CN106329483B - Switching Power Supply - Google Patents
Switching Power Supply Download PDFInfo
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- CN106329483B CN106329483B CN201510367472.5A CN201510367472A CN106329483B CN 106329483 B CN106329483 B CN 106329483B CN 201510367472 A CN201510367472 A CN 201510367472A CN 106329483 B CN106329483 B CN 106329483B
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Abstract
The present invention provides a kind of Switching Power Supply for the rank that can switch overcurrent protection action on startup, is suitable for having bigger capacitive load so that can select suitable Switching Power Supply according to the principle that the power consumption of output power and load circuit matches.The Switching Power Supply includes：Power supply main part, rectifying and wave-filtering is carried out to industrial power to handle to obtain first voltage signal, transformation processing is carried out to first voltage signal and is supplied to output circuit, overcurrent protection portion, the current signal that power supply main part generates is converted into indicate the second voltage signal of the size of current signal, and when detecting that the value of second voltage signal is greater than or equal to threshold value, execute overcurrent protection action, protection level switching part, in a period of the value of first voltage signal increases to steady-state value from zero, set the protection level in overcurrent protection portion to the first order, when the value of first voltage signal reaches steady-state value, set the protection level in overcurrent protection portion to the second level.
Description
Technical field
The present invention relates to power circuit fields, being suitable for the switch with bigger capacitive load more particularly to a kind of
Power supply.
Background technology
Currently, in order to ensure the safety of supply network and electrical equipment, all generally it was equipped in the design of various circuits
Overcurrent protection module.The principle of overcurrent protection module is current signal to be converted to voltage signal, then compare the voltage signal
Size with defined voltage threshold is to determine whether to execute protection act.
But in some cases, the load of Switching Power Supply is the component that capacitor etc. has very big static capacity, when
When Switching Power Supply starts, the moment that these capacitors are connected in power supply charges rapidly, just will produce much larger than stable state input current
Surge current flow into power-supply device.At this point, even if the surge current duration it is very short, be also not enough to damage Switching Power Supply and
Other components in circuit do not interfere with circuit safety, but overcurrent protection module can still be converted according to the surge current
At larger voltage signal, mistakenly execute overcurrent protection action, cause Switching Power Supply not start normally.So
In this case, it is typically only capable to the Switching Power Supply for selecting output power to be more than the required specification of actual load circuit, is caused
Unnecessary waste, improves product cost.
Invention content
The present invention is Given this, it is therefore intended that, a kind of rank that can switch overcurrent protection action on startup is provided
Switching Power Supply is suitable for having bigger capacitive load so that can be according to the power consumption phase of output power and load circuit
The principle matched selects suitable Switching Power Supply.
Switching Power Supply according to embodiment of the present invention, including：Power supply main part carries out rectification to industrial power
It is filtered to obtain first voltage signal, transformation processing is carried out to first voltage signal and supplies to output circuit, over current protection
The current signal that power supply main part generates is converted into indicate the second voltage signal of the size of current signal by shield portion, and
When detecting that the value of second voltage signal is greater than or equal to threshold value, executes overcurrent protection and act, protection level switching part,
The protection level in overcurrent protection portion is set as first by the value of first voltage signal from a period of zero increases to steady-state value
Grade, when the value of first voltage signal reaches steady-state value, sets the protection level in overcurrent protection portion to the second level.
Switching Power Supply according to embodiment of the present invention, power supply main part include：Rectification filtering unit, to industry
Power supply carries out rectifying and wave-filtering processing, transformer, and transformation processing is carried out to rectifying and wave-filtering treated voltage, first switching element,
It connects with the primary coil of transformer again in parallel with rectification filtering unit together.
Switching Power Supply according to embodiment of the present invention, overcurrent protection portion include：Control unit is one another in series
Protective resistance and detection resistance made by making the current signal from power supply main part flow through protective resistance and detection resistance
It obtains and generates second voltage signal at the both ends of detection resistance, control unit obtains second voltage signal, when second voltage signal
When value is greater than or equal to threshold value, control unit is judged as occurring overcurrent in power supply main part, executes overcurrent protection action.
Switching Power Supply according to embodiment of the present invention increases to steady-state value in the value of first voltage signal from zero
During, the value of second voltage signal is adjusted to the first detection voltage value by protection level switching part, by overcurrent protection portion
Protection level be set as the first order；When the value of first voltage signal reaches steady-state value, protection level switching part is electric by second
The value of pressure signal is adjusted to the second detection voltage value, sets the protection level in overcurrent protection portion to the second level.
