CN110829386A - Battery protection circuit and charging power switch control signal generation circuit thereof - Google Patents

Battery protection circuit and charging power switch control signal generation circuit thereof Download PDF

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Publication number
CN110829386A
CN110829386A CN201911263428.4A CN201911263428A CN110829386A CN 110829386 A CN110829386 A CN 110829386A CN 201911263428 A CN201911263428 A CN 201911263428A CN 110829386 A CN110829386 A CN 110829386A
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China
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charging
battery
mos tube
detection
circuit
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CN201911263428.4A
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Chinese (zh)
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王钊
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Nanjing Sino Microelectronics Co Ltd
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Nanjing Sino Microelectronics Co Ltd
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
    • H02H7/18—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for batteries; for accumulators
    • 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

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Charge And Discharge Circuits For Batteries Or The Like (AREA)

Abstract

The invention provides a battery protection circuit and a charging power switch control signal generating circuit thereof, wherein the charging power switch control signal generating circuit comprises: a controller for detecting whether charging of the battery is permitted; the first MOS tube is connected with the first detection end at a first connection end, is connected with the charging control end at a second connection end, and is connected with the output end of the controller at a control end; the first resistor and the second resistor are sequentially connected in series between the charging control end and the second detection end; the first connecting end of the second MOS tube is connected with the charging control end, the second connecting end of the second MOS tube is connected with a connecting node between the first resistor and the second resistor, and the control end of the second MOS tube is connected with the output end of the charging overcurrent detection circuit; and the charging overcurrent detection circuit is used for detecting whether the battery is over-current in charging. Compared with the prior art, the invention can accelerate the speed of pulling down the control signal of the charging power switch when the charging is in an overcurrent state, thereby leading the charging power switch to be turned off in time.

Description

Battery protection circuit and charging power switch control signal generation circuit thereof
[ technical field ] A method for producing a semiconductor device
The invention relates to the field of circuit design, in particular to a battery protection circuit and a charging power switch control signal generation circuit thereof.
[ background of the invention ]
The battery protection Circuit is typically mounted in a battery, for example, a small Printed Circuit Board (PCB) inside a battery of a mobile phone, on which the battery protection Circuit is mounted. The battery protection circuit is used for controlling charging and discharging of the battery, and the basic functions of the battery protection circuit comprise overvoltage charging protection, overvoltage discharging protection, discharging overcurrent protection, charging overcurrent protection and short-circuit protection.
Fig. 1 is a schematic circuit diagram of a battery protection system in the prior art. The battery protection system comprises a battery protection circuit (or called battery protection chip), a charging power switch (or charging power tube) MN2, a discharging power switch (or discharging power tube) MN1, a resistor R and a capacitor C. The battery protection circuit needs to output a charging power switch control signal CO and a discharging power switch control signal DO to control the charging and discharging of the battery cell BT 1.
Please refer to fig. 2, which is a circuit (or a driving circuit) for generating a charging power switch control signal CO in the prior art, specifically refer to the chinese patent application: CN 201210484658.5. For the process without the high-voltage isolation NMOS, the circuit structure shown in FIG. 2 is adopted, so that the CO signal can be well driven; for a battery protection circuit without a charging overcurrent protection circuit, the circuit structure shown in fig. 2 is adopted, and the battery protection circuit can work well. Firstly, when the battery protection circuit needs integrated charging overcurrent protection, the circuit shown in fig. 2 causes the CO signal to fall for too long time, which may cause the charging power tube (or the charging power switch) to be protected too slowly in the charging overcurrent state, thereby causing the charging power tube to be damaged; second, when the circuit is in a normal unprotected state, the resistor R1 will consume current, resulting in a larger normal operating current.
Therefore, there is a need for an improved solution to overcome the above problems.
[ summary of the invention ]
One of the objectives of the present invention is to provide a battery protection circuit and a charging power switch control signal generating circuit thereof, wherein the battery protection circuit integrates a charging overcurrent protection function, and when a charging overcurrent state is detected, the charging power switch control signal generating circuit can increase the speed of pulling down a charging power switch control signal CO, so that a charging power switch is turned off in time, and the charging overcurrent protection speed of the battery protection circuit is increased.
According to one aspect of the invention, the invention provides a battery protection circuit and a charging power switch control signal generation circuit thereof.
