CN104601015B - Inverse-excitation type AC DC converters - Google Patents
Inverse-excitation type AC DC converters Download PDFInfo
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- CN104601015B CN104601015B CN201410015595.8A CN201410015595A CN104601015B CN 104601015 B CN104601015 B CN 104601015B CN 201410015595 A CN201410015595 A CN 201410015595A CN 104601015 B CN104601015 B CN 104601015B
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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
- H02M7/2173—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 biphase or polyphase circuit arrangement
-
- 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
- H02M3/33507—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 with automatic control of the output voltage or current, e.g. flyback converters
- H02M3/33523—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 with automatic control of the output voltage or current, e.g. flyback converters with galvanic isolation between input and output of both the power stage and the feedback loop
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Dc-Dc Converters (AREA)
- Rectifiers (AREA)
Abstract
The invention discloses a kind of inverse-excitation type AC DC converters, it adds line voltage detecting and compensating module in AC DC control chips, the line voltage is detected with compensating module by detecting line voltage indirectly, produce a compensation rate for changing with line voltage and changing, the compensation rate is superimposed in feedback signal, line voltage is bigger, the compensation rate that then superposition is got on is also bigger, feedback signal so after line voltage compensation, control and linear adjustment frequency reducing are gone again, so that starting the load point and frequency reducing slope of a curve of frequency reducing in the range of wide input line voltage（85‑264V）All almost it is consistent, so as to while conversion efficiency is improved, obtain optimal electromagnetic interference performance.
Description
Technical field
The present invention relates to switch power technology field, more particularly to a kind of inverse-excitation type AC-DC converter.
Background technology
AC-DC (AC-DC) converter is widely used in nearly all electronic equipment.Existing AC-DC conversions
Device applies traditional AC-DC control chips, and traditional AC-DC control chips are all to drive output to control outside by totem
The break-make of power switch pipe.In order to improve the work(that linear frequency reducing is all added in conversion efficiency, AC-DC control chips of new generation
Can, i.e., with output end load reduction to a certain extent (such as semi-load), frequency can be begun to decline from the 65KHz of full load, and
Linear with power output, power output is smaller, and frequency drops lower, so that switching loss is greatly reduced, improves conversion
Efficiency.In order to not make frequency drop in audiorange (i.e. 20Hz~20KHz), the lower-frequency limit of linear frequency reducing is general in 20KHz
More than.
The control signal of linear frequency reducing is generally feedback (FeedBack, FB) pin of AC-DC control chips at present, because
The voltage of feedback pin directly reflects the size of load, when load by heavy duty gradually excessively to underloading when, the electricity of feedback pin
Pressure also can pass through internal pulses width modulated (PWM) comparator and primary current detection signal by high gradually step-down, feedback signal
It is compared so that primary side peak point current diminishes during each cycle primary side conducting, so as to reduce the transmission of energy；Therefore to control
For AC-DC control chips, feedback pin can detect pin directly as load, for controlling linear frequency reducing.
Referring to Fig. 1, it is the schematic diagram of a traditional inverse-excitation type AC-DC converter.Wherein, AC-DC control chips
104 include feedback signal input terminal a FB, primary side peak point current sense terminal CS, an energization pins VCC, and a ground draws
A pin GND and output end OUT.Output end OUT exports the control letter of suitable duty ratio according to the voltage swing of feedback signal
Number VG, with driving switch pipe Q100.A switching tube Q100 termination primary current detecting resistance R100, another termination transformer
106 primary side NPSame Name of Ends, the primary side N of transformer 106PAnother termination rectification after line voltage.The secondary N of transformer 106S
Incoming end 108 is loaded by commutation diode D200 and electric capacity C300 connections.Transformer 106 is also comprising an assists winding NA,
It is that AC-DC control chips 104 are powered by another commutation diode D100 and electric capacity C200.Inverse-excitation type AC-DC is changed
The load incoming end 108 of device passes through divider resistance R300, R400 and optocoupler device VL100, operational amplifier U100 and resistance
R200 produces the feedback signal input terminal FB for feeding back signal to AC-DC control chips 104.The output end of AC-DC control chips 104
OUT is used for driving switch pipe Q100.
