CN106849667B - A kind of primary side feedback constant pressure and flow controller sample circuit - Google Patents
A kind of primary side feedback constant pressure and flow controller sample circuit Download PDFInfo
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- CN106849667B CN106849667B CN201710067962.2A CN201710067962A CN106849667B CN 106849667 B CN106849667 B CN 106849667B CN 201710067962 A CN201710067962 A CN 201710067962A CN 106849667 B CN106849667 B CN 106849667B
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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
- 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
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Abstract
The invention discloses a kind of primary side feedback constant pressure and flow controller sample circuits, suitable for the primary side feedback constant pressure and flow controller with auxiliary winding transformer, comprising: divider, degaussing end detection circuit, filter circuit, logic circuit, sampled signal control switch, sampling capacitance.A kind of primary side feedback constant pressure and flow controller sample circuit, it is combined using degaussing end detection circuit and logic circuit, auxiliary winding voltage is acquired in degaussing finish time, avoid complicated iterative algorithm circuit, circuit structure is simple, the error of average value sampling method is also avoided, and then obtains more accurate output voltage.
Description
Technical field
The present invention relates to integrated circuit fields more particularly to a kind of primary side feedback constant pressure and flow controller sample circuits.
Background technique
In recent years, hand-held personal telecommunication terminal product is quickly grown, and related charger market is developed therewith.Inverse-excitation type
Converter is widely used in this field due to its own cost, performance advantage, and the various constant pressure and constants using primary side feedback
Stream controller is widely accepted and applies because its peripheral structure is simple, low in cost.
Generally, in inverse-excitation type pwm converter, there are two kinds of feedback systems, one is traditional secondary feedback, one is
Novel primary side feedback.Since primary side feedback eliminates the sample circuit of secondary feedback, without using TL431 and photo-coupler,
Reduce peripheral original part, reduce the complexity of circuit, more optimization is with efficiently, and therefore, primary side feedback is more widely applied.
Using the controller of primary side feedback structure, constant pressure, constant current and the precision of sampling of output have substantial connection, primary side feedback structure
Controller reaches the control to constant pressure precision, therefore, the precision of sampling determines output electricity by sampling to auxiliary winding voltage
The precision of pressure.
Fig. 1 is the schematic diagram of existing primary side feedback controller, and primary side feedback controller includes that transformer, divider, S/H are adopted
Sample circuit, error amplifier OP1, pwm control circuit, switching transistor M0, sampling resistor Rs, rectifier diode Df, output electricity
Hold Co, output resistance Ro, the transformer includes primary side winding p, auxiliary winding a and secondary windings s, and the divider includes the
One divider resistance R1 and the second divider resistance R2, connect the first divider resistance R1 and the at the transformer auxiliary winding a different name end
Two divider resistance R2 ground connection, cathode ground connection, the connecting node between the first divider resistance R1 and the second divider resistance R2, which is used as, divides
Depressor output end is connect with the input terminal of S/H sample circuit, and the output end connection error amplifier OP1's of S/H sample circuit is anti-
Phase input terminal, the non-inverting input terminal of error amplifier OP1 connect a reference voltage Vref, and the output end of error amplifier OP1 connects
Connect the input terminal of pwm control circuit, the grid of pwm control circuit output end connection switch transistor M0, switching transistor M0's
Source electrode is separately connected the CS leads ends of pwm control circuit and the output end of divider, and the CS pin is the inspection of primary side winding p electric current
It surveys signal and introduces foot, for detecting electric current when primary side winding p conducting, the source electrode of switching transistor M0 also passes through connection sampling electricity
Hinder Rs ground connection, the different name end of the drain electrode connection primary side winding p of switching transistor M0, the different name end series rectifier two of secondary windings s
Pole pipe Df, secondary windings s are also in parallel with output capacitance Co and output resistance Ro, output voltage Vo.In Fig. 1, Vd indicates that switch is brilliant
Body pipe M0 drain voltage, Vin indication transformer primary side winding p Same Name of Ends voltage, Ip are primary current, and Vf indicates rectifier diode
The voltage of Df, Is are the secondary current for flowing through rectifier diode Df, and Va indication transformer auxiliary winding a voltage, Np is transformer
The number of turns of primary side winding p, Ns are the number of turns of transformer secondary output winding s, and Na is the number of turns of transformer auxiliary winding a. When secondary current Is is zero, Vf=0, at this time primary side winding p
VoltageAuxiliary winding a voltageAs can be seen that switching transistor M0 drain electrode from formula
Both voltage Vd and auxiliary winding a voltage Va are determined by the value of Vo completely, are not influenced by secondary commutation diode voltage Vf, because
This, is if can be sampled at the time of secondary windings s electric current is zero, i.e., at the end of degaussing to the voltage Va of auxiliary winding a,
Accurate output voltage Vo can just be obtained.
