CN106452021B - Inverse-excitation type switch power-supply circuit - Google Patents
Inverse-excitation type switch power-supply circuit Download PDFInfo
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- CN106452021B CN106452021B CN201611163836.9A CN201611163836A CN106452021B CN 106452021 B CN106452021 B CN 106452021B CN 201611163836 A CN201611163836 A CN 201611163836A CN 106452021 B CN106452021 B CN 106452021B
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- ncp1602
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Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/10—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers
-
- 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
- H02M1/00—Details of apparatus for conversion
- H02M1/32—Means for protecting converters other than automatic disconnection
-
- 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
- H02M1/00—Details of apparatus for conversion
- H02M1/36—Means for starting or stopping converters
-
- 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
- H02M1/00—Details of apparatus for conversion
- H02M1/0003—Details of control, feedback or regulation circuits
- H02M1/0006—Arrangements for supplying an adequate voltage to the control circuit of converters
Abstract
The present invention discloses a kind of inverse-excitation type switch power-supply circuit, wherein inverse-excitation type switch power-supply circuit includes NCP1602 chip, and voltage controls foot and the output end of feed circuit connects, and the input terminal of feed circuit is connect with secondary output circuit；Its grounding leg ground connection；It is sampled and the first end connection of monitoring foot and first resistor, the output end interconnection of the second end of first resistor, the first end of sampling resistor and switching tube, the second end ground connection of sampling resistor；It drives the first end of foot and second resistance to connect, the second end of second resistance and the controlled end of switching tube connect, the first end of the primary side winding of the input terminal and transformer of switching tube connects, the second end of transformer primary winding is connect with power input, and the vice-side winding of transformer is connect with secondary output circuit；Its supply pin is connect with the first auxiliary power circuit；It feeds back foot and connect with the second auxiliary power circuit.Technical solution of the present invention has the characteristics that at low cost.
Description
Technical field
The present invention relates to technical field of electronic equipment, in particular to a kind of inverse-excitation type switch power-supply circuit.
Background technique
Inverse-excitation type switch power-supply circuit is a kind of common Switching Power Supply topological circuit, and not only circuit structure is simple, may be used also
To realize multiple power supplies output and realize being isolated between alternating current and direct current, it is widely used in electronic equipment.
Off-line type reverse exciting switching voltage regulator circuit is realized based on dedicated chip design, according to the difference of control mode, dedicated core
Piece, which can be divided into, determines frequency chip and frequency conversion chip two major classes.Wherein, the inverse-excitation type switch power-supply circuit designed using frequency chip is determined,
Transformer winding may operate in continuous current mode and discontinuous current mode；The flyback switching designed using frequency conversion chip
Power circuit, transformer winding may operate in critical current mode.Further, frequency conversion chip can be divided into common frequency conversion core
Piece and modified frequency conversion chip.
For the inverse-excitation type switch power-supply circuit using the design of common frequency conversion chip, at light load, switching tube in circuit
Switching frequency increases, and switching loss increases；For the inverse-excitation type switch power-supply circuit using the design of modified frequency conversion chip, light
When load, the switching frequency of switching tube is reduced in circuit, and switching loss reduces.As a result, in circuit design process, it is generally preferable to adopt
With modified frequency conversion chip.However, the valence for the dedicated frequency conversion chip of modified off-line type flyback sourse sold on the market at present
Lattice are generally higher and kind is seldom.
NCP1602 and is exclusively used in the other of modified off-line type flyback sourse as one of modified frequency conversion chip
Modified frequency conversion chip is compared, and has the characteristics that pin is few, low-cost.Regrettably, in the prior art, NCP1602 chip
Switching Power Supply for BOOST PFC (Boost Power Factor Correction, boost type power PFC)
Design has not been used in inverse-excitation type switch power-supply design.
Summary of the invention
The main object of the present invention is to provide a kind of inverse-excitation type switch power-supply circuit, it is intended to reduce inverse-excitation type switch power-supply electricity
The cost on road.
To achieve the above object, inverse-excitation type switch power-supply circuit proposed by the present invention includes NCP1602 chip, feedback electricity
Road, first resistor, second resistance, sampling resistor, switching tube, transformer, the first auxiliary power circuit, the second accessory power supply electricity
Road, secondary output circuit and power input；The output end of voltage the control foot and the feed circuit of the NCP1602 chip
Connection, the input terminal of the feed circuit are connect with the secondary output circuit；The grounding leg of the NCP1602 chip is grounded；
The sampling of the NCP1602 chip and monitoring foot are connect with the first end of the first resistor, the second end of the first resistor,
The interconnection of the output end of the first end of the sampling resistor and the switching tube, the second end ground connection of the sampling resistor；It is described
The driving foot of NCP1602 chip is connect with the first end of the second resistance, the second end of the second resistance and the switch
The controlled end of pipe connects；The input terminal of the switching tube is connect with the first end of the primary side winding of the transformer, the transformation
The second end of device primary side winding is connect with the power input, the vice-side winding of the transformer and the secondary output circuit
Connection；The supply pin of the NCP1602 chip is connect with first auxiliary power circuit；The feedback of the NCP1602 chip
Foot is connect with second auxiliary power circuit.