The charging power switch control signal generating circuit includes: the controller is used for detecting whether the battery is allowed to be charged or not and outputting a corresponding first control signal through an output end of the controller; the first MOS tube is connected with the first detection end at a first connection end, is connected with the charging control end at a second connection end, and is connected with the output end of the controller at a control end; the first resistor and the second resistor are sequentially connected in series between the charging control end and the second detection end; a first connecting end of the second MOS tube is connected with a charging control end, a second connecting end of the second MOS tube is connected with a connecting node between the first resistor and the second resistor, and a control end of the second MOS tube is connected with an output end of the charging overcurrent detection circuit; and the charging overcurrent detection circuit is used for detecting whether the battery is charged and overcurrent or not and outputting a corresponding second control signal through an output end of the charging overcurrent detection circuit.
Further, when the fact that the battery is allowed to be charged is detected, the controller controls the first MOS tube to be conducted through the output end of the controller; when the situation that the battery is forbidden to be charged is detected, the controller controls the first MOS tube to be turned off through the output end of the controller; when the charging overcurrent detection circuit detects that the battery is not in overcurrent during charging, the charging overcurrent detection circuit controls the second MOS tube to be cut off through the output end of the charging overcurrent detection circuit; when the charging overcurrent of the battery is detected, the charging overcurrent detection circuit controls the conduction of the second MOS tube through the output end of the charging overcurrent detection circuit.
Further, the first MOS transistor and the second MOS transistor are both PMOS transistors, and the first connection end, the second connection end and the control end of the first MOS transistor and the second MOS transistor are respectively a source electrode, a drain electrode and a gate electrode of the PMOS transistor; and the substrate ends of the first MOS tube and the second MOS tube are connected with the first detection end.
Furthermore, a first power end of the charging overcurrent detection circuit is connected with the first detection end, a second power end of the charging overcurrent detection circuit is connected with the third detection end, and when the charging overcurrent of the battery is detected, the voltage of a first control signal output by the output end of the charging overcurrent detection circuit to the control end of the second MOS transistor is equal to the voltage of the third detection end G, so that the second MOS transistor is conducted.
Further, the first detection end is a connection end of the battery protection circuit and the positive electrode of the battery core; the second detection end is a connection end for connecting the battery protection circuit with the negative electrode of the battery; the third detection end is a connection end for connecting the battery protection circuit and the cathode of the battery core, and the first resistance is more than or equal to 106Ohm; the second resistance is less than or equal to 500 ohms.
The battery protection circuit comprises a second detection end connected with the negative electrode of the battery, a third detection end connected with the negative electrode of the battery, a first detection end connected with the positive electrode of the battery, a discharge control end connected with the control end of the discharge power switch and a charge control end connected with the control end of the charge power switch, wherein the discharge power switch and the charge power switch are connected between the third detection end and the second detection end. The battery protection circuit further comprises a charging power switch control signal generation circuit. The charging power switch control signal generating circuit includes: the controller is used for detecting whether the battery is allowed to be charged or not and outputting a corresponding first control signal through an output end of the controller; the first MOS tube is connected with the first detection end at a first connection end, is connected with the charging control end at a second connection end, and is connected with the output end of the controller at a control end; the first resistor and the second resistor are sequentially connected in series between the charging control end and the second detection end; a first connecting end of the second MOS tube is connected with a charging control end, a second connecting end of the second MOS tube is connected with a connecting node between the first resistor and the second resistor, and a control end of the second MOS tube is connected with an output end of the charging overcurrent detection circuit; and the charging overcurrent detection circuit is used for detecting whether the battery is charged and overcurrent or not and outputting a corresponding second control signal through an output end of the charging overcurrent detection circuit.
According to another aspect of the present invention, another battery protection circuit and a charging power switch control signal generation circuit thereof are provided.
The charging power switch control signal generating circuit includes: the controller is used for detecting whether the battery is allowed to be charged or not and outputting a corresponding first control signal through an output end of the controller; the first MOS tube is connected with the first detection end V at a first connection end, is connected with the charging control end at a second connection end, and is connected with the output end of the controller at a control end; the first resistor, the third resistor and the second resistor are sequentially connected in series between the charging control end and the second detection end; a first connecting end of the second MOS tube is connected with the charging control end, and a second connecting end of the second MOS tube is connected with a connecting node between the first resistor and the third resistor; the first connection end of the third MOS tube is connected with the first detection end, the second connection end of the third MOS tube is connected with the control end of the second MOS tube, and the control end of the third MOS tube is connected with the output end of the charging overcurrent detection circuit; and the charging overcurrent detection circuit is used for detecting whether the battery is charged and overcurrent and outputting a corresponding third control signal through the output end of the charging overcurrent detection circuit.
