CN109672148B - Overvoltage protection circuit - Google Patents
Overvoltage protection circuit Download PDFInfo
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- CN109672148B CN109672148B CN201910129917.4A CN201910129917A CN109672148B CN 109672148 B CN109672148 B CN 109672148B CN 201910129917 A CN201910129917 A CN 201910129917A CN 109672148 B CN109672148 B CN 109672148B
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- power supply
- switch module
- overvoltage
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/10—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers
- H02H7/12—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers
- H02H7/1203—Circuits independent of the type of conversion
Abstract
The invention relates to an overvoltage protection circuit, when a PFC chip works and a boosting end has overvoltage, an overvoltage switch module conducts a first end and a second end of the overvoltage switch module, the voltage of the boosting end is transmitted to a power supply control module through a first voltage division module and a second voltage division module, so that the power supply control module controls the power supply switch module to switch off the first end and the second end of the power supply switch module, and the power supply of the PFC chip is interrupted to stop working. When the PFC chip is in a standby state, the first end and the second end of the overvoltage switch module are turned off, so that the subsequent first voltage division module, the second voltage division module, the power supply control module and the power supply switch module stop working. Therefore, overvoltage protection is provided when the PFC chip works, and the overvoltage protection is stopped when the PFC chip is in a standby state, so that the power loss of the PFC booster circuit is avoided, and the effect of saving energy consumption is achieved.
Description
Technical Field
The invention relates to the technical field of switching power supplies, in particular to an overvoltage protection circuit.
Background
PFC (Power Factor Correction) technology refers to a technology for improving the Power Factor of a Power-consuming device, and is commonly used in a switching Power supply circuit to improve the Power Factor of the Power supply circuit. PFC boost circuits are among the applications of PFC technology. In PFC boost circuit design, the PFC voltage is generally raised to 380V through a PFC chip, corresponding electronic components and a common driving switching tube. Correspondingly, in the PFC booster circuit, a 380V boosting end corresponds to a large electrolytic capacitor mounted.
In practical application, the 380V voltage at the boost end cannot be kept stable all the time, and when overvoltage occurs at the boost end, namely the voltage at the boost end is far higher than 380V, the large electrolytic capacitor can be damaged due to the overvoltage, and other elements can be damaged when the voltage is serious. Therefore, in the PFC boost circuit, an overvoltage protection circuit is generally required to solve the problem of voltage overvoltage at the boost terminal. However, the conventional overvoltage protection circuit applied to the PFC boost circuit may consume the power of the PFC boost circuit, thereby increasing the overall energy consumption of the PFC boost circuit.
Disclosure of Invention
Therefore, it is necessary to provide an overvoltage protection circuit for the conventional overvoltage protection circuit applied to the PFC boost circuit, which may consume the power of the PFC boost circuit and increase the overall energy consumption of the PFC boost circuit.
An overvoltage protection circuit is applied to a PFC booster circuit and comprises an overvoltage switch module, a first voltage division module, a second voltage division module, a power supply control module and a power supply switch module;
the first end of the overvoltage switch module is connected with the boost end of the PFC boost circuit through the first voltage division module, the second end of the overvoltage switch module is grounded through the second voltage division module, and the controlled end of the overvoltage switch module is also used for being connected with the power supply end of a PFC chip in the PFC boost circuit;
the second end of the overvoltage switch module is connected with the controlled end of the power supply switch module through the power supply control module;
the first end of the power supply switch module is used for connecting a power supply of the PFC chip, and the second end of the power supply switch module is used for connecting a power supply end.
According to the overvoltage protection circuit, when the PFC chip works and the boosting end is in overvoltage, the overvoltage switch module conducts the first end and the second end of the overvoltage switch module, the voltage of the boosting end is transmitted to the power supply control module through the first voltage division module and the second voltage division module, the power supply control module controls the power supply switch module to switch off the first end and the second end of the power supply switch module, and power supply of the PFC chip is interrupted to stop working. When the PFC chip is in a standby state, the first end and the second end of the overvoltage switch module are turned off, so that the subsequent first voltage division module, the second voltage division module, the power supply control module and the power supply switch module stop working. Therefore, overvoltage protection is provided when the PFC chip works, and the overvoltage protection is stopped when the PFC chip is in a standby state, so that the power loss of the PFC booster circuit is avoided, and the effect of saving energy consumption is achieved.
