CN111835071B - Protection circuit and system of battery - Google Patents
Protection circuit and system of battery Download PDFInfo
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- CN111835071B CN111835071B CN202010737068.3A CN202010737068A CN111835071B CN 111835071 B CN111835071 B CN 111835071B CN 202010737068 A CN202010737068 A CN 202010737068A CN 111835071 B CN111835071 B CN 111835071B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/0029—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits
- H02J7/00306—Overdischarge protection
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/007—Regulation of charging or discharging current or voltage
- H02J7/0071—Regulation of charging or discharging current or voltage with a programmable schedule
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Abstract
The invention provides a battery protection circuit and a battery protection system, wherein a timing unit controls an output signal of an output end of the timing unit according to a control instruction received by a communication end after a preset duration of a preset condition is met, so that the input end and the output end of a switch unit are controlled to be disconnected, the power supply output of a battery is disconnected, and the battery is prevented from continuously consuming power after being used up; meanwhile, after the power supply output of the battery is cut off, only a small leakage current exists in the switch unit, so that the excessive power consumption of the battery can be avoided, the over-discharge state of the battery is effectively prevented, and the over-discharge effect of the battery is protected; the current limiting unit, the switch unit, the timing unit and the like adopted in the invention have simple realization circuits and low hardware cost.
Description
Technical Field
The invention relates to the technical field of electronic industry, in particular to a battery protection circuit and system.
Background
A battery that is continuously used by activating an active material by charging after discharging is called a secondary battery. With the advent of the concept of sustainable development of resources, secondary batteries are widely used in daily life. When the battery discharges, the stored electric energy is gradually released, the voltage slowly drops, when the voltage drops to a certain specified value, the discharge should be stopped, and if the discharge is continued, the over discharge is caused. Over-discharge is very likely to damage the cell chemistry leading to cell deactivation, which in turn leads to non-reuse until scrapped.
In order to avoid over-discharge, the over-discharge protection circuit of the lithium battery in the prior art, as shown in fig. 1, includes: a reference voltage generation module 101, a voltage detection module 102, a voltage comparison module 103, a switch module 104 and a load protection module 105; the circuit determines whether to shut down the external power supply of the battery by judging whether the voltage reaches a preset protection threshold value of the reference voltage so as to execute protection and achieve the aim of preventing the over-discharge of the lithium battery. However, the reference voltage generation module 101, the voltage detection module 102 and the voltage comparison module 103 used in the circuit consume more battery energy in the circuit, and the battery still needs to be continuously powered after entering an over-discharge protection state, so that a small-capacity lithium battery or a button battery is easily over-discharged; in addition, the scheme has the advantages of complex realization circuit, fussy control and higher hardware cost.
Disclosure of Invention
In view of this, embodiments of the present invention provide a battery protection circuit and system to solve the problems of the conventional protection circuit that the battery energy consumption is large, the small-capacity battery is easy to generate an overdischarge state, the circuit is complex, and the hardware cost is high.
In order to achieve the above purpose, the embodiments of the present invention provide the following technical solutions:
the present invention in a first aspect provides a battery protection circuit, comprising: the device comprises a current limiting unit, a switching unit and a timing unit; wherein:
the current limiting unit is arranged in a charge-discharge branch of the battery;
the input end of the switch unit is connected with the positive electrode of the charging and discharging branch circuit, the output end of the switch unit is connected with the power supply end of the timing unit, the grounding end of the switch unit, the grounding end of the timing unit and the negative electrode of the charging and discharging branch circuit are grounded, and the control end of the switch unit is connected with the output end of the timing unit;
the communication end of the timing unit receives a control instruction, and the control instruction is used for controlling an output signal of the timing unit, so that the timing unit controls the input end and the output end of the switch unit to be disconnected through the output signal of the timing unit after the timing unit meets the preset duration of the preset condition, and the power supply output of the battery is disconnected.
Optionally, the preset condition is that an application system of the protection circuit of the battery is shut down.
Optionally, the timing unit further includes: an additional input end for receiving a charging detection signal of the charging and discharging branch; wherein:
the preset condition is that the charging detection signal represents that the charging and discharging branch circuit does not receive charging electric energy of a power supply.
