CN109088535A - A kind of Switching Power Supply and its soft starting circuit - Google Patents
A kind of Switching Power Supply and its soft starting circuit Download PDFInfo
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- CN109088535A CN109088535A CN201710448304.8A CN201710448304A CN109088535A CN 109088535 A CN109088535 A CN 109088535A CN 201710448304 A CN201710448304 A CN 201710448304A CN 109088535 A CN109088535 A CN 109088535A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/36—Means for starting or stopping converters
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Abstract
The application provides a kind of Switching Power Supply and its soft starting circuit, it is exported by control unit to the control signal of on-off switch control terminal, it is held off on-off switch within the initial stage after Switching Power Supply powers on, due to the limitation of the first resistor and second resistance of big resistance value so that the charging current of filter capacitor keep to a very small extent, charging voltage slowly increases；And on-off switch is controlled to preset regular turn-on and turn-off, filter capacitor is made to charge under preset pressure by phased manner within the adjusting stage, to guarantee that each charging current all very little, charging voltage are presented the step in period one by one and climb；It is tended to remain on after finally voltage of the control on-off switch on filter capacitor meets preset condition, after being connected in locked stage, big charging current and charging voltage step will not occur in filter capacitor before so that rear class converter is entered normal operating conditions；Effectively reduce the power-on surge current and booting surge voltage of Switching Power Supply.
Description
Technical field
The present invention relates to switch power technology field more particularly to a kind of Switching Power Supply and its soft starting circuits.
Background technique
Switching Power Supply has been widely used due to high conversion efficiency, high power density in various power supply occasions.Due to
The power conversion component of rear class converter works in high frequency in Switching Power Supply, therefore is usually arranged in the input terminal of rear class converter
One filter capacitor C improves external electromagnetic interference to filter out high-frequency noise；Fig. 1 show the structure of common Switching Power Supply
Schematic diagram.
Referring to Fig. 1, in switch K0 closure, the booting moment of electric main AC access, it will generate a charging current
Ich charges to filter capacitor C through filter inductance L, rectifier bridge；Since the resistive impedance of this charge circuit is very small, and
The phase of electric main AC be it is random, be possible to be in the AC voltage peaks close to 90 degree in booting moment, therefore lead
It causes the peak value of charging current Ich may be larger, such as reaches several amperes or ten amperes or more, become the booting surge electricity of Switching Power Supply
Stream generates biggish current stress to Switching Power Supply input terminal device, in some instances it may even be possible to lead to the damage of these devices.In addition,
When the power-on surge current flows through filter inductance L, filter inductance L will generate energy storage, the electric current that this energy storage generates when discharging
Also rectifier bridge can be flowed through and charged to filter capacitor C.In the case, the voltage amplitude on filter capacitor C is shown as significantly
The peak value of underdamping overshoot response, the voltage is sometime up to 700V, becomes the booting surge voltage of Switching Power Supply.Due to the filtering
The operating voltage of voltage namely rear class converter on capacitor C, and the excessively high device being easy to cause in rear class converter of operating voltage
Part bears excessively high voltage stress and occurs permanently to damage.Fig. 2 show Switching Power Supply and shows in the waveform that the t0 moment is switched on.
In order to avoid biggish power-on surge current and booting surge voltage damage device, referring to Fig. 3, the prior art is being schemed
On the basis of 1, the thermistor NTC an of negative temperature coefficient is sealed in Switching Power Supply input terminal.When switch K0 closure moment, lead to
The amplitude for crossing the charging current of the resistance value limitation filter capacitor C of thermistor NTC, to reduce booting wave to a certain extent
Gush the amplitude of electric current.But due to the limitation of thermistor NTC material therefor resistivity, and consider thermistor NTC
Operating power consumption, thermistor NTC resistance value generally selects range and is only 10 to 20 ohm, this resistance value is not enough to be substantially reduced
The amplitude of surge current, and then also it is not enough to be substantially reduced the amplitude of the booting surge voltage on rectifier bridge post filtering capacitor.
Summary of the invention
In view of this, can not have the present invention provides a kind of Switching Power Supply and its soft starting circuit to solve the prior art
Effect reduces the problem of power-on surge current and booting surge voltage.
To achieve the goals above, technical solution provided in an embodiment of the present invention is as follows:
A kind of soft starting circuit of Switching Power Supply is connected to the filter capacitor of Switching Power Supply and with reference between ground；It is described to open
The soft starting circuit in powered-down source includes: control unit, on-off switch, first resistor, second resistance and 3rd resistor；Wherein:
The first resistor and the second resistance are connected in series between the filter capacitor and reference ground, concatenated company
Contact is connected with the first input end of described control unit；
The on-off switch and the 3rd resistor are connected in series in the filter capacitor and with reference between ground；
The second resistance with reference is connected with the 3rd resistor；
The sum of resistance value of the first resistor and the second resistance is more than or equal to 100 kilohms；
Described control unit is used to generate control signal according to the received voltage sampling signal of first input end and export extremely
The control terminal of the on-off switch, to make the on-off switch keep closing in the initial stage after the Switching Power Supply powers on
Disconnected state controls the on-off switch within the adjusting stage after the Switching Power Supply powers on default rule conducting and pass
Break, the filter capacitor is made to charge under preset pressure by phased manner, and controls the on-off switch in the filtered electrical
Voltage in appearance meet preset condition after, the Switching Power Supply power on after locked stage in be held on shape after conducting
State.
Preferably, the initial stage, the adjusting stage and the locked stage are with the progress of corresponding preset duration
It divides；
Alternatively, the amplitude that the preset condition is the voltage sampling signal is less than predetermined amplitude.
Preferably, the ratio between resistance value of the first resistor and the second resistance is less than default ratio.
Preferably, the default rule are as follows: when the voltage sampling signal drops to reference voltage reference signal, control
The on-off switch conducting；And after default conducting duration, the on-off switch shutdown is controlled.
Preferably, the second input of the on-off switch and the concatenated tie point of the 3rd resistor and described control unit
End is connected；
The control signal is that described control unit is inputted according to the received voltage sampling signal of first input end and second
It holds received current sampling signal and generates；
The default rule are as follows: when the voltage sampling signal drops to reference voltage reference signal, control described logical
Disconnected switch conduction；And in the current sampling signal zero passage, the on-off switch shutdown is controlled；
Alternatively, the default rule are as follows: when the voltage sampling signal drops to reference voltage reference signal, control institute
State on-off switch conducting；And after default conducting duration or when the current sampling signal zero passage, controls the on-off and open
Shutdown.
Preferably, described control unit includes: the first hysteresis comparator, the first starting timer, the first monostable timing
Device, the first d type flip flop and first or door；Wherein:
The non-inverting input terminal of first hysteresis comparator receives the voltage sampling signal；
The inverting input terminal of first hysteresis comparator receives the reference voltage reference signal；
The output end of first hysteresis comparator is connected with the input terminal of the first monostable timing device；
The output end of the first starting timer is connected with the data terminal of first d type flip flop；
The rising edge triggering end and described first of the output end of the first monostable timing device and first d type flip flop
Or an input terminal of door is connected；
The output end of first d type flip flop is connected with another input terminal of described first or door；
Described first or the output end of door export the control signal.
