CN210074760U - Switching power supply output overvoltage protection circuit - Google Patents
Switching power supply output overvoltage protection circuit Download PDFInfo
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- CN210074760U CN210074760U CN201921150933.3U CN201921150933U CN210074760U CN 210074760 U CN210074760 U CN 210074760U CN 201921150933 U CN201921150933 U CN 201921150933U CN 210074760 U CN210074760 U CN 210074760U
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Abstract
The utility model provides a switch power supply output overvoltage protection circuit, which comprises a detection module for detecting output voltage, a processing module for storing information provided by the detection module and performing processing conversion, a control module for receiving the information transmitted by the processing module and controlling the power supply to work, and an energy storage module for providing required electric energy for the modules; the utility model discloses an increase an energy storage circuit and continuously provide the energy for each module in the output overvoltage crowbar for processing module's abnormal data can keep, and further, the control IC of the specific control module circuit of rethread can lock dead switching power supply realizes locking the function, guarantees the product and resumes normal condition after the input resets, increases the reliability.
Description
Technical Field
The utility model relates to a power field, it is concrete, relate to switching power supply's output overvoltage protection.
Background
The switch power supply is a high-frequency electric energy conversion device, is one of power supplies, has the advantages of high efficiency, small volume, high reliability and wide application range compared with another power supply, namely a linear power supply, so that the switch power supply is the electric energy conversion device occupying the largest proportion on the market, is widely applied to a plurality of fields of industrial automation, military equipment, scientific research equipment, LED illumination, industrial control equipment, communication equipment, power equipment, instruments, medical equipment, semiconductor refrigeration and heating and the like, and has a long-term future.
The output overvoltage protection is a more important performance of the switching power supply, is a judgment standard when a customer selects, and the existing common output overvoltage protection modes comprise clamp protection, hiccup protection and lock-up protection. The clamp protection generally realizes the overvoltage protection function by adding a voltage regulator tube at the periphery of the IC, the hiccup protection realizes the overvoltage protection function by outputting overvoltage to trigger other protection of the IC, the functional modes of the protection circuits do not turn off the output, the output has energy all the time, and the product is easy to damage customers, so that the safety of the protection form is lower, and under the influence of the environmental temperature, the voltage value of the output overvoltage protection also has larger deviation and low reliability. The lock-up protection is the safest mode in the output overvoltage protection mode, the output overvoltage shuts off the output, and the current situation of the output shutdown is kept unless the fault is eliminated. The existing output overvoltage protection mode mainly depends on the protection mode of the control IC, less ICs with overvoltage locking protection modes are used in the actual product design, and more ICs without overvoltage protection modes or non-locking protection modes are used in a large amount.
SUMMERY OF THE UTILITY MODEL
In order to solve the problem that exists among the prior art, the utility model provides a switching power supply output overvoltage crowbar can realize the maintenance of data to can guarantee that the product resumes normal state after the input is reset, further, can also realize the output overvoltage crowbar of locking dead protection form.
The utility model discloses a realize through following technical scheme:
the utility model provides a switching power supply output overvoltage crowbar which characterized in that: the device comprises a detection module, a processing module, a control module and an energy storage module;
the input anode and the input cathode of the energy storage module are respectively used for being connected with the output anode and the output cathode of the switching power supply control IC energy supply circuit, and the output anode of the energy storage module is simultaneously connected with the power supply input end of the detection module, the power supply input end of the processing module and the power supply input end of the control module; the input end of the detection module is used for being connected with an output monitoring point, the output end of the detection module is connected with the input end of the processing module, the output end of the processing module is connected with the input end of the control module, and the output end of the control module is used for being connected with the enabling end of the switching power supply control IC;
the detection module is used for detecting the output voltage of the switching power supply or the voltage of the positive output end of the auxiliary winding, the processing module is used for storing the information provided by the detection module and carrying out processing conversion, the control module is used for receiving the information transmitted by the processing module and controlling the switching power supply to work, and the energy storage module is used for supplying power to the detection module, the processing module and the control module.
