CN109782049B - Charging circuit and voltage detection circuit thereof - Google Patents
Charging circuit and voltage detection circuit thereof Download PDFInfo
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- CN109782049B CN109782049B CN201910184902.8A CN201910184902A CN109782049B CN 109782049 B CN109782049 B CN 109782049B CN 201910184902 A CN201910184902 A CN 201910184902A CN 109782049 B CN109782049 B CN 109782049B
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Abstract
The application discloses charging circuit's voltage detection circuit includes: the output end of the resistance voltage division unit is connected with the input end of the voltage comparison unit and used for outputting a first detection voltage proportional to the charging voltage of the charging circuit; the voltage comparison unit is used for outputting a first comparison result signal to the mode adjusting circuit when the first detection voltage is lower than the first reference voltage, and the mode adjusting circuit adjusts the charging mode of the charging circuit into a constant current mode; the input end of the proportion adjusting unit is connected with the positive output end of the secondary side main circuit, and the output end of the proportion adjusting unit is connected with the resistance voltage dividing unit and used for reducing the voltage dividing proportion of the resistance voltage dividing unit when the charging voltage is larger than a preset threshold value. This application has increased the electric quantity when the battery is full of through improving the settlement voltage that charges in stage, has improved the battery utilization ratio, has also avoided the harm to battery life-span simultaneously. The application also discloses a charging circuit, also has above-mentioned beneficial effect.
Description
Technical Field
The application relates to the technical field of power supplies, in particular to a charging circuit and a voltage detection circuit thereof.
Background
With the widespread use of electronic devices, research on the charging problem of electronic devices has become a technical hotspot in the field. The charging process of the charging circuit in the prior art is simple, and only one charging set voltage is provided. At the beginning of charging, the voltage of the battery to be charged is low, so the circuit is charged quickly in a constant current mode (the charging current is large); when the voltage of the battery to be charged rises to approach the charging setting voltage, the circuit switches to charging in a constant voltage mode (the charging current is small) to prevent the battery from being overcharged, as shown in fig. 1. Because the service life of the battery is shortened due to the fact that the charging set voltage is too large, the battery can only be charged to 80% generally in the prior art, and the utilization rate is low. In view of the above, it is an important attention of those skilled in the art to provide a solution to the above technical problems.
Disclosure of Invention
The present application is directed to a charging circuit and a voltage detection circuit thereof, so as to effectively improve the charging utilization of a battery on the basis of ensuring the service life of the battery.
In order to solve the above technical problem, in a first aspect, the present application discloses a voltage detection circuit of a charging circuit, including a resistance voltage division unit, a proportion adjustment unit, and a voltage comparison unit;
the input end of the resistance voltage division unit is connected with the positive output end of a secondary side main circuit of the charging circuit, and the output end of the resistance voltage division unit is connected with the input end of the voltage comparison unit and used for outputting a first detection voltage proportional to the charging voltage of the charging circuit;
the output end of the voltage comparison unit is connected with the input end of a mode adjusting circuit of the charging circuit and used for outputting a first comparison result signal when the first detection voltage is lower than a first reference voltage, and the mode adjusting circuit adjusts the charging mode of the charging circuit into a constant current mode;
the input end of the proportion adjusting unit is connected with the positive output end of the secondary side main circuit, and the output end of the proportion adjusting unit is connected with the resistance voltage dividing unit and used for reducing the voltage dividing proportion of the resistance voltage dividing unit when the charging voltage is larger than a preset threshold value.
Optionally, the voltage comparison unit includes a first operational amplifier and a first reference voltage source; the inverting input end of the first operational amplifier is connected with the output end of the resistance voltage division unit, and the non-inverting input end of the first operational amplifier is connected with the first reference voltage source.
Optionally, the resistance voltage division unit includes a first resistance and a second resistance; the first end of the first resistor is connected with the positive output end of the secondary side main circuit; the second end of the first resistor is connected with the first end of the second resistor and serves as the output end of the resistor voltage division unit; and the second end of the second resistor is grounded.
Optionally, the proportional regulating unit includes a third resistor and a switching unit; the first end of the third resistor is connected with the first end of the second resistor, and the second end of the third resistor is grounded through the switch unit.