For S/H sample circuit in Fig. 1, at present there are two ways to sampling, one is can accurately sample degaussing to terminate
The iterative algorithm of moment auxiliary winding voltage, another kind are the voltage in degaussing pilot process sampling auxiliary winding.Iterative algorithm
Sampling process be the relatively variation difference of front and back twice by the voltage of the multi collect auxiliary winding in demagnetization process, when
When front and back changes greatly twice, that is, think that previous sampling is sampling at the time of degaussing terminates, such implementation method obtains
The sampled value obtained is relatively accurate, can obtain high-precision output voltage Vo, but the circuit that iterative algorithm needs is complicated,
Design cost is high.And the degaussing intermediate time method of sampling is that average voltage is taken to Va, due to the electricity of auxiliary winding in demagnetization process
The shortcomings that pressing Va is linear decline, samples at the 1/2 of degaussing, is just the average value of Va, such method is, in degaussing
When sampling in journey, secondary winding current Is is not zero, cannot ignore the influence of output diode pressure drop, leads to output voltage Vo
Design value can be higher than, in addition, due to the circuit for the intermediate time for needing to calculate the degaussing time, circuit is also relatively complicated.
Summary of the invention
In order to solve the above-mentioned technical problem, the object of the present invention is to provide a kind of simple, accurate primary side feedback constant pressures
Constant-current controller sample circuit.
The technical scheme adopted by the invention is that: a kind of primary side feedback constant pressure and flow controller sample circuit is suitable for tool
There is the primary side feedback constant pressure and flow controller of auxiliary winding transformer, comprising: divider, it is in series by two divider resistances,
For completing the partial pressure to the voltage in auxiliary winding；Degaussing end detection circuit passes through voltage change in detection auxiliary winding
Amplitude and speed, judge whether degaussing terminates；Filter circuit is filtered auxiliary winding voltage, filters out auxiliary in demagnetization process
Help the shake of voltage on winding, the output voltage of smooth divider；Logic circuit works as degaussing for generating control sampled signal
At the end of end detection circuit detects degaussing, logic circuit issues sampled signal；Sampled signal control switch is believed by sampling
The opening and shutdown of number control switch complete the sampling to auxiliary winding voltage；Sampling capacitance, for storing sampled signal.
As a further improvement of the foregoing solution, the divider includes the first divider resistance and the second divider resistance, institute
The different name end of auxiliary winding is stated by the first divider resistance of series connection and the second divider resistance ground connection, first divider resistance and the
Output end of the connecting node as divider between two divider resistances.
As a further improvement of the foregoing solution, the output end of the input terminal and divider of the degaussing end detection circuit
Connection, the output end of the degaussing end detection circuit and the input terminal of logic circuit connect.
As a further improvement of the foregoing solution, the degaussing end detection circuit includes follower, the follower packet
Include operational amplifier and 3rd resistor, the non-inverting input terminal of the operational amplifier and the first divider resistance and the second divider resistance
Connecting node connection, the output end of the operational amplifier and one end of 3rd resistor connect, the other end of the 3rd resistor
It is connect with the inverting input terminal of operational amplifier.
