CN114043898A - Charger protection circuit and method and charger - Google Patents
Charger protection circuit and method and charger Download PDFInfo
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- CN114043898A CN114043898A CN202111212751.6A CN202111212751A CN114043898A CN 114043898 A CN114043898 A CN 114043898A CN 202111212751 A CN202111212751 A CN 202111212751A CN 114043898 A CN114043898 A CN 114043898A
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
- B60L53/00—Methods of charging batteries, specially adapted for electric vehicles; Charging stations or on-board charging equipment therefor; Exchange of energy storage elements in electric vehicles
- B60L53/60—Monitoring or controlling charging stations
- B60L53/62—Monitoring or controlling charging stations in response to charging parameters, e.g. current, voltage or electrical charge
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/60—Other road transportation technologies with climate change mitigation effect
- Y02T10/70—Energy storage systems for electromobility, e.g. batteries
-
- 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
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/60—Other road transportation technologies with climate change mitigation effect
- Y02T10/7072—Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T90/00—Enabling technologies or technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02T90/10—Technologies relating to charging of electric vehicles
- Y02T90/12—Electric charging stations
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Transportation (AREA)
- Mechanical Engineering (AREA)
- Charge And Discharge Circuits For Batteries Or The Like (AREA)
Abstract
The invention belongs to the technical field of chargers, and discloses a charger protection circuit and method and a charger. The charger protection circuit comprises an over-temperature protection circuit, a charging control circuit, a short-circuit protection circuit and an overvoltage protection circuit; the over-temperature protection circuit is used for outputting a working signal to the charging control circuit when the temperature of the charger is less than a temperature threshold value; the charging control circuit is used for converting the voltage provided by the commercial power into a charging voltage and outputting the charging voltage according to the working signal so as to charge the battery pack; the short-circuit protection circuit is used for consuming charging voltage when the two ends of the battery pack are short-circuited, so that short-circuit current is reduced; and the overvoltage protection circuit is used for outputting the charging voltage to the ground when the voltage at two ends of the battery pack exceeds a voltage threshold value, so that the battery pack is stopped from being charged. According to the charger, the circuit of the charger is improved, the protection circuit is designed aiming at common abnormal conditions of over-temperature, over-voltage and output short circuit, the charging is stopped in time, and the use safety of the charger is guaranteed.
Description
Technical Field
The invention relates to the technical field of chargers, in particular to a charger protection circuit and method and a charger.
Background
In an electric vehicle charging station, in order to ensure the charging safety of an electric vehicle, the working state of a charger is detected, and the charging is stopped when the working state is abnormal, so that the charger and a battery pack are prevented from being burnt. Common working abnormalities include over-temperature, over-voltage and short circuit, and if the work is continued in these working states, property loss or personal injury may be caused. There are circuits designed separately for the detection of each anomaly at present, but there are no designs integrated in the same segment of the circuit.
The above is only for the purpose of assisting understanding of the technical aspects of the present invention, and does not represent an admission that the above is prior art.
Disclosure of Invention
The invention mainly aims to provide a charger protection circuit, a charger protection method and a charger, and aims to solve the technical problem of how to timely disconnect charging when an abnormality occurs in the prior art.
In order to achieve the purpose, the invention provides a charger protection circuit which comprises an over-temperature protection circuit, a charging control circuit, a short-circuit protection circuit and an overvoltage protection circuit which are sequentially connected, wherein the charging control circuit is connected with a mains supply, and the short-circuit protection circuit and the overvoltage protection circuit are also connected with two ends of a battery pack;
the over-temperature protection circuit is used for outputting a working signal to the charging control circuit when the temperature of the charger is less than a temperature threshold value;
the charging control circuit is used for converting the voltage provided by the commercial power into a charging voltage and outputting the charging voltage according to the working signal so as to charge the battery pack;
the short-circuit protection circuit is used for consuming the charging voltage when the two ends of the battery pack are short-circuited, so that the short-circuit current is reduced;
the overvoltage protection circuit is used for outputting the charging voltage to the ground when the voltage at two ends of the battery pack exceeds a voltage threshold value, so that the battery pack is stopped being charged.
