CN116207832B - BOOST charging circuit, charging system and electronic equipment - Google Patents
BOOST charging circuit, charging system and electronic equipment Download PDFInfo
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- CN116207832B CN116207832B CN202310501731.3A CN202310501731A CN116207832B CN 116207832 B CN116207832 B CN 116207832B CN 202310501731 A CN202310501731 A CN 202310501731A CN 116207832 B CN116207832 B CN 116207832B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/007—Regulation of charging or discharging current or voltage
- H02J7/00712—Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters
- H02J7/00714—Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters in response to battery charging or discharging current
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/0029—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits
- H02J7/00304—Overcurrent protection
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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
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
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Abstract
The application is applicable to the technical field of high-voltage DC/DC circuits and provides a BOOST charging circuit, a charging system and electronic equipment. The BOOST charging circuit comprises a feedback unit, an amplifying unit and a power supply unit, wherein the feedback unit is used for outputting a feedback signal, the amplifying unit is used for receiving the feedback signal and a reference signal, and outputting an error amplifying signal according to the feedback signal and the reference signal; the first switching tube is used for adjusting the first current flowing through the first switching tube according to the amplified signal; the current limiting protection unit is used for adjusting the grid voltage of the first switch tube when the first current is larger than the preset current, so that the first current is reduced; a power diode for outputting a first current when turned on; and the charging unit is used for charging according to the first current. The BOOST charging circuit provided by the application can reduce the first current, so that the reverse recovery current of the power diode is reduced, the device damage of the BOOST charging circuit during power supply is avoided, and the reliability of the BOOST charging circuit is improved.
Description
Technical Field
The application belongs to the technical field of high-voltage DC/DC circuits, and particularly relates to a BOOST charging circuit, a charging system and electronic equipment.
Background
The DC/DC upper tube is a PMOS tube, has the defects of large area, large on-resistance and the like, the BOOST charging circuit can solve the problem, the BOOST charging circuit can drive the NMOS, the upper tube is the NMOS, and the DC/DC upper tube has the advantages of small on-resistance, small area, high efficiency and the like, and is widely applied to the fields of mobile communication, electric automobiles, household appliances and the like. As shown in fig. 1, when no-load operation (the fourth switching tube Q4 does not have a switching action for a long time) occurs, a voltage difference (a voltage of the first capacitor C1) between the BS node and the SW node is smaller than a first preset value, the fourth switching tube Q4 is controlled to be turned off, and the fifth switching tube Q5 is controlled to be turned on, at this time, the voltage of the SW node is pulled down, and a current can flow out from VCC, flows through the power diode D1 and the first capacitor C1 to SW, so as to form a charging loop of the first capacitor C1. The first inductor L1 is used for storing energy while the first capacitor C1 is charged.
When the voltage of the first capacitor C1 is greater than or equal to the second preset value, the fourth switching tube Q4 is controlled to be turned on, and the fifth switching tube Q5 is controlled to be turned off, at this time, a reverse induction current generated in the first inductor L1 flows through the fourth switching tube Q4 through the SW node, finally flows into Vin, and the voltage of the SW node is raised, so that the voltage of the BS node is also raised. The power diode D1 is in a reverse off state, and generates a large reverse recovery current to raise the VCC voltage. When VCC is used as a low-voltage power supply to power a charging unit, damage to low-voltage devices may be caused.
Disclosure of Invention
The embodiment of the application provides a BOOST charging circuit, a charging system and electronic equipment, which can solve the problem that the low-voltage device is possibly damaged when the existing charging circuit supplies power to a charging unit.
In a first aspect, an embodiment of the present application provides a BOOST charging circuit, including:
a feedback unit for outputting a feedback signal;
the amplifying unit is electrically connected with the feedback unit and is used for receiving the feedback signal and the reference signal and outputting an amplifying signal according to the feedback signal and the reference signal;
the first switching tube is electrically connected with the amplifying unit and is used for adjusting first current flowing through the first switching tube according to the amplifying signal;
the current limiting protection unit is electrically connected with the first switching tube and is used for adjusting the grid voltage of the first switching tube when the first current is larger than a preset current so as to reduce the first current;
the power diode is electrically connected with the first switching tube or the current limiting protection unit and is used for outputting the first current when being conducted;
and the charging unit is electrically connected with the power diode and is used for charging according to the first current.