In one embodiment, the device further comprises a potential locking module;
one end of the potential locking module is connected with the second end of the overvoltage switch module, and the other end of the potential locking module is used for being connected with a power supply of the PFC chip.
In one embodiment, the overvoltage switching module comprises a field effect transistor;
the grid of the field effect transistor is the controlled end of the overvoltage switch module;
the source electrode of the field effect transistor is the second end of the overvoltage switch module;
the drain electrode of the field effect transistor is the first end of the overvoltage switch module.
In one embodiment, the power supply control module comprises a controllable precision voltage-stabilizing source;
the controlled end of the controllable precise voltage-stabilizing source is connected with the second end of the overvoltage switch module;
the negative pole of the controllable precise voltage-stabilizing source is used for connecting the controlled end of the power supply switch module, and the positive pole of the controllable precise voltage-stabilizing source is used for grounding.
In one embodiment, the potential locking module comprises a first triode;
the base electrode of the first triode is connected with the negative electrode of the controllable precise voltage-stabilizing source, the collector electrode of the first triode is connected with the controlled end of the controllable precise voltage-stabilizing source, and the emitting electrode of the first triode is used for being connected with the power supply of the PFC chip.
In one embodiment, the power supply switch module comprises a second triode;
the base electrode of the second triode is the controlled end of the power supply switch module;
the collector of the second triode is the first end of the power supply switch module;
and the emitter of the second triode is the second end of the power supply switch module.
In one embodiment, the device further comprises a third voltage division module and a fourth voltage division module;
the controlled end of the overvoltage switch module is used for being connected with the power supply end of the PFC chip through the third voltage division module and is also used for being grounded through the fourth voltage division module.
In one embodiment, the device further comprises a current limiting module;
and the controlled end of the controllable precise voltage-stabilizing source is used for being connected with a power supply through the current-limiting module, the collector of the first triode and the emitter of the first triode.
In one embodiment, the system further comprises a first isolation module;
and the second end of the power supply switch module is used for being connected with the power supply end through the isolation module.
In one embodiment, the system further comprises a second isolation module;
the power supply control module is connected with the controlled end of the power supply switch module through the second isolation module.
Drawings
FIG. 1 is a block diagram of an embodiment of an overvoltage protection circuit module;
FIG. 2 is a circuit diagram of an embodiment of an over-voltage protection circuit;
FIG. 3 is a circuit diagram of another embodiment of an overvoltage protection circuit;
FIG. 4 is a block diagram of an overvoltage protection circuit module according to another embodiment;
fig. 5 is a circuit diagram of an overvoltage protection circuit according to yet another embodiment.
Detailed Description
For better understanding of the objects, technical solutions and effects of the present invention, the present invention will be further explained with reference to the accompanying drawings and examples. It is to be noted that the following examples are given for the purpose of illustration only and are not intended to limit the invention
The embodiment of the invention provides an overvoltage protection circuit which comprises the following components:
fig. 1 is a block diagram of an overvoltage protection circuit according to an embodiment, and as shown in fig. 1, the overvoltage protection circuit is applied to a PFC boost circuit, and includes an overvoltage switch module 100, a first voltage division module 101, a second voltage division module 102, a power supply control module 103, and a power supply switch module 104;
a first end of the overvoltage switch module 100 is connected with a boost end of the PFC boost circuit through a first voltage division module 101, a second end of the overvoltage switch module 100 is used for grounding through a second voltage division module 102, and a controlled end of the overvoltage switch module 100 is also used for connecting a power supply end PFC-VCC of a PFC chip in the PFC boost circuit;
the controlled end of the overvoltage switch module 100 is connected to a power supply end PFC-VCC of a PFC chip in the PFC boost circuit, that is, the potential of the controlled end of the overvoltage switch module 100 is the same as the potential of the power supply end PFC-VCC of the PFC chip. When the PFC chip is operating, the power supply terminal PFC-VCC of the PFC chip has a chip power supply voltage potential of generally 12V or 5V, and after the controlled terminal of the overvoltage switch module 100 receives the potential, the first terminal and the second terminal thereof are turned on. When the PFC chip is in a standby state, the PFC-VCC terminal of the PFC chip has no supply voltage, no potential or a low potential, and the first terminal and the second terminal of the controlled terminal of the overvoltage switch module 100 are turned off.
