CN210957863U

CN210957863U - Charging double-protection circuit

Info

Publication number: CN210957863U
Application number: CN201922245042.2U
Authority: CN
Inventors: 吴军良
Original assignee: Wuyi Jinghong Electronic Technology Co ltd
Current assignee: Wuyi Jinghong Electronic Technology Co ltd
Priority date: 2019-12-16
Filing date: 2019-12-16
Publication date: 2020-07-07
Anticipated expiration: 2029-12-16

Abstract

The utility model provides a dual protection circuit charges, including control chip group, charge-discharge control switch, battery parameter acquisition circuit and the second grade protection circuit that charges, its characterized in that: the control chip set is respectively connected to the charge-discharge control switch, the battery pack, the battery parameter acquisition circuit and the secondary protection circuit, a secondary charge protection IC is added on the basis of the original lithium battery protection board, the secondary charge MOS is controlled independently, the voltage of the lithium battery is detected independently by two ICs unrelated to the primary charge protection, and the charge MOS is controlled independently. One of the charging MOS can be switched off when any one of the primary charging protection MOS and the secondary charging protection MOS is short-circuited, and charging is cut off, so that the safety and reliability of lithium battery charging are ensured.

Description

Charging double-protection circuit

Technical Field

The utility model relates to a protection circuit field charges especially relates to a duplicate protection circuit charges.

Background

With the increasing demand for portability of electronic products, more and more electronic products using batteries as power supplies have increased demands for the service life of batteries, and rechargeable batteries are generally used to delay the service life of electronic products.

In the process of charging the battery, if the electric quantity of the battery is fully charged, if the battery is not detected and controlled, the battery is continuously charged and is in an overcharged state for a long time, the aging phenomenon of the battery can be caused, and the service life of the battery is greatly reduced. In the prior art, a charging protection circuit generally uses a charging dedicated control chip, and some low-cost charging protection circuits have no consideration on the aspect of battery overcharge protection.

A lithium ion battery is a secondary battery (rechargeable battery) that mainly operates by movement of lithium ions between a positive electrode and a negative electrode. During charging and discharging, Li + is repeatedly inserted and extracted between two polar ends, during charging, Li + is extracted from a positive electrode and inserted into a negative electrode through an electrolyte, and the negative electrode is in a lithium-rich state; the opposite is true during discharge. The lithium ion battery is an energy storage device widely applied in the fields of consumer electronics and power energy storage, and in order to prevent the damage and even the safety accident of the lithium ion battery when overcharging occurs in abnormal use, the lithium ion battery is provided with a protection circuit in actual use, and the protection circuit generally has the functions of overcharge protection and the like.

At present, a lithium ion battery protection circuit mainly includes a determination circuit (typically, an IC chip and a resistor capacitor) for detecting a voltage and a current of a lithium ion battery, and a switching element (typically, a MOS transistor) for turning off/on a charging circuit. When the lithium ion battery or one of the single batteries is abnormal, the chip in the judging circuit gives judgment through the collected voltage and current information, and different control signals are output at the corresponding control end to control the corresponding MOS tube to switch off the charging loop, so that the safety of the lithium ion battery is protected.

In conventional protection circuit, conventional lithium cell protection shield charging protection only one-level, this kind of protection shield if meet the MOS pipe short circuit that charges, lithium cell charging reaches single section 4.2V, and the MOS that charges has short circuit this moment, so unable normal turn-off charge, so the lithium cell just has overcharge this moment and causes the safety risk of firing, explosion.

SUMMERY OF THE UTILITY MODEL

The embodiment of the utility model is realized like this:

the utility model provides a dual protection circuit charges, includes control chip group, charge-discharge control switch, battery parameter acquisition circuit and the secondary protection circuit that charges which characterized in that: the control chip set is respectively connected to the charge-discharge control switch, the battery pack, the battery parameter acquisition circuit and the secondary protection circuit.

In some embodiments of the present invention, the charge and discharge control circuit includes charge switches Q1 and Q2 connected in series between a charging power source and a positive electrode of the battery pack, Q1 and Q2 are P-type field effect transistors, wherein a drain of Q1 is connected in series with a source of Q2, a source of Q1 is connected to the charging power source, a drain of Q2 is connected to the positive electrode of the battery pack, zener diodes are connected in parallel to the sources and drains of Q1 and Q2, cathodes of the zener diodes are connected to the sources of Q1 and Q2, anodes of the zener diodes are connected to the drains of Q1 and Q2, and a drain of Q2 is connected to the negative electrode B-of the battery pack.

The utility model discloses an in some embodiments, battery parameter acquisition circuit connect in parallel in on the group battery, adopt MAX1906 chip for gather the charge-discharge current and the battery voltage of battery.

The utility model discloses an in some embodiments, control chip group includes rechargeable battery protection control chip BM3451 for the voltage, charging current and the ambient temperature information that detect each section battery realize the function that the battery overcharged and put the short circuit, and the positive terminal that each section battery of group battery was inserted respectively to its voltage input end VC1-VC5 detects the voltage and the charging current situation of current battery, rechargeable battery protection control chip BM 3451's output pin CO passes through the triode and inserts Q1's grid.

