CN106385186A - Constant-voltage constant-current switching power source - Google Patents
Constant-voltage constant-current switching power source Download PDFInfo
- Publication number
- CN106385186A CN106385186A CN201610848251.4A CN201610848251A CN106385186A CN 106385186 A CN106385186 A CN 106385186A CN 201610848251 A CN201610848251 A CN 201610848251A CN 106385186 A CN106385186 A CN 106385186A
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- Prior art keywords
- power supply
- voltage
- constant
- constant pressure
- switch
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Classifications
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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
- H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
- H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
- H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
- H02M7/12—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M7/21—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M7/217—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M7/219—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only in a bridge configuration
-
- 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
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
- H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
- H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
- H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
- H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/33569—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements
Abstract
The invention discloses a constant-voltage constant-current switching power source. The constant-voltage constant-current switching power source comprises a transformer (1), a main switch tube (Q1), a constant-voltage constant-current controller (3), a power supply circuit (4), a voltage dividing circuit (5), a current detection resistor (6) and a rectifying and filtering circuit (7). When the constant-voltage constant-current switching power source of the invention is under a constant voltage working mode, the constant-voltage constant-current controller actively detects working voltage provided by the output end of the power supply circuit in each switching cycle, determines whether the power supply circuit needs to be charged according to the magnitude of the working voltage, stops power supply when the working voltage is higher than second reference voltage and restores power supply when the working voltage is lower than the second reference voltage, so that the working voltage will not change with output power, and therefore, the complicated debugging design of the power supply circuit can be avoided; and voltage requirements of the second pin end of the constant-voltage constant-current controller can be lowered, so that the constant-voltage constant-current controller can be manufactured by adopting a standard 5V CMOS process, and therefore, the production cost of the constant-voltage constant-current switching power source can be decreased.
Description
Technical field
The present invention relates to power technique fields, particularly to a kind of constant pressure and flow Switching Power Supply.
Background technology
Fig. 1 is a kind of circuit diagram of typical constant pressure and flow Switching Power Supply in prior art, in FIG, constant pressure and flow control
The electric power system of coremaking piece 700 is by the assists winding NA group of resistance 640, electric capacity 650, fly-wheel diode 600 and transformer 100
Become.Its operation principle is：When constant pressure and flow Switching Power Supply is just opened, electric capacity 650 is charged by resistance 640, now constant pressure and constant
Flow control chip 700 is in stopped status；When the operating voltage that electric capacity 650 provides rises in constant pressure and flow control chip 700
During a certain voltage that portion sets, constant pressure and flow control chip 700 is started working, and turns on NPN200, the input winding of transformer 100
NP starts to charge up, and after inputting a certain setting value of primary current arrival in winding NP, constant pressure and flow control chip 700 is closed
NPN200, in input winding NP, the energy of storage will transition to export in winding NS and assists winding NA, respectively output loading
Power with constant pressure and flow control chip 700.Constant pressure and flow control chip 700 determines to open according to output voltage situation next time
In the time of NPN200 or input winding NP, the peak value of primary current, goes round and begins again.Generally speaking constant pressure and flow control chip 700
The height of operating voltage VCC providing not according to electric capacity 650 makes corresponding adjustment, the voltage of stable rear operating voltage VCC
Value is mainly determined by output voltage Vo, output umber of turn NS1 and assists winding number of turn NA1, VCC ≈ Vo*NA1/NS1.But
Due to transformer 100 nonideality, the voltage of operating voltage VCC not only changes with the change of output voltage, also with defeated
Go out the increase of electric current and increase, reduce with the reduction of output current.This leads to the voltage of operating voltage VCC in different loads
Under be widely varied, and the operating voltage range of constant pressure and flow control chip 700 tends not to too big, and this makes this power supply circuits
Design need repeatedly to attempt adjustment to can be only achieved preferable effect.
Content of the invention
In order to solve problem of the prior art, embodiments provide a kind of constant pressure and flow Switching Power Supply.Described skill
Art scheme is as follows：
Embodiments provide a kind of constant pressure and flow Switching Power Supply, including：Transformer, main switch, constant pressure and flow
Controller, power supply circuits, bleeder circuit, current sense resistor, current rectifying and wave filtering circuit,
The positive pole of current rectifying and wave filtering circuit is connected with one end of input winding of transformer and the first end of power supply circuits respectively,
The negative pole of current rectifying and wave filtering circuit is connected with one end of current sense resistor and constant pressure and flow controller first pin respectively, power supply electricity
Road output end is connected with constant pressure and flow controller second pin, the other end of current sense resistor, the second end of power supply circuits, with
And constant pressure and flow controller the 3rd pin common ground,
The other end that transformer inputs winding is connected with the colelctor electrode of main switch, and the base stage of main switch and emitter stage divide
It is not connected with the 4th pin of constant pressure and flow controller and the 5th pin, the two ends of the assists winding of transformer are electric with partial pressure respectively
Road connects, and bleeder circuit is also connected with the 6th pin of constant pressure and flow controller,
Constant pressure and flow controller is used for according to the feedback voltage receiving on bleeder circuit and default first reference voltage
Between relation, control constant pressure and flow Switching Power Supply be operated pattern switching, described mode of operation includes：Constant voltage mode of operation
Or constant current mode；
Constant pressure and flow controller is additionally operable to the operating voltage providing according to power supply circuits output end and default second reference
Relation between voltage, to judge power supply circuits the need of being charged.