Preferably, the default rule are as follows: when the voltage sampling signal drops to reference voltage reference signal, control
The on-off switch conducting；And in the current sampling signal zero passage, when controlling on-off switch shutdown, the control is single
Member include: the second hysteresis comparator, the first zero-crossing comparator, second starting timer, edge triggered flip flop, the second d type flip flop and
Second or door；Wherein:
The non-inverting input terminal of second hysteresis comparator receives the voltage sampling signal；
The inverting input terminal of second hysteresis comparator receives the reference voltage reference signal；
The output end of second hysteresis comparator is connected with the set end of the edge triggered flip flop；
The input terminal of first zero-crossing comparator receives the current sampling signal；
The output end of first zero-crossing comparator is connected with the reset terminal of the edge triggered flip flop；
The output end of the second starting timer is connected with the data terminal of second d type flip flop；
The rising edge triggering end of the output end of the edge triggered flip flop and second d type flip flop and one described or door
Input terminal is connected；
The output end of second d type flip flop is connected with another input terminal of described second or door；
Described second or the output end of door export the control signal；
The default rule are as follows: when the voltage sampling signal drops to reference voltage reference signal, control described logical
Disconnected switch conduction；And after default conducting duration or when the current sampling signal zero passage, controls the on-off switch and close
When disconnected, described control unit includes: third hysteresis comparator, the second zero-crossing comparator, third starting timer, the second monostable
Timer, third d type flip flop, third or door and the 4th or door；Wherein:
The non-inverting input terminal of the third hysteresis comparator receives the voltage sampling signal；
The inverting input terminal of the third hysteresis comparator receives the reference voltage reference signal；
The output end of the third hysteresis comparator is connected with the input terminal of the second monostable timing device；
The output end of the second monostable timing device is connected with an input terminal of the third or door；
The input terminal of second zero-crossing comparator receives the current sampling signal；
The output end of second zero-crossing comparator is connected with another input terminal of the third or door；
The output end of the third starting timer is connected with the data terminal of the third d type flip flop；
The rising edge triggering end of the output end of the third or door and the third d type flip flop and the described 4th or door one
A input terminal is connected；
The output end of the third d type flip flop is connected with another input terminal of the described 4th or door；
Described 4th or the output end of door export the control signal.
Preferably, described control unit are as follows: single-chip microcontroller or programmable logic controller PLC.
Preferably, described control unit is set to ic core on piece or described control unit and opens with the on-off
Pass is all set in ic core on piece.
A kind of Switching Power Supply, comprising: filter inductance, urban electric power switch, rectifier bridge, filter capacitor, rear class converter and above-mentioned
The soft starting circuit of any Switching Power Supply；Wherein:
Electric main passes through the two input terminal phases of the filter inductance and the urban electric power switch with the rectifier bridge respectively
Even；
The output head anode of the rectifier bridge passes sequentially through the soft starting circuit of the filter capacitor and the Switching Power Supply,
It is connected with the negative pole of output end of the rectifier bridge and reference；
The rear class converter is in parallel with the filter capacitor.
The application provides a kind of soft starting circuit of Switching Power Supply, is exported by control unit to on-off switch control terminal
Control signal, be held off on-off switch within the initial stage after Switching Power Supply powers on, at this time by with filtering
The limitation of the first resistor and second resistance of the concatenated big resistance value of capacitor, so that the charging current of filter capacitor is maintained at very little
Range is interior, charging voltage slowly increases；And on-off switch is controlled within the adjusting stage after Switching Power Supply powers on default rule
Rule turn-on and turn-off, so that filter capacitor is charged under preset pressure by phased manner, with guarantee each charging current all very little,
The step that the period one by one is presented in charging voltage climbs；Finally voltage of the control on-off switch on filter capacitor meets preset condition
Later, it is tended to remain on after conducting in the locked stage after Switching Power Supply powers on, rear class converter is made to enter normal work
Big charging current and charging voltage step will not occur in filter capacitor before making state.This circuit passes through the control unit
Control, so that in the above-mentioned stage of Switching Power Supply after power-up, charging current on filter capacitor is smaller, charging voltage energy
It is enough stepped up, effectively reduces the power-on surge current and booting surge voltage of Switching Power Supply.
Detailed description of the invention
In order to more clearly explain the embodiment of the invention or the technical proposal in the existing technology, to embodiment or will show below
There is attached drawing needed in technical description to be briefly described, it should be apparent that, the accompanying drawings in the following description is only this
The embodiment of invention for those of ordinary skill in the art without creative efforts, can also basis
The attached drawing of offer obtains other attached drawings.
Fig. 1 is a kind of structural schematic diagram for Switching Power Supply that the prior art provides；
Fig. 2 is the waveform diagram when Switching Power Supply that the prior art provides is switched on；
Fig. 3 is the structural schematic diagram for the Switching Power Supply that the prior art provides；
Fig. 4 is the structural schematic diagram for the Switching Power Supply that the prior art provides；
Fig. 5 is the structural schematic diagram of Switching Power Supply provided by the embodiments of the present application；
Fig. 6 is the structural schematic diagram for the Switching Power Supply that another embodiment of the application provides；
Fig. 7 is the waveform diagram of initial stage after the Switching Power Supply that another embodiment of the application provides powers on；
Fig. 8 is the waveform diagram that the stage is adjusted after the Switching Power Supply that another embodiment of the application provides powers on；
Fig. 9 is the waveform diagram for entering locked stage after the Switching Power Supply that another embodiment of the application provides powers on；
Figure 10 is the structural schematic diagram for the control unit that another embodiment of the application provides；
Figure 11 is the waveform diagram that the stage is adjusted after the Switching Power Supply that another embodiment of the application provides powers on；
Figure 12 is the structural schematic diagram for the control unit that another embodiment of the application provides；
Figure 13 is the structural schematic diagram for the control unit that another embodiment of the application provides.
Specific embodiment
Following will be combined with the drawings in the embodiments of the present invention, and technical solution in the embodiment of the present invention carries out clear, complete
Site preparation description, it is clear that described embodiments are only a part of the embodiments of the present invention, instead of all the embodiments.It is based on
Embodiment in the present invention, it is obtained by those of ordinary skill in the art without making creative efforts every other
Embodiment shall fall within the protection scope of the present invention.
The present invention provides a kind of soft starting circuits of Switching Power Supply, can not effectively reduce booting wave to solve the prior art
The problem of gushing electric current and booting surge voltage.
