CN213027804U - Overvoltage protection device and switching power supply - Google Patents
Overvoltage protection device and switching power supply Download PDFInfo
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- CN213027804U CN213027804U CN202021595810.3U CN202021595810U CN213027804U CN 213027804 U CN213027804 U CN 213027804U CN 202021595810 U CN202021595810 U CN 202021595810U CN 213027804 U CN213027804 U CN 213027804U
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Abstract
The utility model discloses an overvoltage protector and switching power supply, the device includes: the overvoltage judging part is used for detecting the output voltage of the voltage converter, providing a first judging signal when the output voltage is overvoltage, and providing a second judging signal when the output voltage is not overvoltage; and the input control part is connected with the overvoltage judging part and used for adjusting the output voltage to be reduced to a stable preset voltage under the condition of receiving the first judging signal, and the output control part does not control the output voltage under the condition of receiving the second judging signal.
Description
Technical Field
The utility model relates to the field of electronic technology, concretely relates to overvoltage protection device and switching power supply.
Background
The non-isolated switching power supply is a commonly used switching power supply, and generally performs power supply conversion required by voltage reduction, voltage boosting and the like, and then performs voltage stabilization conversion on the converted voltage to obtain an output voltage. In order to prevent the non-isolated switching power supply from damaging electric equipment due to the fact that the output voltage is too high, an overvoltage protection device is required to be arranged.
The overvoltage protection device in the prior art has the following problems: when the output voltage is overvoltage, the output of the non-isolated switch power supply is directly turned off, namely no output voltage exists, and the purpose of overvoltage protection is further achieved. In this way, no output voltage exists after each overvoltage protection is implemented, and then the switching device in the overvoltage protection device is turned on again, so that repeated triggering protection may occur, and the damage to the rear-stage device is easily caused.
Disclosure of Invention
The utility model discloses to the proposition of above problem, and provide an overvoltage protector that can not repeated trigger protection, still provide a switching power supply who possesses this kind of overvoltage protector simultaneously.
The utility model discloses a technical means be: there is provided an overvoltage protection device comprising:
the overvoltage judging part is used for detecting the output voltage of the voltage converter, providing a first judging signal when the output voltage is overvoltage, and providing a second judging signal when the output voltage is not overvoltage; and
and the input control part is connected with the overvoltage judging part and used for adjusting the output voltage to be reduced to a stable preset voltage under the condition of receiving the first judging signal, and not controlling the output voltage under the condition of receiving the second judging signal.
The utility model discloses another technical means who adopts is: provided is a switching power supply including:
the power converter is used for carrying out voltage reduction conversion on the power supply voltage and obtaining the input voltage to supply to the voltage converter;
the voltage converter is used for performing voltage stabilization conversion on the input voltage and obtaining the output voltage which can be supplied to electric equipment; and
the overvoltage protection device.
Since the technical scheme is used, the utility model provides an overvoltage protector and switching power supply, overvoltage protector can judge whether there is the condition of excessive pressure in the output voltage that the portion detected voltage converter through the excessive pressure, and based on whether excessive pressure of output voltage provides different judgement signals when overvoltage takes place for output voltage, input control portion will output voltage reduces to stable voltage of predetermineeing, reaches overvoltage protection's purpose. The utility model discloses do not adopt the overvoltage protection mode of direct turn-off output voltage, the condition of triggering the protection repeatedly can not appear, can avoid the problem that consequently the back level device that leads to damages.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
Wherein:
FIG. 1 is a block diagram of an embodiment of an overvoltage protection device;
FIG. 2 is a block diagram of the overvoltage protection device in one embodiment;
FIG. 3 is a schematic diagram of an example of the circuit of the overvoltage protection device and the switching power supply;
fig. 4 is a comparative example diagram of an overvoltage protection device.
In the figure: 1. the overvoltage protection device comprises an overvoltage protection device 2, a power converter 3, a voltage converter 11, an overvoltage judging part 12, an input control part 21, a voltage adjusting part 111, a voltage dividing module 112 and a controllable voltage stabilizing source.