The overvoltage switching module 100 may include a three-terminal switching device, such as an electronic switch, a triode, or a field effect transistor.
In one embodiment, fig. 2 is a circuit diagram of an embodiment of an overvoltage protection circuit, and as shown in fig. 2, the overvoltage switching module 100 includes a fet Q1;
the grid of the field effect transistor Q1 is the controlled end of the overvoltage switch module 100;
the source of the field effect transistor Q1 is the second terminal of the overvoltage switch module 100;
the drain of the fet Q1 is the first terminal of the overvoltage switch module 100.
For example, the overvoltage switching module 100 includes a fet Q1 including a fet, and the fet Q1 is an N-channel fet.
When the PFC chip operates, the gate of the fet Q1 is at a high potential, and the source and drain of the fet Q1 are turned on. Similarly, when the PFC chip is in standby, the gate of the fet Q1 is at a low potential, so that the source and the drain of the fet Q1 are turned off.
In one embodiment, the overvoltage protection circuit further comprises a third voltage division module and a fourth voltage division module;
the controlled terminal of the overvoltage switch module 100 is used for connecting the power supply terminal PFC-VCC of the PFC chip through the third voltage dividing module, and is also used for grounding through the fourth voltage dividing module.
The linear ratio of the potential of the controlled terminal of the overvoltage switch module 100 to the potential of the PFC-VCC terminal of the power supply terminal is set by the voltage division ratio of the third voltage division module and the fourth voltage division module, so as to set the conduction condition between the first terminal and the second terminal of the overvoltage switch module 100.
As shown in fig. 2, the third voltage division module includes a resistor R5, and the fourth voltage division module includes a resistor R6.
After the first terminal and the second terminal of the overvoltage switch module 100 are conducted, the potential of the boost terminal is divided by the first voltage dividing module 101 and the second voltage dividing module 102, that is, the potential of the second terminal of the overvoltage switch module 100 is distributed to the power supply control module 103. When the potential of the voltage boosting end is over-voltage, the potential of the second end of the over-voltage switch module 100 enables the power supply control module 103 to control the first end and the second end of the power supply switch module 104 to be switched off.
In one embodiment, as shown in fig. 2, the first voltage divider block 101 includes a resistor R1 and a resistor R2 connected in series, and the second voltage divider block 102 includes resistors R3 and R4 connected in parallel.
The second end of the overvoltage switch module 100 is connected with the controlled end of the power supply switch module 104 through the power supply control module 103;
the power supply control module 103 comprises a three-terminal switching device and a voltage regulator tube, wherein the three-terminal switching device comprises an electronic switch, a triode or a field effect tube and the like, and the voltage regulator tube comprises a common voltage regulator tube or a controllable precise voltage regulator source.
In one embodiment, fig. 3 is a circuit diagram of an overvoltage protection circuit according to another embodiment, as shown in fig. 3, the power supply control module 103 includes a controllable precision regulator U1;
the controlled end of the controllable precise voltage-stabilizing source U1 is connected with the second end of the overvoltage switch module;
the negative electrode of the controllable precise voltage-stabilizing source U1 is used for being connected with the controlled end of the power supply switch module, and the positive electrode of the controllable precise voltage-stabilizing source U1 is used for being grounded.
When the potential of the voltage boosting end is over-voltage, the potential of the second end of the over-voltage switch module 100 is input to the controlled end of the controllable precise voltage regulator U1, so that the negative electrode and the positive electrode of the controllable precise voltage regulator U1 are conducted, the ground potential is transmitted to the controlled end of the power supply switch module 104, and the first end and the second end of the power supply switch module are switched off. When the potential of the boosting end is normal, the negative electrode and the positive electrode of the controllable precise voltage-stabilizing source U1 are switched off.
In one embodiment, fig. 4 is a block diagram of an overvoltage protection circuit according to another embodiment, and as shown in fig. 4, the overvoltage protection circuit further includes a potential locking module 200;
one end of the potential lock module 200 is connected to the second end of the overvoltage switch module 100, and the other end of the potential lock module 200 is used for connecting a power supply of the PFC chip.