Specifically, the soft starting circuit of the Switching Power Supply is connected to filter capacitor C and the reference of Switching Power Supply referring to Fig. 5
Between ground；The soft starting circuit of Switching Power Supply includes: control unit, on-off switch K1, first as shown in the dotted line frame in Fig. 5
Resistance R1, second resistance R2 and 3rd resistor R3；Wherein:
First resistor R1 and second resistance R2 is connected in series in filter capacitor C and with reference between ground, concatenated tie point with
The first input end of control unit is connected；
On-off switch K1 and 3rd resistor R3 is connected in series in filter capacitor C and with reference between ground；
Second resistance R2 with reference is connected with 3rd resistor R3；
The sum of resistance value of first resistor R1 and second resistance R2 is more than or equal to 100 kilohms；Preferably, first resistor R1 with
The sum of resistance value of second resistance R2 can take hundred kilohms of grades or megohm grade；It is not specifically limited, is specifically answered depending on it herein
Depending on environment, within the scope of protection of this application.
Control unit is used to generate control signal according to the received voltage sampling signal VS1 of first input end and export extremely
The control terminal of on-off switch K1, be held off on-off switch K1 in the initial stage after Switching Power Supply powers on,
On-off switch K1 is controlled within the adjusting stage after Switching Power Supply powers on to preset regular turn-on and turn-off, make filter capacitor C
It charges under preset pressure by phased manner, and controls voltage of the on-off switch K1 on filter capacitor C and meet preset condition
Later, it is tended to remain on after conducting in the locked stage after Switching Power Supply powers on.
On-off switch K1 can be field-effect tube or bipolar junction transistor or insulated-gate type field effect transistor, or controllable
The switching-type devices such as silicon device, are not specifically limited herein, depending on its specific application environment, in the protection scope of the application
It is interior.
Specific working principle are as follows:
It is exported by control unit to the control signal of on-off switch K1 control terminal, makes on-off switch K1 in Switching Power Supply
Be held off in initial stage after electricity, at this time by first resistor R1 with the concatenated big resistance value of filter capacitor C and
The limitation of second resistance R2 so that the charging current of filter capacitor C keep to a very small extent, charging voltage slowly increases；
And on-off switch K1 is controlled within the adjusting stage after Switching Power Supply powers on to preset regular turn-on and turn-off, make filter capacitor
C charges under preset pressure by phased manner, to guarantee that the period one by one is presented in each charging current all very little, charging voltage
Step climbs；Finally control on-off switch K1 is held on shape after being connected in the locked stage after Switching Power Supply powers on
State, big charging current and charging voltage will not occur in filter capacitor C before so that rear class converter is entered normal operating conditions
Step.
Preferably, initial stage, adjusting stage and locked stage are divided with corresponding preset duration, i.e., this is pre-
If condition is to adjust phase duration to reach corresponding preset duration.In specific practical application, can according to analysis or
Person tests to obtain suitable preset duration, then is configured by preset duration of the control unit to each stage；For example, first
In stage beginning, the output of control unit is so that on-off switch K1 is held off；After a few tens of milliseconds after initial stage starting,
Control unit is started to work, and controls on-off switch K1 discontinuous conduction, Switching Power Supply is made to enter the adjusting stage；By adjusting the stage one
The adjusting of section preset duration, can be several milliseconds by several seconds, sets according to actual needs, the width of voltage sampling signal
Degree should be less than predetermined amplitude, and (electric main AC is subtracted on first resistor R1 and second resistance R2 the voltage on filter capacitor C
Partial pressure) it is stepped up to suitable voltage, rear class converter will enter normal operating conditions, and control unit control on-off is opened at this time
Closing after K1 is connected is normal open, makes the Switching Power Supply that will enter locked stage.
Alternatively, the amplitude that the preset condition is voltage sampling signal is less than predetermined amplitude, i.e., locked stage is with voltage sample
The amplitude of signal VS1 is initial time at the time of being less than predetermined amplitude.The amplitude of voltage sampling signal VS1 is less than predetermined amplitude,
Illustrate that the voltage on filter capacitor C has been raised to suitable voltage, rear class converter can enter normal operating conditions, and control is single
Member, which will control the Switching Power Supply, will enter locked stage.
Division for above-mentioned each stage can be set according to specific actual application environment by control unit
It is fixed, it is not specifically limited herein, within the scope of protection of this application.
It is worth noting that there is also technical solutions shown in Fig. 4 in the prior art: when switch K0 closure, power supply electrifying
When, it is remained open by delay unit control switch K1 first, then electric main AC is wrapped in the charge circuit of filter capacitor C
Contain a series resistance R, the resistance value of this resistance R generally selects several hundred ohms, it is sufficient to the amplitude of charging current is limited, thus
Inhibit to generate excessive power-on surge current and booting surge voltage.After a delay time of delay unit setting, prolong
Control switch K1 is closed Shi Danyuan again, to reduce issuable excessive power consumption on resistance R.After this, rear class converter
It starts to work, rear class converter operating current required when working flows through switch K1, and without resistance R.But it is shown in Fig. 4
In prior art, when switch K1 is through timing closing, the impedance of charge circuit becomes smaller again, still can generate one it is slightly smaller
Surge current.
Compared with prior art, the soft starting circuit of the Switching Power Supply provided in this embodiment, passes through the control unit
Control, so that in the above-mentioned each stage of Switching Power Supply after power-up, charging current on filter capacitor C is smaller, fills
Piezoelectric voltage can be stepped up, and then realized and significantly inhibited the power-on surge current amplitude of Switching Power Supply, meanwhile, make
Slowly rising is presented in the voltage at the both ends filter capacitor C needed for obtaining the work of rear class converter, to also eliminate filter capacitor C
The surge voltage overshoot phenomenon at both ends.It is not in that electronic device bears excessive current stress or electricity in this control process
The case where compression, that is, can be improved the reliability of power supply product by above-mentioned soft start-up process.
It is worth noting that can be realized the control unit of above-mentioned function, it can be and carried out not according to specific application environment
With the diversified forms being specifically arranged, in particular for the default rule in the stage of adjusting, the specific implementation form of the control unit can
There are many.
For example, referring to Fig. 6, on-off switch K1 and 3rd resistor R3 are concatenated on the basis of above-described embodiment and Fig. 5
Tie point is connected with the second input terminal of control unit；
At this point, the control signal is that control unit is defeated according to the received voltage sampling signal VS1 and second of first input end
Enter to hold received current sampling signal VS2 and generates；
Corresponding default rule are as follows: when voltage sampling signal VS1 drops to reference voltage reference signal, control on-off is opened
Close K1 conducting；And in current sampling signal VS2 zero passage, control on-off switch K1 shutdown.
Specifically, urban electric power switch K0 closure, control unit is not yet started to work at this time, and control unit is defeated in the initial stage
Control signal out is low level, and on-off switch K1 is off state.In this stage, electric main AC fills filter capacitor C
First resistor R1 and second resistance R2 are contained in electrical circuit, since the sum of the resistance value of first resistor R1 and second resistance R2 compare
Greatly, it is more than or equal to 100 kilohms, such as 1 megohm or more, so that it is very small to the charging current of filter capacitor C, less than 1 milli
Peace.Therefore, so that being completely absent power-on surge current in the moment of electric main AC access；Simultaneously as first resistor R1
With the big resistance value of second resistance R2, so that the time constant to charge to filter capacitor C is very big, thus filter capacitor C is slow
Charging, voltage thereon slowly rise, to completely eliminate the instantaneous surge voltage overshoot phenomenon that is switched on.
