CN113676166A - Battery low-voltage automatic cut-off circuit and working method thereof - Google Patents
Battery low-voltage automatic cut-off circuit and working method thereof Download PDFInfo
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Abstract
The embodiment of the invention discloses a battery low-voltage automatic cut-off circuit and a working method thereof, wherein the circuit comprises: the device comprises a comparison unit, an electronic switch and a timing excitation unit; the comparison unit is used for acquiring the power supply voltage of an internal circuit of the equipment, and comparing the power supply voltage and the power supply voltage to output a level signal; the electronic switch is used for carrying out cutoff or conduction according to the level signal; and the timing excitation unit is internally provided with a mechanical switch and is used for transmitting the battery voltage to the electronic switch when the equipment is plugged in the power adapter and the mechanical switch is closed, and when the battery power is reduced to cause the internal power supply voltage of the equipment to be unstable or lower than the comparison voltage threshold value of the comparison unit, the comparison unit outputs a low level and the electronic switch is turned off. The circuit provided by the embodiment of the invention has the advantages of simple design, low cost, low shutdown current and maximized battery endurance time.
Description
Technical Field
The invention relates to the technical field of voltage cut-off circuits, in particular to a battery low-voltage automatic cut-off circuit and a working method thereof.
Background
Along with the development of modern electronic technology, people are to the continuous improvement of material life demand, portable equipment is like MIFI (Mobile router, Mobile Wifi), wireless routing, digital camera, wireless earphone, intercom, wireless mouse etc. have spread all over each trade, in order to make these portable equipment can carry to any place at any time and anywhere and use, all can be equipped with the lithium cell of a certain capacity, in the use, battery power can constantly reduce, when battery power reduces not enough in order to provide the current-voltage of demand for equipment, equipment can be in unstable state, equipment just need turn off the battery power supply line.
The current battery turn-off circuit is mainly realized by comparing and calculating the voltage of a battery, specifically, the voltage of the battery is connected with the input end of a hysteresis comparator after being divided by a plurality of high-precision resistors, when the voltage of the battery is lower than a negative threshold value of the hysteresis comparator, the hysteresis comparator outputs a low level, a grid electrode of an MOS electronic switch between the battery and an equipment circuit board receives the low level output by the hysteresis comparator, an MOS tube is not conducted, and thus the circuit connection between the battery and an internal circuit is cut off; only when the battery is charged to a voltage larger than the forward threshold value of the hysteresis comparator, the hysteresis comparator outputs a high level again to enable the MOS electronic switch, and the equipment can continue to work. The hysteresis comparator is a comparator with hysteresis function built by an operational amplifier, and the hysteresis function is needed because the battery has a voltage difference between the power-on state and the power-off state.
However, the hysteresis comparator needs to be built by a discrete element, a voltage reference, a hysteresis function and an operational amplifier are used, circuit components are multiple, circuits are complicated, and because a voltage division value needs to be calculated by a resistor, the precision has deviation, and the cut-off and recovery voltage values of a battery have deviation; in order to ensure the stability of the circuit, the set battery voltage shutdown point also needs to artificially increase the safety interval of voltage, and when the battery is shut down, part of electric quantity of the battery is not used actually, so that the actual endurance time of the equipment is reduced; in addition, because the hysteresis comparator is powered by the power supply voltage, when the equipment is turned off, leakage current still exists, and the discharge loss of the battery can be accelerated until the battery is over-discharged for protection.
Therefore, it is necessary to design a new circuit to solve the above disadvantages of the circuit.
Disclosure of Invention
The invention aims to provide a battery low-voltage automatic cut-off circuit and a working method thereof.