In the above-mentioned constant pressure and flow Switching Power Supply of the embodiment of the present invention, described constant pressure and flow controller includes：First ratio
Compared with device, the second comparator, the 3rd comparator, the 4th comparator, logic circuit, drive circuit, current source, first switch, second
Switch, the 3rd switch, the 4th switch,
The negative-phase input of first comparator is connected with bleeder circuit, and its normal phase input end accesses default first with reference to electricity
Pressure, its output end is connected with logic circuit, when the feedback voltage that first comparator receives is less than the first reference voltage, logic
The first level signal that circuit exports according to first comparator, controls constant pressure and flow Switching Power Supply to enter constant current mode, when
The feedback voltage that first comparator receives be more than the first reference voltage when, logic circuit exported according to first comparator first
Level signal, controls constant pressure and flow Switching Power Supply to enter constant voltage mode of operation；
The normal phase input end of the second comparator is connected with the output end of power supply circuits, and its negative-phase input accesses default the
Two reference voltages, its output end is connected with logic circuit, and logic circuit enters constant voltage mode of operation in constant pressure and flow Switching Power Supply
When, judge power supply circuits the need of being charged according to the second electrical level signal of the second comparator output；
The normal phase input end of the 3rd comparator is connected with one end of current sense resistor, and its negative-phase input accesses default
3rd reference voltage, its output end is connected with logic circuit, and logic circuit enters constant voltage Working mould in constant pressure and flow Switching Power Supply
During formula, judge whether to open the charging to power supply circuits according to the three level signal of the 3rd comparator output；
The normal phase input end of the 4th comparator is connected with one end of current sense resistor, and its negative-phase input accesses default
4th reference voltage, its output end is connected with logic circuit, and logic circuit enters constant voltage Working mould in constant pressure and flow Switching Power Supply
The maximum in power supply circuits charging interval, the 4th reference during formula, is limited according to the 4th level signal of the 4th comparator output
Voltage is less than the 3rd reference voltage；
The also fixing output recurrent pulses control signal of logic circuit, to control the conducting of first switch, drive circuit divides
It is not connected with first switch, second switch, the 3rd switch, the control end of the 4th switch and logic circuit, for according to logic
The control signal of circuit output, controls first switch, second switch, the 3rd switch, the working condition of the 4th switch；
One end of first switch be connected with power supply circuits output end by current source and its other end respectively with second switch
One end and the base stage of main switch connect, the other end of second switch ground connection, one end of the 3rd switch and power supply circuits export
End connects and its other end is connected with one end of the 4th switch, and the other end of the 4th switch is with the other end of current sense resistor altogether
With ground connection.
In the above-mentioned constant pressure and flow Switching Power Supply of the embodiment of the present invention, described bleeder circuit includes：First resistor and
Two resistance, one end of first resistor is connected with one end of the assists winding of transformer, and the other end of first resistor is respectively with second
One end of resistance and the 6th pin connection, the other end of second resistance and the assists winding of transformer of constant pressure and flow controller
Other end common ground.
In the above-mentioned constant pressure and flow Switching Power Supply of the embodiment of the present invention, the 4th reference voltage and the 3rd reference voltage are
Negative voltage, and the absolute value of the 3rd reference voltage is the 9/10 of the 4th reference voltage absolute value.
In the above-mentioned constant pressure and flow Switching Power Supply of the embodiment of the present invention, described current rectifying and wave filtering circuit includes：Rectifier bridge and
First electric capacity, the input anode incoming transport power supply of rectifier bridge, the positive pole of the first electric capacity is rectified with the output of rectifier bridge respectively
One end of the input winding of pole, the first end of power supply circuits and transformer connects, and the negative pole of the first electric capacity is exported with rectifier bridge
End negative pole is all connected with one end of current sense resistor.