Optionally, the current limiting unit includes: a first resistor;
the first resistor is connected between the positive electrode of the battery and the positive electrode of the charge-discharge branch circuit.
Optionally, the switch unit includes: the circuit comprises a first switching tube, a second switching tube, a third switching tube, a fourth switching tube, a second resistor, a third resistor, a fourth resistor and a fifth resistor; wherein:
the first switching tube, the second switching tube, the third switching tube and the fourth switching tube are all switching tubes with anti-parallel diodes;
the input end of the first switch tube is connected with one end of the second resistor, and the connection point is used as the input end of the switch unit;
the other end of the second resistor is connected with the control end of the first switching tube and the input end of the third switching tube respectively;
the output end of the first switch tube, one end of the third resistor, one end of the fourth resistor and the input end of the second switch tube are connected, and a connection point is used as a first output end of the switch unit and is used for being connected with a power supply end of the timing unit;
the control end of the third switch tube is connected with the other end of the third resistor, and a connection point is used as a control end of the switch unit and receives a Real Time Clock (RTC) power supply enabling signal;
the output end of the second switching tube is connected with one end of the fifth resistor, and the connection point is used as the second output end of the switching unit and used for supplying power to the GPS-RTC chip;
the control end of the second switching tube is connected with the other end of the fourth resistor and the input end of the fourth switching tube;
a control end of the fourth switching tube is connected with the other end of the fifth resistor, a connection point is used as the other control end of the switching unit, and a Global Positioning System (GPS) power supply enabling signal is received;
and the output ends of the third switching tube and the fourth switching tube are used as the grounding ends of the switching units.
Optionally, the timing unit includes a low power consumption timing chip and a peripheral circuit; wherein:
the VDD pin of the low-power consumption timing chip is connected with the power supply end of the timing unit through a corresponding device of the peripheral circuit;
the SCL pin and the SDL pin of the low-power-consumption timing chip are respectively connected with the communication end of the timing unit through corresponding devices of the peripheral circuit;
an INTRC pin of the low-power-consumption timing chip is connected with one output end of the timing unit and used for outputting a GPS power supply enabling signal;
an INTRB pin of the low-power-consumption timing chip is connected with the other output end of the timing unit and used for outputting an RTC power supply enabling signal;
and an OSCIN pin and an OSCOUT pin of the low-power consumption timing chip are respectively connected with a grounding end of the timing unit through corresponding devices of the peripheral circuit.
A second aspect of the present invention provides a battery protection system, including: a power supply, a Low Dropout Regulator (LDO), a first diode, a second diode, and a protection circuit of the battery as described above; wherein:
the anode of the power supply is connected with the input end of the LDO, and the cathode of the power supply is grounded;
the output end of the LDO is respectively connected with the anode of the first diode and the anode of the second diode;
the negative end of the first diode is connected with the positive electrode of a charge-discharge branch circuit in the protection circuit and is used for charging the battery;
and the cathode end of the second diode is connected with the second output end of the switch unit in the protection circuit and used for supplying power to the timing unit through corresponding devices in the switch unit.
Optionally, the LDO is a voltage regulation chip and a peripheral circuit; wherein:
a VDD pin of the voltage regulation chip is connected with an input end of the LDO through a corresponding device in the peripheral circuit;
and a VOUT pin of the voltage regulation chip is used as an output end of the LDO.
According to the protection circuit of the battery, the timing unit controls the output signal of the output end of the timing unit according to the control instruction received by the communication end after the preset duration of the preset condition is met, so that the input end and the output end of the switching unit are controlled to be disconnected, the power supply output of the battery is disconnected, and the battery is prevented from continuously consuming power after being used up; in addition, the protection circuit does not need a reference voltage generation module, a voltage detection module and a voltage comparison module, and only a small leakage current exists in the switch unit after the power supply output of the battery is cut off, so that the excessive power consumption of the battery can be avoided, the over-discharge state of the battery is effectively prevented, and the function of protecting the over-discharge of the battery is achieved; the current limiting unit, the switch unit, the timing unit and the like adopted in the invention have simple realization circuits and low hardware cost.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
Fig. 1 is a lithium battery over-discharge protection circuit disclosed in the prior art;
fig. 2 is a schematic structural diagram of a protection circuit of a battery according to the present invention;
fig. 3 is a diagram of a simulated output of a protection circuit for a battery according to the present invention;
fig. 4 is another schematic structural diagram of a battery protection circuit according to the present invention;
fig. 5 is a schematic structural diagram of a battery protection system according to the present invention;
fig. 6 is another schematic structural diagram of a battery protection system according to the present invention;
fig. 7 is another analog output diagram of a battery protection circuit according to the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In this application, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
The invention provides a battery protection circuit, which aims to solve the problems that the existing protection circuit consumes more battery energy, so that a small-capacity battery is easy to generate an over-discharge state, the circuit is complex and the hardware cost is high.