In one possible implementation manner of the first aspect, the first switching tube is a PMOS tube, the current limiting protection unit includes a first current collecting unit and a first switching unit, a first end of the first current collecting unit is electrically connected with a first power supply and a first end of the first switching unit, a second end of the first current collecting unit is electrically connected with a control end of the first switching unit and a source electrode of the first switching tube, a second end of the first switching unit is electrically connected with the amplifying unit and a gate electrode of the first switching tube, and a drain electrode of the first switching tube is electrically connected with an anode of the power diode and the feedback unit.
In one possible implementation manner of the first aspect, the first current collecting unit includes a first resistors sequentially connected in series, a first end of the first resistor is electrically connected with the first power supply and a first end of the first switch unit, and a second end of the first resistor is electrically connected with a control end of the first switch unit and a source electrode of the first switch tube, where a is a positive integer, and a is greater than or equal to 1.
In a possible implementation manner of the first aspect, the first switching unit includes a second switching tube, a gate of the second switching tube is electrically connected to the second end of the first current collecting unit and a source of the first switching tube, the source of the second switching tube is electrically connected to the first end of the first current collecting unit and the first power supply, and a drain of the second switching tube is electrically connected to the amplifying unit and the gate of the first switching tube.
In one possible implementation manner of the first aspect, the first switching tube is an NMOS tube, the current limiting protection unit includes a second current collecting unit and a second switching unit, a first end of the second current collecting unit is electrically connected with a control end of the second switching unit and a source electrode of the first switching tube, a second end of the second current collecting unit is electrically connected with a first end of the second switching unit, an anode of the power diode and the feedback unit, and a second end of the second switching unit is electrically connected with the amplifying unit and a gate electrode of the first switching tube.
In one possible implementation manner of the first aspect, the second current collecting unit includes b second resistors sequentially connected in series, a first end of the first second resistor is electrically connected with the control end of the second switching unit and the source electrode of the first switching tube, and a b second end of the second resistor is electrically connected with the first end of the second switching unit, the anode of the power diode and the feedback unit, where b is a positive integer, and b is greater than or equal to 1.
In a possible implementation manner of the first aspect, the second switching unit includes a third switching tube, a gate of the third switching tube is electrically connected to the first end of the second current collecting unit and a source of the first switching tube, a source of the third switching tube is electrically connected to the second end of the second current collecting unit, an anode of the power diode and the feedback unit, and a drain of the third switching tube is electrically connected to the amplifying unit and a gate of the first switching tube.
In a possible implementation manner of the first aspect, the charging unit includes a switching unit, a capacitance unit, and a freewheel unit;
the switch unit is respectively and electrically connected with the capacitor unit and the follow current unit, and the capacitor unit is respectively and electrically connected with the cathode of the power diode and the follow current unit.
In a second aspect, embodiments of the present application provide a charging system, including a BOOST charging circuit as set forth in any one of the first aspects.
In a third aspect, an embodiment of the present application provides an electronic device, including a BOOST charging circuit according to any one of the first aspects.
Compared with the prior art, the embodiment of the application has the beneficial effects that:
the BOOST charging circuit comprises a feedback unit, an amplifying unit, a first switching tube, a power diode, a charging unit and a current limiting protection unit, wherein the feedback unit, the amplifying unit and the first switching tube form an LDO circuit, the output end of the LDO circuit is electrically connected with the power diode, and the power diode is used for supplying power to the charging unit. Compared with the existing BOOST charging circuit, the BOOST charging circuit provided by the application is additionally provided with the current limiting protection unit, and is used for collecting the first current flowing through the first switching tube, and adjusting the grid voltage of the first switching tube when the first current is larger than the preset current, so that the voltage between the grid and the source of the first switching tube is reduced, and the first current flowing through the first switching tube is reduced, namely the current flowing through the power diode is reduced. When the power diode is in a reverse cut-off state, larger reverse recovery current cannot be generated to flow into the output end of the LDO circuit, so that the voltage of the output end of the LDO circuit cannot be raised, the damage of a low-voltage device of the LDO circuit when the LDO circuit supplies power to the charging unit is avoided, and the reliability of the BOOST charging circuit is improved.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required for the embodiments or the description of the prior art will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of a circuit connection of a conventional BOOST charging circuit;
FIG. 2 is a schematic diagram of a circuit connection of another conventional BOOST charging circuit;
FIG. 3 is a schematic block diagram of a BOOST charging circuit provided in an embodiment of the present application;
FIG. 4 is a schematic diagram of a circuit connection of a BOOST charging circuit according to an embodiment of the present disclosure;
fig. 5 is a schematic circuit connection diagram of a BOOST charging circuit according to another embodiment of the present application.