Fig. 7 show the Switching Power Supply in the signal waveforms of initial stage, and the sinusoidal voltage of electric main AC is (in Fig. 7
First waveform) through filter inductance L, rectifier bridge, concatenated first resistor R1 and second resistance R2, charge to filter capacitor C,
The sum of resistance value due to first resistor R1 and second resistance R2 is larger, charging current very little, and charge circuit have it is biggish when
Between constant so that the process (second waveform in Fig. 7) that slowly rises is presented in the voltage at the both ends filter capacitor C.
Since electric main AC is power frequency (50 or 60 hertz), the pressure drop on High frequency filter inductance L be can be ignored, whole
The conduction voltage drop of rectifier diode in stream bridge can be ignored.Thus, in the case where on-off switch K1 is held off,
One end can be expressed as AC sine to the voltage at the voltage namely filter capacitor C and first resistor R1 tie point on reference ground
Line voltage (through over commutation) subtracts the voltage that filter capacitor C both end voltage obtains, i.e. third waveform in Fig. 7.This wave
The feature of shape be a local sinusoidal wave with dead time through over commutation, and with filter capacitor C due to charging and
Caused both end voltage gradually rises, and the dead time of this local sinusoidal wave is gradually increased, amplitude is gradually reduced.
The 4th waveform in Fig. 7 is the voltage wave at the first sampling resistor R1 and second resistance R2 tie point to reference ground
Shape, namely give to the waveform of the voltage sampling signal VS1 of control unit first input end, it is third waveform warp in Fig. 7
Cross the waveform obtained after the simple partial pressure of first resistor R1 and second resistance R2.
In this initial stage, since the control signal of control unit output keeps low level, so that on-off switch K1 is kept
Off state, thus with the concatenated current sampling resistor of on-off switch K1, i.e. 3rd resistor R3, the signal sampled is always
Zero, that is, sending the current sampling signal VS2 to the second input terminal of control unit is always zero.Current sampling signal VS2 is one
The signal of the current value of on-off switch K1 is flowed through by voltage value characterization.
In the above-mentioned initial stage, the surge current and surge voltage of booting moment, but Switching Power Supply have been completely eliminated
It also needs that rear class converter is allowed to start to work, and to realize any time section before the start-up operation of rear class converter,
It is not in surge current and surge voltage.Therefore, it is necessary to so that the Switching Power Supply is entered the next adjusting stage.
In specific practical application, can by control unit after the delay waiting time appropriate, such as a few tens of milliseconds,
It starts to work, Switching Power Supply is made to enter the adjusting stage.
When control unit is started to work, adjusting stage specific timing waveform is referring to Fig. 8.The switch electricity described in conjunction with Fig. 5
The structural schematic diagram in source, each waveform in Fig. 8 are described as follows:
#1 waveform is the voltage waveform of the received electric main AC of Switching Power Supply；
#2 waveform is the current waveform of the received electric main AC of Switching Power Supply；
#3 waveform is the voltage waveform at the both ends filter capacitor C, this voltage is used to power to rear class converter；
The opposite voltage waveform with reference to ground in one end that #4 waveform is on-off switch K1, i.e. filter capacitor C and first resistor R1
To the voltage waveform on reference ground at tie point；
#5 waveform is to be sent after electric resistance partial pressure to the voltage sampling signal VS1 waveform of control unit first input end；
#6 waveform is the waveform of the control signal of control unit output, which send to the control of on-off switch K1
End；
#7 waveform be with the voltage signal namely current sampling signal VS2 on the concatenated 3rd resistor R3 of on-off switch K1,
It send to the second input terminal of control unit；
In the adjusting stage, the control signal of output is kept low level first by control unit, so that on-off switch K1 is kept
Off state, while the decline process of monitoring voltage sampled signal VS1.The voltage sampling signal VS1 that control unit will receive
It is compared with the reference voltage reference signal Vref1 inside control unit, sees the 5th waveform in Fig. 8.
When there is voltage sampling signal VS1 lower than reference voltage reference signal Vref1 signal, when t1 in corresponding diagram 8
It carves, the control signal of control unit output becomes high level, so that on-off switch K1 enters on state.When on-off switch K1 is protected
When holding on state, due to the conducting resistance very little of on-off switch K1, while the resistance value of 3rd resistor R3 connected in series is also very
It is small, so that the current potential of one end of on-off switch K1 is pulled down to no better than reference ground, thus first resistor R1 and second resistance
R2 is almost grounded, and voltage sampling signal VS1 is approximately equal to zero.
Since the t1 moment, the control signal of control unit output is converted to high level, which makes on-off switch
K1 enters on state, and electric main AC generates charging to filter capacitor C due to the conducting of on-off switch K1 therewith.Due to third
Resistance R3 connects with on-off switch K1's, so that the charging current generates a current sampling signal VS2 on 3rd resistor R3,
The signal is sent to the second input terminal of control unit.It is upper with filter capacitor C both end voltage in above-mentioned charging process
It rises, charging current is gradually reduced.When filter capacitor C both end voltage is charged to voltage value identical with electric main AC, fill
Electric process terminates, and charging current drops to zero.Control unit monitors reflection charging current variation always during recharging here
Current sampling signal VS2.At the time of current sampling signal VS2 drops to zero, the control signal of control unit output is generated
Low level, to close on-off switch K1.
The control signal exported from control unit is converted to t1 at the time of on-off switch K1 is connected in high level, until
The control signal of control unit output is converted to the t2 moment that low level turns off on-off switch K1, and this period is exactly on-off
The turn-on time of switch K1, referred to as Ton.The above process may refer to #5, #6, #7 waveform in Fig. 8.
At the above-mentioned t1 moment, i.e. voltage sampling signal VS1 will begin lower than reference voltage reference signal Vref1 when
It carves, on-off switch K1 will be begun to turn at this time, but be not yet connected.At this time since voltage sampling signal VS1 is a positive electricity
Signal is pressed, and voltage of the voltage sampling signal VS1 from the one end on-off switch K1 passes through first resistor R1 and second resistance R2
Partial pressure, it means that at the t1 moment, to reference there are a positive voltages for one end of on-off switch K1.Referring to Fig. 5, on-off is opened
The one end K1 is closed to the voltage on reference ground, subtracts the voltage that filter capacitor C both end voltage obtains equal to electric main AC voltage, then subtract
Filter inductance L and rectifier bridge pressure drop are removed, and filter inductance L and rectifier bridge pressure drop are relatively very low to ignore, accordingly, it is to be understood that
For, at the t1 moment, the one end on-off switch K1 to the voltage value on reference ground characterize the instantaneous voltage of electric main AC this moment with
The difference of the both ends filter capacitor C voltage value this moment.The voltage sampling signal VS1 that control unit monitors as a result, is positive voltage, is said
The instantaneous value of the bright AC of electric main at the moment is greater than the voltage value at the both ends filter capacitor C, and its difference can be by following formula table
It reaches:
Vac (t1)-Vc (t1)=Vref1 × (1+R1/R2)
Wherein, Vac (t1) indicates the instantaneous voltage in t1 moment electric main AC, and Vc (t1) expression filters at the t1 moment
The voltage value at the both ends capacitor C.