In order to solve the technical problems, the invention aims to realize the following technical scheme: provided is a battery low voltage automatic cut-off circuit, including: the device comprises a comparison unit, an electronic switch and a timing excitation unit; a mechanical switch is arranged in the timing excitation unit; the electronic switch, the mechanical switch and the timing excitation unit are respectively connected with a battery, wherein the comparison unit is used for acquiring the power supply voltage of an internal circuit of the equipment and comparing the power supply voltage to output a level signal; the electronic switch is used for carrying out cutoff or conduction according to the level signal; the timing excitation unit is used for transmitting the battery voltage to the electronic switch when the equipment is plugged in the power adapter and the mechanical switch is closed, and when the battery power is reduced to cause the internal power supply voltage of the equipment to be unstable or lower than the comparison voltage threshold value of the comparison unit, the comparison unit outputs low level, and the electronic switch is turned off.
The further technical scheme is as follows: the power supply device is characterized by further comprising a first switching power supply unit and a second switching power supply unit, wherein the first switching unit is connected with the second switching power supply, and one end of the electronic switch is connected between the first switching power supply unit and the second switching power supply unit.
The further technical scheme is as follows: the first switching power supply unit comprises a first switching power supply chip U15 connected with a power adapter, the first switching power supply chip U15 is connected with a first voltage division subunit connected with one end grounded through a second switching power supply unit, the first voltage division subunit comprises a voltage division resistor R256 and a voltage division resistor R257, the voltage division resistor R256 is respectively connected with the first switching power supply chip U15 and the voltage division resistor R257, and the voltage division resistor R257 is grounded.
The further technical scheme is as follows: the second switching power supply unit is including being used for the second switching power supply chip U16 with equipment internal circuit is connected, second switching power supply chip U165 with the one end that equipment internal circuit is connected with the grounded second divider subunit of one end, the second divider subunit includes divider resistance R260 and divider resistance R261, divider resistance R260 respectively with second switching power supply chip U16 and divider resistance R261 connects, divider resistance R261 ground connection.
The further technical scheme is as follows: the comparison unit comprises a voltage comparator U360, the input end of the voltage comparator U360 is connected with the internal circuit of the equipment, and the output end of the voltage comparator U360 is connected with the electronic switch.
The further technical scheme is as follows: the electronic switch comprises a PMOS tube M1 and a PMOS tube M2; when the output end of the voltage comparator U360 outputs a high level, the gate of the PMOS transistor M1 and the gate of the PMOS transistor M2 are pulled low, and the voltage of the battery is input to the second switching power supply unit and then input to the device internal circuit; when the output end of the voltage comparator U360 outputs a low level, the PMOS transistor M1 and the PMOS transistor M2 are cut off.
The further technical scheme is as follows: a triode Q35 is connected between the PMOS tube M1 and the voltage comparator U360, and a triode Q40 is connected between the PMOS tube M2 and the voltage comparator U360.
The further technical scheme is as follows: the mechanical switch includes a mechanical switch button J14.
The further technical scheme is as follows: the battery access state detection device further comprises a state indication unit, wherein the state indication unit is used for indicating the access state of the battery.
In addition, the technical problem to be solved by the present invention is to provide an operating method of a battery low voltage automatic shutdown circuit, including:
when the battery supplies power to the internal circuit of the equipment through the electronic switch, the voltage of the battery is reduced, so that the voltage of the internal circuit of the input equipment is reduced, the comparison unit stops working, a low level signal is output, and the electronic switch is switched off;
when the equipment is plugged in a power adapter and the switch is closed, the internal circuit of the equipment is activated and electrified again, and the comparison unit judges whether the voltage of the internal circuit of the input equipment meets the requirement; when the battery power is reduced to cause the internal power supply voltage of the equipment to be unstable or lower than the comparison voltage threshold value of the comparison unit, the comparison unit outputs low level, and the electronic switch is turned off.