As a further improvement of the foregoing solution, the degaussing end detection circuit further includes comparator, the 4th resistance,
One filter capacitor, current source, electric current be heavy and phase inverter, the output end of the operational amplifier also with the inverting input terminal of comparator
Connection, the output end of the follower by connection the first filter capacitor ground connection, the output end of the follower also with current source
Connection, the output end of the follower also passes through the 4th resistance of connection and the non-inverting input terminal of comparator connects, the comparator
Non-inverting input terminal by the heavy ground connection of connection electric current, the output end of the comparator respectively with the input terminal of phase inverter and logic circuit
Input terminal connection.
As a further improvement of the foregoing solution, the sampled signal control switch include the first enabled switch NMOS tube,
Second switch NMOS tube and third switch NMOS tube, the grid of the enabled switch NMOS tube of output end connection first of the phase inverter
Pole, the logic circuit generate two-way sampling control signal, the first output end and second switch NMOS tube of the logic circuit
Grid connection, second output terminal and third switch NMOS tube grid connect, the source electrode of the described first enabled switch NMOS tube
Connect the drain electrode of second switch NMOS tube, the drain electrode of the source electrode connection third switch NMOS tube of the second switch NMOS tube.
As a further improvement of the foregoing solution, the sampling capacitance includes the 4th sampling capacitance and the 5th sampling capacitance,
The source electrode of the second switch NMOS tube is passed through by connection the 4th sampling capacitance ground connection, the source electrode of the third switch NMOS tube
Connect the 5th sampling capacitance ground connection.
As a further improvement of the foregoing solution, the filter circuit includes first order filter and second level filter,
The first order filter includes concatenated 5th resistance and the second filter capacitor, and the second level filter includes concatenated
Six resistance and third filter capacitor, the input terminal of the output end connection first order filter of the divider, the first order filter
The input terminal of the output end connection second level filter of wave device, the enabled switch of output end connection first of the second level filter
The drain electrode of NMOS tube.
The beneficial effects of the present invention are:
A kind of primary side feedback constant pressure and flow controller sample circuit, using degaussing end detection circuit and logic circuit knot
It closes, acquires auxiliary winding voltage in degaussing finish time, avoid complicated iterative algorithm circuit, circuit structure is simple, also avoids
The error of average value sampling method, and then obtain more accurate output voltage.
Detailed description of the invention
Specific embodiments of the present invention will be further explained with reference to the accompanying drawing:
Fig. 1 is the electrical block diagram of primary side feedback controller in the prior art；
Fig. 2 is the working waveform figure of each node of iterative algorithm sampling instant in Fig. 1 circuit structure；
Fig. 3 is the working waveform figure that degaussing intermediate time samples each node in Fig. 1 circuit structure；
Fig. 4 is a kind of circuit structure diagram of primary side feedback constant pressure and flow controller sample circuit specific embodiment of the present invention；
Fig. 5 is respectively saved in a kind of primary side feedback constant pressure and flow controller sample circuit specific embodiment circuit structure of the present invention
The working waveform figure of point；
Fig. 6 is sampled in a kind of primary side feedback constant pressure and flow controller sample circuit specific embodiment circuit structure of the present invention
Point moment waveform partial enlarged view.
Specific embodiment
It should be noted that in the absence of conflict, the features in the embodiments and the embodiments of the present application can phase
Mutually combination.
Fig. 2 is the working waveform figure of each node of iterative algorithm sampling instant in Fig. 1 circuit structure, including GATE, primary side electricity
The waveform diagram for flowing voltage Va on Ip, secondary current Is and auxiliary winding a, at non-continuous mode (DCM), as switching transistor M0
GATE open after, primary current Ip is linearly increasing, and slope isWherein Lp is primary side winding inductance, and transformer stores up energy
There are primary side winding, in switching transistor M0 cut-off, secondary current Is electric current linearly becomes smaller, and slope is energy from primary side winding
It is transmitted to secondary windingsWherein Ls is secondary winding inductance, output voltageWherein, tonTable
Show switching transistor M0 turn-on time, TsIndicate that the switch periods of primary side feedback controller, secondary output current areWherein, tdisThe degaussing time of indication transformer, Is,pkIndicate secondary electrical
Flow the peak value of Is, Ip,pkIndicate the peak value of primary current Ip.The voltage of auxiliary winding aWork as secondary current
When Is is zero, Vf=0, at this point, auxiliary winding a voltage isAs shown in Fig. 2, in auxiliary winding a voltage Va subscript
The sampling of note indicates degaussing finish time sampled point.
