CN210007375U - switching power supply overvoltage protection circuit - Google Patents
switching power supply overvoltage protection circuit Download PDFInfo
- Publication number
- CN210007375U CN210007375U CN201921151313.1U CN201921151313U CN210007375U CN 210007375 U CN210007375 U CN 210007375U CN 201921151313 U CN201921151313 U CN 201921151313U CN 210007375 U CN210007375 U CN 210007375U
- Authority
- CN
- China
- Prior art keywords
- chip
- resistor
- terminal
- overvoltage protection
- power supply
- 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.)
- Expired - Fee Related
Links
- 238000006243 chemical reaction Methods 0.000 claims abstract description 23
- 230000008878 coupling Effects 0.000 claims description 36
- 238000010168 coupling process Methods 0.000 claims description 36
- 238000005859 coupling reaction Methods 0.000 claims description 36
- 239000003990 capacitor Substances 0.000 claims description 13
- 230000005693 optoelectronics Effects 0.000 claims 4
- 238000002955 isolation Methods 0.000 description 6
- 230000000694 effects Effects 0.000 description 3
- 238000001514 detection method Methods 0.000 description 2
- 230000009977 dual effect Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000001914 filtration Methods 0.000 description 2
- 230000003287 optical effect Effects 0.000 description 2
- 230000007547 defect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 230000003014 reinforcing effect Effects 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
Landscapes
- Dc-Dc Converters (AREA)
Abstract
switching power supply overvoltage protection circuit, including DC/DC conversion chip, overvoltage protection module (U4) and feedback circuit, DC/DC conversion chip input termination direct current voltage, by the output required voltage of DC/DC conversion chip, the feedback input end of DC/DC conversion chip is connected with feedback circuit, and the soft start control end of DC/DC conversion chip is connected with overvoltage protection module (U4).
Description
Technical Field
The utility model relates to a switching power supply overvoltage protection technical field, concretely relates to kinds of switching power supply overvoltage crowbar.
Background
With the development of science and technology, the switching power supply is now a mainstream product of a voltage-stabilized power supply and is widely applied to fields of families, military, aviation, vehicles and the like.
At present, the overcurrent, overvoltage and short-circuit protection technology of a switching power supply is mature, and the overvoltage and short-circuit protection scheme in the traditional sense adopted by most products is a mode of realizing overvoltage protection only through a voltage detection end of an MOS (metal oxide semiconductor) driving chip, so that the defects of single protection mode , poor stability, poor electromagnetic compatibility and the like exist.
SUMMERY OF THE UTILITY MODEL
The utility model discloses solve the excessive pressure short-circuit protection scheme in the traditional meaning and have that protection mode is single , stability is relatively poor, electromagnetic compatibility is relatively poor scheduling problem, through providing switching power supply overvoltage crowbar, realize the dual voltage protect function, this circuit interference killing feature is strong moreover, electromagnetic compatibility is good, and is with low costs, and the reliability is high.
The utility model adopts the following technical scheme:
for solving the technical problem, the utility model provides an switching power supply overvoltage crowbar, including DC/DC conversion chip, overvoltage protection module and feedback circuit, DC/DC conversion chip input termination direct current voltage, direct current voltage are exported by the output of DC/DC conversion chip after inside level conversion, feedback circuit is connected to DC/DC conversion chip's feedback input end, overvoltage protection module is connected to DC/DC conversion chip's soft start control end, overvoltage protection module gives DC/DC conversion chip's soft start control end to overvoltage, normal and the level signal that undervoltage signal output corresponds that detects.
According to the kinds of switching power supply overvoltage protection circuits, the DC/DC conversion chip comprises an L4970A chip, and the output end of the L4970A chip is connected to the second photoelectric coupling first, and then the second photoelectric coupling outputs the direct current voltage to play a role in isolation.
In the switching power supply overvoltage protection circuits, the output terminal of the L4970A chip is connected to the emitter of the photo-coupler, the collector of the photo-coupler is connected to the VCC and the terminal of the second capacitor, and the other terminal of the second capacitor is grounded to perform a filtering function.
The switching power supply overvoltage protection circuits comprise a photoelectric coupling and a reference chip, wherein the output voltage of the L4970A chip is connected to a reference voltage circuit formed by the reference chip, the reference voltage circuit is connected to a photoelectric coupling, finally the photoelectric coupling is connected to the feedback input end of the L4970A chip, and the feedback circuit adopts photoelectric coupling to play an isolation role.
The kinds of switch power supply overvoltage protection circuits are characterized in that the reference voltage circuit is composed of a reference chip and a plurality of resistors, the anode of the reference chip and the end of the fifth resistor are connected to the negative pole in a common mode, the cathode of the reference chip is connected to the 0 end of the second resistor, the other end of the second resistor is connected to the end of the th resistor, the other end of the th resistor and the end of the third resistor are connected to the positive pole in a common mode, and the other end of the third resistor is connected to the other end of the fifth resistor.