Referring to fig. 2, the protection circuit of the battery includes: a current limiting unit 201, a switching unit 202, and a timing unit 203; wherein:
the current limiting unit 201 is disposed in the charging and discharging branch 205 of the battery 204, and is used for dividing voltage and preventing the battery 204 from being damaged due to excessive current during charging and discharging.
Optionally, the current limiting unit may be a resistor (e.g., R1 in fig. 5), or may be other structures capable of implementing a voltage dividing function, such as at least two resistors connected in series, which is not limited herein, and the structures capable of implementing corresponding functions are all within the protection scope of the present application.
Input terminal a of switching unit 2021An output terminal A of the switching unit 202 connected to the positive terminal of the charging and discharging branch 2052And a power supply terminal B of the timing unit 2031Ground terminal A of switch unit 2024And a ground terminal B of the timing unit 2034And the negative electrode of the charge and discharge branch 205 is grounded.
Control terminal A of switch unit 2023And output B of timing unit 2032Connected to control input terminal A of switch unit 202 according to the output signal of timing unit 2031And an output terminal A2The connection state therebetween. Specifically, if the output signal outputted from the timing unit 203 is the input terminal a of the control switch unit 2021And an output terminal A2The battery 204 is connected with the load to realize the power supply output of the battery 204; if the output signal from the timing unit 203 is the input terminal A of the control switch unit 2021And an output terminal A2The battery 204 is disconnected from the load, and the power supply output of the battery 204 is finished.
Communication terminal B of timing unit 2033Receiving a control instruction, the control instruction being used to control the output signal of the timing unit 203, so that the timing unit 203 controls the input end a of the switch unit 202 through its own output signal after the preset duration of the preset condition is met1And an output terminal A2And disconnects the power supply output of the battery 204.
It is noted that the control command can be sent from the side B communicating with the timing unit 203 via the I2C interface3The CPU (Central Processing Unit) connected to the CPU (such as the CPU in fig. 6) may also be sent by other interfaces and other processor modules, but is not limited thereto, and in practical applications, the device capable of sending the control instruction may be determined according to the specific application environment, and all devices are within the protection scope of the present application.
The preset condition is used to trigger the timing unit 203 to execute a corresponding action in a specific state, and in practical application, the preset condition may be set according to a specific situation, which is not specifically limited herein. Optionally, the preset condition is that an application system of the protection circuit of the battery is shut down, and the system may be shut down under any condition. Referring to fig. 3, wherein SCL is the clock line of the processor I2C interface, communication terminal B connecting the processor and the timing unit 2033For clocking I2C communications; SDA is data line of processor I2C interface, communication end B connecting processor and timing unit 2033For transmitting data for I2C communications; as shown in FIG. 3, when the system is shut down, the timing unit 203, the time refresh cannot be obtained, the preset condition is satisfied, and then, when the preset duration T of the timing unit 203 is reached, the input terminal a of the switch unit 202 can be controlled1And an output terminal A2Are disconnected. Fig. 3 shows that the input terminal a of the switch unit 202 is controlled when the output signal of the timing unit 203 is at a high level1And an output terminal A2While the output signal of the timing unit 203 is at low level controls the input terminal a of the switch unit 2021And an output terminal A2The switching between the first and second signals is shown as an example, and in practical applications, the level control result of the output signal of the timing unit 203 may also be changed in accordance with the selection of the corresponding device in the switch unit 202, which is not specifically limited herein.
