CN206442106U - A kind of overvoltage crowbar for Switching Power Supply - Google Patents
A kind of overvoltage crowbar for Switching Power Supply Download PDFInfo
- Publication number
- CN206442106U CN206442106U CN201720076689.5U CN201720076689U CN206442106U CN 206442106 U CN206442106 U CN 206442106U CN 201720076689 U CN201720076689 U CN 201720076689U CN 206442106 U CN206442106 U CN 206442106U
- Authority
- CN
- China
- Prior art keywords
- resistance
- switch controller
- voltage
- power supply
- turned
- 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
Landscapes
- Emergency Protection Circuit Devices (AREA)
Abstract
The utility model provides a kind of overvoltage crowbar for Switching Power Supply, including：Sample circuit, logic control circuit, return difference circuit；The input of the sample circuit is connected with power supply；The output end of the sample circuit is connected with the output end of the logic control circuit；One end of the return difference circuit is connected on sample circuit, and the other end is connected on logic control circuit；The return difference circuit is used to be controlled the scope of the critical voltage of the overvoltage crowbar, and the logic control circuit is used for turning on and off for controlling switch power supply.The return difference circuit can be used for being controlled the scope of the critical voltage of the overvoltage crowbar, and the overvoltage crowbar can avoid the Switching Power Supply caused by input voltage shakiness from frequently opening the unstable state of shut-off.
Description
Technical field
The utility model is related to a kind of overvoltage crowbar, and in particular to a kind of overvoltage protection electricity for Switching Power Supply
Road.
Background technology
Switching Power Supply is to utilize modern power electronics technology, the time ratio that controlling switch pipe is turned on and off, and remains steady
Determine a kind of power supply of output voltage, Switching Power Supply is widely used in industrial automatic control, military industry equipment, research equipment, LED and shone
Bright, industrial control equipment, communication apparatus, power equipment, instrument and meter, Medical Devices and semiconductor refrigerating such as heat at the field.
In Switching Power Supply, because its input input voltage is unstable, voltage pulsation is larger, if input voltage mistake
Greatly, it is likely that cause its switching tube excessive by electric current, and then burn switching tube.Therefore in the control circuit of switching tube power supply
In generally include overvoltage crowbar, the effect of overvoltage crowbar is in the super switching off in limited time master chip of input terminal voltage
Power supply, makes circuit be stopped with protection switch power supply.
Overvoltage protection is inputted currently for Switching Power Supply, the circuit mainly applied is directly to use voltage reference chip conduct
Sampling and control section, it is simple in construction, there are problems that.When input voltage is unstable, ceaselessly increases or reduce suddenly
When, the Switching Power Supply also and then can be opened or turned off, and ceaselessly be switched, in this way it is easy to cause Switching Power Supply or negative
What is carried burns out, and more seriously, can also produce potential safety hazard.
Utility model content
For defect of the prior art, the utility model provides a kind of overvoltage crowbar for Switching Power Supply, with
The unstable state for frequently opening shut-off of the Switching Power Supply caused by voltage instability can be avoided.
The technical solution adopted in the utility model is：
The utility model provides a kind of overvoltage crowbar for Switching Power Supply, including：Sample circuit, logic control electricity
Road, return difference circuit；
The input of the sample circuit is connected with power supply；
The output end of the sample circuit is connected with the output end of the logic control circuit；
One end of the return difference circuit is connected on sample circuit, and the other end is connected on logic control circuit；Described time
Difference circuit is used to be controlled the scope of the critical voltage of the overvoltage crowbar, and the logic control circuit is used to control
Switching Power Supply is turned on and off.
Optionally, the sample circuit, including：First resistor, second resistance and voltage reference chip；
The first end of the first resistor is connected with power supply；
Second end of the first resistor is connected with the first end of the second resistance；
The first end of the second resistance is connected with the reference pole of the voltage reference chip；The second of the second resistance
End is connected with the anode of the voltage reference chip, and is grounded；The negative electrode of the voltage reference chip and logic control electricity
Road is connected；
When the voltage at the second resistance two ends is not less than the reference voltage of the voltage reference chip, the voltage base
Quasi- chip conducting；When the voltage at the second resistance two ends is less than the reference voltage of the voltage reference chip, the voltage
Fiducial chip is not turned on.