Detailed Description
In order to make the objects, technical solutions and technical effects of the present invention clearer, the present invention will be described in detail with reference to the accompanying drawings and specific embodiments. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and not limitation. In the case of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other.
The utility model provides an overvoltage protector 1, in one embodiment, as shown in FIG. 1, the device can include an overvoltage judgment part 11 and an input control part 12. The overvoltage judging section 11 is configured to detect an output voltage of the voltage converter 3, and to provide a first judgment signal when the output voltage is overvoltage-generated, and to provide a second judgment signal when the output voltage is not overvoltage-generated.
The overvoltage determination unit 11 according to the present embodiment can detect the output voltage of the voltage converter 3, and specifically, can detect the output voltage in real time, or can detect the output voltage periodically at a certain sampling frequency. In addition to detecting the output voltage, the overvoltage judging unit 11 may judge whether the output voltage is overvoltage or not, and output a corresponding judgment signal based on a judgment result of whether the output voltage is overvoltage or not. Specifically, for example, if the output voltage exceeds an overvoltage protection threshold, the output voltage is considered to be over-voltage, and if the output voltage does not exceed the overvoltage protection threshold, the output voltage is considered to be not over-voltage. Further, it is also possible to sample the output voltage and obtain a corresponding sampled voltage, and then compare the sampled voltage with a reference voltage set for reference. And if the sampling voltage exceeds the reference voltage, the output voltage is considered to be overvoltage, and if the sampling voltage does not exceed the reference voltage, the output voltage is considered to be not overvoltage. When the overvoltage judging part 11 detects that the output voltage is overvoltage, it indicates that a problem occurs in a circuit related to the voltage converter 3, and overvoltage protection needs to be performed in time to avoid damage to the electric equipment.
In this embodiment, the first determination signal and the second determination signal output by the overvoltage determination unit 11 are different determination signals, so that after receiving the first determination signal or the second determination signal, whether the output voltage is overvoltage or not can be known according to the received different determination signals. For example, the first determination signal may be a low logic level, and the second determination signal may be a high logic level.
In this embodiment, the input control unit 12 is connected to the overvoltage determination unit 11, and controls whether to perform overvoltage protection. Specifically, the input control unit 12 adjusts the output voltage to be reduced to a stable preset voltage when receiving the first determination signal, and at this time, the input control unit 12 controls the overvoltage protection. The input control section 12 may control the output voltage to decrease and reach a stable preset voltage, which is lower than the overvoltage protection threshold and may be slightly higher than the normal output voltage. As long as the problems and faults that lead to an overvoltage of the output voltage are not relieved, e.g. a permanent short-circuit failure between the input and output of the voltage converter 3, the output voltage will remain at the above-mentioned stable preset voltage. The input control unit 12 does not control the output voltage when receiving the second determination signal, and does not perform overvoltage protection at this time.
In this embodiment, the overvoltage protection device 1 may detect whether the output voltage of the voltage converter 3 has an overvoltage condition through the overvoltage judging unit 11, and provide different judging signals based on whether the output voltage is overvoltage, and when the output voltage has an overvoltage, the input control unit 12 reduces the output voltage to a stable preset voltage, so as to achieve the purpose of overvoltage protection. The utility model discloses do not adopt the overvoltage protection mode of direct turn-off output voltage, the condition of triggering the protection repeatedly can not appear, can avoid the problem that consequently the back level device that leads to damages.