The preset time T is calculated according to the capacity and the discharge capacity of the battery 204 and the actual power consumption capacity of the load, and may also be defined according to the time requirement of a special product, and in actual application, the preset time T may be set according to the specific application environment.
Preferably, the specific obtaining process of the preset time length T in this embodiment is as follows: the preset time period T is obtained as C/I in unit h according to the actual capacity C (in mAh) of the battery 204 and the current consumption I (in mA) of the load.
Optionally, the timing Unit 203 may be a low power consumption timing chip, or an IC (Integrated Circuit) with a timing function, or a Circuit such as an RTC (Microprogrammed Control Unit) or an MCU (Microprogrammed Control Unit), which is not limited to this.
Optionally, referring to fig. 4, the timing unit 203 further includes: additional input terminal B5For receiving the charging detection signal of the charging and discharging branch 205; at this time, there is a power source 206 to supply power to the charging and discharging branch 205 and the timing unit 203, and the preset condition is that the charging detection signal indicates that the charging and discharging branch 205 does not receive the charging power of the power source 206, for example, the battery 204 is disconnected from the host. When the power supply of the power source 206 is removed, the charging detection signal triggers the timing unit 203 to reach a preset condition, and then reaches the preset conditionAfter the preset duration, the timing unit 203 controls the input terminal a of the switch unit 2021And an output terminal A2The connection is disconnected, the battery 204 is prevented from being discharged continuously, and the over-discharge protection of the battery 204 is realized.
In the protection circuit for a battery provided in this embodiment, the timing unit 203 controls the output signal according to the received control command, and after the preset duration of the preset condition is met, the output signal controls the input terminal a of the switch unit 2021And an output terminal A2The connection is broken, and the power supply output of the battery 204 is disconnected, so that the battery 204 is prevented from continuously discharging; in addition, the protection circuit does not need a reference voltage generation module, a voltage detection module and a voltage comparison module, and only a small leakage current exists in the switch unit 202 after the power supply output of the battery 204 is cut off, so that excessive power consumption of the battery 204 can be avoided, the battery 204 is effectively prevented from entering an overdischarge state, the battery 204 is maximally utilized, and the use reliability of the battery 204 is enhanced; meanwhile, the current limiting unit 201, the switch unit 202 and the timing unit 203 adopted by the scheme have simple circuits, and the hardware cost is reduced.
Referring to fig. 5, the present invention further provides an embodiment of a battery protection circuit, wherein the current limiting unit 201 is a first resistor R1, and the first resistor R1 is connected between the positive electrode of the battery 204 and the positive electrode of the charging/discharging branch 205.
The switching unit 202 includes: a first switch tube Q1, a second switch tube Q2, a third switch tube Q3, a fourth switch tube Q4, a second resistor R2, a third resistor R3, a fourth resistor R4 and a fifth resistor R5; wherein:
the first switching tube Q1, the second switching tube Q2, the third switching tube Q3 and the fourth switching tube Q4 are all switching tubes with anti-parallel diodes.
The input end of the first switch tube Q1 is connected to one end of the second resistor R2, and the connection point is used as the input end of the switch unit 202, and receives the power supplied by the charge-discharge branch 205 or the power supply BAT +.
The other end of the second resistor R2 is respectively connected with the control end of the first switching tube Q1 and the input end of the third switching tube Q3; the output end of the first switch tube Q1, one end of the third resistor R3, one end of the fourth resistor R4, and the input end of the second switch tube Q2 are connected, and the connection point is used as the first output end of the switch unit 202 and is connected to the power supply terminal 3V3D _ RTC of the timing unit 203.
The control terminal of the third switch transistor Q3 is connected to the other terminal of the third resistor R3, and the connection point is used as a control terminal of the switch unit 202 and receives the RTC power supply enable signal RTC _ VDD _ CTL. The output end of the second switch tube Q2 is connected to one end of the fifth resistor R5, and the connection point is used as the second output end of the switch unit 202, and is connected to the power supply 3V3D _ GPS _ RTC for supplying power to the GPS-RTC chip.
The control end of the second switch tube Q2 is connected to the other end of the fourth resistor R4 and the input end of the fourth switch tube Q4. The control end of the fourth switch tube Q4 is connected to the other end of the fifth resistor R5, and the connection point is used as the other control end of the switch unit 202, and receives the GPS power supply enable signal GPS _ VDD _ CTL.