Detailed Description
In the following description, for purposes of explanation and not limitation, specific details are set forth, such as particular system configurations, techniques, etc. in order to provide a thorough understanding of the embodiments of the present application. It will be apparent, however, to one skilled in the art that the present application may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present application with unnecessary detail.
It should be understood that the terms "comprises" and/or "comprising," when used in this specification and the appended claims, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
It should also be understood that the term "and/or" as used in this specification and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes such combinations.
As used in this specification and the appended claims, the term "if" may be interpreted in context as "when …" or "upon" or "in response to determining" or "in response to detecting". Similarly, the phrase "if a determination" or "if a [ described condition or event ] is detected" may be interpreted in the context of meaning "upon determination" or "in response to determination" or "upon detection of a [ described condition or event ]" or "in response to detection of a [ described condition or event ]".
In addition, in the description of the present application and the appended claims, the terms "first," "second," "third," and the like are used merely to distinguish between descriptions and are not to be construed as indicating or implying relative importance.
Reference in the specification to "one embodiment" or "some embodiments" or the like means that a particular feature, structure, or characteristic described in connection with the embodiment is included in one or more embodiments of the application. Thus, appearances of the phrases "in one embodiment," "in some embodiments," "in other embodiments," and the like in the specification are not necessarily all referring to the same embodiment, but mean "one or more but not all embodiments" unless expressly specified otherwise. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless expressly specified otherwise.
As shown in fig. 1, when the existing BOOST charging circuit has no load (the fourth switching tube Q4 does not have a switching action for a long time) and has an excessively long working time or a voltage difference between the BS node and the SW node (the voltage of the first capacitor C1) is smaller than a first preset value, the fourth switching tube Q4 is controlled to be turned off, and the fifth switching tube Q5 is controlled to be turned on, at this time, the voltage of the SW node is pulled down, and a current can flow out from VCC, flows through the power diode D1 and the first capacitor C1 to SW, so as to form a charging loop of the first capacitor C1. The first inductor L1 is used for storing energy while the first capacitor C1 is charged.
When the voltage of the first capacitor C1 is greater than or equal to the second preset value, the fourth switching tube Q4 is controlled to be turned on, and the fifth switching tube Q5 is controlled to be turned off, at this time, a reverse induction current generated in the first inductor L1 flows through the fourth switching tube Q4 through the SW node, finally flows into Vin, and the voltage of the SW node is raised, so that the voltage of the BS node is also raised. The power diode D1 is in a reverse off state, and generates a large reverse recovery current to raise the VCC voltage. When VCC is used as a low-voltage power supply to power a charging unit, damage to low-voltage devices may be caused.
In addition to the PMOS switching transistor in the BOOST charging circuit shown in fig. 1, the switching transistor in the BOOST charging circuit may also be an NMOS switching transistor, as shown in fig. 2. When the voltage of the first capacitor C1 is greater than or equal to the second preset value, the fourth switching tube Q4 is controlled to be turned on, and the fifth switching tube Q5 is controlled to be turned off, at this time, a reverse induction current generated in the first inductor L1 flows through the fourth switching tube Q4 through the SW node, finally flows into Vin, and the voltage of the SW node is raised, so that the voltage of the BS node is also raised. The power diode D1 is in the reverse off state, which generates a larger reverse recovery current to raise the VCC voltage, and also causes the VGS of the switching tube Q1 to exceed 5V to be damaged.
Based on the above problems, the BOOST charging circuit provided in the embodiments of the present application includes a feedback unit, an amplifying unit, a first switching tube, a power diode, a charging unit and a current limiting protection unit, where the feedback unit, the amplifying unit and the first switching tube form an LDO circuit, and an output end of the LDO circuit is electrically connected with the power diode and supplies power to the charging unit through the power diode. Compared with the existing BOOST charging circuit, the BOOST charging circuit provided by the application is additionally provided with the current limiting protection unit, and is used for collecting the first current flowing through the first switching tube, and adjusting the grid voltage of the first switching tube when the first current is larger than the preset current, so that the voltage between the grid and the source of the first switching tube is reduced, and the first current flowing through the first switching tube is reduced, namely the current flowing through the power diode is reduced. When the power diode is in a reverse cut-off state, larger reverse recovery current cannot be generated to flow into the output end of the LDO circuit, so that the voltage of the output end of the LDO circuit cannot be raised, the damage of a low-voltage device of the LDO circuit when the LDO circuit supplies power to the charging unit is avoided, and the reliability of the BOOST charging circuit is improved.
In order to illustrate the technical solutions described in the present application, the following description is made by specific examples.