In one embodiment, as shown in fig. 1 and 2, the input control section 12 may adjust the output voltage by controlling the input voltage of the voltage converter 3. The output voltage changes with the change of the input voltage, and for example, when the short circuit failure occurs between the input end and the output end of the voltage converter 3, and the output voltage is the same as the input voltage, controlling the input voltage of the voltage converter 3 is equivalent to adjusting the output voltage. The input voltage may be provided by a power converter 2, the input control unit 12 is connected to a voltage adjustment terminal of the power converter 2, and the input control unit 12 may control the input voltage by controlling a supply device of the input voltage, for example, an output of the power converter 2. Specifically, the voltage adjustment terminal of the power converter 2 may be a sampling feedback terminal of the input voltage provided by the power converter 2, and the input control unit 12 changes the control voltage of the voltage adjustment terminal to change the sampling feedback voltage corresponding to the input voltage, so that the power converter 2 adjusts the input voltage provided by the power converter based on the change of the sampling feedback voltage. The power converter 2 is a device for performing voltage conversion, and for example, the power converter 2 may be a BUCK converter (BUCK circuit), a BOOST converter (BOOST circuit), a BUCK-BOOST converter (BUCK-BOOST circuit), or other voltage conversion devices. The embodiment adjusts the output voltage by controlling the input voltage to be reduced, and is easier and safer to operate when an overvoltage fault occurs.
In one embodiment, referring to fig. 2, the input control unit 12 may include a controllable switch having at least two operating states, i.e., an on state and an off state, wherein the circuit in which the controllable switch is located is a closed circuit when the controllable switch is in the on state, and the circuit in which the controllable switch is located is an open circuit when the controllable switch is in the off state. The controllable switch is in an on state when receiving the first judgment signal, and is in an off state when receiving the second judgment signal. When the controllable switch is in an on state, the controllable switch increases the control voltage input by the voltage adjusting end. The power converter 2 changes the input voltage supplied to the voltage converter 3 based on the control voltage, and the input voltage is lowered when the control voltage is increased.
When the controllable switch is in an on state based on the first determination signal, the input voltage is decreased to the preset voltage at which the output voltage reaches a stable state, and when the output voltage is the same as the input voltage due to a short circuit between the input and the output of the voltage converter 3, the input voltage is decreased to the preset voltage, and at this time, the input voltage does not need to be decreased continuously, and the controllable switch may enter an off state. Further, the overvoltage judging part 11 may provide a third judging signal when the output voltage reaches the stable preset voltage, in addition to providing the first judging signal when the output voltage is overvoltage and providing the second judging signal when the output voltage is not overvoltage. The controllable switch enters an on state based on the first judgment signal and enters an off state based on both the second judgment signal and the third judgment signal. When the output voltage is over-voltage, the over-voltage judging part 11 generates the first judging signal, the controllable switch is in an on state, the input voltage is controlled to be reduced, the output voltage reaches the stable preset voltage, and at this time, the problem and the fault of the over-voltage of the output voltage are not eliminated, the over-voltage judging part 11 generates the third judging signal, the controllable switch is in an off state, the input voltage is not reduced any more, the output voltage keeps the stable preset voltage, and when the problem and the fault of the over-voltage of the output voltage are not over-voltage or the problem and the fault of the over-voltage of the output voltage are eliminated, the over-voltage judging part 11 generates the second judging signal, the controllable switch is in an off state, and the controllable switch does not control the control voltage input by the voltage adjusting terminal. The overvoltage protection device of the embodiment only adopts one controllable switch, so that the number of components is relatively small, and the hardware cost is low.
In this embodiment, the first determination signal, the second determination signal and the third determination signal may be automatically generated based on the overvoltage determination unit 11 sampling the current voltage of the output voltage, specifically, the first determination signal is generated when the output voltage exceeding the overvoltage protection value is sampled, the third determination signal is generated when the output voltage not exceeding the overvoltage protection value but exceeding the normal voltage is sampled, and the second determination signal is generated when the output voltage at the normal voltage is sampled.