Optionally, the over-temperature protection circuit includes: the thermistor comprises a first resistor, a second resistor, a third resistor, a fourth resistor, a thermistor, a first triode, a second triode and a first diode; the first end of the thermistor is connected with the collector of the first triode, the emitter of the first triode is connected with the first end of the second resistor, the second end of the second resistor is connected with the first end of the first resistor, and the second end of the first resistor is connected with the second end of the thermistor;
the first end of the thermistor is also connected with the base electrode of the second triode, the emitter electrode of the third triode is connected with the reference voltage output end, the first end of the thermistor is also connected with one end of the fourth resistor, and the other end of the fourth resistor is connected with the reference voltage output end;
the collector of the second triode is connected with the base of the first triode, the base of the first triode is connected with one end of the third resistor, the other end of the third resistor is connected with the anode of the first diode, and the cathode of the first diode is connected with the signal input end of the charging control circuit.
Optionally, the thermistor is configured to output a cutoff signal to the first triode and the second triode when the temperature of the charger is less than the temperature threshold value, so that the first triode and the second triode are not conducted;
the second triode is used for outputting a working signal to the charging control circuit when the second triode is not conducted;
the thermistor is also used for outputting a conduction signal to the first triode when the temperature of the charger is greater than the temperature threshold value, and conducting the first triode;
the first triode is also used for outputting a shutdown signal to the charging control circuit when the first triode is conducted;
the charging control circuit is further configured to stop outputting the charging voltage according to the stop signal, so as to suspend charging the battery pack.
Optionally, the short-circuit protection circuit comprises: a fifth resistor, a sixth resistor, a fifth triode, a sixth triode and a first field effect transistor; the fifth resistor is connected in parallel between a source electrode and a drain electrode of the first field effect transistor, the source electrode of the first field effect transistor is connected with a voltage output end of the charging control circuit, the drain electrode of the first field effect transistor is connected with a first end of the sixth resistor, a grid electrode of the first field effect transistor is connected with a collector electrode of the third triode, an emitting electrode of the third triode is grounded, a base electrode of the third triode is connected with one end of the eighth resistor, the other end of the eighth resistor is connected with a second end of the sixth resistor, the second end of the sixth resistor is further connected with a first end of the seventh resistor, and the second end of the seventh resistor is grounded;
and the first end of the sixth resistor and the second end of the seventh resistor are respectively connected in parallel to the positive end and the negative end of the battery pack.
Optionally, the third triode is configured to output a cut-off signal to the first field-effect transistor when two ends of the battery pack are short-circuited, so that the first field-effect transistor is cut off;
and the fifth resistor is used for consuming the charging voltage in the form of heat energy when the first field effect transistor is cut off.
Optionally, the overvoltage protection circuit includes a second diode, a third diode, a ninth resistor, a first capacitor, and a second field effect transistor; the positive electrode and the negative electrode of the first capacitor are respectively connected to the positive end and the negative end of the battery pack in parallel, the anode of the second diode is connected with the positive electrode of the first resistor, the cathode of the second diode is connected with the cathode of the third diode, the anode of the third diode is connected with the first end of the ninth resistor, the second end of the ninth resistor is grounded, the anode of the third diode is further connected with the grid electrode of the second field-effect tube, the source electrode of the second field-effect tube is grounded, and the drain electrode of the second field-effect tube is connected with the cathode of the third diode.
Optionally, the third diode is configured to output a turn-on signal to the second fet when the voltage across the battery pack exceeds the voltage threshold, so as to turn on the second fet;
and the second field effect transistor is used for outputting the charging voltage to the ground when the second field effect transistor is conducted, so that the battery pack is short-circuited to stop charging.
Optionally, the first and third triodes are NPN-type triodes, the second triode is a PNP-type triode, and the first and second field effect transistors are N-channel field effect transistors.