Preferably, the inverse-excitation type switch power-supply circuit, which is characterized in that first auxiliary power circuit includes outer
Connect power supply and first capacitor, the output end of the external power supply, the first end of the first capacitor and the NCP1602 chip
Supply pin interconnection.
Preferably, the inverse-excitation type switch power-supply circuit further includes 3rd resistor, the first end of the 3rd resistor and institute
The first end connection of first resistor is stated, the second end of the 3rd resistor is connect with the input terminal of the switching tube.
Preferably, second auxiliary power circuit include the 4th resistance and the 5th resistance, the first of the 4th resistance
The feedback foot interconnection at end, the first end of the 5th resistance and the NCP1602 chip, the second termination of the 4th resistance
The second end on ground, the 5th resistance is connect with the power input.
Preferably, first auxiliary power circuit includes start-up circuit, auxiliary winding, first diode and the second electricity
Hold, the first end of the auxiliary winding is connect with the anode of the first diode, the second end ground connection of the auxiliary winding；Institute
State the supply pin and the start-up circuit of the cathode of first diode, the first end of second capacitor, the NCP1602 chip
Output end interconnection, the second end ground connection of second capacitor, the input terminal of the start-up circuit and the power input connect
It connects.
Preferably, second auxiliary power circuit include the 6th resistance and the 7th resistance, the first of the 6th resistance
The feedback foot interconnection at end, the first end of the 7th resistance and the NCP1602 chip, the second end of the 6th resistance and institute
State the cathode connection of the first end and the first diode of the second capacitor, the second end ground connection of the 7th resistance.
Preferably, the inverse-excitation type switch power-supply circuit further includes the 8th resistance, the 9th resistance, third capacitor and the two or two
The first end of pole pipe, the 9th resistance is connect with the first end of the first resistor, the second end of the 9th resistance, described
The interconnection of the first end of the anode of second diode and the third capacitor, the plus earth of second diode, the third
The second end of capacitor is connect with the first end of the 8th resistance, second end and the first diode of the 8th resistance
The connection of the first end of anode and the auxiliary winding.
Preferably, the inverse-excitation type switch power-supply circuit further includes the 4th capacitor, the first end of the 4th capacitor and institute
The input terminal connection of switching tube is stated, the second end of the 4th capacitor is connect with the output end of the switching tube.
Preferably, the inverse-excitation type switch power-supply circuit further includes the tenth resistance, the first end of the tenth resistance with
The sampling and monitoring foot connection, the second end of the tenth resistance and the first end of the first resistor of the NCP1602 chip
Connection.
Preferably, the inverse-excitation type switch power-supply circuit further includes eleventh resistor, the 5th capacitor and the 6th capacitor, described
The first end of 5th capacitor, the first end of the 6th capacitor, the voltage control foot of the NCP1602 chip and the feedback are electric
The output end on road interconnects, and the second end of the 5th capacitor is connect with the first end of the eleventh resistor, the 11st electricity
The second end of resistance and the second end of the 6th capacitor are grounded.
Since the inverse-excitation type switch power-supply circuit that technical solution of the present invention proposes is realized based on the design of NCP1602 chip
, and inverse-excitation type switch power-supply circuit disclosed in the prior art is based on the dedicated flyback higher than NCP1602 chip price mostly
The design of formula switching power source chip is realized.Accordingly, with respect to the prior art, technical solution of the present invention reduces flyback switching electricity
The cost of source circuit.
Detailed description of the invention
In order to more clearly explain the embodiment of the invention or the technical proposal in the existing technology, to embodiment or will show below
There is attached drawing needed in technical description to be briefly described, it should be apparent that, the accompanying drawings in the following description is only this
Some embodiments of invention for those of ordinary skill in the art without creative efforts, can be with
The structure shown according to these attached drawings obtains other attached drawings.
Fig. 1 is the electrical block diagram of one embodiment of inverse-excitation type switch power-supply circuit of the present invention；
Fig. 2 is the electrical block diagram of another embodiment of inverse-excitation type switch power-supply circuit of the present invention；
Fig. 3 is the electrical block diagram of the another embodiment of inverse-excitation type switch power-supply circuit of the present invention.