In one embodiment, referring to fig. 2, the overvoltage judging part 11 may include a voltage dividing module 111 and a controllable regulator 112. The voltage dividing module 111 is configured to divide the output voltage and generate a first voltage. The controllable regulator 112 is controlled by the first voltage for switching states, and the controllable regulator 112 switches its state according to the received first voltage. When the first voltage is higher than the reference voltage, the controllable regulator 112 is in a conducting state and outputs the first determination signal. When the first voltage is lower than the reference voltage, the controllable regulator 112 is in a cut-off state and outputs the second determination signal. Further, when the first voltage is equal to the reference voltage, the controllable voltage regulator 112 is in an amplification state and outputs a third determination signal, and the output voltage is kept at the stable preset voltage until the problem or fault that the output voltage is overvoltage is eliminated. When the controllable regulator supply 112 is in a conducting state, the controllable switch is in an on state. The controllable switch is in an off state when the controllable regulator 112 is in an off state and an amplified state.
In one embodiment, referring to fig. 3, the voltage dividing module 111 may include a first voltage dividing resistor R60 and a second voltage dividing resistor R54 connected in series between the output terminal and the ground terminal of the voltage converter 3. The controllable voltage-stabilizing source V5 is provided with a reference electrode E, an anode C and a cathode B, and further, the controllable voltage-stabilizing source V5 can adopt a controllable precise voltage-stabilizing source with the model number of TL 431. For example, the reference voltage of the controllable regulator V5 may be 2.5V, and when the first voltage is higher than 2.5V, the controllable regulator V5 is in a conducting state and outputs the first determination signal, which is shown in fig. 3 as a low logic level. When the first voltage is lower than 2.5V, the controllable regulator V5 is in a cut-off state and outputs the second determination signal, which is shown in fig. 3 as a high logic level. In this embodiment, when the output voltage is not over-voltage, the controllable regulator V5 is in a cut-off state, and the controllable switch is in an off state, and the whole overvoltage protection device 1 consumes power only by the voltage dividing module 111 including the first voltage dividing resistor R60 and the second voltage dividing resistor R54, which can avoid the problem of large power consumption when the switching power supply is in a normal operating state.
Further, when the first voltage is equal to 2.5V, the controllable voltage regulator V5 is in an amplification state and outputs a third determination signal, the third determination signal shown in fig. 3 is a high logic level, and a voltage of the high logic level corresponding to the third determination signal is different from a voltage of the high logic level corresponding to the second determination signal. The reference electrode E and the anode C are connected to two ends of the second voltage-dividing resistor R54, respectively, and the cathode B is connected to the input control unit 12. The second voltage-dividing resistor R54 may also be connected in parallel with the capacitor C30. The output voltage shown in fig. 3 is, for example, 3.3V in a normal condition, and this output voltage is only an example, and other output voltage values required by the electric device may be adjusted according to actual needs, and the voltage converter 3 may also be replaced.
By way of example only, the voltage converter 3 shown in fig. 3 includes a first input capacitor C1661, a second input capacitor C135, a linear regulator chip V109 of type BU33TD3WG, a first output capacitor C136, and a second output capacitor C137. The first input capacitor C1661 and the second input capacitor C135 are mutually connected in parallel between the VIN pin of the linear regulator chip V109 and the ground GND, and the VIN pin of the linear regulator chip V109 is further connected with the STBY pin of the linear regulator chip V109. The first output capacitor C136 and the second output capacitor C137 are coupled in parallel between the OUT pin of the linear regulator chip V109 and the ground GND, and the GND pin of the linear regulator chip V109 is directly connected to the ground GND. The voltage between the OUT pin of the linear regulator chip V109 and the ground GND is the output voltage, and both ends of the voltage dividing module 111 included in the overvoltage determination unit 11 are respectively connected to the OUT pin of the linear regulator chip V109 and the ground GND. The voltage converter 3 may also adopt other voltage conversion chips and corresponding peripheral circuit structures.
