CN106549581B - The control circuit of flyback power supply converter - Google Patents
The control circuit of flyback power supply converter Download PDFInfo
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- CN106549581B CN106549581B CN201510595843.5A CN201510595843A CN106549581B CN 106549581 B CN106549581 B CN 106549581B CN 201510595843 A CN201510595843 A CN 201510595843A CN 106549581 B CN106549581 B CN 106549581B
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Abstract
The present invention proposes a kind of control circuit of power adapter.Power adapter includes first siding ring, second siding ring, power switch and photo-coupler.Input signal is converted to output signal to control energy-sensitive and conversion between first siding ring and second siding ring by the handover operation of power switch.Photo-coupler is used to the signal of the secondary side of power adapter feeding back to primary side.Control circuit includes: feedback pin, and the signal for feeding back to primary side according to photo-coupler provides feedback voltage；Signal generating circuit is controlled, feedback pin is coupled to, is arranged to generate control signal according to feedback voltage, to control the turn-on time of power switch；Clamp voltage generation circuit is arranged to generate clamp voltage；And electric current clamped circuit, it is arranged to flow to the upper limit value of the output electric current of the photo-coupler from the feedback pin according to the clamp voltage strangulation.Whereby, the output current that photo-coupler is flowed to from feedback pin can be reduced.
Description
Technical field
The related flyback power supply converter of the present invention (flyback power converter), it is espespecially a kind of for that can drop
The control circuit of the power consumption of low flyback power supply converter in standby mode.
Background technique
Flyback power supply converter is used to convert input voltage into the direct current stablized, be isolated, to supply the negative of rear class
It carries and uses, application range is quite extensive.According to the difference of feedback compensation mechanism, flyback power supply converter divides into use again
Primary side corrects the framework of (primary side regulation, PSR), and corrects (secondary using secondary side
Side regulation, SSR) framework.
In the flyback power supply converter using secondary side correction framework, need to utilize photo-coupler
(optocoupler) signal of secondary side is fed back into a lateral circuit, enables the control circuit of primary side according to optical coupling
The signal that device is fed back adjusts the turn-on time of power switch, to ensure that secondary side can continue the stable output voltage of output.
Control circuit can be coupled to photo-coupler using a feedback pin.It is well known that when flyback power supply converter into
When entering standby mode, the equivalent resistance of photo-coupler can be reduced, and lead to the electric current for flowing to photo-coupler from feedback pin at this time
Amount increases.Therefore, conventional control circuit most important power consumption in standby mode is that Zhao Yin is flowed in from feedback pin
The current drain of photo-coupler.
Summary of the invention
In view of this, the power consumption of control circuit in standby mode how is effectively reduced, to save flyback power supply
The whole power consumption of converter, actually industry problem to be solved.
This specification provides a kind of embodiment of the control circuit of flyback power supply converter.The flyback power supply converter
Include a first siding ring, a second siding ring, a power switch and a photo-coupler, the handover operation of the power switch
To control energy-sensitive and conversion between the first siding ring and the second siding ring, an input signal is converted to one
Output signal, and the photo-coupler is used to the signal of the secondary side of the flyback power supply converter feeding back to the flyback power supply
The primary side of converter.The control circuit includes: a feedback pin, for coupling the photo-coupler, and according to the photo-coupler
The signal for feeding back to primary side provides a feedback voltage；One control signal generating circuit, be coupled to the feedback pin, be arranged to according to
A control signal is generated according to the feedback voltage, to control the turn-on time of the power switch；One clamp voltage generation circuit, setting
At generating a clamp voltage；And an electric current clamped circuit, it is coupled to the feedback pin and the clamp voltage generation circuit, is arranged
At the upper limit value for the output electric current for flowing to the photo-coupler from the feedback pin according to the clamp voltage strangulation.
One of the advantages of above-described embodiment is the upper limit value quilt that the feedback pin is flowed to the output electric current of the photo-coupler
Strangulation can effectively reduce the power consumption of control circuit in a preset value, and then save the whole consumption of flyback power supply converter
Electricity.
One of the advantages of above-described embodiment is that the output electric current for flowing to the photo-coupler from the feedback pin can be made anti-with this
The characteristic relation of feedthrough voltage between the two, present have successional smooth relationship, break down to avoid the control circuit or
Operate unstable problem.
