CN114928147B - Battery charging protection circuit, chip and power module - Google Patents

Battery charging protection circuit, chip and power module Download PDF

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Publication number
CN114928147B
CN114928147B CN202210825903.8A CN202210825903A CN114928147B CN 114928147 B CN114928147 B CN 114928147B CN 202210825903 A CN202210825903 A CN 202210825903A CN 114928147 B CN114928147 B CN 114928147B
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China
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voltage
battery
resistor
unit
buck circuit
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CN202210825903.8A
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CN114928147A (en
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王琦桀
刘彬
陈博
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Shanghai Xinlong Semiconductor Technology Co ltd Nanjing Branch
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Shanghai Xinlong Semiconductor Technology Co ltd Nanjing Branch
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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
    • H02J7/00304—Overcurrent protection
    • 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
    • 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
    • H02J7/00308—Overvoltage protection
    • 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
    • H02J7/0034—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits using reverse polarity correcting or protecting circuits
    • 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
    • H02J7/0047—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with monitoring or indicating devices or circuits
    • 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
    • H02J7/0047—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with monitoring or indicating devices or circuits
    • H02J7/0048—Detection of remaining charge capacity or state of charge [SOC]
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
    • H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
    • H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
    • H02M3/158—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load
    • 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
    • H02J2207/00—Indexing scheme relating to details of circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J2207/20—Charging or discharging characterised by the power electronics converter
    • 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

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

Abstract

The invention relates to the technical field of circuits, in particular to a battery charging protection circuit, a chip and a power module. Whether the charging voltage and the charging current of the load battery are overlarge is detected through the current and voltage sampling unit, so that the BUCK circuit is controlled to be switched on or off, and the overcurrent and overvoltage protection problems of the load battery are solved; whether the power supply is disconnected or not is detected through the power supply voltage detection unit, so that the BUCK circuit is controlled to be connected or disconnected, and the problem of battery backflow is solved; whether the polarity of the load battery is reversed is detected through the battery voltage detection unit, and then the battery voltage switching unit switches the circuit according to the detection result of the battery voltage detection unit, so that the voltage output positive pole VOUT + of the BUCK circuit is connected to the positive pole of the load battery, the voltage output negative pole VOUT-of the BUCK circuit is connected to the negative pole of the load battery, the non-polarity connection of the load battery is realized, and the stability and the safety of a power module in the battery charging process are ensured.

Description

Battery charging protection circuit, chip and power module
Technical Field
The invention relates to the technical field of circuits, in particular to a battery charging protection circuit, a chip and a power module.
Background
The power module is required to monitor the voltage, current, temperature and the like of the load battery in the process of charging the load battery so as to ensure the safety of the load battery. Common load battery protection measures include overvoltage protection, overcurrent protection and overtemperature protection. Besides the above protection measures, in the process of charging the load battery by the power supply module, the functions of non-polar connection of the load battery, backflow prevention of the load battery and the like are also needed to ensure the stability and safety of the process of charging the load battery by the power supply module.
In the process that the power module charges the load battery, when the polarity of the load battery is reversed, the power module and the load battery are easily damaged, and even disastrous results such as load battery explosion and the like can be caused seriously. In the process that the power module charges the load battery, when the power supply of the power module is disconnected, the load battery can supply power to the power module in turn, so that the energy of the load battery is wasted, and the power module is damaged under certain conditions.
In the prior art, when the load battery polarity is reversed, a common solution is that the power supply module stops charging the load battery to avoid damage to the load battery and other catastrophic consequences, but there is no solution that can continue charging when the polarity is reversed. In order to avoid the backflow of the load battery, a common solution is to connect a diode in series in front of the load battery, and although the method is simple to implement, the diode has a large conduction voltage drop, so that a large loss is caused during large-current charging, and the efficiency of the power module is reduced.
Disclosure of Invention
The invention aims to solve the problems that the existing charging circuit consumes too much power and can not realize the non-polar connection of a battery, and the like, and provides a battery charging protection circuit, a chip and a power module.
In order to achieve the above object, the present invention provides a battery charge protection circuit, including: the device comprises a BUCK circuit, a power supply voltage detection unit, a current and voltage sampling unit, a battery voltage detection unit and a battery voltage switching unit;
the BUCK circuit is provided with a voltage output positive electrode VOUT + and a voltage output negative electrode VOUT-and is used for generating a positive electrode output voltage signal VOUT and a negative electrode output voltage signal according to a power supply voltage signal VIN input by an external power supply to charge an external load battery;
the power supply voltage detection unit is used for comparing a positive output voltage signal VOUT of the BUCK circuit with a power supply voltage signal VIN of a power supply, judging that the power supply voltage signal VIN disappears when the difference value between the positive output voltage signal VOUT and the power supply voltage signal VIN is smaller than a preset value, and sending a control signal to the BUCK circuit to control the BUCK circuit to be turned off;
the current and voltage sampling unit is used for overcurrent and overvoltage protection of a load battery, the current and voltage sampling unit acquires the charge cut-off current and the charge cut-off voltage of the load battery, compares the charge cut-off current with current signals at two ends of the load battery, compares the charge cut-off voltage with voltage signals at two ends of the load battery, judges whether the voltage signals at two ends of the load battery exceed the charge cut-off voltage or not, judges whether the current signals at two ends of the load battery exceed the charge cut-off current or not, and controls the BUCK circuit to be switched off when the voltage signals exceed the charge cut-off voltage or not;
the battery voltage detection unit is used for detecting whether the polarity of the load battery is reversed, the battery voltage switching unit is used for switching the circuit according to the detection result of the battery voltage detection unit, the battery voltage detection unit controls the battery voltage switching unit to switch and connect the voltage output positive pole VOUT + of the BUCK circuit to the positive pole of the load battery, and the voltage output negative pole VOUT-of the BUCK circuit is switched and connected to the negative pole of the load battery, so that the nonpolar connection of the load battery is realized.
As an implementation manner, a first end of the BUCK circuit is connected to a first power connection end P1, the first power connection end P1 is used for connecting a positive electrode of a power supply, a second end of the BUCK circuit is connected to a second power connection end P2, the second power connection end P2 is used for connecting a negative electrode of the power supply, a third end of the BUCK circuit is connected to one end of an internal power supply voltage unit VCC, the other end of the internal power supply voltage unit VCC is connected to one end of an internal working voltage unit VDD, the other end of the internal working voltage unit VDD is connected to a first end of a rectifier bridge, a second end of the rectifier bridge is connected to a first battery connection end P3, the first battery connection end P3 is used for connecting one electrode of a load battery, a third end of the rectifier bridge is connected to a second battery connection end P4, the first battery connection end P3 is used for connecting the other electrode of the load battery, and a fourth end of the rectifier bridge is connected to a ground terminal; the second end of the power supply voltage detection unit is connected with the first power supply connection end P1, and the third end of the power supply voltage detection unit is connected with a voltage output anode VOUT + of the BUCK circuit; the fifth end of the BUCK circuit is connected with the first end of the current and voltage acquisition unit, the sixth end of the BUCK circuit is connected with one end of a resistor R9 and the first end of the battery voltage switching unit as the positive voltage output pole VOUT + of the BUCK circuit, the seventh end of the BUCK circuit is connected with one end of a resistor R8 and one end of a resistor RCS, the other end of the resistor R9 is connected with the other end of the resistor R8 and the second end of the current and voltage acquisition unit, and the other end of the resistor RCS is connected with the third end of the current and voltage acquisition unit and the second end of the battery voltage switching unit as the negative voltage output pole VOUT-of the BUCK circuit; the third end of the battery voltage switching unit is connected with the fourth end of the battery voltage switching unit, the first end of the battery voltage detection unit and the first battery connection end P3, and the fifth end of the battery voltage switching unit is connected with the sixth end of the battery voltage switching unit, the second end of the battery voltage detection unit and the second battery connection end P4; and the third end of the battery voltage detection unit is used as a detection signal output end and is connected with the seventh end of the battery voltage switching unit, and the fourth end of the battery voltage detection unit is connected with an internal working voltage unit VDD.