Compared with the prior art, the invention has the beneficial effects that: the invention uses the comparing unit, the electronic switch and the timing exciting unit, when the battery supplies power to the internal circuit of the device, the comparing unit collects the voltage of the internal circuit of the input device in real time, namely the output voltage of the battery, when the output voltage of the battery belongs to the low voltage state, the level signal output by the comparing unit turns off the electronic switch, when the switch in the timing exciting unit is pressed down or the power adapter is plugged in to electrify the internal circuit of the device again, the timing exciting unit transmits the voltage of the battery to the electronic switch to excite the comparing unit, and the comparing unit judges that the voltage of the internal circuit of the input device meets the requirement to drive the electronic switch to be turned on, thus avoiding the trouble that the traditional battery turn-off circuit needs complicated resistance value calculation, needing no manual setting of the turn-off voltage value, automatically turning off the device according to the stable state of the system voltage, under the condition of using the electric quantity of the battery to the utmost extent, the stability of the power supply in the detection equipment automatically judges whether the battery circuit needs to be cut off, and after the battery is cut off, the electric quantity of the battery is not consumed any more, so that the detection equipment has the advantages of simple design, low cost, low shutdown current and maximized battery endurance time.
The invention is further described below with reference to the accompanying drawings and specific embodiments.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
Fig. 1 is a schematic block diagram of a battery low-voltage automatic shutdown circuit according to an embodiment of the present invention;
fig. 2 is a schematic circuit diagram of a first switching power supply unit according to an embodiment of the present invention;
fig. 3 is a schematic circuit diagram of a second switching power supply unit according to an embodiment of the present invention;
FIG. 4 is a schematic diagram of a specific circuit of a comparing unit according to an embodiment of the present invention;
fig. 5 is a schematic circuit diagram of an electronic switch according to an embodiment of the present invention;
FIG. 6 is a schematic diagram of a specific circuit of a mechanical switch according to an embodiment of the present invention;
FIG. 7 is a schematic diagram of a detailed circuit of a status indication unit according to an embodiment of the present invention;
fig. 8 is a schematic circuit diagram of an embodiment of an electric power indicating unit;
the labels in the figures illustrate:
10. a comparison unit; 20. an electronic switch; 30. a timing excitation unit; 40. a first switching power supply unit; 50. a second switching power supply unit.
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 some, not all, embodiments of the present invention. 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.
It will be understood that the terms "comprises" and/or "comprising," when used in this specification and the appended claims, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
It is also to be understood that the terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in the specification of the present invention and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.
It should be further understood that the term "and/or" as used in this specification and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.
Referring to fig. 1, fig. 1 is a schematic block diagram of a battery low voltage automatic cut-off circuit according to an embodiment of the present invention, which can be applied to devices such as a wireless router, an MIFI, a wireless mouse keyboard, an intercom, a wireless headset, and the like, to implement low voltage automatic cut-off when a battery is powered on.
Referring to fig. 1, the above-mentioned battery low voltage automatic shutdown circuit includes: a comparison unit 10, an electronic switch 20, and a timing excitation unit 30; a mechanical switch is arranged in the timing excitation unit 30; the electronic switch 20, the mechanical switch and the timing excitation unit 30 are respectively connected with a battery, wherein the comparison unit 10 is used for acquiring the power supply voltage of an internal circuit of the equipment, and comparing the power supply voltage to output a level signal; an electronic switch 20 for switching off or on according to the level signal; the timing excitation unit 30 is used for transmitting the battery voltage to the electronic switch 20 when the equipment is plugged in a power adapter and the mechanical switch is closed, the circuit does not need to calculate the state of charge of the battery, when the battery power is reduced to cause the internal power supply voltage of the equipment to be unstable or lower than the comparison voltage threshold value of the comparison unit, the comparison unit outputs low level, and the electronic switch 20 is turned off.
When the device is outdoors and the like without power supplied by an adapter, the battery end VBAT is connected with the battery, at the moment, the internal circuit of the device is powered by the battery end VBAT through the electronic switch 20, when the VBAT voltage is continuously reduced to reduce 3.3V, and the comparison unit 10 does not work, the level signal CHARGE _ EN output by the comparison unit 10 does not keep high level, but outputs low level signal, the electronic switch 20 is turned off, at the moment, the voltage of VSYS and 3.3V in FIG. 1 is 0V, until the power adapter is plugged in and the mechanical switch in the timing excitation unit 30 is turned on again, the VSYS and 3.3V are powered on again, the comparison unit 10 judges whether high level is output, and when the high level signal is output, the switch unit is kept on.