Optionally, the switching unit includes an MOS transistor, a second operational amplifier, a second reference voltage source, a fourth resistor, and a fifth resistor;
a first end of the fourth resistor is connected with a positive output end of the secondary side main circuit, a second end of the fourth resistor is respectively connected with a first end of the fifth resistor and a first input end of the second operational amplifier, and a second end of the fifth resistor is grounded; a second input end of the second operational amplifier is connected with the second reference voltage source; the output end of the second operational amplifier is connected with the control end of the MOS tube; and the first end of the MOS tube is connected with the second end of the third resistor, and the second end of the MOS tube is grounded.
Optionally, the first input terminal of the second operational amplifier is a non-inverting input terminal, and the second input terminal of the second operational amplifier is an inverting input terminal; the MOS tube is an NMOS tube.
Optionally, the switch unit further comprises a protection capacitor; the first end of the protection capacitor is connected with the control end of the MOS tube, and the second end of the protection capacitor is grounded.
In a second aspect, the present application further provides a charging circuit, including a primary side main circuit, a secondary side main circuit, a mode adjustment circuit, a current detection circuit, and any one of the voltage detection circuits described above;
the primary side main circuit is coupled with the secondary side main circuit through a transformer and is used for transmitting electric energy to the secondary side main circuit; the output end of the secondary side main circuit is connected with a battery to be charged and used for inputting rectified and stabilized direct current to the battery to be charged; the current detection circuit is used for detecting the working current of the secondary side main circuit; the voltage detection circuit is used for detecting the charging voltage of the secondary side main circuit; the mode adjusting circuit is coupled with the control module of the primary side main circuit and used for adjusting the charging mode of the charging circuit according to the working current and the charging voltage of the secondary side main circuit.
Optionally, the current detection circuit includes a sixth resistor, a seventh resistor, and a third operational amplifier;
a first end of the sixth resistor is connected with a negative input end of the secondary side main circuit, and a second end of the sixth resistor is connected with a positive input end of the third operational amplifier; a first end of the seventh resistor is connected with a negative output end of the secondary side main circuit, and a second end of the seventh resistor is connected with an inverting input end of the third operational amplifier; and the output end of the third operational amplifier is used as the output end of the current detection circuit.
Optionally, the mode adjustment circuit comprises an eighth resistor, an isolation optocoupler, a first diode, and a second diode;
a first end of the eighth resistor is connected with a positive input end of the secondary side main circuit, and a second end of the eighth resistor is connected with a positive input end of the isolation optocoupler; the negative input end of the isolation optocoupler is respectively connected with the anode of the first diode and the anode of the second diode, and the output end of the isolation optocoupler is coupled with the control module of the primary side main circuit; the cathode of the first diode is connected with the output end of the current detection unit, and the cathode of the second diode is connected with the output end of the voltage detection unit.
The voltage detection circuit of the charging circuit comprises a resistance voltage division unit, a proportion regulation unit and a voltage comparison unit; the input end of the resistance voltage division unit is connected with the positive output end of a secondary side main circuit of the charging circuit, and the output end of the resistance voltage division unit is connected with the input end of the voltage comparison unit and used for outputting a first detection voltage proportional to the charging voltage of the charging circuit; the output end of the voltage comparison unit is connected with the input end of a mode adjusting circuit of the charging circuit and used for outputting a first comparison result signal when the first detection voltage is lower than a first reference voltage, and the mode adjusting circuit adjusts the charging mode of the charging circuit into a constant current mode; the input end of the proportion adjusting unit is connected with the positive output end of the secondary side main circuit, and the output end of the proportion adjusting unit is connected with the resistance voltage dividing unit and used for reducing the voltage dividing proportion of the resistance voltage dividing unit when the charging voltage is larger than a preset threshold value.