Further, when the fact that the battery is allowed to be charged is detected, the controller controls the first MOS tube to be conducted through the output end of the controller; when the situation that the battery is forbidden to be charged is detected, the controller controls the first MOS tube to be turned off through the output end of the controller; when the charging overcurrent detection circuit detects that the battery is not charged and overcurrent, the charging overcurrent detection circuit controls the conduction of the third MOS tube through the output end of the charging overcurrent detection circuit, and the conduction of the third MOS tube enables the second MOS tube to be cut off; when the charging overcurrent of the battery is detected, the charging overcurrent detection circuit controls the third MOS tube to be switched off through the output end of the charging overcurrent detection circuit, and the third MOS tube is switched off to enable the second MOS tube to be switched on.
Further, the first MOS transistor, the second MOS transistor and the third MOS transistor are all PMOS transistors, and the first connection end, the second connection end and the control end of the first MOS transistor, the second MOS transistor and the third MOS transistor are respectively a source electrode, a drain electrode and a gate electrode of the PMOS transistor; and the substrate ends of the first MOS tube, the second MOS tube and the third MOS tube are all connected with the first detection end.
Further, a first power end of the charging overcurrent detection circuit is connected with the first detection end, a second power end of the charging overcurrent detection circuit is connected with the third detection end, when the charging overcurrent detection circuit detects that the battery is charged and overcurrent, the charging overcurrent detection circuit controls the third MOS tube to be turned off, and at the moment, the voltage of a control end of the second MOS tube is smaller than that of the second detection end.
Further, the first detection end is a connection end of the battery protection circuit and the positive electrode of the battery core; the second detection end is a connection end for connecting the battery protection circuit with the negative electrode of the battery; the third detection end is a connection end for connecting the battery protection circuit and the cathode of the battery core, and the first resistance is more than or equal to 106Ohm; the second resistance is less than or equal to 500 ohms.
The battery protection circuit comprises a second detection end connected with the negative electrode of the battery, a third detection end connected with the negative electrode of the battery, a first detection end connected with the positive electrode of the battery, a discharge control end connected with the control end of the discharge power switch and a charge control end connected with the control end of the charge power switch, wherein the discharge power switch and the charge power switch are connected between the third detection end and the second detection end. The battery protection circuit further comprises a charging power switch control signal generation circuit. The charging power switch control signal generating circuit includes: the controller is used for detecting whether the battery is allowed to be charged or not and outputting a corresponding first control signal through an output end of the controller; the first MOS tube is connected with the first detection end V at a first connection end, is connected with the charging control end at a second connection end, and is connected with the output end of the controller at a control end; the first resistor, the third resistor and the second resistor are sequentially connected in series between the charging control end and the second detection end; a first connecting end of the second MOS tube is connected with the charging control end, and a second connecting end of the second MOS tube is connected with a connecting node between the first resistor and the third resistor; the first connection end of the third MOS tube is connected with the first detection end, the second connection end of the third MOS tube is connected with the control end of the second MOS tube, and the control end of the third MOS tube is connected with the output end of the charging overcurrent detection circuit; and the charging overcurrent detection circuit is used for detecting whether the battery is charged and overcurrent and outputting a corresponding third control signal through the output end of the charging overcurrent detection circuit.
Compared with the prior art, the charging overcurrent protection circuit is additionally provided with the charging overcurrent detection circuit and the MOS tube MP2 which is connected with the resistor R1 in parallel, when the charging overcurrent detection circuit detects charging overcurrent, the MOS tube MP2 is controlled to be switched on, so that the speed of pulling down the control signal CO of the charging power switch is increased, the charging power switch MN2 is timely switched off, and the charging overcurrent protection speed of the battery protection circuit is increased.
[ description of the 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 will be briefly introduced below, and it is obvious that the drawings in the following description are only 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 inventive exercise. Wherein:
fig. 1 is a schematic circuit diagram of a battery protection system in the prior art;
fig. 2 is a circuit for generating a charging power switch control signal CO according to the prior art;
FIG. 3 is a circuit diagram of a charging power switch control signal generating circuit in a battery protection circuit according to an embodiment of the present invention;
fig. 4 is a circuit diagram of a charging power switch control signal generating circuit in the battery protection circuit according to another embodiment of the present invention.
[ detailed description ] embodiments
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.
Reference herein to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic may be included in at least one implementation of the invention. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Unless otherwise specified, the terms connected, and connected as used herein mean electrically connected, directly or indirectly.