In one embodiment, referring to fig. 3, the input control part 12 may further include a driving resistor R65 and a bias resistor R66. The controllable switch may be a switch transistor T3, the switch transistor T3 having a control terminal, a first switch terminal, and a second switch terminal. The switch tube T3 may be a PNP triode, a PMOS transistor, or another controllable electronic switch. When the switch tube T3 is a PNP triode, the control end is the base of the PNP triode, the first switch end is the collector of the PNP triode, and the second switch end is the emitter of the PNP triode. When the switch transistor T3 is a PMOS transistor, the control terminal is a gate of the PMOS transistor, the first switch terminal is a drain of the PMOS transistor, and the second switch terminal is a source of the PMOS transistor. The control end is connected with the cathode B of the controllable voltage-stabilizing source V5 through the driving resistor R65. The first switch end is connected with the voltage adjusting end. The second switch terminal is connected to the output terminal of the power converter 2. And two ends of the bias resistor R66 are respectively connected with the second switch end and the cathode B.
In one embodiment, when the output voltage is over-voltage, the input control portion 12 may adjust the output voltage to the preset voltage by: uo ═ 2.5 (R60+ R54) ]/R54, where Uo denotes the output voltage, R60 denotes the resistance value of the first voltage-dividing resistor R60, R54 denotes the resistance value of the second voltage-dividing resistor R54, and 2.5 denotes the voltage applied between the reference pole E and the anode C of the controlled regulator V5, which is equal to the reference voltage value of the controlled regulator V5. For example, fig. 3 shows that the output voltage Uo ═ 2.5 × (12K +22K) ]/22K ═ 3.863V to reach the preset voltage, the output voltage will always be stabilized at 3.863V, which is higher than the normal voltage but lower than the overvoltage protection value, as long as the overvoltage fault is not relieved, and the stabilized output voltage can ensure that the overvoltage protection is not repeatedly triggered.
Fig. 4 shows a comparison example of the overvoltage protection device 1, and compared with fig. 3 and 4, the input control section 12 in fig. 4 includes a resistor R1, a resistor R2, a resistor R3, a MOS transistor Q1, and a MOS transistor Q2. When the output voltage is overvoltage, the MOS transistor Q2 is turned off, then the MOS transistor Q1 is turned off, no output voltage exists at the moment, and the purpose of overvoltage protection is achieved. The resistor R1, the resistor R2, and the resistor R3 in fig. 4 generate large power consumption even in a normal condition where the output voltage is not over-voltage, and the input control unit 12 has many component devices and high hardware cost. If the overvoltage fault is not eliminated continuously, after the voltage protection is output each time, the output voltage is 0, the MOS tube Q1 and the MOS tube Q2 are turned on again, and the overvoltage protection is triggered again by the higher output voltage. As described above, fig. 3 configured with the driving resistor R65, the bias resistor R66, and the switching transistor T3 does not generate power consumption under the normal condition that the output voltage is not over-voltage, has fewer components and low hardware cost, and does not generate the condition of repeatedly triggering over-voltage protection. Therefore, the overvoltage protection performance of the embodiment is better and the effect is more obvious.
The utility model also provides a switching power supply, in an embodiment, refer to fig. 1 and fig. 2 and show, switching power supply can include power converter 2, voltage converter 3 and any above-mentioned embodiment overvoltage protection device 1. The power converter 2 may be configured to convert a supply voltage to obtain the input voltage supply voltage converter 3. The voltage converter 3 is configured to perform voltage-stabilizing conversion on the input voltage and obtain the output voltage that can be supplied to the electric device. The power converter 2 may perform buck conversion, boost conversion, buck-boost conversion, or other voltage conversion on the supply voltage to obtain the input voltage, for example, the supply voltage shown in fig. 3 is 9.5V, and the input voltage is 5V, which is equivalent to the power converter 2 in fig. 3 performing buck conversion.
In one embodiment, as shown with reference to fig. 2, the power converter 2 may include a voltage adjustment section 21. The voltage adjustment unit 21 is connected to the output terminal and the voltage adjustment terminal of the power converter 2 and the input control unit 12. The input control unit 12 controls the input voltage via the voltage adjustment unit 21.