Fig. 3 shows a schematic block diagram of the BOOST charging circuit 10 according to an embodiment of the present application. Referring to fig. 3, the BOOST charging circuit 10 includes a feedback unit 101, an amplifying unit 102, a first switching tube Q1, a power diode D1, a charging unit 104, and a current limiting protection unit 103.
Specifically, the feedback unit 101 is configured to output a feedback signal; the amplifying unit 102 is electrically connected with the feedback unit 101, and is used for receiving the feedback signal and the reference signal and outputting an amplified signal according to the feedback signal and the reference signal; the first switching tube Q1 is electrically connected with the amplifying unit 102 and is used for adjusting the first current flowing through the first switching tube Q1 according to the amplified signal; the current limiting protection unit 103 is electrically connected with the first switching tube Q1 and is used for adjusting the gate voltage of the first switching tube Q1 when the first current is greater than the preset current so as to reduce the first current; a power diode D1 electrically connected to the first switching tube Q1 or the current limiting protection unit 103, for outputting a first current when turned on; the charging unit 104 is electrically connected to the power diode D1, and is configured to charge according to the first current.
The feedback unit 101, the amplifying unit 102 and the first switching tube Q1 form an LDO circuit, and an output terminal VCC of the LDO circuit is electrically connected with the power diode D1 and supplies power to the charging unit 104 through the power diode D1. Compared to the existing BOOST charging circuit, the BOOST charging circuit 10 provided in the present application is additionally provided with the current limiting protection unit 103, which is configured to collect the first current flowing through the first switching tube Q1, and adjust the gate voltage of the first switching tube Q1 when the first current is greater than the preset current, so that the voltage between the gate and the source of the first switching tube Q1 is reduced, and thus the first current flowing through the first switching tube Q1 is reduced, that is, the current flowing through the power diode D1 is reduced. When the power diode D1 is in the reverse-off state, no large reverse recovery current flows into the output terminal VCC of the LDO circuit, so that the voltage of the output terminal VCC of the LDO circuit is not raised, the low-voltage device damage of the LDO circuit when the charging unit 104 is powered is avoided, and the reliability of the BOOST charging circuit 10 is improved.
It should be noted that, the reference signal received by the amplifying unit 102 may be obtained by the reference voltage unit or may be obtained by a fixed power supply. The reference signal includes a reference voltage value, and the LDO circuit 10 is configured to regulate the input voltage according to the reference voltage value to obtain a stable output voltage, and output the stable output voltage through an output terminal VCC of the LDO circuit 10. That is, the amplified signal is used to control the magnitude of the regulated voltage generated by the output current flowing through the first switching tube Q1, and if the voltage drop voltage obtained by the first switching tube Q1 according to the input voltage and the regulated voltage is not stable, the feedback signal may be output to the amplifying unit 102 through the feedback unit 101. The feedback unit 101 and the amplifying unit 102 constitute a negative feedback loop through which the voltage at the output VCC of the LDO circuit 10 is regulated. The designer can set the reference voltage value according to actual conditions, ensures that the output voltage outputted by the output end VCC of the LDO circuit is stable, and improves the reliability of the BOOST charging circuit.
In one embodiment of the present application, as shown in fig. 4, the first switching tube Q1 is a PMOS tube, and the current limiting protection unit 103 includes a first current collecting unit 1031 and a first switching unit 1032. The first end of the first current collecting unit 1031 is electrically connected to the first power VCC1 and the first end of the first switching unit 1032, respectively, the second end of the first current collecting unit 1031 is electrically connected to the control end of the first switching unit 1032 and the source of the first switching tube Q1, the second end of the first switching unit 1032 is electrically connected to the amplifying unit 102 and the gate of the first switching tube Q1, and the drain of the first switching tube Q1 is electrically connected to the anode of the power diode D1 and the feedback unit 101, respectively.
Specifically, the first current collecting unit 1031 is configured to collect a first current output by the first power VCC1, and convert the first current into a first voltage. The control terminal of the first switching unit 1032 is electrically connected to the second terminal of the first current collecting unit 1031, and is used for switching on or switching off according to the magnitude of the first voltage. When the first current is greater than or equal to the preset current, that is, the first voltage is greater than or equal to the on voltage of the first switching unit 1032, the first switching unit 1032 is in an on state, and when the first current is less than the preset current, the first voltage is less than the on voltage of the first switching unit 1032, the first switching unit 1032 is in an off state.