In addition, in order to achieve the above object, the present invention further provides a charger protection method, which is applied to the charger protection circuit described above, wherein the charger protection circuit includes an over-temperature protection circuit, a charge control circuit, a short-circuit protection circuit and an overvoltage protection circuit, which are connected in sequence, wherein the charge control circuit is connected to a mains supply, and the short-circuit protection circuit and the overvoltage protection circuit are further connected to two ends of a battery pack;
the charger protection method comprises the following steps:
the over-temperature protection circuit outputs a working signal to the charging control circuit when the temperature of the charger is less than a temperature threshold value;
the charging control circuit converts the voltage provided by the commercial power into a charging voltage and outputs the charging voltage according to the working signal, so as to charge the battery pack;
the short-circuit protection circuit consumes the charging voltage when the two ends of the battery pack are short-circuited, so that the short-circuit current is reduced;
the overvoltage protection circuit outputs the charging voltage to ground when the voltage across the battery pack exceeds a voltage threshold, thereby stopping charging the battery pack.
In addition, in order to achieve the above object, the present invention further provides a charger, which includes a battery pack and the charger protection circuit described above.
According to the invention, a charger protection circuit is arranged, and comprises an over-temperature protection circuit, a charge control circuit, a short-circuit protection circuit and an overvoltage protection circuit which are sequentially connected, wherein the charge control circuit is connected with a mains supply, and the short-circuit protection circuit and the overvoltage protection circuit are also connected with two ends of a battery pack; the over-temperature protection circuit is used for outputting a working signal to the charging control circuit when the temperature of the charger is less than a temperature threshold value; the charging control circuit is used for converting the voltage provided by the commercial power into a charging voltage and outputting the charging voltage according to the working signal so as to charge the battery pack; the short-circuit protection circuit is used for consuming the charging voltage when the two ends of the battery pack are short-circuited, so that the short-circuit current is reduced; the overvoltage protection circuit is used for outputting the charging voltage to the ground when the voltage at two ends of the battery pack exceeds a voltage threshold value, so that the battery pack is stopped being charged. Through improving the charger circuit, the protection circuit is designed aiming at the common abnormity of over-temperature, over-voltage and output short circuit, the charging work is cut off in time, and the use safety of the charger is ensured.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.
Fig. 1 is a functional block diagram of a charger protection circuit according to an embodiment of the present invention;
fig. 2 is a schematic circuit structure diagram of a charger protection circuit according to an embodiment of the present invention;
fig. 3 is a schematic flow chart of a charger protection method according to a first embodiment of the present invention.
The reference numbers illustrate:
| reference numerals | Name (R) | Reference numerals | Name (R) | |
| 10 | Over-temperature protection circuit | C1 | |
|
| 20 | Charging control circuit | D1～D3 | First to |
|
| 30 | Short-circuit protection | GND | Ground | |
| 40 | Overvoltage protection circuit | R1～R9 | First to |
|
| 50 | Commercial power | NTC | Thermal resistor | |
| BAT | Battery pack | Q1～Q3 | First to third triodes | |
| Vref | Reference voltage output terminal | Q4、Q5 | First and second field effect transistors |
The implementation, functional features and advantages of the objects of the present invention will be further explained with reference to the accompanying drawings.
Detailed Description
It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
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.
It should be noted that all the directional indicators (such as up, down, left, right, front, and rear … …) in the embodiment of the present invention are only used to explain the relative position relationship between the components, the movement situation, etc. in a specific posture (as shown in the drawing), and if the specific posture is changed, the directional indicator is changed accordingly.
In addition, the descriptions related to "first", "second", etc. in the present invention are for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions in the embodiments may be combined with each other, but it must be based on the realization of those skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should be considered to be absent and not within the protection scope of the present invention.
Referring to fig. 1, fig. 1 is a functional block diagram of a charger protection circuit according to an embodiment of the present invention;
the charger protection circuit comprises an over-temperature protection circuit 10, a charging control circuit 20, a short-circuit protection circuit 30 and an overvoltage protection circuit 40 which are sequentially connected, wherein the charging control circuit 20 is connected to a mains supply 50, and the short-circuit protection circuit 30 and the overvoltage protection circuit 40 are also connected with two ends of a battery pack BAT.
The over-temperature protection circuit 10 is configured to output a working signal to the charging control circuit 20 when the temperature of the charger is less than a temperature threshold.
