CN210468787U - Direct current power supply output overvoltage protection circuit - Google Patents
Direct current power supply output overvoltage protection circuit Download PDFInfo
- Publication number
- CN210468787U CN210468787U CN201920440480.1U CN201920440480U CN210468787U CN 210468787 U CN210468787 U CN 210468787U CN 201920440480 U CN201920440480 U CN 201920440480U CN 210468787 U CN210468787 U CN 210468787U
- Authority
- CN
- China
- Prior art keywords
- resistor
- power supply
- circuit
- overvoltage protection
- terminal
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Landscapes
- Dc-Dc Converters (AREA)
Abstract
The utility model discloses a DC power supply output overvoltage crowbar, include: the reference circuit is used for acquiring overvoltage protection point information; the sampling circuit is connected to the output positive end and the output negative end of the direct-current power supply and used for acquiring and processing output voltage information of the direct-current power supply to obtain sampling information; the comparison circuit is connected with the reference circuit and the sampling circuit and is used for receiving and processing the overvoltage protection point information and the sampling information to obtain a comparison signal; the isolation conversion circuit is connected with the comparison circuit and used for receiving and processing the comparison signal to obtain a conversion signal; and the driving circuit is connected with the isolation conversion circuit and used for receiving the conversion signal and outputting a driving signal corresponding to the conversion signal. The utility model provides a DC power supply output overvoltage crowbar has the advantage that can accurately set up the overvoltage crowbar to and good electrical safety performance and self-resuming function.
Description
Technical Field
The utility model belongs to the technical field of the electron, concretely relates to DC power supply output overvoltage crowbar.
Background
In power supply systems, the most prone faults are short circuits, overloads, grounding, lightning strikes, etc. In order to ensure the safe and reliable operation of the power supply system, a protection device must be installed in order to monitor the working condition of the power supply system, find out a fault in time and cut off the power supply of the faulty equipment, so as to prevent the accident from expanding, and overvoltage protection is one of the protection devices.
At present, the following methods can be used for realizing the overvoltage protection of the output of the direct-current power supply: firstly, an overvoltage and constant current conversion restorable circuit designed by using a silicon controlled rectifier is utilized; a restorable overvoltage protection circuit designed by a voltage-regulator tube and an optocoupler; and thirdly, a locking overvoltage protection circuit designed by utilizing a triode and an optocoupler.
However, the first method is simple to implement, but needs to share part of elements with the constant current circuit, and the independence of the protection function is poor; in the second method, the circuit can be designed with overvoltage points, the functions are relatively independent, but the voltage stabilizing value and the temperature drift of the voltage stabilizing tube can influence the height of the overvoltage points; the third method can improve the accuracy of the overvoltage point, but when the overvoltage fault is relieved, the power supply needs to be restarted to enable the power supply to recover the normal state.
Disclosure of Invention
In order to solve the above-mentioned problem that exists among the prior art, the utility model provides a DC power supply output overvoltage crowbar. The to-be-solved technical problem of the utility model is realized through following technical scheme:
a dc power supply output overvoltage protection circuit comprising:
the reference circuit is used for acquiring overvoltage protection point information;
the sampling circuit is connected to the output positive end and the output negative end of the direct-current power supply and used for acquiring and processing output voltage information of the direct-current power supply to obtain sampling information;
the comparison circuit is connected with the reference circuit and the sampling circuit and is used for receiving and processing the overvoltage protection point information and the sampling information to obtain a comparison signal;
the isolation conversion circuit is connected with the comparison circuit and used for receiving and processing the comparison signal to obtain a conversion signal;
and the driving circuit is connected with the isolation conversion circuit and used for receiving the conversion signal and outputting a driving signal corresponding to the conversion signal.
In an embodiment of the present invention, the reference circuit includes a voltage regulator U1 and a first resistor R1, wherein the cathode of the voltage regulator U1 is connected to the resistor R1, the anode of the integrated circuit U1 is connected to the SGND terminal, and the reference electrode of the voltage regulator U1 is shorted with the cathode.