The energy storage module is characterized in that: the circuit comprises a first rectifier diode, a first capacitor, a voltage stabilizing diode and a current limiting module; the anode of the first rectifier diode is the input anode of the energy storage module, the cathode of the first rectifier diode is connected with one end of the current limiting module, the other end of the current limiting module is simultaneously connected with one end of the first capacitor and the cathode of the voltage stabilizing diode, and is the output anode of the energy storage module, the other end of the first capacitor is the input cathode of the energy storage module, the anode of the voltage stabilizing diode is connected with the other end of the first capacitor, and is the output cathode of the energy storage module, and the output cathode of the energy storage module and the input cathode are the same end and are connected with a reference ground; the current limiting module is used for limiting the current for charging the first capacitor and limiting the voltage of the first capacitor together with the voltage stabilizing diode.
For the improvement of the above energy storage module embodiment, its characteristics are: the current limiting circuit further comprises a second capacitor, one end of the second capacitor is connected with the cathode of the first rectifying diode and one end of the current limiting module, and the other end of the second capacitor is connected with the reference ground.
A specific implementation manner of the detection module is characterized in that: the circuit comprises a first resistor, a second resistor, a third resistor, a second rectifier diode, a controllable precise voltage-stabilizing source and a third capacitor;
one end of a third resistor is a power supply input end of the detection module, the anode of a second rectifier diode is an input end of the detection module, the cathode of the second rectifier diode is connected with one end of a first resistor, the other end of the first resistor is simultaneously connected with one end of a second resistor and a controllable precise voltage-stabilizing source reference electrode, the cathode of the controllable precise voltage-stabilizing source is simultaneously connected with the other end of the third resistor and one end of a third capacitor, the anode of the controllable precise voltage-stabilizing source is connected with the other end of the third capacitor and the other end of the second resistor, the anode of the controllable precise voltage-stabilizing source is a cathode of the detection module and is connected with a reference ground.
The control module is characterized in that: the control end of the controllable switch is the input end of the control module, the output end of the controllable switch is used for being connected with the enabling end of the control IC, the power supply end of the controllable switch is the power supply input end of the control module, and the grounding end of the controllable switch is connected with the reference ground.
A specific implementation manner of the processing module is characterized in that: the circuit comprises a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a fourth capacitor, a first NPN triode, a first PNP triode and a second PNP triode; one end of a fourth resistor, one end of a fifth resistor, an emitting electrode of the first PNP triode and one end of an eighth resistor are connected together to serve as a power supply input end of the processing module, the other end of the fourth resistor is connected with a base electrode of the second PNP triode to serve as an input end of the processing module, the other end of the fifth resistor is connected with an emitting electrode of the second PNP triode, a collecting electrode of the second PNP triode is simultaneously connected with one end of a fourth capacitor, one end of the sixth resistor and one end of the seventh resistor are connected with the collector of the first PNP triode, the other end of the seventh resistor is connected with the base of the first NPN triode, the other end of the eighth resistor is connected with the base of the first PNP triode and the collector of the first NPN triode, the other end of the eighth resistor is an output end of the processing module, and the emitter of the first NPN triode, the other end of the sixth resistor and the other end.
The working principle of the present invention will be described in detail with reference to specific embodiments, which are not repeated herein.