The output terminals of the third switch tube Q3 and the fourth switch tube Q4 are used as the ground terminals of the switch unit 202.
The timing unit 203 comprises a low-power-consumption timing chip U1 and peripheral circuits; wherein:
the VDD pin of the low-power-consumption timing chip U1 is connected with the power supply terminal 3V3D _ RTC of the timing unit 203 through the corresponding device 501 of the peripheral circuit; the SCL pin of the low power consumption timing chip U1 is connected to the communication terminal I2C0_ SCL of the timing unit 203 through the corresponding device 502 of the peripheral circuit, and the SDL pin thereof is connected to the communication terminal I2C0_ SDA of the timing unit 203 through the corresponding device 506 of the peripheral circuit.
An INTRC pin of the low-power-consumption timing chip U1 is connected with a first output end of the timing unit 203 and is used for outputting a GPS power supply enabling signal GPS _ VDD _ CTL; an INTRB pin of the low power consumption timing chip U1 is connected to a second output terminal of the timing unit 203, and is configured to output an RTC power supply enable signal RTC _ VDD _ CTL.
According to the difference of the power consumption of the GPS-RTC chip hot start and the low-power consumption timing chip U1 (such as an RTC chip), the backup power supply of the GPS-RTC chip hot start and the self power supply of the low-power consumption timing chip U1 can be cut off successively.
The OSCIN pin and the OSCOUT pin of the low power consumption timing chip U1 are connected to the ground terminal of the timing unit 203 through the corresponding devices 503 of the peripheral circuit, respectively.
The simulation process of this embodiment in DSP software is as follows:
in the first case: the timing unit 203 of the protection circuit has no additional input B5See fig. 2 and 3:
after the circuit is started, the processor sends an instruction of outputting a high level output signal and turning over the output signal to a low level after a preset time length T and starting timing from the current time every time the timing unit 203 is polled, so that real-time updating of data in the timing unit 203 is realized.
When the analog program starts, the output signal of the timing unit 203 is continuously at a high level, when the timing unit 203 cannot obtain time refresh due to system shutdown, the timing unit 203 is triggered to execute a command of "start timing from now", and when a preset time length T is reached, the output signal of the timing unit 203 is inverted to a low level, so as to accurately control the input end a of the switch unit 202 in the protection circuit1And an output terminal A2The connection is broken, and the over-discharge phenomenon of the battery 204 is prevented.
In the second case: the timing unit 203 of the protection circuit has an additional input B5See fig. 4 and 7:
after the circuit is started, the processor only needs to send the timing unit 203 a single time to continuously monitor the additional input B by sending the output signal high5After a preset time T, the output signal is inverted to a low level, and an additional input end B is arranged at the timing unit5And when the level state of (1) is a low level, the timing command is started, and the data in the timing unit 203 is updated in real time without repeated transmission.
At the beginning of the simulation procedure, the output signal of the timing unit 203 and the additional input B5The level state of (B) is continuously high level, and when the power source 206 is pulled out, that is, the charging detection signal indicates that the charging/discharging branch 205 does not receive the charging power of the power source 206, the additional input terminal B of the timing unit 2035Is turned over to low level, touchesThe timing unit 203 executes the instruction of 'timing from now on', when the preset time length T is reached, the output signal of the timing unit is inverted to low level, and the input end A of the switch unit 202 in the protection circuit is accurately controlled1And an output terminal A2The connection is broken, and the over-discharge phenomenon of the battery 204 is prevented.
Referring to fig. 6, the present invention also provides a battery protection system, including: a power supply 601, a low dropout regulator LDO602, a first diode D1, a second diode D2, and a battery protection circuit 603; wherein:
the anode of the power supply 601 is connected to the input end of the LDO602, and is used for supplying power to the protection circuit 603; the negative pole of the power supply 601 is grounded.
The output terminal of the LDO602 is connected to the anode of the first diode D1 and the anode of the second diode D2, respectively, for transmitting the electric power of the power source 601 for the connected devices, i.e., for supplying power to the switch unit 202 and the timing unit 203.
