CN206533114U - Power supply overvoltage protection circuit and power supply - Google Patents
Power supply overvoltage protection circuit and power supply Download PDFInfo
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- CN206533114U CN206533114U CN201621335445.6U CN201621335445U CN206533114U CN 206533114 U CN206533114 U CN 206533114U CN 201621335445 U CN201621335445 U CN 201621335445U CN 206533114 U CN206533114 U CN 206533114U
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Abstract
The utility model is related to a kind of power supply overvoltage protection circuit and power supply, and the power supply overvoltage protection circuit includes being connected with the output end of power supply, and the sample circuit of sampled voltage is exported based on output voltage；It is connected with sample circuit, the comparison control circuit for being compared and being turned on when sampled voltage exceedes reference voltage to sampled voltage and reference voltage；Reference voltage is the reference voltage inside comparison control circuit；It is connected with comparison control circuit, starts the feedback circuit of simultaneously output feedback signal when comparison control circuit is turned on；It is connected with feedback circuit, based on feedback signal output control signal with the pwm control circuit of power cutoff.The technical program can power supply occur overvoltage when timely power cutoff; effectively protect power supply and power device; it can also improve drift of the power work in extremely low temperature environment or high temperature simultaneously; enhance stability, the security of power supply; slow down load aging fall time, extend the service life of power supply and product.
Description
Technical field
The utility model is related to the technical field of power supply, more specifically to a kind of power supply overvoltage protection circuit and electricity
Source.
Background technology
With the progress and development of science and technology, in LED power technical field, the overpressure problems of driving power supply be always people not
Negligible problem.It is generally only to be solved by common voltage-regulator diode in existing traditional small-signal overvoltage crowbar
The problem of certainly power supply is over-pressed, but conventional circuit design mode lacks while power supply overpressure problems are solved in the presence of certain
Fall into, for example, precision is relatively low, be typically only capable to reach ± 5%, and load capacity is poor, input voltage it is more higher than voltage stabilizing value when
Wait circuit loss greatly, this is disagreed with current low-power consumption requirement, and when power supply own temperature increases, conventional voltage-regulator diode
Voltage stabilizing value be easily influenced by temperature and then the phenomenon drifted about occur.Therefore, a kind of improved overvoltage crowbar need to be proposed.
Utility model content
The technical problems to be solved in the utility model is, for the drawbacks described above of prior art, there is provided a kind of power supply mistake
Voltage protection circuit and power supply.
The utility model solves the technical scheme that its technical problem used：A kind of power supply overvoltage protection circuit is constructed,
Including：
It is connected with the output end of the power supply, the sample circuit of sampled voltage is exported based on the output voltage；
It is connected, the sampled voltage and reference voltage is compared and super in the sampled voltage with the sample circuit
Cross the comparison control circuit turned on during the reference voltage；The reference voltage is the benchmark electricity inside the comparison control circuit
Pressure；
Be connected with the comparison control circuit, when the comparison control circuit is turned on start and output feedback signal it is anti-
Current feed circuit；
It is connected, is controlled based on the feedback signal output control signal with the PWM for turning off the power supply with the feedback circuit
Circuit processed.
In power supply overvoltage protection circuit described in the utility model, it is preferable that also including being connected to the defeated of the power supply
The threshold circuit gone out between end and the comparison control circuit, the threshold circuit is set with threshold voltage, and in the power supply
The voltage that the output voltage of output end branches to the threshold circuit is turned on when reaching the threshold voltage.
In power supply overvoltage protection circuit described in the utility model, it is preferable that the threshold circuit includes the first voltage stabilizing
Diode ZD1；
The negative electrode of the first voltage-regulator diode ZD1 is connected with the output end of the power supply, first voltage-regulator diode
ZD1 anode is connected to the comparison control circuit；
The first voltage-regulator diode ZD1 reaches institute in the voltage that the output end of the power supply branches to the threshold circuit
When stating the first voltage-regulator diode ZD1 voltage stabilizing value, the first voltage-regulator diode ZD1 conductings.