As an implementation, the BUCK circuit includes a first power transistor Q11, a second power transistor Q12, an input capacitor CIN, a diode D7, an output capacitor COUT, an inductor L1;
the first end of the BUCK circuit is connected with the third end of the BUCK circuit, the drain of the second power tube Q12 and one end of an input capacitor CIN, the other end of the input capacitor CIN is connected with the anode of a diode D7, one end of an output capacitor COUT, the second end of the BUCK circuit and the seventh end of the BUCK circuit, the gate of the second power tube Q12 is connected with the fourth end of the BUCK circuit, the source of the second power tube Q12 is connected with the source of the first power tube Q11, the drain of the first power tube Q11 is connected with the cathode of the diode D7 and one end of an inductor L1, the gate of the first power tube Q11 is connected with the fifth end of the BUCK circuit, and the other end of the inductor L1 is connected with the other end of the output capacitor COUT and the sixth end of the BUCK circuit.
As an implementation manner, the power supply voltage detection unit includes a resistor R1, a resistor R2, a comparator E1, a resistor R3, a resistor R4, a triode Q1, and a second power tube driving control unit;
the first end of the power supply voltage detection unit is connected with the second voltage signal output end of the second power tube drive control unit, the second voltage signal input end of the second power tube drive control unit is connected with the output end of the comparator E1, the third end of the power supply voltage detection unit is connected with one end of the connecting resistor R1, the other end of the resistor R1 is connected with one end of the resistor R2 and the negative input end of the comparator E1, the other end of the resistor R2 is connected with the grounding end, the second end of the power supply voltage detection unit is connected with the base electrode and the collector electrode of the triode Q1, the emitter electrode of the triode Q1 is connected with one end of the resistor R3, the other end of the resistor R3 is connected with one end of the resistor R4 and the positive input end of the comparator E1, and the other end of the resistor R4 is connected with the grounding end;
when the power supply voltage signal VIN disappears, the power supply voltage signal VIN input by the first power supply connection end P1 starts to decrease until the voltage difference between the power supply voltage signal VIN and the positive output voltage signal VOUT + output by the voltage output positive pole VOUT + of the BUCK circuit is smaller than a preset value, the second input voltage signal V2 input by the positive input end of the comparator E1 is smaller than the first input voltage signal V1 input by the negative input end of the comparator E1, so that the first output voltage signal VC sent by the output end of the comparator E1 to the voltage signal input end of the second power tube driving control unit is at a low level of 0V; when the output of the power supply voltage signal VIN is stable, the voltage difference between the power supply voltage signal VIN and the positive electrode output voltage signal VOUT is greater than a preset value, and the second input voltage signal V2 is greater than the first input voltage signal V1, so that the first output voltage signal VC sent by the output end of the comparator E1 to the voltage signal input end of the second power tube driving control unit is at a high level, and the amplitude of the high level is VCC;
when the first output voltage signal VC is at a high level and the amplitude of the high level is VCC, the second power tube driving control unit controls the conduction of a second power tube Q12, so that the conduction of the BUCK circuit is controlled; when the first output voltage signal VC is at a low level of 0V, the second power tube driving control unit controls the second power tube Q12 to turn off, thereby controlling the BUCK circuit to turn off.
As an implementation manner, when the preset value is 0.7V, the first input voltage signal V1 is generated by dividing the voltage by the resistor R1 and the resistor R2, that is, V1= R2/(R1 + R2) × VOUT; the second input voltage signal V2 is generated by dividing the voltage by the resistor R3 and the resistor R4, i.e., V2= R4/(R3 + R4) (VIN-0.7V), where R2/(R1 + R2) = R4/(R3 + R4), so that the reduction ratios of the first input voltage signal V1 and the second input voltage signal V2 are consistent.
As an implementation, the current-voltage sampling unit includes a first power tube driving control unit, a current sampling unit and a voltage sampling unit;
the first end of the current and voltage acquisition unit is connected with the control signal output end of the first power tube driving control unit, the control signal input end of the first power tube driving control unit is connected with the control signal output end of the current sampling unit and the control signal output end of the voltage sampling unit, the second end of the current and voltage acquisition unit is connected with the sampling voltage signal input end of the voltage sampling unit, and the third end of the current and voltage acquisition unit is connected with the sampling current signal input end of the current sampling unit;
the voltage sampling unit is used for detecting whether voltage signals at two ends of the load battery exceed a charging cut-off voltage or not according to the maximum output voltage of the BUCK circuit, namely the charging cut-off voltage of the load battery, which is acquired by the sampling voltage signal input end and set according to a resistor R8 and a resistor R9, when the voltage signals exceed the charging cut-off voltage, the voltage sampling unit sends a control signal to the first power tube driving control unit, and the first power tube driving control unit sends a control signal to the fifth end of the BUCK circuit to control the BUCK circuit to be disconnected, so that overvoltage protection of the load battery is realized; the current sampling unit is used for detecting whether current signals at two ends of the load battery exceed the charging cut-off current or not according to the maximum output current of the BUCK circuit, namely the charging cut-off current of the load battery, set by the resistor RCS and input by the sampling current signal input end, and when the current signals exceed the charging cut-off current, the current sampling unit sends a control signal to the fifth end of the BUCK circuit to control the BUCK circuit to be disconnected, so that overcurrent protection of the load battery is achieved.
As an implementation, the battery voltage detection unit includes a transistor Q3, a resistor R6, a resistor R5, a resistor R7, and a transistor Q4;
the third end of the battery voltage detection unit is connected with an emitting electrode of a triode Q3 and one end of a resistor R6, the base electrode of the triode Q3 is connected with one end of a resistor R7 and one end of a resistor R5, the collector electrode of the triode Q3 is connected with the fourth end of the battery voltage detection unit, the other end of the resistor R6 is connected with the other end of the resistor R5, the collector electrode of the triode Q4, the base electrode of the triode Q4 and the grounding end, the other end of the resistor R7 is connected with the first end of the battery voltage detection unit, and the second end of the battery voltage detection unit is connected with the emitting electrode of the triode Q4;
when the polarity of the load battery is not reversed, namely the second battery connecting end P4 is connected with the negative electrode of the load battery, and the first battery connecting end P3 is connected with the positive electrode of the load battery, the diode Q4 is conducted, the voltage of the load battery is divided by the resistor R5 and the resistor R7, so that the voltage of two ends of the resistor R5 is equal to the starting voltage of the triode Q3, the triode Q3 is conducted, and after the triode Q3 is conducted, a first detection signal VA sent to the third end of the battery voltage detection unit is a high level and a high level amplitude value VDD;
when the polarity of the load battery is reversed, namely the first battery connecting end P3 is connected with the negative electrode of the load battery, and the second battery connecting end P4 is connected with the positive electrode of the load battery, the triode Q4 is cut off reversely, the VBE voltage of the triode Q3 is the voltage at two ends of the resistor R5, the voltage at two ends of the resistor R5 is low level 0V when the triode Q4 is cut off reversely, so that the triode Q3 is cut off, and a first detection signal VA sent to the third end of the battery voltage detection unit is low level 0V.