Therefore, the proportion regulating circuit is utilized, the voltage division proportion of the resistance voltage division unit can be reduced after the charging voltage of the charging circuit is larger than the preset threshold value, namely the charging circuit enters the constant voltage mode from the constant current mode for the first time, the first detection voltage is lower than the first reference voltage, the corresponding first comparison result signal is output, the charging set voltage is further improved, and the charging circuit is converted into the constant current mode from the constant voltage mode again. This application has increased the electric quantity when the battery is full of effectively through improving the settlement voltage that charges in stage, has improved the battery utilization ratio, has also avoided directly improving the harm of settlement voltage that charges to the battery life-span simultaneously. The charging circuit that this application provided includes above-mentioned voltage detection circuit, has above-mentioned beneficial effect equally.
Drawings
In order to more clearly illustrate the technical solutions in the prior art and the embodiments of the present application, the drawings that are needed to be used in the description of the prior art and the embodiments of the present application will be briefly described below. Of course, the following description of the drawings related to the embodiments of the present application is only a part of the embodiments of the present application, and it will be obvious to those skilled in the art that other drawings can be obtained from the provided drawings without any creative effort, and the obtained other drawings also belong to the protection scope of the present application.
FIG. 1 is a schematic diagram of a charging process of a charging circuit in the prior art;
fig. 2 is a circuit structure diagram of a charging circuit and a voltage detection circuit thereof according to an embodiment of the present disclosure;
fig. 3 is a schematic diagram of a charging process of a charging circuit according to an embodiment of the present disclosure.
Detailed Description
The core of the application is to provide a charging circuit and a voltage detection circuit thereof, so as to effectively improve the charging utilization rate of a battery on the basis of guaranteeing the service life of the battery.
In order to more clearly and completely describe the technical solutions in the embodiments of the present application, the technical solutions in the embodiments of the present application will be described below with reference to the drawings in the embodiments of the present application. It is to be understood that the embodiments described are only a few embodiments of the present application and not all 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 application.
Referring to fig. 2, fig. 2 is a circuit structure diagram of a charging circuit and a voltage detection circuit thereof in an embodiment of the present application.
The voltage detection circuit of the charging circuit disclosed in the embodiment of the present application mainly includes a resistance voltage division unit 51, a proportion adjustment unit 52 and a voltage comparison unit 53;
an input end of the resistance voltage division unit 51 is connected with a positive output end of the secondary side main circuit 2 of the charging circuit, and an output end of the resistance voltage division unit 51 is connected with an input end of the voltage comparison unit 53 and used for outputting a first detection voltage proportional to the charging voltage of the charging circuit;
the output end of the voltage comparison unit 53 is connected to the input end of the mode adjustment circuit 3 of the charging circuit, and is configured to output a first comparison result signal when the first detection voltage is lower than the first reference voltage, and the mode adjustment circuit 3 adjusts the charging mode of the charging circuit to a constant current mode;
an input end of the proportional regulating unit 52 is connected with a positive output end of the secondary side main circuit 2, and an output end of the proportional regulating unit 52 is connected with the resistance voltage dividing unit 51, and is used for reducing the voltage dividing proportion of the resistance voltage dividing unit 51 when the charging voltage is greater than the preset threshold value.
Specifically, in the charging circuit, as mentioned above, there are generally two charging modes: a constant current mode and a constant voltage mode. If the electric quantity of the battery is low, the difference between the battery voltage and the charging set voltage is large (the initial stage of the charging process), the charging circuit works in a constant current mode, the battery is continuously charged by constant (large) working current, the battery voltage continuously rises until the battery voltage rises to be close to the charging set voltage, the charging circuit is switched to a constant voltage mode, the charging voltage basically keeps unchanged, and the charging current is reduced.
In the constant voltage mode, the battery is basically charged or discharged, and the electric quantity of the battery is mainly increased in the constant current mode stage. Therefore, in order to increase the amount of electricity when the battery is fully charged, the battery setting voltage needs to be increased. However, simply increasing the battery set voltage directly and operating the charging circuit at a relatively high voltage from the start of charging may impair the battery life.
Therefore, the voltage detection circuit of the charging circuit provided by the application can set two different charging set voltages in sequence in the charging process of the battery. Specifically, the voltage detection circuit provided by the present application includes a resistance voltage division unit 51 for detecting the charging voltage, a proportion adjustment unit 52 for reducing the resistance voltage division proportion when the charging voltage is greater than a preset threshold, and a voltage comparison unit 53 for comparing and determining the magnitude of the first detection voltage output by the resistance voltage division unit 51.