It can be understood that the over-temperature protection circuit 10 at least includes a thermal element and a switch element, and when the thermal element detects that the temperature of the charger is less than the temperature threshold, the thermal element sends a signal to control the switch element to operate, so as to output an operating signal to the charge control circuit 20.
It will be readily understood that when the sensor detects that the temperature of the charger is greater than the temperature threshold, the charge control circuit 20 is deactivated by the switching element, so as to stop charging the battery pack BAT.
The charging control circuit 20 is configured to convert the voltage provided by the commercial power 50 into a charging voltage according to the working signal and output the charging voltage, so as to charge the battery pack BAT.
It can be understood that the charging control circuit 20 at least includes a rectifier bridge for converting the ac power of the utility power 50 into dc power, a voltage reducing circuit for reducing the voltage of the dc power to a standard voltage during charging, and a battery pack BAT balancing circuit for individually controlling each battery in the battery pack BAT to extend the battery life.
The short-circuit protection circuit 30 is configured to consume the charging voltage when a short circuit occurs at both ends of the battery pack BAT, thereby reducing a short-circuit current.
It will be appreciated that the short-circuit protection circuit 30 includes at least a resistive element for reducing the short-circuit current by converting electrical energy into thermal energy consumption.
The overvoltage protection circuit 40 is configured to output the charging voltage to ground when a voltage across the battery pack BAT exceeds a voltage threshold, thereby stopping charging the battery pack BAT.
It is to be understood that the overvoltage protection circuit 40 includes at least a switching element that forms a short circuit loop through which the charging voltage is brought to ground when the voltage across the battery pack BAT exceeds a voltage threshold.
The embodiment provides a charger protection circuit, which comprises an over-temperature protection circuit 10, a charging control circuit 20, a short-circuit protection circuit 30 and an overvoltage protection circuit 40, which are connected in sequence, wherein the charging control circuit 20 is connected to a mains supply 50, and the short-circuit protection circuit 30 and the overvoltage protection circuit 40 are also connected to two ends of a battery pack BAT; the over-temperature protection circuit 10 is configured to output a working signal to the charging control circuit 20 when the temperature of the charger is less than a temperature threshold; the charging control circuit 20 is configured to convert a voltage provided by the commercial power 50 into a charging voltage according to the working signal and output the charging voltage, so as to charge the battery pack BAT; the short-circuit protection circuit 30 is configured to consume the charging voltage when a short circuit occurs at two ends of the battery pack BAT, so as to reduce a short-circuit current; the overvoltage protection circuit 40 is configured to output the charging voltage to ground when a voltage across the battery pack BAT exceeds a voltage threshold, thereby stopping charging the battery pack BAT. Through improving the charger circuit, the protection circuit is designed aiming at the common abnormity of over-temperature, over-voltage and output short circuit, the charging work is cut off in time, and the use safety of the charger is ensured.
Further, referring to fig. 2, fig. 2 is a schematic circuit structure diagram of a charger protection circuit according to an embodiment of the present invention;
the overheat protection circuit 10 includes: the circuit comprises first to fourth resistors R4, a thermistor NTC, a first triode Q1, a second triode Q2 and a first diode D1; a first end of the thermistor NTC is connected to a collector of the first transistor Q1, an emitter of the first transistor Q1 is connected to a first end of the second resistor R2, a second end of the second resistor R2 is connected to a first end of the first resistor R1, and a second end of the first resistor R1 is connected to a second end of the thermistor NTC.
The first end of the thermistor NTC is also connected with the base of the second triode Q2, the emitter of the third triode is connected with the reference voltage output end Vref, the first end of the thermistor NTC is also connected with one end of the fourth resistor R4, and the other end of the fourth resistor R4 is connected with the reference voltage output end Vref.
The collector of the second triode Q2 is connected with the base of the first triode Q1, the base of the first triode Q1 is connected with one end of the third resistor R3, the other end of the third resistor R3 is connected with the anode of the first diode D1, and the cathode of the first diode D1 is connected with the signal input end of the charging control circuit 20.
Further, with reference to fig. 2, the thermistor NTC is configured to output a cut-off signal to the first transistor Q1 and the second transistor Q2 when the temperature of the charger is less than the temperature threshold, so that the first transistor Q1 and the second transistor Q2 are not turned on.