Referring to fig. 1, the battery low voltage automatic shutdown circuit further includes a first switching power supply unit 40 and a second switching power supply unit 50, the first switching power supply unit is connected to the second switching power supply, and one end of the electronic switch 20 is connected between the first switching power supply unit 40 and the second switching power supply unit 50.
Specifically, VDD _12V _ IN fig. 1 is an external power adapter power supply terminal, that is, a port connected to a power adapter, and when the device is used indoors, power can be supplied by the power adapter, and the internal circuit of the device is powered by the VDD _12V _ IN through the first switching power supply unit 40 and the second switching power supply unit 50, which steps down to 3.3V.
Therefore, the circuit of the embodiment can avoid the trouble that the traditional battery turn-off circuit needs complicated resistance value calculation, the shutdown voltage value does not need to be set artificially, the circuit automatically shuts down according to the stable state of the system voltage, under the condition that the battery electric quantity is used to the maximum extent, the stability of the internal system power supply of the detection equipment automatically judges whether the battery circuit needs to be cut off, after the battery is cut off, the electric quantity of the battery is not consumed, the theoretical 0mA battery cut-off current is reached, and the battery turn-off circuit has the advantages of simple design, low cost, low shutdown current and maximized battery endurance time.
In an embodiment, referring to fig. 2, the first switching power supply unit 40 includes a first switching power supply chip U15 for connecting with a power adapter, one end of the first switching power supply chip U15 connected with the second switching power supply unit 50 is connected with a first voltage dividing subunit with one end grounded, the first voltage dividing subunit includes a voltage dividing resistor R256 and a voltage dividing resistor R257, the voltage dividing resistor R256 is respectively connected with the first switching power supply chip U15 and the voltage dividing resistor R257, and the voltage dividing resistor R257 is grounded for dynamically adjusting an output voltage.
IN fig. 2, VDD _12V _ IN is an external power input by the power adapter, and a voltage is generated by the first switching power supply chip U15: VPOW, i.e. VSYS, is the port to which the switching unit is connected.
The voltage input by the power adapter is combined with the first voltage division subunit through the first switching power supply chip U15, so that the voltage reduction operation of the input voltage is realized.
In an embodiment, referring to fig. 3, the second switching power supply unit 50 includes a second switching power supply chip U16 for connecting to an internal circuit of the device, one end of the second switching power supply chip U165 connected to the internal circuit of the device is connected to a second voltage dividing subunit with one end grounded, the second voltage dividing subunit includes a voltage dividing resistor R260 and a voltage dividing resistor R261, the voltage dividing resistor R260 is respectively connected to the second switching power supply chip U16 and the voltage dividing resistor R261, and the voltage dividing resistor R261 is grounded for dynamically adjusting a stable 3.3V output voltage.
The voltage output by the first switching power supply unit 40 is combined with the second voltage division subunit through the second switching power supply chip U16, so as to realize the voltage reduction operation of the voltage output by the first switching power supply unit 40, so as to achieve 3.3V, and supply the voltage to the internal circuit of the device.
In an embodiment, referring to fig. 4, the comparing unit 10 includes a voltage comparator U360, an input terminal of the voltage comparator U360 is connected to the internal circuit of the device, and an output terminal of the voltage comparator U360 is connected to the electronic switch 20.
The input end of the voltage comparator U360 collects the voltage input to the internal circuit of the device through the sampling resistor R2454, the output end of the voltage comparator U360 is connected with the electronic switch 20, a battery is further connected between the voltage comparator U360 and the electronic switch 20 to realize the connection between the battery and the electronic switch 20, and the battery is sequentially connected to the output end of the voltage comparator U360 through the capacitor C638 and the diode D42 to be connected with the electronic switch 20.
Specifically, the SGM803-SXN3L is used as a voltage comparator, when the internal circuit of the device is under-voltage due to the reduction of the battery voltage, the under-voltage reaches 2.93V, and the SGM803-SXN3L outputs a low level to the CHARGE _ EN network to turn off the electronic switch 20, thereby realizing the automatic cut-off of the battery low voltage.