When the systems are operating normally, by secondary NSDivider resistance R300, R400 and optocoupler device VL100, computing put
The feedback unit of big device U100 and resistance R200 compositions can be loaded on incoming end 108 according to the inverse-excitation type AC-DC converter and loaded
Size, produce feedback signal, the feedback signal passes through pwm comparator 202 and primary side NPPeak point current detecting letter
Number compare, for controlling each cycle primary side NPThe size of peak point current；When the inverse-excitation type AC-DC converter loads incoming end
When loading larger on 108, the voltage of feedback signal is higher, and each cycle peak current detection signal is also higher, i.e. primary side NPPeak
It is worth electric current higher；When load reduction on inverse-excitation type AC-DC converter load incoming end 108, the voltage of feedback signal also drops
It is low, each cycle primary side NPPeak point current also declines therewith, and system ensures the balance that energy is transmitted by such feedback, and then
The inverse-excitation type AC-DC converter is maintained to load the stabilization of output voltage on incoming end 108.System is reduced during in order in, underloading
Switching loss, improve conversion efficiency, AC-DC control chips 104 go modulating frequency according to the size of the voltage of feedback signal.
When load incoming end 108 on load reduction to a certain extent when (such as semi-load), the voltage of feedback signal, which drops to, to be set
Fixed threshold value Vth1, now working frequency begun to decline by normal 65KHz；When load further reduction on load incoming end 108
To, (such as fully loaded 10%), the voltage of feedback signal drops to the threshold value V of setting during a lower degreeth2, now work frequency
Rate is preferably minimized value 22KHz；This back loading further decreases up to zero load, and working frequency maintains 22KHz, AC-DC controls always
Chip can enter skip cycle mode (Burst Mode).
Under identical feedback signal, although line voltage is different, AC-DC control chips 104 are detecting identical primary side
Cut-off signals can be sent after peak point current, there is intrinsic shut-off delay t yet with systemdSo that AC-DC control chips 104
Send after cut-off signals, primary side NPStill it may proceed to turn on tdTime, during this period of time primary side peak point current may proceed to
(Vin/Lp) slope rise, VinFor the line voltage after rectification, LpFor the primary side sensibility reciprocal of transformer, in identical time tdIt is interior, line
Voltage is higher, and primary side true peak electric current is higher, to secondary NSThe energy of transmission is bigger, i.e., under identical feedback signal,
Line voltage is higher, loads bigger.If system works in continuous mode (CCM) in addition, under identical primary side peak point current,
Line voltage is higher, primary side NPON time is shorter, secondary NSDischarge time is longer, and the energy of transmission is more, also results in identical
Feedback signal under, line voltage is higher, load it is bigger；The problem of this can bring one seriously, i.e., when on-Line Voltage is relatively low, it is assumed that
FB=Vth1, corresponding is semi-load, then under the line voltage, when load reduction is to semi-load, and system will start to reduce work
Frequency；And on-Line Voltage it is very high when, FB=Vth1Corresponding load can be significantly larger than semi-load, even up to be fully loaded with, then online electricity
When pressure is higher, system will start to reduce working frequency in full load, and this can have a strong impact on the Conducted Electromagnetic Interference of system
(Electro Magnetic Interference, EMI), makes its performance become very poor, it is impossible to meets and requires.
Therefore, the prior art is defective, it is necessary to improve.
The content of the invention
The technical problems to be solved by the invention are：A kind of inverse-excitation type AC-DC converter is provided, to solve in the prior art
AC-DC control chips go modulating frequency according to the size of the voltage of feedback signal, can have a strong impact on the Conducted Electromagnetic Interference of system,
The problem of making its degradation.