Switching Power Supply according to embodiment of the present invention, protection level switching part include the first regulation and control unit and the
Two regulation and control units, the first regulation and control unit is according to the control signal from the second regulation and control unit, by second voltage Signal Regulation
Value is the first detection voltage value or the second detection voltage value, and control signal is the second regulation and control unit by first voltage Signal Regulation
It generates.
Switching Power Supply according to embodiment of the present invention, the first regulation and control unit includes the second switch being one another in series
Element, the first regulating resistor, concatenated second switch element, the first regulating resistor are connected in parallel with detection resistance together, and second
Switch element has the first control terminal for receiving the control signal from the second regulation and control unit, and second switch element, which is based on control, to be believed
Number and turn on and off；When second switch element switches so that the first regulating resistor is in parallel with detection resistance, second voltage letter
Number value be adjusted to the first detection voltage value；When second switch element OFF so that the first regulating resistor disconnects, by
The value of two voltage signals is adjusted to the second detection voltage value.
Switching Power Supply according to embodiment of the present invention, the second regulation and control unit includes third switch element, second
Regulating resistor, divider resistance, control resistance, one end of divider resistance and the output end of the first voltage signal of power supply main part connect
It connects, the other end is connect with first control terminal of one end of control resistance and second switch element, controls another termination of resistance
Ground, together with control resistor coupled in parallel, third switch element, which has, to be received for the third switch element being one another in series, the second regulating resistor
Second control terminal of the first voltage signal from power supply main part, third switch element connected based on first voltage signal or
Shutdown；Third switch element turns off in a period of the value of first voltage signal increases to steady-state value from zero so that the second pressure regulation
Resistance disconnects, second switch element switches；The third switching elements ON when the value of first voltage signal reaches steady-state value,
So that the second regulating resistor and control resistor coupled in parallel, second switch element OFF.
Switching Power Supply according to embodiment of the present invention, second, third switch element are triodes, first,
Two control terminals are the base stages of triode.
Switching Power Supply according to embodiment of the present invention, threshold value are constants.
Switching Power Supply according to embodiment of the present invention, the second control terminal come from via a voltage stabilizing element reception
The conduction threshold of the first voltage signal of power supply main part, voltage stabilizing element is less than steady-state value.
According to the Switching Power Supply of the rank provided by the invention that can switch overcurrent protection action on startup, then may be used
With suitable for the Switching Power Supply with bigger capacitive load so that can be according to the power consumption phase of output power and load circuit
Matched principle selects suitable Switching Power Supply, reduces power supply cost.
Description of the drawings
Fig. 1 is the schematic diagram of the function module for the Switching Power Supply for showing an embodiment of the invention.
Fig. 2 is the figure of the circuit structure for the Switching Power Supply for showing an embodiment of the invention.
Fig. 3 is the first, second voltage signal and second, third switch member for showing an embodiment of the invention
The schematic diagram of the voltage value and the relationship of time of first, second control terminal of part.
Wherein, the reference numerals are as follows：
100 Switching Power Supplies
110 power supply main parts
111 rectification filtering powers
120 overcurrent protection portions
121 control units
130 protection level switching parts
131 first regulation and control units
132 second regulation and control units
140 output circuits
T1 transformers
The test sides IS
V1First voltage signal
V2Second voltage signal
VthThreshold value
VinIndustrial power
IdCurrent signal
DA1 rectifier bridges
C1 filter capacitors
Q1 first switching elements
Q10 second switch elements
The first control terminals of S1
Q11 third switch elements
The second control terminals of S2
R10 protective resistances
R11 detection resistances
The first regulating resistors of R12
R15 divider resistances
R16 controls resistance
The second regulating resistors of R17
DZ01 zener diodes
Ctrl controls signal
VWSteady-state value
VDZThe conduction threshold of zener diode
VS1、VS2The voltage value of first, second control terminal
VQThe connection voltage of second, third switch element
Specific implementation mode
Hereinafter, being explained with reference to the Switching Power Supply of the present invention.
As shown in Figure 1, the Switching Power Supply 100 of an embodiment of the invention at least has：Power supply main part 110, mistake
Current protection portion 120 and protection level switching part 130.Wherein, power supply main part 110 carries out industrial power at rectifying and wave-filtering
Reason obtains first voltage signal V1, and to first voltage signal V1It carries out transformation to handle to obtain output voltage, which supplies
To output circuit.The current signal I that overcurrent protection portion 120 generates power supply main part 110dIt is converted into indicate described
The second voltage signal V of the size of current signal2, and work as and detect second voltage signal V2More than or equal to threshold value VthWhen, it holds
Row overcurrent protection acts.Protection level switching part 130 is in first voltage signal V1Value increase to steady-state value V from zeroWDuring
It is interior, the protection level in overcurrent protection portion 120 is set to the first order, as the first voltage signal V1Value reach the stable state
Value VWWhen, set the protection level in overcurrent protection portion 120 to the second level.In this way, protection level switching part 130 can be passed through
To second voltage signal V2Value adjusting, play the switching of the protection level to the action of the overcurrent protection of Switching Power Supply 100
Effect.