According to above formula, at the t1 moment, there are voltage difference Vac (t1)-between electric main AC and filter capacitor C both end voltage
And then Vc (t1) therefore, makes on-off switch K1 enter conducting when the control signal of control unit output is converted to high level
When state, an electric main AC will necessarily be generated to the charging process and a corresponding charging current of filter capacitor C.
According to above formula, since reference voltage reference signal Vref1 is the constant a reference value for constant, such as 1.2, so that should
Voltage difference Vac (t1)-Vc (t1) is only dependent upon the ratio between the resistance value of first resistor R1 and second resistance R2.Therefore, it properly selects
The ratio between resistance value of first resistor R1 and second resistance R2 be a smaller value, i.e., by resistance value selection make first resistor R1 and
The ratio between resistance value of second resistance R2 is less than default ratio, so that it may the result of above-mentioned voltage difference Vac (t1)-Vc (t1) be allowed to be one
For smaller value, which means that when on-off switch K1 is instantaneous in conducting, electric main AC instantaneous voltage compares filter capacitor C
Both end voltage instantaneous value exceeds simultaneously few, such as preset pressure described in only 10 volts or 20 volts namely above-described embodiment.
The charging current thus generated during the charging process therewith will not be big, and the peak value of charging current will not be high, such as peak value only has
Tens milliamperes, this assures will not generate surge current.In specific practical application, first resistor R1 and second resistance
The ratio between resistance value of R2 can be 10,20 or 30 etc., as long as being less than default ratio, such as less than 50, and it does not do herein specific
It limits；Preferably, the resistance value of first resistor R1 can select 2.7 megaohms, the resistance value of second resistance R2 can select 240 kilo-ohms；Specifically
It can also be depending on its application environment, within the scope of protection of this application.
Similarly, so small charging current, it is meant that smaller energy, to filter capacitor C charging as a result, only allowing
The voltage at the both ends filter capacitor C has a smaller Spline smoothing, sees #3 waveform in Fig. 8, from t1 to t2 during variation, this
It eliminates the need for filter capacitor C both end voltage and the phenomenon that surge voltage overshoot occurs.
According to the description above, the charging current that charging process generates is smaller, even if there is filtering in charge circuit
Inductance L, energy storage can also release within the shorter time.As can see from Figure 8, #2 waveform tracing electric main
The current waveform that AC is provided.Charging current is generated since the t1 moment, when arriving the t2 moment, which has decreased to zero.
Therefore at the end of the t2 moment, the i.e. turn-on time Ton of on-off switch K1, inductive energy storage, on-off switch are not present in circuit
When K1 enters off state, the both ends on-off switch K1 are not in back-emf, belong to safe shutdown.
Since the t2 moment, the control signal of control unit output is converted to low level, closes on-off switch K1, and control is single
Member starts to detect voltage sampling signal VS1 again, ignores voltage sampling signal VS1 by hysteresis comparator realization in control unit
Uphill process, and the only decline process of monitoring voltage sampled signal VS1, until enter next moment t3, control unit
It monitors that voltage sampling signal VS1 is lower than the state of reference voltage reference signal Vref1 again, thus opens next week
The judgement and control process of phase.
As depicted in fig. 8, control unit detects voltage sampling signal VS1 and current sampling signal VS2 periodically one by one, by
A conducting and shutdown for controlling on-off switch K1 periodically.This process is synchronized with the sinusoidal character of electric main AC, and on-off is opened
Some period of K1 during its both end voltage declines is closed, conducting and shutdown are implemented, is connected in each period on-off switch
Period, electric main AC are presented smaller amplitude to the charging current of filter capacitor C, filter capacitor C both end voltage present by
The step in a period climbs, and such operating mode is completely eliminated surge current and surge voltage when booting.
In the stage of adjusting, starting of the control unit inside the rising edge for controlling each high level of signal, Simultaneous Monitoring is fixed
When device state, when determine the state be significant level when, then circuit device will enter lower locked stage.
Control unit includes a starting timer, and when control unit is started to work, which also starts work
Make.Start timer and set a delay time, for determining when Switching Power Supply from the adjusting stage above-mentioned enters lock step
Section.A high level will be persistently maintained in the control signal of locked stage, control unit output, so that on-off switch K1 mono-
Straight to maintain on state, such filter capacitor C both end voltage is exactly the voltage after electric main AC is rectified, so that rear class
Converter can start to work.
From phase transition is adjusted to locked stage, the waveform of each operating point may refer to Fig. 9.On the basis of Fig. 8,
Increased #8 waveform describes the output signal of starting timer.When the timing for starting timer reaches, starting timing
Device exports the enabled useful signal of a high level.Control unit is gone in the rising edge time that control signal is high level every time
Latch the current state of the output signal of starting timer.When the current state being latched into is invalid low level, control is single
The control signal of member output will adjust the operating mode in stage before maintaining.If the current state being latched into is effective high electricity
Usually, then the control signal of control unit output will persistently export high level, so that on-off switch K1 maintains always on state,
Switching Power Supply is set to enter locked stage.
According to the description of Fig. 9, at t1 the and t3 moment, the control signal of control unit output is converted to the rising edge of high level
Moment, it is corresponding starting timer output state (#8 waveform) be low level, thus control unit output control signal meeting
Become low level, i.e. t2, t4 moment in current sampling signal VS2 zero passage, and then turns off on-off switch K1.
An optional t5 moment, the output state for starting timer becomes high level.At this point, control can't allow at once
The control signal of unit output processed is converted to high level, but needs the rising edge for controlling signal until the t6 moment to be just latched into and open
The state of dynamic timer.Since the t6 moment, control signal maintains high level always, and switch unit enters locked stage.
At the subsequent t7 moment, charging current falls to zero, and controls signal due to locked, so continuing to high electricity
It is flat.
Again then, electric main AC voltage zero-cross.Then, with the rising again of electric main AC, until t8 moment, exchange
When commercial AC voltage is more than filter capacitor C both end voltage, the charging current to filter capacitor C is generated again.Due to electric main
AC starts from scratch slowly to be risen according to sine, this makes current charging current that smaller amplitude be presented, and sees #2 in Fig. 9
T8 to the t9 period of waveform.
According to foregoing description, it can be understood as, the output state for starting timer is controlled unit with its control signal
Rising edge synch sampling, that is to say, that at the time of on-off switch K1 enters normal open state, any big charging will not be generated
Electric current.Therefore, this circuit device is transferred to locked stage from the adjusting stage, will not equally generate big surge current and surge electricity
Pressure.