In power supply overvoltage protection circuit described in the utility model, it is preferable that the sample circuit includes the first sampling
Resistance R3, the second sampling resistor R4 and the 3rd sampling resistor R5, first end and the power supply of the first sampling resistor R3
Output end connection, the second end of the first sampling resistor R3 is connected with the first end of the second sampling resistor R4, described
Second sampling resistor R4 the second end is connected with the first end of the 3rd sampling resistor R5, and the of the 3rd sampling resistor R5
Two ends connect the first reference ground；Node between the second sampling resistor R4 and the 3rd sampling resistor R5 is additionally coupled to institute
State comparison control circuit；
The first sampling resistor R3, the second sampling resistor R4 and the 3rd sampling resistor R5 are to the electricity
The output voltage in source carries out sampling output sampled voltage, wherein the sampled voltage is the second sampling resistor R4 and described the
Node voltage between three sampling resistor R5.
In power supply overvoltage protection circuit described in the utility model, it is preferable that the comparison control circuit includes second
Voltage-regulator diode U2, the second voltage-regulator diode U2 include first end, the second end and the 3rd end, wherein,
The first end of the second voltage-regulator diode U2 is refers to pole, and the second end of the second voltage-regulator diode U2 is sun
Pole, the 3rd end of the second voltage-regulator diode U2 is negative electrode；
The negative electrode of the second voltage-regulator diode U2 is connected with the threshold circuit, the sun of the second voltage-regulator diode U2
Pole connects the first reference ground, and the reference pole of the second voltage-regulator diode U2 is connected to the second sampling resistor R4 and described the
Node between three sampling resistor R5；
The reference pole of the second voltage-regulator diode U2 is used to monitor the second sampling resistor R4 and the 3rd sampling
Node voltage between resistance R5, is compared to the node voltage, the reference voltage and exceedes in the node voltage
During the reference voltage, the anode and negative electrode of the second voltage-regulator diode U2, the second voltage-regulator diode U2 conductings are turned on.
In power supply overvoltage protection circuit described in the utility model, it is preferable that the second voltage-regulator diode U2 is three
Hold programmable voltage-regulator diode.
In power supply overvoltage protection circuit described in the utility model, it is preferable that the feedback circuit includes photoelectric coupling
Device U1；The photoelectrical coupler U1 includes first level led U1-A and secondary U1-B level in reception source receives source U1-B；
The just level led U1-A anode is connected with current-limiting resistance R1 the second end, the primary light-emitting diodes
Pipe U1-A negative electrode is connected with the negative electrode of the second voltage-regulator diode U2；
The output end of the secondary reception source U1-B is connected with the pwm control circuit, the secondary reception source U1-B's
Earth terminal connects the second reference ground.
In power supply overvoltage protection circuit described in the utility model, it is preferable that the pwm control circuit includes control core
Piece, the control chip includes signal detection pin and controlling switch, the signal detection pin and the photoelectrical coupler U1
Output end connection, the controlling switch is connected with the input of the power supply；
The control chip receives the feedback of the output end output of the photoelectrical coupler U1 in the signal detection pin
During signal, the input for controlling the controlling switch to output control signals to the power supply turns off the power supply.
In power supply overvoltage protection circuit described in the utility model, it is preferable that also including shunt capacitance C1, the bypass
Electric capacity C1 is in parallel with the 3rd sampling resistor R5, for being filtered to the voltage on the 3rd sampling resistor R5.
The utility model additionally provides a kind of power supply, including above-mentioned overvoltage crowbar.
Implement power supply overvoltage protection circuit of the present utility model and power supply, have the advantages that：It is of the present utility model
Power supply overvoltage protection circuit includes being connected with the output end of the power supply, and the sampling of sampled voltage is exported based on the output voltage
Circuit；It is connected with the sample circuit, the sampled voltage is compared with reference voltage and exceeded in the sampled voltage
The comparison control circuit turned on during the reference voltage；The reference voltage is the benchmark electricity inside the comparison control circuit
Pressure；It is connected with the comparison control circuit, starts when the comparison control circuit is turned on and the feedback of output feedback signal is electric
Road；It is connected with the feedback circuit, electricity is controlled with the PWM for turning off the power supply based on the feedback signal output control signal
Road.The technical program can when there is overvoltage in power supply timely power cutoff, effective protection power supply and power device, while can also change
Kind drift of the power work in extremely low temperature environment or high temperature, enhances stability, the security of power supply, slows down load aging
Fall time, extends the service life of power supply and product.
