VDD, and the current of the current mirror A1 flows through the eleventh resistor R11 to generate a voltage drop, so that the bias voltage provided to the first transistor NM1 is reduced, and the voltage VDD1 output by the second pole of the first transistor NM is less than the power supply voltage VDD, and the control circuit 10 is powered by the voltage VDD1. Through this setting, it can be ensured that the voltage of the power supply terminal of the protection module is less than the voltage of the power supply terminal of the control circuit. When the protection module and the control circuit have the same breakdown voltage, the protection module will be broken down first to protect the control circuit, thereby improving the reliability of the analog power chip. And the structure is simple and easy to implement.

[0124] An embodiment of the present invention further provides a power simulation chip, including the battery charge and discharge protection circuit provided by any of the above embodiments. Therefore, the power simulation chip has corresponding beneficial effects.

[0125] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0126] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A charge and discharge protection circuit, characterized in that: include: A control circuit, a first switch module, a second switch module and a protection module; The power supply end of the control circuit is connected to the first power supply end, the first end of the first switch module is connected to the negative electrode of the battery, the positive electrode of the battery is connected to the first power supply end, and the second end of the first switch module is connected to the second power supply end. The control circuit is used to control the on or off of the first switch module according to the voltages at both ends of the battery; the ground end of the control circuit is connected to the first end of the second switch module, the second end of the second switch module is connected to the first end of the first switch module, and the third end of the second switch module is connected to the second end of the first switch module. The control circuit is also used to collect a first voltage at the first end of the first switch module and a second voltage at the second end of the first switch module, and output the smaller value of the first voltage and the second voltage to the ground end of the control circuit; The protection module is connected in parallel with the control circuit, and the breakdown voltage of the protection module is lower than the breakdown voltage of the control circuit; the protection module is used to protect the control circuit when the charging voltage at both ends of the battery is too large; Wherein, the first power supply terminal and the second power supply terminal are used to connect to a charger or a load.

2. The charge and discharge protection circuit according to claim 1, characterized in that: including a first filter resistor; The power supply end of the control circuit is connected to the first power supply end through the first filter resistor; The second switch module includes a first switch unit and a second switch unit; The first end of the first switch unit is connected to the first end of the second switch unit, the first end of the second switch unit is connected to the ground end of the control circuit, the second end of the first switch unit is connected to the first end of the first switch module, and the second end of the second switch unit is connected to the second end of the first switch module; The protection module includes a first protection unit and a first current limiting unit; The first end of the first protection unit is connected to the first end of the first filter resistor, the second end of the first protection unit is connected to the first end of the first current limiting unit, the second end of the first current limiting unit is connected to the first end of the second switch unit, and the first end of the first current limiting unit is connected to the ground end of the control circuit.

3. The charge and discharge protection circuit according to claim 2, characterized in that: The first protection unit includes a first diode, and the first current limiting unit includes a first resistor; The first electrode of the first diode is connected to the first end of the first filter resistor, the second electrode of the first diode is connected to the first end of the first resistor, the second end of the first resistor is connected to the first end of the second switch unit, and the first end of the first resistor is connected to the ground end of the control circuit.

4. The charge and discharge protection circuit according to claim 2, characterized in that: The first protection unit includes at least two first Zener diodes, and the first current limiting unit includes a second resistor; at least two of the first Zener diodes are connected in series; The first ends of at least two of the first Zener diode series circuits are connected to the first end of the first filter resistor, the second ends of at least two of the first Zener diode series circuits are connected to the first end of the second resistor, the second end of the second resistor is connected to the first end of the second switch unit, and the first end of the second resistor is connected to the ground end of the control circuit.

5. The charge and discharge protection circuit according to claim 2, characterized in that: The first protection unit includes a third resistor, a fourth resistor and a first transconductance amplifier, and the first current limiting unit includes a fifth resistor; A power supply terminal of the first transconductance amplifier is connected to a first end of the first filter resistor, a first input terminal of the first transconductance amplifier is connected to a first end of the third resistor, a second input terminal of the first transconductance amplifier is connected to a reference power supply terminal, an output terminal of the first transconductance amplifier is connected to a first end of the fifth resistor, a second end of the fifth resistor is connected to a first end of the second switch unit, a first end of the fifth resistor is connected to a ground terminal of the control circuit, a first end of the third resistor is connected to a first end of the fourth resistor, a second end of the fourth resistor is connected to the output terminal of the first transconductance amplifier, and a second end of the third resistor is connected to a first end of the first filter resistor.