Technical scheme is as follows：The present invention provides a kind of inverse-excitation type AC-DC converter, including：Alternating current is inputted
End, rectification unit, transformer, the first to the second diode, AC-DC control chips, feedback module, the first transistor and load
Incoming end, the AC-DC control chips have power pins, control output pin, detection signal input pin, feedback pin with
And ground connection wire pin, the rectification unit with it is described exchange electrical input electric connection, the transformer respectively with the rectification
Unit, one end of the first diode, one end of the second diode, the first transistor and load incoming end are electrically connected with, and described the
The other end of two diodes is electrically connected with the load incoming end, and the power pins and the other end of the first diode are electrical
Connection, it is described control output pin, detection signal input pin respectively with the first transistor be electrically connected with, the feedback pin with
Feedback module be electrically connected with, the feedback module also with it is described load incoming end be electrically connected with, the rectification unit, transformer,
Ground connection wire pin, feedback module and the first transistor of AC-DC control chips are electrically connected with ground wire；
The AC-DC control chips include：Under-voltage protective module, built-in power module, reference voltage module, driving output
Module, Logic control module, oscillator, overcurrent protection, overvoltage protection, PWM comparators, lead-edge-blanking module and line voltage are detectd
Survey and compensating module, the under-voltage protective module is electrically connected with built-in power module with power pins, the built-in power supply
Module is also electrically connected with the reference voltage module, and the reference voltage module is also electric with overcurrent protection and overvoltage protection respectively
Property connection, the lead-edge-blanking module respectively with detection signal input pin, overcurrent protection and PWM comparators be electrically connected with, institute
State PWM comparators, overvoltage protection and line voltage detecting to be electrically connected with feedback pin with compensating module, the line voltage
Detecting with compensating module also respectively with the oscillator, control output pin, built-in power module, the second diode the other end
And detection signal input pin be electrically connected with, the Logic control module respectively with oscillator, overvoltage protection, PWM comparators, mistake
Stream protection and driving output module are electrically connected with, and the driving output module is also electrically connected with the control output pin.
The inverse-excitation type AC-DC converter also includes：First resistor and the first to the 3rd electric capacity；The first resistor one
End is electrically connected with the first transistor, detection signal input pin respectively, and the other end is electrically connected with ground wire；First electric capacity
One end is electrically connected with rectification unit, and the other end is electrically connected with ground wire；Described second electric capacity one end electrically connects with power pins
Connect, the other end is electrically connected with ground wire；3rd electric capacity is connected in parallel with load incoming end.
The transformer includes：Primary side, vice-side winding and assists winding, the vice-side winding are used for powering load,
The assists winding is used to power to AC-DC control chips.
The feedback module includes optocoupler, the first operational amplifier and the second to the 4th resistance；The second resistance
One end and the other end, the load incoming end of the second diode are electrically connected with, and the other end is electrically connected with optocoupler；Described 3rd
Resistance one end and the other end, the load incoming end of the second diode are electrically connected with, and one end of the other end and the 4th resistance electrically connects
Connect, the other end and the load incoming end of the 4th resistance are electrically connected with；First operational amplifier respectively with the 4th resistance
One end, the other end of the 4th resistance and optocoupler be electrically connected with；The optocoupler is also electric with feedback pin, ground wire respectively
Property connection.
The first transistor has first grid, the first drain electrode and the first source electrode, the first grid and the control
Output pin processed is electrically connected with, and first source electrode is electrically connected with transformer, first drain electrode respectively with first resistor
One end and detection signal input pin are electrically connected with.
The line voltage detecting includes with compensating module：Sampled signal generation module, first switch, second switch, second
Operational amplifier, the 3rd operational amplifier, second transistor, third transistor, the 5th resistance and the 6th resistance, described second
Operational amplifier has the first positive input pin, the first negative input pin and the first output pin, the 3rd operation amplifier
Utensil has the second positive input pin, the second negative input pin and the second output pin, and the second transistor has second gate
Pole, the second drain electrode and the second source electrode, the third transistor have the 3rd grid, the 3rd drain electrode and the 3rd source electrode, described
Sampled signal generation module is electrically connected with control output pin, first switch and second switch respectively, and the first switch is also
It is electrically connected with respectively with the detection signal input pin, one end of the 4th electric capacity, the first negative input pin, the second switch
Also it is electrically connected with respectively with detection signal input pin, one end of the 5th electric capacity, the second positive input pin, first positive input
One end of pin and the 5th resistance, the second drain electrode are electrically connected with, the other end and the second negative input pin of the 5th resistance, the
Two output pins are electrically connected with, and first output pin is electrically connected with second, third grid, second source electrode, the 3rd
Source electrode is electrically connected with built-in power module, and the 3rd drain electrode and one end of oscillator, the 6th resistance are electrically connected with, described
The other end of 6th resistance is electrically connected with feedback pin, the other end of the 4th electric capacity, the other end of the 5th electric capacity with
Ground wire is electrically connected with.
Using such scheme, inverse-excitation type AC-DC converter of the invention is detectd by the line voltage to linear frequency reducing
Survey, be superimposed on producing a compensation rate for changing and changing with line voltage on FB signals so that in wide input voltage range
(85-264V), the slope of load point and frequency reducing curve (F-Po) that system initially enters frequency reducing all keeps identical, so as to improve
While conversion efficiency, optimal electromagnetic interference performance is obtained.