As shown in Fig. 2, specifically, power supply main part 110 includes：Industrial power Vin, rectification filtering unit 111, transformer
T1, first switching element Q1.Industrial power VinIt is AC power.Rectification filtering unit 111 includes and industrial AC power VinAnd
The rectifier bridge DA1 and filter capacitor C1 of connection, to industrial AC power VinRectifying and wave-filtering processing is carried out, is obtained with this smooth straight
The first voltage signal V of stream1.In other implementations, rectification filtering unit 111 may be designed in other with rectification
The circuit of filter function, as long as ensureing the first voltage signal V of output1It is smooth d. c. voltage signal.In this implementation
In mode, first voltage signal V1It increases sharply when Switching Power Supply starts, reaches defined steady-state value VWStablize constant put down afterwards
Sliding direct current signal.The primary coil for the transformer T1 being one another in series is connected in parallel on filter capacitor C1's together with first switching element Q1
Both ends make the first voltage signal V handled by rectifying and wave-filtering by controlling the on or off of first switching element Q11Institute
It states and induces output voltage signal on the secondary coil of transformer.The output voltage signal is for supplying output circuit 140.At this
In embodiment, first switching element Q1 selects field-effect transistor (FET), such as junction field effect transistor (JFET) or absolutely
Edge grid-type field-effect transistor (also known as MOS transistor), in other implementations, first switching element Q1 can also be selected
Other switch elements, such as double pole triode.In addition, in the present embodiment, in the primary coil of transformer T1 and
In the series arm of one switch element Q1, also there are one resistance R1 for series connection, can play certain metering function, prevent first to open
Element Q1 damages are closed, in other implementations, can also be omitted, or be set as other current-limiting protection elements.
As shown in Fig. 2, in an embodiment of the invention, overcurrent protection portion 120 includes at least：Control unit
121, protective resistance R10, detection resistance R11.The one end protective resistance R10 and the first switching element Q1 in power supply main part 110
One end connection not connect with transformer, the other end are connected with one end of detection resistance 11, and detection resistance R11
The other end is grounded.In this way, the current signal I that power supply main part 110 is exporteddIt is converted into second electricity at the both ends detection resistance R11
Press signal V2.In this way, the second voltage signal V that overcurrent protection portion 120 passes through the both ends detection detection resistance R112, just
The current signal I generated in power supply main part 110 can be gone out with indirect detectiondThe case where, it, can be in the case where there is overcurrent
Overcurrent protection action is executed in time, protects the circuit components in Switching Power Supply 100.In other implementations, also may be used
To omit R10, R11, and connected R1 as R11 into overcurrent protection portion 120, the holdings such as other components and its connection relation
It is constant.In this way, it can also realize the excess current protective function in overcurrent protection portion 120, and save component, simplify
Circuit, it is cost-effective.As long as the current signal I in power supply main part 110 can will be indicateddVoltage or current signal
Supply can also use other modes to overcurrent protection portion 120.
Specifically, in the present embodiment, control unit 121 at least has detection second voltage signal V2Test side
IS, when test side, IS detects second voltage signal V2Value be greater than or equal to threshold value VthWhen, it is judged as in power supply main part 110
There is overcurrent, to execute overcurrent protection action.In the present embodiment, control unit 121 is by with overcurrent protection
The IC10 (IC10 uses the general power supply with overcurrent detection to control IC) of function is constituted, in other embodiments
In, control unit 121 can also be made of other devices with the following functions：Second detected by comparing test side IS
Voltage signal V2Value and threshold value VthSize, to judge whether to occur overcurrent, and it is dynamic correspondingly to execute overcurrent protection
Make.
Further, here, threshold value VthIt is constant, according to the device of different composition control units 121, threshold value Vth?
It is different；But for same control unit 121, threshold value VthValue be changeless determining value.It is existing that there is overcurrent
The IC chip of defencive function does not have the function that can switch different overcurrent protection ranks according to actual conditions.If again
Exploitation designs a kind of device that can switch different overcurrent protection ranks according to actual conditions, then R&D costs are very high, grind
The hair period is also very long, and feasibility is low.And according to the present embodiment, only it need to select the existing IC cores with excess current protective function
Piece, and the second voltage detected by adjusting test side IS is designed using elements such as common switch element, resistance, capacitances
Signal V2Value mode, to switch the circuit module of different overcurrent protection ranks.Embodiments of the present invention can letter
Folk prescription achievees the effect that the protection level for switching overcurrent protection portion 120 just, at low cost.