Referring to fig. 1, the battery protection system of the present invention includes a battery cell BT1, a resistor R, a capacitor C, a battery protection circuit (or battery protection chip) 110, a charging power switch 120, and a discharging power switch 130. The resistor R and the capacitor C are connected in series between the positive electrode B + and the negative electrode B-of the battery cell BT1, the discharging power switch MN1 and the charging power switch MN2 are connected in series between the negative electrode B-of the battery cell and the negative electrode P-of the battery, and the positive electrode B + of the battery cell BT1 is directly connected with the positive electrode P + of the battery.
The charging power switch 120 includes a charging switch tube and a diode (not shown) parasitic in the charging switch tube. In one embodiment of the present invention, the charge switch transistor is an NMOS (N-channel Metal oxide semiconductor) field effect transistor MN 2. The discharge power switch 130 includes a discharge switch transistor, which is an NMOS field effect transistor MN1 in one embodiment of the present invention, and a diode (not shown) parasitic in the discharge switch transistor. The drain electrode of the NMOS transistor MN1 is connected with the drain electrode of the NMOS transistor MN2, the source electrode of the NMOS transistor MN1 is connected with the cathode B-of the battery cell, and the source electrode of the NMOS transistor MN2 is connected with the cathode P-of the battery.
The battery protection circuit 110 includes three detection terminals (or called connection terminals) and two control terminals, the three detection terminals are a battery cell positive electrode B + a detection terminal VDD, a battery cell negative electrode B-a detection terminal G and a battery negative electrode P-a detection terminal VM, and the two control terminals are a charging control terminal CO and a discharging control terminal DO, respectively. The detection end VDD is connected between the resistor R and the capacitor C, the detection end G is connected to the negative electrode B-of the battery cell, the detection end VM is connected to the negative electrode P-of the battery, the charging control end CO is connected to the control end of the charging power switch 120 (i.e., the gate of the NMOS transistor MN 2), and the discharging control end DO is connected to the control end of the discharging power switch 130 (i.e., the gate of the NMOS transistor MN 1).
The battery protection circuit 110 can realize charge protection and discharge protection of the battery cell BT1 by controlling the on and off of the NMOS transistors MN1 and MN 2. In a normal state, the battery protection circuit 110 controls the NMOS transistors MN1 and MN2 to be turned on simultaneously, and at this time, the battery protection circuit can be charged or discharged. When charging is abnormal, the battery protection circuit 110 controls the NMOS transistor MN2 to turn off, thereby cutting off the charging loop, but still discharging. When abnormal discharging occurs, the battery protection circuit 110 controls the NMOS transistor MN1 to be turned off, thereby cutting off the discharging loop, but charging is still possible.
Fig. 3 is a schematic circuit diagram of a charging power switch control signal generating circuit in a battery protection circuit according to an embodiment of the invention.
As shown in fig. 3, the charging power switch control signal generating circuit in the battery protection circuit of the present invention includes a controller 310, a first MOS transistor MP1, a second MOS transistor MP2, a first resistor R1, a second resistor R2, and a charging overcurrent detecting circuit 320.
The controller 310 is configured to detect whether charging of the battery is allowed or not, and output a corresponding first control signal through an output terminal thereof. The first connection end of the first MOS transistor MP1 is connected to the first detection end VDD, the second connection end thereof is connected to the charging control end CO, and the control end thereof is connected to the output end of the controller 310. The first resistor R1 and the second resistor 2 are sequentially connected in series between the charging control terminal CO and the second detection terminal VM. A first connection end of the second MOS transistor MP2 is connected to the charging control end CO, a second connection end thereof is connected to a connection node O1 between the first resistor R1 and the second resistor R2, and a control end thereof is connected to an output end of the charging overcurrent detection circuit 320. The charging overcurrent detecting circuit 320 is configured to detect whether the battery is charging overcurrent, and output a corresponding second control signal ECIB through an output terminal thereof.
In the specific embodiment shown in fig. 3, the first MOS transistor MP1 and the second MOS transistor MP2 are both PMOS transistors (P-channel Metal Oxide Semiconductor), and the first connection end, the second connection end, and the control end of the first MOS transistor MP1 and the second MOS transistor MP2 are respectively a source, a drain, and a gate of the PMOS transistor; a first power end of the charging overcurrent detection circuit 320 is connected with a first detection end VDD, and a second power end thereof is connected with the third detection end G; the substrate ends of the first MOS transistor MP1 and the second MOS transistor MP2 are both connected with the first detection end VDD; the first detection end VDD is a connection end of the battery protection circuit and the positive electrode of the battery core; the second detection end VM is a connecting end of the battery protection circuit connected with the negative electrode of the battery; and the third detection end G is a connection end for connecting the battery protection circuit and the cathode of the battery core.