As one possible embodiment, the battery voltage switching unit includes a diode D5, a diode D6, a mos tube Q5, a mos tube Q7, a mos tube Q6, a mos tube Q8, a mos tube Q9, a mos tube Q10, a resistor R11, a resistor R12, a resistor R13, a resistor R14, a phase inversion amplifier;
the first end of the battery voltage switching unit is connected with the cathode of the diode D5, the source electrode of the mos tube Q8, one end of the resistor R10, the cathode of the diode D6, one end of the resistor R12 and the source electrode of the mos tube Q9, the anode of the diode D5 is connected with the other end of the resistor R10, one end of the resistor R11 and the grid electrode of the mos tube Q8, the drain electrode of the mos tube Q8 is connected with the fourth end of the battery voltage switching unit, the anode of the diode D6 is connected with the other end of the resistor R12, one end of the resistor R13 and the grid electrode of the mos tube Q9, the drain electrode of the mos tube Q9 is connected with the fourth end of the battery voltage switching unit, the other end of the resistor R11 is connected with the drain electrode of the mos tube Q7, the other end of the resistor R13 is connected with the drain electrode of the mos tube Q10, the source electrode of the mos tube Q7 is connected with the second end of the battery voltage switching unit and the source electrode of the mos tube Q6, the grid electrode of the mos tube Q7 is connected with the grid electrode of the mos tube Q5 and the output end of the inverting amplifier NOT1, the source electrode of the mos tube Q10 is connected with the drain electrode of the mos tube Q6 and the sixth end of the battery voltage switching unit, the grid electrode of the mos tube Q6 is connected with the input end of the inverting amplifier NOT1, the grid electrode of the mos tube Q10 and the seventh end of the battery voltage switching unit, and the second end of the battery voltage switching unit is connected with the source electrode of the mos tube Q5;
when a first detection signal VA input at the seventh end of the battery voltage switching unit is at a high level and the amplitude of the high level is VDD, at this time, the mos tube Q6 and the mos tube Q10 are conducted, the mos tube Q9 is conducted after the mos tube Q10 is conducted, and the first detection signal VA outputs a second output voltage signal VB at a low level of 0V through the inverting amplifier NOT1, so that the mos tube Q5 and the mos tube Q7 are turned off, and the mos tube Q8 is turned off after the mos tube Q7 is turned off, so that the positive electrode of the load battery is connected to the positive output voltage VOUT + of the BUCK circuit through the first battery connection end P3, and the negative electrode of the load battery is connected to the negative output voltage VOUT-of the BUCK circuit through the second battery connection end P4;
when the first detection signal VA input at the seventh end of the battery voltage switching unit is at low level 0V, the mos tube Q6 and the mos tube Q10 are turned off, the mos tube Q9 is turned off after the mos tube Q10 is turned off, and the first detection signal VA outputs the second output voltage signal VB through the inverting amplifier NOT1 at high level, so that the mos tube Q5 and the mos tube Q7 are turned on, the mos tube Q8 is turned on after the mos tube Q7 is turned on, so that the positive electrode of the load battery is connected to the positive electrode VOUT + of the BUCK circuit voltage output through the second battery connection end P4, and the negative electrode of the load battery is connected to the negative electrode VOUT-of the BUCK circuit voltage output through the first battery connection end P3.
Correspondingly, the invention further provides a chip comprising the battery charging protection circuit, wherein the first power connection end P1, the second power connection end P2, the first battery connection end P3 and the second battery connection end P4 are all used as pins of the chip.
Correspondingly, the invention also provides a power supply module which comprises a power supply and the chip, wherein the anode of the power supply is connected with the first power supply connecting end P1, and the cathode of the power supply is connected with the second power supply connecting end P2.
The invention has the beneficial effects that: the invention provides a battery charging protection circuit, a chip and a power supply module, wherein a current and voltage sampling unit is used for detecting whether the charging voltage and the charging current of a load battery are overlarge, and a first power tube driving control unit is used for controlling the turn-off of a first power tube in a BUCK circuit, so that the problems of overcurrent protection and overvoltage protection of the load battery are solved; whether the power supply is disconnected or not is detected through the power supply voltage detection unit, and the second power tube driving control unit controls the turn-off of the second power tube in the BUCK circuit, so that the problem of preventing the battery from flowing backwards is solved; whether the polarity of the load battery is reversed is detected through the battery voltage detection unit, and then the battery voltage switching unit switches the circuit according to the detection result of the battery voltage detection unit, so that no matter whether the first battery connecting end P3 and the second battery connecting end P4 of the power supply module are connected to any one end electrode of the load battery, the positive pole VOUT + of the voltage output of the BUCK circuit is connected to the positive pole of the load battery, the negative pole VOUT-of the voltage output of the BUCK circuit is connected to the negative pole of the load battery, the non-polarity connection of the load battery is realized, and the stability and the safety of the power supply module in the battery charging process are ensured.
Drawings
FIG. 1 is a schematic diagram of a battery charging protection circuit according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a battery voltage switching unit of the battery charging protection circuit according to the embodiment of the present invention when the load battery is not connected with a reverse polarity;
FIG. 3 is a schematic diagram of a battery voltage switching unit of the battery charging protection circuit according to the embodiment of the present invention when the polarity of the load battery is connected in reverse;
fig. 4 is a schematic diagram illustrating voltage value changes of the positive output voltage signal VOUT, the power voltage signal VIN, and the first output voltage signal VC when the power supply is not disconnected or interrupted in the battery charging protection circuit according to the embodiment of the 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.
Referring to fig. 1, the present embodiment provides a technical solution: a battery charge protection circuit comprising: the device comprises a BUCK circuit STAGE1, a power supply voltage detection unit STAGE2, a current and voltage sampling unit STAGE3, a battery voltage detection unit STAGE4 and a battery voltage switching unit STAGE5;
the BUCK circuit STAGE1 has a voltage output positive electrode VOUT + and a voltage output negative electrode VOUT-, and is configured to generate a positive output voltage signal VOUT and a negative output voltage signal according to a power supply voltage signal VIN input by an external power supply 100, and charge an external load battery 200;
the power supply voltage detection unit STAGE2 is used for comparing a positive electrode output voltage signal VOUT of the BUCK circuit with a power supply voltage signal VIN of a power supply, judging that the power supply voltage signal VIN disappears when the difference value between the positive electrode output voltage signal VOUT and the power supply voltage signal VIN is smaller than a preset value, and sending a control signal to the BUCK circuit to control the BUCK circuit to be disconnected;
the current and voltage sampling unit STAGE3 is used for overcurrent and overvoltage protection of a load battery, the current and voltage sampling unit acquires the charge cut-off current and the charge cut-off voltage of the load battery, compares the charge cut-off current with current signals at two ends of the load battery, compares the charge cut-off voltage with voltage signals at two ends of the load battery, judges whether the voltage signals at two ends of the load battery exceed the charge cut-off voltage or not, judges whether the current signals at two ends of the load battery exceed the charge cut-off current or not, and controls the BUCK circuit to be turned off when the voltage signals exceed the charge cut-off voltage or not;
the battery voltage detection unit STAGE4 is used for detecting whether the polarity of the load battery is reversed, the battery voltage switching unit STAGE5 is used for switching the circuit according to the detection result of the battery voltage detection unit STAGE4, controlling the battery voltage detection unit by the battery voltage switching unit to switch and connect the voltage output positive pole VOUT + of the BUCK circuit to the positive pole of the load battery 200, and switching and connecting the voltage output negative pole VOUT-of the BUCK circuit to the negative pole of the load battery 200, so that the non-polarity connection of the load battery is realized.