In one embodiment, referring to fig. 3, the voltage adjustment part 21 includes: a first adjusting resistor R182 and a second adjusting resistor R183; the first adjusting resistor R182 and the second adjusting resistor R183 are connected in series between the output end and the ground end of the power converter 2, and the series connection point of the first adjusting resistor R182 and the second adjusting resistor R183 is connected to the input control unit 12 and is connected to the voltage adjusting end via a feedback resistor R13.
Illustratively, referring to fig. 3, the power converter 2 may further include a capacitor C163, a resistor R12, a resistor R11, a feedback resistor R13, a capacitor C6, an inductor L109, and a power management chip U111 of model MP1657, in addition to the voltage adjustment portion 21. The power supply voltage is input to the power management chip U111 through the capacitor C163, one end of the capacitor C163 is connected to the VIN pin of the power management chip U111, and the other end is connected to the GND pin of the power management chip U111 and the ground GND. The two ends of the resistor R12 respectively receive the power supply voltage and an EN pin connected with a power management chip U111. The SW pin of the power management chip U111 is connected to one end of an inductor L109, and the other end of the inductor L109 serves as the output end of the power converter 2. The SW pin of the power management chip U111 is also connected with the BST pin of the power management chip U111 through a capacitor C6 and a resistor R11 which are connected in series. The FB pin of the power management chip U111 serves as a voltage adjustment terminal of the power converter 2, the FB pin of the power management chip U111 is connected to the input control unit 12 via a feedback resistor R13, and specifically, the FB pin of the power management chip U111 is connected to the first switch terminal of the switch tube T3 via a feedback resistor R13. The FB pin of the power management chip U111 is further connected to a series connection point of the first adjusting resistor and the second adjusting resistor via a feedback resistor R13.
Illustratively, the overvoltage protection process of the switching power supply is specifically described in conjunction with fig. 3. When the output voltage is not overvoltage, the first voltage V1 obtained between the reference electrode E and the anode C of the controllable voltage regulator V5 is 3.3 × 22/(12+22) is 2.135V <2.5V, the controllable voltage regulator V5 is cut off, the switch tube T3 is turned off, and overvoltage protection is not executed. When the output voltage exceeds an overvoltage protection value, the first voltage V1 obtained between the reference electrode E and the anode C of the controllable voltage regulator V5 is 5 × 22/(12+22) ═ 3.235V >2.5V, the controllable voltage regulator V5 is conducted, the cathode B of the controllable voltage regulator V5 outputs a low logic level, the switch tube T3 is turned on, the first adjusting resistor R182 is bypassed, the voltage of the two ends of the second adjusting resistor R183 is increased, the voltage of the FB pin of the power management chip U111 is increased, loop control is performed inside the power management chip U111 and the output PWM duty ratio is adjusted, so that the input voltage of 5V is reduced, the output voltage is reduced along with the voltage, the first voltage V1 obtained between the reference electrode E and the anode C of the controllable voltage regulator V5 is 3.863/(12 +22) — 2.5V, the voltage regulator V5 enters an amplification state, the switch tube T3 is turned off, and the cathode B of the controllable voltage regulator V66 is communicated through the bias converter 39R 5, a steady-state loop is formed, and the output voltage is always stabilized at 3.863V as long as the problem and fault causing the output voltage to be over-voltage are not relieved.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can substitute or change the technical solution and the inventive concept of the present invention within the technical scope of the present invention. Furthermore, although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.
Claims (10)
1. An overvoltage protection device, characterized in that the device comprises:
the overvoltage judging part is used for detecting the output voltage of the voltage converter, providing a first judging signal when the output voltage is overvoltage, and providing a second judging signal when the output voltage is not overvoltage; and
and the input control part is connected with the overvoltage judging part and used for adjusting the output voltage to be reduced to a stable preset voltage under the condition of receiving the first judging signal, and not controlling the output voltage under the condition of receiving the second judging signal.