Brief description of the drawings
Fig. 1 is the schematic diagram of traditional inverse-excitation type AC-DC converter.
Fig. 2 is the schematic diagram of inverse-excitation type AC-DC converter of the present invention.
Fig. 3 is that neutral voltage of the present invention is detected and compensating module and its circuit diagram of annexation.
Fig. 4 is sampled signal S1, S2 and peak point current detection signal CS oscillogram in the present invention.
Embodiment
Below in conjunction with the drawings and specific embodiments, the present invention is described in detail.
Referring to Fig. 2, the present invention provides a kind of inverse-excitation type AC-DC converter, in order to improve the performance of linear frequency reducing, make it
Do not change with line voltage (being obtained after rectification unit rectification) and change, to obtain optimal systematic function, the present invention is in AC-DC controls
Line voltage detecting and compensating module 61 are added in coremaking 60, line voltage detecting is with compensating module 61 by detecting indirectly
Line voltage, produces a compensation rate for changing with line voltage and changing, and the compensation rate is superimposed in feedback signal, and line voltage is got over
Greatly, then the compensation rate that the superposition is got on is also bigger, the feedback signal so after line voltage compensation, then goes control and regulation line
Property frequency reducing so that start frequency reducing load point and frequency reducing slope of a curve (85-264V) in the range of wide input line voltage
All almost it is consistent, so as to while conversion efficiency is improved, obtain optimal electromagnetic interference performance.
The inverse-excitation type AC-DC converter includes：Exchange electrical input 52, rectification unit 54, transformer 56, the first to the second
Diode D1, D2, AC-DC control chip 60, feedback module 58, the first transistor Q1 and load incoming end 59, the AC-DC
Control chip 60 has power pins Vcc, control output pin OUT, detection signal input pin CS, feedback pin FB and connect
Ground wire pin, the rectification unit 54 is electrically connected with the electrical input 52 that exchanges, the transformer 56 respectively with it is described whole
Flow unit 54, the first diode D1 one end, the second diode D2 one end, the first transistor Q1 and the electricity of load incoming end 59
Property connection, the other end of the second diode D2 with it is described load incoming end 59 be electrically connected with, the power pins VccWith
The one diode D1 other end is electrically connected with, and the control output pin OUT, detection signal input pin CS are brilliant with first respectively
Body pipe Q1 is electrically connected with, and the feedback pin FB is electrically connected with feedback module 58, the feedback module 58 also with the load
Incoming end 59, the second diode D2 other end are electrically connected with, the rectification unit 54, transformer 56, AC-DC control chips 60
Ground connection wire pin, feedback module 58 and the first transistor Q1 with ground wire be electrically connected with.
The AC-DC control chips 60 include：Under-voltage protective module 61, built-in power module 62, reference voltage module 63,
Drive output module 64, Logic control module 65, oscillator 66, overcurrent protection 67, overvoltage protection 68, PWM comparators 69, forward position
Blanking module 71 and line voltage detecting and compensating module 72, the under-voltage protective module 61 and built-in power module 62 with electricity
Source pin VccIt is electrically connected with, the built-in power module 62 is also electrically connected with the reference voltage module 63, the benchmark electricity
Die block 63 is also electrically connected with overcurrent protection 67 and overvoltage protection 68 respectively, and the lead-edge-blanking module 71 is believed with detecting respectively
Number input pin CS, overcurrent protection 67 and PWM comparators 69 are electrically connected with, the PWM comparators 69, overvoltage protection 68 and
Line voltage is detected to be electrically connected with compensating module 72 with feedback pin FB, and the line voltage detecting is also distinguished with compensating module 72
It is electrically connected with the oscillator 66, control output pin OUT, built-in power module 62 and detection signal input pin CS, institute
State Logic control module 65 and export mould with oscillator 66, overvoltage protection 68, PWM comparators 69, overcurrent protection 67 and driving respectively
Block 64 is electrically connected with, and the driving output module 64 is also electrically connected with the control output pin OUT.