According to the kinds of switching power supply overvoltage protection circuits, a resistance-capacitance branch is connected in parallel between the cathode and the base of the reference chip, and a fourth resistor and a capacitor are connected in series to form the resistance-capacitance branch, so that the electromagnetic compatibility of the circuit is enhanced.
In the kinds of overvoltage protection circuits for the switching power supply, the collector of the th photoelectric coupling is connected to the feedback input end of the L4970A chip, the emitter of the th photoelectric coupling is grounded, the anode of the th photoelectric coupling is connected to the connection between the th resistor and the second resistor, and the cathode of the th photoelectric coupling is connected to the cathode of the reference chip.
In the kinds of switching power supply overvoltage protection circuits, the voltage detected by the overvoltage protection module is the voltage between the positive electrode and the negative electrode, and the detection mode is not limited.
In the switching power supply overvoltage protection circuits, the reference chip adopts TL431, the reference voltage is 1.24V, and the th photoelectric coupling and the second photoelectric coupling adopt P721F.
The utility model discloses an effect and effect:
the utility model discloses not only realized the power overvoltage output protection in the traditional meaning, still adopted duplicate protection to combine together feedback protection and overvoltage protection promptly to optimize the circuit, thereby improved switching power supply module's efficiency and protection circuit's stability, accuracy, all adopted the isolation when designing circuit feedback and excessive pressure simultaneously, makeed power supply interference killing feature advance step enhancement.
Drawings
The aspects and advantages of the present application will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention.
In the drawings:
FIG. 1 is a specific circuit diagram of types in this embodiment 1;
the components represented by the reference numerals in the figures are:
the protection circuit comprises a U1 chip, an L4970A chip, a U2 chip, a photoelectric coupling chip, a U3 chip, a second photoelectric coupling chip, a U4 chip, an overvoltage protection module, an R1 chip, a resistor, an R2 chip, a second resistor, an R3 chip, a third resistor, an R4 chip, a fourth resistor, an R5 chip, a fifth resistor, an R6 chip, a sixth resistor, a D1 chip, a reference chip, a C1 chip, a capacitor, a C2 chip, a second capacitor, VCC, a power supply, GND, ground, OUT1 chip, a positive electrode, OUT2 chip and a negative electrode.
Detailed Description
Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. It should be noted that these embodiments are provided so that this disclosure can be more completely understood and fully conveyed to those skilled in the art, and the present disclosure may be implemented in various forms without being limited to the embodiments set forth herein.
Example 1
Referring to fig. 1, fig. 1 shows an kinds of switching power supply overvoltage protection circuits of this embodiment, including a DC/DC conversion chip, preferably, the DC/DC conversion chip is a chip with a model number of L4970A, a feedback input terminal pin 11 of the L4970A chip U1 is connected to a feedback circuit, a soft start control terminal pin 12 of the L4970A chip U1 is connected to an overvoltage protection module U4, so as to implement dual protection, that is, overvoltage protection and feedback protection are combined, an input terminal of the L4970A chip U1 is connected to a direct current voltage, the direct current voltage is subjected to level conversion in the L4970A chip U1 to obtain a required voltage value, and the converted voltage is output from an output terminal pin 7 of the L4970A chip U1.
And , the pin 7 of the output end of the U1 of the L4970A chip is connected to a second photoelectric coupling U3, and then the second photoelectric coupling U3 outputs direct-current voltage, and the anti-jamming capability of the circuit can be improved by adopting optical coupling isolation.
With reference to fig. 1, an output terminal pin 7 of the L4970A chip U1 is connected to an emitter terminal pin 3 of the photoelectric coupling U3, a collector terminal pin 4 of the photoelectric coupling U3 is connected to a VCC power supply and a terminal of the second capacitor C2, the other terminal of the second capacitor C2 is grounded, filtering is performed by the second capacitor C2 to prevent high-frequency interference, an anode terminal 1 of the second photoelectric coupling U3 is connected in series with a sixth resistor R6 to serve as an anode OUT1 of a final output voltage, a cathode terminal 2 of the second photoelectric coupling U3 serves as a cathode OUT2 of the final output voltage, the anode OUT1 and the cathode OUT2 are connected to an electric appliance, and the overvoltage protection module U4 directly or indirectly detects a voltage between the anode OUT1 and the cathode OUT2 and converts the detected voltage into a level signal to be input to a soft start control terminal pin 12 of the L4970A chip U1.