The cathode of the first diode D1 is connected to the anode of the charging and discharging branch 205 in the protection circuit 603, and is used for charging the battery 204; the cathode of the second diode D2 is connected to the second output terminal (the connection point of the second switch Q2 and the fifth resistor R5 in fig. 5) of the switch unit 202 in the protection circuit 603, and the timing unit 203 is powered by the corresponding device in the switch unit 202, i.e. the backward diode of the second switch Q2 in fig. 5.
It is worth noting that after the power source 601 is installed, the power source 601 is converted into the voltage required by the timing unit 203 and the battery 204 through the LDO602, wherein a portion of the voltage is charged to the battery 204 through the first diode D1 and the current limiting unit 201 until the battery is fully charged; another portion powers the timing unit 203 through a second diode D2.
Specifically, referring to fig. 5 on the basis of fig. 6, the LDO602 is a voltage regulation chip 504 and a peripheral circuit; wherein:
the VDD pin of the voltage regulation chip 504 is connected with the input end of the LDO602 through a corresponding device 505 in the peripheral circuit; the VOUT pin of the voltage regulation chip 504 serves as the output of the LDO 602.
Based on fig. 5 and fig. 6, the specific implementation process of the battery protection system is as follows:
when the timing unit 203 is used in this embodiment without an additional input B5The timing unit 203 updates in real time, and receives a command that the control output signal sent by the processor is at a high level and is turned into a low level after the current timing is started and the preset time length is reached. Referring to fig. 3, when the system is turned off, the timing unit 203 starts timing; when the timing unit 203 employed in this embodiment is a band add input B5The timing unit 203 receives the control output signal sent by the processor, and the control output signal is high level and continuously focuses on the additional input end B5At the additional input terminal B5When the level state of the charging/discharging branch 205 is a low level, the timing unit 203 starts timing by controlling the output signal to be inverted to a low level command after the timing is started and the preset time duration is reached, and after the power source 601 is removed, the charging detection signal is triggered to represent the preset condition that the charging/discharging branch 205 does not receive the charging power of the power source 601.
After the low power consumption timing chip U1 starts timing, when a preset time period T is reached, the INTRC pin and INTRB pin of the low power consumption timing chip are controlled to turn over to a low level, at this time, the control terminal voltages of the third switching tube Q3 and the fourth switching tube Q4 are pulled low, the third switching tube Q3 and the fourth switching tube Q4 are cut off, and the control terminal voltages of the first switching tube Q1 and the second switching tube Q2 are pulled high by the second resistor R2 and the fourth resistor R4, at this time, the control terminal voltages of the first switching tube Q1 and the second switching tube Q2 are higher than the input terminal voltage, and then the first switching tube Q1 and the second switching tube Q2 are cut off, resulting in the input terminal a of the switching unit 202 turning over to a low level1And an output terminal A2When the connection is disconnected, and the timing unit 203 is powered down, the control terminals of the third switching tube Q3 and the fourth switching tube Q4 are continuously locked at a low level, so that the first switching tube Q1 and the second switching tube Q2 are always in an off state, and the battery 204 cannot supply power to the outside, thereby cutting off the battery 204 in real time, and effectively preventing the overdischarge phenomenon of the battery 204. At this time, only the reverse diode of the first switch tube Q1 and the second switch tube Q2 and the reverse leakage current of the first diode D1 exist in the circuit, and the sum of the leakage currents is far less than 0.05uA, thereby ensuring that the current leakage currents are not too largeProves at input terminal A of switch unit 2021And an output terminal A2The discharge of the battery 204 after the disconnection is close to zero, greatly reducing the risk of the battery 204 entering an overdischarge state.
If the switch unit 202 in the protection circuit 603 needs to be reactivated, the power source 601 needs to be reinstalled/connected, so that the power source 601 supplies power to the timing unit 203 through the LDO602 and the second diode D2, so that the output end of the timing unit 203 outputs a high level, that is, the GPS power supply enable signal GPS _ VDD _ CTL and the RTC power supply enable signal RTC _ VDD _ CTL are high level signals, and then the control end voltages of the third switch tube Q3 and the fourth switch tube Q4 are pulled high, the third switch tube Q3 and the fourth switch tube Q4 are turned on, while the control end voltages of the first switch tube Q1 and the second switch tube Q2 are pulled low by the third switch tube Q3 and the fourth switch tube Q4, the first switch tube Q1 and the second switch tube Q2 are also turned on, and the input end a of the switch unit 202 is connected1And an output terminal A2The connection is made, and a path for supplying power to the timing unit 203 by the battery 204 is opened, so that the connection between the battery 204 and the load is realized.