The operation principle of the charging power switch control signal generating circuit in the battery protection circuit shown in fig. 3 is described in detail below with reference to fig. 1.
When it is detected that the battery is allowed to be charged, the controller 310 outputs a first logic level of a first control signal through its output terminal to control the first MOS transistor MP1 to be turned on, so that the charging control terminal CO outputs a high level, the charging power switch 120 is turned on, and the battery protection circuit 110 allows the battery to be charged. When the battery charging inhibition is detected, the controller 310 outputs a second logic level of the first control signal through its output terminal to control the first MOS transistor MP1 to turn off; at this time, the potential of the charging control terminal CO is pulled down by at least the first resistor R1 and the second resistor R2, so that the charging control terminal CO outputs a low level, the charging power switch 120 is turned off, and the battery protection circuit 110 prohibits charging the battery. Wherein the prohibiting of charging the battery includes a battery charging overvoltage and a battery charging overcurrent.
When it is detected that the charging to the battery is not over-current, the charging over-current detection circuit 320 outputs a second logic level of the second control signal ECIB through its output terminal to control the second MOS transistor MP2 to turn off. When an overcurrent is detected in the charge of the battery,the charging overcurrent detecting circuit 320 outputs the first logic level of the second control signal ECIB through its output terminal to control the second MOS transistor MP2 to be turned on. When the charging overcurrent to the battery is detected, the charging overcurrent detection circuit 320 controls the second MOS transistor MP2 to be turned on. Therefore, the resistance connected in series between the charging control terminal CO and the second detection terminal VM is equivalently reduced, so that the speed of pulling down the potential of the charging control terminal CO is increased, namely the time of the potential drop of the charging control terminal CO is reduced. Since the battery protection circuit shown in fig. 3 can increase the discharge speed, the total resistance (the first resistor R1+ the second resistor R2) can be made larger, so that the current consumption in the unprotected state can be reduced. The resistor R2 mainly plays a role of electrostatic protection, the resistance of the resistor R2 can be actually small, generally, the second resistor R2 is less than or equal to 500 ohms, for example, the second resistor R2 is equal to 200 ohms; the first resistor R1 is designed to be large, for example, the first resistor R1 is greater than or equal to 106Ohm.
It should be particularly noted that, in the specific embodiment shown in fig. 3, the first logic levels of the first control signal ECIB and the second control signal ECIB are both low levels, and the second logic levels of the first control signal ECIB and the second control signal ECIB are both high levels, where the first logic level and the second logic level are two logic states of the same control signal; the low level (i.e., the first logic level) of the second control signal ECIB is equal to the voltage of the third detection terminal G (i.e., the ground node). When the charger Adapter is inserted, the second detection terminal VM is negative voltage with respect to the third detection terminal G.
Fig. 4 is a schematic circuit diagram of a charging power switch control signal generating circuit in a battery protection circuit according to another embodiment of the present invention. Compared with fig. 3, the embodiment shown in fig. 4 adds a third MOS transistor MP3, a third resistor R3 and a fourth resistor R4.
As shown in fig. 4, the charging power switch control signal generating circuit in the battery protection circuit of the present invention includes a controller 310, a first MOS transistor MP1, a second MOS transistor MP2, a third MOS transistor MP3, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, and a charging overcurrent detecting circuit 320.
The controller 310 is configured to detect whether charging of the battery is allowed or not, and output a corresponding first control signal through an output terminal thereof. The first connection end of the first MOS transistor MP1 is connected to the first detection end VDD, the second connection end thereof is connected to the charging control end CO, and the control end thereof is connected to the output end of the controller 310. The first resistor R1, the third resistor R3 and the second resistor 2 are sequentially connected in series between the charging control end CO and the second detection end VM. A first connection end of the second MOS transistor MP2 is connected to the charging control end CO, and a second connection end thereof is connected to a connection node O2 between the first resistor R1 and the third resistor R3.
The first connection end of the third MOS transistor MP3 is connected to the first detection end VDD, the second connection end thereof is connected to the control end of the second MOS transistor MP2, and the control end thereof is connected to the output end of the charging overcurrent detection circuit 320. One end of the fourth resistor R4 is connected to the second connection terminal of the third MOS transistor MP3, and the other end thereof is connected to the connection node O3 between the third resistor R3 and the second resistor R2. The charging overcurrent detecting circuit 320 is configured to detect whether the battery is charging overcurrent, and output a corresponding third control signal ECI through an output terminal thereof.