The feedback circuit comprises an photoelectric coupling U2 and a reference chip D1, the output voltage of the L4970A chip U1 is connected to a reference voltage circuit formed by a reference chip D1, the reference voltage circuit is connected to an photoelectric coupling U2, and a photoelectric coupling U2 is connected to the feedback input end of the L4970A chip U1.
The reference voltage circuit comprises a reference chip and a plurality of resistors, wherein the anode of the reference chip D1 and the end of the fifth resistor R5 are connected to the negative OUT2 in common, the cathode of the reference chip D1 is connected to the end of the second resistor R2, the other end of the second resistor R2 is connected to the end of the resistor R1, the other end of the resistor R1 and the end of the third resistor R3 are connected to the positive OUT1 in common, and the other end of the third resistor R3 is connected to the other end of the fifth resistor R5.
And a resistor-capacitor series branch is connected between the cathode and the base of the reference chip D1 and is formed by connecting a fourth resistor R4 and a capacitor C1 in series, and the branch is added to enhance the electromagnetic compatibility of the reference voltage circuit.
The collector pin 4 of the photoelectric coupling U2 is connected with the feedback input end pin 11 of the L4970A chip U1, the emitter pin 3 of the photoelectric coupling U2 is grounded, the anode pin 1 of the photoelectric coupling U2 is connected with the joint of the resistor R1 and the second resistor R2, the cathode pin 2 of the photoelectric coupling U2 is connected with the cathode of the reference chip D1, and both the output and the feedback adopt optical coupling isolation to protect the chip and improve the anti-interference capability of the circuit.
The photoelectric couplings U2 and U3 adopt P721F; the reference chip D1 adopts TL431, and the reference voltage is 1.24V; the resistor R1-R2-4.7 k Ω, R4-2.4 k Ω, R3-2.1 k Ω, R5-1.7 k Ω, and R6-100 Ω; the capacitance C1 ═ 1 μ F and the capacitance C2 ═ 0.01 μ F.
The utility model discloses a theory of operation does:
the utility model adopts the combination of overvoltage protection and feedback protection, when the output voltage exceeds 12V, the overvoltage protection module U4 detects overvoltage, the level of the pin 12 of the soft start control end of the U1 of the L4970A chip is pulled down to 0, and the chip enters an overvoltage protection state; meanwhile, the parallel resistor R2 of the optocoupler U2 in the feedback circuit controls the voltage of the reference chip D1 to be 1.24V, namely the input voltage of the optocoupler U2 is clamped to be 1.24V, so that the voltage of a feedback input end pin 11 of the L4970A chip U1 is 0, the output voltage of the L4970A chip U1 is limited, and the protection effect is achieved.
If a negative voltage is output, the optocoupler U3 has no voltage signal, and the voltage of the 12 pin of the L4970A chip U1 is equal to 0 at this time, and the power supply is in a protection (overvoltage and feedback protection) state.
The utility model discloses not only realized the power overvoltage output protection in the traditional meaning, overvoltage protection adopts duplicate protection promptly feedback protection and overvoltage protection combine together moreover to improve the accuracy and the stability of protection, improved switching power supply module's efficiency, all adopted the isolation when designing circuit feedback and excessive pressure simultaneously, makeed the power interference killing feature reinforcing, increased electric capacity C1, strengthened the electromagnetic compatibility of circuit.
The above description is only a preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention should be covered by the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (9)
- The overvoltage protection circuit of the switching power supply comprises a DC/DC conversion chip, wherein the input end of the DC/DC conversion chip is connected with direct-current voltage, and the direct-current voltage is output by the output end of the DC/DC conversion chip after internal level conversion, and the overvoltage protection circuit is characterized in that the feedback input end of the DC/DC conversion chip is connected with a feedback circuit, and the soft start control end of the DC/DC conversion chip is connected with an overvoltage protection module (U4).
- 2. The kinds of switch power supply overvoltage protection circuit according to claim 1, wherein the DC/DC conversion chip includes an L4970A chip (U1), the output terminal of the L4970A chip (U1) is first connected to the second photoelectric coupling (U3), and then the second photoelectric coupling (U3) outputs the DC voltage.
- 3. The kinds of switch power supply overvoltage protection circuit according to claim 2, wherein the output terminal of the L4970A chip (U1) is connected to the emitter of the second photo-coupler (U3), the collector of the photo-coupler (U3) is connected to the VCC and the terminal of the second capacitor (C2), the other terminal of the second capacitor (C2) is grounded, the anode of the second photo-coupler (U3) is connected in series with the sixth resistor (R6) to be the positive electrode (OUT1) of the final output voltage, and the cathode of the second photo-coupler (U3) is used as the negative electrode (OUT2) of the final output voltage.