In an embodiment of the present invention, the sampling circuit includes a second resistor R2 and a third resistor R3, wherein the second resistor R2 is connected to the positive output terminal of the dc power supply, and the third resistor R3 is connected to the second resistor R2 and the negative output terminal of the dc power supply.
In an embodiment of the present invention, the comparison circuit includes an operational amplifier U2, wherein, the inverting input terminal of the operational amplifier U2 is connected to the reference electrode of the voltage regulator U1, the non-inverting input terminal of the operational amplifier U2 is connected to the second resistor R2 and the common terminal of the third resistor R3, the negative voltage power supply terminal of the operational amplifier U2 is connected to the SGND terminal, and the power supply terminal of the operational amplifier U2 is connected to the VCC 2.
In an embodiment of the present invention, the isolation conversion circuit includes a fourth resistor R4, a photocoupler U3, a triode Q1, a fifth resistor R5, a sixth resistor R6 and a seventh resistor R7, wherein the fourth resistor R4 is connected in parallel with both ends of a light emitting diode of the photocoupler U3, a collector of the photocoupler U3 is connected to a collector of the triode Q1 and a power VCC1, an emitter of the photocoupler U3 is connected to a base of the triode Q1, the fifth resistor R5 is connected to an emitter of the triode Q1 and the sixth resistor R6, the other end of the sixth resistor R6 is connected to a GND terminal, and the seventh resistor R7 is connected between a positive electrode of the light emitting diode of the photocoupler U3 and an output terminal of the operational amplifier U2.
In an embodiment of the present invention, the isolation conversion circuit further includes a diode D1, the anode of the diode D1 is connected to the seventh resistor R7, and the cathode of the diode D1 is connected to the anode of the light emitting diode of the photocoupler U3.
In an embodiment of the present invention, the power supply further includes a switch Q2, wherein the source of the switch Q2 is connected to the negative input terminal of the dc power supply, and the drain of the switch Q2 is connected to the primary transformer of the dc power supply.
In an embodiment of the present invention, the driving circuit includes a driving chip U4, wherein a driving pin of the driving chip U4 is connected to the gate of the switching tube Q2, a detection pin of the driving chip U4 is connected to the common terminal of the fifth resistor R5 and the sixth resistor R6, and the other end of the sixth resistor R6 is connected to the GND terminal.
The utility model has the advantages that:
1. the utility model discloses an external power supply's mode is the protection circuit power supply, and sampling circuit and input circuit keep apart, guarantee electric safety.
2. The utility model discloses a controllable accurate steady voltage source and resistance are as reference circuit, when setting up the overvoltage point, and accessible benchmark chip and resistance carry out accurate excessive pressure point design.
3. The utility model discloses a enhancement mode NMOS pipe makes the circuit have the self-resuming function as switch tube control power supply circuit, and after the excessive pressure trouble takes place, the switch tube turn-offs, and circuit output voltage falls to zero, and the back is relieved to the excessive pressure trouble, and drive circuit drive switch tube normally works, and circuit automatic recovery is normal.
The present invention will be described in further detail with reference to the accompanying drawings and examples.
Drawings
Fig. 1 is a schematic structural diagram of an output overvoltage protection circuit of a dc power supply according to an embodiment of the present invention;
fig. 2 is an example diagram of an overvoltage protection circuit for a dc power supply according to an embodiment of the present invention.
Detailed Description
The present invention will be described in further detail with reference to specific examples, but the present invention is not limited thereto.
Example one
Referring to fig. 1, fig. 1 is a schematic structural diagram of a dc power output overvoltage protection circuit according to an embodiment of the present invention.
The embodiment of the utility model provides a DC power supply output overvoltage crowbar, include: the circuit comprises a reference circuit, a sampling circuit, a comparison circuit, an isolation conversion circuit and a driving circuit.
The reference circuit is used for acquiring overvoltage protection point information.