The inverse-excitation type AC-DC converter also includes：First resistor R1 and first to the 3rd electric capacity C1, C2, C3；It is described
First resistor R1 one end is electrically connected with the first transistor Q1, detection signal input pin CS respectively, and the other end is electrical with ground wire
Connection；Described first electric capacity C1 one end is electrically connected with rectification unit 54, and the other end is electrically connected with ground wire；Second electric capacity
C2 one end and power pins VccIt is electrically connected with, the other end is electrically connected with ground wire；The 3rd electric capacity C3 and load incoming end 59
It is connected in parallel.
The transformer 56 includes：Primary side NP, vice-side winding NSAnd assists winding NA, the vice-side winding NSFor to
Load supplying, the assists winding NAFor being powered to AC-DC control chips 60.
The feedback module 58 include optocoupler VL, the first operational amplifier U and the second to the 4th resistance R2, R3,
R4；Described second resistance R2 one end and the second diode D2, load incoming end 59 other end are electrically connected with, the other end and optocoupler
Device VL is electrically connected with；Described 3rd resistor R3 one end and the second diode D2, load incoming end 59 are electrically connected with, the other end with
4th resistance R4 one end is electrically connected with, and the other end and the load incoming end 59 of the 4th resistance R4 are electrically connected with；Described
One operational amplifier U is electrically connected with the 4th resistance R4 one end, the 4th resistance R4 other end and optocoupler VL respectively；Institute
Optocoupler VL is stated also to be electrically connected with feedback pin FB, ground wire respectively.
The first transistor Q1 has first grid g1, the first drain electrode d1 and the first source electrode s1, the first grid
G1 is electrically connected with the control output pin OUT, and the first source electrode s1 is electrically connected with transformer 56, first drain electrode
D1 is electrically connected with first resistor R1 one end and detection signal input pin CS respectively.
Fig. 3 and Fig. 4 is referred to, the line voltage detecting includes with compensating module 72：Sampled signal generation module 82, first
Switch K1, second switch K2, the second operational amplifier EA1, the 3rd operational amplifier EA2, second transistor Q2, third transistor
Q3, the 5th resistance R5 and the 6th resistance R6, the second operational amplifier EA1 have the first positive input pin+, it is first negative defeated
Enter pin-and the first output pin, the 3rd operational amplifier EA2 have the second positive input pin+, the second negative input draws
Pin-and the second output pin, the second transistor Q2 have second grid g2, the second drain electrode d2 and the second source electrode s2,
The third transistor Q3 has the 3rd grid g3, the 3rd drain electrode d3 and the 3rd source electrode s3, the sampled signal generation module
82 are electrically connected with control output pin OUT, first switch K1 and second switch K2 respectively, and the first switch K1 also distinguishes
Opened with the detection signal input pin CS, the 4th electric capacity C4 one end, the first negative input pin-electric connection, described second
Close K2 also respectively with detection signal input pin CS, the 5th electric capacity C5 one end, the second positive input pin+electric connection, it is described
First positive input pin+be electrically connected with the 5th resistance R5 one end, the second drain electrode d2, the other end of the 5th resistance R5 with
Second negative input pin-, the second output pin be electrically connected with, first output pin and second, third grid g2, g3 are electrical
Connection, the second source electrode s2, the 3rd source electrode s3 are electrically connected with built-in power module 62, the 3rd drain electrode d3 and vibration
Device 66, the 6th resistance R6 one end are electrically connected with, and the other end and the feedback pin FB of the 6th resistance R6 are electrically connected with, described
The 4th electric capacity C4 other end, the 5th electric capacity C5 other end are electrically connected with ground wire.The sampled signal generation module 82
The sampled signal S1 and S2 of output are respectively used to control first switch K1 and second switch K2.The 3rd of the third transistor Q3
D3 drain as line voltage detecting and the output of compensating module 72, for controlling oscillator 66, to realize linear frequency reducing.