Fig. 3 is the working waveform figure that degaussing intermediate time samples each node in Fig. 1 circuit structure, and the difference of Fig. 3 and Fig. 2 exist
In for the sampled point of Fig. 3 in degaussing intermediate time, the sampling marked on auxiliary winding voltage Va indicates degaussing intermediate time
Sampled point.
Fig. 4 is a kind of circuit structure diagram of primary side feedback constant pressure and flow controller sample circuit specific embodiment of the present invention,
As shown in figure 4, a kind of primary side feedback constant pressure and flow controller sample circuit, including divider, by two divider resistances series connection structures
At for completing the partial pressure to the voltage Va in auxiliary winding；Degaussing end detection circuit 1 is powered on by detecting auxiliary winding
Va amplitude of variation and speed are pressed, judges whether degaussing terminates；Filter circuit 2 is filtered auxiliary winding voltage Va, filters out
During magnetic in auxiliary winding voltage Va shake, the output voltage Vfb of smooth divider；Logic circuit 3, for generating control
System sampling keeps signal, and at the end of degaussing end detection circuit 1 detects degaussing, logic circuit 3 issues sampled signal；Sampling
Signal-controlled switch completes the sampling to auxiliary winding voltage Va by using the opening and shutdown of Signal-controlled switch；Sampling
Capacitor, for storing sampled signal.
Fig. 5 is respectively saved in a kind of primary side feedback constant pressure and flow controller sample circuit specific embodiment circuit structure of the present invention
The working waveform figure of point, Fig. 6 are a kind of primary side feedback constant pressure and flow controller sample circuit specific embodiment circuit knots of the present invention
Point moment waveform partial enlarged view is sampled in structure, in conjunction with Fig. 4, Fig. 5 and Fig. 6, divider includes the first divider resistance R1 and second
The different name end of divider resistance R2, auxiliary winding are grounded by the first divider resistance R1 of series connection and the second divider resistance R2, and first point
Output end of the connecting node as divider between piezoresistance R1 and the second divider resistance R2, output partial pressure Vfb, degaussing terminate
The input terminal of the connection of the output end of the input terminal of detection circuit 1 and divider, output end and logic circuit 3 connects.
Degaussing end detection circuit 1 includes follower, and follower includes operational amplifier OP and 3rd resistor R3, and operation is put
The non-inverting input terminal of big device OP is connect with the first divider resistance R1 and the second divider resistance R2 connecting node, operational amplifier OP's
Output end and the inverting input terminal for being connected to operational amplifier OP by connecting 3rd resistor R3, constitute follower, for completing
Partial pressure Vfb is followed, i.e. Vfb=VN.Degaussing end detection circuit 1 further includes comparator COMP, the 4th resistance R4, the first filter
The heavy I2 and phase inverter UI of wave capacitor C1, current source I1, electric current, wherein the resistance value of the 4th resistance R4 is greater than the resistance of 3rd resistor R3
Value.In the present embodiment, the electric current of current source I1 is equal with the heavy electric current of I2 of electric current, I1=I2.The output end of operational amplifier OP
It is connect with the inverting input terminal of comparator COMP, VN=VN_CP, the output end of follower connects by connecting the first filter capacitor C1
Ground, the first filter capacitor C1 are used for the output voltage V to followerNIt is filtered, when the output voltage of operational amplifier OP is sent out
