CN103944147A - Switching power protection circuit and control method thereof - Google Patents
Switching power protection circuit and control method thereof Download PDFInfo
- Publication number
- CN103944147A CN103944147A CN201410182577.9A CN201410182577A CN103944147A CN 103944147 A CN103944147 A CN 103944147A CN 201410182577 A CN201410182577 A CN 201410182577A CN 103944147 A CN103944147 A CN 103944147A
- Authority
- CN
- China
- Prior art keywords
- output
- circuit
- current
- comparator
- input
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Abstract
The invention discloses a switching power protection circuit and a control method thereof. The switching power protection circuit comprises an input filter circuit, a power conversion circuit, a high-frequency transformer, an output rectifying circuit, an output filter circuit, a driving control circuit, an output feedback control circuit and an over-current protection circuit, the output filter circuit comprises an output filter inductor, and the over-current protection circuit comprises a current conditioning circuit and an output current sampling circuit. The output current sampling circuit and the current conditioning circuit are added into the switching power protection circuit, the sampling circuit almost can be free of power loss, a certain condition is created for power efficiency improvement, switching power output efficiency is improved, line loss of the switching power protection circuit is reduced, and interference resistance is high.
Description
Technical field
The present invention relates to switching power circuit field, be specifically related to a kind of protective circuit of switch power source and control method thereof.
Background technology
Protective circuit of switch power source is the important component part in switch power supply system.Its effect is when Switching Power Supply is in system debug or use procedure, and the power component in can protection switch power supply and other circuit working of system are in safety zone.Switching Power Supply current foldback circuit is one of core cell of protective circuit of switch power source.In the time that the output institute bringing onto load of power supply exceedes nominal load, can cause damage to power supply, the power component that current foldback circuit can effective guarantee switch power supply system and system power supply circuit working are in safety zone.
The form of overcurrent protection has a variety of, mainly can be divided into two large classes: a class is cut-off type overcurrent protection, and a class is automatically to recover type overcurrent protection.In certain applications and design, adopt cut-off type overcurrent protection mode, the reliability of power supply has improved like this, but occurs to need manually to reset after overcurrent at every turn, and this uses for user can be not too convenient.So, generally adopt automatic recovery type more.At present; automatically the overcurrent protection of recovery type mainly adopts the sagging type current foldback circuit of rated current; this current foldback circuit is mainly in output current loop, to access sample resistance; and then by the over-current signal processing of this current sampling signal; the shortcoming of this current protecting circuit is mainly the existence of sample resistance; reduced the efficiency of power supply, especially, the in the situation that of High-current output, ohmically power consumption can obviously increase.Therefore, consider power consumption, should avoid the access of sample resistance as far as possible.
Summary of the invention
The technical problem to be solved in the present invention is to provide a kind of protective circuit of switch power source and control method thereof; change the structure of original current foldback circuit; this circuit has not only improved Switching Power Supply delivery efficiency, reduced the line loss of circuit, and antijamming capability is strong.
For solving the problems of the technologies described above, the present invention by the following technical solutions:
A kind of protective circuit of switch power source, comprise input filter circuit, circuit for power conversion, high frequency transformer, output rectification circuit, output filter circuit, Drive and Control Circuit, output feedback control circuit, current foldback circuit, described output filter circuit comprises output inductor, and described current foldback circuit comprises current regulating circuit and output current sample circuit; Described input filter circuit is connected with the output of described Drive and Control Circuit, the input of described high frequency transformer respectively via described circuit for power conversion; The input of described Drive and Control Circuit is connected with the output of the output of described input filter circuit, described output feedback control circuit; The output of described high frequency transformer is connected with power source loads via described output rectification circuit, output filter circuit; The output of described output filter circuit is connected with the input of output current sample circuit, the input of described output feedback control circuit is connected with the output of current regulating circuit, the output of output filter circuit, and the input of described current regulating circuit is connected with the output of described output current sample circuit.
Described output current sample circuit is made up of sample coil and resistance, described sample coil and output inductor and be wound on same magnetic core, the Same Name of Ends of sample coil is connected with the Same Name of Ends of output inductor, and the different name end of sample coil is connected with output inductor different name end by resistance.
Described current regulating circuit comprises the amplifying circuit being made up of amplifier, the comparison circuit being made up of comparator; The in-phase input end of described amplifier is connected with the different name end of sample coil, and the output of described comparator is connected with output feedback control circuit.
A kind of protective circuit of switch power source control method, is characterized in that, comprises the steps,
A: current sampling signal is realized to signal through operational amplifier U1 and amplify;
B: the current sampling signal after operational amplifier U1 amplifies is input to the forward end of comparator U2, compares the magnitude of voltage of itself and comparator U2 backward end, and in the time that power supply is normally worked, comparator U2 does not overturn; When load current reaches over-current protection point, comparator U2 overturns, and now, U2 is output as high level;
C: comparator U2 output signal is sent to the feedback comparator U3 in output feedback control circuit, in the time of U2 output high level, U3 reference voltage is dragged down, and output voltage sampled signal is greater than reference voltage, feedback comparator U3 output low level, the On current of triode Q1 increases; In the time that the On current of triode Q1 reaches 1mA, the elementary pulse width controller of power supply stops exporting half-bridge two-way and drives signal, and output voltage is dragged down.
The invention has the beneficial effects as follows: 1, in circuit, increased output current sample circuit and current regulating circuit, this sample circuit almost can be accomplished no power waste, this has created certain condition for power-efficient improves, not only improve Switching Power Supply delivery efficiency, reduced the line loss of circuit, and antijamming capability is strong.2, sample coil is on output inductor, and both are wound on same magnetic core, and sample circuit device is less, implements more convenient.3, in-55 DEG C～+ 125 DEG C temperature ranges, work, can reach in the time that power source loads exceedes 1.4 times of nominal load, effectively carry out overcurrent protection; Product integrated level is high, good reliability.
Brief description of the drawings
Fig. 1 is circuit block diagram of the present invention;
Fig. 2 is output current sample circuit of the present invention;
Fig. 3 is current regulating circuit of the present invention.
Embodiment
Below in conjunction with accompanying drawing, the invention will be further described.
As shown in Figure 1, a kind of protective circuit of switch power source and control method thereof are made up of input filter circuit 1, circuit for power conversion 2, high frequency transformer 3, output rectification circuit 4, output filter circuit 5, output feedback control circuit 8, Drive and Control Circuit 7, current foldback circuit.Current foldback circuit comprises current regulating circuit 9 and output current sample circuit 10; Input filter circuit 1 is connected with the output of Drive and Control Circuit 7, the input of high frequency transformer 3 respectively via circuit for power conversion 2; The input of Drive and Control Circuit 7 is connected with the output of input filter circuit 1, the output of output feedback control circuit 8; The output of high frequency transformer is connected with power source loads 6 via output rectification circuit 4, output filter circuit 5; The output of output filter circuit 5 is connected with the input of output current sample circuit 10, the output of the output input of feedback control circuit 8 and the output of current regulating circuit 9, output filter circuit 5 is connected, and the input of current regulating circuit 9 is connected with the output of output current sample circuit 10.
The direct voltage of input is through input filter circuit 1, the operating voltage of Drive and Control Circuit 7 is provided by accessory power supply, Drive and Control Circuit 7 produces the driving signal of power switch pipe in circuit for power conversion 2, isolate, be coupled through high frequency transformer 3, output obtains needed direct voltage through output rectification circuit 4 and output filter circuit 5.In order to realize the stable of output voltage, output feedback control circuit 8 adopts output voltage direct sample, after feeding back with comparison, amplification and the isolation of reference voltage, go to control the duty ratio of pulse width modulator in Drive and Control Circuit 7, thereby realize the closed-loop control of output voltage.The output current of power supply arrives output feedback control circuit 8 through output current sample circuit 10 and through current regulating circuit 9 output voltage signals, finally controls the voltage at power source loads 6 two ends.
As shown in Figure 2, output current sample circuit is made up of sample coil L2 and resistance R; Sample coil L2 and output inductor L1 and be wound on same magnetic core, the Same Name of Ends of sample coil L2 is connected with the Same Name of Ends of output inductor L1, and the different name end of sample coil L2 is connected with the different name end of output inductor L1 by resistance R.In dotted line frame, be output current sample circuit 10, L1 is the output inductor in output filter circuit 5.A point voltage is the reference ground of output voltage, and B point voltage is the equivalent resistance of output inductor L1 and the product that flows through the electric current of output inductor.B point voltage signal is exactly the output signal of output current sample circuit 10, and current regulating circuit 9 receives the output current sampled signal of output current sample circuit 10.
As shown in Figure 3, current regulating circuit comprises the amplifying circuit 11 being made up of amplifier U1, the comparison circuit 12 being made up of comparator U2; The in-phase input end of amplifier U1 is connected with the different name end of sample coil L2, and the output of comparator U2 is connected with output feedback control circuit.The output voltage signal of output current sample circuit 10 need to carry out signal amplification through the amplifying circuit 11 in current regulating circuit 9, and the output signal of amplifying circuit 11 is sent into the comparator forward end of comparison circuit 12 and compared with the reference signal of the comparator backward end of comparison circuit 12.In the time that the output signal voltage of amplifying circuit 11 is greater than the reference signal voltage of comparator backward end of comparison circuit 12, comparison circuit 12 is exported high level, and current regulating circuit 9 is exported high level; Otherwise, current regulating circuit 9 output low levels.Here, the conductor material of output inductor L1 is soft copper, and the temperature coefficient of copper is larger, and therefore, when in the constant situation of power source loads 6, the output signal voltage signal variation with temperature of amplifying circuit 11 and changing, is totally positive temperature characterisitic.So, also variation with temperature and changing of the signal voltage of the comparator backward end of comparison circuit 12, variation characteristic is consistent with the output signal voltage signal variation with temperature characteristic of amplifying circuit 11.
Current regulating circuit 9 receives the output signal of output current sample circuit 10, and this signal is exported to feedback control circuit 8 through sending into after conditioning, and then controls the driving signal output of Drive and Control Circuit 7.In the time there is not overload in power source loads 6, current regulating circuit 9 output low levels.The output signal of current regulating circuit 9 is inoperative to output feedback control circuit 8, and Drive and Control Circuit 7 is normally worked, the output voltage stabilization at power source loads 6 two ends.In the time there is larger overload in power source loads 6, reach the mistake flow point that Switching Power Supply arranges, current regulating circuit 9 is exported high level, makes the driving signal of Drive and Control Circuit 7 stop output by output feedback control circuit 8, finally makes the voltage drop at power source loads 6 two ends.
The operation principle of current foldback circuit: because the size of current sampling signal generally only has tens millivolts, therefore first realize the amplification of signal through amplifier U1.Current sampling signal after amplifier U1 amplifies is input to the forward end of comparator U2, and the magnitude of voltage of itself and comparator U2 backward end is compared, and when power supply is normally worked, comparator does not overturn; When load current reaches over-current protection point (be assumed to be maximum load current 120%), comparator overturns, and now, U2 is output as high level.U3 is feedback comparator.In the time of U2 output high level, the reference voltage of U3 will be dragged down, and makes output voltage sampled signal be greater than reference voltage, and feedback comparator U3 output low level increases the On current of triode Q1; In the time that the On current of triode Q1 reaches 1mA, the elementary pulse width controller of power supply will stop exporting the two-way driving signal of half-bridge, and then output voltage is dragged down.In Fig. 3, signal amplification is exactly the inner actual circuit of current regulating circuit 9 with the circuit in two frames of signal comparison, and the circuit in figure after the output of U2 is output feedback control circuit (this control circuit is the conventional III type feedback compensation circuit of Switching Power Supply).