Brief description of the drawings
Below in conjunction with drawings and Examples, the utility model is described in further detail, in accompanying drawing：
Fig. 1 is the structural representation of the utility model power supply overvoltage protection circuit；
Fig. 2 is the circuit theory diagrams of the utility model power supply overvoltage protection circuit first embodiment.
Embodiment
In order that the purpose of this utility model, technical scheme and advantage are more clearly understood, below in conjunction with accompanying drawing and implementation
Example, the utility model is further elaborated.
The problem of existing for prior art, the utility model proposes a kind of power supply overvoltage protection circuit, the power supply mistake
Voltage protection circuit is exceeded default by setting threshold circuit between power output end and comparison control circuit in output voltage
Be worth, branch to threshold circuit voltage reach threshold circuit setting threshold voltage when, threshold circuit conducting, while sample circuit
The sampled voltage of output have also exceeded the reference voltage in comparison control circuit, and now comparison control circuit is according to the sampled voltage
Turn on and start feedback circuit, by feedback circuit to pwm control circuit output feedback signal, by pwm control circuit according to anti-
The input and then power cutoff of feedback signal control power supply, ensure that power supply timely power cutoff when there is overvoltage, have
Effect protects power supply, it is to avoid power supply damages power supply and power device because of overvoltage work.Improve power supply stability and
Security.
As shown in figure 1, in the structural representation of power supply overvoltage protection circuit of the present utility model, the power supply overvoltage protection
Circuit includes the threshold circuit 100 for being set with threshold voltage；It is connected with the output end of power supply, based on output voltage output sampling electricity
The sample circuit 200 of pressure；It is connected, is led when sampled voltage exceedes reference voltage with threshold circuit 100, sample circuit 200 respectively
Logical comparison control circuit 300；It is connected to lead based on sampled voltage in comparison control circuit 300 with comparison control circuit 300
Start the feedback circuit 400 of simultaneously output feedback signal when logical；It is connected with feedback circuit 400, based on feedback signal output control letter
Number pwm control circuit 500.It is to be appreciated that power supply overvoltage protection circuit of the present utility model can be applied to LED field,
Such as can as LED drive power overvoltage crowbar, load can be LED, can be single lamp, whole lamp or cluster of lamps, ornamental etc..
Preferably, power supply can bear most when the preset value of the electric power output voltage in the present embodiment is Power Management Design
Big value, the maximum can be determined according to the demand of load and the relevant design requirement of circuit, for example, can be 36V, 42V
Deng.It is to be appreciated that the utility model is not limited to listed concrete numerical value to the preset value of electric power output voltage.
Threshold circuit 100 is set with threshold voltage, and it is arranged between power output end and comparison control circuit 300, uses
Protected in comparison control circuit 300.When the voltage that the output voltage of power output end branches to threshold circuit 100 reaches
During threshold voltage, threshold circuit 100 is turned on.It is to be appreciated that the threshold voltage of threshold circuit 100 is by specific threshold circuit
Determine.Preferably, threshold circuit 100 may include voltage-regulator diode, and electric power output voltage is monitored by voltage-regulator diode, when
When the voltage for branching to voltage-regulator diode reaches the voltage stabilizing value of voltage-regulator diode, voltage-regulator diode conducting.In the present embodiment, door
The threshold voltage on road 100 of rationing the power supply can be set to 18V, and when the voltage for branching to voltage-regulator diode reaches 18V, voltage-regulator diode is led
It is logical.It is to be appreciated that in the present embodiment, threshold circuit 100 produces protective effect to comparison control circuit, such as occur in power supply
When over-pressed, due to there is threshold circuit 100 to carry out partial pressure so that flowing to comparison control circuit 300 to Shunt Voltage after switch
Voltage make not over the threshold value of comparison control circuit 300 comparison control circuit 300 can be worked in normal working voltage and
Protection is obtained to be not damaged by.In addition, the circuit that the series connection partial pressure of voltage-regulator diode can make the present embodiment overall is not compared control
The restriction of the maximum operating voltage of circuit 300 processed.
Sample circuit 200 is used to sample to the output voltage of power output end, and exports sampled voltage to comparing control
Circuit 300 processed.It is to be appreciated that the enabling signal that the sampled voltage is turned on as comparison control circuit 300, when the output of power supply
When voltage exceeds preset value, sampled voltage exceedes the reference voltage of comparison control circuit 300, and now comparison control circuit 300 is just
It can turn on.Preferably, sample circuit 200 can be made up of the resistant series of different resistances, and quantity and the resistance of the resistance used
Value can carry out selection determination according to actual circuit.The utility model is not construed as limiting to this.