In addition, in the present embodiment, capacitance C10 is also associated on the test side IS of control unit 121, capacitance C10's
The other end is grounded.
For example, protection level switching part 130 is in first voltage signal V1Value increase to steady-state value V from zeroWIn a period of,
By second voltage signal V2Value be adjusted to the first detection voltage value, by the execution overcurrent protection in overcurrent protection portion 120
The protection level of action is set as the first order；As first voltage signal V1Value reach steady-state value VWWhen, by second voltage signal
V2Value be adjusted to the second detection voltage value, the protection level that the execution overcurrent protection in overcurrent protection portion 120 is acted
It is set as the second level.In this way, before and after Switching Power Supply 100 starts, protection level switching part 130 can be according to first voltage
Signal V1Different situations, to second voltage signal V2Different adjustment is done, and then reaches switching overcurrent protection portion 120
Execute the effect of the protection level of overcurrent protection action.
Preferably, in the present embodiment, the first detection voltage value, which is protection level switching part 130, makes at that time corresponding
Second voltage signal V2Value size suitably reduce obtained from, and second detection voltage value be then protection level switching part
130 make corresponding second voltage signal V at that time2Value maintain it is substantially constant obtained from.When Switching Power Supply 100 starts,
I.e. in first voltage signal V1Value increase to steady-state value V from zeroWIt is very short in a period of, although in 110 moment of power supply main part
Generate prodigious surge current, the current signal I of outputdValue it is very big, current signal IdThe both ends detection resistance R11 being converted into
Second voltage signal V2Value also become very big.But protection level switching part 130 makes second voltage signal V at this time2Value
Size is suitably reduced to the first detection voltage value.Voltage value is detected by suitably reduce this first in overcurrent protection portion 120
With fixed threshold value VthIt makes comparisons, to judge whether overcurrent occur in power supply main part 110, if need to execute over current protection
Shield acts.Obviously, in this way in the case where Switching Power Supply 100 is in rigid starting state, just it is not easy because starting moment second
Voltage signal V2Value it is very big, and cause overcurrent protection portion 120 mistakenly execute overcurrent protection action, so that it is guaranteed that switch
Power supply 100 uninterruptedly can normally start.With the overcurrent protection rank of the Switching Power Supply 100 under starting state for first
Grade, Switching Power Supply 100 on the whole improves " degrees of tolerance " of overcurrent at this time, has reached " the overcurrent being equivalent on the whole
Rotection thresholds VthThe effect of raising ".Terminate when the startup stage of Switching Power Supply 100, i.e., as first voltage signal V1Value reach
Above-mentioned steady-state value VWWhen, the circuit of entire Switching Power Supply is operated in normal steady state, and protection level switching part 130 makes second voltage
Signal V2The size of value substantially remain stationary constant, i.e., do not change the second voltage that Switching Power Supply 100 is under normal steady state
Signal V2Value, second voltage signal V herein2The value of script is the second detection voltage value.Overcurrent protection portion 120 pass through by
Second voltage signal V under the normal steady state2Value and fixed threshold value VthIt makes comparisons, to judge to be in power supply main part 110
It is no overcurrent occur, if to need to execute overcurrent protection action.Obviously, 100 normal work of Switching Power Supply has been switched in this way
Overcurrent protection rank in the case of work, using the overcurrent protection rank of the Switching Power Supply 100 of normal operating conditions as the second level,
Switching Power Supply 100 is reduced to normal condition to " degrees of tolerance " of overcurrent on the whole at this time.In this way, just making the switch electricity of reduction
The overcurrent protection rank of source 100 on the whole improves again, is equivalent to " whole overcurrent protection threshold value VthIt is reduced to again normal
It is horizontal ".Certainly, in other implementations, different definition modes can also be used to the rank of overcurrent protection, also may be used
Three or more overcurrent protection ranks to be arranged in a similar manner, can also between different ranks switching mode,
Sequence redefines.
Further, in the present embodiment, protection level switching part 130 includes at least：First regulation and control unit 131 and the
Two regulation and control units 132.Wherein, the first regulation and control unit 131 receives the control of the second regulation and control unit 132, is adjusted further according to from second
The control signal Ctr for controlling unit 132, to adjust second voltage signal V2Obtain the first detection voltage value or the second detection voltage
Value.Control signal Ctr is the second regulation and control unit 132 by adjusting first voltage signal V1It generates.In other embodiment party
In formula, protection level switching part 130 can also include three or more regulation and control units, make overcurrent protection portion 120 to realize
The effect switched between three or more protection levels.