The voltage comparing unit 53 is connected to the mode adjusting circuit 3 of the charging circuit, and the mode adjusting circuit 3 can adjust the charging mode of the charging circuit according to the first comparison result signal output by the voltage comparing unit 53. As mentioned above, as the charging process continues, after the charging voltage of the battery approaches the initial charging setting voltage, the operation mode of the charging circuit will be switched from the initial constant current mode to the constant voltage mode. In order to enable the charging circuit to continue to charge the battery in the constant current mode, the ratio adjusting unit 52 in this application may decrease the voltage dividing ratio of the resistance voltage dividing unit 51 when the charging voltage is greater than the preset threshold (may be specifically set as the initial charging setting voltage, or slightly lower than the initial charging setting voltage), so that the first detection voltage is decreased and is smaller than the first reference voltage, the voltage comparing unit 53 outputs the first comparison result signal, and the mode adjusting circuit 3 adjusts the charging mode to the constant current mode again.
It should be noted that the adjustment of the charging mode by the mode adjustment circuit 3 can be realized by specifically increasing the charging setting voltage by the control module of the primary side main circuit 1 of the charging circuit. For example, a battery with a standard voltage of 12V has a battery voltage of generally 9V when initially discharged. When charging the battery, the initial charging set voltage may be 13V, and after a period of constant current mode (2A) charging, the charging voltage of the battery will slowly increase to 13V, the charging current will decrease to 0A, and the battery enters a constant voltage mode. At this time, after the proportional regulating unit 52 provided in the present application detects that the charging voltage reaches the preset threshold 13V, the voltage dividing proportion of the resistance voltage dividing unit 51 is reduced, so that the first detected voltage measured after the voltage dividing proportion is reduced is lower than the first reference voltage, the voltage comparing unit 53 outputs the first comparison result signal, the mode regulating circuit 3 utilizes the control module of the primary side main circuit 1 to increase the output duty ratio, and increase the charging setting voltage to 14V, so that the electric circuit works again in the constant current mode, so as to increase the electric quantity when the battery is fully charged.
The voltage detection circuit of the charging circuit provided by the application comprises a resistance voltage division unit 51, a proportion regulation unit 52 and a voltage comparison unit 53; an input end of the resistance voltage division unit 51 is connected with a positive output end of the secondary side main circuit 2 of the charging circuit, and an output end of the resistance voltage division unit 51 is connected with an input end of the voltage comparison unit 53 and used for outputting a first detection voltage proportional to the charging voltage of the charging circuit; the output end of the voltage comparison unit 53 is connected to the input end of the mode adjustment circuit 3 of the charging circuit, and is configured to output a first comparison result signal when the first detection voltage is lower than the first reference voltage, and the mode adjustment circuit 3 adjusts the charging mode of the charging circuit to a constant current mode; an input end of the proportional regulating unit 52 is connected with a positive output end of the secondary side main circuit 2, and an output end of the proportional regulating unit 52 is connected with the resistance voltage dividing unit 51, and is used for reducing the voltage dividing proportion of the resistance voltage dividing unit 51 when the charging voltage is greater than the preset threshold value.
It can be seen that, in the present application, the proportion adjusting circuit is utilized, and after the charging voltage of the charging circuit is greater than the preset threshold, that is, after the charging circuit enters the constant voltage mode from the constant current mode for the first time, the voltage division proportion of the resistance voltage division unit 51 is reduced, so that the first detection voltage is lower than the first reference voltage and outputs the corresponding first comparison result signal, thereby improving the charging setting voltage, and converting the charging circuit from the constant voltage mode to the constant current mode again. This application has increased the electric quantity when the battery is full of effectively through improving the settlement voltage that charges in stage, has improved the battery utilization ratio, has also avoided directly improving the harm of settlement voltage that charges to the battery life-span simultaneously.