Preferably, referring to Figure 10, which includes: the second hysteresis comparator U1, the first zero-crossing comparator, second opens
Dynamic timer, edge triggered flip flop, the second d type flip flop and second or door；Wherein:
The non-inverting input terminal of second hysteresis comparator U2 receives voltage sampling signal VS1；
The inverting input terminal of second hysteresis comparator U2 receives reference voltage reference signal；
The output end of second hysteresis comparator U2 is connected with the set end of edge triggered flip flop；
The input terminal of first zero-crossing comparator receives current sampling signal VS2；
The output end of first zero-crossing comparator is connected with the reset terminal of edge triggered flip flop；
The output end of second starting timer is connected with the data terminal of the second d type flip flop；
The output end of edge triggered flip flop and the rising edge triggering end of the second d type flip flop and second or door an input terminal phase
Even；
The output end of second d type flip flop is connected with another input terminal of second or door；
Second or door output end output control signal.
This can be using edge triggered flip flop as edge type rest-set flip-flop.
Control unit includes a hysteresis comparator, for receiving voltage sampling signal VS1, by this voltage sampling signal
VS1 is compared with reference voltage reference signal Vref1, and the output result of second hysteresis comparator U2 is sent to an edge and touched
Send out the set end Set of device.When occurring during the decline of voltage sampling signal VS1 lower than reference voltage reference signal Vref1,
The second hysteresis comparator U2 exports a low level, and the failing edge which occurs makes the output end Q1 of edge triggered flip flop
It is set to high level, makes control signal be converted to high level through second or door, so that on-off switch K1 be made to enter on state.
When on-off switch K1 is begun to turn on, generate a charging current to filter capacitor C, the charging current pass through with
The current sampling signal VS2 obtained on on-off switch K1 concatenated 3rd resistor R3,3rd resistor R3 pass through control unit the
Two input terminals are sent to the first zero-crossing comparator.When charging current falls to zero, i.e. current sampling signal VS2 falls to zero
When, the first zero-crossing comparator generates a failing edge from high to low, which send answering to aforementioned edge triggered flip flop
Position end Reset makes control signal be converted to low electricity so that the output end Q1 of edge triggered flip flop is set to low level through second or door
It is flat, so that on-off switch K1 be made to enter off state.
Thereafter, control unit again initially waits for the decline process of voltage sampling signal VS1, hence into next cycle
Judgement.
Control unit also includes one second starting timer, sets a delay waiting time, for determining control
When unit processed from the adjusting stage above-mentioned enters locked stage.The delay waiting time of second starting timer setting can be
Several milliseconds were set according to actual needs by several seconds, were not specifically limited herein, within the scope of protection of this application.
Second starting timer has an output signal, indicates that control unit is still in when which is low level and adjusts rank
Section.When the signal becomes high level, indicate that the delay waiting time has terminated, control unit will enter locked stage.
The output signal of second starting timer is sent to the data terminal D of second d type flip flop, second d type flip flop
Rising edge triggering end CK receives output end Q1, the output end Q2 of second d type flip flop of the signal from aforementioned edge triggered flip flop
Send another input terminal to aforementioned second or door.
When second starting timer the delay waiting time not yet at the end of, second starting timer output be low electricity
Flat, this makes the data terminal D of the second d type flip flop be low level.It exports from edge triggered flip flop output end Q1 to the 2nd D and triggers
The level signal that each rising edge of the rising edge triggering end CK of device is latched into second d type flip flop is low level, because
And the output end Q2 signal of second d type flip flop is low level.Due to second or door, so that the level change of control signal is only
Signal depending on edge triggered flip flop output end Q1.
At the end of the delay waiting time of the second starting timer, the output of the second starting timer becomes high level,
This makes the data terminal D of the second d type flip flop also become high level, this high level signal will not allow at once the second d type flip flop defeated
Height is set out, but the rising edge triggering end CK of the second d type flip flop to be waited rising edge signal occur.It is touched when from aforementioned edge
The signal of hair device output end Q1 becomes the high level moment, and rising edge occurs in the rising edge triggering end CK of the second d type flip flop, thus will
The high level of the data terminal D of second d type flip flop is latched, so that the signal of the second d type flip flop output end Q2 becomes high level.
The high level signal of second d type flip flop output end Q2 enters or door, so that control signal remains high level.Hereafter, due to
The output of two starting timers keeps high level constant, so that control signal also maintains high level.In this way, control unit enters
Locked stage, on-off switch K1 also maintain always on state.
So far, since soft starting circuit provided in this embodiment complete initial stage, adjusting stage, locking powering on
The rear class converter of the overall process in stage, power supply is started to work.
Alternatively, another embodiment of the present invention additionally provides another specific Switching Power Supply only on the basis of Fig. 5
Soft starting circuit, preset rule are as follows: when voltage sampling signal VS1 drops to reference voltage reference signal, control on-off
Switch K1 conducting；And after default conducting duration, control on-off switch K1 shutdown.
At this point, control unit exports the condition of high level in the adjusting stage, and it is consistent with aforementioned schemes, also in voltage
At the time of the failing edge of sampled signal VS1 is occurred lower than reference voltage reference signal Vref1, the t1 moment in Figure 11 is seen；Institute is not
With, after the t1 moment, control signal, which is kept for the time of high level, to be determined by the timer of a constant time lag time,
See in Figure 11 that the Ton for representing control signal high level lasting time length is fixed and invariable, i.e., from the t1 moment to the t3 moment
Default conducting duration, and should be ensured that in the default preferable situation of conducting duration of this fixation greater than current sampling signal
The time of VS2 zero passage, i.e. t1 moment to the t2 moment.
Since the t1 moment, control signal is high level, and on-off switch K1 conducting, electric main AC generation is to filter capacitor
The charging current of C；With the reduction of charging current, at the t2 moment, current sampling signal VS2 falls to zero, shows charging current
It is over；But control signal still maintains high level, until at the next t3 moment, just make control signal become low electricity
It is flat, to turn off on-off switch K1.Next, control unit restarts to detect the failing edge process of voltage sampling signal VS1,
To enter the control process in next period.
Since t2 moment charging current has been subjected to zero end, the t3 moment behind turns off on-off switch K1 and still falls within peace
Full shutdown.
Timing for this default conducting duration Ton fixed can be located at monostable inside control unit by one
State timer realizes that defined default conducting duration Ton can be in 100 microseconds to 500 microsecond ranges.It is filled due to aforementioned
The amplitude of electric current is smaller, so that the time of charging current decline zero passage is shorter, the timer time of 100 to 500 microseconds is
Enough.
As described herein is the control process in adjusting stage, for locked stage judgement control, then with aforementioned schemes
It is identical, it is not repeating here.
Preferably, referring to Figure 12, control unit includes: the first hysteresis comparator U1, the first starting timer, first monostable
State timer, the first d type flip flop and first or door；Wherein:
The non-inverting input terminal of first hysteresis comparator U1 receives voltage sampling signal VS1；
The inverting input terminal of first hysteresis comparator U1 receives reference voltage reference signal；
The output end of first hysteresis comparator U1 is connected with the input terminal of the first monostable timing device；
The output end of first starting timer is connected with the data terminal of the first d type flip flop；
The output end of first monostable timing device and the rising edge triggering end of the first d type flip flop and first or one of door it is defeated
Enter end to be connected；
The output end of first d type flip flop is connected with another input terminal of first or door；
First or door output end output control signal.