In the above-mentioned constant pressure and flow Switching Power Supply of the embodiment of the present invention, described power supply circuits include：3rd resistor and
Two electric capacity, one end of 3rd resistor is connected with the positive pole of the first electric capacity and one end of transformer input winding respectively, 3rd resistor
The other end be connected with the positive pole of the second electric capacity and the second pin of constant pressure and flow controller respectively, the negative pole of the second electric capacity with electricity
The other end common ground of stream detection resistance.
The beneficial effect that technical scheme provided in an embodiment of the present invention is brought is：
When being under constant voltage or constant current mode by constant pressure and flow Switching Power Supply, constant pressure and flow controller is at each
Switch periods active detecting power supply circuits output end provide operating voltage, and according to its size determine power supply circuits the need of
Charge, stop power supply when operating voltage is higher than the second reference voltage, recover when operating voltage is less than the second reference voltage to supply
Electricity is not so that operating voltage is with the change of power output, it is to avoid the loaded down with trivial details design debugging of power supply circuits.Additionally, also reducing permanent
The voltage request at pressure constant-current controller second pin end is so as to constant pressure and flow controller can use the 5V CMOS technology system of standard
Make, reduce the production cost of constant pressure and flow Switching Power Supply.Also save except afterflow diode of the prior art, the system of having saved simultaneously
Cause this.
Brief description
For the technical scheme being illustrated more clearly that in the embodiment of the present invention, will make to required in embodiment description below
Accompanying drawing be briefly described it should be apparent that, drawings in the following description are only some embodiments of the present invention, for
For those of ordinary skill in the art, on the premise of not paying creative work, other can also be obtained according to these accompanying drawings
Accompanying drawing.
Fig. 1 is a kind of circuit diagram of constant pressure and flow Switching Power Supply that prior art provides；
Fig. 2 is a kind of circuit diagram of constant pressure and flow Switching Power Supply provided in an embodiment of the present invention；
It is many in circuit under constant voltage mode of operation that Fig. 3 is that a kind of constant pressure and flow Switching Power Supply provided in an embodiment of the present invention is in
The voltage oscillogram of individual node.
Specific embodiment
For making the object, technical solutions and advantages of the present invention clearer, below in conjunction with accompanying drawing to embodiment party of the present invention
Formula is described in further detail.
Embodiment
Embodiments provide a kind of constant pressure and flow Switching Power Supply, referring to Fig. 2, this constant pressure and flow Switching Power Supply is permissible
Including：
Transformer 1, main switch Q1 (for triode), constant pressure and flow controller 3, power supply circuits 4, bleeder circuit 5, electric current
Detection resistance 6 and current rectifying and wave filtering circuit 7.
The positive pole of current rectifying and wave filtering circuit 7 input one end of winding NP and the first end of power supply circuits 4 with transformer 1 respectively
Connect, negative pole one end and the constant pressure and flow controller 3 first pin VCS with current sense resistor 6 respectively of current rectifying and wave filtering circuit 7
Connect, power supply circuits 4 output end is connected with constant pressure and flow controller 3 second pin VCC, the other end of current sense resistor 6, confession
Second end of circuit 4 and constant pressure and flow controller 3 the 3rd pin GND common ground.
Transformer 1 input winding NP the other end be connected with the colelctor electrode of main switch Q1, the base stage of main switch Q1 with
Emitter stage is connected with the 4th pin VB and the 5th pin VE of constant pressure and flow controller 3 respectively, assists winding NA of transformer 1
Two ends are connected with bleeder circuit 5 respectively, and bleeder circuit 5 is also connected with the 6th pin FB of constant pressure and flow controller 3.
Constant pressure and flow controller 3 is used for according to the feedback voltage receiving on bleeder circuit 5 with default first with reference to electricity
Relation between pressure, controls constant pressure and flow Switching Power Supply to be operated pattern switching, this mode of operation includes：Constant voltage mode of operation
Or constant current mode.In actual applications, when feedback voltage is less than the first reference voltage, constant pressure and flow Switching Power Supply will
Enter constant current mode, under constant current mode, constant pressure and flow switch power supply output current keep constant, output voltage with
Load change and change；When feedback voltage is more than the first reference voltage, constant pressure and flow Switching Power Supply will enter constant voltage work
Pattern, under constant voltage mode of operation, constant pressure and flow switch power source output voltage keeps constant, and output current becomes with load change
Change.It should be noted that this feedback voltage and the first reference voltage are negative voltage, feedback voltage is less than the first reference voltage
When, the absolute value of feedback voltage is more than the absolute value of the first reference voltage.