When raw acute variation, the first filter capacitor C1 can allow the output voltage V of followerNIt is smoother.The output end of follower is also
It is connect with current source I1, the non-inverting input terminal that the output end of follower also passes through the 4th resistance R4 of connection and comparator COMP connects
Connect, comparator COMP non-inverting input terminal by connection electric current sink I2 ground connection, the output end of comparator COMP respectively with phase inverter UI
Input terminal connected with the input terminal of logic circuit 3.Comparator COMP is used to compare current voltage and the sampling in auxiliary winding
The height of moment hair auxiliary winding voltage.Degaussing end detection circuit 1 in primary side winding demagnetization process, operational amplifier OP's
Output voltage closely follows operational amplifier OP homophase input end signal Vfb, in demagnetization process, under the voltage Va of auxiliary winding is slow
Drop, partial pressure Vfb also slowly decline, and the output voltage of operational amplifier OP is together with the non-inverting input terminal voltage of operational amplifier OP
Decline, the pressure drop of 3rd resistor R3 is zero, i.e., no electric current flows through, in demagnetization process, due to operational amplifier OP output end
The pressure drop of the 3rd resistor R3 of connection is zero, and the electric current of current source I1 all passes through the 4th resistance R4 and flows into the heavy I2 of electric current, the
Four resistance R4 are high, low with the heavy voltage of I2 connected end of electric current with the voltage of current source I1 connected end, i.e. VN>VP_CP, due to VN=
VN_CP, since the non-inverting input terminal of comparator COMP is connect with the heavy I2 of electric current, the output of inverting input terminal and operational amplifier OP
End connection, therefore, in demagnetization process, the non-inverting input terminal voltage of comparator COMP is lower than inverting input terminal voltage, i.e. VN_CP>
VP_CP, the output signal Slp_det of comparator is low level.In primary side winding degaussing finish time, auxiliary winding voltage Va hair
Raw acute variation, reduces rapidly, the non-inverting input terminal of operational amplifier OP detects this variation, the voltage of non-inverting input terminal
Acute variation is ensued, the output voltage of operational amplifier OP follows decline, due to the presence of the first filter capacitor C1, third
Resistance R3 both end voltage is no longer zero, i.e. the inverting input terminal of operational amplifier OP and the non-inverting input terminal of operational amplifier OP
There is difference in voltage, and the voltage difference of operational amplifier OP input terminal causes the variation of output voltage to be further exacerbated by, and circuit is formed
Positive feedback, positive feedback cause operational amplifier OP input terminal voltage difference to be further exacerbated by, at this point, the first end filter capacitor C1 voltage
Higher than operational amplifier OP output end voltage, the first filter capacitor C1 discharges to 3rd resistor R3 and operational amplifier OP.Due to
The resistance value of 3rd resistor R3 is greater than the resistance value of the 4th resistance R4, and during discharge, the voltage at the heavy end I2 of electric current is higher than fortune
Amplifier OP output voltage is calculated, the non-inverting input terminal voltage of comparator COMP is higher than inverting input terminal voltage, i.e. VN_CP≤VP_CPWhen
It carves, comparator COMP is flipped, and it is high level, comparator that the output signal Slp_det of comparator COMP is jumped from low level
As secondary winding current is zero moment at the time of COMP is jumped.