Based on the above, as a preferred embodiment, in the voltage detection circuit of the charging circuit provided in the embodiment of the present application, as shown in fig. 2, the voltage comparison unit 53 includes a first operational amplifier U1 and a first reference voltage source Vref 1; an inverting input terminal of the first operational amplifier U1 is connected to an output terminal of the resistance voltage divider unit 51, and a non-inverting input terminal of the first operational amplifier U1 is connected to a first reference voltage source Vref 1.
Specifically, the inverting input terminal of the first operational amplifier U1 is configured to receive the first detection voltage output by the resistance voltage dividing unit 51, and is configured to compare the first detection voltage with the first reference voltage input by the non-inverting input terminal. If the first detection voltage is lower than the first reference voltage, the first operational amplifier U1 outputs a corresponding first comparison result signal (high level signal).
Based on the above, as a preferred embodiment, the voltage detection circuit of the charging circuit provided in the embodiment of the present application, the resistance voltage dividing unit 51 includes a first resistor R1 and a second resistor R2; a first end of the first resistor R1 is connected with a positive output end of the secondary side main circuit 2; the second end of the first resistor R1 is connected to the first end of the second resistor R2 and serves as the output end of the resistor voltage divider 51; the second terminal of the second resistor R2 is connected to ground.
Specifically, the voltage dividing ratio of the resistance voltage dividing unit 51 at this time is α ═ R2/(R1+ R2). When Vout is used to represent the charging voltage, the first detection voltage V1 at this time is V1 ═ α · Vout.
Based on the above, as a preferred embodiment, the voltage detection circuit of the charging circuit provided in the embodiment of the present application, the proportional regulating unit 52 includes a third resistor R3 and a switching unit; a first end of the third resistor R3 is connected to a first end of the second resistor R2, and a second end of the third resistor R3 is grounded through the switch unit.
Specifically, the embodiment of the present application reduces the voltage division ratio of the resistance voltage division unit 51 by increasing the parallel resistance. The switch unit may be implemented by those skilled in the art using various electronic switch devices, and the present application is not limited thereto. When the charging voltage is greater than the preset threshold, the switching unit is closed, and the third resistor R3 is connected in parallel across the second resistor R2, at which time the voltage division ratio of the resistor voltage division unit 51 becomes α' ═ R2// R3)/(R1+ R2// R3. Since the resistance value of the two resistors connected in parallel is always smaller than that of any one resistor, R2// R3< R2 and therefore α ' < α are necessary, and the first detection voltage obtained at this time is V1 ' ═ α ' · Vout < V1.
As shown in fig. 2, in the voltage detection circuit of the charging circuit provided in the embodiment of the present application, on the basis of the above, as a preferred embodiment, the switch unit includes a MOS transistor, a second operational amplifier U2, a second reference voltage source Vref2, a fourth resistor R4, and a fifth resistor R5;
a first end of a fourth resistor R4 is connected with a positive output end of the secondary side main circuit 2, a second end of the fourth resistor R4 is respectively connected with a first end of a fifth resistor R5 and a first input end of a second operational amplifier U2, and a second end of the fifth resistor R5 is grounded; a second input end of the second operational amplifier U2 is connected with a second reference voltage source Vref 2; the output end of the second operational amplifier U2 is connected with the control end of the MOS tube; the first end of the MOS tube is connected with the second end of the third resistor R3, and the second end of the MOS tube is grounded.
Specifically, in the circuit shown in fig. 2, the core device of the switching unit is a MOS transistor, and whether the MOS transistor is turned on or not is the output of the second operational amplifier U2. The input voltage of the first input end of the second operational amplifier U2 is a second detection voltage V2 output by a fourth resistor R4 and a fifth resistor R5, the second input end of the second operational amplifier U2 is a second reference voltage, and by setting the resistance relationship between the fourth resistor R4 and the fifth resistor R5, when the charging voltage is greater than the preset threshold, the obtained second detection voltage V2 is greater than the second reference voltage, so that the second operational amplifier U2 changes the output to conduct the MOS transistor.
As shown in fig. 2, in the voltage detection circuit of the charging circuit provided in the embodiment of the present application, as a preferred embodiment based on the above, the first input terminal of the second operational amplifier U2 is a non-inverting input terminal, and the second input terminal of the second operational amplifier U2 is an inverting input terminal; the MOS tube is an NMOS tube.