In one embodiment of the present application, the first current collecting unit 1031 includes a first resistors R1 sequentially connected in series, a first end of the first resistor R1 is electrically connected to the first power VCC1 and a first end of the first switching unit 1032, and a second end of the a first resistor R1 is electrically connected to a control end of the first switching unit 1032 and a source electrode of the first switching tube Q1, where a is a positive integer, and a is greater than or equal to 1.
Specifically, a first resistors R1 are connected in series for limiting current, each first resistor R1 is used for collecting a first current output by the first power VCC1, and obtaining a voltage drop generated by the first current flowing through each first resistor R1, where a sum of the generated a voltage drops is used as a first voltage. The greater the number of first resistors R1 connected in series, the greater the first voltage. The selection of a first resistors R1 in series in turn can ensure accuracy of the first voltage and improve reliability of the first current collecting unit 1031.
The designer may select the resistance and the number of the first resistors R1 connected in series according to the actual condition of the circuit, may select one first resistor R1 with a larger resistance, or may select a plurality of first resistors R1 with smaller resistance to be connected in series. Meanwhile, a designer can select the slide rheostat according to actual conditions, and the resistance value of the resistor is convenient to adjust. The resistance and the number of the first resistor R1 are not limited herein.
In one embodiment of the present application, as shown in fig. 4, the first switching unit 1032 includes a second switching tube Q2, a gate of the second switching tube Q2 is electrically connected to the second end of the first current collecting unit 1031 and a source of the first switching tube Q1, the source of the second switching tube Q2 is electrically connected to the first end of the first current collecting unit 1031 and the first power source VCC1, and a drain of the second switching tube Q2 is electrically connected to the amplifying unit 102 and the gate of the first switching tube Q1.
Specifically, the first resistor R1 is connected in series between the gate and the source of the second switching tube Q2, and the voltage drop generated by the first current flowing through the first resistor R1 is the voltage between the source and the gate of the second switching tube Q2. When the first current is greater than or equal to the preset current, that is, the voltage between the source and the gate of the second switching tube Q2 is greater than or equal to the turn-on voltage of the second switching tube Q2, the second switching tube Q2 is in a turned-on state. At this time, the source and the drain of the second switching tube Q2 are turned on, so that the gate of the first switching tube Q1 is raised, the voltage difference between the source and the gate of the first switching tube Q1 is reduced, and the first current flowing through the first switching tube Q1 is reduced, so that the current output by the output end VCC of the LDO circuit is reduced, which can avoid damaging the low-voltage device when the LDO circuit supplies power to the charging unit 104, and improve the reliability of the BOOST charging circuit 10.
For example, the designer may select the type of the second switching tube Q2, for example, select the second switching tube Q2 as a PMOS tube.
In one embodiment of the present application, as shown in fig. 4, the amplifying unit 102 includes an amplifier U1, a positive input terminal of the amplifier U1 is electrically connected to the reference voltage unit, a negative input terminal of the amplifier U1 is electrically connected to the feedback unit 101, and an output terminal of the amplifier U1 is electrically connected to a gate of the first switching tube Q1.
Specifically, the amplifier U1 is configured to receive the reference signal output by the reference voltage unit and the feedback signal output by the feedback unit 101, and output an amplified signal to the gate of the first switching tube Q1 according to the reference signal and the feedback signal. The amplifier U1 is further configured to receive the reference voltage output by the reference voltage unit and the feedback voltage output by the feedback unit 101, and amplify a difference between the reference voltage and the feedback voltage to obtain a driving voltage of the first switching tube Q1, so as to control a magnitude of the regulated voltage generated by the first current flowing through the first switching tube Q1.
In one embodiment of the present application, as shown in fig. 4, the feedback unit 101 includes a third resistor R3 and a fourth resistor R4, where a first end of the third resistor R3 is electrically connected to the anode of the power diode D1, a second end of the third resistor R3 is electrically connected to a first end of the fourth resistor R4 and a negative input end of the amplifier U1, respectively, and a second end of the fourth resistor R4 is grounded.
Specifically, the feedback unit 101 divides the voltage at the output terminal VCC of the LDO circuit through the third resistor R3 and the fourth resistor R4 connected in series, samples the voltage at the output terminal VCC of the LDO circuit in a manner of dividing the voltage by the third resistor R3 and the fourth resistor R4 connected in series, and outputs a feedback signal to the negative input terminal of the amplifier U1 according to the voltage at the output terminal VCC of the LDO circuit.