Constant pressure and flow controller 3 is additionally operable to the operating voltage providing according to power supply circuits 4 output end and default second ginseng
Examine the relation between voltage, to judge power supply circuits 4 the need of being charged.In the present embodiment, when power supply circuits 4 export
When the operating voltage that end provides is less than the second reference voltage, power supply circuits 4 need to be charged, when power supply circuits 4 output end carries
For operating voltage be more than the second reference voltage when, power supply circuits 4 are without being charged.
Transformer 1 is used for inputting the input voltage of winding NP according to it, controls the output voltage in its output winding NS；Main
Switching tube Q1 is used for the dutycycle controlling transformer 1 to input input voltage (i.e. original edge voltage) in winding NP, to adjust transformer 1
Output voltage；Power supply circuits 4 are used for providing operating voltage for constant pressure and flow controller 3；Feedback circuit 5 is used for constant pressure and flow
Controller 3 feedback transformer 1 exports the output voltage in winding NS；Current sense resistor 6 is used for carrying for constant pressure and flow controller 3
For the primary current Ip flowing through in input winding NP that can be detected.
In the present embodiment, constant pressure and flow controller 3 provides in each switch periods active detecting power supply circuits 4 output end
Operating voltage, and power supply circuits 4 are determined the need of charging according to its size, when operating voltage is higher than the second reference voltage
Stop power supply, restore electricity so that operating voltage is not with the change of power output when operating voltage is less than the second reference voltage,
Avoid the loaded down with trivial details design debugging of power supply circuits 4.Additionally, the voltage also reducing constant pressure and flow controller 3 second pin VCC end will
Ask so as to constant pressure and flow controller 3 can use the 5V CMOS technology manufacture of standard, reduce the production of constant pressure and flow Switching Power Supply
Cost.Also save except afterflow diode of the prior art simultaneously, saved manufacturing cost.
Specifically, referring to Fig. 2, constant pressure and flow controller 3 can include：First comparator 31, the second comparator the 32, the 3rd
Comparator 33, the 4th comparator 34, logic circuit 35, drive circuit 36, current source Ib, first switch K1, second switch K2,
Three switch K3, the 4th switch K0.
The negative-phase input of first comparator 31 is connected with bleeder circuit 5, and its normal phase input end accesses default first ginseng
Examine voltage Vref_FB, its output end is connected with logic circuit 35, when the feedback voltage that first comparator 31 receives is less than first
During reference voltage Vref _ FB, the first level signal FB_CV that logic circuit 35 exports according to first comparator 31, control constant voltage
Constant-current switch power source enters constant current mode, when the feedback voltage that first comparator 31 receives is more than the first reference voltage
When, the first level signal FB_CV that logic circuit 35 exports according to first comparator 31, control constant pressure and flow Switching Power Supply to enter
Constant voltage mode of operation.
The normal phase input end of the second comparator 32 is connected with the output end of power supply circuits 4, and its negative-phase input accesses default
The second reference voltage Vref _ vcc, its output end is connected with logic circuit 35, and logic circuit 35 is in constant pressure and flow Switching Power Supply
When entering constant voltage mode of operation, judge power supply circuits 4 whether according to the second electrical level signal VCC_S of the second comparator 32 output
Needs are charged.
The normal phase input end of the 3rd comparator 33 is connected with one end of current sense resistor 6, and its negative-phase input accesses pre-
If the 3rd reference voltage Vref 0, its output end is connected with logic circuit 35, and logic circuit 35 enters in constant pressure and flow Switching Power Supply
When entering constant voltage mode of operation, judge whether to open to confession according to the three level signal Pre_off of the 3rd comparator 33 output
The charging of circuit 4.
The normal phase input end of the 4th comparator 34 is connected with one end of current sense resistor 6, and its negative-phase input accesses pre-
If the 4th reference voltage Vref, its output end is connected with logic circuit 35, and logic circuit 35 enters in constant pressure and flow Switching Power Supply
When entering constant voltage mode of operation, power supply circuits 4 charging interval is limited according to the 4th level signal off of the 4th comparator 34 output
Maximum, the 4th reference voltage Vref be less than the 3rd reference voltage Vref 0.
The also fixing output recurrent pulses control signal of logic circuit 35, to control the conducting of first switch K1, drives electricity
Road 36 respectively with first switch K1, second switch K2, the 3rd switch K3, the 4th switch control end of K0 and logic circuit 35
Connect, for control signal export according to logic circuit 35, control first switch K1, second switch K2, the 3rd switch K3, the
The working condition (being switched on or off) of four switch K0；
One end of first switch K1 is connected with power supply circuits 4 output end by current source Ib and its other end is respectively with second
The base stage of switch one end of K2 and main switch Q1 connects, the other end ground connection of second switch K2, one end of the 3rd switch K3 with
Power supply circuits 4 output end connects and its other end is connected with one end of the 4th switch K0, and the 4th switchs the other end and the electric current of K0
The other end common ground of detection resistance 6.