It should be noted that, the thermistor NTC is a negative temperature coefficient thermistor NTC, the higher the temperature is, the lower the resistance value is, and when the thermistor NTC is at a normal temperature, the current on the fourth resistor R4 is very small, and the first transistor Q1 and the second transistor Q2 are not conductive.
The second transistor Q2 is used for outputting an operation signal to the charge control circuit 20 when it is not conducting.
It can be understood that when the first transistor Q1 is not conducting, its collector has no output, and at this time, there is no high level output to the charging control circuit 20, and the charger operates normally according to the low level at this time as the operating signal.
The thermistor NTC is further configured to output a conduction signal to the first triode Q1 when the temperature of the charger is greater than the temperature threshold, so as to conduct the first triode Q1.
It can be understood that when the temperature of the thermistor NTC reaches the temperature threshold, the voltage across the fourth resistor R4 increases, and the second transistor Q2 is turned on, so as to output a high level to the charge control circuit 20.
The first transistor Q1 is further configured to output a shutdown signal to the charge control circuit 20 when conducting.
It should be noted that the stop signal is the output high level at this time, and when the charge control circuit 20 receives the stop signal, the output of the charge voltage is stopped.
The charge control circuit 20 is further configured to stop outputting the charging voltage according to the shutdown signal, so as to suspend charging the battery pack BAT.
In addition, when the temperature of the thermistor NTC drops to the recovery temperature, the current flowing through the thermistor NTC and the first transistor Q1 is not enough to maintain the second transistor Q2 to be turned on, and at this time, the first transistor Q1 and the second transistor Q2 are both turned off, no high level is output, and the charger recovers to operate.
According to the embodiment, the charging is stopped after the temperature rises to the temperature threshold, and the charging is recovered when the temperature drops to the set value, so that the service life of the device is prolonged, and the use safety is improved.
Further, with continued reference to fig. 2, the short-circuit protection circuit 30 includes: a fifth resistor R8, an eighth resistor R8, a third triode Q3 and a first field effect transistor Q4; the fifth resistor R5 is connected in parallel between the source and the drain of the first fet Q4, the source of the first fet Q4 is connected to the voltage output terminal of the charge control circuit 20, the drain of the first fet Q4 is connected to the first end of the sixth resistor R6, the gate of the first fet Q4 is connected to the collector of the third transistor Q3, the emitter of the third transistor Q3 is grounded GND, the base of the third transistor Q3 is connected to one end of the eighth resistor R8, the other end of the eighth resistor R8 is connected to the second end of the sixth resistor R6, the second end of the sixth resistor R6 is further connected to the first end of the seventh resistor R7, and the second end of the seventh resistor R7 is grounded;
a first end of the sixth resistor R6 and a second end of the seventh resistor R7 are respectively connected in parallel to positive and negative ends of the battery pack BAT.
Further, with reference to fig. 2, the third transistor Q3 is configured to output a cut-off signal to the first fet Q4 to cut off the first fet Q4 when the two terminals of the battery pack BAT are short-circuited.
It is understood that when the battery pack BAT is short-circuited, the base voltage of the third transistor Q3 is 0V, and the third transistor Q3 is non-conductive, so that the first fet Q4 is turned off.
The fifth resistor R5 is used for dissipating the charging voltage in the form of heat energy when the first field effect transistor Q4 is turned off.
When the first fet Q4 is turned off, the fifth resistor R5 is changed in resistance to limit the short-circuit current. Because the fifth resistor R5 is connected in parallel with the first field effect transistor Q4, when the first field effect transistor Q4 is conducted in normal operation, the fifth resistor R5 is short-circuited, and power consumption is avoided.
It will be appreciated that the fifth resistor R5 is a high power resistor, such as a cement resistor, which functions to protect the circuit.
In the embodiment, the electric energy is consumed through the resistor, the charger is protected when the two ends of the battery pack BAT are short-circuited, and the use safety is improved.