More preferably, on the basis of Fig. 5, referring to Fig. 6, on-off switch K1 and the concatenated tie point of 3rd resistor R3
It is connected with the second input terminal of control unit；
At this point, the control signal is that control unit is defeated according to the received voltage sampling signal VS1 and second of first input end
Enter to hold received current sampling signal VS2 and generates；
Corresponding default rule are as follows: when voltage sampling signal VS1 drops to reference voltage reference signal, control on-off is opened
Close K1 conducting；And after default conducting duration or when current sampling signal VS2 zero passage, control on-off switch K1 shutdown.
At this time, it is preferred that referring to Figure 13, control unit includes: third hysteresis comparator U3, the second zero-crossing comparator,
Three starting timers, the second monostable timing device, third d type flip flop, third or door U4 and the 4th or door U5；Wherein:
The non-inverting input terminal of third hysteresis comparator U3 receives voltage sampling signal VS1；
The inverting input terminal of third hysteresis comparator U3 receives reference voltage reference signal；
The output end of third hysteresis comparator U3 is connected with the input terminal of the second monostable timing device；
The output end of second monostable timing device is connected with an input terminal of third or door U4；
The input terminal of second zero-crossing comparator receives current sampling signal VS2；
The output end of second zero-crossing comparator is connected with another input terminal of third or door U4；
The output end of third starting timer is connected with the data terminal of third d type flip flop；
The output end of third or door U4 and the rising edge triggering end of third d type flip flop and an input terminal of the 4th or door U5
It is connected；
The output end of third d type flip flop is connected with another input terminal of the 4th or door U5；
The output end output control signal of 4th or door U5.
Control unit includes the second monostable timing device of an edging trigger.When control unit monitors that voltage sample is believed
When the decline process of number VS1 is occurred lower than reference voltage reference signal Vref1, third hysteresis comparator U3 exports an effectively electricity
Flat edge variation, send to the triggering input terminal of the second monostable timing device, so that the output terminals A horse of the second monostable timing device
On set high level, make to control signal through third or door U4 and set high level, at the same time, it is pre- that the second monostable flipflop starts starting
If the timing of duration Ton is connected.
At this point, current sampling signal VS2 is still admitted to second zero-crossing comparator, and its to compare output B also same
Sample makes control signal set high level through third or door U4.When current sampling signal VS2 zero passage, the second zero-crossing comparator exports B
Set low level, but since the timing of the second monostable timing device at this time not yet terminates, i.e. the signal at the end A remains as in Figure 13
High level, thus make control signal remain as high level by third or door U4, on-off switch K1 is tended to remain on.
When the timing of the second monostable timing device reaches, the signal at the end A becomes low level, due at this time second
The signal of zero-crossing comparator output end B becomes low level in advance, this makes the control signal after third or door U4 become low
Level, to turn off on-off switch K1.
In this scheme, since the timing of the second monostable timing device is configured to ensure to be greater than current sampling signal
The time of zero passage occurs for VS2, this makes, and under normal circumstances, current sampling signal VS2 and the second zero-crossing comparator result are not
Directly affect the level change of control signal.But in order to prevent in extreme circumstances, current sampling signal VS2 occur zero passage when
Between be greater than the monostable timing time, thus, more preferably than Figure 12, referring to Figure 13, current sampling signal VS2 and the second zero passage
Comparator still retains, at this point, it is still by current sample that control signal, which changes into low level condition, due to third or door U4
Signal VS2 zero passage and determine.
It is worth noting that the control unit can be realized by IC chip in above-described embodiment, such as will
Hardware circuit shown in Figure 10, Figure 12 and Figure 13 is set to ic core on piece, or can also be with one together with on-off switch K1
With ic core on piece is set to, it is not specifically limited herein, it can be depending on its specific application environment, the application's
In protection scope.
In addition, single-chip microcontroller, PLC (Programmable Logic can also be used in specific practical application
Controller, programmable logic controller) etc. software controllers replace above-mentioned hardware circuit to realize the control unit
Function is not specifically limited herein, can be depending on its specific application environment, within the scope of protection of this application.
Another embodiment of the present invention additionally provides a kind of Switching Power Supply, referring to Fig. 5 or Fig. 6, comprising: filter inductance L, alternating current
Switch K0, rectifier bridge, filter capacitor C, rear class converter and any of the above-described embodiment Switching Power Supply soft starting circuit；Its
In:
Electric main AC passes through filter inductance L and urban electric power switch K0 respectively and is connected with two input terminals of rectifier bridge；
The output head anode of rectifier bridge passes sequentially through the soft starting circuit of filter capacitor C and Switching Power Supply, with rectifier bridge
Negative pole of output end is connected with reference to ground；
Rear class converter is in parallel with filter capacitor C.
Preferably, rear class converter are as follows: flyback topologies, buck topology or buck topology, depending on it particularly due to environment
Depending on, within the scope of protection of this application.
Specific working principle is same as the previously described embodiments, no longer repeats one by one herein.
Each embodiment is described in a progressive manner in the present invention, the highlights of each of the examples are with other realities
The difference of example is applied, the same or similar parts in each embodiment may refer to each other.For device disclosed in embodiment
Speech, since it is corresponded to the methods disclosed in the examples, so being described relatively simple, related place is referring to method part illustration
?.
The above is only the preferred embodiment of the present invention, make skilled artisans appreciate that or realizing of the invention.It is right
A variety of modifications of these embodiments will be apparent to one skilled in the art, general original as defined herein
Reason can be realized in other embodiments without departing from the spirit or scope of the present invention.Therefore, the present invention will not
Be intended to be limited to the embodiments shown herein, and be to fit to it is consistent with the principles and novel features disclosed in this article most
Wide range.
Claims (10)
1. a kind of soft starting circuit of Switching Power Supply, which is characterized in that be connected to the filter capacitor of Switching Power Supply and with reference to ground
Between；The soft starting circuit of the Switching Power Supply includes: control unit, on-off switch, first resistor, second resistance and third electricity
Resistance；Wherein:
The first resistor and the second resistance are connected in series between the filter capacitor and reference ground, concatenated tie point
It is connected with the first input end of described control unit；
The on-off switch and the 3rd resistor are connected in series in the filter capacitor and with reference between ground；
The second resistance with reference is connected with the 3rd resistor；
The sum of resistance value of the first resistor and the second resistance is more than or equal to 100 kilohms；
Described control unit is used to generate control signal according to the received voltage sampling signal of first input end and export to described
The control terminal of on-off switch, to make the on-off switch be held off shape in the initial stage after the Switching Power Supply powers on
State controls the on-off switch within the adjusting stage after the Switching Power Supply powers on to preset regular turn-on and turn-off, make
The filter capacitor charges under preset pressure by phased manner, and controls the on-off switch on the filter capacitor
Voltage meet preset condition after, the Switching Power Supply power on after locked stage in tend to remain on after conducting.