The battery protection system provided in this embodiment may monitor the real-time status of the battery 204 by using the processor software to refresh the start time of the timing unit 203 in real time, or by using an external trigger, such as manually changing the output signal of the timing unit 203, so that the timing unit 203 controls the input terminal a of the switch unit 202 after reaching the preset time period T1And an output terminal A2The connection is disconnected, so that the over-discharge protection of the battery 204 is realized; in addition, excessive hardware is not needed in the process, the hardware cost is reduced, the circuit is simple, and the complexity of the circuit is reduced.
The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, the system or system embodiments are substantially similar to the method embodiments and therefore are described in a relatively simple manner, and reference may be made to some of the descriptions of the method embodiments for related points. The above-described system and system embodiments are only illustrative, wherein the units described as separate parts may or may not be physically separate, and the parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.
Those of skill would further appreciate that the various illustrative components and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both, and that the components and steps of the various examples have been described above generally in terms of their functionality in order to clearly illustrate this interchangeability of hardware and software. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (7)
1. A protection circuit for a battery, comprising: the device comprises a current limiting unit, a switching unit and a timing unit; wherein:
the current limiting unit is arranged in a charge-discharge branch of the battery;
the input end of the switch unit is connected with the positive electrode of the charging and discharging branch circuit, the output end of the switch unit is connected with the power supply end of the timing unit, the grounding end of the switch unit, the grounding end of the timing unit and the negative electrode of the charging and discharging branch circuit are grounded, and the control end of the switch unit is connected with the output end of the timing unit;
the communication end of the timing unit receives a control instruction, and the control instruction is used for controlling an output signal of the timing unit, so that the timing unit controls the input end and the output end of the switch unit to be disconnected through the output signal of the timing unit after the timing unit meets the preset duration of the preset condition, and the power supply output of the battery is disconnected;
the switching unit includes: the circuit comprises a first switching tube, a second switching tube, a third switching tube, a fourth switching tube, a second resistor, a third resistor, a fourth resistor and a fifth resistor; wherein:
the first switching tube, the second switching tube, the third switching tube and the fourth switching tube are all switching tubes with anti-parallel diodes;
the input end of the first switch tube is connected with one end of the second resistor, and the connection point is used as the input end of the switch unit;
the other end of the second resistor is connected with the control end of the first switching tube and the input end of the third switching tube respectively;
the output end of the first switch tube, one end of the third resistor, one end of the fourth resistor and the input end of the second switch tube are connected, and a connection point is used as a first output end of the switch unit and is used for being connected with a power supply end of the timing unit;
the control end of the third switching tube is connected with the other end of the third resistor, and a connection point is used as a control end of the switching unit and receives an RTC power supply enabling signal;
the output end of the second switching tube is connected with one end of the fifth resistor, and the connection point is used as the second output end of the switching unit and used for supplying power to the GPS-RTC chip;
the control end of the second switching tube is connected with the other end of the fourth resistor and the input end of the fourth switching tube;
the control end of the fourth switching tube is connected with the other end of the fifth resistor, and the connection point is used as the other control end of the switching unit and receives a GPS power supply enabling signal;
and the output ends of the third switching tube and the fourth switching tube are used as the grounding ends of the switching units.
2. The battery protection circuit of claim 1, wherein the predetermined condition is an application system shutdown of the battery protection circuit.
3. The battery protection circuit of claim 1, wherein the timing unit further comprises: an additional input end for receiving a charging detection signal of the charging and discharging branch; wherein:
the preset condition is that the charging detection signal represents that the charging and discharging branch circuit does not receive charging electric energy of a power supply.