Specifically, a first end of the BUCK circuit is connected to a first power connection end P1, the first power connection end P1 is used for connecting a positive electrode of a power supply, a second end of the BUCK circuit is connected to a second power connection end P2, the second power connection end P2 is used for connecting a negative electrode of the power supply, a third end of the BUCK circuit is connected to one end of an internal power supply voltage unit VCC, the other end of the internal power supply voltage unit VCC is connected to one end of an internal working voltage unit VDD, the other end of the internal working voltage unit VDD is connected to a first end of a rectifier bridge, a second end of the rectifier bridge is connected to a first battery connection end P3, the first battery connection end P3 is used for connecting one electrode of a load battery, a third end of the rectifier bridge is connected to a second battery connection end P4, the first battery connection end P3 is used for connecting another electrode of the load battery, and a fourth end of the rectifier bridge is connected to a ground terminal; the second end of the power supply voltage detection unit is connected with a first power supply connection end P1, and the third end of the power supply voltage detection unit is connected with a voltage output anode VOUT + of the BUCK circuit; the fifth end of the BUCK circuit is connected with the first end of the current and voltage acquisition unit, the sixth end of the BUCK circuit is connected with one end of a resistor R9 and the first end of the battery voltage switching unit as the positive voltage output pole VOUT + of the BUCK circuit, the seventh end of the BUCK circuit is connected with one end of a resistor R8 and one end of a resistor RCS, the other end of the resistor R9 is connected with the other end of the resistor R8 and the second end of the current and voltage acquisition unit, and the other end of the resistor RCS is connected with the third end of the current and voltage acquisition unit and the second end of the battery voltage switching unit as the negative voltage output pole VOUT-of the BUCK circuit; the third end of the battery voltage switching unit is connected with the fourth end of the battery voltage switching unit, the first end of the battery voltage detection unit and the first battery connection end P3, and the fifth end of the battery voltage switching unit is connected with the sixth end of the battery voltage switching unit, the second end of the battery voltage detection unit and the second battery connection end P4; and the third end of the battery voltage detection unit is used as a detection signal output end and is connected with the seventh end of the battery voltage switching unit, and the fourth end of the battery voltage detection unit is connected with an internal working voltage unit VDD.
The rectifier bridge is composed of a plurality of diodes, for example, as shown in fig. 1, the rectifier bridge may be composed of a diode D1, a diode D2, a diode D3, and a diode D4, the supply voltage VDD is connected to the cathode of the diode D1 and the cathode of the diode D3, the anode of the diode D3 is connected to the second end of the rectifier bridge and the cathode of the diode D4, the anode of the diode D1 is connected to the third end of the rectifier bridge and the cathode of the diode D2, and the anode of the diode D2 and the anode of the diode D4 are both connected to the fourth end of the rectifier bridge; the internal working voltage unit VDD obtains power from the output end of the rectifier bridge, namely the voltage signal VE output by the first end, and the second end and the third section of the rectifier bridge are used as input ends and connected with the P3 end and the P4 end of the load battery; the internal working voltage unit VDD supplies power to the battery voltage detection unit STAGE4, the battery voltage switching unit STAGE5 and other units; when the load battery is not connected, the voltage value of the first detection signal VA is equal to the voltage value of the second output voltage signal VB and is equal to 0V, so the mos transistors Q5, Q6, Q7, Q8, Q9, Q10, etc. in the battery voltage switching unit STAGE5 are all in the off state.
The internal power supply voltage unit VCC gets power from the power supply voltage signal VIN and the voltage signal VE output by the output end of the rectifier bridge, and the voltage amplitude of the internal power supply voltage unit VCC is smaller than the minimum value of the power supply voltage signal VIN and the voltage signal VE. The internal power supply voltage unit VCC supplies power to the power supply voltage detection unit STAGE2, the current and voltage sampling unit STAGE3 and other units.
The BUCK circuit comprises a first power tube Q11, a second power tube Q12, an input capacitor CIN, a diode D7, an output capacitor COUT and an inductor L1;
the first end of the BUCK circuit is connected with the third end of the BUCK circuit, the drain of the second power tube Q12 and one end of an input capacitor CIN, the other end of the input capacitor CIN is connected with the anode of a diode D7, one end of an output capacitor COUT, the second end of the BUCK circuit and the seventh end of the BUCK circuit, the gate of the second power tube Q12 is connected with the fourth end of the BUCK circuit, the source of the second power tube Q12 is connected with the source of the first power tube Q11, the drain of the first power tube Q11 is connected with the cathode of the diode D7 and one end of an inductor L1, the gate of the first power tube Q11 is connected with the fifth end of the BUCK circuit, and the other end of the inductor L1 is connected with the other end of the output capacitor COUT and the sixth end of the BUCK circuit.
The power supply voltage detection unit comprises a resistor R1, a resistor R2, a comparator E1, a resistor R3, a resistor R4, a triode Q1 and a second power tube driving control unit 10;
the first end of the power supply voltage detection unit is connected with a second voltage signal output end of the second power tube driving control unit, a second voltage signal input end of the second power tube driving control unit is connected with an output end of the comparator E1, a third end of the power supply voltage detection unit is connected with one end of the connecting resistor R1, the other end of the resistor R1 is connected with one end of the resistor R2 and a negative input end of the comparator E1, the other end of the resistor R2 is connected with a grounding end, a second end of the power supply voltage detection unit is connected with a base electrode and a collector electrode of the triode Q1, an emitting electrode of the triode Q1 is connected with one end of the resistor R3, the other end of the resistor R3 is connected with one end of the resistor R4 and a positive input end of the comparator E1, and the other end of the resistor R4 is connected with the grounding end;
when the power supply voltage signal VIN disappears, the power supply voltage signal VIN input by the first power supply connection terminal P1 starts to decrease until the voltage difference between the power supply voltage signal VIN and the positive output voltage signal VOUT + output by the voltage output positive pole VOUT + of the BUCK circuit is smaller than the preset value, the second input voltage signal V2 input by the positive input terminal of the comparator E1 is smaller than the first input voltage signal V1 input by the negative input terminal of the comparator E1, so that the first output voltage signal VC sent by the output terminal of the comparator E1 to the voltage signal input terminal of the second power tube driving control unit is at a low level of 0V; when the output of the power supply voltage signal VIN is stable, the voltage difference between the power supply voltage signal VIN and the positive electrode output voltage signal VOUT is greater than a preset value, and the second input voltage signal V2 is greater than the first input voltage signal V1, so that the first output voltage signal VC sent by the output end of the comparator E1 to the voltage signal input end of the second power tube driving control unit is at a high level, and the amplitude of the high level is VCC;
when the first output voltage signal VC is at a high level and the amplitude of the high level is VCC, the second power tube driving control unit controls the conduction of a second power tube Q12, so that the conduction of the BUCK circuit is controlled; when the first output voltage signal VC is at a low level of 0V, the second power tube driving control unit controls the second power tube Q12 to be turned off, so as to control the BUCK circuit to be turned off.
When the preset value is 0.7V, the first input voltage signal V1 is generated by dividing voltage by the resistor R1 and the resistor R2, that is, V1= R2/(R1 + R2) × VOUT; the second input voltage signal V2 is generated by dividing the voltage by the resistor R3 and the resistor R4, i.e., V2= R4/(R3 + R4) (VIN-0.7V), where R2/(R1 + R2) = R4/(R3 + R4), so that the reduction ratios of the first input voltage signal V1 and the second input voltage signal V2 are consistent.