Before the circuit is powered on, an overvoltage protection point is designed through a reference circuit.
The sampling circuit is connected to the output positive end and the output negative end of the direct current power supply and used for acquiring and processing output voltage information of the direct current power supply to obtain sampling information.
After the circuit is electrified, the sampling circuit collects the output voltage of the direct current power supply and converts the output voltage into an equal proportion to be input into the comparison circuit. The reference circuit also inputs overvoltage protection point information to the comparison circuit.
The comparison circuit is connected with the reference circuit and the sampling circuit and used for receiving and processing the overvoltage protection point information and the sampling information to obtain a comparison signal.
And the comparison circuit compares the sampling information with the overvoltage protection point information after receiving the sampling information and the overvoltage protection point information, and outputs a corresponding voltage value, namely a comparison signal, according to the ratio of the sampling information to the overvoltage protection point information. When an overvoltage fault occurs, the ratio of the sampling information to the overvoltage protection point information is greater than 1, and the comparison circuit outputs high voltage; and after the overvoltage fault is removed, the ratio of the sampling information to the overvoltage protection point information is less than 1, and the comparison circuit outputs low voltage.
The isolation conversion circuit is connected with the comparison circuit and used for receiving and processing the comparison signal to obtain a conversion signal.
When the comparison signal received by the isolation conversion circuit is high voltage, a high-voltage conversion signal is obtained through conversion; when the comparison signal received by the isolation conversion circuit is low voltage, the low voltage conversion signal is obtained through conversion.
The drive circuit is connected with the isolation conversion circuit and used for receiving the conversion signal and outputting a drive signal corresponding to the conversion signal.
When the drive circuit receives the high-voltage conversion signal, the high-voltage drive signal is output to turn off the switch tube, so that the purpose of overvoltage protection is achieved; when the drive circuit receives the conversion signal of low voltage, the drive signal drives the switching tube to normally work, so as to achieve the purpose of recovering the work of the power supply.
Example two
Referring to fig. 2, fig. 2 is a diagram illustrating an example of a dc power output overvoltage protection circuit according to an embodiment of the present invention.
In this embodiment, the reference circuit includes a voltage regulator U1 and a first resistor R1, where the voltage regulator U1 may be a TL431 controllable precision voltage regulator. The cathode of the voltage-stabilizing source U1 is connected with the resistor R1, the anode of the voltage-stabilizing source U1 is connected with the SGND end, and the reference electrode and the cathode of the voltage-stabilizing source U1 are in short circuit.
In this embodiment, the sampling circuit includes a second resistor R2 and a third resistor R3, wherein the second resistor R2 is connected to the positive output terminal of the dc power supply, and the third resistor R3 is connected to the second resistor R2 and the negative output terminal of the dc power supply.
In this embodiment, the comparison circuit includes an operational amplifier U2. Wherein U2 may be an LM358 dual operational amplifier. The inverting input end of the operational amplifier U2 is connected with the reference electrode of the voltage-stabilizing source U1, the non-inverting input end of the operational amplifier U2 is connected with the common end of the second resistor R2 and the third resistor R3, the negative voltage power supply end of the operational amplifier U2 is connected with the SGND end, and the power supply end of the operational amplifier U2 is connected with the power supply VCC 2.
In this embodiment, the isolation conversion circuit includes a fourth resistor R4, a photocoupler U3, a transistor Q1, a fifth resistor R5, a sixth resistor R6, and a seventh resistor R7. The transistor Q1 may be an NPN transistor FMMT 458; the fourth resistor R4 is connected in parallel with two ends of a light emitting diode of the photoelectric coupler U3, a collector of the photoelectric coupler U3 is connected with a collector of the triode Q1 and a power source VCC1, an emitter of the photoelectric coupler U3 is connected with a base of the triode Q1, the fifth resistor R5 is connected with the emitter of the triode Q1 and the sixth resistor R6, and the other end of the sixth resistor R6 is connected with a GND end. The seventh resistor R7 is connected between the anode of the led of the photocoupler U3 and the output terminal of the operational amplifier U2.