In some embodiments of the utility model, the second grade protection circuit includes second grade charge protection chip BM3051A, wherein, the VC1-VC5 pin of second grade charge protection chip BM3051A is connected to respectively rechargeable battery protection control chip BM 3451's VC1-VC5 pin, the VCC pin of second grade focus protection chip BM3051A inserts rechargeable battery protection control chip BM 3451's cascade control input pin DOIN and COIN.

In some embodiments of the present invention, the secondary charging protection circuit further includes a primary charging protection field effect transistor Q7 and a secondary charging protection field effect transistor Q6, wherein the primary charging protection field effect transistor Q7 is a P-type MOSFET, and the secondary charging protection field effect transistor Q6 is an N-type MOSFET.

In some embodiments of the utility model, the gate access of second grade charge protection field effect transistor Q7 the high level output pin CO of second grade charge protection chip BM3051A, source electrode access group battery negative pole B-, the drain electrode pass through resistance with the gate connection of the key protection field effect transistor Q7 of one-level.

In some embodiments of the present invention, the positive electrode of each lithium battery of the battery pack and the VC1-VC5 pin of the rechargeable battery protection control chip BM3451 chip are connected to a resistance-capacitance parallel circuit respectively, and the diode is reversely connected between the system voltage pin VCC of the rechargeable battery protection control chip BM3451 and the positive electrode B + of the battery pack.

In some embodiments of the present invention, the two segments of the input power source are connected to a diode to prevent the short circuit of the charging circuit.

The embodiment of the utility model provides an at least, have following advantage or beneficial effect:

1. a secondary charging protection IC is added on the basis of an original lithium battery protection board, a secondary charging MOS is independently controlled, the voltage of a lithium battery is independently detected by two ICs unrelated to the primary charging protection, and the charging MOS is independently controlled.

2. One of the charging MOS can be switched off when any one of the primary charging protection MOS and the secondary charging protection MOS is short-circuited, and charging is cut off, so that the safety and reliability of lithium battery charging are ensured.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention, and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

Fig. 1 is a schematic diagram of a charging dual protection circuit according to an embodiment of the present invention.

Fig. 2 is a schematic circuit diagram of a charging double protection circuit according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention, as generally described and illustrated in the figures herein, may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present invention, presented in the accompanying drawings, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

In the description of the embodiments of the present invention, it should be noted that, if the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the position or positional relationship based on the position or positional relationship shown in the drawings, or the position or positional relationship which is usually placed when the product of the present invention is used, the description is only for convenience of description of the present invention and simplification, but the indication or suggestion that the device or element to be referred must have a specific position, be constructed and operated in a specific position, and therefore, the present invention should not be construed as being limited thereto. Furthermore, the terms "first," "second," "third," and the like are used solely to distinguish one from another and are not to be construed as indicating or implying relative importance.

Furthermore, the terms "horizontal", "vertical", "overhang" and the like do not require that the components be absolutely horizontal or overhang, but may be slightly inclined. For example, "horizontal" merely means that the direction is more horizontal than "vertical" and does not mean that the structure must be perfectly horizontal, but may be slightly inclined.

In the description of the embodiments of the present invention, "a plurality" means at least 2.

In the description of the embodiments of the present invention, it should be further noted that unless explicitly stated or limited otherwise, the terms "disposed," "mounted," "connected," and "connected" should be interpreted broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.

Example 1

A charging double protection circuit comprises a control chip set, a charging and discharging control switch, a battery parameter acquisition circuit and a charging secondary protection circuit, wherein the control chip set is connected to the charging and discharging control switch, a battery pack, the battery parameter acquisition circuit and the secondary protection circuit respectively, as shown in figure 1.

The specific circuit is as shown in fig. 2, the charge and discharge control circuit comprises charge switches Q1 and Q2 connected in series between a charge power supply and the positive pole of the battery pack, the Q1 and the Q2 are P-type field effect transistors, wherein the drain of the Q1 is connected in series with the source of the Q2, the source of the Q1 is connected to the charge power supply, the drain of the Q2 is connected to the positive pole of the battery pack, a zener diode is connected in parallel with the sources and drains of the Q1 and the Q2, the cathode of the zener diode is connected to the sources of the Q1 and the Q2, the anode of the zener diode is connected to the drains of the Q1 and the Q2, and the drain of the Q2 is.