- 4. The kinds of switch power supply overvoltage protection circuit according to claim 2, wherein the feedback circuit includes photo-couple (U2) and reference chip (D1), the output voltage of the L4970A chip (U1) is connected to the reference voltage circuit formed by the reference chip (D1), and then is connected to photo-couple (U2) by the reference voltage circuit, and photo-couple (U2) is connected to the feedback input terminal of the L4970A chip (U1).
- 5. The kind of switch power supply overvoltage protection circuit according to claim 4, wherein the reference voltage circuit further includes several resistors, the anode of the reference chip (D1) and the terminal of the fifth resistor (R5) are connected to the cathode (OUT2), the cathode of the reference chip (D1) is connected to the 0 terminal of the second resistor (R2), the other terminal of the second resistor (R2) is connected to the terminal of the resistor (R1), the other terminal of the resistor (R1) and the terminal of the third resistor (R3) are connected to the anode (OUT1), and the other terminal of the third resistor (R3) is connected to the other terminal of the fifth resistor (R5).
- 6. The kind of switch power supply overvoltage protection circuit according to claim 5, wherein the resistance-capacitance series branch is connected between the cathode and the base of the reference chip (D1), and the resistance-capacitance series branch is formed by connecting the fourth resistor (R4) and the capacitor (C1) in series.
- 7. The kinds of switch power supply overvoltage protection circuit according to claim 4, wherein the collector of th opto-electronic coupling (U2) is connected to the feedback input terminal of the L4970A chip (U1), the emitter of th opto-electronic coupling (U2) is grounded, the anode of th opto-electronic coupling (U2) is connected to the junction of th resistor (R1) and the second resistor (R2), and the cathode of th opto-electronic coupling (U2) is connected to the cathode of the reference chip (D1).
- 8. The kinds of switch power supply over-voltage protection circuit of claim 3, wherein the over-voltage protection module (U4) detects the voltage between the positive pole (OUT1) and the negative pole (OUT 2).
- 9. The switching power supply overvoltage protection circuit according to claim 4, wherein the reference chip (D1) adopts TL431, and the reference voltage is 1.24V.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921151313.1U CN210007375U (en) | 2019-07-22 | 2019-07-22 | switching power supply overvoltage protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921151313.1U CN210007375U (en) | 2019-07-22 | 2019-07-22 | switching power supply overvoltage protection circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN210007375U true CN210007375U (en) | 2020-01-31 |
Family
ID=69310820
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201921151313.1U Expired - Fee Related CN210007375U (en) | 2019-07-22 | 2019-07-22 | switching power supply overvoltage protection circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN210007375U (en) |
-
2019
- 2019-07-22 CN CN201921151313.1U patent/CN210007375U/en not_active Expired - Fee Related
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN100574031C (en) | A kind of power convertor output protection circuit | |
| CN213585564U (en) | Switching power supply | |
| CN206389350U (en) | A kind of light-coupled isolation communicating circuit | |
| CN103401401B (en) | Drive circuit for separate type high-power isolated gate bipolar transistor | |
| CN108494262A (en) | The special full isolation DC-DC converter of New-energy electric vehicle | |
| CN203674974U (en) | Circuit for enhancing power supply impacting and interference resistance properties of power-take switch | |
| CN101924459B (en) | Switching signal interface circuit based on double photoelectric isolation | |
| CN210007375U (en) | switching power supply overvoltage protection circuit | |
| CN209559340U (en) | A kind of temperature protection and alarm circuit | |
| CN201860094U (en) | Short circuit protection circuit for switch power | |
| CN209282826U (en) | A kind of overcurrent protection circuit of display module | |
| CN106100128B (en) | Monitoring device is isolated in active power distribution network intelligent terminal accumulator | |
| CN210273822U (en) | High-efficient safe anti-interference IGBT drive circuit | |
| CN205283507U (en) | Direct -current solid -state relay | |
| CN208782794U (en) | Isolation circuit and electronic equipment | |
| CN209992839U (en) | Analog input switching circuit | |
| CN209198534U (en) | A kind of zero cross detection circuit and device | |
| CN208508797U (en) | The dedicated full isolation DC-DC converter of New-energy electric vehicle | |
| CN208156447U (en) | A kind of high anti-interference electron pressure control power supply | |
| CN213213422U (en) | Direct current input switching value acquisition circuit and direct current switching value acquisition device | |
| CN210985643U (en) | Motor overvoltage protection circuit and motor | |
| CN106647492A (en) | Alternating-current switching value signal acquisition circuit | |
| CN215990564U (en) | Optimized EMC circuit for switching power supply | |
| CN217332739U (en) | Relay contact state detection circuit | |
| CN220822915U (en) | Bidirectional DC/DC control circuit system and device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20200131 |