In this embodiment, the isolation conversion circuit further includes a diode D1, the anode of the diode D1 is connected to the seventh resistor R7, and the cathode of the diode D1 is connected to the anode of the light emitting diode of the photocoupler U3.
In this embodiment, the dc power over-voltage protection circuit further includes a switch Q2, wherein the switch Q2 may be an enhancement NMOS transistor, such as IRF 460. The source electrode of the switching tube Q2 is connected with the input negative terminal of the direct current power supply, and the drain electrode of the switching tube Q2 is connected with the primary side of the transformer of the direct current power supply.
In the present embodiment, the driving circuit includes a driving chip U4. The driving chip U4 may be a switching power supply pwm control chip TL 494; a driving pin of the driving chip U4 is connected to the gate of the switching tube Q2, a detection pin of the driving chip U4 is connected to a common terminal of the fifth resistor R5 and the sixth resistor R6, and the other end of the sixth resistor R6 is connected to a GND terminal.
The utility model provides an among the direct current power supply overvoltage crowbar, the power supply VCC1 of input can be realized by the outside power supply of connecting in addition, and output fault detection's power VCC2 also can be realized by the outside power supply of connecting in addition, and two power supply circuit's basic requirement keeps electrical isolation, can guarantee electrical safety like this.
The utility model provides a direct current power supply circuit still includes rectification energy storage circuit, and the primary function is rectification filtering to convey the output of the energy of storage to the power.
The utility model provides an overvoltage protection circuit theory of operation as follows:
before the direct current power supply is used, an overvoltage point is set through a reference circuit. After the circuit is powered on, the direct current power supply starts to work. The reference circuit inputs overvoltage point information, namely reference voltage, to a pin 6, namely an inverting input terminal, of the operational amplifier U2, and the sampling circuit inputs voltage information obtained by dividing the voltage of R2 and R3 to a pin 5, namely a non-inverting input terminal, of the operational amplifier U2.
Before the overvoltage fault occurs to the circuit, the voltage of a pin 5 of the operational amplifier U2 of the comparison circuit is smaller than the voltage of a pin 6, and a pin 7 of the output pin of the operational amplifier U2 outputs low level; the diode D1 is not conducted, the anode of the photoelectric coupler U3 in the isolation conversion circuit is at a low level, the light emitting diode of the photoelectric coupler U3 is not conducted, no current flows between the collector and the emitter of the photoelectric coupler U3, no current flows into the base of the triode Q1, and the Q1 works in a cut-off region; the detection pin 4 of the driving chip U4 in the driving circuit is at low level, the driving pin GATE of the driving chip works normally, and the circuit outputs voltage normally.
When the line has an overvoltage fault, the voltage obtained by dividing the voltage by the R2 and the R3 in the sampling circuit is higher than the reference voltage generated by the reference circuit, the voltage of the pin 5 of the operational amplifier U2 is higher than the voltage of the pin 6, and the pin 7 of the output pin of the operational amplifier U2 outputs high level; the diode D1 is turned on, the anode of the photoelectric coupler U3 in the isolation conversion circuit is at a high level, the light emitting diode of the photoelectric coupler U3 is turned on, and a current flows between the collector and the emitter of the photoelectric coupler U3. The base of the triode Q1 has current flowing in, and Q1 works in an amplification region; a pin 4 of a driving chip U4 in the driving circuit is at a high level, a driving pin GATE of the chip is turned off, a switch tube Q2 is turned off, the circuit has no output voltage, and the purpose of overvoltage protection is achieved.