Other advantages of the invention will be by following explanation and drawings provide more detailed explanation.
Detailed description of the invention
The drawings described herein are used to provide a further understanding of the present application, constitutes part of this application, this Shen
Illustrative embodiments and their description please are not constituted an undue limitation on the present application for explaining the application.
Fig. 1 is the simplified functional block diagram of flyback power supply converter of one embodiment of the invention.
Fig. 2 is that the characteristic relation between the feedback voltage in the feedback pin of one embodiment of the invention and output electric current simplifies
Schematic diagram afterwards.
[symbol description]
100 flyback power supply converters
101 input capacitances
102 first siding rings
103 second siding rings
104 diodes
105 power switch
106 output capacitances
107 loads
110 photo-couplers
111 photodiodes
113 phototransistors
120 control circuits
121 feedback pins
123 control signal generating circuits
125 clamp voltage generation circuits
127 electric current clamped circuits
131 resistance
133 transistors
135 comparison circuits
137 compensating electric capacities
Specific embodiment
Illustrate the embodiment of the present invention below in conjunction with relevant drawings.In the accompanying drawings, identical label indicate it is identical or
Similar element or method flow.
Fig. 1 is the simplified functional block diagram of flyback power supply converter 100 of one embodiment of the invention.Flyback power supply
Converter 100 includes input capacitance 101,102, second siding ring first siding ring (primary-side coil)
(secondary-side coil) 103, diode 104, power switch 105, output capacitance 106, load 107, photo-coupler
110 and control circuit (control circuit) 120.
In flyback power supply converter 100, input capacitance 101 is for reducing the noise in input signal Vin.Primary side
The first end of coil 102 is coupled to input signal Vin.The first end of second siding ring 103 is for providing output signal Vout.Two
Pole pipe 104 is coupled between the first end of second siding ring 103 and load 107.Power switch 105 is coupled to first siding ring
Between 102 second end and one fixed potential end (for example, ground terminal).The handover operation of power switch 105 is primary to control
Energy-sensitive and conversion between lateral coil 102 and second siding ring 103, are converted to output signal for input signal Vin
Vout.Output capacitance 106 is coupled to the output end of diode 104, to reduce the noise in output signal Vout.Photo-coupler
110 for feeding back to the primary of flyback power supply converter 100 for the signal of the secondary side of flyback power supply converter 100
Side.
In the embodiment in figure 1, photo-coupler 110 mainly includes photodiode (photodiode) 111 and photoelectricity
Transistor (phototransistor) 113.Photodiode 111 can produce and the secondary side of flyback power supply converter 100
The corresponding light of output signal Vout size.Phototransistor 113 is coupled to control circuit 120, for sensing two pole of photoelectricity
The light that pipe 111 generates, to generate corresponding sensing signal.
Control circuit 120 is arranged to control the handover operation of power switch 105, flows through first siding ring 102 with adjustment
The size of electric current IL generates the magnetic field changed in first siding ring 102 whereby.Based on undesirable mutual electromagnetic inductance principle, the magnetic field of the variation
Second siding ring 103 can be made to generate potential difference, and transmit electric current, and then charged to output capacitance 106.Control circuit 120 can root
The turn-on time of power switch 105 is adjusted, according to the signal that photo-coupler 110 is fed back to ensure that it is steady that secondary side can continue output
Fixed output signal Vout.
As shown in Figure 1, control circuit 120 includes feedback pin 121, control signal generating circuit (control
Signal generating circuit) 123, clamp voltage generation circuit (clamp voltage generating
Circuit) 125 and electric current clamped circuit (lower limit clamping circuit) 127.
In control circuit 120, feedback pin 121 is fed back for coupling photo-coupler 110, and according to photo-coupler 110
Signal to primary side provides a feedback voltage V comp.For example, feedback pin 121 can be coupled to the photoelectricity in photo-coupler 110
Transistor 113, and feedback voltage V comp is formed according to the sensing signal of phototransistor 113.Control signal generating circuit 123
It is coupled to feedback pin 121, is arranged to generate control signal CTL according to feedback voltage V comp, to control power switch 105
Turn-on time.Clamp voltage generation circuit (also known as clamping voltag generation circuit) 125 is arranged to generate a fixed strangulation electricity
Press Vclamp.Electric current clamped circuit (also known as current clamp circuit) 127 is coupled to feedback pin 121 and clamp voltage generates electricity
Road 125 is arranged to flow to an output electric current of photo-coupler 110 from feedback pin 121 according to clamp voltage Vclamp strangulation
The upper limit value of Icomp.