Specifically, when the power supply stops outputting the power voltage signal VIN, that is, the power voltage signal VIN disappears, the voltage at the two ends of the input capacitor CIN begins to decrease, and the slope of the decrease is
Figure 32803DEST_PATH_IMAGE001
Wherein dv represents the voltage at two ends of an input capacitor CIN, dt represents time, CIN is the input capacitor of the BUCK circuit, and IIN is the input current of the BUCK circuit; when the voltage at the two ends of the input capacitor CIN is reduced to the voltage difference between the power supply voltage signal VIN and the positive electrode output voltage signal VOUT is less than 0.7V, the second power tube Q12 is controlled to be turned off, so that the phenomenon of battery backflow is prevented; when the voltage difference between the power supply voltage signal VIN and the positive output voltage signal VOUT is less than 0.7V, the voltage at the two ends of the CIN capacitor continues to drop, and the dropping speed depends on the resistor R3 and the resistor R4 resistance value; when the power supply is connected, the voltage of the CIN capacitor instantly rises to the voltage value of a power supply voltage signal VIN output by the power supply due to small loop impedance; when the voltage of the power supply voltage signal VIN output by the power supply is stable, the voltage difference between the power supply voltage signal VIN and the positive output voltage signal VOUT is much larger than 0.7V because the power supply module of the invention is based on the battery charging application of the BUCK circuit, that is, the power supply voltage signal VIN is much larger than the voltage of the load battery, so as to ensure that the battery can be normally charged.
As shown in fig. 4, VIN represents a voltage value of the power supply voltage signal VIN, VOUT represents a voltage value of the positive output voltage signal VOUT, and VC represents a voltage value of the first output voltage signal VC, wherein the power supply is normally powered up in a time period before a time point t1, the voltage values of the power supply voltage signal VIN are both much greater than VOUT, and the voltage value of the corresponding first output voltage signal VC is also output stably, and when the power supply is turned off, the voltage value of the power supply voltage signal VIN starts to fall until the time point t1 is reached, VIN-VOUT =0.7v, and the voltage value of the corresponding first output voltage signal VC starts to be 0, so that the second power tube Q12 is turned off, the BCUK circuit is turned off, and the charging of the load battery is stopped; and then, the voltage value of the power supply voltage signal VIN continuously decreases until the time point t2 is reached, the power supply is connected, VIN and VC are recovered instantaneously at the time point, the second power tube Q12 is started, and the BCUK circuit is conducted to normally charge the load battery.
According to the embodiment of the invention, the second power tube Q12 is added in the BUCK circuit, and the power supply voltage detection unit is used for detecting whether the power supply is supplying power or not, so that the switch of the second power tube Q12 is controlled according to the detection result, the function of preventing the battery from flowing backwards is realized, the loss during large-current charging is greatly reduced due to the use of the second power tube Q12, and the charging efficiency is improved.
The current and voltage sampling unit comprises a first power tube driving control unit 20, a current sampling unit 30 and a voltage sampling unit 40;
the first end of the current and voltage acquisition unit is connected with the control signal output end of the first power tube driving control unit 20, the control signal input end of the first power tube driving control unit 20 is connected with the control signal output end of the current sampling unit 30 and the control signal output end of the voltage sampling unit 40, the second end of the current and voltage acquisition unit is connected with the sampling voltage signal input end of the voltage sampling unit 40, and the third end of the current and voltage acquisition unit is connected with the sampling current signal input end of the current sampling unit 30;
the voltage sampling unit 40 is configured to detect whether voltage signals at two ends of the load battery exceed a charging cut-off voltage according to a maximum output voltage of the BUCK circuit, which is acquired by the sampling voltage signal input end and is set according to a resistor R8 and a resistor R9, that is, the charging cut-off voltage of the load battery, when the voltage signals exceed the charging cut-off voltage, the voltage sampling unit 40 sends a control signal to the first power tube driving control unit 20, the first power tube driving control unit 20 sends the control signal to a fifth end of the BUCK circuit to control the BUCK circuit to be disconnected, specifically, sends the control signal to the first power tube Q11 to control the first power tube Q11 to be disconnected, so that the BUCK circuit is disconnected, and overvoltage protection of the load battery is achieved;
the current sampling unit 30 is configured to detect whether a current signal at two ends of the load battery exceeds a charging cutoff current according to a maximum output current of the BUCK circuit, that is, a charging cutoff current of the load battery, which is set by the RCS and input by the sampling current signal input end, and when the current signal exceeds the charging cutoff current, the current sampling unit 30 sends a control signal to the first power tube driving control unit 20, and the first power tube driving control unit 20 sends a control signal to a fifth end of the BUCK circuit to control the BUCK circuit to be turned off, specifically, sends a control signal to the first power tube Q11 to control the first power tube Q11 to be turned off, so that the BUCK circuit is turned off, and overcurrent protection of the load battery is achieved.
The voltage sampling unit provided by the embodiment of the invention is supplied with power by VCC, and the maximum output voltage of the BUCK power supply part, namely the charging cut-off voltage of the load battery, can be changed by setting the resistor R8 and the resistor R9; when the voltage at the two ends of the battery exceeds the charge cut-off voltage, the voltage sampling unit sends a control signal to the first power tube driving control unit 20, so that the first power tube Q11 is turned off, and the overvoltage protection of the load battery is realized.
The current sampling unit provided by the embodiment of the invention is supplied with power by VCC, the maximum output current of the BUCK circuit part, namely the maximum current of battery charging, can be changed by setting the resistor RCS, and when the battery charging current is overlarge, the current sampling unit sends a control signal to the first power tube driving control unit 20 to turn off the first power tube Q11, so that the overcurrent protection of a load battery is realized.
The battery voltage detection unit comprises a triode Q3, a resistor R6, a resistor R5, a resistor R7 and a triode Q4;
the third end of the battery voltage detection unit is connected with an emitting electrode of a triode Q3 and one end of a resistor R6, the base electrode of the triode Q3 is connected with one end of a resistor R7 and one end of a resistor R5, the collector electrode of the triode Q3 is connected with the fourth end of the battery voltage detection unit, the other end of the resistor R6 is connected with the other end of the resistor R5, the collector electrode of the triode Q4, the base electrode of the triode Q4 and the grounding end, the other end of the resistor R7 is connected with the first end of the battery voltage detection unit, and the second end of the battery voltage detection unit is connected with the emitting electrode of the triode Q4;
when the polarity of the load battery is not reversed, namely the connection end P4 of the second battery is connected with the negative electrode of the load battery, and the connection end P3 of the first battery is connected with the positive electrode of the load battery, the diode Q4 is conducted, the voltage of the load battery is divided by the resistor R5 and the resistor R7, so that the voltage at two ends of the resistor R5 is equal to the starting voltage of the triode Q3, the triode Q3 is conducted, and after the triode Q3 is conducted, a first detection signal VA sent to the third end of the battery voltage detection unit is at a high level, namely a high level amplitude VDD;
when the polarity of the load battery is reversed, namely the first battery connecting end P3 is connected with the negative electrode of the load battery, and the second battery connecting end P4 is connected with the positive electrode of the load battery, the triode Q4 is reversely cut off, the VBE voltage of the triode Q3 is the voltage of two ends of the resistor R5, the voltage of two ends of the resistor R5 is low level 0V when the triode Q4 is reversely cut off, so the triode Q3 is turned off, and a first detection signal VA sent to the third end of the battery voltage detection unit is low level 0V.
The battery voltage switching unit comprises a diode D5, a diode D6, a mos tube Q5, a mos tube Q7, a mos tube Q6, a mos tube Q8, a mos tube Q9, a mos tube Q10, a resistor R11, a resistor R12, a resistor R13, a resistor R14 and a phase inversion amplifier;
the first end of the battery voltage switching unit is connected with the cathode of the diode D5, the source electrode of the mos tube Q8, one end of the resistor R10, the cathode of the diode D6, one end of the resistor R12 and the source electrode of the mos tube Q9, the anode of the diode D5 is connected with the other end of the resistor R10, one end of the resistor R11 and the grid electrode of the mos tube Q8, the drain electrode of the mos tube Q8 is connected with the fourth end of the battery voltage switching unit, the anode of the diode D6 is connected with the other end of the resistor R12, one end of the resistor R13 and the grid electrode of the mos tube Q9, the drain electrode of the mos tube Q9 is connected with the fourth end of the battery voltage switching unit, the other end of the resistor R11 is connected with the drain electrode of the mos tube Q7, the other end of the resistor R13 is connected with a drain electrode of a mos tube Q10, a source electrode of the mos tube Q7 is connected with a second end of the battery voltage switching unit and a source electrode of the mos tube Q6, a grid electrode of the mos tube Q7 is connected with a grid electrode of the mos tube Q5 and an output end of the inverting amplifier NOT1, a source electrode of the mos tube Q10 is connected with a drain electrode of the mos tube Q6 and a sixth end of the battery voltage switching unit, a grid electrode of the mos tube Q6 is connected with an input end of the inverting amplifier NOT1, a grid electrode of the mos tube Q10 and a seventh end of the battery voltage switching unit, and a second end of the battery voltage switching unit is connected with a source electrode of the mos tube Q5;
when a first detection signal VA input at the seventh end of the battery voltage switching unit is at a high level and the amplitude of the high level is VDD, at this time, the mos tube Q6 and the mos tube Q10 are conducted, the mos tube Q9 is conducted after the mos tube Q10 is conducted, and the first detection signal VA outputs a second output voltage signal VB at a low level of 0V through the inverting amplifier NOT1, so that the mos tube Q5 and the mos tube Q7 are turned off, and the mos tube Q8 is turned off after the mos tube Q7 is turned off, so that the positive electrode of the load battery is connected to the positive output voltage VOUT + of the BUCK circuit through the first battery connection end P3, and the negative electrode of the load battery is connected to the negative output voltage VOUT-of the BUCK circuit through the second battery connection end P4;
when the first detection signal VA input at the seventh end of the battery voltage switching unit is at low level 0V, the mos tube Q6 and the mos tube Q10 are turned off, the mos tube Q9 is turned off after the mos tube Q10 is turned off, and the first detection signal VA outputs the second output voltage signal VB through the inverting amplifier NOT1 at high level, so that the mos tube Q5 and the mos tube Q7 are turned on, the mos tube Q8 is turned on after the mos tube Q7 is turned on, so that the positive electrode of the load battery is connected to the positive electrode VOUT + of the BUCK circuit voltage output through the second battery connection end P4, and the negative electrode of the load battery is connected to the negative electrode VOUT-of the BUCK circuit voltage output through the first battery connection end P3.
Specifically, when the load cells are not connected in the reverse polarity, that is, the second cell connection end P4 is connected to the negative electrode of the load cell, and the first cell connection end P3 is connected to the positive electrode of the load cell, the first detection signal VA input from the third end of the cell voltage detection unit to the gate of the mos tube Q6 through the seventh end of the cell voltage switching unit is at a high level, and the amplitude of the high level is VDD, so that the mos tube Q6 and the mos tube Q10 are connected, and the mos tube Q9 is connected after the mos tube Q10 is connected, so that a path as shown in fig. 2 is formed, so that the positive electrode VOUT + of the BUCK circuit voltage output is connected to the positive electrode of the load cell through the mos tube Q9 and the first cell connection end P3; and because the second output voltage signal VB, which is sent to the grid of the mos tube Q5 and the grid of the mos tube Q7 by the first detection signal VA through the inverting amplifier NOT1, is low level 0V, the mos tube Q5 and the mos tube Q7 are turned off, and the mos tube Q8 is turned off after the mos tube Q7 is turned off, so that the negative electrode of the load battery is connected to the voltage output negative electrode VOUT-of the BUCK circuit through the second battery connecting end P4 and the mos tube Q6;
when the polarity of the load battery is connected in a reverse direction, that is, the first battery connection end P3 is connected to the negative electrode of the load battery, and the second battery connection end P4 is connected to the positive electrode of the load battery, the third end of the battery voltage detection unit inputs a first detection signal VA to the gate of the mos tube Q6 through the seventh end of the battery voltage switching unit, the mos tube Q9 is turned off after the mos tube Q10 is turned off, and a second output voltage signal VB sent by the first detection signal VA to the gate of the mos tube Q5 and the gate of the mos tube Q7 through the inverting amplifier NOT1 is high, so that the mos tube Q5 and the mos tube Q7 are connected, and the mos tube Q8 is connected after the mos tube Q7 is connected, so that a path as shown in fig. 3 is formed, and the positive electrode of the load battery is connected to the positive electrode VOUT + of the voltage output of the BUCK circuit through the second battery connection end P4 and the mos tube Q8, and the negative electrode of the load battery is connected to the negative electrode VOUT + of the BUCK circuit through the first battery connection end P3 and the negative voltage output circuit Q5.
The embodiment of the invention solves the practical application problem of battery polarity reversal through the battery voltage detection unit and the battery voltage switching unit, so that the first battery connection end P3 and the second battery connection end P4 can be connected with any end electrode of the load battery, namely whether the polarity of the load battery is reversed or not, the voltage output positive pole VOUT + of the BUCK circuit is finally connected to the positive pole of the load battery, and the voltage output negative pole VOUT-of the BUCK circuit is connected to the negative pole of the load battery, thereby realizing the charging of the battery and ensuring the stability and the safety of the battery charging process.
Based on the same inventive concept, an embodiment of the present invention further provides a chip, as shown in fig. 1, including: the battery charging protection circuit, wherein the first power connection terminal P1, the second power connection terminal P2, the first battery connection terminal P3 and the second battery connection terminal P4 are all pins of a chip.
Based on the same inventive concept, an embodiment of the present invention further provides a power module, as shown in fig. 1, including a power supply 100 and the chip, where a positive electrode of the power supply is connected to the first power connection end P1, and a negative electrode of the power supply is connected to the second power connection end P2.
Although the present invention has been described with reference to the preferred embodiments, it is not intended to limit the present invention, and those skilled in the art can make variations and modifications of the present invention without departing from the spirit and scope of the present invention by using the methods and technical contents disclosed above.

Claims (10)

1. A battery charge protection circuit, comprising: the device comprises a BUCK circuit, a power supply voltage detection unit, a current and voltage sampling unit, a battery voltage detection unit and a battery voltage switching unit;
the BUCK circuit is provided with a voltage output positive electrode VOUT + and a voltage output negative electrode VOUT-, and is used for generating a positive electrode output voltage signal VOUT and a negative electrode output voltage signal according to a power supply voltage signal VIN input by an external power supply to charge an external load battery;
the power supply voltage detection unit is used for comparing a positive output voltage signal VOUT of the BUCK circuit with a power supply voltage signal VIN of a power supply, judging that the power supply voltage signal VIN disappears when the difference value between the positive output voltage signal VOUT and the power supply voltage signal VIN is smaller than a preset value, and sending a control signal to the BUCK circuit to control the BUCK circuit to be turned off;
the current and voltage sampling unit is used for overcurrent and overvoltage protection of a load battery, the current and voltage sampling unit acquires the charge cut-off current and the charge cut-off voltage of the load battery, compares the charge cut-off current with current signals at two ends of the load battery, compares the charge cut-off voltage with voltage signals at two ends of the load battery, judges whether the voltage signals at two ends of the load battery exceed the charge cut-off voltage or not, judges whether the current signals at two ends of the load battery exceed the charge cut-off current or not, and controls the BUCK circuit to be switched off when the voltage signals exceed the charge cut-off voltage or not;
the battery voltage detection unit is used for detecting whether the polarity of a load battery is reversed, the battery voltage switching unit is used for switching the circuit according to the detection result of the battery voltage detection unit, the battery voltage detection unit controls the battery voltage switching unit to switch and connect the voltage output positive pole VOUT + of the BUCK circuit to the positive pole of the load battery, and the voltage output negative pole VOUT-of the BUCK circuit is switched and connected to the negative pole of the load battery, so that the non-polarity connection of the load battery is realized;
the first end of the battery voltage switching unit is used as a BUCK circuit voltage output positive pole VOUT +, the second end of the battery voltage switching unit is used as a BUCK circuit voltage output negative pole VOUT-, the third end of the battery voltage switching unit is connected with the fourth end of the battery voltage switching unit, the first end of the battery voltage detection unit and a first battery connection end P3 used for connecting one electrode of a load battery, and the fifth end of the battery voltage switching unit is connected with the sixth end of the battery voltage switching unit, the second end of the battery voltage detection unit and a second battery connection end P4 used for connecting the other electrode of the load battery; the seventh end of the battery voltage switching unit is connected with the third end of the battery voltage detection unit which is used as a detection signal output end;
the battery voltage switching unit comprises a diode D5, a diode D6, a mos tube Q5, a mos tube Q7, a mos tube Q6, a mos tube Q8, a mos tube Q9, a mos tube Q10, a resistor R11, a resistor R12, a resistor R13, a resistor R14 and a phase-inversion amplifier NOT1;
a first end of the battery voltage switching unit is connected with a cathode of the diode D5, a source of the mos transistor Q8, one end of the resistor R10, a cathode of the diode D6, one end of the resistor R12 and a source of the mos transistor Q9, an anode of the diode D5 is connected with the other end of the resistor R10, one end of the resistor R11 and a gate of the mos transistor Q8, a drain of the mos transistor Q8 is connected with a fourth end of the battery voltage switching unit, an anode of the diode D6 is connected with the other end of the resistor R12, one end of the resistor R13 and a gate of the mos transistor Q9, a drain of the mos transistor Q9 is connected with a fourth end of the battery voltage switching unit, the other end of the resistor R11 is connected with a drain of the mos transistor Q7, the other end of the resistor R13 is connected with a drain of the mos transistor Q10, a source of the mos transistor Q7 is connected with a second end of the battery voltage switching unit, a source of the mos transistor Q6, a gate of the mos transistor Q7 is connected with a gate of the mos transistor Q5, an output end of the amplifier inverter Q1, a source of the mos transistor Q10 is connected with a gate of the battery voltage switching unit, and a gate of the switching unit, a gate of the switching unit is connected with a gate of the switching unit, a gate of the switching unit Q5, a gate of the switching unit, and a gate of the switching unit.
2. The battery charging protection circuit according to claim 1, wherein a first end of the BUCK circuit is connected to a first power connection end P1, the first power connection end P1 is used for connecting to a positive electrode of a power supply, a second end of the BUCK circuit is connected to a second power connection end P2, the second power connection end P2 is used for connecting to a negative electrode of the power supply, a third end of the BUCK circuit is connected to one end of an internal power supply voltage unit VCC, the other end of the internal power supply voltage unit VCC is connected to one end of an internal working voltage unit VDD, the other end of the internal working voltage unit VDD is connected to a first end of a rectifier bridge, a second end of the rectifier bridge is connected to a first battery connection end P3, the third end of the rectifier bridge is connected to a second battery connection end P4, and a fourth end of the rectifier bridge is connected to a ground end; the second end of the power supply voltage detection unit is connected with the first power supply connection end P1, and the third end of the power supply voltage detection unit is connected with a voltage output anode VOUT + of the BUCK circuit; the fifth end of the BUCK circuit is connected with the first end of the current and voltage acquisition unit, the sixth end of the BUCK circuit is connected with one end of a resistor R9 and the first end of the battery voltage switching unit as a voltage output positive pole VOUT + of the BUCK circuit, the seventh end of the BUCK circuit is connected with one end of a resistor R8 and one end of a resistor RCS, the other end of the resistor R9 is connected with the other end of the resistor R8 and the second end of the current and voltage acquisition unit, and the other end of the resistor RCS is connected with the third end of the current and voltage acquisition unit and the second end of the battery voltage switching unit as a voltage output negative pole VOUT < - >; and the fourth end of the battery voltage detection unit is connected with an internal working voltage unit VDD.
3. The battery charging protection circuit of claim 2, wherein the BUCK circuit comprises a first power transistor Q11, a second power transistor Q12, an input capacitor CIN, a diode D7, an output capacitor COUT, an inductor L1;
the first end of the BUCK circuit is connected with the third end of the BUCK circuit, the drain of the second power tube Q12 and one end of an input capacitor CIN, the other end of the input capacitor CIN is connected with the anode of a diode D7, one end of an output capacitor COUT, the second end of the BUCK circuit and the seventh end of the BUCK circuit, the gate of the second power tube Q12 is connected with the fourth end of the BUCK circuit, the source of the second power tube Q12 is connected with the source of the first power tube Q11, the drain of the first power tube Q11 is connected with the cathode of the diode D7 and one end of an inductor L1, the gate of the first power tube Q11 is connected with the fifth end of the BUCK circuit, and the other end of the inductor L1 is connected with the other end of the output capacitor COUT and the sixth end of the BUCK circuit.
4. The battery charging protection circuit according to claim 3, wherein the power supply voltage detection unit comprises a resistor R1, a resistor R2, a comparator E1, a resistor R3, a resistor R4, a triode Q1 and a second power tube driving control unit;
the first end of the power supply voltage detection unit is connected with the second voltage signal output end of the second power tube driving control unit, the second voltage signal input end of the second power tube driving control unit is connected with the output end of the comparator E1, the third end of the power supply voltage detection unit is connected with one end of the resistor R1, the other end of the resistor R1 is connected with one end of the resistor R2 and the negative input end of the comparator E1, the other end of the resistor R2 is connected with the grounding end, the second end of the power supply voltage detection unit is connected with the base electrode and the collector electrode of the triode Q1, the emitter electrode of the triode Q1 is connected with one end of the resistor R3, the other end of the resistor R3 is connected with one end of the resistor R4 and the positive input end of the comparator E1, and the other end of the resistor R4 is connected with the grounding end;
when the power supply voltage signal VIN disappears, the power supply voltage signal VIN input by the first power supply connection terminal P1 starts to decrease until the voltage difference between the power supply voltage signal VIN and the positive output voltage signal VOUT + output by the voltage output positive pole VOUT + of the BUCK circuit is smaller than the preset value, the second input voltage signal V2 input by the positive input terminal of the comparator E1 is smaller than the first input voltage signal V1 input by the negative input terminal of the comparator E1, so that the first output voltage signal VC sent by the output terminal of the comparator E1 to the voltage signal input terminal of the second power tube driving control unit is at a low level of 0V; when the output of the power supply voltage signal VIN is stable, the voltage difference between the power supply voltage signal VIN and the positive electrode output voltage signal VOUT is greater than a preset value, and the second input voltage signal V2 is greater than the first input voltage signal V1, so that the first output voltage signal VC sent by the output end of the comparator E1 to the voltage signal input end of the second power tube driving control unit is at a high level, and the amplitude of the high level is VCC;
when the first output voltage signal VC is at a high level and the amplitude of the high level is VCC, the second power tube driving control unit controls the conduction of a second power tube Q12, so that the conduction of the BUCK circuit is controlled; when the first output voltage signal VC is at a low level of 0V, the second power tube driving control unit controls the second power tube Q12 to turn off, thereby controlling the BUCK circuit to turn off.