Comparison control circuit 300 is mainly used in monitoring the sampled voltage that sample circuit 200 is produced, while starting feedback circuit
400, i.e. comparison control circuit 300 pass through the sampled voltage that is exported to sample circuit 200 and the base inside comparison control circuit 300
Quasi- voltage is compared, and is controlled according to comparative result, is turned on when monitoring that sampled voltage exceedes reference voltage, feedback electricity
Road 400 starts when comparison control circuit 300 is turned on, and feedback letter is exported by feedback circuit 400 after the startup of feedback circuit 400
Number.It is to be appreciated that comparison control circuit 300 branches to thresholding in output voltage beyond the output voltage of preset value and power supply
When the voltage of circuit 100 reaches threshold voltage, the sampled voltage that comparison control circuit 300 is exported according to sample circuit exceedes benchmark
Turned on during voltage.Specifically, when the output voltage of power output end exceeds preset value, for example, the preset value of output voltage is
42V, threshold voltage is 18V, i.e., when output voltage is more than 42V, it is assumed that in the circuit design of the present embodiment, now branch to
The threshold voltage of threshold circuit 100 reaches 18V, then threshold circuit 100 is turned on, and the voltage signal of shunting flows through threshold circuit
100；Meanwhile, comparison control circuit 300 monitors that the sampled voltage that sample circuit 200 is exported exceedes comparison control circuit 300
Reference voltage, now due to the characteristic of itself of comparison control circuit 300, when the reference of comparison control circuit 300 is extremely received
Magnitude of voltage be more than with reference to pole reference voltage when, comparison control circuit 300 is turned on.In the present embodiment, comparison control circuit
300 preferably have the programmable voltage-regulator diode in three ends, and its model can select TL431B.TL431B can be set to reference to the voltage of pole
2.5V~36V, preferably 2.5V.If be set to 2.5V with reference to the reference voltage of pole, when the magnitude of voltage of sampled voltage is more than 2.5V,
Comparison control circuit 300 is turned on.
In the present embodiment, comparison control circuit 300 selects the model TL431B programmable voltage-regulator diode in three ends,
TL431B includes negative electrode, anode and refers to the electrode of pole three, and 2.5V~36V can be arbitrarily set to by being typically referenced to the reference voltage of pole.
The Voltage Reference error of the voltage-regulator diode is ± 0.4V, and dynamic output impedance only has 0.22 ohm.Using the pole of voltage stabilizing two
Pipe can realize that temperature characterisitic is flat in the range of fully fixed operating temperature range, total temperature, i.e., when higher temperature occurs in power supply
When, drift phenomenon will not be produced because of the influence of temperature, and when low temperature environment works due to TL431B characteristic (low temperature ring
Border service behaviour is unaffected), therefore can be applied to extremely low working environment.Therefore, power supply of the present utility model from this three
Hold programmable voltage-regulator diode power supply is worked in extremely low temperature environment and drift phenomenon will not be produced, improve electricity
The stability and precision in source.In addition, the programmable voltage-regulator diode in three ends is cheap, the material of power supply reduce further
Cost.
It is to be appreciated that when power supply is in normal range of operation, threshold circuit 100 and comparison control circuit 300 are not
Conducting, the work on power supply does not produce influence.
Feedback circuit 400, for being activated when comparison control circuit 300 is turned on, while upon actuation to PWM controls
The output feedback signal of circuit 500.For example, when power supply is in normal range of operation, comparison control circuit 300 is not turned on, that is, is compared
Relatively control circuit 300 is off, and now due to the effect of comparison control circuit 300, feedback circuit 400 does not work.When
When electric power output voltage exceeds preset value, i.e., there is the situation of overvoltage in power supply, now the reference pole monitoring of comparison control circuit 300
Detect that overvoltage occurs in power supply more than reference voltage, i.e. comparison control circuit 300 to sampled voltage, by comparison control circuit 300
Characteristic, when the sampled voltage received be more than with reference to pole reference voltage when, comparison control circuit 300 is turned on, so turn on
Feedback circuit 400, i.e., feedback circuit 400 is activated, and output feedback signal.It is to be appreciated that the feedback signal is used for instead
Answer the overpressure situation of power supply.