In an embodiment, referring to fig. 5, the electronic switch 20 includes a PMOS transistor M1 and a PMOS transistor M2; when the output end of the voltage comparator U360 outputs a high level, the gate of the PMOS transistor M1 and the gate of the PMOS transistor M2 are pulled low, and the voltage of the battery is input to the second switching power supply unit 50 and then input to the internal circuit of the device; when the output terminal of the voltage comparator U360 outputs a low level, the PMOS transistor M1 and the PMOS transistor M2 are turned off.
Specifically, a transistor Q35 is connected between the PMOS transistor M1 and the voltage comparator U360, and a transistor Q40 is connected between the PMOS transistor M2 and the voltage comparator U360.
In this embodiment, the electronic switch 20 is mainly composed of a MOS electronic switch, the electronic switch 20 receives the control signal CHARGE _ EN from the comparing unit 10, that is, the level signal output by the comparing unit 10, when CHARGE _ EN is at a low level, the gates of the PMOS transistors M1 and M2 are at a high level, so that the PMOS transistors M1 and M2 are not conductive, and when CHARGE _ EN is at a high level, the transistors Q35 and Q40 pull down the gates of the PMOS transistors M1 and M2, so that the PMOS transistors M1 and M2 are conductive, and further the channel between the battery and the first switching power supply unit 40 and the second switching power supply unit 50 is conductive to conduct the battery voltage to VSYS to supply power to the internal circuit of the device; when the battery of the equipment is just charged and needs to be powered on from the battery, the mechanical switch needs to be pressed down again.
In one embodiment, referring to fig. 6, the mechanical switch includes a mechanical switch button J14.
When the switch button J14 is in the pop-up state, pins 1 and 2 of the switch button J14 are connected in pairs, pins 4 and 5 of the switch button are connected in pairs, pin 4 of the switch button J14 is connected to the 0R resistor to the ground, and the function is to make the capacitance on the internal circuit side: i.e., the VBAT terminal of capacitor C638 in fig. 4 discharges to 0V as soon as possible, in preparation for the next generation of the fire signal to CHARGE _ EN, when the switch button J14 is pressed, pins 2 and 3 of the switch button J14 are connected IN pairs, pins 5 and 6 of the switch button J14 are connected IN pairs, the VBAT _ IN end is the battery side, pins 5 and 6 of the switch button J14 are connected at the instant, because the capacitor voltage cannot suddenly change, the a terminal of the diode D42 IN fig. 4 is immediately pulled up to VBAT, that is, the battery voltage VBAT _ IN, at this time, CHARGE _ EN is pulled up, the electronic switch 20 is turned on, VSYS is powered on to supply power to the internal circuit of the device, the voltage comparator U360 detects whether the voltage of 3.3V, that is, the voltage of the internal circuit of the input device is stable and is lower than 2.93V, if the voltage of the internal circuit of the input device is stable and is not lower than 2.93V, the voltage comparator U360 outputs a high level, CHARGE _ EN is pulled up, and the electronic switch 20 is IN a conducting state; if the voltage of the internal circuit of the input device is unstable and is lower than 2.93V, the voltage comparator U360 outputs a low level, and the CHARGE _ EN standby capacitor C638 discharges to the low level through the resistor R743, so that the voltage input to the electronic switch 20 is at the low level, and the electronic switch 20 is restored to the off state.
In an embodiment, referring to fig. 7, the automatic battery low-voltage cutoff circuit further includes a status indication unit, and the status indication unit is configured to indicate an access status of the battery.
The status indication unit includes a light emitting diode DS16 to indicate whether the battery is connected or not by whether the light emitting diode DS16 is on or off.
In an embodiment, referring to fig. 8, the above-mentioned battery low voltage automatic shutdown circuit further includes a battery charging unit, where the battery charging unit is configured to automatically charge the battery, and specifically, the charging unit includes a chip U359, and the battery charging chip U359 is connected to the battery to automatically charge the battery and display the battery access or charging status.