The utility model has the advantages as follows:
1. an energy storage circuit is independently added to continuously provide energy for each module in the output overvoltage protection circuit, so that data of the processing module can be kept, the product is ensured to be restored to a normal state after input reset, and the reliability is improved;
2. for a specific implementation circuit of the processing module, when output overvoltage is detected, the control module is triggered for protection, and after the output overvoltage is eliminated, the control module can still be triggered for protection, so that the output overvoltage protection in a locking protection mode is realized, the output overvoltage protection in the locking mode can also be realized when an IC product without the locking protection mode is used, and the application range and the safety and reliability are expanded;
3. for a specific implementation circuit of the energy storage module, when two capacitors are adopted, the protection function is removed, the power supply can be recovered after being restarted, and the second capacitor can enable the output of the energy storage module to be more durable, the locking time to be longer, and the control to be more diversified;
4. the energy storage module can directly take electricity from the auxiliary winding, the functional loop of the IC cannot be influenced, the output detection divider resistance is large, the output characteristic cannot be influenced, and therefore the circuit is independent and does not influence other performances of the product;
5. for a specific implementation circuit of the detection module, the influence of the ambient temperature is small, the detection is accurate, the output is directly turned off, and the safety is higher.
Drawings
Fig. 1 is a schematic circuit block diagram of the present invention;
fig. 2 is a specific circuit diagram of the first embodiment of the present invention;
fig. 3 is a specific circuit diagram of a second embodiment of the present invention;
fig. 4 is a specific circuit diagram of a third embodiment of the present invention.
Detailed Description
Fig. 1 is a schematic circuit block diagram of the present invention, which includes a detection module, a processing module, a control module and an energy storage module; the input anode and the input cathode of the energy storage module are respectively used for being connected with the output anode and the output cathode of the switching power supply control IC energy supply circuit, and the output anode of the energy storage module is simultaneously connected with the power supply input end of the detection module, the power supply input end of the processing module and the power supply input end of the control module; the input end of the detection module is used for being connected with an output monitoring point, the output end of the detection module is connected with the input end of the processing module, the output end of the processing module is connected with the input end of the control module, and the output end of the control module is used for being connected with the enabling end of the switching power supply control IC.
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in detail with reference to the following specific embodiments and accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
First embodiment
Fig. 2 is a schematic circuit diagram of the output overvoltage protection circuit of the switching power supply according to this embodiment.
The energy storage module includes: the circuit comprises a first rectifying diode D1, a first capacitor C1, a voltage stabilizing diode ZD and a current limiting module; the connection relationship is as follows: the anode of D1 is the input anode of the energy storage module, the cathode of D1 is connected with one end of the current limiting module, the other end of the current limiting module is connected with one end of a capacitor C1 and the cathode of a zener diode ZD and is the output anode of the energy storage module, and the anode of ZD, the other end of C1, the input cathode of the energy storage module and the output cathode of the energy storage module are simultaneously connected with the reference ground.
The detection module includes: the circuit comprises a first resistor R1, a second resistor R2, a third resistor R3, a second rectifier diode D2, a controllable precision voltage regulator U1 and a third capacitor C3; the connection relationship is that the positive output electrode of the energy storage module is connected with one end of R3 and is a power supply input end of the detection module, the anode of D2 is an input end of the detection module, the cathode of D2 is connected with one end of R1, the other end of R1 is connected with one end of R2 and a reference electrode of U1, the cathode of U1 is connected with the other end of R3 and one end of C3, and the anode of U1, the other end of C3 and the other end of R2 are output ends of the detection module and are connected with a reference ground.
The processing module comprises: a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a fourth capacitor C4, a first NPN triode NPN1, a first PNP triode PNP1, and a second PNP triode PNP 2; one end of R4 is connected with one end of R5, an emitter of PNP1 and one end of R8, the other end of R4 is connected with the output anode of the energy storage module, the base of PNP2 is connected with the base of PNP2, the other end of R5 is connected with the emitter of PNP2, the collector of PNP2 is connected with one end of C4, one end of R6, one end of R7 and the collector of PNP1, the other end of R7 is connected with the base of NPN1, the other end of R8 is connected with the base of PNP1 and the collector of NPN1, the emitter of NPN1 is connected with the other end of R6 and the other end of C4 for reference.