Drawing reference numeral explanation:
| Label | Title | Label | Title | Label | Title |
| 10 | First auxiliary power circuit | R1 | First resistor | C1 | First capacitor |
| 20 | Secondary output circuit | R2 | Second resistance | C2 | Second capacitor |
| 30 | Feed circuit | R3 | 3rd resistor | C3 | Third capacitor |
| 40 | Second auxiliary power circuit | R4 | 4th resistance | C3 | 4th capacitor |
| U1 | NCP1602 chip | R5 | 5th resistance | C4 | 5th capacitor |
| U2 | Optocoupler | R6 | 6th resistance | C5 | 6th capacitor |
| D1 | First diode | R7 | 7th resistance | C6 | 7th capacitor |
| D2 | Second diode | R8 | 8th resistance | TR | Transformer |
| Q | Switching tube | R9 | 9th resistance | NS | Primary side winding |
| R11 | Eleventh resistor | R10 | Tenth resistance | NP | Vice-side winding |
| VC | External power supply | RS | Sampling resistor | NAUX | Auxiliary winding |
The embodiments will be further described with reference to the accompanying drawings for the realization, the function and the advantages of the object of the present invention.
Specific embodiment
Following will be combined with the drawings in the embodiments of the present invention, and technical solution in the embodiment of the present invention carries out clear, complete
Site preparation description, it is clear that described embodiment is only a part of the embodiments of the present invention, instead of all the embodiments.Base
Embodiment in the present invention, it is obtained by those of ordinary skill in the art without making creative efforts it is all its
His embodiment, shall fall within the protection scope of the present invention.
It is to be appreciated that if the directional instruction (such as up, down, left, right, before and after ...) of institute in the embodiment of the present invention,
It is only used for explaining in relative positional relationship, the motion conditions etc. under a certain particular pose (as shown in the picture) between each component, such as
The fruit particular pose changes, then directionality instruction also correspondingly changes correspondingly.
In addition, the description for being related to " first ", " second " etc. in the present invention is used for description purposes only, and should not be understood as referring to
Show or imply its relative importance or implicitly indicates the quantity of indicated technical characteristic." first ", " are defined as a result,
Two " feature can explicitly or implicitly include at least one of the features.In addition, the technical solution between each embodiment can
It to be combined with each other, but must be based on can be realized by those of ordinary skill in the art, when the combination of technical solution occurs
Conflicting or cannot achieve when, will be understood that the combination of this technical solution is not present, also not the present invention claims protection model
Within enclosing.
The present invention proposes a kind of inverse-excitation type switch power-supply circuit, which is based on NCP1602 chip
Design is realized.Since NCP1602 chip has the characteristics that at low cost, pin is few, flyback switching electricity proposed by the present invention
Source circuit correspondence has the characteristics that at low cost, material is few, these features will be embodied in each of the embodiments described below.
It should be noted that as shown in Figure 1, NCP1602 chip U1 has voltage control foot VCTRL, grounding leg GND, adopts
Sample and monitoring foot CS/ZCD, driving foot DRV, supply pin VCC and feedback foot FB.Wherein, driving foot DRV is used to export PWM wave, when
The voltage of voltage control foot VCTRL is fallen in when changing, the high level lasting time of the PWM wave of driving foot DRV output is corresponding
Change；When the input voltage or input current that sample and monitor foot CS/ZCD change, the PWM of driving foot DRV output
Wave is also corresponding to be changed.In general, feedback foot FB connects biased electrical if supply pin VCC obtains power supply, grounding leg GND ground connection
Source, NCP1602 chip U1 can start to work.However, in the NCP1602 chip U1 course of work, if falling in its feedback
The voltage of foot FB is more than 2.5V, then NCP1602 chip U1 will stop working.
In addition, switching tube Q refers both to N-MOS pipe in following the description, the drain electrode of the N-MOS pipe is the input terminal of switching tube Q,
The source electrode of the N-MOS pipe is the output end of switching tube Q, and the grid of the N-MOS pipe is the controlled end of switching tube Q.
Referring to Fig. 1, in one embodiment, inverse-excitation type switch power-supply circuit proposed by the present invention includes NCP1602 chip
U1, feed circuit 30, first resistor R1, second resistance R2, sampling resistor RS, switching tube Q, transformer TR, the first accessory power supply
Circuit 10, the second auxiliary power circuit 40, secondary output circuit 20 and power input VI；The voltage control of NCP1602 chip U1
Foot VCTRL processed is connect with the output end of feed circuit 30, and the input terminal of feed circuit 30 is connect with secondary output circuit 20；
The grounding leg GND of NCP1602 chip U1 is grounded；The sampling of NCP1602 chip U1 and monitoring foot CS/ZCD's and first resistor R1
First end connection, the output end interconnection of the second end of first resistor R1, the first end of sampling resistor RS and switching tube Q, sampling electricity
Hinder the second end ground connection of RS；The driving foot DRV of NCP1602 chip U1 is connect with the first end of second resistance RS, second resistance RS
Second end connect with the controlled end of switching tube Q；The input terminal of switching tube Q is connect with the first end of transformer primary winding NP,
The second end of transformer primary winding NP is connect with power input VI, and transformer secondary winding NS and secondary output circuit 20 connect
It connects；The supply pin VCC of NCP1602 chip U1 is connect with the first auxiliary power circuit 10；The feedback foot FB of NCP1602 chip U1 with
The connection of second auxiliary power circuit 40.