6. The charge and discharge protection circuit according to claim 1, characterized in that: including a second filtering resistor; The power supply end of the control circuit is connected to the first power supply end through the second filter resistor; The second switch module includes a third switch unit and a fourth switch unit; The first end of the third switch unit is connected to the first end of the fourth switch unit, the first end of the fourth switch unit is connected to the ground end of the control circuit, the second end of the third switch unit is connected to the first end of the first switch module, and the second end of the fourth switch unit is connected to the second end of the first switch module; The protection module includes a second protection unit and a second current limiting unit; the control circuit also includes an output terminal; The first end of the second protection unit is connected to the first end of the second filter resistor, the second end of the second protection unit is connected to the first end of the second current limiting unit, the second end of the second current limiting unit is connected to the output end of the control circuit, and the first end of the second current limiting unit is connected to the control end of the first switch module.

7. The charge and discharge protection circuit according to claim 6, characterized in that: The second protection unit includes a second diode, and the second current limiting unit includes a sixth resistor; The first electrode of the second diode is connected to the first end of the second filter resistor, the second electrode of the second diode is connected to the first end of the sixth resistor, the second end of the sixth resistor is connected to the output end of the control circuit, and the first end of the sixth resistor is connected to the control end of the first switch module.

8. The charge and discharge protection circuit according to claim 6, characterized in that: The second protection unit includes at least two second Zener diodes, and the second current limiting unit includes a seventh resistor; at least two of the second Zener diodes are connected in series; The first ends of at least two of the second Zener diode series circuits are connected to the first ends of the second filter resistor, the second ends of at least two of the second Zener diode series circuits are connected to the first end of the seventh resistor, the second end of the seventh resistor is connected to the output end of the control circuit, and the first end of the seventh resistor is connected to the control end of the first switch module.

9. The charge and discharge protection circuit according to claim 6, characterized in that: The second protection unit includes an eighth resistor, a ninth resistor and a second transconductance amplifier, and the second current limiting unit includes a tenth resistor; The power supply terminal of the second transconductance amplifier is connected to the first end of the second filter resistor, the first input terminal of the second transconductance amplifier is connected to the first end of the eighth resistor, the second input terminal of the second transconductance amplifier is connected to the reference power supply terminal, the output terminal of the second transconductance amplifier is connected to the first end of the tenth resistor, the second end of the tenth resistor is connected to the output terminal of the control circuit, the first end of the tenth resistor is connected to the control terminal of the first switch module, the first end of the eighth resistor is connected to the first end of the ninth resistor, the second end of the ninth resistor is connected to the output terminal of the second transconductance amplifier, and the second end of the eighth resistor is connected to the first end of the second filter resistor.

10. The charge and discharge protection circuit according to claim 1, characterized in that: Also included is a power supply voltage generating circuit; The power supply end of the control circuit is connected to the first power supply end through the power supply voltage generating circuit, and the power supply voltage generating circuit is used to provide power to the control circuit.

11. The charge and discharge protection circuit according to claim 10, characterized in that: The power supply voltage generating circuit includes a fifth switch unit, a sixth switch unit, a current control unit and an eleventh resistor; The first end of the current control unit is connected to the first power supply end, the second end of the current control unit is connected to the first end of the eleventh resistor, the first end of the eleventh resistor is connected to the control end of the fifth switch unit, the first end of the fifth switch unit is connected to the first power supply end, the second end of the fifth switch unit is connected to the power supply end of the control circuit, the second end of the eleventh resistor is connected to the first end of the sixth switch unit, the control end of the sixth switch unit is connected to the negative electrode of the battery, and the second end of the sixth switch unit is connected to the ground end of the control circuit.

12. The charge and discharge protection circuit according to claim 11, characterized in that: The fifth switch unit includes a first transistor, and the sixth switch unit includes a second transistor; The control electrode of the first transistor is connected to the second end of the current control unit, the first electrode of the first transistor is connected to the first power supply end, the second electrode of the first transistor is connected to the power supply end of the control circuit, the control electrode of the second transistor is connected to the negative electrode of the battery, the first electrode of the second transistor is connected to the second end of the eleventh resistor, and the second electrode of the second transistor is connected to the ground end of the control circuit.

13. The charge and discharge protection circuit according to claim 11, characterized in that: The current control unit includes a current mirror; A first end of the current mirror is connected to the first power supply end, and a second end of the current mirror is connected to the control end of the fifth switch unit and to the first end of the eleventh resistor.

14. The charge and discharge protection circuit according to claim 1, characterized in that: The first switch module includes a third transistor; the control circuit also includes an output terminal; The control electrode of the third transistor is connected to the output end of the control circuit, the first electrode of the third transistor is connected to the negative electrode of the battery, and the second electrode of the third transistor is connected to the second power supply end.

15. An analog power chip, characterized in that: The invention comprises the charge and discharge protection circuit according to any one of claims 1 to 14.

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