In implementation, various known current control modes (current mode) are can be used in control signal generating circuit 123
Or the circuit framework of voltage mode control (voltage mode) is realized.
As previously mentioned, the photoelectric crystal when flyback power supply converter 100 enters standby mode, in photo-coupler 110
The equivalent resistance of pipe 113 can reduce, and cause to flow to the defeated of photo-coupler 110 from the feedback pin 121 of control circuit 120 at this time
Electric current Icomp will increase out.This is also the main electric power Elements Of Expense of control circuit 120 in standby mode.
At this point, electric current clamped circuit 127 in control circuit 120 can will output electric current Icomp strangulation in a preset value, with
The upper limit value for avoiding output electric current Icomp is more than the preset value.
For example, in the embodiment in figure 1, electric current clamped circuit 127 includes resistance 131, transistor 133, comparison circuit
135 and compensating electric capacity 137.Resistance 131 is coupled to reference voltage Vref, determines electricity for generating according to reference voltage Vref
Press (determining voltage) Vic.In running, the output electric current of photo-coupler 110 is flowed to from feedback pin 121
The size of Icomp is by determining that both voltage Vic and the resistance value of resistance 131 are controlled.Since the resistance value of resistance 131 is
Fixed, so determining that voltage Vic determines the size of output electric current Icomp.Transistor 133 is coupled to resistance 131 and feedback
Between pin 121.Comparison circuit 135 is coupled to clamp voltage generation circuit 125, resistance 131 and transistor 133, is arranged to compare
Compared with clamp voltage Vclamp and voltage Vic is determined, to control the control terminal of transistor 133.Compensating electric capacity 137, which is then coupled to, to be compared
The output end of circuit 135 is compensated with the output to comparison circuit 135.In implementation, comparison circuit 135 can be simple with framework
Operational amplifier realize, to simplify the complexity of circuit design.
The collocation of aforementioned transistor 133 and both comparison circuits 135 operates, and meeting dynamic adjustment determines the size of voltage Vic.
Specifically, feedback voltage V comp be greater than clamp voltage Vclamp when, determine voltage Vic size can be configured to instead
Feedthrough voltage Vcomp is identical, and when feedback voltage V comp drops below clamp voltage Vclamp, determines that voltage Vic then can be by
Size of the strangulation in clamp voltage Vclamp.
In other words, determine that the lower limit value of voltage Vic can be clamped at the size of clamp voltage Vclamp.Therefore, even if instead
Feedthrough voltage Vcomp falls below the level of clamp voltage Vclamp, determines that voltage Vic can also be maintained and clamp voltage Vclamp
Identical size declines without will continue to.
Referring to FIG. 2, its depicted feedback voltage V comp and output electric current in feedback pin 121 of the invention
The simplified schematic diagram of an embodiment of the characteristic relation of Icomp between the two.
As shown in Fig. 2, in the case where feedback voltage V comp is greater than clamp voltage Vclamp, due to determining voltage Vic's
Size can be identical as feedback voltage V comp, so line can be presented in the size of both feedback voltage V comp and output electric current Icomp
Property it is related.
On the other hand, in the case where feedback voltage V comp drops below clamp voltage Vclamp, due to clamp voltage
Vclamp is fixed value, and determines that the size of voltage Vic can be identical as clamp voltage Vclamp, so determining that voltage Vic is also
Fixed value by output electric current Icomp size be by determining that voltage Vic and the resistance value of resistance 131 are determined, determining
In the case that constant voltage Vic is clamped at the size of clamp voltage Vclamp, no matter the equivalent resistance of phototransistor 113 drops
As low as what degree, the upper limit value for exporting electric current Icomp can all be clamped at a preset value, up increase without will continue to.Cause
This, when feedback voltage V comp is lower than clamp voltage Vclamp, output electric current Icomp can be the size with feedback voltage V comp
Unrelated definite value.