When power input VI obtain input power, NCP1602 chip U1 supply pin VCC obtain power supply,
When the feedback foot FB of NCP1602 chip U1 obtains bias supply, inverse-excitation type switch power-supply circuit is started to work.In flyback switching
In the power circuit course of work:
If the driving foot DRV of NCP1602 chip U1 exports high level, switching tube Q conducting, transformer primary winding NP has
Primary current flows through.Here, the voltage for falling in the voltage control foot VCTRL of NCP1602 chip U1 determines the peak value of primary current.
First end of the primary current in sampling resistor RS generates sampled voltage, which is input to by first resistor RS
The sampling of NCP1602 chip U1 and monitoring foot CS/ZCD, realize sampling monitoring and the overcurrent protection of inverse-excitation type switch power-supply circuit
Function.
If the driving foot DRV of NCP1602 chip U1 exports low level, switching tube cut-off flows through the electricity of transformer primary side
Stream is transmitted to transformer secondary, and the power supply of powering load is exported by secondary output circuit 20.When secondary output circuit 20
There are when deviation between the practical power of output and default power supply, secondary output circuit 20 exports corresponding error signal, and leads to
The voltage control foot VCTRL that feed circuit 30 feeds back to NCP1602 chip U1 is crossed, to change the electricity for falling in NCP1602 chip U1
The voltage of voltage-controlled foot VCTRL processed, and then change the peak value of primary current, eliminate the practical power of secondary output circuit output 20 with
Deviation between default power supply.
Inverse-excitation type switch power-supply circuit is achieved that power supply exports pressure stabilizing regulatory function as a result,.
Based on an above-mentioned embodiment, referring to Fig. 2, in another embodiment, technical solution of the present invention is also to inverse-excitation type
Switching power circuit has done following improvement, to advanced optimize the performance of inverse-excitation type switch power-supply circuit:
(1) 3rd resistor R3 is added, to avoid the feelings for burning out device due to there is the overtension because being added in switching tube Q drain electrode
Condition realizes switching tube Q over-voltage protecting function.Specifically, the first end of the first end of 3rd resistor R3 and above-mentioned first resistor R1
Connection, the second end of 3rd resistor R2 are connect with the input terminal of switching tube Q.In the inverse-excitation type switch power-supply circuit course of work,
The voltage for being added in switching tube Q drain electrode feeds back to sampling and the monitoring foot CS/ZCD of NCP1602 chip U1 by 3rd resistor R3, if
It is added in the overtension of switching tube Q drain electrode, then NCP1602 chip U1 opens overvoltage protection.
(2) input power is provided by the 4th resistance R4 and the 5th resistance R5 to the feedback foot FB of NCP1602 chip U1
Bias supply normally can start and work by power circuit, while monitoring input voltage again, avoid because input supply voltage is excessively high
And power supply is burnt out, realize the input over-voltage protecting function of inverse-excitation type switch power-supply circuit.Specifically, the first of the 4th resistance R4
The feedback foot FB interconnection at end, the first end of the 5th resistance R5 and NCP1602 chip U1, the second end ground connection of the 4th resistance R4, the
The second end of five resistance R5 is connect with power input VI.In the inverse-excitation type switch power-supply circuit course of work, work as input power
When voltage is bigger, the voltage for falling in the 4th resistance R4 first end is also bigger, and if falling in the first end of the 4th resistance R4
Voltage is greater than 2.5V, then NCP1602 chip U1 opens overvoltage protection.
(3) the 4th capacitor C4 is added, point caused by transformer primary leakage inductance storage energy when absorbing switching tube Q shutdown
Peak voltage.Specifically, the first end of the 4th capacitor C4 is connect with the input terminal of switching tube Q, the second end of the 4th capacitor C4 with open
Close the output end connection of pipe Q.In the inverse-excitation type switch power-supply circuit course of work, when switching tube Q shutdown, leakage inductance energy is to the
Four capacitor C4 charge and all in the presence of in the 4th capacitor C4；Transformer secondary output output electric current drop to zero and before switching tube Q opens,
4th capacitor C4 carries out feedback electric discharge to input power by primary winding.In this way, the 4th capacitor C4 both can be absorbed
Switching tube Q generated peak voltage when turning off, and leakage inductance energy can be fed back to input power to improve efficiency.