Optionally, the logic control circuit, including：3rd resistor, the 4th resistance, the 5th resistance, the 6th resistance；
The first end of the 3rd resistor is connected with built-in power, the second end of the 3rd resistor and the 4th resistance
First end connection；
Second end of the 3rd resistor is connected with the negative electrode of the voltage reference chip, the second end of the 4th resistance
It is connected, and is grounded with the anode of the voltage reference chip；
The first end of 5th resistance is connected with the built-in power, the second end and the described 6th of the 5th resistance
The first end connection of resistance, the second end of the 6th resistance is connected with the second end of the 4th resistance, and is grounded.
Optionally, the logic control circuit, including：First switch controller, second switch controller；
The first switch controller uses NPN triode or N-channel MOS pipe；
The second switch controller uses NPN triode or N-channel MOS pipe.
Optionally, the first switch controller uses NPN triode；
The base stage of the first switch controller is connected with the first end of the 4th resistance；The first switch controller
Colelctor electrode be connected with the second end of the 5th resistance；The emitter stage of the first switch controller and the 4th resistance
Second end is connected, and is grounded；
When the voltage reference chip is turned on, the first switch controller is not turned on；When the voltage reference chip
When being not turned on, the first switch controller conducting.
Optionally, the second switch controller uses NPN triodes；
The base stage of the second switch controller is connected with the first end of the 6th resistance；The second switch controller
Colelctor electrode be connected with control chip；The emitter stage of the second switch controller is connected with the second end of the 6th resistance,
And be grounded；
When the voltage reference chip is turned on, the first switch controller is not turned on, the second switch controller
Conducting, the Switching Power Supply is in guard mode；When the voltage reference chip is not turned on, the first switch controller is led
Logical, the second switch controller is not turned on, and the Switching Power Supply is in normal operating conditions.
Optionally, the logic control circuit, in addition to：First electric capacity；
First electric capacity is connected with the 6th resistor coupled in parallel.
Optionally, the return difference circuit, including：7th resistance, diode；
7th resistance is connected with the Diode series, the positive pole of the diode and the first of the 7th resistance
End connection, the second end of the 7th resistance is connected with the first end of the second resistance, the negative pole of the diode with it is described
The second end connection of 5th resistance；
When the first switch controller is turned on, the return difference circuit turn-on, the return difference circuit is electric with described second
Resistance is in parallel；When the first switch controller is not turned on, the return difference circuit is not turned on.
Optionally, the voltage reference chip is using the accurate adjustable reference source of low-voltage or programmable precision reference source.
Optionally, the sample circuit, in addition to：Second electric capacity；
Second electric capacity is connected in parallel with the second resistance.
The utility model provides a kind of overvoltage crowbar for Switching Power Supply, including：Sample circuit, logic control
Circuit, return difference circuit；The input of the sample circuit is connected with power supply；The output end of the sample circuit and the logic control
The output end of circuit processed is connected；One end of the return difference circuit is connected on sample circuit, and the other end is connected to logic control electricity
Lu Shang；The return difference circuit is used to be controlled the scope of the critical voltage of the overvoltage crowbar, the logic control
Circuit is used for turning on and off for controlling switch power supply.
When the input voltage of the power supply is less than certain critical voltage, the Switching Power Supply is open-minded, in normal work
The state of work；When the input voltage of the power supply is higher than certain critical voltage, the Switching Power Supply shut-off, in protection shape
State.The return difference circuit can be used for being controlled the scope of the critical voltage of the overvoltage crowbar, work as input voltage
Shakiness, when having voltage pulsation, if the fluctuation range of voltage is within the scope of the critical voltage that the return difference circuit is controlled,
The overvoltage crowbar will maintain the current state of the Switching Power Supply；If beyond the scope, the overvoltage protection
The Switching Power Supply will be switched to another state by circuit.Therefore, the overvoltage crowbar can be avoided because of input electricity
The unstable Switching Power Supply caused of pressure frequently opens the unstable state of shut-off.