5. The battery charging protection circuit of claim 4, wherein when the preset value is 0.7V, the first input voltage signal V1 is generated by dividing a voltage by a resistor R1 and a resistor R2, i.e. V1= R2/(R1 + R2) × VOUT; the second input voltage signal V2 is generated by dividing the voltage by the resistor R3 and the resistor R4, i.e., V2= R4/(R3 + R4) (VIN-0.7V), where R2/(R1 + R2) = R4/(R3 + R4), so that the reduction ratios of the first input voltage signal V1 and the second input voltage signal V2 are consistent.
6. The battery charging protection circuit of claim 2, wherein the current voltage sampling unit comprises a first power tube driving control unit, a current sampling unit and a voltage sampling unit;
the first end of the current and voltage acquisition unit is connected with the control signal output end of the first power tube driving control unit, the control signal input end of the first power tube driving control unit is connected with the control signal output end of the current sampling unit and the control signal output end of the voltage sampling unit, the second end of the current and voltage acquisition unit is connected with the sampling voltage signal input end of the voltage sampling unit, and the third end of the current and voltage acquisition unit is connected with the sampling current signal input end of the current sampling unit;
the voltage sampling unit is used for detecting whether voltage signals at two ends of the load battery exceed a charging cut-off voltage or not according to the maximum output voltage of the BUCK circuit, namely the charging cut-off voltage of the load battery, which is acquired by the sampling voltage signal input end and set according to a resistor R8 and a resistor R9, when the voltage signals exceed the charging cut-off voltage, the voltage sampling unit sends a control signal to the first power tube driving control unit, and the first power tube driving control unit sends a control signal to the fifth end of the BUCK circuit to control the BUCK circuit to be disconnected, so that overvoltage protection of the load battery is realized; the current sampling unit is used for detecting whether current signals at two ends of the load battery exceed the charging cut-off current according to the maximum output current of the BUCK circuit set by the RCS and input by the sampling current signal input end, namely the charging cut-off current of the load battery, when the current signals exceed the charging cut-off current, the current sampling unit sends a control signal to the first power tube driving control unit, and the first power tube driving control unit sends a control signal to the fifth end of the BUCK circuit to control the BUCK circuit to be disconnected, so that overcurrent protection of the load battery is realized.
7. The battery charging protection circuit of claim 2, wherein the battery voltage detection unit comprises a transistor Q3, a resistor R6, a resistor R5, a resistor R7, and a transistor Q4;
the third end of the battery voltage detection unit is connected with an emitting electrode of a triode Q3 and one end of a resistor R6, the base electrode of the triode Q3 is connected with one end of a resistor R7 and one end of a resistor R5, the collector electrode of the triode Q3 is connected with the fourth end of the battery voltage detection unit, the other end of the resistor R6 is connected with the other end of the resistor R5, the collector electrode of the triode Q4, the base electrode of the triode Q4 and the grounding end, the other end of the resistor R7 is connected with the first end of the battery voltage detection unit, and the second end of the battery voltage detection unit is connected with the emitting electrode of the triode Q4;
when the polarity of the load battery is not reversed, namely the connecting end P4 of the second battery is connected with the negative electrode of the load battery, and the connecting end P3 of the first battery is connected with the positive electrode of the load battery, the triode Q4 is conducted, the voltage of the load battery is divided by the resistor R5 and the resistor R7, so that the voltage at two ends of the resistor R5 is equal to the starting voltage of the triode Q3, the triode Q3 is conducted, and after the triode Q3 is conducted, a first detection signal VA sent to the third end of the battery voltage detection unit is at a high level, namely a high level amplitude VDD;
when the polarity of the load battery is reversed, namely the first battery connecting end P3 is connected with the negative electrode of the load battery, and the second battery connecting end P4 is connected with the positive electrode of the load battery, the triode Q4 is cut off reversely, the VBE voltage of the triode Q3 is the voltage at two ends of the resistor R5, the voltage at two ends of the resistor R5 is low level 0V when the triode Q4 is cut off reversely, so that the triode Q3 is cut off, and a first detection signal VA sent to the third end of the battery voltage detection unit is low level 0V.
8. The battery charging protection circuit according to claim 7, wherein when the first detection signal VA inputted to the seventh terminal of the battery voltage switching unit is at a high level and the magnitude of the high level is VDD, the mos transistor Q6 and the mos transistor Q10 are turned on, the mos transistor Q9 is turned on after the mos transistor Q10 is turned on, and the second output voltage signal VB outputted by the first detection signal VA through the inverting amplifier NOT1 is at a low level of 0V, so the mos transistor Q5 and the mos transistor Q7 are turned off, and the mos transistor Q8 is turned off after the mos transistor Q7 is turned off, so that the positive electrode of the load battery is connected to the positive electrode of the voltage output of the BUCK circuit through the first battery connection terminal P3, and the negative electrode of the load battery is connected to the negative electrode VOUT "of the voltage output of the BUCK circuit through the second battery connection terminal P4;
when the first detection signal VA input at the seventh end of the battery voltage switching unit is at low level 0V, the mos tube Q6 and the mos tube Q10 are turned off, the mos tube Q9 is turned off after the mos tube Q10 is turned off, and the first detection signal VA outputs the second output voltage signal VB through the inverting amplifier NOT1 at high level, so that the mos tube Q5 and the mos tube Q7 are turned on, the mos tube Q8 is turned on after the mos tube Q7 is turned on, so that the positive electrode of the load battery is connected to the positive electrode VOUT + of the BUCK circuit voltage output through the second battery connection end P4, and the negative electrode of the load battery is connected to the negative electrode VOUT-of the BUCK circuit voltage output through the first battery connection end P3.
9. A chip, comprising: the battery charging protection circuit according to any one of claims 2 to 8, wherein the first power connection terminal P1, the second power connection terminal P2, the first battery connection terminal P3 and the second battery connection terminal P4 are all pins of a chip.
10. A power supply module, characterized in that it comprises a power supply and a chip according to claim 9, wherein the positive supply is connected to the first power supply connection P1 and the negative supply is connected to the second power supply connection P2.
CN202210825903.8A 2022-07-14 2022-07-14 Battery charging protection circuit, chip and power module Active CN114928147B (en)

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CN201222657Y (en) * 2008-06-06 2009-04-15 广州南科集成电子有限公司 Control integrated circuit for lithium battery charger and control circuit for polar change-over switch
CN111864838A (en) * 2020-07-20 2020-10-30 深圳拓邦股份有限公司 Self-adaptive battery polarity charging circuit and charger
CN216720938U (en) * 2021-07-19 2022-06-10 东莞市绿源新能电子有限公司 Intelligent non-polarity charging circuit

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CN101179198A (en) * 2006-11-08 2008-05-14 深圳迈瑞生物医疗电子股份有限公司 Synchronous commutation type battery charging circuit and protective circuit thereof
CN201222657Y (en) * 2008-06-06 2009-04-15 广州南科集成电子有限公司 Control integrated circuit for lithium battery charger and control circuit for polar change-over switch
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