(4) the tenth resistance R10 is added, it is dry to the signal generation for being input to NCP1602 chip U1 to resist other signals
It disturbs.Specifically, the first end of the tenth resistance R10 is connect with the sampling of NCP1602 chip U1 and monitoring foot CS/ZCD, the tenth resistance
The second end of R10 is connect with the first end of first resistor R10.In the inverse-excitation type switch power-supply circuit course of work, the tenth resistance
Capacitor inside R10 and NCP1602 chip U1 constitutes filter circuit.It is input to NCP1602 chip U1's in this manner it is possible to filter
The interference signal of sampling and monitoring foot CS/ZCD.
(5) the pid correction circuit being made of eleventh resistor R11, the 5th capacitor C5 and the 6th capacitor C6 is added, so that electric
Road more stably works.Specifically, the first end of the 5th capacitor C5, the first end of the 6th capacitor C6, NCP1602 chip U1 electricity
The interconnection of the output end of voltage-controlled foot VCTRL processed and feed circuit 30, the second end of the 5th capacitor C5 and the first of eleventh resistor R11
The second end of end connection, the second end of eleventh resistor R11 and the 6th capacitor C6 are grounded.
It is noted that the first auxiliary power circuit 10 includes external power supply VC and first capacitor C1 in the present embodiment,
The supply pin VCC of the output end of external power supply VC, the first end of first capacitor C1 and NCP1602 chip U1 is interconnected.In addition, feedback
Circuit 30 includes optocoupler U2, and the anode of optocoupler U2 is connect with secondary output circuit 20, the collector and NCP1602 chip of optocoupler U2
The voltage of U1 controls foot VCTRL connection, and the anode and emitter of optocoupler U2 is grounded.When the secondary that the anode of optocoupler U2 receives
When the error signal that output circuit 20 exports changes, the conducting degree of optocoupler U2 is corresponding to be changed, and then is changed and fallen in NCP1602 core
The voltage of the voltage control foot VCTRL of piece U1.It is understood that feed circuit 30 can also be realized by triode, triode
Base stage connect with secondary output circuit 20, the collector of triode and the voltage control foot VCTRL company of NCP1602 chip U1
It connects, the emitter ground connection of triode.When transistor base, which receives the error signal that secondary output circuit 20 exports, to be changed, three
The conducting degree of pole pipe is corresponding to be changed, and then changes the voltage control foot VCTRL voltage for falling in NCP1602 chip U1.However, phase
For triode, optocoupler U2 also has the function of isolating transformer TR primary and secondary, improves the safety of circuit.
Hereinafter, illustrating the working principle of inverse-excitation type switch power-supply circuit in the present embodiment in conjunction with Fig. 2:
In the inverse-excitation type switch power-supply circuit course of work:
When input supply voltage is greater than input threshold voltage, the voltage for falling in the first end of the 4th resistance R4 is greater than
2.5V, NCP1602 chip U1 do not work, and realize input over-voltage protecting function.When input supply voltage is less than or equal to input
When threshold voltage, the voltage for falling in the first end of the 4th resistance R4 is less than or equal to 2.5V, NCP1602 chip U1 work:
If the driving foot DRV of NCP1602 chip U1 exports high level, switching tube Q conducting.Sampling resistor RS acquisition is flowed through
The electric current of transformer primary winding NS, and the sampling of NCP1602 chip U1 is fed back to by first resistor R1 and monitors foot CS/
ZCD realizes the function of Current Feedback Control and output overcurrent protection.
If the driving foot DRV of NCP1602 chip U1 exports low level, switching tube Q cut-off.4th capacitor C4 absorbs switch
Peak voltage caused by transformer primary leakage inductance storage energy, the voltage for being added in switching tube Q drain electrode pass through third when pipe Q is turned off
Resistance R3 feeds back to sampling and the monitoring foot CS/ZCD of NCP1602 chip U1, realizes output over-voltage protection function.
Based on an above-mentioned embodiment, referring to Fig. 3, in another embodiment, technical solution of the present invention is also to inverse-excitation type
Switching power circuit has done following improvement, to advanced optimize the performance of inverse-excitation type switch power-supply circuit:
(1) the first accessory power supply is formed using start-up circuit, auxiliary winding NAUX, first diode D1 and the second capacitor C2
Circuit 10 is NCP1602 chip U1 power supply, saves external power supply VC, further decreases the cost of inverse-excitation type switch power-supply circuit.
Specifically, the first end of auxiliary winding NAUX is connect with the anode of first diode D1, the second end ground connection of auxiliary winding NAUX；
The cathode of first diode D1, the first end of the second capacitor C2, the supply pin VCC of NCP1602 chip U1 and start-up circuit it is defeated
Outlet interconnection, the second end ground connection of the second capacitor C2, the input terminal of start-up circuit are connect with power input.Wherein, exist
Before NCP1602 chip U1 is opened, NCP1602 chip U1 obtains power supply from power input by start-up circuit；?