The present invention utilizes the specific rule between equivalent resistance and the output current of the output inductor L1 in output filter circuit 5 to carry out sample of signal, its advantage is that sample circuit almost can be accomplished no power waste, this has created certain condition for power-efficient improves, improve Switching Power Supply delivery efficiency, the line loss that has reduced circuit, antijamming capability is strong.Sample coil L2 is upper around output inductor L1, and both are wound on same magnetic core, and sample circuit device is less, and it is convenient to implement.In addition, 9, current regulating circuit need to solve temperature characterisitic and the matching problem thereof of the reference signal voltage of the comparator backward end of comparison circuit 12, just can obtain good over-flow protecting effect.In-55 DEG C～+ 125 DEG C temperature ranges, work, can reach in the time that power source loads 6 exceedes 1.4 times of nominal load, effectively carry out overcurrent protection, and product integrated level is high, good reliability.
Claims (4)
1. a protective circuit of switch power source, comprise input filter circuit, circuit for power conversion, high frequency transformer, output rectification circuit, output filter circuit, Drive and Control Circuit, output feedback control circuit, current foldback circuit, described output filter circuit comprises output inductor (L1), it is characterized in that: described current foldback circuit comprises current regulating circuit and output current sample circuit; Described input filter circuit is connected with the output of described Drive and Control Circuit, the input of described high frequency transformer respectively via described circuit for power conversion; The input of described Drive and Control Circuit is connected with the output of the output of described input filter circuit, described output feedback control circuit; The output of described high frequency transformer is connected with power source loads via described output rectification circuit, output filter circuit; The output of described output filter circuit is connected with the input of output current sample circuit, the input of described output feedback control circuit is connected with the output of current regulating circuit, the output of output filter circuit, and the input of described current regulating circuit is connected with the output of described output current sample circuit.
2. a kind of protective circuit of switch power source according to claim 1, is characterized in that: described output current sample circuit is made up of sample coil (L2) and resistance (R); Described sample coil (L2) and output inductor (L1) and be wound on same magnetic core, the Same Name of Ends of sample coil (L2) is connected with the Same Name of Ends of output inductor (L1), and the different name end of sample coil (L2) is connected with the different name end of output inductor (L1) by resistance (R).
3. a kind of protective circuit of switch power source according to claim 1, is characterized in that: described current regulating circuit comprises the amplifying circuit (11) being made up of amplifier (U1), the comparison circuit (12) being made up of comparator (U2); The in-phase input end of described amplifier (U1) is connected with the different name end of sample coil (L2), and the output of described comparator (U2) is connected with output feedback control circuit.
4. a protective circuit of switch power source control method, is characterized in that, comprise the steps,
A: current sampling signal is realized to signal through operational amplifier (U1) and amplify;
B: the current sampling signal after operational amplifier U1 amplifies is input to the forward end of comparator (U2), the magnitude of voltage of itself and comparator (U2) backward end is compared, in the time that power supply is normally worked, comparator (U2) does not overturn; When load current reaches over-current protection point, comparator (U2) overturns, and now, (U2) is output as high level;