The utility model discloses an in some embodiments, second grade protection circuit includes second grade charge protection chip BM3051A, BM3451 is 3, 4, 5 section rechargeable battery's protection chip, through information such as the voltage that detects each section battery, charge-discharge current and ambient temperature, sight current overcharge, overdischarge, discharge overcurrent short circuit, charge overcurrent, work ability such as temperature protection, work is adjusted overcharge, overdischarge, overcurrent protection time delay through external electric capacity, the colleague provides battery capacity balance function, eliminate the capacity difference of each section battery in the group battery, the extension group battery life-span. The pins VC1-VC5 of the secondary charging protection chip BM3051A are respectively connected to the pins VC1-VC5 of the rechargeable battery protection control chip BM3451, and the pin VCC of the secondary emphasis protection chip BM3051A is connected to the cascade control input pins DOIN and COIN of the rechargeable battery protection control chip BM 3451.

The BM3451 chip can realize the cascade connection of a plurality of chips, thereby completing the protection of 6-section and easily-damaged battery packs.

In some embodiments of the utility model, the gate access of second grade charge protection field effect transistor Q6 the high level output pin CO of second grade charge protection chip BM3051A, source electrode access group battery negative pole B-, the drain electrode pass through resistance with the gate connection of the key protection field effect transistor Q7 of one-level.

Specifically, since the BM3051 is a rechargeable battery secondary protection chip with high precision, high integration level and low power consumption, when any pin of the detection circuit section VC1-VC5 detects that the battery voltage reaches a charging threshold, the charging threshold of the lithium battery is unobstructed to be 4.2V, and the chip delays T through overcharge protection_ovpAnd then, the chip output pin CO outputs a high level, at the moment, the secondary charging protection transistor Q6 receives the high level to be turned on, so that the primary charging protection transistor Q7 is turned on, and the charging switch Q2 is short-circuited and disconnected in the prior charging circuit.

When the battery pack generates an excessive temperature through charging, a high temperature signal is received by the temperature protection pins NTC and TRH of the BM3451, and the output CO of the BM3451 is turned off, so that the charging control switch Q1 is turned off, thereby turning off the entire charging circuit.

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. The utility model provides a dual protection circuit charges, includes control chip group, charge-discharge control switch, battery parameter acquisition circuit and the secondary protection circuit that charges which characterized in that: the control chip set is respectively connected to the charge-discharge control switch, the battery pack, the battery parameter acquisition circuit and the secondary protection circuit.

2. The charging dual protection circuit of claim 1, wherein the charging and discharging control circuit comprises charging switches Q1 and Q2 connected in series between a charging power source and a positive pole of a battery pack, the Q1 and the Q2 are both P-type field effect transistors, a drain of Q1 is connected in series with a source of Q2, a source of Q1 is connected to the charging power source, a drain of Q2 is connected to the positive pole of the battery pack, a zener diode is connected in parallel to the source and the drain of the Q1 and the Q2, a cathode of the zener diode is connected to the sources of Q1 and Q2, an anode of the zener diode is connected to the drains of the Q1 and the Q2, and a drain of the Q2 is connected to a negative pole B-of the battery pack.

3. The charging double protection circuit of claim 1, wherein the battery parameter collecting circuit is connected in parallel to the battery pack, and a MAX1906 chip is used for collecting the charging and discharging current and the battery voltage of the battery.

4. The charging double protection circuit according to claim 1, wherein the control chip set comprises a rechargeable battery protection control chip BM3451 for detecting the voltage, charging current and ambient temperature information of each battery to realize the function of short circuit of battery overcharge and overdischarge, voltage input terminals VC1-VC5 of the rechargeable battery protection control chip BM3451 are respectively connected to the positive terminals of each battery of the battery pack to detect the voltage and charging current conditions of the current battery, and an output pin CO of the rechargeable battery protection control chip BM3451 is connected to the gate of Q1 through a triode.

5. The charging double protection circuit of claim 1, wherein the secondary protection circuit comprises a secondary charging protection chip BM3051A, wherein the pins VC1-VC5 of the secondary charging protection chip BM3051A are respectively connected to the pins VC1-VC5 of the rechargeable battery protection control chip BM3451, and the pin VCC of the secondary emphasis protection chip BM3051A is connected to the cascade control input pins DOIN and COIN of the rechargeable battery protection control chip BM 3451.

6. The charging double protection circuit of claim 1, wherein the charging secondary protection circuit further comprises a primary charging protection field effect transistor Q7 and a secondary charging protection field effect transistor Q6, wherein the primary charging protection field effect transistor Q7 is a P-type MOSFET and the secondary charging protection field effect transistor Q6 is an N-type MOSFET.

7. The charging double protection circuit of claim 6, wherein the gate of the secondary charging protection FET Q7 is connected to the high level output pin CO of the secondary charging protection chip BM3051A, the source is connected to the cathode B-of the battery pack, and the drain is connected to the gate of the primary emphasis protection FET Q7 through a resistor.

8. The charging double protection circuit of claim 1, wherein a resistance-capacitance parallel circuit is connected between the positive electrode of each lithium battery of the battery pack and the pins VC1-VC5 of the rechargeable battery protection control chip BM3451, and a diode is reversely connected between the system voltage pin VCC of the rechargeable battery protection control chip BM3451 and the positive electrode B + of the battery pack.