After NCP1602 chip U1 is opened, auxiliary winding NAUX incudes electric by magnetic core of transformer, and the power supply incuded is through the one or two pole
It is exported after pipe D1 rectification, the second capacitor C2 filtering, using the power supply as NCP1602 chip U1.
(2) out-put supply of the first auxiliary power circuit 10 is made to pass through the 6th circuit R6 and the 7th resistance R7 to NCP1602
The feedback foot of chip U1, which provides bias supply, normally can start and work by power circuit, while monitor output voltage again, realize
The output over-voltage protection function of inverse-excitation type switch power-supply circuit.Specifically, the first end of the 6th resistance R6, the 7th resistance R7
The feedback foot FB of one end and NCP1602 chip U1 interconnection, the second end of the 6th resistance R6 and the first end of the second capacitor C2 and the
The cathode of one diode D1 connects, the second end ground connection of the 7th resistance R7.Before NCP1602 chip U1 unlatching, auxiliary winding
NAUX not it is electric, start-up circuit 40 open, provide bias supply by input power for NCP1602 chip U1；In NCP1602 chip
After U1 is opened, auxiliary winding NAUX obtains electric, the shutdown of start-up circuit 40, by the out-put supply of the first auxiliary power circuit 10 through the 6th
Bias supply is provided after resistance R6 and the 7th resistance R7 partial pressure for NCP1602 chip U1.Wherein, the first auxiliary power circuit 10 wraps
Include above-mentioned start-up circuit, auxiliary winding NAUX, first diode D1 and the second capacitor C2.When power circuit output supply voltage
When bigger, the voltage that auxiliary winding NAUX is obtained is bigger, and the voltage for falling in the 6th resistance R6 first end is also bigger, and if
The voltage for falling in the 6th resistance R6 first end is greater than 2.5V, then NCP1602 chip U1 opens output over-voltage protection.
(3) the 8th resistance R8, the 9th resistance R9, third capacitor C3 and the second diode D2 are added, to realize that inverse-excitation type is opened
The zero crossing detection function of powered-down source circuit.Specifically, the first end of the 9th resistance R9 is connect with the first end of first resistor R1, the
The first end of the second end of nine resistance R9, the anode of the second diode D2 and third capacitor C3 interconnects, the sun of the second diode D2
Pole ground connection, the second end of third capacitor C3 are connect with the first end of the 8th resistance R8, the second end and the one or two of the 8th resistance R8
The first end connection of the anode and auxiliary winding NAUX of pole pipe D1.In the inverse-excitation type switch power-supply circuit course of work, auxiliary around
The voltage of group NAUX first end is fed back to by the 8th resistance R8, third capacitor C3, the second diode D2 and the 9th resistance R9
The sampling of NCP1602 chip U1 and monitoring foot CS/ZCD.
(4) the 4th capacitor C4 is added, point caused by transformer primary leakage inductance storage energy when absorbing switching tube shutdown
Peak voltage.Specifically, the first end of the 4th capacitor C4 is connect with the input terminal of switching tube Q, the second end of the 4th capacitor C4 with open
Close the output end connection of pipe Q.In the inverse-excitation type switch power-supply circuit course of work, when switching tube Q shutdown, leakage inductance energy is to the
Four capacitor C4 charge and all in the presence of in the 4th capacitor C4；Transformer secondary output output electric current drop to zero and before switching tube Q opens,
4th capacitor C4 carries out feedback electric discharge to input power by primary winding.In this way, the 4th capacitor C4 both can be absorbed
Switching tube Q generated peak voltage when turning off, and leakage inductance energy can be fed back to input power to improve efficiency.
(5) the tenth resistance R10 is added, to resist sampling and monitoring foot of the other signals to NCP1602 chip U1 is input to
The signal of CS/ZCD generates interference.Specifically, the sampling of the first end of the tenth resistance R10 and NCP1602 chip U1 and monitoring foot
CS/ZCD connection, the second end of the tenth resistance R10 are connect with the first end of first resistor R1.In inverse-excitation type switch power-supply circuit work
During work, the capacitor inside the tenth resistance R10 and NCP1602 chip U1 constitutes filter circuit.In this manner it is possible to filter input
To the sampling of NCP1602 chip U1 and the interference signal of monitoring foot CS/ZCD.
(6) the pid correction circuit being made of eleventh resistor R11, the 5th capacitor C5 and the 6th capacitor C6 is added, so that electric
Road more stably works.Specifically, the first end of the 5th capacitor C5, the first end of the 6th capacitor C6, NCP1602 chip U1 electricity
The interconnection of the output end of voltage-controlled foot VCTRL processed and feed circuit 30, the second end of the 5th capacitor C5 and the first of eleventh resistor R11
The second end of end connection, the second end of eleventh resistor R11 and the 6th capacitor C6 are grounded.