4. The battery protection circuit according to any one of claims 1 to 3, wherein the current limiting unit includes: a first resistor;
the first resistor is connected between the positive electrode of the battery and the positive electrode of the charge-discharge branch circuit.
5. The battery protection circuit according to any one of claims 1 to 3, wherein the timing unit comprises a low power consumption timing chip and a peripheral circuit; wherein:
the VDD pin of the low-power consumption timing chip is connected with the power supply end of the timing unit through a corresponding device of the peripheral circuit;
the SCL pin and the SDL pin of the low-power-consumption timing chip are respectively connected with the communication end of the timing unit through corresponding devices of the peripheral circuit;
an INTRC pin of the low-power-consumption timing chip is connected with one output end of the timing unit and used for outputting a GPS power supply enabling signal;
an INTRB pin of the low-power-consumption timing chip is connected with the other output end of the timing unit and used for outputting an RTC power supply enabling signal;
and an OSCIN pin and an OSCOUT pin of the low-power consumption timing chip are respectively connected with a grounding end of the timing unit through corresponding devices of the peripheral circuit.
6. A system for protecting a battery, comprising: a power supply, a low dropout regulator (LDO), a first diode, a second diode, and a protection circuit for a battery according to any of claims 1-5; wherein:
the anode of the power supply is connected with the input end of the LDO, and the cathode of the power supply is grounded;
the output end of the LDO is respectively connected with the anode of the first diode and the anode of the second diode;
the cathode of the first diode is connected with the anode of a charge-discharge branch circuit in the protection circuit and is used for charging the battery;
and the cathode of the second diode is connected with the second output end of the switch unit in the protection circuit and used for supplying power to the timing unit through corresponding devices in the switch unit.
7. The battery protection system of claim 6, wherein the LDO is a voltage regulation chip and a peripheral circuit; wherein:
a VDD pin of the voltage regulation chip is connected with an input end of the LDO through a corresponding device in the peripheral circuit;
and a VOUT pin of the voltage regulation chip is used as an output end of the LDO.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202010737068.3A CN111835071B (en) | 2020-07-28 | 2020-07-28 | Protection circuit and system of battery |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202010737068.3A CN111835071B (en) | 2020-07-28 | 2020-07-28 | Protection circuit and system of battery |
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| CN111835071B true CN111835071B (en) | 2022-05-17 |
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| CN114050626B (en) * | 2021-11-25 | 2024-03-08 | 沃太能源股份有限公司 | Power-down protection circuit and electronic equipment with same |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH07170673A (en) * | 1993-12-15 | 1995-07-04 | Mitsubishi Electric Corp | Overdischarge prevention circuit |
| JP2001145271A (en) * | 1999-11-11 | 2001-05-25 | Mitsumi Electric Co Ltd | Secondary battery protection method and circuit |
| JP5083588B2 (en) * | 2006-03-31 | 2012-11-28 | 日立工機株式会社 | Lithium battery pack |
| US8194061B2 (en) * | 2007-08-09 | 2012-06-05 | Ee Systems Group Inc. | Process and system of power saving lighting |
| JP2009077510A (en) * | 2007-09-20 | 2009-04-09 | Hitachi Ltd | Charging/discharging circuit for electrolytic capacitor |
| US9231283B2 (en) * | 2009-01-14 | 2016-01-05 | Mitsumi Electric Co., Ltd. | Protection monitoring circuit, battery pack, secondary battery monitoring circuit, and protection circuit |
| CN103647323A (en) * | 2013-12-13 | 2014-03-19 | 海能达通信股份有限公司 | Cell discharge overcurrent protection circuit and cell discharge overcurrent protection method |
| CN206649317U (en) * | 2017-03-15 | 2017-11-17 | 比亚迪股份有限公司 | Portable electric appts and the on/off circuit for it |
| CN109687541A (en) * | 2017-10-19 | 2019-04-26 | 新盛力科技股份有限公司 | Battery powdered device |
| CN107994891A (en) * | 2017-11-16 | 2018-05-04 | 北京奇虎科技有限公司 | A kind of time-delay shutdown circuit and electronic equipment |
| KR102259413B1 (en) * | 2018-03-12 | 2021-06-01 | 주식회사 엘지에너지솔루션 | Apparatus for preventing over-discharge |
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