2. the soft starting circuit of Switching Power Supply according to claim 1, which is characterized in that the initial stage, the tune
Section stage and the locked stage are divided with corresponding preset duration；
Alternatively, the amplitude that the preset condition is the voltage sampling signal is less than predetermined amplitude.
3. the soft starting circuit of Switching Power Supply according to claim 1, which is characterized in that the first resistor and described the
The ratio between resistance value of two resistance is less than default ratio.
4. the soft starting circuit of Switching Power Supply according to claim 1, which is characterized in that the default rule are as follows: in institute
When stating voltage sampling signal and dropping to reference voltage reference signal, the on-off switch conducting is controlled；And in default conducting duration
Later, the on-off switch shutdown is controlled.
5. the soft starting circuit of Switching Power Supply according to claim 1, which is characterized in that the on-off switch and described the
The concatenated tie point of three resistance is connected with the second input terminal of described control unit；
The control signal is that described control unit is terminated according to the received voltage sampling signal of first input end and the second input
The current sampling signal of receipts and generate；
The default rule are as follows: when the voltage sampling signal drops to reference voltage reference signal, control the on-off and open
Close conducting；And in the current sampling signal zero passage, the on-off switch shutdown is controlled；
Alternatively, the default rule are as follows: when the voltage sampling signal drops to reference voltage reference signal, control described logical
Disconnected switch conduction；And after default conducting duration or when the current sampling signal zero passage, controls the on-off switch and close
It is disconnected.
6. the soft starting circuit of Switching Power Supply according to claim 4, which is characterized in that described control unit includes:
One hysteresis comparator, the first starting timer, the first monostable timing device, the first d type flip flop and first or door；Wherein:
The non-inverting input terminal of first hysteresis comparator receives the voltage sampling signal；
The inverting input terminal of first hysteresis comparator receives the reference voltage reference signal；
The output end of first hysteresis comparator is connected with the input terminal of the first monostable timing device；
The output end of the first starting timer is connected with the data terminal of first d type flip flop；
The rising edge triggering end of the output end of the first monostable timing device and first d type flip flop and described first or door
An input terminal be connected；
The output end of first d type flip flop is connected with another input terminal of described first or door；
Described first or the output end of door export the control signal.
7. the soft starting circuit of Switching Power Supply according to claim 5, which is characterized in that the default rule are as follows: in institute
When stating voltage sampling signal and dropping to reference voltage reference signal, the on-off switch conducting is controlled；And in the current sample
When signal zero passage, when controlling on-off switch shutdown, described control unit includes: the second hysteresis comparator, the first zero passage ratio
Compared with device, the second starting timer, edge triggered flip flop, the second d type flip flop and second or door；Wherein:
The non-inverting input terminal of second hysteresis comparator receives the voltage sampling signal；
The inverting input terminal of second hysteresis comparator receives the reference voltage reference signal；
The output end of second hysteresis comparator is connected with the set end of the edge triggered flip flop；
The input terminal of first zero-crossing comparator receives the current sampling signal；
The output end of first zero-crossing comparator is connected with the reset terminal of the edge triggered flip flop；
The output end of the second starting timer is connected with the data terminal of second d type flip flop；
The rising edge triggering end and described or door the input of the output end of the edge triggered flip flop and second d type flip flop
End is connected；
The output end of second d type flip flop is connected with another input terminal of described second or door；
Described second or the output end of door export the control signal；
The default rule are as follows: when the voltage sampling signal drops to reference voltage reference signal, control the on-off and open
Close conducting；And after default conducting duration or when the current sampling signal zero passage, the on-off switch shutdown is controlled
When, described control unit includes: third hysteresis comparator, the second zero-crossing comparator, third starts timer, the second monostable is determined
When device, third d type flip flop, third or door and the 4th or door；Wherein:
The non-inverting input terminal of the third hysteresis comparator receives the voltage sampling signal；
The inverting input terminal of the third hysteresis comparator receives the reference voltage reference signal；
The output end of the third hysteresis comparator is connected with the input terminal of the second monostable timing device；
The output end of the second monostable timing device is connected with an input terminal of the third or door；
The input terminal of second zero-crossing comparator receives the current sampling signal；
The output end of second zero-crossing comparator is connected with another input terminal of the third or door；
The output end of the third starting timer is connected with the data terminal of the third d type flip flop；
The output end of the third or door and the rising edge triggering end of the third d type flip flop and the described 4th or one of door it is defeated
Enter end to be connected；
The output end of the third d type flip flop is connected with another input terminal of the described 4th or door；
Described 4th or the output end of door export the control signal.
8. the soft starting circuit of Switching Power Supply according to any one of claims 1 to 5, which is characterized in that described control unit
Are as follows: single-chip microcontroller or programmable logic controller PLC.
9. the soft starting circuit of Switching Power Supply according to any one of claims 1 to 7, which is characterized in that described control unit
It is set to ic core on piece or described control unit and the on-off switch is all set in ic core on piece.
10. a kind of Switching Power Supply characterized by comprising filter inductance, urban electric power switch, rectifier bridge, filter capacitor, rear class become
The soft starting circuit of parallel operation and any Switching Power Supply of claim 1 to 9；Wherein:
Electric main is connected by the filter inductance and the urban electric power switch with two input terminals of the rectifier bridge respectively；
The output head anode of the rectifier bridge passes sequentially through the soft starting circuit of the filter capacitor and the Switching Power Supply, with institute
The negative pole of output end for stating rectifier bridge is connected with reference；
The rear class converter is in parallel with the filter capacitor.
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| JP2020150727A (en) * | 2019-03-14 | 2020-09-17 | オムロン株式会社 | Power supply |
| CN112782448A (en) * | 2020-12-30 | 2021-05-11 | 西华大学 | Current source input conversion device |
| CN113794367A (en) * | 2021-09-13 | 2021-12-14 | 深圳威迈斯新能源股份有限公司 | Power supply with anti-surge function, control method thereof and vehicle-mounted charger |
| WO2022160207A1 (en) * | 2021-01-28 | 2022-08-04 | 华为数字能源技术有限公司 | Conversion circuit, pre-charging control method for conversion circuit, and photovoltaic system |
| CN114900034A (en) * | 2022-07-07 | 2022-08-12 | 山西省智慧交通研究院有限公司 | Low-frequency filtering method at power interface of communication equipment |
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| CN112782448B (en) * | 2020-12-30 | 2022-01-18 | 西华大学 | Current source input conversion device |
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| CN115015797A (en) * | 2022-08-08 | 2022-09-06 | 深圳市恒运昌真空技术有限公司 | Method and device for collecting radio frequency power supply signal |
| CN115015797B (en) * | 2022-08-08 | 2022-10-14 | 深圳市恒运昌真空技术有限公司 | Radio frequency power supply signal acquisition method and device |
| CN115864814A (en) * | 2023-02-27 | 2023-03-28 | 阳光电源股份有限公司 | Soft start circuit and power conversion equipment |
| CN115864814B (en) * | 2023-02-27 | 2023-05-30 | 阳光电源股份有限公司 | Soft start circuit and power conversion equipment |
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Application publication date: 20181225 |