Preferably, feedback circuit 400 may include photoelectrical coupler.Photoelectrical coupler is because of its unique design feature, therefore
Having in actual use makes signal scene with main control end electrically completely isolated, can be in different potentials and different impedances
Between transmitting telecommunication number, switching speed is fast, small volume, the characteristics of easy to use, therefore, in the present embodiment, from photoelectricity coupling
Clutch is the work for not interfering with load as feedback circuit, rapidly can also be fed back to signal when overvoltage occurs in power supply
Control circuit reacts the state of power supply in time.
Pwm control circuit 500 is used to control the input of power supply according to feedback signal output control signal with power supply mistake
Timely power cutoff during pressure.
As shown in Fig. 2 in the schematic diagram of the circuit theory diagrams of power supply overvoltage protection circuit：
Threshold circuit 100 includes the first voltage-regulator diode ZD1.The output of first voltage-regulator diode ZD1 negative electrode and power supply
End connection, the first voltage-regulator diode ZD1 anode is with being connected to comparison control circuit 300.As shown in Fig. 2 power supply overvoltage is protected
Protection circuit also including current-limiting resistance R1 and biasing resistor R2, current-limiting resistance R1 and biasing resistor R2 be connected on thresholding resistance 100 with
Between comparison control circuit 300.When the output voltage of power output end branches to the threshold voltage of threshold circuit 100, thresholding
Circuit 100 is turned on, and the voltage of shunting flow to biasing resistor R2 after carrying out current limliting through current-limiting resistance R1, through biasing resistor R2 to comparing
Circuit 300 is controlled to provide stable static working current.It is to be appreciated that in the present embodiment, current-limiting resistance R1 and biased electrical
Hinder R2 and protective effect further is provided to comparison control circuit 300, to avoid when thresholding resistance 100 is turned on to comparing control
Circuit 300 produces overshoot effect and damage comparison controls circuit 300.
Sample circuit 200 includes the first sampling resistor R3, the second sampling resistor R4 and the 3rd sampling resistor R5.First adopts
Sample resistance R3 first end and the output end of power supply are connected, and the of the first sampling resistor R3 the second end and the second sampling resistor R4
One end is connected；Second sampling resistor R4 the second end is connected with the 3rd sampling resistor R5 first end, the 3rd sampling resistor R5's
Second end connects the first reference ground.It is to be appreciated that sample circuit 200 carries out partial pressure to the output voltage of power supply and produces sampling
Voltage, the sampled voltage is the node voltage between the second sampling resistor R4 and the 3rd sampling resistor R5.Preferably, sampling electricity
Pressure is sent to the reference pole of comparison control circuit 300, and by the reference of comparison control circuit 300, extremely to sampled voltage, (i.e. second adopts
Node voltage between sample resistance R4 and the 3rd sampling resistor R5) it is monitored.
Comparison control circuit 300, which includes the second voltage-regulator diode U2, the second voltage-regulator diode U2, includes first end, the second end
And the 3rd end, wherein, the second voltage-regulator diode U2 first end is to refer to pole R, and the second voltage-regulator diode U2 the second end is
Anode A, the second voltage-regulator diode U2 the 3rd end is negative electrode K.Second voltage-regulator diode U2 negative electrode K's and biasing resistor R2
Second end connects (being connected by biasing resistor with thresholding resistance 100), and the second voltage-regulator diode U2 anode A connection first is joined
Ground is examined, the second voltage-regulator diode U2 reference pole R is connected to the section between the second sampling resistor R4 and the 3rd sampling resistor R5
Point.It is to be appreciated that the second voltage-regulator diode U2 reference pole R2 receives the sampled voltage (i.e. second that sample circuit 200 is exported
Node voltage between sampling resistor R4 and the 3rd sampling resistor R5), monitor whether it exceedes with reference to pole R based on the node voltage
Reference voltage, when monitor node voltage exceed with reference to pole R reference voltage when, the second voltage-regulator diode U2 conducting, and then
Start feedback circuit 400.In the present embodiment, the programmable voltage-regulator diode in the second voltage-regulator diode U2 preferably three ends, model
Three ends that can select TL431B may be programmed voltage-regulator diode.TL431B with reference to pole reference voltage can arbitrarily be set to 2.5V~
36V.TL431B voltage-regulator diodes refer to the pole R preferred 2.5V of reference voltage in the present embodiment.