Further, with continued reference to fig. 2, the overvoltage protection circuit 40 includes a second diode D2, a third diode D3, a ninth resistor R9, a first capacitor C1, and a second fet Q5; the positive electrode and the negative electrode of the first capacitor C1 are respectively connected in parallel to the positive end and the negative end of the battery pack BAT, the anode of the second diode D2 is connected to the positive electrode of the first resistor R1, the cathode of the second diode D2 is connected to the cathode of the third diode D3, the anode of the third diode D3 is connected to the first end of the ninth resistor R9, the second end of the ninth resistor R9 is grounded GND, the anode of the third diode D3 is further connected to the gate of the second fet Q5, the source of the second fet Q5 is grounded GND, and the drain of the second fet Q5 is connected to the cathode of the third diode D3.
Further, with continued reference to fig. 2, the third diode D3 is configured to output a turn-on signal to the second fet Q5 when the voltage across the battery pack BAT exceeds the voltage threshold, so as to turn on the second fet Q5.
It can be understood that when the voltage across the battery pack BAT is greater than the voltage threshold, the third diode D3 is broken down, the gate voltage of the second fet Q5 changes from low to high, the second fet Q5 is turned on, and the post-gate drain of the second fet Q5 is turned on.
The second fet Q5 is used to output a charging voltage to ground when turned on, thereby short-circuiting the battery pack BAT to stop charging.
It can be understood that when the second fet Q5 is turned on, the stroke is short-circuited, and the charging voltage flows into the ground GND directly through the second fet Q5 without passing through the battery pack BAT.
In this embodiment, when the voltage is too high, the battery pack BAT is short-circuited, thereby protecting the battery pack BAT and the charger itself.
Further, with continued reference to fig. 2, the first and third transistors Q1, Q3 are NPN transistors, the second transistor Q2 is a PNP transistor, and the first and second fets Q4, Q5 are N-channel fets.
Fig. 3 is a schematic flow chart of a charger protection method according to a first embodiment of the present invention.
Referring to fig. 3, the method is applied to the charger protection circuit as described above, where the charger protection circuit includes an over-temperature protection circuit, a charge control circuit, a short-circuit protection circuit and an overvoltage protection circuit, which are connected in sequence, where the charge control circuit is connected to the mains supply, and the short-circuit protection circuit and the overvoltage protection circuit are also connected to two ends of the battery pack;
the charger protection method comprises the following steps:
step S10: and the over-temperature protection circuit outputs a working signal to the charging control circuit when the temperature of the charger is less than a temperature threshold value.
It can be understood that the over-temperature protection circuit at least comprises a thermosensitive element and a switching element, and when the thermosensitive element detects that the temperature of the charger is less than a temperature threshold value, the thermosensitive element sends a signal to control the switching element to work, so that a working signal is output to the charging control circuit.
It is easy to understand that when the sensitive element detects that the temperature of the charger is greater than the temperature threshold value, the charging control circuit stops working through the switching element, thereby stopping charging the battery pack.
Step S20: and the charging control circuit converts the voltage provided by the commercial power into a charging voltage and outputs the charging voltage according to the working signal, so as to charge the battery pack.
It can be understood that the charging control circuit at least comprises a rectifier bridge, a voltage reduction circuit and a battery pack balancing circuit, wherein the rectifier bridge is used for converting alternating current of a mains supply into direct current, the voltage reduction circuit is used for reducing the voltage of the direct current to a standard voltage during charging, and the battery pack balancing circuit is used for achieving the effect of prolonging the service life of the batteries by independently controlling each battery in the battery pack.
Step S30: the short-circuit protection circuit consumes the charging voltage when a short circuit occurs at two ends of the battery pack, thereby reducing short-circuit current.
It will be appreciated that the short-circuit protection circuit comprises at least a resistive element for reducing the short-circuit current by converting electrical energy into thermal energy consumption.
Step S40: the overvoltage protection circuit outputs the charging voltage to ground when the voltage across the battery pack exceeds a voltage threshold, thereby stopping charging the battery pack.
It is understood that the overvoltage protection circuit comprises at least a switching element which forms a short-circuit loop through which the charging voltage is led to ground when the voltage across the battery exceeds a voltage threshold.
According to the embodiment, the protection method is designed aiming at common abnormalities such as over-temperature, over-voltage and output short circuit, so that the charging work is timely disconnected, and the use safety of the charger is guaranteed.