In one embodiment of the present application, as shown in fig. 5, the first switching transistor Q1 is an NMOS transistor, and the current limiting protection unit 103 includes a second current collecting unit 1033 and a second switching unit 1034. The first end of the second current collecting unit 1033 is electrically connected to the control end of the second switching unit 1034 and the source electrode of the first switching tube Q1, respectively, the second end of the second current collecting unit 1033 is electrically connected to the first end of the second switching unit 1034, the anode of the power diode D1 and the feedback unit 101, respectively, and the second end of the second switching unit 1034 is electrically connected to the amplifying unit 102 and the gate electrode of the first switching tube Q1, respectively.
Specifically, the second current collecting unit 1033 is configured to collect a first current output by the first power VCC1, and convert the first current into a first voltage. The control terminal of the second switching unit 1034 is electrically connected to the first terminal of the second current collecting unit 1033, and is used for switching on or switching off according to the magnitude of the first voltage. The second switching unit 1034 is in an on state when the first current is greater than or equal to a preset current, that is, the first voltage is greater than or equal to the on voltage of the second switching unit 1034, and the second switching unit 1034 is in an off state when the first voltage is less than the on voltage of the second switching unit 1034 when the first current is less than the preset current.
In one embodiment of the present application, the second current collecting unit 1033 includes b second resistors R2 sequentially connected in series, a first end of the first second resistor R2 is electrically connected with the control end of the second switching unit 1034 and the source electrode of the first switching tube Q1, and a second end of the b second resistor R2 is electrically connected with the first end of the second switching unit 1034, the anode of the power diode D1 and the feedback unit 101, where b is a positive integer, and b is greater than or equal to 1.
Specifically, b second resistors R2 are connected in series for limiting current, each second resistor R2 is used for collecting a first current output by the first power VCC1, and obtaining a voltage drop generated by the first current flowing through each second resistor R2, where a sum of the generated b voltage drops is used as the first voltage. The greater the number of second resistors R2 connected in series, the greater the first voltage. The b second resistors R2 are selected to be sequentially connected in series, so that accuracy of the first voltage can be ensured, and reliability of the second current collecting unit 1033 can be improved.
The designer may select the resistance and the number of the second resistors R2 connected in series according to the actual condition of the circuit, and may select one second resistor R2 with a larger resistance, or may select a plurality of second resistors R2 with smaller resistance to be connected in series. Meanwhile, a designer can select the slide rheostat according to actual conditions, and the resistance value of the resistor is convenient to adjust. The resistance and the number of the second resistors R2 are not limited herein.
In one embodiment of the present application, as shown in fig. 5, the second switching unit 1034 includes a third switching tube Q3, a gate of the third switching tube Q3 is electrically connected to a first end of the second current collecting unit 1033 and a source of the first switching tube Q1, the source of the third switching tube Q3 is electrically connected to a second end of the second current collecting unit 1033, an anode of the power diode D1 and the feedback unit 101, and a drain of the third switching tube Q3 is electrically connected to the amplifying unit 102 and the gate of the first switching tube Q1.
Specifically, the second resistor R2 is connected in series between the gate and the source of the third switching tube Q3, and the voltage drop generated by the first current flowing through the second resistor R2 is the voltage between the gate and the source of the third switching tube Q3. When the first current is greater than or equal to the preset current, that is, the voltage between the gate and the source of the third switching tube Q3 is greater than or equal to the turn-on voltage of the third switching tube Q3, the third switching tube Q3 is in a turned-on state. At this time, the gate and the source of the third switching tube Q3 are turned on, so that the gate of the first switching tube Q1 is pulled down, the voltage difference between the gate and the source of the first switching tube Q1 is reduced, and the first current flowing through the first switching tube Q1 is reduced, so that the current output by the output end VCC of the LDO circuit is reduced, which can avoid damaging the electronic device when the LDO circuit supplies power to the charging unit 104, and improve the reliability of the BOOST charging circuit 10.
For example, the designer may select the type of the third switching transistor Q3, for example, select the third switching transistor Q3 as an NMOS transistor.
In one embodiment of the present application, as shown in fig. 5, the charging unit 104 includes a switching unit 1041, a capacitance unit 1042, and a freewheel unit 1043. The switching unit 1041 is electrically connected to the capacitor unit 1042 and the freewheel unit 1043, respectively, and the capacitor unit 1042 is electrically connected to the cathode of the power diode D1 and the freewheel unit 1043, respectively.
Specifically, the switching unit 1041 is turned on or off according to the control signal, and the switching unit 1041 may provide a charging loop for the capacitor unit 1042. The capacitor unit 1042 is used for storing energy, and the freewheel unit 1043 is used for forming a freewheel loop for continuously supplying power to the load 20.