It should be noted that:
the current limiting module is used for limiting the current for charging the first capacitor, and limits the voltage of the first capacitor together with the voltage stabilizing diode, so that the voltage value of the first capacitor can be stabilized even if the energy supply voltage of the control IC is changed. The current limiting module may be implemented by using a resistor or an inductor, which is common knowledge to those skilled in the art and will not be described in detail herein.
The control module may be implemented by using an optical coupler and a relay, which are common knowledge to those skilled in the art and will not be described in detail herein.
The energy storage module works on the principle that the electric energy on the control IC power supply circuit charges the C1 through the D1 and the current limiting module, the ZD limits the voltage on the C1 to supply stable electric energy for a subsequent circuit, and the D1 has the function that the energy on the C1 cannot flow back to the control IC power supply circuit when the product is restarted due to the overvoltage protection circuit, and the energy is drawn from the control IC power supply circuit through the attempted restart of the product.
The working principle of the detection module is that information of the output voltage of the switching power supply is provided to the R1 through the D2, the information is provided to the reference electrode of the U1 after the voltage division of the R1 and the R2, when a voltage signal after the voltage division is larger than the reference voltage of the U1 (when an overvoltage state occurs), the cathode and the anode of the U1 are conducted, and the output end of the processing module is pulled down to a low level from an initial high level by the U1.
The working principle of the processing module is that under normal conditions, the input end of the processing module is at a high level, and then the PNP2 is in a cut-off state, that is, the potential of the collector of the PNP2 is low, then the base of the NPN1 is also at a low level, and the NPN1 is in a cut-off state, then the output end of the processing module is at a high level, and the base of the PNP1 is at a high level, and then the PNP1 is in a cut-off state, so that the potential of the collector of the PNP1 is ensured to be low; if an abnormal signal is transmitted from the checking module at this time, that is, the input end of the processing module is changed from high level to low level, then the base of the PNP2 is low level, at this time, the PNP2 is in a conducting state, then the base of the NPN1 is also high level, and the NPN1 is in a conducting state, then the output end of the processing module is low level, the base of the PNP1 is low level, at this time, the PNP1 is in a conducting state, the electric energy is continuously supplied to the collector of the PNP1, the collector of the PNP1 is locked high, then the base of the NPN1 is also high level, and the NPN1 is always in a conducting state.
The working principle of the embodiment as a whole is as follows:
the detection module directly or indirectly detects the output voltage, when the output voltage is in an overvoltage state, the output voltage continuously rises, and after the output voltage exceeds a set threshold value, the detection module outputs a high-level signal and transmits the high-level signal to the processing module. The processing module stores the information after receiving the processing module and outputs a continuous low level signal to the control module, at the moment, the processing module does not receive and process the message transmitted by the detection module any more, and the control module pulls down or lifts up the enabling end or the driving end of the switching power supply control IC after receiving the low level signal transmitted by the processing module, so that the switching power supply stops working. At this moment, the input of the switching power supply is not completely powered off, the control IC tries to restart (the control IC energy supply circuit can supply energy to the energy storage module in the process of trying to restart), the detection module detects that the output voltage is lower than the set overvoltage protection voltage, and tries to supply a normal product signal to the processing module, at this moment, the processing module does not receive and process information transmitted by the detection module any more, the low potential output is maintained to the control module, and the control module continuously pulls down or raises up the enable end or the drive end of the switching power supply control IC. And when the input end is powered off, the modules are restarted, and the processing module is unlocked, so that the problem of overvoltage protection is solved, and when the input end is powered on again, the product is recovered to be normal, and the locking protection mode of output overvoltage protection is realized.
The embodiment provides an energy storage module for supplying energy to other modules, and the specific implementation principle is that when a product works normally, a product power supply circuit charges a capacitor through a diode and a current limiting module, meanwhile, the voltage stabilizing diode clamps the voltage on the capacitor to a proper value, the capacitor energy storage element provides energy for other modules, when the product is over-voltage protected, the control IC attempts to restart, thereby intermittently energizing the product power supply circuit, this energy can be through the diode for the energy storage module function, because the one-way conduction nature of diode, the electric energy on the energy storage module can not reverse consume in supply circuit, so the inside energy of energy storage module can make output voltage lock dead the back at product overvoltage protection, and energy storage circuit can provide the electric energy for other modules of output overvoltage crowbar equally.