In addition, in order to achieve the above object, the present invention further provides a charger, which includes a battery pack and the charger protection circuit described above.
Since the charger adopts all the technical solutions of all the embodiments, all the beneficial effects brought by the technical solutions of the embodiments are at least achieved, and are not repeated herein.
It should be understood that the above is only an example, and the technical solution of the present invention is not limited in any way, and in a specific application, a person skilled in the art may set the technical solution as needed, and the present invention is not limited thereto.
It should be noted that the above-described work flows are only exemplary, and do not limit the scope of the present invention, and in practical applications, a person skilled in the art may select some or all of them to achieve the purpose of the solution of the embodiment according to actual needs, and the present invention is not limited herein.
In addition, the technical details that are not described in detail in this embodiment may refer to the charger protection circuit provided in any embodiment of the present invention, and are not described herein again.
Further, it is to be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or system. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a process, method, article, or system that comprises the element.
The above-mentioned serial numbers of the embodiments of the present invention are merely for description and do not represent the merits of the embodiments.
Through the above description of the embodiments, those skilled in the art will clearly understand that the method of the above embodiments can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware, but in many cases, the former is a better implementation manner. Based on such understanding, the technical solution of the present invention or portions thereof that contribute to the prior art may be embodied in the form of a software product, where the computer software product is stored in a storage medium (e.g. Read Only Memory (ROM)/RAM, magnetic disk, optical disk), and includes several instructions for enabling a terminal device (e.g. a mobile phone, a computer, a server, or a network device) to execute the method according to the embodiments of the present invention.
The above description is only a preferred embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, which are made by using the contents of the present specification and the accompanying drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.
Claims (10)
1. The charger protection circuit is characterized by comprising an over-temperature protection circuit, a charging control circuit, a short-circuit protection circuit and an overvoltage protection circuit which are sequentially connected, wherein the charging control circuit is connected with a mains supply, and the short-circuit protection circuit and the overvoltage protection circuit are also connected with two ends of a battery pack;
the over-temperature protection circuit is used for outputting a working signal to the charging control circuit when the temperature of the charger is less than a temperature threshold value;
the charging control circuit is used for converting the voltage provided by the commercial power into a charging voltage and outputting the charging voltage according to the working signal so as to charge the battery pack;
the short-circuit protection circuit is used for consuming the charging voltage when the two ends of the battery pack are short-circuited, so that the short-circuit current is reduced;
the overvoltage protection circuit is used for outputting the charging voltage to the ground when the voltage at two ends of the battery pack exceeds a voltage threshold value, so that the battery pack is stopped being charged.
2. The charger protection circuit of claim 1, wherein the over-temperature protection circuit comprises: the thermistor comprises a first resistor, a second resistor, a third resistor, a fourth resistor, a thermistor, a first triode, a second triode and a first diode; the first end of the thermistor is connected with the collector of the first triode, the emitter of the first triode is connected with the first end of the second resistor, the second end of the second resistor is connected with the first end of the first resistor, and the second end of the first resistor is connected with the second end of the thermistor;
the first end of the thermistor is also connected with the base electrode of the second triode, the emitter electrode of the third triode is connected with the reference voltage output end, the first end of the thermistor is also connected with one end of the fourth resistor, and the other end of the fourth resistor is connected with the reference voltage output end;
the collector of the second triode is connected with the base of the first triode, the base of the first triode is connected with one end of the third resistor, the other end of the third resistor is connected with the anode of the first diode, and the cathode of the first diode is connected with the signal input end of the charging control circuit.
3. The charger protection circuit of claim 2, wherein the thermistor is configured to output a cutoff signal to the first transistor and the second transistor when the temperature of the charger is less than the temperature threshold, so that the first transistor and the second transistor are not turned on;
the second triode is used for outputting a working signal to the charging control circuit when the second triode is not conducted;
the thermistor is also used for outputting a conduction signal to the first triode when the temperature of the charger is greater than the temperature threshold value, and conducting the first triode;
the first triode is also used for outputting a shutdown signal to the charging control circuit when the first triode is conducted;
the charging control circuit is further configured to stop outputting the charging voltage according to the stop signal, so as to suspend charging the battery pack.