Specifically, in the present embodiment first regulation and control unit include at least be one another in series second switch element Q10,
First regulating resistor R12.Wherein, concatenated second switch element Q10, the first regulating resistor R12 together with overcurrent protection portion
Detection resistance 11 in 120 is in parallel.Second switch element Q10 has the first control terminal S1.Second switch element Q10 is based on the
One control terminal S1 receive from second regulation and control unit 132 control signal Ctr and be turned on or off.When control signal
When the value of Ctrl is sufficient to make second switch element switches, the first regulating resistor R12 and detection resistance R11 is connected in parallel, at this time
Second voltage signal V2Value be adjusted to the first detection voltage value.The first detection voltage value is equivalent to the first regulating resistor
The voltage value at the parallel circuit both ends of R12 and detection resistance R11.When control signal Ctrl is insufficient for second switch element
Q10 is connected, and when second switch element Q10 is turned off, the first regulating resistor R12 is disconnected, i.e., protection level switching part 130 is not right
Second voltage signal V2It is adjusted, at this point, second voltage signal V2Script of keeping intact value (both ends detection resistance R11
Voltage value) it is the second detection voltage value.Obviously, the first regulating resistor R12 and detection resistance R11 is connected in parallel the whole of circuit
Bulk resistor certainly less than the first individual resistance of regulating resistor R12 detection resistances R11, therefore for power supply main part 110 generate
The voltage value at the parallel circuit entirety both ends of the current signal Id, the first regulating resistor R12 and detection resistance R11 of same size
Less than the voltage value at the independent both ends detection resistance R11.Therefore, when the first regulation and control unit 131 of protection level switching part 130 passes through
The second voltage signal V for detecting overcurrent protection portion 120 may be implemented in the on or off of second switch element Q102Value tune
Section is substantially constant for the first detection voltage value reduced or the normal second detection voltage value of maintenance.It thereby realizes to mistake
The switching control of the protection level in current protection portion 120.
Specifically, the second regulation and control unit 132 in the present embodiment includes at least third switch element Q11, the second tune
Piezoresistance R17, divider resistance R15, control resistance R16.Wherein, one end of divider resistance R15 and the first of power supply main part 110
Voltage signal V1Output end connection, the other end and second opening in one end and overcurrent protection portion 120 for controlling resistance R16
Close the first control terminal S1 connections of element Q10；And control the other end ground connection of resistance R16.The third switch being serially connected
Element Q11, the second regulating resistor R17 are in parallel with control resistance R16 together.Third switch element Q11 has the second control terminal
S2.The first voltage signal V from power supply main part 110 that third switch element Q11 is received based on second control terminal S21
And it turns on and off.
In addition, in the present embodiment, further including in the second regulation and control unit 132：The zener diode being one another in series
DZ01 and resistance R20, resistance R21.Wherein, the first voltage signal of the cathode of zener diode DZ01 and power supply main part 110
V1Output end connection, anode connect with one end of resistance R20；The other end of resistance 20 and one end of resistance R21 and third
The second control terminal S1 connections of switch element Q11；And the other end ground connection of resistance R21.That is, the second control terminal S1 receive be
First voltage signal V from power supply main part 1101Fall the voltage signal at the both ends of resistance R21.Preferably, two pole of voltage stabilizing
The conduction threshold V of pipe DZ01DZLess than above-mentioned steady-state value VW。
In first voltage signal V1Value increase to above-mentioned steady-state value V from zeroWIn a period of, in first voltage signal V1
Value reach the conduction threshold of zener diode DZ01 before, zener diode DZ01 is off state.That is, no matter power supply main body
The current signal I generated in portion 110dValue size be it is how many, no matter first voltage signal V1Value how to change, first electricity
Press signal V1Voltage value all almost all fall at the both ends of zener diode DZ01, and the voltage at the both ends resistance R20, R21
Value is all almost nil.The first voltage signal V that second control terminal S2 is received1Fall the voltage signal values at the both ends of resistance R21
Size be insufficient to allow third switch element Q11 to connect, therefore third switch element Q11 is constantly in off state, so that the
Two regulating resistor R17 are disconnected.At this point, the control signal Ctr that the first control terminal S1 of second switch element Q10 is received
Value is first voltage signal V1The voltage value at the both ends of control resistance R16 is fallen, and the voltage value is sufficient to make second switch
Element Q10 is connected.As first voltage signal V1Value reach steady-state value VWWhen, due to steady-state value VWMore than the zener diode
The conduction threshold of DZ01, so zener diode DZ01 becomes conducting state.That is the voltage value at the both ends zener diode DZ01 is several
Stabilization is held permanently at conduction threshold VDZ.At this point, the first voltage signal V that the second control terminal S2 is received1In resistance R21