In the present embodiment, under constant voltage mode of operation, when the conducting of first switch K1, second switch K2 closes, the 3rd switchs
When K3 closes, the 4th switch K0 turns on, constant pressure and flow Switching Power Supply is in normal power supply state；Close when first switch K1, the
Two switch K2 close, the 3rd switch K3 turns on, the 4th switch K0 closes, in a period of main switch Q1 late release, constant voltage
Constant-current switch power source is charged to power supply circuits 4；When the closing of first switch K1, second switch K2 conducting, main switch Q1
Close.
Further, referring to Fig. 2, bleeder circuit 5 includes：First resistor Rf1 and second resistance Rf2, first resistor Rf1
One end is connected with one end of assists winding NA of transformer 1, the other end of first resistor Rf1 respectively with second resistance Rf2 one
6th pin FB of end and constant pressure and flow controller 3 connects, assists winding NA of the other end of second resistance Rf2 and transformer 1
Other end common ground.
In the present embodiment, bleeder circuit 5 is used for the feedback current in assists winding NA the form by feedback voltage
Feed back in the first comparator 31 in constant pressure and flow controller 3, be compared with default first reference voltage Vref _ FB,
So that constant pressure and flow controller 3 switches the mode of operation of constant pressure and flow Switching Power Supply.Feedback current is input winding NP to defeated
Go out winding NS carry out energy transmission while, be transferred in assists winding NA, its with export winding NS on output current have
Corresponding relation, can reflect the change of the output current on output winding NS.
Further, the 4th reference voltage and the 3rd reference voltage are negative voltage, and the 3rd reference voltage is absolute
It is worth 9/10 for the 4th reference voltage absolute value.
In the present embodiment, due to flowing into the electric current of the first pin VCS of constant pressure and flow controller 3, first ground connection can be flowed through,
Then flow through current sense resistor 6, therefore, the voltage accessing the normal phase input end of the 3rd comparator 33 and the 4th comparator 34 is equal
For negative voltage, so the 4th reference voltage and the 3rd reference voltage are also all chosen for negative voltage.In actual applications, preferably
The absolute value of the 3rd reference voltage is the 9/10 of the 4th reference voltage absolute value, so can control power supply circuits 4 charging when
Between in OK range.
Specifically, referring to Fig. 2, current rectifying and wave filtering circuit 7 can include：Rectifier bridge 71 and the first electric capacity Cin, rectifier bridge 71
Input anode incoming transport power supply, positive pole output head anode, the power supply circuits 4 with rectifier bridge 71 respectively of the first electric capacity Cin
First end and one end of input winding NP of transformer 1 connect, the negative pole of the first electric capacity Cin and rectifier bridge 71 output end
Negative pole is all connected with one end of current sense resistor 6.
In the present embodiment, the AC power accessing constant pressure and flow Switching Power Supply passes through current rectifying and wave filtering circuit 7, can obtain
Export stable direct current, use for subsequent conditioning circuit.
Further, referring to Fig. 2, power supply circuits 4 include：3rd resistor Rst and the second electric capacity C0,3rd resistor Rst
One end is connected with the positive pole of the first electric capacity Cin and one end of transformer 1 input winding NP respectively, the other end of 3rd resistor Rst
Be connected with the positive pole of the second electric capacity C0 and second pin VCC of constant pressure and flow controller 3 respectively, the negative pole of the second electric capacity C0 with electricity
The other end common ground of stream detection resistance 6.
In the present embodiment, power supply circuits 4 pass through the second electric capacity C0 provides operating voltage for constant pressure and flow controller 3, supplies
When circuit 4 charges, it is also to charge for the second electric capacity C0.3rd resistor Rst is used for just starting in constant pressure and flow Switching Power Supply
When, it is that the second electric capacity C0 charges, now, constant pressure and flow controller 3 does not have started work.
With reference to Fig. 2 and Fig. 3, briefly explain the operation principle of constant pressure and flow Switching Power Supply.
Generally, when constant pressure and flow Switching Power Supply is started working, less, now, first compares its output current
The feedback voltage that device 31 receives is more than the first reference voltage Vref _ FB, and constant pressure and flow Switching Power Supply is in constant voltage mode of operation.
Wherein, feedback voltage be more than the first reference voltage Vref _ FB, reflection, constant pressure and flow Switching Power Supply output electric current (its with
Feedback current in assists winding NA has corresponding relation) it is less than preset reference electric current, now, constant pressure and flow Switching Power Supply keeps electricity
Pressure output is stable.