It is noted that feed circuit 30 includes optocoupler U2, the anode of optocoupler U2 and secondary output electricity in the present embodiment
Road 20 connects, and the collector of optocoupler U2 is connect with the voltage of NCP1602 chip U1 control foot VCTRL, the anode and hair of optocoupler U2
Emitter-base bandgap grading is grounded.When the anode of optocoupler U2, which receives the error signal that secondary output circuit 20 exports, to be changed, optocoupler U2's is led
Logical degree is corresponding to be changed, and then changes the voltage for falling in the voltage control foot VCTRL of NCP1602 chip U1.It is understood that
Feed circuit 30 can also have triode realization, and the base stage of triode is connect with secondary output circuit 20, the collector of triode
It is connect with the voltage of NCP1602 chip U1 control foot VCTRL, the emitter ground connection of triode.When transistor base receives time
When the error signal that grade output circuit 20 exports changes, the conducting degree of triode is corresponding to be changed, and then is changed and fallen in NCP1602
The voltage of chip U1 controls foot VCTRL voltage.However, relative to triode, optocoupler U2 also have isolating transformer TR primary and
Secondary function, improves the safety of circuit.
Hereinafter, illustrating the working principle of inverse-excitation type switch power-supply circuit in the present embodiment in conjunction with Fig. 3:
NCP1602 chip U1 unlatching before, auxiliary winding NAUX not it is electric, by input power pass through start-up circuit 40 give
NCP1602 chip U1 provides power supply and bias supply；NCP1602 chip U1 unlatching after, auxiliary winding NAUX obtain it is electric, by
First auxiliary power circuit 10 of auxiliary winding NAUX, first diode D1 and the second capacitor C2 composition gives NCP1602 chip U1
Power supply is provided, the out-put supply of the first auxiliary power circuit 10 is after the 6th resistance R6 and the 7th resistance R7 partial pressure
NCP1602 chip U1 provides bias supply.In the inverse-excitation type switch power-supply circuit course of work:
If the driving foot DRV of NCP1602 chip U1 exports high level, switching tube Q conducting, sampling resistor RS acquisition is flowed through
The electric current of transformer primary winding NS, and the sampling of NCP1602 chip U1 is fed back to by first resistor R1 and monitors foot CS/
ZCD realizes the function of Current Feedback Control and output overcurrent protection.
If the driving foot DRV of NCP1602 chip U1 exports low level, switching tube Q cut-off, the 4th capacitor C4 absorbs switch
Peak voltage caused by transformer primary leakage inductance storage energy when pipe Q is turned off.
When output supply voltage is greater than output threshold voltage, the voltage for falling in the 6th resistance R6 first end is greater than 2.5V,
NCP1602 chip U1 stops working, and realizes output over-voltage protection function.When output voltage is less than or equal to output threshold voltage
When, the voltage for falling in the first end of the 6th resistance R6 is less than or equal to 2.5V, and NCP1602 chip U1 keeps work.
The present invention also proposes a kind of electronic equipment, which includes inverse-excitation type switch power-supply circuit as described above,
The specific structure of the inverse-excitation type switch power-supply circuit is referring to above-described embodiment, since this electronic equipment uses above-mentioned all implementations
Whole technical solutions of example, therefore at least all beneficial effects brought by the technical solution with above-described embodiment, herein not
It repeats one by one again.Wherein, which can be television set, refrigerator etc..
The above description is only a preferred embodiment of the present invention, is not intended to limit the scope of the invention, all at this
Under the inventive concept of invention, using equivalent structure transformation made by description of the invention and accompanying drawing content, or directly/use indirectly
It is included in other related technical areas in scope of patent protection of the invention.
Claims (10)
1. a kind of inverse-excitation type switch power-supply circuit, which is characterized in that including NCP1602 chip, feed circuit, first resistor,
Two resistance, sampling resistor, switching tube, transformer, the first auxiliary power circuit, the second auxiliary power circuit, secondary output circuit
And power input；
The voltage control foot of the NCP1602 chip is connect with the output end of the feed circuit, the input of the feed circuit
End is connect with the secondary output circuit, and the voltage control foot of the NCP1602 chip is for receiving the secondary output circuit
The error signal fed back by the feed circuit；
The grounding leg of the NCP1602 chip is grounded；
The sampling of the NCP1602 chip and monitoring foot are connect with the first end of the first resistor, and the of the first resistor
The output end at two ends, the first end of the sampling resistor and the switching tube interconnects, the second end ground connection of the sampling resistor；
The driving foot of the NCP1602 chip is connect with the first end of the second resistance, the second end of the second resistance with
The controlled end of the switching tube connects；The input terminal of the switching tube is connect with the first end of the primary side winding of the transformer,
The second end of the transformer primary winding is connect with the power input, the vice-side winding of the transformer and the secondary
Output circuit connection；
The supply pin of the NCP1602 chip is connect with first auxiliary power circuit；
The feedback foot of the NCP1602 chip is connect with second auxiliary power circuit.