Both ends caused by voltage drop size | V1-VDZ-V20| it is sufficient to make third switch element Q11 to connect (V20It is first voltage letter
Number V1The voltage drop caused by the both ends resistance R20).At this point, the second regulating resistor R17 is connected in parallel with control resistance R16, first
The value for the control signal Ctr that control terminal S1 is received is first voltage signal V1It falls in the second regulating resistor R17, control resistance
The voltage value at the both ends of the parallel circuit entirety of R16.Obviously, individually the resistance of control resistance R16 is naturally larger than the second pressure regulation
The overall electrical resistance of the parallel circuit of resistance R17, control resistance R16, in first voltage signal V1All it is same steady-state value VWFeelings
Under condition, falls the global voltage value at the former both ends and be naturally larger than the global voltage value fallen at the latter both ends.Therefore believe in first voltage
Number V1Reach steady-state value VWCritical point on, third switch element Q11 from shutdown become connect before and after, second switch element Q10
The voltage values that receive of the first control terminal S1 reduce quickly, to make second switch element Q10 turn off.In this way,
The first voltage signal V that two regulation and control units are generated based on power supply main part 1101, to generate different control signal Ctrl, and lead to
The different control signal Ctrl is crossed to control the second regulation and control unit switch operating state, is finally reached and adjusts overcurrent protection portion
120 working condition switches the effect of the overcurrent protection rank of entire Switching Power Supply 100.
Preferably, as shown in Fig. 2, the second regulation and control unit can further include：Capacitance C11, capacitance C12, resistance
R13, resistance R14, resistance R18, resistance R19, diode D10, diode D11.Wherein, one end of capacitance C11 and the first control
Hold S1 connections, other end ground connection；One end of resistance R13 is connect with the first control terminal S1, other end ground connection；One end of resistance R14
It is connect with the first control terminal S1, the other end is connect with the cathode of diode D10；And the anode of diode D10 and control resistance R16
Ungrounded end connection；One end of capacitance C12 is connect with the second control terminal S2, other end ground connection；One end of resistance R18 and second
Control terminal S2 connections, other end ground connection；One end of resistance R19 is connect with the second control terminal S2, the moon of the other end and diode D11
Pole connects；And the anode of diode D11 is connect with the ungrounded end of resistance R21.These above-mentioned capacitances, resistance and diode member
Part helps out in circuit, in this way, can ensure the feelings that entire protection level switching part 130 is basically unchanged in function
Under condition, circuit can more reliablely and stablely work, and preferably play the work(for the protection level for adjusting overcurrent protection portion 120
Energy.
Further, in the present embodiment, second, third switch element Q10, Q11 selects the identical triode of specification,
And then the first, second control terminal S1, S2 is the base stage of triode；In other implementations, second, third switch element
The triode that Q10, Q11 can also select specification different respectively, or select other with the switch element of on or off effect,
Such as junction field effect transistor (JFET) or insulated-gate type field effect transistor (also known as MOS transistor) etc. are selected, relatively
Ying Di, the first, second control terminal S1, S2 at this time are the grids of field-effect transistor.
In addition, in the present embodiment, corresponding resistance R13 and resistance R18, resistance R14 and resistance R19, capacitance C11 and
Capacitance C12, diode D10 and diode D11 also select the element of same size.In other implementations, can also
Resistance, capacitance and the diode of different size are selected respectively.
As shown in figure 3, in the present embodiment, since second, third switch element Q10, Q11 select specification identical three
Pole pipe, and the specification of corresponding resistance R14 and resistance R19, capacitance C11 and capacitance C12 are all identical, therefore when being applied to corresponding the
Two, the voltage in base stage S1, S2 of third switch element Q10, Q11 all reaches identical and is higher than second, third switch element
The connection voltage V of Q10, Q11QSome value when, the turn-on delay time of second, third switch element Q10, Q11 are equal；When
The voltage being applied in corresponding base stage S1, S2 all reaches the identical conducting voltage V less than triodeQSome value when,
The turn-off delay time of second, third switch element Q10, Q11 are equal.It, will as t=0 at the time of startup using Switching Power Supply 100
The voltage of the first control terminal S1 of second switch element Q 10 is set as VS1, the electricity of the second control terminal S2 of third switch element Q11
Pressure is set as VS2, second switch element Q10 is set as t at the time of connection1, zener diode DZ01 conducting at the time of is set as t2,
Third switch element Q11 is set as t at the time of connection3, second switch element Q10 is set as t at the time of being turned off4, first voltage
Signal V1Value reach steady-state value VWAt the time of be set as t5.Fig. 3 shows that protection level switching part 130 switches overcurrent protection
During the protection level in portion, the first, second voltage signal V1、V2And first, second control terminal S1, S2 voltage value at any time
Between variation relation schematic diagram.