Feedback circuit 400 includes photoelectrical coupler U1.As shown in Fig. 2 photoelectrical coupler U1 is including just level led
U1-A and time reception source U1-B.First level led U1-A anode is connected with current-limiting resistance R1 the second end, and primary is luminous
Diode U1-A negative electrode is connected with the second voltage-regulator diode U2 negative electrode K.Secondary reception source U1-B output end is controlled with PWM
Circuit 500 processed is connected, and secondary reception source U1-B earth terminal connects the second reference ground.It is to be appreciated that feedback circuit 400 is
When two voltage-regulator diode U2 are turned on, first level led U1-A is switched on and lighted, then secondary reception source U1-B receives source and existed
First level led U1-A is turned on when lighting according to the intensity of light source, and output end LATCH output feedback signals to PWM control electricity
Road 500.Preferably, in the present embodiment, the feedback signal is low level signal.
Pwm control circuit 500 is (not specifically shown in fig. 2) to include control chip (not shown).Control chip includes letter
Number detection pin and controlling switch, signal detection pin be connected with photoelectrical coupler U1 output end LATCH, controlling switch and electric
The input connection in source.It is to be appreciated that control chip receives photoelectrical coupler U1 output end in signal detection pin
After the low level feedback signal of LATCH outputs, controlling switch is controlled to output control signals to electricity according to the low level feedback signal
The input in source, and then power cutoff, realize and power supply are rapidly closed in time when power supply is over-pressed, power supply is stopped,
It is effectively protected power supply and load.
Further, in the present embodiment, power supply overvoltage protection circuit also include shunt capacitance C1, shunt capacitance C1 with
3rd sampling resistor R5 is in parallel, for being filtered to the voltage on the 3rd sampling resistor R5.It is to be appreciated that in the 3rd sampling
Shunt capacitance C1 in parallel, the interference component on the 3rd sampling resistor R5 can be filtered out in time, pre- false action-proof is kept away on resistance R5
Exempt from the monitoring mistake that the second voltage-regulator diode U2 refers to pole R.
The concrete operating principle of overvoltage crowbar is illustrated below according to Fig. 2.
For example, in the present embodiment, the maximum of electric power output voltage is 42V, according to the design requirement of circuit, to make electricity
Pressure flow to the range of safety operation of comparison control circuit 300, and the threshold voltage for taking threshold circuit 100 is 18V, comparison control circuit
300 select the programmable voltage-regulator diode in the ends of TL431B tri-, and it is set to 2.5V with reference to pole R reference voltage.
It is to be appreciated that when electric power output voltage is when less than 42V, i.e. power supply normal work, protection circuit no current leads to
Cross the work on power supply and do not produce influence；When the output voltage of power supply is more than 42V, protection circuit is activated produces guarantor to power supply
Shield is acted on.Specifically：
When the output voltage of power supply is more than 42V, i.e. power supply overvoltage, electric power output voltage branches to the first voltage-regulator diode U1
On voltage reach the first voltage-regulator diode U1 voltage stabilizing value 18V, the first voltage-regulator diode U1 conductings, while through the first sampling electricity
Hinder R3, the second sampling resistor R4 and the 3rd sampling resistor R5 sampling produced by sampled voltage, i.e. the second sampling resistor R4 with
Node voltage between 3rd sampling resistor R5 is more than 2.5V, and now, the second voltage-regulator diode U2 reference pole R monitors second
Node voltage (sampled voltage) between sampling resistor R4 and the 3rd sampling resistor R5 is more than 2.5V, the second voltage-regulator diode U2's
Negative electrode K is turned on anode A, i.e. the second voltage-regulator diode U2 is switched on, and the electric current through the first voltage-regulator diode U1 passes through current limliting electricity
Resistance R1 flows through photoelectrical coupler U1 first level led U1-A, and is connected to the first ginseng by the second voltage-regulator diode U2
Examine ground.When photoelectrical coupler U1 first level led U1-A is switched on, just level led U1-A produces light source, light
Electric coupler U1 secondary reception source U1-B is turned on according to the first level led U1-A intensity of light source, by output end (i.e.