Under constant voltage mode of operation, logic circuit 35 fixing output recurrent pulses control signal, drive circuit 36 basis
The voltage Von1 of recurrent pulses control signal timing controlled first switch K1 is adjusted to high level, and meanwhile, drive circuit 36 is also
Second switch K2 can be controlled to close (voltage Voff is adjusted to low level), control the 3rd switch K3 to close and (voltage Vch is adjusted
For low level), control the 4th switch K0 open (voltage Von0 is adjusted to high level), the base stage of such main switch Q1 with electricity
Stream source Ib connects, and main switch Q1 turns on, the input winding NP energising of transformer 1.
After main switch Q1 turns on, the second comparator 32 starts to compare power supply circuits 4 and exports constant pressure and flow controller 3
Second pin VCC at operating voltage and the second reference voltage Vref _ vcc magnitude relationship, if operating voltage is less than the
Two reference voltage Vref _ vcc, then the second electrical level signal VCC_S that the second comparator 32 exports is changed into low level, for logic circuit
35 control constant pressure and flow controllers 3 are charged to power supply circuits 4；If operating voltage be more than the second reference voltage Vref _
Vcc, then constant pressure and flow controller 3 power supply circuits 4 are not charged control.
While main switch Q1 turns on, flow through the primary current IP of the input winding NP of transformer 1, flow through main switch
Pipe Q1, the 5th pin VE of constant pressure and flow controller 3, the 4th switch K0, the 3rd pin GND of constant pressure and flow controller 3 are followed by
Ground, after then passing through current sense resistor 6, a road enters the negative pole of the first electric capacity Cin, and another road enters constant pressure and flow and controls
First pin VCS of device 3.Voltage at such first pin VCS reduces with the increase of primary current IP (because former limit electricity
Stream IP can generate a negative voltage at the first pin VCS, and the absolute value of this negative voltage is with the increase of primary current IP
And increase).
If operating voltage is less than the second reference voltage Vref _ vcc (i.e. second electrical level signal VCC_S is changed into low level),
Then check the comparative result of the 3rd controller 33.Voltage at constant pressure and flow controller 3 first pin VCS compares less than the 3rd
During the voltage Vref0 of the negative-phase input of device 33, the three level signal Pre_off of the 3rd comparator 33 output changes,
So that drive circuit 36 controls the second electric capacity C0 to start to charge up, first switch K1 is specially controlled to close (because triode is closed
Time delay, now main switch Q1 is still conducting), control the 4th switch K0 close, control the 3rd switch K3 open.This
When, primary current IP flow through the 5th pin VE of constant pressure and flow controller 3, the 3rd switch K3, the second of constant pressure and flow controller 3
After pin VCC, enter into the second electric capacity C0, and the second electric capacity C0 is started to charge up.
And the primary current flowing through the second electric capacity C0 can first be grounded, then after flowing through current sense resistor 6, a road enters
The negative pole of the first electric capacity Cin, another road enters the first pin VCS of constant pressure and flow controller 3.So charge in the second electric capacity C0
When, the voltage at the first pin VCS is still reducing.
Voltage at constant pressure and flow controller 3 first pin VCS decreases below the 4th comparator 34 negative-phase input
During four reference voltage Vref accessing, the 4th level signal off change of the 4th comparator 34 output end output, so that drive
Circuit 36 terminates the charging to the second electric capacity C0, specifically, drive circuit 36 controls second switch K2 conducting so that main switch
Electric charge in Q1 base stage is released rapidly, and main switch Q1 closes, and after main switch Q1 closes, does not have primary current IP to draw first
Negative voltage is produced so that the voltage at the first pin VCS gos up rapidly at pin VCS.Now, the input winding NP of transformer 1
In energy be transformed in output loading, so go round and begin again.
If it should be noted that the load that constant pressure and flow Switching Power Supply connects diminishes, its output current is caused to become big, directly
To more than default reference current when, the feedback voltage that first comparator 31 receives will less than the first reference voltage Vref _ FB,
Now, constant pressure and flow Switching Power Supply will be switched to constant current mode, now, constant pressure and flow Switching Power Supply keeps electric current defeated
Go out stable.
When the embodiment of the present invention is under constant voltage or constant current mode by constant pressure and flow Switching Power Supply, constant pressure and flow
The operating voltage that controller provides in each switch periods active detecting power supply circuits output end, and power supply is determined according to its size
Circuit, the need of charging, is stopped power supply when operating voltage is higher than the second reference voltage, when operating voltage is less than the second reference
Restore electricity so that operating voltage is not with the change of power output during voltage, it is to avoid the loaded down with trivial details design debugging of power supply circuits.This
Outward, also reduce the voltage request at constant pressure and flow controller second pin end so as to constant pressure and flow controller can use the 5V of standard
CMOS technology manufactures, and reduces the production cost of constant pressure and flow Switching Power Supply.Also save except two grades of afterflow of the prior art simultaneously
Pipe, has saved manufacturing cost.