The delayed t of control signal that the sampled signal generation module 82 is used on control output pin OUTLEBAfter time
The sampled signal S1 of narrower in width is produced, and sampled signal is sent after time delay Δ t fixed after sampled signal S1 is sent
S2, tLEBTime is used to filter out primary side NPThe spike burr of firm start-up time peak point current detection signal (CS), in order to guarantee to adopt
Sample to primary side turn on when peak point current detection signal voltage, sampled signal S1 and S2 must be set in AC-DC control chips 60
Fixed primary side NPSent in most short ON time.Two such sampled signal only poor CS2-CS1=[(Vin/Lp)*Δt]/Rcs, its
Middle VinFor the line voltage after rectification, LpFor the primary side sensibility reciprocal of transformer, RcsFor current sense first resistor R1 resistance.Then flow through
5th resistance R5 electric current, which is equal to, flows through second transistor Q2 electric current, its current value I0=(CS2-CS1)/R1, then I1=K*
I0=K* (CS2-CS1)/R1, then FB1=FB+K*I0=FB+K* (CS2-CS1) * R2/R1=FB+ [K* (Vin/Lp)*Δt*
R2]/(R1*Rcs).In the description of background technology it is known that under identical load, line voltage VinIt is higher, feedback signal
Voltage it is smaller, and superposition here [K* (Vin/Lp)*Δt*R2]/(R1*Rcs) with line voltage VinIncrease and increase, because
This is by the reasonable design to K and R1, R2, and we can keep FB1 not with line voltage V under identical loadinChange and
Change, then controls the starting point and slope of linear frequency reducing, to realize in wide input voltage with the signal (FB1) compensated
In the range of (85-264V), the slope of load point and frequency reducing curve (F-Po) that system initially enters frequency reducing all keeps identical so that
While conversion efficiency is improved, optimal electromagnetic interference performance is obtained.
In summary, the present invention provides a kind of inverse-excitation type AC-DC converter, is detectd by the line voltage to linear frequency reducing
Survey, be superimposed on producing a compensation rate for changing and changing with line voltage on FB signals so that in wide input voltage range
(85-264V), the slope of load point and frequency reducing curve (F-Po) that system initially enters frequency reducing all keeps identical, so as to improve
While conversion efficiency, optimal electromagnetic interference performance is obtained.
These are only presently preferred embodiments of the present invention, be not intended to limit the invention, it is all the present invention spirit and
Any modifications, equivalent substitutions and improvements made within principle etc., should be included in the scope of the protection.
Claims (5)
1. a kind of inverse-excitation type AC-DC converter, it is characterised in that including：Exchange electrical input, rectification unit, transformer, first
To the second diode, AC-DC control chips, feedback module, the first transistor and load incoming end, the AC-DC controls core
Piece has power pins, control output pin, detection signal input pin, feedback pin and ground connection wire pin, the rectification
Unit with it is described exchange electrical input be electrically connected with, the transformer respectively with the rectification unit, one end of the first diode,
One end of second diode, the first transistor and load incoming end are electrically connected with, the other end of second diode with it is described
Load incoming end to be electrically connected with, the power pins and the other end of the first diode are electrically connected with, the control output pin,
Detection signal input pin is electrically connected with the first transistor respectively, and the feedback pin is electrically connected with feedback module, described
Feedback module is also electrically connected with the load incoming end, the rectification unit, transformer, the ground wire of AC-DC control chips
Pin, feedback module and the first transistor are electrically connected with ground wire；
The AC-DC control chips include：Under-voltage protective module, built-in power module, reference voltage module, driving output mould
Block, Logic control module, oscillator, overcurrent protection, overvoltage protection, PWM comparators, lead-edge-blanking module and line voltage detecting
With compensating module, the under-voltage protective module is electrically connected with built-in power module with power pins, the built-in power supply mould
Block is also electrically connected with the reference voltage module, and the reference voltage module is also electrical with overcurrent protection and overvoltage protection respectively
Connection, the lead-edge-blanking module is electrically connected with detection signal input pin, overcurrent protection and PWM comparators respectively, described
PWM comparators, overvoltage protection and line voltage detecting are electrically connected with compensating module with feedback pin, and the line voltage is detectd
Survey with compensating module also respectively with the oscillator, control output pin, built-in power module, the other end of the second diode and
Detection signal input pin be electrically connected with, the Logic control module respectively with oscillator, overvoltage protection, PWM comparators, excessively stream
Protection and driving output module are electrically connected with, and the driving output module is also electrically connected with the control output pin；
The line voltage detecting includes with compensating module：Sampled signal generation module, first switch, second switch, the second computing
Amplifier, the 3rd operational amplifier, second transistor, third transistor, the 5th resistance and the 6th resistance, second computing
Amplifier has the first positive input pin, the first negative input pin and the first output pin, the 3rd operation amplifier utensil
There are the second positive input pin, the second negative input pin and the second output pin, the second transistor has second grid,
Two drain electrodes and the second source electrode, the third transistor have the 3rd grid, the 3rd drain electrode and the 3rd source electrode, the sampling letter
Number generation module is electrically connected with control output pin, first switch and second switch respectively, the first switch also respectively with
The detection signal input pin, one end of the 4th electric capacity, the first negative input pin are electrically connected with, and the second switch is also distinguished
With detection signal input pin, one end of the 5th electric capacity, the second positive input pin be electrically connected with, the first positive input pin with
One end of 5th resistance, the second drain electrode are electrically connected with, the other end and the second negative input pin of the 5th resistance, the second output
Pin is electrically connected with, and first output pin is electrically connected with second, third grid, and second source electrode, the 3rd source electrode are equal
It is electrically connected with built-in power module, the 3rd drain electrode and one end of oscillator, the 6th resistance are electrically connected with, the 6th electricity
The other end of resistance is electrically connected with feedback pin, and the other end of the 4th electric capacity, the other end of the 5th electric capacity are electric with ground wire
Property connection.