Brief description of the drawings
, below will be right in order to illustrate more clearly of the utility model embodiment or technical scheme of the prior art
The accompanying drawing used required in embodiment or description of the prior art is briefly described.In all of the figs, it is similar
Element or part are general by similar reference mark.In accompanying drawing, each element or part might not be according to actual ratios
Draw.
A kind of schematic diagram for overvoltage crowbar for Switching Power Supply that Fig. 1 provides for the utility model；
A kind of overvoltage crowbar for Switching Power Supply containing N-channel MOS pipe that Fig. 2 provides for the utility model
Schematic diagram.
Wherein, R1 represents first resistor, and R2 represents second resistance, and R3 represents 3rd resistor, and R4 represents the 4th resistance, R5 tables
Show the 5th resistance, R6 represents the 6th resistance, and R7 represents the 7th resistance, and R8 represents the 8th resistance, and R9 represents the 9th resistance, and HV is represented
Power supply, VCC represents built-in power, and VD1 represents diode, and N1 represents voltage reference chip, and VT1 represents that first switch controller is
NPN triode, VT2 represents that second switch controller is NPN triodes, and VM1 represents that second switch controller is N-channel MOS pipe,
FB represents control chip, and SGND represents ground connection.
Embodiment
Here, it is to be noted that, function, method that the utility model is related to etc. are only the conventional adaptation of prior art
Using.Therefore, the utility model is substantially the annexation between hardware for the improvement of prior art, rather than for work(
Can, method in itself, namely although the utility model is related to some functions, method, but and not comprising being proposed in itself to function, method
Improvement.The utility model, for the description of function, method, is in order to better illustrate the utility model, preferably to manage
Solve the utility model.
The embodiment of technical solutions of the utility model is described in detail below in conjunction with accompanying drawing.Following examples are only
For clearly illustrating the technical solution of the utility model, therefore example is only used as, and this practicality can not be limited with this
New protection domain.
It should be noted that unless otherwise indicated, technical term or scientific terminology used in this application should be this reality
The ordinary meaning understood with new one of ordinary skill in the art.
It refer to Fig. 1, a kind of overvoltage protection electricity for Switching Power Supply that Fig. 1 provides for the utility model specific embodiment
The schematic diagram on road, the overvoltage crowbar for Switching Power Supply that the present embodiment is provided, including：Sample circuit, logic control electricity
Road, return difference circuit.
The input of the sample circuit is connected with power supply；The output end of the sample circuit and the logic control circuit
Output end be connected；One end of the return difference circuit is connected on sample circuit, and the other end is connected on logic control circuit；Institute
Stating return difference circuit is used to be controlled the scope of the critical voltage of the overvoltage crowbar, and the logic control circuit is used for
Controlling switch power supply is turned on and off.
The effect of the overvoltage crowbar is：When the input voltage is less than certain critical voltage, the switch
Power supply is open-minded, the state in normal work；When the input voltage is higher than certain critical voltage, the Switching Power Supply is closed
It is disconnected, in guard mode.The return difference circuit can be used for being controlled the scope of the critical voltage of the overvoltage crowbar,
When input voltage shakiness, when having voltage pulsation, if the critical voltage that the fluctuation range of voltage is controlled in the return difference circuit
Within the scope of, then the overvoltage crowbar will maintain the current state of the Switching Power Supply；If beyond the scope, institute
Another state will be switched to by the Switching Power Supply by stating overvoltage crowbar.Therefore, the overvoltage crowbar can be kept away
Exempt from the unstable state that the Switching Power Supply caused by input voltage shakiness frequently opens shut-off.
In one embodiment that the utility model is provided, the sample circuit can include：First resistor R1, second
Resistance R2 and voltage reference chip N1.
The first end of the first resistor R1 is connected with power supply；The second end of the first resistor R1 and the second resistance
R2 first end connection；The first end of the second resistance R2 is connected with the reference pole of the voltage reference chip N1；Described
Two resistance R2 the second end is connected with the anode of the voltage reference chip N1, and is grounded；The moon of the voltage reference chip N1
Pole is connected with the logic control circuit.
When the voltage at the second resistance R2 two ends is not less than the reference voltage of the voltage reference chip N1, the electricity
Press fiducial chip N1 conductings；When the voltage at the second resistance R2 two ends is less than the reference voltage of the voltage reference chip N1
When, the voltage reference chip N1 is not turned on.