The voltage low-voltage automatic cut-off circuit comprises a comparison unit 10, an electronic switch 20 and a timing excitation unit 30, wherein when the internal circuit of the device is powered by a battery, the comparison unit 10 collects the voltage of the internal circuit of the input device, namely the output voltage of the battery in real time, when the output voltage of the battery belongs to a low-voltage state, a level signal output by the comparison unit 10 enables the electronic switch 20 to be turned off, when a switch in the timing excitation unit 30 is pressed down and the internal circuit of the device is powered on again by inserting a power adapter, the timing excitation unit 30 transmits the voltage of the battery to the electronic switch 20, the comparison unit 10 is excited, the comparison unit 10 judges that the voltage of the internal circuit of the input device meets the requirement, the electronic switch 20 is driven to be turned on, the trouble that the traditional battery turn-off circuit needs complicated resistance value calculation is avoided, the shutdown voltage value does not need to be set manually, and the automatic shutdown can be automatically carried out according to the stable state of the system voltage, under the condition of using the electric quantity of the battery to the maximum extent, the stability of the power supply in the detection equipment automatically judges whether the battery circuit needs to be cut off, and after the battery is cut off, the electric quantity of the battery is not consumed any more, so that the battery power supply has the advantages of being concise in design, low in cost, low in shutdown current and capable of maximizing battery endurance time.
In one embodiment, there is also provided a method for operating a battery low voltage automatic shutdown circuit, including:
when the battery supplies power to the internal circuit of the device through the electronic switch 20, the voltage of the battery is reduced, so that the voltage of the internal circuit of the device is reduced, the comparison unit 10 stops working, a low-level signal is output, and the electronic switch 20 is turned off;
when the device is plugged in a power adapter and the switch is closed, the internal circuit of the device is activated and powered on again, and the comparison unit 10 judges whether the voltage of the internal circuit of the input device meets the requirement; the circuit does not need to calculate the state of charge of the battery, and when the battery power level decreases to cause the internal power supply voltage of the device to be unstable or to be lower than the comparison voltage threshold of the comparison unit, the comparison unit outputs a low level, and the electronic switch 20 is turned off.
It should be noted that, as can be clearly understood by those skilled in the art, the specific implementation process of the working method of the battery low-voltage automatic cutout circuit may refer to the corresponding description in the foregoing embodiment of the battery low-voltage automatic cutout circuit, and for convenience and brevity of description, no further description is provided herein.
While the invention has been described with reference to specific embodiments, the invention is not limited thereto, and various equivalent modifications and substitutions can be easily made by those skilled in the art within the technical scope of the invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (10)
1. A battery low voltage automatic cutout circuit characterized by comprising: the device comprises a comparison unit, an electronic switch and a timing excitation unit; a mechanical switch is arranged in the timing excitation unit; the electronic switch, the mechanical switch and the timing excitation unit are respectively connected with a battery, wherein the comparison unit is used for acquiring the power supply voltage of an internal circuit of the equipment and comparing the power supply voltage to output a level signal; the electronic switch is used for carrying out cutoff or conduction according to the level signal; the timing excitation unit is used for transmitting the battery voltage to the electronic switch when the equipment is plugged in the power adapter and the mechanical switch is closed, and when the battery power is reduced to cause the internal power supply voltage of the equipment to be unstable or lower than the comparison voltage threshold value of the comparison unit, the comparison unit outputs low level, and the electronic switch is turned off.
2. The battery low-voltage automatic cutout circuit of claim 1, characterized by further comprising a first switching power supply unit and a second switching power supply unit, wherein the first switching power supply unit is connected with the second switching power supply, and one end of the electronic switch is connected between the first switching power supply unit and the second switching power supply unit.
3. The battery low voltage automatic cutout circuit of claim 2, characterized in that, the first switching power supply unit comprises a first switching power supply chip U15 for connecting with a power adapter, one end of the first switching power supply chip U15 connected with the second switching power supply unit is connected with a first voltage dividing subunit with one end grounded, the first voltage dividing subunit comprises a voltage dividing resistor R256 and a voltage dividing resistor R257, the voltage dividing resistor R256 is respectively connected with the first switching power supply chip U15 and the voltage dividing resistor R257, and the voltage dividing resistor R257 is grounded.