It should be noted that the switching unit 1041 includes a fourth switching tube Q4 and a fifth switching tube Q5, a drain electrode of the fourth switching tube Q4 is configured to receive the input voltage signal Vin, a gate electrode of the fourth switching tube Q4 is configured to receive the first driving signal and be turned on or off according to the first driving signal, a drain electrode of the fourth switching tube Q4 is electrically connected to a drain electrode of the fifth switching tube Q5, and a drain connection point of the drain electrode of the fourth switching tube Q4 and the drain electrode of the fifth switching tube Q5 is denoted as a SW node. The gate of the fifth switching tube Q5 is configured to receive the second driving signal, and is turned on or off according to the second driving signal, and the source of the fifth switching tube Q5 is grounded.
The first driver U2 is configured to output a first driving signal to the gate of the fourth switching transistor Q4 according to the PWM control signal, and the second driver U3 is configured to output a second driving signal to the gate of the fifth switching transistor Q5 according to the Lcontr control signal.
The capacitor unit 1042 includes a first capacitor C1, a first end of the first capacitor C1 is electrically connected to the cathode of the power diode D1, and a second end of the first capacitor C1 is electrically connected to the freewheel unit 1043, the drain of the fourth switching tube Q4, and the drain of the fifth switching tube Q5, respectively.
The freewheel unit 1043 includes a first inductor L1, a second capacitor C2, and a second diode D2, where a first end of the first inductor L1 is electrically connected to a second end of the first capacitor C1 and a cathode of the second diode D2, and a second end of the first inductor L1 is electrically connected to a first end of the second capacitor C2, and a second end of the second capacitor C2 and an anode of the second diode D2 are electrically connected to ground.
Specifically, when the LDO circuit charges the first capacitor C1 (the voltage of the first capacitor C1 is smaller than the first preset value), the fourth switching tube Q4 is controlled to be turned off, and the fifth switching tube Q5 is controlled to be turned on, at this time, the voltage of the SW node is pulled down, and the current can flow out from the output terminal VCC of the LDO circuit, flows through the power diode D1 and the first capacitor C1 to SW, so as to form a charging loop of the first capacitor C1. During the process of charging the first capacitor C1 by the LDO circuit, the LDO circuit also supplies power to the load 20 through the first inductor L1, and at this time, the first inductor L1 is used for storing energy.
When the voltage of the first capacitor C1 is greater than or equal to the second preset value, the fourth switching tube Q4 is controlled to be turned on, and the fifth switching tube Q5 is controlled to be turned off, and at this time, the first inductor L1, the load 20 and the second diode D2 form a freewheeling circuit, so that power can be continuously supplied to the load 20.
For example, the designer may choose the first preset value and the second preset value according to the actual situation, for example, choose the first preset value to be 2.7V, and choose the second preset value to be 2.9V.
In order to clearly explain the operation principle of the BOOST charging circuit 10, the following description will be made in detail with reference to fig. 5.
For example, when no-load (the fourth switching tube Q4 has no switching action for a long time) is generated for too long or when the voltage difference between the BS node and the SW node (the voltage of the first capacitor C1) is smaller than the first preset value (2.7V), the fourth switching tube Q4 is controlled to be turned off, and the fifth switching tube Q5 is controlled to be turned on, at this time, the voltage of the SW node is pulled down, and the first current may flow from VCC, flow through the power diode D1, and the first capacitor C1 flows to SW, so as to form a charging loop of the first capacitor C1. According to the embodiment of the application, the current limiting protection unit 103 is additionally arranged, so that the first current can be reduced, the charging current of the first capacitor C1 is reduced, and the situation that when the voltage of the first capacitor C1 is larger than or equal to the second preset value (2.9V), the power diode D1 generates larger reverse recovery current to raise the VCC voltage can be avoided, and the reliability of the BOOST charging circuit 10 is improved.
It should be noted that, the charging unit 104 is a DC/DC conversion circuit commonly used in the prior art, and the circuit belongs to the prior art, and the working principle of the DC/DC conversion circuit is not repeated here.
The application also discloses a charging system, including foretell BOOST charging circuit, can avoid the BOOST charging circuit in the high voltage DC/DC to damage at the low-voltage device when supplying power, improve BOOST charging circuit's reliability.
The application also discloses electronic equipment, including foretell BOOST charging circuit, can avoid the BOOST charging circuit in the high voltage DC/DC to damage at the low-voltage device when supplying power, improve BOOST charging circuit's reliability.
Since the processing and functions implemented by the charging system and the electronic device in this embodiment basically correspond to the embodiments, principles and examples of the BOOST charging circuit, the description of this embodiment is not exhaustive, and reference may be made to the related descriptions in the foregoing embodiments, which are not repeated herein.
The above embodiments are only for illustrating the technical solution of the present application, and are not limiting; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present application, and are intended to be included in the scope of the present application.
Claims (10)
1. A BOOST charging circuit, comprising:
a feedback unit for outputting a feedback signal;
the amplifying unit is electrically connected with the feedback unit and is used for receiving the feedback signal and the reference signal and outputting an amplifying signal according to the feedback signal and the reference signal;
the first switching tube is electrically connected with the amplifying unit and is used for adjusting first current flowing through the first switching tube according to the amplifying signal;
the current limiting protection unit is electrically connected with the first switching tube and is used for adjusting the grid voltage of the first switching tube when the first current is larger than a preset current so as to reduce the first current;
the power diode is electrically connected with the first switching tube or the current limiting protection unit and is used for outputting the first current when being conducted;
and the charging unit is electrically connected with the power diode and is used for charging according to the first current.
2. The BOOST charging circuit of claim 1, wherein the first switching tube is a PMOS tube, the current limiting protection unit comprises a first current collecting unit and a first switching unit, a first end of the first current collecting unit is electrically connected with a first power supply and a first end of the first switching unit respectively, a second end of the first current collecting unit is electrically connected with a control end of the first switching unit and a source electrode of the first switching tube respectively, a second end of the first switching unit is electrically connected with the amplifying unit and a gate electrode of the first switching tube respectively, and a drain electrode of the first switching tube is electrically connected with an anode of the power diode and the feedback unit respectively.
3. The BOOST charging circuit of claim 2, wherein the first current collecting unit comprises a plurality of first resistors sequentially connected in series, a first end of a first resistor is electrically connected with the first power supply and a first end of the first switching unit respectively, and a second end of a first resistor is electrically connected with a control end of the first switching unit and a source electrode of the first switching tube respectively, wherein a is a positive integer, and a is not less than 1.
4. The BOOST charging circuit of claim 2, wherein the first switching unit comprises a second switching tube, a gate of the second switching tube is electrically connected to the second end of the first current collecting unit and a source of the first switching tube, the source of the second switching tube is electrically connected to the first end of the first current collecting unit and the first power supply, and a drain of the second switching tube is electrically connected to the amplifying unit and the gate of the first switching tube.
5. The BOOST charging circuit of claim 1, wherein the first switching tube is an NMOS tube, the current limiting protection unit comprises a second current collecting unit and a second switching unit, a first end of the second current collecting unit is electrically connected with a control end of the second switching unit and a source electrode of the first switching tube, a second end of the second current collecting unit is electrically connected with a first end of the second switching unit, an anode of the power diode and the feedback unit, and a second end of the second switching unit is electrically connected with gates of the amplifying unit and the first switching tube.
6. The BOOST charging circuit of claim 5, wherein the second current collecting unit comprises b second resistors sequentially connected in series, a first end of the first second resistor is electrically connected with the control end of the second switching unit and the source electrode of the first switching tube respectively, and a second end of the b second resistor is electrically connected with the first end of the second switching unit, the anode of the power diode and the feedback unit respectively, wherein b is a positive integer, and b is greater than or equal to 1.
7. The BOOST charging circuit of claim 5, wherein the second switching unit comprises a third switching tube, a gate of the third switching tube is electrically connected to the first end of the second current collecting unit and a source of the first switching tube, a source of the third switching tube is electrically connected to the second end of the second current collecting unit, an anode of the power diode and the feedback unit, and a drain of the third switching tube is electrically connected to the amplifying unit and a gate of the first switching tube.
8. The BOOST charging circuit of claim 1, wherein the charging unit comprises a switching unit, a capacitance unit, and a freewheel unit;
the switch unit is respectively and electrically connected with the capacitor unit and the follow current unit, and the capacitor unit is respectively and electrically connected with the cathode of the power diode and the follow current unit.
9. A charging system comprising a BOOST charging circuit according to any one of claims 1 to 8.
10. An electronic device comprising a BOOST charging circuit according to any one of claims 1-8.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202310501731.3A CN116207832B (en) | 2023-05-06 | 2023-05-06 | BOOST charging circuit, charging system and electronic equipment |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202310501731.3A CN116207832B (en) | 2023-05-06 | 2023-05-06 | BOOST charging circuit, charging system and electronic equipment |
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| CN116207832A (en) | 2023-06-02 |
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