Second embodiment
As shown in fig. 3, the present embodiment is different from the first embodiment in that a specific structure of the control IC function circuit is provided, and the control IC function circuit is composed of an auxiliary winding T1, a rectifier diode D3 and a capacitor C5, a positive output end of the auxiliary winding T1 is connected to an anode of the rectifier diode D3, a negative output end of the auxiliary winding T1 is an output cathode of the control IC power supply circuit, a reference ground is connected, an anode of the rectifier diode D3 is an output anode of the control IC power supply circuit, and two ends of the capacitor C5 are respectively connected to the output anode of the control IC power supply circuit and the output cathode of the control IC power supply circuit; and the detection module in fig. 3 is connected to the positive output terminal of the auxiliary winding T1, and the voltage at the positive output terminal of the auxiliary winding is detected. Because the auxiliary winding T1 is coupled with the input winding and the output winding of the switching power supply, the auxiliary winding T1 has output voltage information, and the voltage signal on the auxiliary winding T1 is collected to ensure that the output voltage can be detected and the safe insulation between the input end and the output end of the switching power supply can be ensured.
Third embodiment
As shown in fig. 4, the difference between this embodiment and the first embodiment is that the energy storage module further includes a second capacitor C2, one end of the second capacitor C2 is connected to the cathode of the rectifier diode ZD, and the other end of the second capacitor C2 is connected to the negative input terminal of the energy storage module. Because the C1 and the C2 can always supply power to the PNP1 and the NPN1, the protection is locked, after the power supply is shut down, the energy of the C1 and the C2 is released, the PNP1 and the NPN1 cannot be conducted with each other, the protection function is released, and the power supply can be recovered after being restarted. In addition, this electric capacity voltage is greater than the voltage on the first electric capacity all the time, and can not be restricted by zener diode, and the maximum value is the voltage in the control IC energy supply circuit, so can increase the energy total value of energy storage module, makes the output of energy storage module more lasting, and the lock-in time is longer, is applicable to more different control ICs (the hiccup time that control IC tried to restart is longer).
The above embodiments are only used to help understanding the inventive concept of the present invention, and it will be obvious to those skilled in the art that the present invention may be modified and modified by the above descriptions and examples without departing from the principle of the present invention. In addition, all the connection relations referred to in the patent do not mean that the components are directly connected, but mean that a better connection structure can be formed by adding or reducing connection auxiliary components according to specific implementation conditions. The utility model provides an each technical feature can the interactive combination under the prerequisite of conflict each other.
Claims (6)
1. The utility model provides a switching power supply output overvoltage crowbar which characterized in that: the device comprises a detection module, a processing module, a control module and an energy storage module;
the input anode and the input cathode of the energy storage module are respectively used for being connected with the output anode and the output cathode of the switching power supply control IC energy supply circuit, and the output anode of the energy storage module is simultaneously connected with the power supply input end of the detection module, the power supply input end of the processing module and the power supply input end of the control module; the input end of the detection module is used for being connected with an output monitoring point, the output end of the detection module is connected with the input end of the processing module, the output end of the processing module is connected with the input end of the control module, and the output end of the control module is used for being connected with the enabling end of the switching power supply control IC;
the detection module is used for detecting the output voltage of the switching power supply or the voltage of the positive output end of the auxiliary winding, the processing module is used for storing the information provided by the detection module and carrying out processing conversion, the control module is used for receiving the information transmitted by the processing module and controlling the switching power supply to work, and the energy storage module is used for supplying power to the detection module, the processing module and the control module.