Sampled signal control switch includes the first enabled switch NMOS tube M1, second switch NMOS tube M2 and third switch
The grid of the enabled switch NMOS tube M1 of output end connection first of NMOS tube M3, phase inverter UI, logic circuit 3 generate two-way sampling
Signal is controlled, the first output end S1 of logic circuit 3 connect with the grid of second switch NMOS tube M2, second output terminal S2 and the
The grid connection of three switch NMOS tube M3, the leakage of the source electrode connection second switch NMOS tube M2 of the first enabled switch NMOS tube M1
Pole, the drain electrode of the source electrode connection third switch NMOS tube M3 of second switch NMOS tube M2.Sampling capacitance includes the 4th sampling capacitance
The source electrode of C4 and the 5th sampling capacitance C5, second switch NMOS tube M2 pass through connection the 4th sampling capacitance C4 ground connection, third switch
The source electrode of NMOS tube M3 switchs NMOS tube M3 source electrode and exports sampled voltage Vfb_ by connection the 5th sampling capacitance C5 ground connection, third
sh.Filter circuit 2 include first order filter and second level filter, first order filter include concatenated 5th resistance R5 and
Second filter capacitor C2, second level filter include concatenated 6th resistance R6 and third filter capacitor C3, the output of divider
The input terminal of end connection first filter, the input terminal of the output end connection second level filter of first order filter, the second level
The drain electrode of the enabled switch NMOS tube M1 of output end connection first of filter.The signal that degaussing end detection circuit 1 exports passes through
After the processing of logic circuit 3, generates sampling and keep signal, sampling keeps signal control sampling, keeps switch, completes to auxiliary winding
The sampling and holding of signal.Phase inverter UI enables when switch NMOS tube M1 samples auxiliary winding voltage for controlling first, the
One enabled switch NMOS tube M1 and then opening second switch NMOS tube M2 and third switch NMOS tube M3, by the voltage of auxiliary winding
Signal is stored to the 4th sampling capacitance C4 and the 5th sampling capacitance C5.The output signal Slp_det of comparator is admitted to logic electricity
Road 3, in detecting demagnetization process, comparator COMP output signal Slp_det is jumped logic circuit 3, i.e., can send out
The signal that magnetic knot beam samples auxiliary winding.Sampled signal passes through the switch of control NMOS tube, by the voltage signal of auxiliary winding
Vfb_sh is sampled on capacitor, and the signal is sent to error amplifier OP1 shown in FIG. 1, for completing the control of constant pressure.
As shown in Figure 5 and Figure 6, trembling for voltage Va in auxiliary winding is filtered out in demagnetization process under the action of filter circuit 2
It is dynamic, the output signal Slp_detb of the voltage Vfb of output smoothing, phase inverter UI and the comparator COMP output signal side Slp_det
To on the contrary, phase inverter UI the first output signal S1's and the second output signal S2 is contrary, third switchs NMOS tube M3 source electrode
Output signal Vfb_sh is more smooth than second switch NMOS tube M2 source output Vfb_s waveform, and precision is higher, is assisting
The sampling that marks on winding voltage Va indicates degaussing finish time sampled point, in the sampling of degaussing finish time, auxiliary around
Group partial pressure Vfb is lower than follower output voltage VN, comparator COMP anti-phase input terminal voltage signal VN_CPHigher than its non-inverting input terminal
Voltage signal VP_CP。
A kind of primary side feedback constant pressure and flow controller sample circuit, using degaussing end detection circuit and logic circuit knot
It closes, acquires auxiliary winding voltage in degaussing finish time, avoid complicated iterative algorithm circuit, circuit structure is simple, also avoids
The error of average value sampling method, and then obtain more accurate output voltage.
It is to be illustrated to preferable implementation of the invention, but the invention is not limited to the implementation above
Example, those skilled in the art can also make various equivalent variations on the premise of without prejudice to spirit of the invention or replace
It changes, these equivalent deformations or replacement are all included in the scope defined by the claims of the present application.
Claims (8)
1. a kind of primary side feedback constant pressure and flow controller sample circuit, permanent suitable for the primary side feedback with auxiliary winding transformer
Press constant-current controller, characterized in that it comprises:
Divider, it is in series by two divider resistances, for completing the partial pressure to the voltage in auxiliary winding；
Degaussing end detection circuit judges whether degaussing terminates by voltage change amplitude and speed in detection auxiliary winding；
Filter circuit is filtered auxiliary winding voltage, filters out the shake of voltage in auxiliary winding in demagnetization process, and smooth point
The output voltage of depressor；
Logic circuit, for generating control sampled signal, at the end of degaussing end detection circuit detects degaussing, logic circuit
Issue sampled signal；
Sampled signal control switch, by the opening and shutdown of sampled signal control switch, auxiliary winding voltage is adopted in completion
Sample；
Sampling capacitance, for storing sampled signal.
2. primary side feedback constant pressure and flow controller sample circuit according to claim 1, which is characterized in that the divider
Including the first divider resistance and the second divider resistance, the different name end of the auxiliary winding passes through series connection the first divider resistance and second
Divider resistance ground connection, output end of the connecting node as divider between first divider resistance and the second divider resistance.