LATCH pin) level drag down, i.e., control chip of signal detection pin from the LATCH pin to pwm control circuit 500 send one
Individual low level feedback signal, makes the feedback signal that control chip is detected according to signal detection pin output control signals to electricity
The input and then power cutoff in source, make power supply be stopped, so as to quickly close power supply, realize the mistake to power supply
Pressure protection.
Further, above-mentioned simply preferred embodiment of the present utility model, when the power supply or occasion that are used in other models
When needing different output voltages, different voltage-regulator diodes are can select, and change the first sampling resistor R3, the second sampling resistor
The resistance ratio of R4 and the 3rd sampling resistor R5 resistance value and three, makes sample circuit 200 reach the numerical value of needs, meets
The design requirement of circuit.
It is to be appreciated that the utility model adds overvoltage crowbar by the output end in power supply, that is, add TL431B
The programmable voltage-regulator diode in three ends, improve the monitoring accuracy to electric power output voltage, power work can be effectively improved and existed
Extremely low temperature environment, while avoiding power supply is in drift phenomenon produced during higher temperature, while there is overvoltage in power supply
When timely power cutoff, power supply is stopped power supply in time, enhance stability, the reliability and safety of power supply, and slow down
The time of load such as LED lamp bead degradation, extend the service life of power supply and product.
The utility model additionally provides a kind of power supply, and the power supply includes aforementioned power source overvoltage crowbar, should by application
Power supply overvoltage protection circuit can improve the stability, security and reliability of power supply, extend the life-span of power supply.
Above example is only to illustrate technical concepts and features of the present utility model, and its object is to allow be familiar with technique
Personage can understand content of the present utility model and implement accordingly, protection domain of the present utility model can not be limited.It is all with
The equivalent changes and modifications that the utility model right is done, all should belong to the utility model claim covers model
Enclose.
It should be appreciated that for those of ordinary skills, can according to the above description be improved or converted,
And all these modifications and variations should all belong to the protection domain of the utility model appended claims.
Claims (10)
1. a kind of power supply overvoltage protection circuit, it is characterised in that including：
It is connected with the output end of the power supply, the sample circuit of sampled voltage is exported based on the output voltage；
It is connected with the sample circuit, the sampled voltage and reference voltage is compared and exceed institute in the sampled voltage
State the comparison control circuit turned on during reference voltage；The reference voltage is the reference voltage inside the comparison control circuit；
It is connected with the comparison control circuit, starts when the comparison control circuit is turned on and the feedback of output feedback signal is electric
Road；
It is connected with the feedback circuit, electricity is controlled with the PWM for turning off the power supply based on the feedback signal output control signal
Road.
2. power supply overvoltage protection circuit according to claim 1, it is characterised in that also including being connected to the defeated of the power supply
The threshold circuit gone out between end and the comparison control circuit, the threshold circuit is set with threshold voltage, and in the power supply
The voltage that the output voltage of output end branches to the threshold circuit is turned on when reaching the threshold voltage.
3. power supply overvoltage protection circuit according to claim 2, it is characterised in that the threshold circuit includes the first voltage stabilizing
Diode ZD1；
The negative electrode of the first voltage-regulator diode ZD1 is connected with the output end of the power supply, the first voltage-regulator diode ZD1's
Anode is connected to the comparison control circuit；
The first voltage-regulator diode ZD1 reaches described in the voltage that the output end of the power supply branches to the threshold circuit
During one voltage-regulator diode ZD1 voltage stabilizing value, the first voltage-regulator diode ZD1 conductings.
4. power supply overvoltage protection circuit according to claim 2, it is characterised in that the sample circuit includes the first sampling
Resistance R3, the second sampling resistor R4 and the 3rd sampling resistor R5, first end and the power supply of the first sampling resistor R3
Output end connection, the second end of the first sampling resistor R3 is connected with the first end of the second sampling resistor R4, described
Second sampling resistor R4 the second end is connected with the first end of the 3rd sampling resistor R5, and the of the 3rd sampling resistor R5
Two ends connect the first reference ground；Node between the second sampling resistor R4 and the 3rd sampling resistor R5 is additionally coupled to institute
State comparison control circuit；
The first sampling resistor R3, the second sampling resistor R4 and the 3rd sampling resistor R5 are to the defeated of the power supply
Go out voltage and carry out sampling output sampled voltage, wherein the sampled voltage is the second sampling resistor R4 and the described 3rd sampling
Node voltage between resistance R5.