For example, as shown in Fig. 2, in the case where no electric current clamped circuit 127, the maximum value of output electric current Icomp is
Ia, and in the case where electric current clamped circuit 127 carries out aforementioned running, the upper limit value of output electric current Icomp can be clamped at separately
One lower preset value Ib, without reaching original maximum value Ia.
It is compared with traditional control circuit, since the upper limit value for exporting electric current Icomp of aforementioned control circuit 120 is by strangulation
In lower preset value Ib, therefore the total electricity for flowing to photo-coupler 110 can be reduced.In this way, which control just can be effectively reduced
The power consumption of circuit 120, and then save the whole power consumption of flyback power supply converter 100.
In addition, as shown in Fig. 2, since electric current clamped circuit 127 is the lower limit value strangulation by decision voltage Vic in strangulation
The size of voltage Vclamp, rather than will determine that voltage Vic is switched between different high low potentials using switching circuit, institute
It is closed with flowing to the characteristic of the output electric current Icomp and feedback voltage V comp of photo-coupler 110 between the two from feedback pin 121
System, it will presenting has successional smooth relationship, without the acute variation of discontinuity.In this way, can keep away
Exempt from control circuit 120 and breaks down or operate unstable problem.
In implementation, the electric current clamped circuit 127 in aforementioned control circuit 120 can keep operating at any time, can also only exist
When flyback power supply converter 100 is in standby mode, the upper limit of electric current Icomp is just exported according to clamp voltage Vclamp strangulation
Value.
Different function square in aforementioned flyback power supply converter 100 can realize with different circuits respectively, can also
It is incorporated into a single circuit chip.For example, all function blocks in control circuit 120 may be integrally incorporated to a single control electricity
In road chip (controller IC), further the integration of power switch 105 can also be arranged in control circuit 120, with shape
At a single conversion circuit chip (converter IC).
Some vocabulary is used in specification and claims to censure specific element.However, affiliated technology neck
The technical staff in domain is, it is to be appreciated that same element may be called with different nouns.Specification and claims are simultaneously
In a manner of not using the difference of title as differentiation element, but with the difference of element functionally as the benchmark of differentiation.?
"comprising" mentioned by specification and claims is open term, therefore should be construed to " including but not limited to ".Separately
Outside, " coupling " is herein comprising any direct and indirect connection means.Therefore, if it is described herein that first element is coupled to second yuan
Part, then representing first element can be directly connected by being electrically connected or being wirelessly transferred, and the signals connection type such as optical delivery
In second element, or by other elements or connection means, electrical property or signal are connected to the second element indirectly.
It is used herein " and/or " describing mode, any group comprising one of cited or multiple projects
It closes.In addition, unless specified in the instructions, otherwise the term of any singular lattice all includes the connotation of multiple grid simultaneously.
Voltage signal in specification and claims, can be used voltage form on the implementation or current forms are come in fact
It is existing.Current signal in specification and claims, also voltage available form or current forms are realized on the implementation.
The foregoing is merely a prefered embodiment of the invention, all equivalent changes and modifications done according to the claims in the present invention, all
It should belong to the scope of the present invention.
Claims (5)
1. a kind of control circuit (120) of flyback power supply converter (100), which includes one
First siding ring (102), a second siding ring (103), a power switch (105) and a photo-coupler (110), the power
The handover operation of (105) is switched to control the energy-sensitive between the first siding ring (102) and the second siding ring (103)
And conversion, an input signal (Vin) is converted to an output signal (Vout), and the photo-coupler (110) is used for this instead
The signal of the secondary side of excitation power supply converter (100) feeds back to the primary side of the flyback power supply converter (100), feature
It is, which includes:
One feedback pin (121) feeds back to primary side for coupling the photo-coupler (110), and according to the photo-coupler (110)
Signal provide a feedback voltage (Vcomp)；
One control signal generating circuit (123), is coupled to the feedback pin (121), is arranged to according to the feedback voltage (Vcomp)
Control signal (CTL) is generated, to control the turn-on time of the power switch (105)；
One clamp voltage generation circuit (125) is arranged to generate a clamp voltage (Vclamp)；And
One electric current clamped circuit (127) is coupled to the feedback pin (121) and the clamp voltage generation circuit (125), is arranged to
An output electric current of the photo-coupler (110) is flowed to from the feedback pin (121) according to clamp voltage (Vclamp) strangulation
(Icomp) upper limit value；
Wherein, which includes:
One resistance (131) is coupled to a reference voltage (Vref), determines voltage for generating one according to the reference voltage (Vref)
(Vic), to determine the size of the output electric current (Icomp)；
One transistor (133) is coupled between the resistance (131) and the feedback pin (121)；And
One comparison circuit (135) is coupled to the clamp voltage generation circuit (125), the resistance (131) and the transistor
(133), it is arranged to compare the clamp voltage (Vclamp) and the decision voltage (Vic), to control a control of the transistor (133)
End processed so that the feedback voltage (Vcomp) be greater than clamp voltage (Vclamp) when, the size of the decision voltage (Vic) with
The feedback voltage (Vcomp) is identical, and when the feedback voltage (Vcomp) is less than clamp voltage (Vclamp), decision electricity
Pressure (Vic) is clamped at the size of the clamp voltage (Vclamp), whereby by the upper limit value strangulation of the output electric current (Icomp)
In a preset value.