2. inverse-excitation type AC-DC converter according to claim 1, it is characterised in that also include：First resistor and first
To the 3rd electric capacity；Described first resistor one end respectively with the first transistor, detection signal input pin be electrically connected with, the other end with
Ground wire is electrically connected with；Described first electric capacity one end is electrically connected with rectification unit, and the other end is electrically connected with ground wire；Described second
Electric capacity one end is electrically connected with power pins, and the other end is electrically connected with ground wire；3rd electric capacity is in parallel with load incoming end
Connection.
3. inverse-excitation type AC-DC converter according to claim 1, it is characterised in that the transformer includes：Primary side, pair
Side winding and assists winding, the vice-side winding are used for powering load, and the assists winding is used to give AC-DC control chips
Power supply.
4. inverse-excitation type AC-DC converter according to claim 1, it is characterised in that the feedback module includes optical coupler
Part, the first operational amplifier and the second to the 4th resistance；The other end of described second resistance one end and the second diode, load
Incoming end is electrically connected with, and the other end is electrically connected with optocoupler；The other end of described 3rd resistor one end and the second diode,
Load incoming end to be electrically connected with, one end of the other end and the 4th resistance is electrically connected with, the other end of the 4th resistance and load
Incoming end is electrically connected with；First operational amplifier one end respectively with the 4th resistance, the other end and optocoupler of the 4th resistance
Device electric is connected；The optocoupler is also electrically connected with feedback pin, ground wire respectively.
5. inverse-excitation type AC-DC converter according to claim 2, it is characterised in that the first transistor has first
Grid, the first drain electrode and the first source electrode, the first grid are electrically connected with the control output pin, first source electrode
It is electrically connected with transformer, first drain electrode is electrically connected with one end of first resistor and detection signal input pin respectively.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201410015595.8A CN104601015B (en) | 2014-01-14 | 2014-01-14 | Inverse-excitation type AC DC converters |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410015595.8A CN104601015B (en) | 2014-01-14 | 2014-01-14 | Inverse-excitation type AC DC converters |
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| CN104601015A CN104601015A (en) | 2015-05-06 |
| CN104601015B true CN104601015B (en) | 2017-08-11 |
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| CN106941321B (en) * | 2017-03-22 | 2019-02-01 | 深圳市稳先微电子有限公司 | A kind of control circuit of synchronous rectifier |
| CN108449070A (en) * | 2018-03-15 | 2018-08-24 | 南京邮电大学 | Self-adapting load variation adjusts the AC-DC pierce circuits of frequency |
| CN112290812B (en) * | 2020-10-26 | 2021-11-16 | 深圳市稳先微电子有限公司 | AC-DC control chip and AC-DC flyback controller |
| CN112803773B (en) * | 2021-01-28 | 2022-06-28 | 深圳市稳先微电子有限公司 | Control method of PSR flyback switching power supply, secondary side controller device and switching power supply |
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| KR100235104B1 (en) * | 1996-07-24 | 1999-12-15 | 전주범 | A circuit of controlling a horizontal linearity in a multi-mode monitor |
| CN201438266U (en) * | 2009-07-22 | 2010-04-14 | Bcd半导体制造有限公司 | Pulse modulation controller |
| CN101651411A (en) * | 2009-09-15 | 2010-02-17 | 上海导向微电子有限公司 | Frequency jittering system and frequency jittering method |
| CN203660911U (en) * | 2014-01-14 | 2014-06-18 | 深圳市稳先微电子有限公司 | Flyback AC-DC converter |
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