4. The battery low-voltage automatic cutout circuit of claim 3, characterized in that said second switching power supply unit comprises a second switching power supply chip U16 for connecting with the internal circuit of the device, one end of said second switching power supply chip U165 connected with the internal circuit of the device is connected with a second voltage-dividing subunit with one end grounded, said second voltage-dividing subunit comprises a voltage-dividing resistor R260 and a voltage-dividing resistor R261, said voltage-dividing resistor R260 is respectively connected with said second switching power supply chip U16 and said voltage-dividing resistor R261, and said voltage-dividing resistor R261 is grounded.
5. The automatic cut-off circuit for low voltage of battery as claimed in claim 4, wherein said comparing unit comprises a voltage comparator U360, an input terminal of said voltage comparator U360 is connected to said internal circuit of the device, and an output terminal of said voltage comparator U360 is connected to said electronic switch.
6. The automatic low-voltage battery shutoff circuit according to claim 5, wherein the electronic switch includes a PMOS transistor M1 and a PMOS transistor M2; when the output end of the voltage comparator U360 outputs a high level, the gate of the PMOS transistor M1 and the gate of the PMOS transistor M2 are pulled low, and the voltage of the battery is input to the second switching power supply unit and then input to the device internal circuit; when the output end of the voltage comparator U360 outputs a low level, the PMOS transistor M1 and the PMOS transistor M2 are cut off.
7. The automatic cut-off circuit for low voltage of battery as claimed in claim 6, wherein a transistor Q35 is connected between the PMOS transistor M1 and the voltage comparator U360, and a transistor Q40 is connected between the PMOS transistor M2 and the voltage comparator U360.
8. The battery low voltage automatic cutout circuit of claim 1 wherein said mechanical switch comprises a mechanical switch button J14.
9. The automatic cut-off circuit for low voltage of battery as claimed in claim 1, further comprising a status indication unit for indicating the access status of battery.
10. The working method of the battery low-voltage automatic cut-off circuit is characterized by comprising the following steps:
when the battery supplies power to the internal circuit of the equipment through the electronic switch, the voltage of the battery is reduced, so that the voltage of the internal circuit of the input equipment is reduced, the comparison unit stops working, a low level signal is output, and the electronic switch is switched off;
when the equipment is plugged in a power adapter and the switch is closed, the internal circuit of the equipment is activated and electrified again, and the comparison unit judges whether the voltage of the internal circuit of the input equipment meets the requirement; when the battery power is reduced to cause the internal power supply voltage of the equipment to be unstable or lower than the comparison voltage threshold value of the comparison unit, the comparison unit outputs low level, and the electronic switch is turned off.
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| CN202110984845.9A CN113676166B (en) | 2021-08-24 | 2021-08-24 | Battery low-voltage automatic cut-off circuit and working method thereof |
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| CN202110984845.9A CN113676166B (en) | 2021-08-24 | 2021-08-24 | Battery low-voltage automatic cut-off circuit and working method thereof |
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Cited By (1)
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| CN114336531A (en) * | 2022-03-09 | 2022-04-12 | 荣耀终端有限公司 | Leakage protection circuit and electronic device |
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| CN108923376A (en) * | 2018-08-22 | 2018-11-30 | 中国科学院西安光学精密机械研究所 | A kind of overcurrent turn-off function guard method of self recovery and circuit |
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| US5073837A (en) * | 1989-08-10 | 1991-12-17 | Samsung Electronics Co., Ltd. | Low voltage protection circuit |
| US5683827A (en) * | 1995-11-20 | 1997-11-04 | Mobius Green Energy, Inc. | Protective device for protecting individual battery cells in a batterypack from damages and hazards caused by reverse polarity during discharge cycles |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114336531A (en) * | 2022-03-09 | 2022-04-12 | 荣耀终端有限公司 | Leakage protection circuit and electronic device |
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| Publication number | Publication date |
|---|---|
| CN113676166B (en) | 2022-06-24 |
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