2. control circuit (120) as described in claim 1, which is characterized in that the electric current clamped circuit (127) has additionally comprised:
One compensating electric capacity (137) is coupled to the output end of the comparison circuit (135).
3. control circuit (120) as described in claim 1, which is characterized in that the comparison circuit (135) is an operation amplifier
Device.
4. control circuit (120) as described in claim 1, which is characterized in that the electric current clamped circuit (127) is only anti-at this
When excitation power supply converter (100) is in standby mode, just according to clamp voltage (Vclamp) strangulation output electric current
(Icomp) upper limit value.
5. control circuit (120) as described in claim 1, which is characterized in that the power switch (105) is set to control electricity
In road (120).
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| Application Number | Priority Date | Filing Date | Title |
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| CN201510595843.5A CN106549581B (en) | 2015-09-18 | 2015-09-18 | The control circuit of flyback power supply converter |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510595843.5A CN106549581B (en) | 2015-09-18 | 2015-09-18 | The control circuit of flyback power supply converter |
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| CN106549581A CN106549581A (en) | 2017-03-29 |
| CN106549581B true CN106549581B (en) | 2019-03-12 |
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| EP3826166A1 (en) | 2019-11-25 | 2021-05-26 | Carrier Corporation | Power module and converter with asymmetrical semiconductor rating arrangement |
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|---|---|---|---|---|
| CN1937383A (en) * | 2005-09-22 | 2007-03-28 | 松下电器产业株式会社 | Switch power supply, semiconductor appatatus and controlling method |
| CN101997534A (en) * | 2009-08-13 | 2011-03-30 | 立锜科技股份有限公司 | Feedback circuit and control method for isolated power converter |
| CN203057005U (en) * | 2012-11-13 | 2013-07-10 | 范青青 | Switching power supply device of air purifier |
| CN103825465A (en) * | 2012-11-16 | 2014-05-28 | 力钜电子股份有限公司 | Isolated power converter, inverse shunt regulator and operation method thereof |
| CN104638896A (en) * | 2015-02-13 | 2015-05-20 | 矽恩微电子(厦门)有限公司 | Current clamping circuit based on BCD process |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| TWI387191B (en) * | 2009-06-02 | 2013-02-21 | Richtek Technology Corp | Voltage mode switching regulator and control circuit and method therefor |
-
2015
- 2015-09-18 CN CN201510595843.5A patent/CN106549581B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1937383A (en) * | 2005-09-22 | 2007-03-28 | 松下电器产业株式会社 | Switch power supply, semiconductor appatatus and controlling method |
| CN101997534A (en) * | 2009-08-13 | 2011-03-30 | 立锜科技股份有限公司 | Feedback circuit and control method for isolated power converter |
| CN203057005U (en) * | 2012-11-13 | 2013-07-10 | 范青青 | Switching power supply device of air purifier |
| CN103825465A (en) * | 2012-11-16 | 2014-05-28 | 力钜电子股份有限公司 | Isolated power converter, inverse shunt regulator and operation method thereof |
| CN104638896A (en) * | 2015-02-13 | 2015-05-20 | 矽恩微电子(厦门)有限公司 | Current clamping circuit based on BCD process |
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