The voltage reference chip N1 can be using the accurate adjustable reference source of low-voltage or programmable precision reference source.As schemed
Shown in 1, the voltage reference chip N1 uses programmable precision reference source (TL431), the programmable precision reference
Source can use 2.5V TL431.
The first resistor R1 is far longer than the second resistance R2, and the resistance sizes of the second resistance R2 are by the electricity
Fiducial chip N1 reference voltage is pressed to determine, the first resistor R1 is used for sharing the high voltage of the power supply output.
In one embodiment that the utility model is provided, the sample circuit can also include：Second electric capacity C2.
The second electric capacity C2 is connected in parallel with the second resistance R2, the voltage that can be exported for the filtering power supply
Small fluctuation, spike of signal etc., can filter out some interference signals in the voltage signal, can avoid the interference
Influence of the signal to the voltage reference chip N1.
In one embodiment that the utility model is provided, the logic control circuit can include：3rd resistor R3,
4th resistance R4, the 5th resistance R5, the 6th resistance R6.
The first end of the 3rd resistor R3 is connected with built-in power VCC, the second end of the 3rd resistor R3 with it is described
4th resistance R4 first end connection；The second end of the 3rd resistor R3 is connected with the negative electrode of the voltage reference chip N1,
The second end of the 4th resistance R4 is connected with the anode of the voltage reference chip N1, and is grounded；The 5th resistance R5's
First end is connected with the built-in power VCC, and the second end of the 5th resistance R5 connects with the first end of the 6th resistance R6
Connect, the second end of the 6th resistance R6 is connected with the second end of the 4th resistance, and is grounded.
The 3rd resistor R3 and built-in power VCC of the 5th resistance R5 connections can be a power supply, can also
It is two different power supplys.
In one embodiment that the utility model is provided, the logic control circuit can also include：First electric capacity
C1。
The first electric capacity C1 is connected in parallel with the 6th resistance R6.It is described that the first electric capacity C1 can be used for filtering
The small fluctuation of the voltage signal of built-in power VCC output and spike, can filter out some interference signals, can avoid institute
State the influence that interference signal is switched on or off to the second switch controller.
In one embodiment that the utility model is provided, the logic control circuit can also include：8th resistance R8
And/or the 9th resistance R9.
The first end of the 8th resistance R8 is connected with the second end of the 3rd resistor R3, and the of the 8th resistance R8
Two ends are connected with the first end of the 4th resistance R4, and the 8th resistance R8 is connected on the 3rd resistor R3 and the described 4th
Between resistance R4；The first end of the 9th resistance R9 is connected with the second end of the 5th resistance R5, the 9th resistance R9
The second end be connected with the first end of the 6th resistance R6, the 9th resistance R9 is connected on the 5th resistance R5 and described
Between 6th resistance R6.The 8th resistance R8 and the 9th resistance R9 can adjust circuit as divider resistance
It is more convenient.
In one embodiment that the utility model is provided, the logic control circuit, including：First switch controller,
Second switch controller.
The first switch controller can use NPN triode or N-channel MOS pipe；The second switch controller can
To use NPN triode or N-channel MOS pipe.
When the first switch controller use NPN triode VT1 when, the base stage of the first switch controller with it is described
4th resistance R4 first end connection；The colelctor electrode of the first switch controller and the second end of the 5th resistance R5 connect
Connect；The emitter stage of the first switch controller is connected with the second end of the 4th resistance R4, and is grounded.Here the 4th electricity
Resistance R4 can also change into be multiple resistance series connection and/or parallel connection, all within protection domain of the present utility model.It is no matter described
How 4th resistance R4 replaces, emitter stage all grounding connections of the first switch controller.
Because the negative electrode of the voltage reference chip is connected with the second end of the 3rd resistor R3, the voltage reference core
The plus earth of piece, so, when the voltage reference chip is turned on, it is possible to drag down the second end of the 3rd resistor R3
Voltage, and then make the voltage reduction of the first end of the 4th resistance R4, low level is produced, the low level is not enough to drive institute
First switch controller is stated, then the first switch controller is not turned on；It is and described when the voltage reference chip is not turned on
Voltage reference chip is compared when turning on, and the first end of the 4th resistance R4 is in high level, and the high level can drive described
First switch controller, then the first switch controller conducting.