2. The overvoltage protection device of claim 1, wherein the input control portion regulates the output voltage by controlling an input voltage of the voltage converter; the input voltage is provided by a power converter, and the input control part is connected with a voltage adjusting end of the power converter.
3. The overvoltage protection device of claim 2,
the input control section includes: a controllable switch; the controllable switch is in an on state when receiving the first judgment signal, and is in an off state when receiving the second judgment signal;
when the controllable switch is in an on state, the controllable switch increases the control voltage input by the voltage adjusting end; the power converter changes the input voltage supplied to the voltage converter based on the control voltage, the input voltage decreasing if the control voltage increases;
when the controllable switch is in an off state, the controllable switch does not control the control voltage input by the voltage adjusting end.
4. The overvoltage protection device according to claim 3, wherein the overvoltage judging section includes:
the voltage division module is used for dividing the output voltage and generating a first voltage; and
the controllable voltage stabilization source is controlled by the first voltage to carry out state switching; when the first voltage is higher than the reference voltage, the controllable voltage-stabilizing source is in a conducting state and outputs the first judgment signal; when the first voltage is lower than the reference voltage, the controllable voltage-stabilizing source is in a cut-off state and outputs the second judgment signal;
when the controllable voltage-stabilizing source is in a conducting state, the controllable switch is in an on state;
and when the controllable voltage-stabilizing source is in a cut-off state, the controllable switch is in a closed state.
5. The overvoltage protection device of claim 4,
the voltage division module comprises a first voltage division resistor and a second voltage division resistor which are connected between the output end of the voltage converter and the ground end in series;
the controllable voltage-stabilizing source is provided with a reference electrode, an anode and a cathode; two ends of the second voltage-dividing resistor are respectively connected with the reference electrode and the anode; the cathode is connected with the input control part.
6. The overvoltage protection device of claim 5,
the input control section further includes: a drive resistor and a bias resistor; the controllable switch is a switch tube, and the switch tube is provided with a control end, a first switch end and a second switch end; the control end is connected with the cathode through the driving resistor; the first switch end is connected with the voltage adjusting end; the second switch end is connected with the output end of the power converter; two ends of the bias resistor are respectively connected with the second switch end and the cathode;
and under the condition that the output voltage is reduced to a stable preset voltage, the controllable voltage-stabilizing source is in an amplifying state.
7. The overvoltage protection device of claim 6,
when the output voltage is over-voltage, the input control part adjusts the output voltage to reach the preset voltage as follows:
uo ═ 2.5 (R60+ R54) ]/R54, where Uo represents the output voltage, R60 represents the resistance value of the first voltage-dividing resistor, and R54 represents the resistance value of the second voltage-dividing resistor.
8. A switching power supply, characterized in that the switching power supply comprises:
the power converter is used for converting the power supply voltage to obtain an input voltage supply voltage converter;
the voltage converter is used for performing voltage stabilization conversion on the input voltage and obtaining an output voltage which can be supplied to electric equipment; and
the overvoltage protection device of any one of claims 1 to 7.
9. The switching power supply according to claim 8, wherein the power converter comprises:
the voltage adjusting part is connected with the output end and the voltage adjusting end of the power converter and the input control part; the input control unit controls the input voltage via the voltage adjustment unit.
10. The switching power supply according to claim 9, wherein the voltage adjustment section includes: a first adjusting resistor and a second adjusting resistor; the first adjusting resistor and the second adjusting resistor are connected between the output end of the power converter and the ground end in series, and the series connection point of the first adjusting resistor and the second adjusting resistor is connected with the input control part and is connected with the voltage adjusting end through a feedback resistor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202021595810.3U CN213027804U (en) | 2020-08-03 | 2020-08-03 | Overvoltage protection device and switching power supply |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202021595810.3U CN213027804U (en) | 2020-08-03 | 2020-08-03 | Overvoltage protection device and switching power supply |
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| CN213027804U true CN213027804U (en) | 2021-04-20 |
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