When the voltage of the boost end is over-voltage, the voltage of the voltage supply of the PFC chip provides voltage lock for the voltage of the second end of the overvoltage switch module 100 through the voltage lock module 200, which is respectively connected to the voltage of the second end of the overvoltage switch module 100 and the voltage of the power supply of the PFC chip, so as to keep the power supply control module 103 working normally.
In one embodiment, as shown in fig. 3, the potential locking module 200 includes a first transistor Q2;
the base electrode of the first triode Q2 is connected with the negative electrode of the controllable precision voltage-stabilizing source U1, the collector electrode of the first triode Q2 is connected with the controlled end of the controllable precision voltage-stabilizing source U1, and the emitting electrode of the first triode Q2 is used for being connected with a power supply source of the PFC chip.
The first triode Q2 is a PNP triode, after the negative electrode of the controllable precise voltage-stabilizing source U1 is conducted at the positive electrode, the base electrode of the first triode Q2 is pulled to the ground potential, the collector electrode and the emitter electrode of the first triode Q2 are conducted, the power supply of the PFC chip supplies power to the controlled end of the controllable precise voltage-stabilizing source U1, and the negative electrode and the positive electrode of the controllable precise voltage-stabilizing source U1 are ensured to be conducted stably.
In one embodiment, the device further comprises a current limiting module;
the controlled end of the controllable precise voltage-stabilizing source U1 is used for being connected with a power supply through the current-limiting module, the collector electrode of the first triode Q2 and the emitter electrode of the first triode Q2.
As shown in fig. 3, the current limiting module includes current limiting resistors R7 and R8.
The first end of the power supply switch module 104 is used for connecting a power supply of the PFC chip, and the second end of the power supply switch module 104 is used for connecting a power supply terminal PFC-VCC.
When the controlled terminal of the power supply switch module 104 is at a high potential, the first terminal and the second terminal of the power supply switch module 104 are conducted. When the power supply control module 103 outputs a low potential to the controlled terminal of the power supply switch module 104, the first terminal and the second terminal of the power supply switch module 104 are turned off.
In one embodiment, fig. 5 is a circuit diagram of an over-voltage protection circuit according to yet another embodiment, and as shown in fig. 5, the power supply switch module 104 includes a second transistor Q3;
the base of the second transistor Q3 is the controlled terminal of the power supply switch module 104;
the collector of the second transistor Q3 is the first terminal of the power supply switch module 104;
the emitter of the second transistor Q3 is the second terminal of the power switch module 104.
The second triode is an NPN type triode, and when the base of the second triode Q3 is at a high potential, the collector of the second triode Q3 is turned on with the emitter, and vice versa.
As shown in fig. 5, the controlled terminal of the power supply switch module 104 is connected to the first terminal of the power supply switch module 104 through an isolation resistor Rg to isolate the high potential signal from the low potential signal.
In one embodiment, the system further comprises a first isolation module;
and the second end of the power supply switch module is used for being connected with a power supply end PFC-VCC through the isolation module.
As shown in fig. 5, the first isolation module includes a first diode D1, a positive pole of the first diode D1 is connected to the second terminal of the power supply switch module, and a negative pole of the first diode is connected to the power supply terminal PFC-VCC.
In one embodiment, the system further comprises a second isolation module;
the power supply control module is connected with the controlled end of the power supply switch module through the second isolation module.
As shown in fig. 5, the second isolation module includes a second diode D2, a cathode of the second diode D2 is connected to the power supply control module, and an anode of the second diode D2 is connected to the controlled terminal of the power supply switch module.
In the overvoltage protection circuit according to the above embodiment, when the PFC chip operates and the boost terminal has an overvoltage, the overvoltage switch module 100 turns on the first terminal and the second terminal, and the voltage of the boost terminal is transmitted to the power supply control module 103 through the first voltage dividing module 101 and the second voltage dividing module 102, so that the power supply control module 103 controls the power supply switch module 104 to turn off the first terminal and the second terminal, and the power supply of the PFC chip is interrupted to stop operating. When the PFC chip is in a standby state, the overvoltage switch module 100 turns off the first terminal and the second terminal thereof, so that the subsequent first voltage division module 101, the second voltage division module 102, the power supply control module 103, and the power supply switch module 104 stop working. Therefore, overvoltage protection is provided when the PFC chip works, and the overvoltage protection is stopped when the PFC chip is in a standby state, so that the power loss of the PFC booster circuit is avoided, and the effect of saving energy consumption is achieved.
The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above examples only show some embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (10)
1. An overvoltage protection circuit is applied to a PFC booster circuit and is characterized by comprising an overvoltage switch module, a first voltage division module, a second voltage division module, a power supply control module and a power supply switch module;
the first end of the overvoltage switch module is connected with the boost end of the PFC boost circuit through the first voltage division module, the second end of the overvoltage switch module is grounded through the second voltage division module, and the controlled end of the overvoltage switch module is also connected with the power supply end of a PFC chip in the PFC boost circuit;
the second end of the overvoltage switch module is connected with the controlled end of the power supply switch module through the power supply control module;
the first end of the power supply switch module is used for being connected with a power supply of the PFC chip, and the second end of the power supply switch module is used for being connected with the power supply end.
2. The overvoltage protection circuit of claim 1, further comprising a potential lock module;
one end of the potential locking module is connected with the second end of the overvoltage switch module, and the other end of the potential locking module is used for being connected with a power supply of the PFC chip.
3. The overvoltage protection circuit of claim 1, wherein the overvoltage switching module comprises a field effect transistor;
the grid electrode of the field effect transistor is the controlled end of the overvoltage switch module;
the source electrode of the field effect transistor is the second end of the overvoltage switch module;
and the drain electrode of the field effect transistor is the first end of the overvoltage switch module.
4. The overvoltage protection circuit of claim 2, wherein the power supply control module comprises a controllable precision regulated voltage source;
the controlled end of the controllable precise voltage-stabilizing source is connected with the second end of the overvoltage switch module;
the negative electrode of the controllable precise voltage-stabilizing source is used for being connected with the controlled end of the power supply switch module, and the positive electrode of the controllable precise voltage-stabilizing source is used for being grounded.
5. The overvoltage protection circuit of claim 4, wherein the potential locking module comprises a first transistor;
the base electrode of the first triode is connected with the negative electrode of the controllable precise voltage-stabilizing source, the collector electrode of the first triode is connected with the controlled end of the controllable precise voltage-stabilizing source, and the emitting electrode of the first triode is used for being connected with the power supply of the PFC chip.
6. The overvoltage protection circuit of claim 1, wherein the power supply switch module comprises a second transistor;
the base electrode of the second triode is the controlled end of the power supply switch module;
the collector of the second triode is the first end of the power supply switch module;
and the emitter of the second triode is the second end of the power supply switch module.
7. The overvoltage protection circuit of claim 1, further comprising a third voltage divider module and a fourth voltage divider module;
and the controlled end of the overvoltage switch module is used for being connected with the power supply end of the PFC chip through the third voltage division module and is also used for being grounded through the fourth voltage division module.
8. The overvoltage protection circuit of claim 5, further comprising a current limiting module;
and the controlled end of the controllable precise voltage-stabilizing source is used for being connected with the power supply through the current-limiting module, the collector electrode of the first triode and the emitter electrode of the first triode.
9. The overvoltage protection circuit of claim 1, further comprising a first isolation module;
and the second end of the power supply switch module is used for being connected with the power supply end through the isolation module.
10. The overvoltage protection circuit of claim 1, further comprising a second isolation module;
the power supply control module is connected with the controlled end of the power supply switch module through the second isolation module.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201910129917.4A CN109672148B (en) | 2019-02-21 | 2019-02-21 | Overvoltage protection circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910129917.4A CN109672148B (en) | 2019-02-21 | 2019-02-21 | Overvoltage protection circuit |
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| CN109672148A CN109672148A (en) | 2019-04-23 |
| CN109672148B true CN109672148B (en) | 2020-09-29 |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102055233A (en) * | 2009-10-27 | 2011-05-11 | 沈阳晨讯希姆通科技有限公司 | Power supply unit |
| CN105610122A (en) * | 2016-02-19 | 2016-05-25 | 中国兵器工业集团第二一四研究所苏州研发中心 | Overvoltage, undervoltage and power-off protection circuit formed by MOS transistor |
| CN206211501U (en) * | 2016-11-30 | 2017-05-31 | 广东金莱特电器股份有限公司 | A kind of locked protection circuit of new output overvoltage |
| CN206323123U (en) * | 2016-12-15 | 2017-07-11 | 广州视源电子科技股份有限公司 | PFC overvoltage crowbars with auto-lock function |
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