When the line overvoltage fault is relieved, the voltage of a pin 5 of the operational amplifier U2 of the comparison circuit is smaller than the voltage of a pin 6, and a pin 7 of the output pin of the operational amplifier U2 outputs low level; the anode of the photoelectric coupler U3 in the isolation conversion circuit is at low level, the light emitting diode of the photoelectric coupler U3 is not conducted, no current flows between the collector and the emitter of the photoelectric coupler U3, no current flows into the base of the triode Q1, and the Q1 works in a cut-off region; the detection pin 4 of the driving chip U4 in the driving circuit is at low level, the driving pin GATE of the driving chip drives the switching tube Q2 to work normally, and the circuit is recovered to normal.
The utility model provides a direct current power supply overvoltage crowbar is put by benchmark chip, triode, opto-coupler and fortune and is constituteed, and the power supply and the output fault detection power of input realize by the outside power supply of connecting in addition, have the advantage that can accurately set up overvoltage protection point, good electrical safety performance and self-resuming function. When the overvoltage fault occurs to the circuit, the actually measured voltage is compared with the reference, and then the operational amplifier outputs a corresponding voltage value according to the ratio of the actually measured voltage to the reference. The output voltage of the operational amplifier is transmitted to the primary side through the optocoupler, the overvoltage protection function is realized through the functional pin of the primary side chip, and after the overvoltage fault is relieved, the circuit automatically recovers to be normal. The foregoing is a more detailed description of the present invention, taken in conjunction with the specific preferred embodiments thereof, and it is not intended that the invention be limited to the specific embodiments shown and described. To the utility model belongs to the technical field of ordinary technical personnel, do not deviate from the utility model discloses under the prerequisite of design, can also make a plurality of simple deductions or replacement, all should regard as belonging to the utility model discloses a protection scope.
Claims (8)
1. A dc power supply output overvoltage protection circuit, comprising:
the reference circuit is used for acquiring overvoltage protection point information;
the sampling circuit is connected to the output positive end and the output negative end of the direct-current power supply and used for acquiring and processing output voltage information of the direct-current power supply to obtain sampling information;
the comparison circuit is connected with the reference circuit and the sampling circuit and is used for receiving and processing the overvoltage protection point information and the sampling information to obtain a comparison signal;
the isolation conversion circuit is connected with the comparison circuit and used for receiving and processing the comparison signal to obtain a conversion signal;
and the driving circuit is connected with the isolation conversion circuit and used for receiving the conversion signal and outputting a driving signal corresponding to the conversion signal.
2. The direct current power supply output overvoltage protection circuit according to claim 1, wherein the reference circuit comprises a voltage regulator U1 and a first resistor R1, wherein the cathode of the voltage regulator U1 is connected to the resistor R1, the anode of the voltage regulator U1 is connected to an SGND terminal, and the reference electrode and the cathode of the voltage regulator U1 are shorted.
3. The DC power supply output overvoltage protection circuit as claimed in claim 2, wherein the sampling circuit comprises a second resistor R2 and a third resistor R3, wherein the second resistor R2 is connected to the positive output terminal of the DC power supply, and the third resistor R3 is connected to the second resistor R2 and the negative output terminal of the DC power supply.
4. The DC power supply output overvoltage protection circuit according to claim 3, wherein the comparison circuit comprises an operational amplifier U2, wherein an inverting input terminal of the operational amplifier U2 is connected to a reference electrode of the regulated power supply U1, a non-inverting input terminal of the operational amplifier U2 is connected to a common terminal of the second resistor R2 and the third resistor R3, a negative voltage power supply terminal of the operational amplifier U2 is connected to an SGND terminal, and a power supply terminal of the operational amplifier U2 is connected to a power supply VCC 2.
5. The DC power output overvoltage protection circuit of claim 4, wherein the isolation conversion circuit comprises a fourth resistor R4, a photocoupler U3, a triode Q1, a fifth resistor R5, a sixth resistor R6 and a seventh resistor R7, wherein the fourth resistor R4 is connected in parallel with two ends of a light emitting diode of the photocoupler U3, a collector of the photocoupler U3 is connected with a collector of the triode Q1 and a power supply VCC1, an emitter of the photocoupler U3 is connected with a base of the triode Q1, the fifth resistor R5 is connected with an emitter of the triode Q1 and the sixth resistor R6, the other end of the sixth resistor R6 is connected with a GND terminal, and the seventh resistor R7 is connected between a positive electrode of the light emitting diode of the photocoupler U3 and an output terminal of the operational amplifier U2.