The foregoing is only presently preferred embodiments of the present invention, not in order to limit the present invention, all spirit in the present invention and
Within principle, any modification, equivalent substitution and improvement made etc., should be included within the scope of the present invention.
Claims (6)
1. a kind of constant pressure and flow Switching Power Supply is it is characterised in that include：Transformer (1), main switch (Q1), constant pressure and flow control
Device (3) processed, power supply circuits (4), bleeder circuit (5), current sense resistor (6), current rectifying and wave filtering circuit (7),
The positive pole of current rectifying and wave filtering circuit (7) respectively with one end of the input winding (NP) of transformer (1) and power supply circuits (4)
One end connects, negative pole one end and the constant pressure and flow controller (3) with current sense resistor (6) respectively of current rectifying and wave filtering circuit (7)
First pin (VCS) connects, and power supply circuits (4) output end is connected with constant pressure and flow controller (3) second pin (VCC), electric current
The other end of detection resistance (6), the second end of power supply circuits (4) and constant pressure and flow controller (3) the 3rd pin (GND) are altogether
With ground connection,
The other end that transformer (1) inputs winding (NP) is connected with the colelctor electrode of main switch (Q1), the base of main switch (Q1)
Pole and emitter stage are connected with the 4th pin (VB) of constant pressure and flow controller (3) and the 5th pin (VE) respectively, transformer (1)
The two ends of assists winding (NA) are connected with bleeder circuit (5) respectively, and bleeder circuit (5) also with constant pressure and flow controller (3)
6th pin (FB) connects,
Constant pressure and flow controller (3) is used for according to the feedback voltage receiving on bleeder circuit (5) with default first with reference to electricity
Relation between pressure, controls constant pressure and flow Switching Power Supply to be operated pattern switching, described mode of operation includes：Constant voltage Working mould
Formula or constant current mode；
Constant pressure and flow controller (3) is additionally operable to the operating voltage providing according to power supply circuits (4) output end and default second ginseng
Examine the relation between voltage, to judge power supply circuits (4) the need of being charged.
2. constant pressure and flow Switching Power Supply according to claim 1 is it is characterised in that described constant pressure and flow controller (3) wraps
Include：First comparator (31), the second comparator (32), the 3rd comparator (33), the 4th comparator (34), logic circuit (35),
Drive circuit (36), current source (Ib), first switch (K1), second switch (K2), the 3rd switch (K3), the 4th switch (K0),
The negative-phase input of first comparator (31) is connected with bleeder circuit (5), and its normal phase input end accesses default first ginseng
Examine voltage, its output end is connected with logic circuit (35), when the feedback voltage that first comparator (31) receives is less than the first ginseng
When examining voltage, the first level signal that logic circuit (35) exports according to first comparator (31), control constant pressure and flow switch electricity
Source enters constant current mode, when the feedback voltage that first comparator (31) receives is more than the first reference voltage, logic electricity
The first level signal that road (35) exports according to first comparator (31), controls constant pressure and flow Switching Power Supply to enter constant voltage Working mould
Formula；
The normal phase input end of the second comparator (32) is connected with the output end of power supply circuits (4), and its negative-phase input accesses default
The second reference voltage, its output end is connected with logic circuit (35), and logic circuit (35) enters in constant pressure and flow Switching Power Supply
During constant voltage mode of operation, according to the second electrical level signal that the second comparator (32) exports judge power supply circuits (4) the need of
It is charged；
The normal phase input end of the 3rd comparator (33) is connected with one end of current sense resistor (6), and its negative-phase input accesses pre-
If the 3rd reference voltage, its output end is connected with logic circuit (35), and logic circuit (35) enters in constant pressure and flow Switching Power Supply
When entering constant voltage mode of operation, judge whether to open to power supply circuits according to the three level signal that the 3rd comparator (33) exports
(4) charging；
The normal phase input end of the 4th comparator (34) is connected with one end of current sense resistor (6), and its negative-phase input accesses pre-
If the 4th reference voltage, its output end is connected with logic circuit (35), and logic circuit (35) enters in constant pressure and flow Switching Power Supply
When entering constant voltage mode of operation, when power supply circuits (4) charging is limited according to the 4th level signal that the 4th comparator (34) exports
Between maximum, the 4th reference voltage be less than the 3rd reference voltage；
The also fixing output recurrent pulses control signal of logic circuit (35), to control the conducting of first switch (K1), drives electricity
Road (36) respectively with first switch (K1), second switch (K2), the 3rd switch (K3), the 4th switch (K0) control end and
Logic circuit (35) connects, and for the control signal exporting according to logic circuit (35), controls first switch (K1), second switch
(K2), the 3rd switch (K3), the working condition of the 4th switch (K0)；
One end of first switch (K1) is connected with power supply circuits (4) output end by current source (Ib) and its other end is respectively with
The base stage of one end of two switches (K2) and main switch (Q1) connects, the other end ground connection of second switch (K2), the 3rd switch
(K3) one end is connected with power supply circuits (4) output end and its other end is connected with one end of the 4th switch (K0), the 4th switch
(K0) the other end and the other end common ground of current sense resistor (6).