2. inverse-excitation type switch power-supply circuit as described in claim 1, which is characterized in that first auxiliary power circuit includes
External power supply and first capacitor, the output end of the external power supply, the first end of the first capacitor and the NCP1602 chip
Supply pin interconnection.
3. inverse-excitation type switch power-supply circuit as described in claim 1, which is characterized in that the inverse-excitation type switch power-supply circuit is also
Including 3rd resistor, the first end of the 3rd resistor is connect with the first end of the first resistor, and the of the 3rd resistor
Two ends are connect with the input terminal of the switching tube.
4. inverse-excitation type switch power-supply circuit as described in claim 1, which is characterized in that second auxiliary power circuit includes
4th resistance and the 5th resistance, the first end of the 4th resistance, the first end of the 5th resistance and the NCP1602 chip
The interconnection of feedback foot, the second end ground connection of the 4th resistance, the second end of the 5th resistance and the power input connect
It connects.
5. inverse-excitation type switch power-supply circuit as described in claim 1, which is characterized in that first auxiliary power circuit includes
Start-up circuit, auxiliary winding, first diode and the second capacitor, the first end of the auxiliary winding and the first diode
Anode connection, the second end ground connection of the auxiliary winding；The cathode of the first diode, second capacitor first end,
The output end interconnection of the supply pin and the start-up circuit of the NCP1602 chip, the second end ground connection of second capacitor, institute
The input terminal for stating start-up circuit is connect with the power input.
6. inverse-excitation type switch power-supply circuit as claimed in claim 5, which is characterized in that second auxiliary power circuit includes
6th resistance and the 7th resistance, the first end of the 6th resistance, the first end of the 7th resistance and the NCP1602 chip
The interconnection of feedback foot, the cathode of the first end of the second end of the 6th resistance and second capacitor, the first diode
And the output end connection of the start-up circuit, the second end ground connection of the 7th resistance.
7. inverse-excitation type switch power-supply circuit as claimed in claim 6, which is characterized in that the inverse-excitation type switch power-supply circuit is also
Including the 8th resistance, the 9th resistance, third capacitor and the second diode, the first end and the first resistor of the 9th resistance
First end connection, the first end of the second end of the 9th resistance, the cathode of second diode and the third capacitor
Interconnection, the plus earth of second diode, the second end of the third capacitor are connect with the first end of the 8th resistance,
The second end of 8th resistance is connect with the first end of the anode of the first diode and the auxiliary winding.
8. the inverse-excitation type switch power-supply circuit as described in claim 1-7 any one, which is characterized in that the flyback switching
Power circuit further includes the 4th capacitor, and the first end of the 4th capacitor is connect with the input terminal of the switching tube, and the described 4th
The second end of capacitor is connect with the output end of the switching tube.
9. the inverse-excitation type switch power-supply circuit as described in claim 1-7 any one, which is characterized in that the inverse-excitation type is opened
Powered-down source circuit further includes the tenth resistance, the first end of the tenth resistance and the sampling of the NCP1602 chip and monitoring foot
Connection, the second end of the tenth resistance are connect with the first end of the first resistor.
10. the inverse-excitation type switch power-supply circuit as described in claim 1-7 any one, which is characterized in that the inverse-excitation type is opened
Powered-down source circuit further includes eleventh resistor, the 5th capacitor and the 6th capacitor, the first end of the 5th capacitor, the 6th electricity
The output end interconnection of the first end of appearance, the voltage control foot of the NCP1602 chip and the feed circuit, the 5th capacitor
Second end connect with the first end of the eleventh resistor, the of the second end of the eleventh resistor and the 6th capacitor
Two ends are grounded.
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| CN201611163836.9A CN106452021B (en) | 2016-12-14 | 2016-12-14 | Inverse-excitation type switch power-supply circuit |
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|---|---|---|---|
| CN201611163836.9A CN106452021B (en) | 2016-12-14 | 2016-12-14 | Inverse-excitation type switch power-supply circuit |
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| CN106452021B true CN106452021B (en) | 2019-08-16 |
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| CN107769569A (en) * | 2017-10-13 | 2018-03-06 | 深圳市盛弘电气股份有限公司 | A kind of half bridge flyback resonance circuit |
| CN115603283B (en) * | 2022-11-21 | 2023-03-21 | 珠海智融科技股份有限公司 | Flyback protection circuit |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN205378285U (en) * | 2016-01-26 | 2016-07-06 | 安徽工程大学 | LED lamp lighting system based on PWM adjusts luminance |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN205378285U (en) * | 2016-01-26 | 2016-07-06 | 安徽工程大学 | LED lamp lighting system based on PWM adjusts luminance |
Non-Patent Citations (1)
| Title |
|---|
| NCP1602;www.alldatasheet.com;《www.alldatasheet.com》;20151031;第1-4页，图1 |
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