As shown in fig. 2, in the voltage detection circuit of the charging circuit provided in the embodiment of the present application, on the basis of the above contents, as a preferred embodiment, the switch unit further includes a protection capacitor; the first end of the protection capacitor is connected with the control end of the MOS tube, and the second end of the protection capacitor is grounded.
Specifically, the protection capacitor is connected in parallel at two ends of a gate source of the MOS tube and can be used for protecting the MOS tube from being broken down by voltage.
The charging circuit provided by the present application is described below.
As shown in fig. 2, the charging circuit provided in the embodiment of the present application includes a primary side main circuit 1, a secondary side main circuit 2, a mode adjusting circuit 3, a current detecting circuit 4, and any one of the voltage detecting circuits described above;
the primary side main circuit 1 is coupled with the secondary side main circuit 2 through a transformer and is used for transmitting electric energy to the secondary side main circuit 2; the output end of the secondary side main circuit 2 is connected with a battery to be charged and used for inputting rectified and stabilized direct current to the battery to be charged; the current detection circuit 4 is used for detecting the working current of the secondary side main circuit 2; the voltage detection circuit is used for detecting the charging voltage of the secondary side main circuit 2; the mode adjusting circuit 3 is coupled to the control module of the primary side main circuit 1 and is configured to adjust a charging mode of the charging circuit according to the working current and the charging voltage of the secondary side main circuit 2.
As shown in fig. 2, the third diode D3, the inductor L, the fourth diode D4, the capacitor C1 and the output resistor Ro form a secondary main circuit for charging the battery to be charged.
It can be seen that, in the present application, the proportion adjusting circuit is utilized, and after the charging voltage of the charging circuit is greater than the preset threshold, that is, after the charging circuit enters the constant voltage mode from the constant current mode for the first time, the voltage division proportion of the resistance voltage division unit 51 is reduced, so that the first detection voltage is lower than the first reference voltage and outputs the corresponding first comparison result signal, thereby improving the charging setting voltage, and converting the charging circuit from the constant voltage mode to the constant current mode again. This application has increased the electric quantity when the battery is full of effectively through improving the settlement voltage that charges in stage, has improved the battery utilization ratio, has also avoided directly improving the harm of settlement voltage that charges to the battery life-span simultaneously.
On the basis of the above, as a preferred embodiment, the present application provides a charging circuit, in which the current detection circuit 4 includes a sixth resistor R6, a seventh resistor R7, and a third operational amplifier U3;
a first end of a sixth resistor R6 is connected with the negative input end of the secondary side main circuit 2, and a second end of the sixth resistor R6 is connected with the positive phase input end of a third operational amplifier U3; a first end of a seventh resistor R7 is connected with a negative output end of the secondary side main circuit 2, and a second end of the seventh resistor R7 is connected with an inverting input end of a third operational amplifier U3; the output terminal of the third operational amplifier U3 serves as the output terminal of the current detection circuit 4.
On the basis of the above, as a preferred embodiment, the present application provides a charging circuit, in which the mode adjustment circuit 3 includes an eighth resistor R8, an isolation optocoupler OC, a first diode D1, and a second diode D2;
a first end of an eighth resistor R8 is connected with the positive input end of the secondary side main circuit 2, and a second end of an eighth resistor R8 is connected with the positive input end of an isolation optocoupler OC; the negative input end of the isolation optocoupler OC is respectively connected with the anode of the first diode D1 and the anode of the second diode D2, and the output end of the isolation optocoupler OC is coupled with the control module of the primary side main circuit 1; the cathode of the first diode D1 is connected to the output terminal of the current detection unit, and the cathode of the second diode D2 is connected to the output terminal of the voltage detection unit.
Specifically, a first comparison result signal output by the voltage detection circuit affects the conduction state of the isolation optocoupler OC, and then a corresponding signal can be transmitted to the control module of the primary side main circuit 1, the control module increases the output duty ratio, that is, the charging setting voltage is increased, and the working mode of the charging circuit is converted from the constant voltage mode to the constant current mode.