In the specific embodiment shown in fig. 4, the first MOS transistor MP1, the second MOS transistor MP2, and the third MOS transistor MP3 are all PMOS transistors, and the first connection end, the second connection end, and the control end of the first MOS transistor MP1, the second MOS transistor MP2, and the third MOS transistor MP3 are respectively a source, a drain, and a gate of the PMOS transistor; a first power end of the charging overcurrent detection circuit 320 is connected with a first detection end VDD, and a second power end thereof is connected with the third detection end G; the substrate ends of the first MOS transistor MP1, the second MOS transistor MP2 and the third MOS transistor MP3 are all connected with the first detection end VDD; the first detection end VDD is a connection end of the battery protection circuit and the positive electrode of the battery core; the second detection end VM is a connecting end of the battery protection circuit connected with the negative electrode of the battery; and the third detection end G is a connection end for connecting the battery protection circuit and the cathode of the battery core.
The operation principle of the charging power switch control signal generating circuit in the battery protection circuit shown in fig. 4 will be described in detail below with reference to fig. 1.
When it is detected that the battery is allowed to be charged, the controller 310 outputs a first logic level of a first control signal through its output terminal to control the first MOS transistor MP1 to be turned on, so that the charging control terminal CO outputs a high level, the charging power switch 120 is turned on, and the battery protection circuit 110 allows the battery to be charged. When the battery charging inhibition is detected, the controller 310 outputs a second logic level of the first control signal through its output terminal to control the first MOS transistor MP1 to turn off; at this time, the potential of the charge control terminal CO is pulled down by at least the first resistor R1, the second resistor R2 and the third resistor R3, so that the charge control terminal CO outputs a low level, the charge power switch 120 is turned off, and the battery protection circuit 110 prohibits charging the battery. Wherein the prohibiting of charging the battery includes a battery charging overvoltage and a battery charging overcurrent.
When it is detected that the battery is not being charged in an overcurrent state, the charging overcurrent detection circuit 320 outputs the first logic level of the third control signal ECI through the output terminal thereof to control the third MOS transistor MP3 to be turned on, and at this time, the second connection terminal of the third MOS transistor MP3 outputs the second logic level of the second control signal ECIB to control the second MOS transistor MP2 to be turned off. When the charging overcurrent is detected, the charging overcurrent detection circuit 320 outputs the second logic level of the third control signal ECI through the output terminal thereof to control the third MOS transistor MP3 to turn off, and at this time, the second connection terminal of the third MOS transistor MP3 outputs the first logic level of the second control signal ECIB to control the second MOS transistor MP2 to turn on. Wherein the second control signal ECIB and the third control signal ECI are inverse signals; when the charger Adapter is inserted, the second detection terminal VM is negative voltage with respect to the third detection terminal G.
In the specific embodiment shown in fig. 4, the first logic levels of the first control signal, the second control signal ECIB and the third control signal ECI are all low; the second logic levels of the first control signal, the second control signal ECIB, and the third control signal ECI are all high levels, wherein the first logic level and the second logic level are two logic states of the same control signal.
It should be noted that the circuit shown in fig. 3 mainly increases the speed of the charging control terminal CO when the voltage of the first detection terminal VDD decreases to VG + | Vthp |, where VG is the voltage value of the third detection terminal G, and Vthp is the threshold voltage of the second MOS transistor MP 2. Because the second MOS transistor MP2 can be turned on only during this time. When the voltage of the charge control terminal CO is lower than VG + | Vthp |, the discharge is still determined by the first resistor R1, and thus is also slow. With the circuit design shown in fig. 4, when a discharging overcurrent state is detected, the third control signal ECI changes to a high level, the third MOS transistor MP3 is turned off, the fourth resistor R4 pulls down the gate of the second MOS transistor MP2 to a relatively low voltage VN (i.e., the second control signal ECIB changes to a low level, which is VN), and the voltage VN is lower than the voltage of the third detection terminal G, so that the second MOS transistor MP2 can be turned on for a longer time, and the speed of pulling down the CO potential of the charging control terminal is further increased, and therefore, fig. 4 can realize a shorter CO potential drop time of the charging control terminal than that of fig. 3.