2. The switching power supply output overvoltage protection circuit according to claim 1, wherein: the energy storage module comprises a first rectifier diode, a first capacitor, a voltage stabilizing diode and a current limiting module; the anode of the first rectifier diode is the input anode of the energy storage module, the cathode of the first rectifier diode is connected with one end of the current limiting module, the other end of the current limiting module is simultaneously connected with one end of the first capacitor and the cathode of the voltage stabilizing diode, and is the output anode of the energy storage module, the other end of the first capacitor is the input cathode of the energy storage module, the anode of the voltage stabilizing diode is connected with the other end of the first capacitor, and is the output cathode of the energy storage module, and the output cathode of the energy storage module and the input cathode are the same end and are connected with a reference ground; the current limiting module is used for limiting the current for charging the first capacitor and limiting the voltage of the first capacitor together with the voltage stabilizing diode.
3. The switching power supply output overvoltage protection circuit according to claim 2, wherein: the energy storage module further comprises a second capacitor, one end of the second capacitor is connected with the cathode of the first rectifying diode and one end of the current limiting module, and the other end of the second capacitor is connected with the reference ground.
4. The switching power supply output overvoltage protection circuit according to claim 1, wherein: the detection module comprises a first resistor, a second resistor, a third resistor, a second rectifier diode, a controllable precise voltage-stabilizing source and a third capacitor;
one end of a third resistor is a power supply input end of the detection module, the anode of a second rectifier diode is an input end of the detection module, the cathode of the second rectifier diode is connected with one end of a first resistor, the other end of the first resistor is simultaneously connected with one end of a second resistor and a controllable precise voltage-stabilizing source reference electrode, the cathode of the controllable precise voltage-stabilizing source is simultaneously connected with the other end of the third resistor and one end of a third capacitor, the anode of the controllable precise voltage-stabilizing source is connected with the other end of the third capacitor and the other end of the second resistor, the anode of the controllable precise voltage-stabilizing source is a cathode of the detection module and is connected with a reference ground.
5. The switching power supply output overvoltage protection circuit according to claim 1, wherein: the control module is a controllable switch, the control end of the controllable switch is the input end of the control module, the output end of the controllable switch is used for being connected with the enabling end of the control IC, the power supply end of the controllable switch is the power supply input end of the control module, and the grounding end of the controllable switch is connected with the reference ground.
6. The switching power supply output overvoltage protection circuit according to claim 1, wherein: the processing module comprises a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a fourth capacitor, a first NPN triode, a first PNP triode and a second PNP triode; one end of a fourth resistor, one end of a fifth resistor, an emitting electrode of the first PNP triode and one end of an eighth resistor are connected together to serve as a power supply input end of the processing module, the other end of the fourth resistor is connected with a base electrode of the second PNP triode to serve as an input end of the processing module, the other end of the fifth resistor is connected with an emitting electrode of the second PNP triode, a collecting electrode of the second PNP triode is simultaneously connected with one end of a fourth capacitor, one end of the sixth resistor and one end of the seventh resistor are connected with the collector of the first PNP triode, the other end of the seventh resistor is connected with the base of the first NPN triode, the other end of the eighth resistor is connected with the base of the first PNP triode and the collector of the first NPN triode, the other end of the eighth resistor is an output end of the processing module, and the emitter of the first NPN triode, the other end of the sixth resistor and the other end.
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| CN201921150933.3U CN210074760U (en) | 2019-07-22 | 2019-07-22 | Switching power supply output overvoltage protection circuit |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN116505533A (en) * | 2023-06-25 | 2023-07-28 | 国家电投集团沧州新能源发电有限公司 | New energy power supply system |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116505533A (en) * | 2023-06-25 | 2023-07-28 | 国家电投集团沧州新能源发电有限公司 | New energy power supply system |
| CN116505533B (en) * | 2023-06-25 | 2023-09-01 | 国家电投集团沧州新能源发电有限公司 | New energy power supply system |
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