Referring to fig. 3, fig. 3 is a schematic diagram illustrating a charging process of a charging circuit according to an embodiment of the present disclosure. As shown in fig. 3, the period t0-t1 is the initial constant current mode period, and when the charging voltage is close to the initial charging set voltage, the constant voltage mode is entered at the period t1-t 2; at the time t2, the voltage division ratio is adjusted by the voltage detection circuit provided by the application, so that the charging circuit enters the constant current mode again; at time t3, the charging voltage approaches the modified charge set voltage, at which point the battery is nearly fully charged, and the charging circuit again enters constant voltage mode.
The specific implementation of the charging circuit provided in the present application and the voltage detection circuit of the charging circuit described above may be referred to correspondingly, and are not described herein again.
The embodiments are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. The device disclosed by the embodiment corresponds to the method disclosed by the embodiment, so that the description is simple, and the relevant points can be referred to the method part for description.
It is further noted that, throughout this document, relational terms such as "first" and "second" are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Furthermore, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
The technical solutions provided by the present application are described in detail above. The principles and embodiments of the present application are explained herein using specific examples, which are provided only to help understand the method and the core idea of the present application. It should be noted that, for those skilled in the art, without departing from the principle of the present application, several improvements and modifications can be made to the present application, and these improvements and modifications also fall into the protection scope of the present application.
Claims (10)
1. A voltage detection circuit of a charging circuit is characterized by comprising a resistance voltage division unit, a proportion regulation unit and a voltage comparison unit;
the input end of the resistance voltage division unit is connected with the positive output end of a secondary side main circuit of the charging circuit, and the output end of the resistance voltage division unit is connected with the input end of the voltage comparison unit and used for outputting a first detection voltage proportional to the charging voltage of the charging circuit;
the output end of the voltage comparison unit is connected with the input end of a mode adjusting circuit of the charging circuit and used for outputting a first comparison result signal when the first detection voltage is lower than a first reference voltage, and the mode adjusting circuit adjusts the charging mode of the charging circuit into a constant current mode;
the input end of the proportion adjusting unit is connected with the positive output end of the secondary side main circuit, the output end of the proportion adjusting unit is connected with the resistance voltage dividing unit, and the proportion adjusting unit is used for reducing the voltage dividing proportion of the resistance voltage dividing unit when the charging voltage converted into the constant voltage mode is larger than a preset threshold value, so that the first detection voltage is reduced to be smaller than the first reference voltage, and the mode adjusting circuit adjusts the charging mode into the constant current mode again.
2. The voltage detection circuit of claim 1, wherein the voltage comparison unit comprises a first operational amplifier and a first reference voltage source; the inverting input end of the first operational amplifier is connected with the output end of the resistance voltage division unit, and the non-inverting input end of the first operational amplifier is connected with the first reference voltage source.
3. The voltage detection circuit according to claim 1, wherein the resistance voltage division unit includes a first resistance and a second resistance; the first end of the first resistor is connected with the positive output end of the secondary side main circuit; the second end of the first resistor is connected with the first end of the second resistor and serves as the output end of the resistor voltage division unit; and the second end of the second resistor is grounded.
4. The voltage detection circuit of claim 3, wherein the proportional adjustment unit includes a third resistor and a switching unit; the first end of the third resistor is connected with the first end of the second resistor, and the second end of the third resistor is grounded through the switch unit.
5. The voltage detection circuit of claim 4, wherein the switching unit comprises a MOS transistor, a second operational amplifier, a second reference voltage source, a fourth resistor and a fifth resistor;
a first end of the fourth resistor is connected with a positive output end of the secondary side main circuit, a second end of the fourth resistor is respectively connected with a first end of the fifth resistor and a first input end of the second operational amplifier, and a second end of the fifth resistor is grounded; a second input end of the second operational amplifier is connected with the second reference voltage source; the output end of the second operational amplifier is connected with the control end of the MOS tube; and the first end of the MOS tube is connected with the second end of the third resistor, and the second end of the MOS tube is grounded.
6. The voltage detection circuit of claim 5, wherein the first input terminal of the second operational amplifier is a non-inverting input terminal and the second input terminal of the second operational amplifier is an inverting input terminal; the MOS tube is an NMOS tube.