Since the battery protection circuit shown in fig. 4 can increase the discharge speed, the total resistance (the first resistor R1+ the second resistor R2+ the third resistor R3) can be made larger, so that the current consumption in the unprotected state can be reduced. The resistor R2 mainly plays a role of electrostatic protection, the resistance of the resistor R2 can be actually small, generally, the second resistor R2 is less than or equal to 500 ohms, for example, the second resistor R2 is equal to 200 ohms; the first resistor R1 is designed to be large, for example, the first resistor R1 is greater than or equal to 106Ohm.
In the present invention, the terms "connected", "connecting", and the like mean electrical connections, and direct or indirect electrical connections unless otherwise specified.
It should be noted that those skilled in the art can make modifications to the embodiments of the present invention without departing from the scope of the appended claims. Accordingly, the scope of the appended claims is not to be limited to the specific embodiments described above.

Claims (12)

1. A charging power switch control signal generation circuit, comprising:
the controller is used for detecting whether the battery is allowed to be charged or not and outputting a corresponding first control signal through an output end of the controller;
the first MOS tube is connected with the first detection end at a first connection end, is connected with the charging control end at a second connection end, and is connected with the output end of the controller at a control end;
the first resistor and the second resistor are sequentially connected in series between the charging control end and the second detection end;
a first connecting end of the second MOS tube is connected with a charging control end, a second connecting end of the second MOS tube is connected with a connecting node between the first resistor and the second resistor, and a control end of the second MOS tube is connected with an output end of the charging overcurrent detection circuit;
and the charging overcurrent detection circuit is used for detecting whether the battery is charged and overcurrent or not and outputting a corresponding second control signal through an output end of the charging overcurrent detection circuit.
2. The charging power switch control signal generation circuit of claim 1,
when the fact that the battery is allowed to be charged is detected, the controller controls the first MOS tube to be conducted through the output end of the controller; when the situation that the battery is forbidden to be charged is detected, the controller controls the first MOS tube to be turned off through the output end of the controller;
when the charging overcurrent detection circuit detects that the battery is not in overcurrent during charging, the charging overcurrent detection circuit controls the second MOS tube to be cut off through the output end of the charging overcurrent detection circuit; when the charging overcurrent of the battery is detected, the charging overcurrent detection circuit controls the conduction of the second MOS tube through the output end of the charging overcurrent detection circuit.
3. The charging-power-switch control-signal generating circuit of claim 2,
the first MOS tube and the second MOS tube are both PMOS transistors, and the first connecting end, the second connecting end and the control end of the first MOS tube and the second MOS tube are respectively a source electrode, a drain electrode and a grid electrode of the PMOS transistor;
and the substrate ends of the first MOS tube and the second MOS tube are connected with the first detection end.
4. The charging-power-switch control-signal generating circuit of claim 3,
the first power supply end of the charging overcurrent detection circuit is connected with the first detection end, the second power supply end of the charging overcurrent detection circuit is connected with the third detection end,
when the charging overcurrent of the battery is detected, the voltage of a first control signal output by the output end of the charging overcurrent detection circuit to the control end of the second MOS tube is equal to the voltage of the third detection end G, so that the second MOS tube is conducted.
5. The charging-power-switch control-signal generating circuit of claim 3,
the first detection end is a connection end of the battery protection circuit and the positive electrode of the battery core; the second detection end is a connection end for connecting the battery protection circuit with the negative electrode of the battery; the third detection end is a connection end of the battery protection circuit and the negative electrode of the battery core,
the first resistance is greater than or equal to 106Ohm; the second resistance is less than or equal to 500 ohms.
6. A battery protection circuit comprising a second detection terminal connected to a negative electrode of a battery, a third detection terminal connected to a negative electrode of a battery, a first detection terminal connected to a positive electrode of a battery, a discharge control terminal connected to a control terminal of a discharge power switch, and a charge control terminal connected to a control terminal of a charge power switch, wherein the discharge power switch and the charge power switch are connected between the third detection terminal and the second detection terminal, characterized in that it further comprises a charge power switch control signal generating circuit according to any one of claims 1 to 5.