4. The charger protection circuit of claim 1, wherein the short circuit protection circuit comprises: a fifth resistor, a sixth resistor, a fifth triode, a sixth triode and a first field effect transistor; the fifth resistor is connected in parallel between a source electrode and a drain electrode of the first field effect transistor, the source electrode of the first field effect transistor is connected with a voltage output end of the charging control circuit, the drain electrode of the first field effect transistor is connected with a first end of the sixth resistor, a grid electrode of the first field effect transistor is connected with a collector electrode of the third triode, an emitting electrode of the third triode is grounded, a base electrode of the third triode is connected with one end of the eighth resistor, the other end of the eighth resistor is connected with a second end of the sixth resistor, the second end of the sixth resistor is further connected with a first end of the seventh resistor, and the second end of the seventh resistor is grounded;
and the first end of the sixth resistor and the second end of the seventh resistor are respectively connected in parallel to the positive end and the negative end of the battery pack.
5. The charger protection circuit according to claim 4, wherein the third triode is configured to output a cutoff signal to the first field effect transistor to cut off the first field effect transistor when the two ends of the battery pack are short-circuited;
and the fifth resistor is used for consuming the charging voltage in the form of heat energy when the first field effect transistor is cut off.
6. The charger protection circuit according to claim 1, wherein the overvoltage protection circuit comprises a second diode, a third diode, a ninth resistor, a first capacitor and a second field effect transistor; the positive electrode and the negative electrode of the first capacitor are respectively connected to the positive end and the negative end of the battery pack in parallel, the anode of the second diode is connected with the positive electrode of the first resistor, the cathode of the second diode is connected with the cathode of the third diode, the anode of the third diode is connected with the first end of the ninth resistor, the second end of the ninth resistor is grounded, the anode of the third diode is further connected with the grid electrode of the second field-effect tube, the source electrode of the second field-effect tube is grounded, and the drain electrode of the second field-effect tube is connected with the cathode of the third diode.
7. The charger protection circuit of claim 6, wherein the third diode is configured to output a turn-on signal to the second fet when the voltage across the battery pack exceeds the voltage threshold, thereby turning on the second fet;
and the second field effect transistor is used for outputting the charging voltage to the ground when the second field effect transistor is conducted, so that the battery pack is short-circuited to stop charging.
8. The charger protection circuit according to any one of claims 1 to 7, wherein the first and third transistors are NPN transistors, the second transistor is PNP transistor, and the first and second FETs are N-channel FETs.
9. A charger protection method is characterized in that the method is applied to the charger protection circuit according to any one of claims 1 to 8, the charger protection circuit comprises an over-temperature protection circuit, a charge control circuit, a short-circuit protection circuit and an overvoltage protection circuit which are sequentially connected, wherein the charge control circuit is connected with a mains supply, and the short-circuit protection circuit and the overvoltage protection circuit are also connected with two ends of a battery pack;
the charger protection method comprises the following steps:
the over-temperature protection circuit outputs a working signal to the charging control circuit when the temperature of the charger is less than a temperature threshold value;
the charging control circuit converts the voltage provided by the commercial power into a charging voltage and outputs the charging voltage according to the working signal, so as to charge the battery pack;
the short-circuit protection circuit consumes the charging voltage when the two ends of the battery pack are short-circuited, so that the short-circuit current is reduced;
the overvoltage protection circuit outputs the charging voltage to ground when the voltage across the battery pack exceeds a voltage threshold, thereby stopping charging the battery pack.
10. A charger, characterized in that, the charger includes a battery pack and a charger protection circuit according to any one of claims 1 to 8.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111212751.6A CN114043898A (en) | 2021-10-18 | 2021-10-18 | Charger protection circuit and method and charger |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111212751.6A CN114043898A (en) | 2021-10-18 | 2021-10-18 | Charger protection circuit and method and charger |
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| CN114043898A true CN114043898A (en) | 2022-02-15 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202111212751.6A Pending CN114043898A (en) | 2021-10-18 | 2021-10-18 | Charger protection circuit and method and charger |
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