7. The voltage detection circuit according to claim 5 or 6, wherein the switching unit further includes a protection capacitor; the first end of the protection capacitor is connected with the control end of the MOS tube, and the second end of the protection capacitor is grounded.
8. A charging circuit comprising a primary side main circuit, a secondary side main circuit, a mode adjustment circuit, a current detection circuit, and a voltage detection circuit according to any one of claims 1 to 7;
the primary side main circuit is coupled with the secondary side main circuit through a transformer and is used for transmitting electric energy to the secondary side main circuit; the output end of the secondary side main circuit is connected with a battery to be charged and used for inputting rectified and stabilized direct current to the battery to be charged; the current detection circuit is used for detecting the working current of the secondary side main circuit; the voltage detection circuit is used for detecting the charging voltage of the secondary side main circuit; the mode adjusting circuit is coupled with the control module of the primary side main circuit and used for adjusting the charging mode of the charging circuit according to the working current and the charging voltage of the secondary side main circuit.
9. The charging circuit of claim 8, wherein the current detection circuit comprises a sixth resistor, a seventh resistor, and a third op-amp;
a first end of the sixth resistor is connected with a negative input end of the secondary side main circuit, and a second end of the sixth resistor is connected with a positive input end of the third operational amplifier; a first end of the seventh resistor is connected with a negative output end of the secondary side main circuit, and a second end of the seventh resistor is connected with an inverting input end of the third operational amplifier; and the output end of the third operational amplifier is used as the output end of the current detection circuit.
10. The charging circuit of claim 8 or 9, wherein the mode adjustment circuit comprises an eighth resistor, an isolation optocoupler, a first diode, and a second diode;
a first end of the eighth resistor is connected with a positive input end of the secondary side main circuit, and a second end of the eighth resistor is connected with a positive input end of the isolation optocoupler; the negative input end of the isolation optocoupler is respectively connected with the anode of the first diode and the anode of the second diode, and the output end of the isolation optocoupler is coupled with the control module of the primary side main circuit; the cathode of the first diode is connected with the output end of the current detection unit, and the cathode of the second diode is connected with the output end of the voltage detection unit.
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| CN201910184902.8A CN109782049B (en) | 2019-03-12 | 2019-03-12 | Charging circuit and voltage detection circuit thereof |
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| CN201910184902.8A CN109782049B (en) | 2019-03-12 | 2019-03-12 | Charging circuit and voltage detection circuit thereof |
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| CN109782049A CN109782049A (en) | 2019-05-21 |
| CN109782049B true CN109782049B (en) | 2021-05-07 |
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| CN110994726B (en) * | 2019-12-16 | 2022-06-03 | 杭州电子科技大学 | High-voltage isolation hardware protection circuit for preventing capacitor from being overcharged |
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| US6340880B1 (en) * | 1999-11-11 | 2002-01-22 | Mitsumi Electric Co., Ltd. | Method of protecting a chargeable electric cell |
| CN101106334A (en) * | 2006-07-12 | 2008-01-16 | 台达电子工业股份有限公司 | Power converter for providing output power limit and depending on load voltage adjustment |
| CN104348194A (en) * | 2013-07-26 | 2015-02-11 | 无锡华润矽科微电子有限公司 | Electric vehicle charging control circuit and calibration method thereof |
| CN107425718A (en) * | 2017-08-10 | 2017-12-01 | 郑州云海信息技术有限公司 | A kind of DC decompression adjusts circuit structure |
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| US6340880B1 (en) * | 1999-11-11 | 2002-01-22 | Mitsumi Electric Co., Ltd. | Method of protecting a chargeable electric cell |
| CN101106334A (en) * | 2006-07-12 | 2008-01-16 | 台达电子工业股份有限公司 | Power converter for providing output power limit and depending on load voltage adjustment |
| CN104348194A (en) * | 2013-07-26 | 2015-02-11 | 无锡华润矽科微电子有限公司 | Electric vehicle charging control circuit and calibration method thereof |
| CN107425718A (en) * | 2017-08-10 | 2017-12-01 | 郑州云海信息技术有限公司 | A kind of DC decompression adjusts circuit structure |
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