7. A charging power switch control signal generation circuit, comprising:
the controller is used for detecting whether the battery is allowed to be charged or not and outputting a corresponding first control signal through an output end of the controller;
the first MOS tube is connected with the first detection end V at a first connection end, is connected with the charging control end at a second connection end, and is connected with the output end of the controller at a control end;
the first resistor, the third resistor and the second resistor are sequentially connected in series between the charging control end and the second detection end;
a first connecting end of the second MOS tube is connected with the charging control end, and a second connecting end of the second MOS tube is connected with a connecting node between the first resistor and the third resistor;
the first connection end of the third MOS tube is connected with the first detection end, the second connection end of the third MOS tube is connected with the control end of the second MOS tube, and the control end of the third MOS tube is connected with the output end of the charging overcurrent detection circuit;
one end of the fourth resistor is connected with the second connecting end of the third MOS tube, the other end of the fourth resistor is connected with a connecting node between the third resistor and the second resistor,
and the charging overcurrent detection circuit is used for detecting whether the battery is charged and overcurrent or not and outputting a corresponding third control signal through an output end of the charging overcurrent detection circuit.
8. The charging power switch control signal generation circuit of claim 7,
when the fact that the battery is allowed to be charged is detected, the controller controls the first MOS tube to be conducted through the output end of the controller; when the situation that the battery is forbidden to be charged is detected, the controller controls the first MOS tube to be turned off through the output end of the controller;
when the charging overcurrent detection circuit detects that the battery is not charged and overcurrent, the charging overcurrent detection circuit controls the conduction of the third MOS tube through the output end of the charging overcurrent detection circuit, and the conduction of the third MOS tube enables the second MOS tube to be cut off; when the charging overcurrent of the battery is detected, the charging overcurrent detection circuit controls the third MOS tube to be switched off through the output end of the charging overcurrent detection circuit, and the third MOS tube is switched off to enable the second MOS tube to be switched on.
9. The charging-power-switch control-signal generating circuit of claim 8,
the first MOS transistor, the second MOS transistor and the third MOS transistor are PMOS transistors, and the first connecting end, the second connecting end and the control end of the first MOS transistor, the second MOS transistor and the third MOS transistor are respectively a source electrode, a drain electrode and a grid electrode of the PMOS transistor;
and the substrate ends of the first MOS tube, the second MOS tube and the third MOS tube are all connected with the first detection end.
10. The charging-power-switch control-signal generating circuit of claim 9,
the first power supply end of the charging overcurrent detection circuit is connected with the first detection end, the second power supply end of the charging overcurrent detection circuit is connected with the third detection end,
when the charging overcurrent of the battery is detected, the charging overcurrent detection circuit controls the third MOS tube to be switched off, and at the moment, the voltage of the control end of the second MOS tube is smaller than that of the second detection end.
11. The charging-power-switch control-signal generating circuit of claim 9,
the first detection end is a connection end of the battery protection circuit and the positive electrode of the battery core; the second detection end is a connection end for connecting the battery protection circuit with the negative electrode of the battery; the third detection end is a connection end of the battery protection circuit and the negative electrode of the battery core,
the first resistance is greater than or equal to 106Ohm; the second resistance is less than or equal to 500 ohms.
12. A battery protection circuit comprising a second detection terminal connected to a negative electrode of a battery, a third detection terminal connected to a negative electrode of a battery, a first detection terminal connected to a positive electrode of a battery, a discharge control terminal connected to a control terminal of a discharge power switch, and a charge control terminal connected to a control terminal of a charge power switch, wherein the discharge power switch and the charge power switch are connected between the third detection terminal and the second detection terminal, characterized in that it further comprises a charge power switch control signal generating circuit according to any one of claims 6 to 11.
CN201911263428.4A 2019-08-29 2019-12-11 Battery protection circuit and charging power switch control signal generation circuit thereof Pending CN110829386A (en)

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CN201910804910 2019-08-29
CN2019108049108 2019-08-29

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2021179779A1 (en) * 2020-03-09 2021-09-16 深圳市创芯微微电子有限公司 Battery protection chip and battery protection board
CN114156960A (en) * 2020-10-30 2022-03-08 上海拜骋电器有限公司 Battery pack detection method and device and power management system
CN114421433A (en) * 2022-02-24 2022-04-29 合肥中感微电子有限公司 Battery protection circuit and charging power switch control signal generation circuit thereof

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2021179779A1 (en) * 2020-03-09 2021-09-16 深圳市创芯微微电子有限公司 Battery protection chip and battery protection board
CN114156960A (en) * 2020-10-30 2022-03-08 上海拜骋电器有限公司 Battery pack detection method and device and power management system
CN114421433A (en) * 2022-02-24 2022-04-29 合肥中感微电子有限公司 Battery protection circuit and charging power switch control signal generation circuit thereof
CN114421433B (en) * 2022-02-24 2023-09-12 合肥中感微电子有限公司 Battery protection circuit and charging power switch control signal generating circuit thereof

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