In addition, in the present embodiment, with base stage (control terminal) S1 of second switch element Q10 resistance R14 connecting and
Capacitance C11 constitutes delay circuit, can be according to following formula
t1=R14C11 (formula 1)
Resistance R14 and capacitance C11 are configured according to needing, to determine to start to second switch member from Switching Power Supply 100
Time t needed for the connection of part Q101.Similarly, the resistance R19 being connect with the base stage of third switch element Q11 (control terminal) S2
Delay circuit is constituted with capacitance C12, it can be according to following formula
t3=R19C12 (formula 2)
Resistance R19 and capacitance C12 are configured according to needing, to determine to start to third switch member from Switching Power Supply 100
Time t needed for the connection of part Q113.In addition, on this basis, by adjusting it is above-mentioned help out in circuit it is each
A resistive element, capacity cell, diode, zener diode etc. can to start to zener diode from Switching Power Supply 100
Time t needed for DZ01 conductings2Required time t is connected more than second switch element Q101, and make second switch element
T at the time of Q10 is turned off4It can be substantially equal to as first voltage signal V1Value reach steady-state value VWAt the time of t5.In this way, just
Meet the effect for the protection level that switching overcurrent protection portion 120 is played to make protection level switching part 130 work normally
Timing requirements.In other implementations, other modes can also be taken, protection level switching part 130 is made to switch
During the protection level in current protection portion, the first, second voltage signal V1、V2And first, second control terminal S1, S2 electricity
The pressure value relationship of changing with time meets other rational sequential relationships.
In addition, in the present embodiment, in order to enable second switch element Q10 can realize expection on or off and normally
Function, can be according to the industrial power V selected by power supply main part 110inVoltage value size, to configure divider resistance
The resistance value of R15, control resistance R16.Similarly, in order to enable third switch element Q11 can be realized on or off and normally
Expected function, can be according to the size of the voltage value of the industrial power Vin selected by power supply main part 110, to configure voltage stabilizing
Specification (such as conduction threshold V of diode DZ01DZDeng) and resistance R20, resistance R21 resistance value.
Under the different application scenarios of Switching Power Supply 100, the specification of above-mentioned each component can be fitted according to situation
Work as adjustment, to meet the requirements.
The present invention is not limited to above-mentioned each embodiment, but can be into the range represented by claim
The various changes of row, embodiment also includes obtained from being appropriately combined the technological means that different embodiments discloses respectively
In the range of technical scheme of the present invention.
Claims (9)
1. a kind of Switching Power Supply, which is characterized in that including：
Power supply main part carries out rectifying and wave-filtering to industrial power and handles to obtain first voltage signal, to the first voltage signal
It carries out transformation processing and supplies to output circuit,
Overcurrent protection portion is converted into the current signal that the power supply main part generates that can indicate the big of the current signal
Small second voltage signal, and when detecting that the value of the second voltage signal is greater than or equal to threshold value, execute over current protection
Shield acts,
Protection level switching part will be described excessively electric in a period of the value of the first voltage signal increases to steady-state value from zero
The protection level of stream protection portion is set as the first order, will be described when the value of the first voltage signal reaches the steady-state value
The protection level in overcurrent protection portion is set as the second level；
The protection level switching part includes that the first regulation and control unit and second regulate and control unit,
It is described first regulation and control unit include second switch element, it is described first regulation and control unit by the second switch element according to
From it is described second regulation and control unit control signal and turn on and off, the value of the second voltage signal is adjusted to first
Voltage value or the second detection voltage value are detected,
The second regulation and control unit includes third switch element, and the second regulation and control unit is based on by the third switch element
The first voltage signal and turn on and off, to generate the control signal.
2. Switching Power Supply as described in claim 1, which is characterized in that the power supply main part includes：
Rectification filtering unit carries out the rectifying and wave-filtering processing to industrial power,
Transformer carries out the transformation processing to the voltage of the rectifying and wave-filtering treated industrial power,
First switching element is connected again in parallel with the rectification filtering unit together with the primary coil of the transformer.
3. Switching Power Supply as described in claim 1, which is characterized in that
The overcurrent protection portion includes：Control unit, the protective resistance being one another in series and detection resistance,
By making the current signal from the power supply main part flow through the protective resistance and the detection resistance so that in institute
The both ends for stating detection resistance generate the second voltage signal,
Described control unit obtains the second voltage signal, when the value of the second voltage signal is greater than or equal to threshold value,
Described control unit is judged as occurring overcurrent in the power supply main part, executes overcurrent protection action.