3. constant pressure and flow Switching Power Supply according to claim 2 is it is characterised in that described bleeder circuit (5) includes：First
Resistance (Rf1) and second resistance (Rf2), one end of first resistor (Rf1) is connected with one end of the assists winding (NA) of transformer (1)
Connect, the other end of first resistor (Rf1) is drawn with one end of second resistance (Rf2) and the 6th of constant pressure and flow controller (3) respectively
Pin (FB) connects, the other end common ground of the assists winding (NA) of the other end of second resistance (Rf2) and transformer (1).
4. constant pressure and flow Switching Power Supply according to claim 2 is it is characterised in that the 4th reference voltage and the 3rd is with reference to electricity
Pressure is negative voltage, and the absolute value of the 3rd reference voltage is the 9/10 of the 4th reference voltage absolute value.
5. constant pressure and flow Switching Power Supply according to claim 1 is it is characterised in that described current rectifying and wave filtering circuit (7) includes：
Rectifier bridge (71) and the first electric capacity (Cin), the input anode incoming transport power supply of rectifier bridge (71), the first electric capacity (Cin)
The positive pole input winding with the output head anode, the first end of power supply circuits (4) and transformer (1) of rectifier bridge (71) respectively
(NP) one end connects, the negative pole of the first electric capacity (Cin) and rectifier bridge (71) negative pole of output end all with current sense resistor (6)
One end connects.
6. constant pressure and flow Switching Power Supply according to claim 5 is it is characterised in that described power supply circuits (4) include：3rd
Resistance (Rst) and the second electric capacity (C0), one end positive pole and transformer with the first electric capacity (Cin) respectively of 3rd resistor (Rst)
(1) one end of input winding (NP) connects, other end positive pole and the constant voltage with the second electric capacity (C0) respectively of 3rd resistor (Rst)
The second pin (VCC) of constant-current controller (3) connects, the other end of the negative pole of the second electric capacity (C0) and current sense resistor (6)
Common ground.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201610848251.4A CN106385186A (en) | 2016-09-23 | 2016-09-23 | Constant-voltage constant-current switching power source |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610848251.4A CN106385186A (en) | 2016-09-23 | 2016-09-23 | Constant-voltage constant-current switching power source |
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| CN201610848251.4A Pending CN106385186A (en) | 2016-09-23 | 2016-09-23 | Constant-voltage constant-current switching power source |
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| CN106787767A (en) * | 2017-02-17 | 2017-05-31 | 辉芒微电子（深圳）有限公司 | A kind of Switching Power Supply with multistage Darlington transistor |
| CN110611433A (en) * | 2019-10-18 | 2019-12-24 | 深圳原能电器有限公司 | Novel loop detection and control circuit |
| CN110768537A (en) * | 2019-11-20 | 2020-02-07 | 深圳原能电器有限公司 | Bilateral feedback and control DSR framework |
| CN111953209A (en) * | 2020-08-07 | 2020-11-17 | 矽力杰半导体技术(杭州)有限公司 | Switch type converter and control circuit and control method thereof |
| CN112653321A (en) * | 2020-12-24 | 2021-04-13 | 上海汽车工业(集团)总公司 | Cross overvoltage comparison circuit and EPS power module |
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| CN110768537A (en) * | 2019-11-20 | 2020-02-07 | 深圳原能电器有限公司 | Bilateral feedback and control DSR framework |
| CN110768537B (en) * | 2019-11-20 | 2021-07-16 | 深圳原能电器有限公司 | Bilateral feedback and control DSR framework |
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| CN112653321A (en) * | 2020-12-24 | 2021-04-13 | 上海汽车工业(集团)总公司 | Cross overvoltage comparison circuit and EPS power module |
| CN112653321B (en) * | 2020-12-24 | 2022-08-26 | 上海汽车工业(集团)总公司 | Cross overvoltage comparison circuit and EPS power module |
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