3. primary side feedback constant pressure and flow controller sample circuit according to claim 2, which is characterized in that described to remove magnetic knot
The input terminal of beam detection circuit and the output end of divider connect, the output end and logic circuit of the degaussing end detection circuit
Input terminal connection.
4. primary side feedback constant pressure and flow controller sample circuit according to claim 2, which is characterized in that described to remove magnetic knot
Beam detection circuit includes follower, and the follower includes operational amplifier and 3rd resistor, the same phase of the operational amplifier
Input terminal is connect with the first divider resistance and the second divider resistance connecting node, output end and the third electricity of the operational amplifier
One end of resistance connects, and the other end of the 3rd resistor and the inverting input terminal of operational amplifier connect.
5. primary side feedback constant pressure and flow controller sample circuit according to claim 4, which is characterized in that described to remove magnetic knot
Beam detection circuit further includes comparator, the 4th resistance, the first filter capacitor, current source, electric current is heavy and phase inverter, the operation are put
The output end of big device is also connect with the inverting input terminal of comparator, and the output end of the follower passes through the first filter capacitor of connection
Ground connection, the output end of the follower also connect with current source, the output end of the follower also pass through the 4th resistance of connection and
The non-inverting input terminal of comparator connects, the comparator non-inverting input terminal by the heavy ground connection of connection electric current, the comparator it is defeated
Outlet is connect with the input terminal of the input terminal of phase inverter and logic circuit respectively.
6. primary side feedback constant pressure and flow controller sample circuit according to claim 5, which is characterized in that the sampling letter
Number control switch includes that the first enabled switch NMOS tube, second switch NMOS tube and third switch NMOS tube, the phase inverter
The grid of the enabled switch NMOS tube of output end connection first, the logic circuit generate two-way sampling control signal, the logic
First output end of circuit is connect with the grid of second switch NMOS tube, the grid of second output terminal and third switch NMOS tube connects
It connects, the drain electrode of the source electrode connection second switch NMOS tube of the described first enabled switch NMOS tube, the second switch NMOS tube
Source electrode connects the drain electrode of third switch NMOS tube.
7. primary side feedback constant pressure and flow controller sample circuit according to claim 6, which is characterized in that the sampling electricity
Holding includes the 4th sampling capacitance and the 5th sampling capacitance, and the source electrode of the second switch NMOS tube passes through the 4th sampling capacitance of connection
The source electrode of ground connection, the third switch NMOS tube passes through connection the 5th sampling capacitance ground connection.
8. primary side feedback constant pressure and flow controller sample circuit according to claim 7, which is characterized in that the filtered electrical
Road includes first order filter and second level filter, and the first order filter includes concatenated 5th resistance and the second filtering
Capacitor, the second level filter include concatenated 6th resistance and third filter capacitor, the output end connection of the divider
The input terminal of first order filter, the input terminal of the output end connection second level filter of the first order filter, described the
The drain electrode of the enabled switch NMOS tube of output end connection first of two-stage filter.
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| CN111462989B (en) * | 2020-04-27 | 2021-09-28 | 扬州中恒电气有限公司 | Secondary grounding protection device of voltage transformer |
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| CN101841250B (en) * | 2010-04-27 | 2012-08-15 | 上海新进半导体制造有限公司 | Switching power supply control circuit and primary winding-controlled flyback switching power supply |
| US9590511B2 (en) * | 2013-10-08 | 2017-03-07 | Rohm Co., Ltd. | Insulation type switching power source apparatus |
| JP6554888B2 (en) * | 2015-04-15 | 2019-08-07 | 富士電機株式会社 | Switching power supply |
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| CN102237812A (en) * | 2010-04-26 | 2011-11-09 | 辉芒微电子（深圳）有限公司 | Primary side feedback (FB) switching power supply controller and switching power supply system |
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| CN205142036U (en) * | 2015-07-19 | 2016-04-06 | 珠海市竞争电子科技有限公司 | Adopt power control circuit of former limit feedback |
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