4. Switching Power Supply according to any one of claims 1 to 3, which is characterized in that
During the value of the first voltage signal increases to steady-state value from zero, the protection level switching part is by described second
The value of voltage signal is adjusted to the first detection voltage value, sets the protection level in the overcurrent protection portion to the first order；
When the value of the first voltage signal reaches the steady-state value, the protection level switching part is by the second voltage signal
Value is adjusted to the second detection voltage value, sets the protection level in the overcurrent protection portion to the second level.
5. Switching Power Supply as claimed in claim 3, which is characterized in that
It is described first regulation and control unit further include with concatenated first regulating resistor of second switch element,
The concatenated second switch element, first regulating resistor are connected in parallel with the detection resistance together,
The second switch element has the first control terminal for receiving the control signal from the second regulation and control unit, when
When the second switch element switches so that first regulating resistor is in parallel with the detection resistance, the second voltage letter
Number value be adjusted to it is described first detection voltage value；When the second switch element OFF so that first regulating resistor
It disconnects, the value of the second voltage signal is adjusted to the second detection voltage value.
6. Switching Power Supply as described in claim 1, which is characterized in that
The second regulation and control unit further includes the second regulating resistor, divider resistance, controls resistance,
One end of the divider resistance is connect with the output end of the first voltage signal of the power supply main part, the other end with
One end of the control resistance and first control terminal connection of the second switch element, it is described to control the another of resistance
End ground connection, the third switch element that is one another in series, second regulating resistor together with the control resistor coupled in parallel,
The third switch element has the second control terminal for receiving the first voltage signal from the power supply main part,
The third switch element shutdown in a period of value of the first voltage signal increases to the steady-state value from zero so that institute
It states the second regulating resistor to disconnect, the second switch element switches；When the value of the first voltage signal reaches described steady
Third switching elements ON when state value so that second regulating resistor and the control resistor coupled in parallel, described second opens
Close element OFF.
7. the Switching Power Supply as described in claim 5 or 6, which is characterized in that
Second, third described switch element is triode, and first, second control terminal is the base stage of triode.
8. Switching Power Supply as claimed in claim 4, which is characterized in that
The threshold value is constant.
9. Switching Power Supply as claimed in claim 6, which is characterized in that
Second control terminal receives the first voltage signal from the power supply main part, institute via a voltage stabilizing element
The conduction threshold for stating voltage stabilizing element is less than the steady-state value.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510367472.5A CN106329483B (en) | 2015-06-29 | 2015-06-29 | Switching Power Supply |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510367472.5A CN106329483B (en) | 2015-06-29 | 2015-06-29 | Switching Power Supply |
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| CN106329483A CN106329483A (en) | 2017-01-11 |
| CN106329483B true CN106329483B (en) | 2018-11-09 |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009153364A (en) * | 2007-11-28 | 2009-07-09 | Fuji Electric Device Technology Co Ltd | Switching power supply device |
| CN102290995A (en) * | 2011-07-16 | 2011-12-21 | 西安电子科技大学 | Rectifier diode temperature compensation circuit in flyback converter |
| CN203026904U (en) * | 2012-12-14 | 2013-06-26 | Tcl空调器(中山)有限公司 | Over-current protection circuit and PFC (power factor correction) control circuit with same |
| CN103475191A (en) * | 2013-09-10 | 2013-12-25 | 上海斐讯数据通信技术有限公司 | Control circuit of switching power supply |
| CN104104063A (en) * | 2014-07-28 | 2014-10-15 | 鹰星精密工业（深圳）有限公司 | Flyback converter overcurrent protection achieving method for nonlinear circuit |
-
2015
- 2015-06-29 CN CN201510367472.5A patent/CN106329483B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009153364A (en) * | 2007-11-28 | 2009-07-09 | Fuji Electric Device Technology Co Ltd | Switching power supply device |
| CN102290995A (en) * | 2011-07-16 | 2011-12-21 | 西安电子科技大学 | Rectifier diode temperature compensation circuit in flyback converter |
| CN203026904U (en) * | 2012-12-14 | 2013-06-26 | Tcl空调器(中山)有限公司 | Over-current protection circuit and PFC (power factor correction) control circuit with same |
| CN103475191A (en) * | 2013-09-10 | 2013-12-25 | 上海斐讯数据通信技术有限公司 | Control circuit of switching power supply |
| CN104104063A (en) * | 2014-07-28 | 2014-10-15 | 鹰星精密工业（深圳）有限公司 | Flyback converter overcurrent protection achieving method for nonlinear circuit |
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|---|---|
| CN106329483A (en) | 2017-01-11 |
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