5. power supply overvoltage protection circuit according to claim 4, it is characterised in that the comparison control circuit includes second
Voltage-regulator diode U2, the second voltage-regulator diode U2 include first end, the second end and the 3rd end, wherein,
The first end of the second voltage-regulator diode U2 is refers to pole, and the second end of the second voltage-regulator diode U2 is anode,
The 3rd end of the second voltage-regulator diode U2 is negative electrode；
The negative electrode of the second voltage-regulator diode U2 is connected with the threshold circuit, and the anode of the second voltage-regulator diode U2 connects
The first reference ground is connect, the reference pole of the second voltage-regulator diode U2 is connected to the second sampling resistor R4 and adopted with the described 3rd
Node between sample resistance R5；
The reference pole of the second voltage-regulator diode U2 is used to monitor the second sampling resistor R4 and the 3rd sampling resistor
Node voltage between R5, is compared to the node voltage, the reference voltage and exceedes in the node voltage described
During reference voltage, the anode and negative electrode of the second voltage-regulator diode U2, the second voltage-regulator diode U2 conductings are turned on.
6. power supply overvoltage protection circuit according to claim 5, it is characterised in that the second voltage-regulator diode U2 is three
Hold programmable voltage-regulator diode.
7. power supply overvoltage protection circuit according to claim 6, it is characterised in that the feedback circuit includes photoelectric coupling
Device U1；The photoelectrical coupler U1 includes first level led U1-A and secondary U1-B level in reception source receives source U1-B；
The just level led U1-A anode is connected with current-limiting resistance R1 the second end, described just level led
U1-A negative electrode is connected with the negative electrode of the second voltage-regulator diode U2；
The output end of the secondary reception source U1-B is connected with the pwm control circuit, the ground connection of the secondary reception source U1-B
The second reference ground of end connection.
8. power supply overvoltage protection circuit according to claim 7, it is characterised in that the pwm control circuit includes control
Chip, the control chip includes signal detection pin and controlling switch, the signal detection pin and the photoelectrical coupler
U1 output end connection, the controlling switch is connected with the input of the power supply；
The control chip receives the feedback signal of the output end output of the photoelectrical coupler U1 in the signal detection pin
When, the input for controlling the controlling switch to output control signals to the power supply turns off the power supply.
9. power supply overvoltage protection circuit according to claim 4, it is characterised in that also including shunt capacitance C1, the side
Road electric capacity C1 is in parallel with the 3rd sampling resistor R5, for being filtered to the voltage on the 3rd sampling resistor R5.
10. a kind of power supply, it is characterised in that including the overvoltage crowbar as described in any one of claim 1 to 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201621335445.6U CN206533114U (en) | 2016-12-07 | 2016-12-07 | Power supply overvoltage protection circuit and power supply |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201621335445.6U CN206533114U (en) | 2016-12-07 | 2016-12-07 | Power supply overvoltage protection circuit and power supply |
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| Publication Number | Publication Date |
|---|---|
| CN206533114U true CN206533114U (en) | 2017-09-29 |
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ID=59921729
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201621335445.6U Active CN206533114U (en) | 2016-12-07 | 2016-12-07 | Power supply overvoltage protection circuit and power supply |
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| Country | Link |
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| CN (1) | CN206533114U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110719022A (en) * | 2019-10-21 | 2020-01-21 | 珠海格力电器股份有限公司 | Sampling feedback circuit, sampling feedback method and inverter system |
| CN113708617A (en) * | 2021-08-20 | 2021-11-26 | 北京计算机技术及应用研究所 | High-power-density DC/DC power module integrated with EMI filtering |
-
2016
- 2016-12-07 CN CN201621335445.6U patent/CN206533114U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110719022A (en) * | 2019-10-21 | 2020-01-21 | 珠海格力电器股份有限公司 | Sampling feedback circuit, sampling feedback method and inverter system |
| CN113708617A (en) * | 2021-08-20 | 2021-11-26 | 北京计算机技术及应用研究所 | High-power-density DC/DC power module integrated with EMI filtering |
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