When the first switch controller uses N-channel MOS pipe, the connected mode of the first switch controller should
Meet the connected mode of N-channel MOS pipe.
When the second switch controller use NPN triode VT2 when, the base stage of the second switch controller with it is described
6th resistance R6 first end connection；The colelctor electrode of the second switch controller is connected with control chip FB；Described second opens
The emitter stage of gateway controller is connected with the second end of the 6th resistance R6, and is grounded.The control chip FB can be for holding
The operation turned on and off of the row Switching Power Supply.
When the second switch controller uses N-channel MOS pipe VM1, as shown in Fig. 2 the grid of the N-channel MOS pipe VM1
Pole is connected with the first end of the 6th resistance R6, the source electrode of the N-channel MOS pipe VM1 and the second of the 6th resistance R6
End connection, and be grounded, the drain electrode of the N-channel MOS pipe VM1 is connected with control chip FB.
6th resistance R6 described here can be replaced with the series connection and/or parallel connection of multiple resistance, all in the utility model
Protection domain in.No matter how the 6th resistance R6 replaces, emitter stage all grounding connections of the first switch controller.
When the voltage reference chip is not turned on, the first switch controller conducting, due to the first switch control
The grounded emitter of device processed, the resistance very little of the first switch controller, can be with when the first switch controller is turned on
By the voltage pull-down at the second end of the 5th resistance R5, and then by the voltage pull-down of the first end of the 6th resistance R6, make
The first end of the 6th resistance R6 is in low level, and the low level is not enough to drive the second switch controller, then described
Second switch controller is not turned on, and the Switching Power Supply is in normal operating conditions.
When the voltage reference chip is turned on, the first switch controller is not turned on, with the voltage reference chip
Compared when being not turned on, the voltage of the first end of the 6th resistance R6 is in high level, and the high level can drive described second
Switch controller, then the second switch controller conducting, can drive the control chip FB, the Switching Power Supply is broken
Open, circuit is in guard mode.Due to the grounded emitter of the second switch controller, compared to prior art, described second
Switch controller can export a relatively low low level, and then drag down control chip FB control voltage, make circuit in protection
State, by this connected mode, can make the control chip FB with compared with low driving voltage be applied to overvoltage protection electricity
Road, by increasing capacitance it is possible to increase the application of the overvoltage crowbar.
In one embodiment that the utility model is provided, the return difference circuit, including：7th resistance R7, diode
VD1。
The 7th resistance R7 and diode VD1 is connected in series, the positive pole of the diode VD1 and the described 7th electricity
R7 first end connection is hindered, the second end of the 7th resistance R7 is connected with the first end of the second resistance R2, two pole
Pipe VD1 negative pole is connected with the second end of the 5th resistance R5.
In this application, the resistance mentioned can be replaced with the combination of multiple resistance, all in protection of the present utility model
In the range of.
Because the diode VD1 is one-way conduction, when the first switch controller is not turned on, the 5th electricity
The voltage for hindering R5 the second end is in high level, i.e., described diode VD1 negative pole is in high level, so, the return difference circuit is not
Conducting；When the first switch controller is turned on, the voltage at the second end of the 5th resistance R5 is in low level, i.e., described two
Pole pipe VD1 negative pole is in low level, then the return difference circuit turn-on, so make the 7th resistance R7, the diode VD1 and
The circuit of the first switch controller formation is in parallel with the second resistance R2, due to the resistance of the first switch controller
Very little, so, the parallel connection can be regarded to the return difference circuit as in parallel with the second resistance R2；When the return difference circuit
After in parallel with the second resistance R2, when being not turned on compared to the return difference circuit, the voltage at the second resistance R2 two ends is bright
The voltage at second resistance R2 two ends under the aobvious voltage for being less than second resistance R2 two ends when the return difference circuit is not turned on, two states
Difference is exactly hysteresis voltage.
It is described when the fluctuation for the voltage that the input voltage divides on second resistance R2 is in the range of the hysteresis voltage
Overvoltage crowbar will maintain the current state of the Switching Power Supply；The electricity divided when the input voltage on second resistance R2
When the fluctuation of pressure is not in the range of the hysteresis voltage, the Switching Power Supply will be switched to another by the overvoltage crowbar
The state of kind.When the Switching Power Supply switches from working condition to guard mode, the overvoltage crowbar can have return difference electricity
Pressure；When the Switching Power Supply switches from guard mode to working condition, the overvoltage crowbar can also have return difference electricity
Pressure.By this connected mode, can avoid because input voltage is unstable and caused by Switching Power Supply frequently turn on and off not
Stable state；Meanwhile, this connected mode can also improve the precision of the overvoltage crowbar, can avoid the switch electricity
The source erroneous judgement influenced by ambient temperature produced to input voltage, can improve the reliability and stability of the Switching Power Supply.
When the input voltage of the power supply is less than the voltage set, the voltage at the second resistance R2 two ends is less than described
The reference voltage of voltage reference chip, then the voltage reference chip be not turned on；When the voltage reference chip is not turned on, institute
The conducting of first switch controller is stated, the return difference circuit turn-on, the return difference circuit is in parallel with the second resistance R2；By institute
The grounded emitter of first switch controller is stated, can be by the 5th resistance R5 when the first switch controller is turned on
The second end voltage pull-down, and then by the voltage pull-down of the first end of the 6th resistance R6, make the 6th resistance R6's
First end is in low level, and the low level is not enough to drive the second switch controller, then the second switch controller is not
Conducting, the Switching Power Supply is in normal operating conditions.
When the input voltage of the power supply is higher than the voltage set, the voltage at the second resistance R2 two ends is higher than described
The reference voltage of voltage reference chip, then voltage reference chip conducting, when the voltage reference chip is turned on, described the
One switch controller is not turned on, and then, the voltage at the second end of the 5th resistance R5 is in high level, then the return difference circuit is not
Conducting, the voltage of the first end of the 6th resistance R6 is in high level, the second switch controller conducting, can be driven described
Control chip FB, disconnects the Switching Power Supply, and circuit is in guard mode.
It when the input voltage of the power supply is reduced, can be not turned on the voltage reference chip, described return can be started
During difference circuit, the first switch controller conducting, and then, the second switch controller shut-off, the Switching Power Supply is recovered
Output.
More than, a kind of overvoltage crowbar for Switching Power Supply provided for the utility model.
In the description of the present application, it is to be understood that term " first ", " second " etc. are only used for describing purpose, without
It is understood that to indicate or imply relative importance or the implicit quantity for indicating indicated technical characteristic.Of the present utility model
In description, " multiple " are meant that two or more, unless otherwise specifically defined.
In this application, unless otherwise clearly defined and limited, the term such as term " connected ", " connection ", " fixation " should
It is interpreted broadly, for example, it may be fixedly connected or be detachably connected, or integrally；It can be electrical connection；Can be with
It is to be joined directly together, can also be indirectly connected to by intermediary, can is connection or the phase of two elements of two element internals
Interaction relation.For the ordinary skill in the art, above-mentioned term can be understood in this practicality as the case may be
Concrete meaning in new.
In specification of the present utility model, numerous specific details are set forth.It is to be appreciated, however, that reality of the present utility model
Applying example can put into practice in the case of these no details.In some instances, known method is not been shown in detail, is
System and technology, so as not to obscure the understanding of this description.
In the description of this specification, reference term " one embodiment ", " some embodiments ", " example ", " specifically show
The description of example " or " some examples " etc. means to combine specific features, system, material or the spy that the embodiment or example are described
Point is contained at least one embodiment of the present utility model or example.In this manual, to the schematic table of above-mentioned term
State and be necessarily directed to identical embodiment or example.Moreover, specific features, system, material or the feature of description can be with
Combined in an appropriate manner in any one or more embodiments or example.In addition, in the case of not conflicting, this area
Technical staff the not be the same as Example or the feature of example and non-be the same as Example or example described in this specification can be entered
Row is combined and combined.
Finally it should be noted that：Various embodiments above is only limited to illustrate the technical solution of the utility model, rather than to it
System；Although the utility model is described in detail with reference to foregoing embodiments, one of ordinary skill in the art should
Understand：It can still modify to the technical scheme described in foregoing embodiments, or to which part or whole
Technical characteristic carries out equivalent substitution；And these modifications or replacement, the essence of appropriate technical solution is departed from this practicality newly
The scope of each embodiment technical scheme of type, it all should cover among claim of the present utility model and the scope of specification.
Claims (10)
1. a kind of overvoltage crowbar for Switching Power Supply, it is characterised in that including：Sample circuit, logic control circuit, return
Difference circuit；
The input of the sample circuit is connected with power supply；
The output end of the sample circuit is connected with the output end of the logic control circuit；
One end of the return difference circuit is connected on sample circuit, and the other end is connected on logic control circuit；The return difference electricity
Road is used to be controlled the scope of the critical voltage of the overvoltage crowbar, and the logic control circuit is used for controlling switch
Power supply is turned on and off.
2. overvoltage crowbar according to claim 1, it is characterised in that the sample circuit, including：First resistor,
Second resistance and voltage reference chip；
The first end of the first resistor is connected with power supply；
Second end of the first resistor is connected with the first end of the second resistance；
The first end of the second resistance is connected with the reference pole of the voltage reference chip；Second end of the second resistance with
The anode connection of the voltage reference chip, and be grounded；The negative electrode of the voltage reference chip connects with the logic control circuit
Connect；
When the voltage at the second resistance two ends is not less than the reference voltage of the voltage reference chip, the voltage reference core
Piece is turned on；When the voltage at the second resistance two ends is less than the reference voltage of the voltage reference chip, the voltage reference
Chip is not turned on.
3. overvoltage crowbar according to claim 2, it is characterised in that the logic control circuit, including：3rd electricity
Resistance, the 4th resistance, the 5th resistance, the 6th resistance；
The first end of the 3rd resistor is connected with built-in power, and the of the second end of the 3rd resistor and the 4th resistance
One end is connected；
Second end of the 3rd resistor is connected with the negative electrode of the voltage reference chip, the second end of the 4th resistance and institute
The anode connection of voltage reference chip is stated, and is grounded；
The first end of 5th resistance is connected with the built-in power, the second end and the 6th resistance of the 5th resistance
First end connection, the second end of the 6th resistance is connected with the second end of the 4th resistance, and is grounded.
4. overvoltage crowbar according to claim 3, it is characterised in that the logic control circuit, including：First opens
Gateway controller, second switch controller；
The first switch controller uses NPN triode or N-channel MOS pipe；
The second switch controller uses NPN triode or N-channel MOS pipe.
5. overvoltage crowbar according to claim 4, it is characterised in that the first switch controller uses NPN tri-
Pole pipe；
The base stage of the first switch controller is connected with the first end of the 4th resistance；The collection of the first switch controller
Electrode is connected with the second end of the 5th resistance；The emitter stage of the first switch controller and the second of the 4th resistance
End connection, and be grounded；
When the voltage reference chip is turned on, the first switch controller is not turned on；When the voltage reference chip is not led
When logical, the first switch controller conducting.
6. overvoltage crowbar according to claim 4, it is characterised in that the second switch controller uses NPN tri-
Level pipe；
The base stage of the second switch controller is connected with the first end of the 6th resistance；The collection of the second switch controller
Electrode is connected with control chip；The emitter stage of the second switch controller is connected with the second end of the 6th resistance, and is connect
Ground；
When the voltage reference chip is turned on, the first switch controller is not turned on, the second switch controller conducting,
The Switching Power Supply is in guard mode；When the voltage reference chip is not turned on, the first switch controller conducting is described
Second switch controller is not turned on, and the Switching Power Supply is in normal operating conditions.
7. overvoltage crowbar according to claim 3, it is characterised in that the logic control circuit, in addition to：First
Electric capacity；
First electric capacity is connected with the 6th resistor coupled in parallel.
8. overvoltage crowbar according to claim 4, it is characterised in that the return difference circuit, including：7th resistance,
Diode；
7th resistance is connected with the Diode series, and the first end of the positive pole of the diode and the 7th resistance connects
Connect, the second end of the 7th resistance is connected with the first end of the second resistance, the negative pole of the diode and the described 5th
The second end connection of resistance；
When the first switch controller is turned on, the return difference circuit turn-on, the return difference circuit and the second resistance are simultaneously
Connection；When the first switch controller is not turned on, the return difference circuit is not turned on.
9. overvoltage crowbar according to claim 2, it is characterised in that the voltage reference chip is using low-voltage essence
Mi Ketiaocankaoyuan or programmable precision reference source.
10. overvoltage crowbar according to claim 2, it is characterised in that the sample circuit, in addition to：Second electricity
Hold；
Second electric capacity is connected in parallel with the second resistance.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201720076689.5U CN206442106U (en) | 2017-01-19 | 2017-01-19 | A kind of overvoltage crowbar for Switching Power Supply |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201720076689.5U CN206442106U (en) | 2017-01-19 | 2017-01-19 | A kind of overvoltage crowbar for Switching Power Supply |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN206442106U true CN206442106U (en) | 2017-08-25 |
Family
ID=59635491
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201720076689.5U Expired - Fee Related CN206442106U (en) | 2017-01-19 | 2017-01-19 | A kind of overvoltage crowbar for Switching Power Supply |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN206442106U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2019095536A1 (en) * | 2017-11-20 | 2019-05-23 | 深圳光峰科技股份有限公司 | Overvoltage protection circuit and projector |
| CN110768215A (en) * | 2019-10-22 | 2020-02-07 | 广州金升阳科技有限公司 | Output overvoltage protection control circuit of switching power supply and control method thereof |
-
2017
- 2017-01-19 CN CN201720076689.5U patent/CN206442106U/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2019095536A1 (en) * | 2017-11-20 | 2019-05-23 | 深圳光峰科技股份有限公司 | Overvoltage protection circuit and projector |
| CN109818343A (en) * | 2017-11-20 | 2019-05-28 | 深圳光峰科技股份有限公司 | A kind of overvoltage crowbar and projector |
| CN109818343B (en) * | 2017-11-20 | 2021-06-08 | 深圳光峰科技股份有限公司 | Overvoltage protection circuit and projector |
| CN110768215A (en) * | 2019-10-22 | 2020-02-07 | 广州金升阳科技有限公司 | Output overvoltage protection control circuit of switching power supply and control method thereof |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN102762011B (en) | LED (Light Emitting Diode) constant-current dimming drive circuit device | |
| CN106024521A (en) | Coil control circuit of contactor | |
| CN108599123A (en) | The short-circuit protection circuit and television set of power switch | |
| CN105813263A (en) | Switching power supply and television | |
| CN101778513A (en) | LED flow equalizing control circuit, LED driver module and navigation aiding light | |
| CN207069897U (en) | Start-up circuit and inverse-excitation type switch power-supply | |
| CN206442106U (en) | A kind of overvoltage crowbar for Switching Power Supply | |
| CN106034369A (en) | LED power supply with short-circuit protection circuit | |
| CN207150147U (en) | Overvoltage crowbar and switching power supply | |
| CN203445592U (en) | High-side output circuit with short-circuit protection | |
| CN208508899U (en) | A kind of inexpensive IGBT switch controlled circuit of high reliability | |
| CN205210746U (en) | Constant current control ware and constant current control circuit | |
| CN106793346A (en) | Low-voltage dimming power source | |
| CN208971480U (en) | The DC power supply switch circuit that can be rapidly switched off and the electronic equipment using it | |
| CN204681274U (en) | A kind of brshless DC motor metal-oxide-semiconductor drive circuit | |
| CN208861199U (en) | A kind of multilevel decompression voltage regulator circuit with clamper function | |
| CN207251458U (en) | Current over pulse protects circuit and switching power circuit | |
| CN202503439U (en) | Capacitance-resistance voltage reduction circuit of low power supply | |
| CN205987136U (en) | Television board card power supply protection circuit | |
| CN204615621U (en) | The identification circuit of fault-signal | |
| CN204271611U (en) | A kind of alternating current inputting over/under voltage protective circuit | |
| CN204168548U (en) | LED adjusting control circuit | |
| CN208754024U (en) | A kind of switched charge circuit | |
| CN208707519U (en) | Control switch circuit and switching power circuit | |
| CN203691701U (en) | Device for controlling input surge current of LED module |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20170825 Termination date: 20210119 |