Battery protection circuit and electronic equipment

Abstract

The utility model provides a battery protection circuit and electronic equipment. The battery protection circuit comprises a switch unit; the resistor is connected in series between the first end of the switch unit and the negative electrode of the battery, the second end of the switch unit is a load negative wiring terminal, and the positive electrode of the battery is a load positive wiring terminal; and the protection circuit is electrically connected with the resistor, the switch unit and the battery, and is used for acquiring a first voltage drop at the two ends of the resistor and a second voltage drop at the two ends of the switch unit, and controlling the switch unit to be switched off to protect the battery under the condition that the absolute value of the difference value of the first voltage drop and the second voltage drop is not in a preset voltage range. The voltage at the two ends of the precision resistor and the voltage at the two ends of the switch unit are compared in real time to obtain a difference value, when the absolute value of the difference value is not within a preset voltage range, the protection circuit judges that the protection board is abnormal, the protection circuit outputs a signal to close the switch unit and disconnect the output of the battery, so that the battery is protected.

Description

Technical Field

[0001] The present application relates to the technical field of battery charging, and in particular to a battery protection circuit and electronic equipment. Background Art

[0002] At present, the charging speed of electronic devices is getting faster and faster, and the charging power of batteries for charging electronic devices is getting higher and higher, from 50W to 100W, and even higher 120W. As the charging power increases, the battery and protection board generate more and more heat, and the probability of battery safety accidents increases. Therefore, the design of the battery protection board is particularly important.

[0003] The existing battery protection board design can only detect the battery cell voltage and the voltage across the precision resistor, and take corresponding protection actions according to the voltage changes. Once a problem occurs in the switch unit or the protection board circuit between the switch units, the protection IC cannot make a judgment and take protection action. Utility Model Content

[0004] The main purpose of the present application is to provide a battery protection circuit and electronic device to solve the problem in the prior art that once a problem occurs in the switch unit or the protection board circuit between the switch units, the protection IC cannot make a judgment and perform a protection action.

[0005] In order to achieve the above-mentioned purpose, according to one aspect of the present application, a battery protection circuit is provided, including: a switch unit; a resistor, connected in series between a first end of the switch unit and a negative electrode of a battery, a second end of the switch unit being a negative power supply output terminal, and a positive electrode of the battery being a positive power supply output terminal; a protection circuit, electrically connected to the resistor, the switch unit and the battery, respectively, the protection circuit being used to obtain a first voltage drop across the resistor and a second voltage drop across the switch unit, and controlling the switch unit to disconnect to protect the battery when the absolute value of the difference between the first voltage drop and the second voltage drop is not within a preset voltage range.

[0006] Furthermore, the switch unit includes a first switch tube and a second switch tube, and the resistor, the first switch tube and the second switch tube are connected in series in sequence. When the absolute value of the difference between the first voltage drop and the second voltage drop is not within the preset voltage range, the first switch tube and / or the second switch tube is controlled to be disconnected to protect the battery.

[0007] Further, the protection circuit includes a first protection module, the first protection module having pins VSS, VDD, VINI, VD, DO and CO, pin VSS of the first protection module is electrically connected to the first end of the resistor, pin VINI of the first protection module is electrically connected to the second end of the resistor, pin VD of the first protection module is electrically connected to the second end of the second switch tube, pins VSS and VINI of the first protection module are used to detect the first voltage drop, pins VINI and VD of the first protection module are used to detect the second voltage drop, pin VDD of the first protection module is connected to the positive electrode of the battery through a first pull-up resistor, and pins DO and CO of the first protection module are connected to the control end of the first switch tube.

[0008] Furthermore, the protection circuit includes a second protection module, the second protection module having pins VSS, VDD, VINI, DO and CO, pin VSS of the second protection module is grounded, pin VDD of the second protection module is connected to the positive electrode of the battery through a second pull-up resistor, pin VINI of the second protection module is electrically connected to the second end of the resistor, and pins DO and CO of the second protection module are connected to the control end of the second switch tube.

[0009] Furthermore, the protection circuit includes a protection resistor, a first end of the protection resistor is electrically connected to a pin VD of the first protection module, and a second end of the protection resistor is electrically connected to a second end of the second switch tube.

[0010] Furthermore, the protection circuit further includes a first capacitor module, and the first capacitor module is connected between a pin VSS and a pin VDD of the first protection module.

[0011] Furthermore, the protection circuit further includes a pull-down resistor, the first protection module further has a pin VM, a first end of the pull-down resistor is connected to the pin VM, and a second end of the pull-down resistor is electrically connected to the second end of the first switch tube.

[0012] Furthermore, the protection circuit further comprises a subtractor, a first input terminal and a second input terminal of the subtractor are respectively connected to a pin VINI and a pin VD of the first protection module, and an output terminal of the subtractor outputs the second voltage drop.

[0013] Furthermore, the protection circuit includes a voltage comparison unit, and the first input terminal and the second input terminal of the voltage comparison unit are respectively used to input a first voltage signal and a second voltage signal, the first voltage signal is a signal representing the absolute value of the difference between the first voltage drop and the second voltage drop, the second voltage signal is a signal representing the preset voltage range, and the output terminal of the voltage comparison unit is used to output a comparison result.

[0014] According to another aspect of the present application, an electronic device is provided, comprising: a battery and any one of the battery protection circuits connected to the battery.

[0015] By applying the technical solution of the present application, the voltage across the precision resistor and the voltage across the switch unit are compared in real time. If the absolute value of the voltage drop across the switch unit minus the voltage drop across the precision resistor is not within the preset voltage range, the protection circuit determines that the protection board is abnormal, and the protection circuit outputs a signal to turn off the switch unit and disconnect the battery output to protect the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings constituting part of the present application are used to provide a further understanding of the present application. The exemplary embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0017] Figure 1 A schematic diagram of a battery protection circuit according to an embodiment of the present application is shown;

[0018] Figure 2 A schematic diagram showing a voltage comparison unit and a subtractor of a battery protection circuit according to an embodiment of the present application is shown;

[0019] Figure 3 A schematic diagram of a battery protection circuit is shown;

[0020] Figure 4 A schematic diagram of the design of a first protection module of a battery protection circuit according to an embodiment of the present application is shown.

[0021] The above drawings include the following reference numerals:

[0022] 10. Switch unit; 11. First switch tube; 12. Second switch tube; 20. Resistor; 30. Protection circuit; 31. First protection module; 32. Second protection module; 40. Protection resistor; 50. First capacitor module; 60. Pull-down resistor; 70. Subtractor; 80. Voltage comparison unit; 90. Battery; 100. Pull-up resistor; 110. Second capacitor module. DETAILED DESCRIPTION

[0023] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0024] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0025] It should be understood that when an element (such as a layer, film, region, or substrate) is described as being "on" another element, the element may be directly on the other element, or there may be intermediate elements. Moreover, in the specification and claims, when an element is described as being "connected" to another element, the element may be "directly connected" to the other element, or "connected" to the other element through a third element.

[0026] For the convenience of description, some nouns or terms involved in the embodiments of the present application are explained below:

[0027] Protection IC: A component of an integrated circuit (IC) that protects the IC from voltage surges, overcurrent, overheating, and other conditions that may damage the IC. Protection ICs usually include overvoltage protection, overcurrent protection, overheating protection, short-circuit protection, and other functions to ensure that the IC can work properly and not be damaged under various operating conditions. Protection ICs play a very important role in electronic devices and can effectively protect the safety and stability of the IC and the entire circuit system.

[0028] As described in the background technology, in the prior art, once a problem occurs in the switch unit or the protection board circuit between the switch units, the protection IC cannot make a judgment and perform a protection action. In order to solve the above problem, this application proposes a battery protection circuit. Figure 1 and Figure 2 As shown, the battery protection circuit comprises:

[0029] Switch unit 10;

[0030] Among them, the switch unit 10 is a controllable switch unit; the controllable switch unit controls the on and off of the circuit through an external input signal to realize the switch control of the circuit. These devices can control the switch of high-power circuits, such as electromagnetic relays, transistors, field effect transistors, bidirectional thyristors, triacs, etc. The controllable switch unit can be applied to various electronic devices and systems, such as power supply control, motor control, lighting control, temperature control, etc. Its function is to provide a reliable and controllable method to control the switch of the circuit, thereby realizing the automatic control and intelligent management of the circuit.

[0031] The resistor 20 is connected in series between the first end of the switch unit 10 and the negative electrode of the battery 90, the second end of the switch unit 10 is the negative power output end, and the positive electrode of the battery 90 is the positive power output end;

[0032] Among them, resistor 20 is a precision resistor, which is used to accurately control the resistance value in the circuit. They usually have high accuracy and stability and can provide very accurate resistance values. This makes them widely used in circuits that require precise resistance values, such as in measuring instruments, precision instruments, electronic equipment and communication equipment. Through precision resistors, it is possible to ensure that the resistance value in the circuit is stable and reliable, thereby improving the performance and accuracy of the circuit.

[0033] The protection circuit 30 is electrically connected to the resistor 20, the switch unit 10 and the battery 90, respectively. The protection circuit 30 is used to obtain a first voltage drop across the resistor 20 and a second voltage drop across the switch unit 10, and when the absolute value of the difference between the first voltage drop and the second voltage drop is not within a preset voltage range, the switch unit 10 is controlled to disconnect to protect the battery 90.

[0034] Among them, Figure 1 As shown, after the positive power output terminal and the negative power output terminal are connected to the load, current will be generated in the battery protection circuit. The current flowing through the resistor 20 will generate a first voltage drop at both ends of the resistor, and the current flowing through the switch unit 10 will generate a second voltage drop at both ends of the switch unit.

[0035] For example, the preset voltage range is expressed as [|V0|-1mV, |V0|+1mV], where |V0| represents the absolute value of the difference between the first voltage drop and the second voltage drop when there is no abnormality;

[0036] For another example, the precision of the precision resistor is 1% and it is not easy to be damaged. Assume that RS=2mΩ is used here, the first switch tube 11 and the second switch tube 12 have the same specifications, the resistance RM1=RM2=3mΩ, and the resistance RL of the circuit on the protection board between BC=2Ω, then |V0|=|V1-V2|=|I×RS1-I×(RM1+RM2+RL)|=|2I-(3+3+2)I|=|2I-8I|=6ImV; V3=(|V0|±0.2I)=6I+0.2I=6.2I;

[0037] Abnormal state 1: When the second switch tube 12 has an abnormal resistance and increases to 5mΩ,

[0038] Then |V0|1=|V1-V2|=|I×RS1-I×(RM1+RM2+RL)|=|2I-(3+5+2)I|=|2I-10I|=8I mV;

[0039] |V0|1>V3=(6I+0.2I)mV=6.2I, CO and D0 of the first protection module 31 are protected and output a low level to turn off the first switch tube 11 to protect the battery 90 .

[0040] Abnormal state 2: The resistance RL of the circuit on the protection board between BC increases to 5mΩ, then:

[0041] |V0|2=|V1-V2|=|I×RS1-I×(RM1+RM2+RL)|=|2I-(3+3+5)I|=|2I-11I|=9ImV;

[0042] |V0|2>V3=(|V0|±0.2I)=6.2I, CO and D0 of the first protection module 31 output low level to turn off the first switch tube 11 to protect the battery 90.

[0043] Among them, the protection circuit 30 is used to protect the IC from voltage surges, overcurrent, overheating and other situations that may damage the IC. Protecting the IC usually includes functions such as overvoltage protection, overcurrent protection, overheating protection, short circuit protection, etc. to ensure that the IC can work normally and not be damaged under various working conditions. Protecting the IC plays a very important role in electronic equipment and can effectively protect the safety and stability of the IC and the entire circuit system.

[0044] In this embodiment, the voltage across the precision resistor is compared with the voltage across the switch unit in real time. If the absolute value of the voltage drop across the switch unit minus the voltage drop across the precision resistor is not within the preset voltage range, the first protection module 31 determines that the protection board is abnormal, and the protection IC immediately outputs a signal to turn off the switch unit and disconnect the battery output.

[0045] In an alternative approach, Figure 1 As shown, the switch unit 10 includes a first switch tube 11 and a second switch tube 12, and the resistor 20, the first switch tube 11 and the second switch tube 12 are connected in series in sequence. When the absolute value of the difference between the first voltage drop and the second voltage drop is not within the preset voltage range, the first switch tube 11 and / or the second switch tube 12 is controlled to be disconnected to protect the battery 90.

[0046] Specifically, Figure 1 As shown, by sequentially connecting the resistor 20, the first switch tube 11 and the second switch tube 12 in series, controlling the first switch tube 11 or the second switch tube 12 to disconnect can quickly protect the battery 90 and ensure the safety of the charging process.

[0047] In an alternative approach, Figure 1 As shown, the protection circuit 30 includes a first protection module 31, the first protection module 31 has a pin VSS, a pin VDD, a pin VINI, a pin VD, a pin DO and a pin CO, the pin VSS of the first protection module 31 is electrically connected to the first end of the resistor 20, the pin VINI of the first protection module 31 is electrically connected to the second end of the resistor 20, the pin VD of the first protection module 31 is electrically connected to the second end of the second switch tube 12, the pin VSS and the pin VINI of the first protection module 31 are used to detect the first voltage drop, the pin VINI and the pin VD of the first protection module 31 are used to detect the second voltage drop, the pin VDD of the first protection module 31 is connected to the positive electrode of the battery 90 through the first pull-up resistor 100, and the pin DO and the pin CO of the first protection module 31 are connected to the control end of the first switch tube 11. Specifically, the first protection module 31 realizes the control of the first switch tube 11 by connecting to the control end of the first switch tube 11.

[0048] In an alternative approach, Figure 1 As shown, the protection circuit 30 further includes a second protection module 32, the second protection module 32 has a pin VSS, a pin VDD, a pin VINI, a pin DO and a pin CO, the pin VSS of the second protection module 32 is grounded, the pin VDD of the second protection module 32 is connected to the positive electrode of the battery 90 through the second pull-up resistor 100, the pin VINI of the second protection module 32 is electrically connected to the second end of the resistor 20, and the pins DO and CO of the second protection module 32 are connected to the control end of the second switch tube 12. Specifically, the second protection module 32 realizes the control of the second switch tube 12 by connecting to the control end of the second switch tube 12.

[0049] In an alternative approach, Figure 1 As shown, the protection circuit 30 further includes a protection resistor 40, a first end of the protection resistor 40 is electrically connected to the pin VD of the first protection module 31, and a second end of the protection resistor 40 is electrically connected to the second end of the second switch tube 12. By electrically connecting the protection resistor 40 to the pin VD of the first protection module 31 and the second end of the second switch tube 12, a voltage division effect is achieved, and the circuit between the pin VD of the first protection module 31 and the second end of the second switch tube 12 is protected.

[0050] In an alternative approach, Figure 1 As shown, the protection circuit 30 further includes a first capacitor module 50, which is connected between the pin VSS and the pin VDD of the first protection module 31. By adding the first capacitor module 50 between the pin VSS and the pin VDD of the first protection module 31, a filtering effect is achieved.

[0051] In an alternative approach, Figure 1 As shown, the protection circuit 30 further includes a pull-down resistor 60, and the first protection module 31 further has a pin VM, a first end of the pull-down resistor 60 is connected to the pin VM, and a second end of the pull-down resistor 60 is electrically connected to the second end of the first switch tube 11. By adding a pull-down resistor 60 between the VM pin of the first protection module 31 and the second end of the first switch tube 11, the voltage "floating" to cause circuit instability is avoided.

[0052] In an alternative approach, Figure 1 and Figure 2 As shown, the protection circuit 30 also includes a subtractor 70, wherein the first input terminal and the second input terminal of the subtractor 70 are respectively connected to the pin VINI and the pin VD of the first protection module 31, and the output terminal of the subtractor 70 outputs the second voltage drop. By connecting the subtractor 70 to the pin VINI and the pin VD of the first protection module 31, the difference between the voltage measured in real time at the pin VINI and the voltage measured in real time at the pin VD can be obtained.

[0053] In an alternative approach, Figure 1 and Figure 2As shown, the protection circuit 30 further includes a voltage comparison unit 80, the first input terminal and the second input terminal of the voltage comparison unit 80 are respectively used to input a first voltage signal and a second voltage signal, the first voltage signal is a signal representing the absolute value of the difference between the first voltage drop and the second voltage drop, the second voltage signal is a signal representing the preset voltage range, and the output terminal of the voltage comparison unit 80 is used to output a comparison result, specifically, when the comparison result is a first value, it indicates that the absolute value of the difference between the first voltage drop and the second voltage drop is within the preset voltage range, and when the comparison result is a second value, it indicates that the absolute value of the difference between the first voltage drop and the second voltage drop is not within the preset voltage range. More specifically, the first value is 1 and the second value is 0; the above protection circuit 30 adds a voltage comparison unit 80, which can compare the absolute value of the difference between the first voltage drop and the second voltage drop with the preset voltage range and determine whether the absolute value of the difference between the first voltage drop and the second voltage drop is within the preset voltage range, and control the opening or closing of the first switch tube 11 through the comparison and judgment results, thereby protecting the safety of the circuit.

[0054] like Figure 1 As shown, the battery protection circuit of the present application also includes: a resistor R1, a second capacitor module 110, and a resistor R2. The first end of the resistor R1 is electrically connected to the positive electrode of the battery 90, and the second end is electrically connected to the second capacitor module 110; the first end of the second capacitor module 110 is grounded, and the second end is electrically connected to the resistor R1; the first end of the resistor R2 is connected to the pin VM of the second protection module 32, and the second end is electrically connected to the second end of the second switch tube 12; the specific connection method is as follows Figure 1 shown.

[0055] like Figure 1 As shown, the first protection module 31 of the embodiment of the present application is used as the secondary protection, and the second protection module 32 is used as the primary protection. Figure 3The difference of the battery protection circuit shown is that the newly added VD pin of the first protection module 31 of the embodiment of the present application is connected to the output terminal C position of the second switch tube 12 to detect the voltage V2 between BC, and the VINI pin is added to detect the voltage V1 between AB. AB is the two ends of the resistor 20, and BC is the two ends of the first switch tube 11 and the second switch tube 12 of the switch unit. Since the resistor RS and the first switch tube 11 and the second switch tube 12 are in series in the circuit, the current flowing through them when the protection board is working is the same and is set to I. Their resistances are RS1, RM1, and RM2 respectively. According to Ohm's law V=IR, when the current I passes through, the voltages at both ends of AB and BC are: V1=IRS1, V2=I(RM1+RM2+RL), and RL is the resistance of the circuit on the protection board between BC. Then |V1-V2|=|V0|, the internal logic of the first protection module 31 sets the voltage detected at the VD terminal to be not within the range of V3=(|V0|±0.21)mV, then CO, D0 of the first protection module 31 outputs a low level to turn off the first switch tube 11 to protect the battery 90. The difference between the battery 90 protection circuit of the embodiment of the present application and some other battery 90 protection circuits is that the battery 90 protection is further increased due to abnormal switch unit 10 or abnormal protection board circuit, so that the protection measures of the battery 90 are more complete and the safety of the battery 90 is greatly improved.

[0056] like Figure 4 The figure shows the design schematic diagram of the first protection module of the battery protection circuit, and the voltage detection function module required by the utility model is newly added, such as the dotted box part, and the pin is defined as VD. The VD terminal detects the voltage V2 of the VINI pin and the VD pin, and the VINI terminal detects the voltage V1 of the VSS pin and the VINI pin. At the same time, the voltage detection module compares V1 and V2, that is, |V2-V1|=|V0|, and according to the result of |V0|, the logic control module turns on or off CO and DO.

[0057] From the above description, it can be seen that the above embodiments of the present application achieve the following technical effects:

[0058] In the battery protection circuit of the present application, the voltage across the precision resistor is compared with the voltage across the switch unit in real time. If the absolute value of the voltage drop across the switch unit minus the voltage drop across the precision resistor is not within the preset voltage range, the protection circuit determines that the protection board is abnormal, and the protection circuit immediately outputs a signal to turn off the switch unit and disconnect the battery output. This solves the problem in the prior art that once there is a problem with the switch unit or the protection board circuit between the switch units, the protection circuit cannot make a judgment and perform a protection action.

[0059] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A battery protection circuit, characterized in that: include: Switching unit; A resistor is connected in series between the first end of the switch unit and the negative electrode of the battery, the second end of the switch unit is the negative power output end, and the positive electrode of the battery is the positive power output end; a protection circuit, electrically connected to the resistor, the switch unit and the battery, respectively, the protection circuit being used to obtain a first voltage drop across the resistor and a second voltage drop across the switch unit, and to control the switch unit to disconnect to protect the battery when an absolute value of a difference between the first voltage drop and the second voltage drop is not within a preset voltage range; Wherein, the switch unit includes a first switch tube and a second switch tube, the resistor, the first switch tube and the second switch tube are sequentially connected in series, and when the absolute value of the difference between the first voltage drop and the second voltage drop is not within the preset voltage range, the first switch tube and / or the second switch tube are controlled to be disconnected to protect the battery; The protection circuit includes a first protection module, the first protection module has pins VSS, VDD, VINI, VD, DO and CO, the pin VSS of the first protection module is electrically connected to the first end of the resistor, the pin VINI of the first protection module is electrically connected to the second end of the resistor, the pin VD of the first protection module is electrically connected to the second end of the second switch tube, the pins VSS and VINI of the first protection module are used to detect the first voltage drop, the pins VINI and VD of the first protection module are used to detect the second voltage drop, the pin VDD of the first protection module is connected to the positive electrode of the battery through a first pull-up resistor, and the pins DO and CO of the first protection module are connected to the control end of the first switch tube.

2. The battery protection circuit according to claim 1, characterized in that: The protection circuit includes a second protection module, which has pins VSS, VDD, VINI, DO and CO. Pin VSS of the second protection module is grounded, pin VDD of the second protection module is connected to the positive electrode of the battery through a second pull-up resistor, pin VINI of the second protection module is electrically connected to the second end of the resistor, and pins DO and CO of the second protection module are connected to the control end of the second switch tube.

3. The battery protection circuit according to claim 1, characterized in that: The protection circuit comprises a protection resistor, a first end of the protection resistor is electrically connected to a pin VD of the first protection module, and a second end of the protection resistor is electrically connected to a second end of the second switch tube.

4. The battery protection circuit according to claim 1, characterized in that: The protection circuit further includes a first capacitor module, and the first capacitor module is connected between a pin VSS and a pin VDD of the first protection module.

5. The battery protection circuit according to claim 1, characterized in that: The protection circuit further includes a pull-down resistor, and the first protection module further includes a pin VM, a first end of the pull-down resistor is connected to the pin VM, and a second end of the pull-down resistor is electrically connected to the second end of the first switch tube.

6. The battery protection circuit according to claim 1, characterized in that: The protection circuit further includes a subtractor, wherein a first input terminal and a second input terminal of the subtractor are respectively connected to a pin VINI and a pin VD of the first protection module, and an output terminal of the subtractor outputs the second voltage drop.

7. The battery protection circuit according to claim 1, characterized in that: The protection circuit includes a voltage comparison unit, wherein a first input terminal and a second input terminal of the voltage comparison unit are respectively used to input a first voltage signal and a second voltage signal, wherein the first voltage signal is a signal representing the absolute value of the difference between a first voltage drop and a second voltage drop, and the second voltage signal is a signal representing the preset voltage range, and an output terminal of the voltage comparison unit is used to output a comparison result.

8. An electronic device, characterized in that: include: A battery and a battery protection circuit according to any one of claims 1 to 7 connected to the battery.

Images