6. The DC power output overvoltage protection circuit as claimed in claim 5, wherein the isolation conversion circuit further comprises a diode D1, the anode of the diode D1 is connected to the seventh resistor R7, and the cathode of the diode D1 is connected to the anode of the LED of the photocoupler U3.
7. The DC power supply output overvoltage protection circuit according to claim 5, further comprising a switch Q2, wherein the source of the switch Q2 is connected to the negative input terminal of the DC power supply, and the drain of the switch Q2 is connected to the primary of the transformer of the DC power supply.
8. The direct current power supply output overvoltage protection circuit according to claim 7, wherein the driving circuit comprises a driving chip U4, wherein a driving pin of the driving chip U4 is connected to the gate of the switching tube Q2, a detection pin of the driving chip U4 is connected to a common terminal of the fifth resistor R5 and the sixth resistor R6, and the other terminal of the sixth resistor R6 is connected to a GND terminal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920440480.1U CN210468787U (en) | 2019-04-02 | 2019-04-02 | Direct current power supply output overvoltage protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920440480.1U CN210468787U (en) | 2019-04-02 | 2019-04-02 | Direct current power supply output overvoltage protection circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN210468787U true CN210468787U (en) | 2020-05-05 |
Family
ID=70428836
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201920440480.1U Active CN210468787U (en) | 2019-04-02 | 2019-04-02 | Direct current power supply output overvoltage protection circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN210468787U (en) |
-
2019
- 2019-04-02 CN CN201920440480.1U patent/CN210468787U/en active Active
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN202373957U (en) | Over-voltage and under-voltage protection circuit | |
| CN101877545B (en) | Power module | |
| CN103457244B (en) | A kind of DC/DC power protecting circuit | |
| WO2019169904A1 (en) | Low-cost input anti-overvoltage protection circuit | |
| CN107845998B (en) | Input power supply health detection and management circuit in power supply parallel redundancy system | |
| CN205453099U (en) | Sampling circuit and mistake, undervoltage protection control circuit | |
| CN105610129A (en) | Sampling circuit and overvoltage and under-voltage protection control circuit | |
| CN219997194U (en) | Power supply abnormality detection circuit, power supply circuit, and monitoring device | |
| CN216086450U (en) | Distribution switch circuit who possesses current sampling and voltage sampling | |
| CN211508593U (en) | Over-current and over-voltage self-locking protection circuit and adapter | |
| CN212518378U (en) | High-precision input overvoltage protection circuit | |
| CN210468787U (en) | Direct current power supply output overvoltage protection circuit | |
| CN210350788U (en) | Power polarity protection circuit | |
| CN104852563A (en) | Switching power supply external soft start circuit | |
| CN202930915U (en) | Short circuit protection device of frequency converter switch power supply | |
| CN209104785U (en) | A kind of current foldback circuit | |
| CN214412260U (en) | High-precision overcurrent short-circuit protection circuit | |
| CN217848945U (en) | Self-locking type high-power SiC MOS tube overcurrent protection circuit | |
| CN112630505B (en) | Wide-voltage self-adaptive high-isolation voltage detection circuit and detection method thereof | |
| CN109449880A (en) | A kind of high-power aerospace modular power source input undervoltage protection circuit | |
| CN109327010B (en) | Electronic fuse circuit | |
| CN109149523B (en) | Self-recovery type overcurrent protection circuit | |
| CN112751410A (en) | Power supply control circuit of low-voltage direct-current circuit | |
| CN214256696U (en) | LED load protection circuit based on BOOST drive | |
| CN112186722B (en) | Circuit with current limiting locking function |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant |