CN117595662A - Charging circuit and DCDC switching power supply - Google Patents
Charging circuit and DCDC switching power supply Download PDFInfo
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- CN117595662A CN117595662A CN202311590131.5A CN202311590131A CN117595662A CN 117595662 A CN117595662 A CN 117595662A CN 202311590131 A CN202311590131 A CN 202311590131A CN 117595662 A CN117595662 A CN 117595662A
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- switching tube
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- control circuit
- resistor
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- 238000007600 charging Methods 0.000 title claims abstract description 33
- HEZMWWAKWCSUCB-PHDIDXHHSA-N (3R,4R)-3,4-dihydroxycyclohexa-1,5-diene-1-carboxylic acid Chemical compound O[C@@H]1C=CC(C(O)=O)=C[C@H]1O HEZMWWAKWCSUCB-PHDIDXHHSA-N 0.000 title claims abstract description 23
- 239000003990 capacitor Substances 0.000 claims abstract description 25
- 238000010277 constant-current charging Methods 0.000 abstract description 4
- 230000000087 stabilizing effect Effects 0.000 description 5
- 238000010586 diagram Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000003071 parasitic effect Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 1
Abstract
The invention discloses a charging circuit and a DCDC switching power supply, which are used for the DCDC switching power supply, wherein the DCDC switching power supply comprises a load switching tube and a load capacitor, a first end of the load switching tube is connected with the load capacitor to form an output end, a second end of the load switching tube is used for receiving input voltage, and the charging circuit comprises: the first control circuit, the second control circuit and the third control circuit. According to the charging circuit and the DCDC switching power supply, when the input voltage slowly rises, the first control circuit controls the load switching tube to perform constant-current charging on the output end, when the input voltage rapidly rises, the third control circuit controls the second control circuit to rapidly open, the opened second control circuit rapidly controls the control end of the load switching tube to perform rapid auxiliary charging on the output end, and the first control circuit controls the load switching tube to perform constant-current charging on the output end until the second control circuit is closed.
Description
Technical Field
The present invention relates to the field of integrated circuits, and more particularly, to a charging circuit and a DCDC switching power supply.
Background
In the DCDC switching power supply, a load switching tube is used for connection between a front-stage output terminal and a final output terminal of the DCDC switching power supply. When the load switching tube works, the output end of the load switching tube needs to be charged to a certain voltage in a constant current mode in the starting stage, and then the subsequent switching action is started.
The information disclosed in this background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person of ordinary skill in the art.
Disclosure of Invention
The invention aims to provide a charging circuit and a DCDC switching power supply, which can charge the output end of a load switching tube to a certain voltage at the starting stage.
To achieve the above object, an embodiment of the present invention provides a charging circuit for a DCDC switching power supply, the DCDC switching power supply including a load switching tube and a load capacitor, a first end of the load switching tube being connected to the load capacitor to form an output end, a second end of the load switching tube being used for receiving an input voltage, the charging circuit comprising:
the first control circuit is connected with the input voltage, the reference voltage and the control end of the load switching tube and is used for controlling the on-off of the load switching tube based on the input voltage and the reference voltage;
the second control circuit is connected with the control end of the load switching tube and is used for controlling the voltage of the control end of the load switching tube by opening and closing the second control circuit; and
and the third control circuit is connected with the input voltage and the second control circuit and is used for controlling the on and off of the second control circuit based on the input voltage.
In one or more embodiments of the present invention, the first control circuit includes a first switching tube, a first resistor, and an amplifier, wherein a first end of the first resistor is connected to a first input terminal of the amplifier, a second end of the first resistor is connected to a ground voltage, a second input terminal of the amplifier is used for receiving a reference voltage, an output terminal of the amplifier is connected to a control terminal of a load switching tube, a first end of the first switching tube is connected to a first input terminal of the amplifier, a control terminal of the first switching tube is connected to an output terminal of the amplifier, and a second end of the first switching tube is used for receiving the input voltage.
In one or more embodiments of the present invention, the second control circuit includes a second switching tube and a fifth resistor, a first end of the fifth resistor is connected to a control end of the second switching tube, a second end of the fifth resistor is connected to a third control circuit, a first end of the second switching tube is connected to a control end of the load switching tube, and a second end of the second switching tube is connected to a ground voltage.
In one or more embodiments of the present invention, the second control circuit further includes a first voltage regulator tube, or a first voltage regulator tube, where a cathode of the first voltage regulator tube is connected to a control terminal of the second switching tube, an anode of the first voltage regulator tube is connected to a ground voltage, a first terminal of the third resistor is used to receive an input voltage, and a second terminal of the third resistor is connected to a first terminal of the second switching tube.
In one or more embodiments of the present invention, the second control circuit further includes a second resistor, a first end of the second resistor is connected to a control end of the second switching tube, and a second end of the second resistor is connected to a ground voltage.
In one or more embodiments of the present invention, the third control circuit includes a third switching tube, a second end of which is used for receiving an input voltage, and a control unit connected to the input voltage and a control end of the third switching tube to control the opening and closing of the third switching tube, and a first end of which is connected to the second control circuit.
In one or more embodiments of the present invention, the control unit includes a fourth resistor and a first capacitor, wherein a first end of the fourth resistor is used for receiving an input voltage, a second end of the fourth resistor is connected to a control end of the third switching tube, a first end of the first capacitor is connected to a control end of the third switching tube, and a second end of the first capacitor is connected to a control end of the load switching tube.
In one or more embodiments of the present invention, the third control circuit further includes a fifth resistor, a first end of the fifth resistor is connected to the first end of the third switching tube, and a second end of the fifth resistor is connected to the second control circuit.
In one or more embodiments of the present invention, the third control circuit further includes a second voltage regulator tube, a cathode of the second voltage regulator tube is connected to the first end of the third switching tube, and an anode of the second voltage regulator tube is connected to the control unit and the second control circuit.
The invention also discloses a DCDC switching power supply, which comprises a load switching tube, a load capacitor and the charging circuit, wherein the first end of the load switching tube is connected with the load capacitor, the second end of the load switching tube is used for receiving input voltage, and the control end of the load switching tube is connected with the charging circuit.
Compared with the prior art, according to the charging circuit and the DCDC switching power supply provided by the embodiment of the invention, when the input voltage slowly rises, the first control circuit controls the load switching tube to perform constant current charging on the output end, when the input voltage rapidly rises, the third control circuit controls the second control circuit to rapidly open, the second control circuit rapidly controls the control end of the load switching tube to rapidly assist in charging on the output end, and the first control circuit controls the load switching tube to perform constant current charging on the output end until the second control circuit is closed.
Drawings
Fig. 1 is a schematic circuit diagram of a charging circuit according to an embodiment of the present invention.
Fig. 2 is a waveform diagram of an output voltage and an input voltage of a charging circuit according to an embodiment of the invention.
Detailed Description
Specific embodiments of the invention will be described in detail below with reference to the drawings, but it should be understood that the scope of the invention is not limited to the specific embodiments.
Throughout the specification and claims, unless explicitly stated otherwise, the term "comprise" or variations thereof such as "comprises" or "comprising", etc. will be understood to include the stated element or component without excluding other elements or components.
The term "coupled" or "connected" in this specification includes both direct and indirect connections. An indirect connection is a connection made through an intermediary, such as an electrically conductive medium, which may have parasitic inductance or parasitic capacitance; indirect connections may also include connections through other active or passive devices, such as through circuits or components such as switches, follower circuits, and the like, that accomplish the same or similar functional objectives. Furthermore, in the present invention, terms such as "first," "second," and the like, are used primarily to distinguish one technical feature from another, and do not necessarily require or imply a certain actual relationship, number or order between the technical features.
As shown in fig. 1, a charging circuit is connected to a DCDC switching power supply, where the DCDC switching power supply includes a load switching tube M and a load capacitor C, the load switching tube M is a P-channel MOS tube, a first end of the load switching tube M is a drain electrode, a second end of the load switching tube M is a source electrode, and a control end of the load switching tube M is a gate electrode. The first end of the load switch tube M is connected with the first end of the load capacitor C to form an output end VO, the second end of the load capacitor C is connected with the ground voltage, and the second end of the load switch tube M is used for receiving the input voltage VD.
The charging circuit includes: the first control circuit 10, the second control circuit 20 and the third control circuit 30. The first control circuit 10 is connected to the input voltage VD, the reference voltage VREF, and the control terminal of the load switching tube M, and the first control circuit 10 is configured to control the on and off of the load switching tube M based on the input voltage VD and the reference voltage VREF. The second control circuit 20 is connected to the control terminal of the load switching tube M, and the second control circuit 20 is configured to control the voltage of the control terminal of the load switching tube M by turning on and off itself. The third control circuit 30 is connected to the input voltage VD and the second control circuit 20, and the third control circuit 30 is configured to control on and off of the second control circuit 20 based on the input voltage VD.
The first control circuit 10 includes a first switching tube M1, a first resistor R1, and an amplifier A1. The first switching tube M1 is a P-channel MOS tube, the first end of the first switching tube M1 is a drain electrode, the second end of the first switching tube M1 is a source electrode, and the control end of the first switching tube M1 is a grid electrode; the first input of the amplifier A1 is a positive input and the second input of the amplifier A1 is a negative input. The first end of the first resistor R1 is connected with the first input end of the amplifier A1, the second end of the first resistor R1 is connected with the ground voltage GND, the second input end of the amplifier A1 is used for receiving the reference voltage VREF, the output end of the amplifier A1 is connected with the control end of the load switching tube M, the first end of the first switching tube M1 is connected with the first input end of the amplifier A1, the control end of the first switching tube M1 is connected with the output end of the amplifier A1, and the second end of the first switching tube M1 is used for receiving the input voltage VD.
In other embodiments, the first input end of the amplifier A1 may be a negative input end, the second input end of the amplifier A1 may be a positive input end, the first switching tube M1 may be an N-channel MOS tube, the first end of the first switching tube M1 is a drain electrode, the second end of the first switching tube M1 is a source electrode, and the control end of the first switching tube M1 is a gate electrode.
As shown in fig. 1, the second control circuit 20 includes a first voltage regulator tube Z1, a second resistor R2, a second switching tube M2, a third resistor R3, and a fifth resistor R5. The second switching tube M2 is an N-channel MOS tube, the first end of the second switching tube M2 is a drain electrode, the second end of the second switching tube M2 is a source electrode, and the control end of the second switching tube M2 is a grid electrode. The first end of the second resistor R2 is connected to the control end of the second switching tube M2, and the second end of the second resistor R2 is connected to the ground voltage GND. The first end of the second switching tube M2 is connected with the control end of the load switching tube M, and the second end of the second switching tube M2 is connected with the ground voltage GND. The first end of the third resistor R3 is configured to receive the input voltage VD, and the second end of the third resistor R3 is connected to the first end of the second switching tube M2. The cathode of the first voltage stabilizing tube Z1 is connected with the control end of the second switching tube M2, and the anode of the first voltage stabilizing tube Z1 is connected with the ground voltage GND. In other embodiments, the second switching transistor M2 may be a P-channel MOS transistor.
As shown in fig. 1, the third control circuit 30 includes a fifth resistor R5, a third switching tube M3, and a control unit. The third switching tube M3 is a P-channel MOS tube, the first end of the third switching tube M3 is a drain electrode, the second end of the third switching tube M3 is a source electrode, and the control end of the third switching tube M3 is a grid electrode. The second end of the third switching tube M3 is configured to receive the input voltage VD, and the control unit is connected to the input voltage VD and the control end of the third switching tube M3 to control the third switching tube M3 to be turned on and off, and the first end of the third switching tube M3 is connected to the first end of the fifth resistor R5. The second terminal of the fifth resistor R5 is connected to the control terminal of the second switching tube M2 of the second control circuit 20.
The control unit comprises a fourth resistor R4 and a first capacitor C1. The first end of the fourth resistor R4 is configured to receive the input voltage VD, and the second end of the fourth resistor R4 is connected to the control end of the third switching tube M3. The first end of the first capacitor C1 is connected with the control end of the third switching tube M3, and the second end of the first capacitor C1 is connected with the control end of the load switching tube M, the second end of the third resistor R3 and the first end of the second MOS tube M2.
As can be seen from the above description, the fifth resistor R5 is a resistor shared by the second control circuit 20 and the third control circuit 30, the fifth resistor R5 is a current limiting resistor, and when the third MOS transistor M3 is turned on, the current on the third MOS transistor M3 is limited not to exceed VD/(r5+r2), and the voltage between the second end of the third MOS transistor M3 and the first end of the third MOS transistor M3 is limited. In addition, the voltage between the control end of the second MOS transistor M2 and the second end of the second MOS transistor M2 can be maintained at a proper value by the voltage division between the fifth resistor R5 and the second resistor R2, so as to cooperate with the first voltage stabilizing transistor Z1 to protect the second MOS transistor M2.
In an embodiment, the input voltage VD is an input of the load switching tube M, the output end VO is an output of the load switching tube M, the first voltage stabilizing tube Z1 is used for protecting the second MOS tube M2, and the second voltage stabilizing tube Z2 is used for protecting a voltage between the control end and the second end of the first MOS tube M1 and a voltage between the control end and the second end of the third MOS tube M3.
As shown in fig. 2 (a), when the input voltage VD slowly rises, the time for the input voltage VD to rise to the target value is far greater than R4 by C1 time constant, the voltage at the control end of the third MOS transistor M3 changes along with the input voltage VD, the third MOS transistor M3 is turned off at this time, the voltage at the control end of the second MOS transistor M2 is less than the turn-on voltage VTH thereof, the second MOS transistor M2 is also turned off, and neither the second control circuit 20 nor the third control circuit 30 operates. The ratio N of the width-length ratio of the load switch tube M to the first MOS tube M1 is 1, the current on the first MOS tube M1 is VREF/R1, the output end VO is charged by the constant current N by the amplifier A1 until the voltage of the output end VO is about the input voltage VD.
As shown in fig. 2 (b), if the output voltage of the DCDC power supply voltage (i.e., the input voltage VD) is stepped due to the rapid power-up of the power supply voltage of the DCDC power supply, the time for the input voltage VD to rise to the target value is very fast and is far smaller than R4 x C1 time constant, the voltage of the control end of the third MOS transistor M3 needs to react to keep up with the input voltage VD, at this time, the voltage of the control end of the third MOS transistor M3 is stabilized by the first capacitor C1, the voltage of the control end of the third MOS transistor M3 and the input voltage VD are pulled apart to cause the third MOS transistor M3 to operate, the current of the third MOS transistor M3 flows through the second resistor R2 to raise the voltage of the control end of the second MOS transistor M2, the pull-down capability of the second MOS transistor M2 is larger than the output capability of the amplifier A1, the current on the load switch transistor M is not constant, at this time, but the maximum current capability is applied to the output end of the third MOS transistor M, and the voltage is pulled up to the output voltage VO is turned off from the first transistor V1 to the control end of the first transistor VO 1 until the voltage VO is raised to the first voltage VO 1, and the load voltage VO is turned off.
In other embodiments, the invention also discloses a DCDC switching power supply, which comprises a load switching tube M, a load capacitor C and the charging circuit, wherein the first end of the load switching tube M is connected with the load capacitor C, the second end of the load switching tube M is used for receiving the input voltage VD, and the control end of the load switching tube M is connected with the charging circuit.
The invention also discloses a chip comprising the charging circuit or the DCDC switching power supply.
The foregoing descriptions of specific exemplary embodiments of the present invention are presented for purposes of illustration and description. It is not intended to limit the invention to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teachings or may be acquired from other forms, structures, arrangements, proportions, and with other components, materials and parts. The exemplary embodiments were chosen and described in order to explain the principles of the invention and its practical application to thereby enable others skilled in the art to make and utilize the invention in various exemplary embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims and their equivalents.
Claims (10)
1. A charging circuit for a DCDC switching power supply, the DCDC switching power supply including a load switching tube and a load capacitor, a first end of the load switching tube being connected to the load capacitor to form an output, a second end of the load switching tube being configured to receive an input voltage, the charging circuit comprising:
the first control circuit is connected with the input voltage, the reference voltage and the control end of the load switching tube and is used for controlling the on-off of the load switching tube based on the input voltage and the reference voltage;
the second control circuit is connected with the control end of the load switching tube and is used for controlling the voltage of the control end of the load switching tube by opening and closing the second control circuit; and
and the third control circuit is connected with the input voltage and the second control circuit and is used for controlling the on and off of the second control circuit based on the input voltage.
2. The charging circuit of claim 1, wherein the first control circuit comprises a first switching tube, a first resistor and an amplifier, wherein a first end of the first resistor is connected to a first input terminal of the amplifier, a second end of the first resistor is connected to a ground voltage, a second input terminal of the amplifier is used for receiving a reference voltage, an output terminal of the amplifier is connected to a control terminal of a load switching tube, a first end of the first switching tube is connected to the first input terminal of the amplifier, a control terminal of the first switching tube is connected to an output terminal of the amplifier, and a second end of the first switching tube is used for receiving the input voltage.
3. The charging circuit of claim 1, wherein the second control circuit comprises a second switching tube and a fifth resistor, a first end of the fifth resistor is connected to a control end of the second switching tube, a second end of the fifth resistor is connected to a third control circuit, a first end of the second switching tube is connected to a control end of the load switching tube, and a second end of the second switching tube is connected to a ground voltage.
4. The charging circuit of claim 3, wherein the second control circuit further comprises a first voltage regulator tube, or a first voltage regulator tube, wherein a cathode of the first voltage regulator tube is connected to a control terminal of the second switching tube, an anode of the first voltage regulator tube is connected to a ground voltage, a first terminal of the third resistor is configured to receive an input voltage, and a second terminal of the third resistor is connected to a first terminal of the second switching tube.
5. The charging circuit of claim 3, wherein the second control circuit further comprises a second resistor, a first terminal of the second resistor being coupled to a control terminal of the second switching tube, and a second terminal of the second resistor being coupled to a ground voltage.
6. The charging circuit of claim 1, wherein the third control circuit comprises a third switching tube and a control unit, the second end of the third switching tube is used for receiving the input voltage, the control unit is connected with the input voltage and the control end of the third switching tube to control the opening and closing of the third switching tube, and the first end of the third switching tube is connected with the second control circuit.
7. The charging circuit of claim 6, wherein the control unit comprises a fourth resistor and a first capacitor, the first terminal of the fourth resistor is configured to receive the input voltage, the second terminal of the fourth resistor is connected to the control terminal of the third switching tube, the first terminal of the first capacitor is connected to the control terminal of the third switching tube, and the second terminal of the first capacitor is connected to the control terminal of the load switching tube.
8. The charging circuit of claim 6, wherein the third control circuit further comprises a fifth resistor, a first terminal of the fifth resistor being coupled to the first terminal of the third switching tube, and a second terminal of the fifth resistor being coupled to the second control circuit.
9. The charging circuit of claim 6, wherein the third control circuit further comprises a second voltage regulator, a cathode of the second voltage regulator is connected to the first end of the third switching tube, and an anode of the second voltage regulator is connected to the control unit and the second control circuit.
10. A DCDC switching power supply, comprising a load switching tube, a load capacitor and a charging circuit according to any one of claims 1 to 9, wherein a first end of the load switching tube is connected to the load capacitor, a second end of the load switching tube is used for receiving an input voltage, and a control end of the load switching tube is connected to the charging circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311590131.5A CN117595662A (en) | 2023-11-24 | 2023-11-24 | Charging circuit and DCDC switching power supply |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311590131.5A CN117595662A (en) | 2023-11-24 | 2023-11-24 | Charging circuit and DCDC switching power supply |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117595662A true CN117595662A (en) | 2024-02-23 |
Family
ID=89917957
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311590131.5A Pending CN117595662A (en) | 2023-11-24 | 2023-11-24 | Charging circuit and DCDC switching power supply |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117595662A (en) |
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2023
- 2023-11-24 CN CN202311590131.5A patent/CN117595662A/en active Pending
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