C: comparator (U2) output signal is sent to the feedback comparator (U3) in output feedback control circuit, in the time of (U2) output high level, (U3) reference voltage is dragged down, output voltage sampled signal is greater than reference voltage, feedback comparator (U3) output low level, the On current of triode (Q1) increases; In the time that the On current of triode (Q1) reaches 1mA, the elementary pulse width controller of power supply stops exporting half-bridge two-way and drives signal, and output voltage is dragged down.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410182577.9A CN103944147B (en) | 2014-05-04 | 2014-05-04 | A kind of protective circuit of switch power source and its control method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410182577.9A CN103944147B (en) | 2014-05-04 | 2014-05-04 | A kind of protective circuit of switch power source and its control method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN103944147A true CN103944147A (en) | 2014-07-23 |
| CN103944147B CN103944147B (en) | 2017-06-20 |
Family
ID=51191697
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201410182577.9A Active CN103944147B (en) | 2014-05-04 | 2014-05-04 | A kind of protective circuit of switch power source and its control method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN103944147B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105048774A (en) * | 2015-08-09 | 2015-11-11 | 安徽普为智能科技有限责任公司 | High-power switch power supply circuit |
| CN105048781A (en) * | 2015-08-09 | 2015-11-11 | 安徽普为智能科技有限责任公司 | Control method for switching power supply circuit |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3733536A (en) * | 1972-06-05 | 1973-05-15 | Ibm | Current sensor for low pass filter |
| CN1578088A (en) * | 2003-07-22 | 2005-02-09 | 夏普株式会社 | DC regulated power supply |
| CN1794553A (en) * | 2005-11-28 | 2006-06-28 | 广州电器科学研究院 | Digitalization high frequency soft switch electroplating power supply |
| CN101834536A (en) * | 2010-05-18 | 2010-09-15 | 天宝电子（惠州）有限公司 | Phase-shift energy-saving circuit controlled by current |
| CN101846702A (en) * | 2010-05-10 | 2010-09-29 | 伊博电源（杭州）有限公司 | Inductive current detection circuit |
| CN203826929U (en) * | 2014-05-04 | 2014-09-10 | 中国电子科技集团公司第四十三研究所 | A switch power supply protection circuit |
-
2014
- 2014-05-04 CN CN201410182577.9A patent/CN103944147B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3733536A (en) * | 1972-06-05 | 1973-05-15 | Ibm | Current sensor for low pass filter |
| CN1578088A (en) * | 2003-07-22 | 2005-02-09 | 夏普株式会社 | DC regulated power supply |
| CN1794553A (en) * | 2005-11-28 | 2006-06-28 | 广州电器科学研究院 | Digitalization high frequency soft switch electroplating power supply |
| CN101846702A (en) * | 2010-05-10 | 2010-09-29 | 伊博电源（杭州）有限公司 | Inductive current detection circuit |
| CN101834536A (en) * | 2010-05-18 | 2010-09-15 | 天宝电子（惠州）有限公司 | Phase-shift energy-saving circuit controlled by current |
| CN203826929U (en) * | 2014-05-04 | 2014-09-10 | 中国电子科技集团公司第四十三研究所 | A switch power supply protection circuit |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105048774A (en) * | 2015-08-09 | 2015-11-11 | 安徽普为智能科技有限责任公司 | High-power switch power supply circuit |
| CN105048781A (en) * | 2015-08-09 | 2015-11-11 | 安徽普为智能科技有限责任公司 | Control method for switching power supply circuit |
Also Published As
| Publication number | Publication date |
|---|---|
| CN103944147B (en) | 2017-06-20 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN206506286U (en) | A kind of Switching Power Supply current foldback circuit | |
| CN201887469U (en) | Over-voltage protection circuit for radio frequency power amplifier | |
| CN202384752U (en) | Switching power supply overcurrent protection circuit | |
| CN208753975U (en) | A kind of current foldback circuit and the Switching Power Supply comprising the circuit | |
| CN108173425A (en) | A kind of start-up circuit | |
| CN103533707B (en) | Voltage-stabilization dimmable LED (light emitting diode) driving power supply circuit | |
| CN109088396A (en) | A kind of current foldback circuit and the Switching Power Supply comprising the circuit | |
| CN207069897U (en) | Start-up circuit and inverse-excitation type switch power-supply | |
| CN104753330A (en) | Soft start method of power management | |
| CN203039343U (en) | Intrinsic safe over-current protection circuit | |
| CN101951135A (en) | Flyback switching power supply and over-current protection method thereof | |
| CN102497101A (en) | Self-excited Buck circuit | |
| CN103944147A (en) | Switching power protection circuit and control method thereof | |
| CN207819757U (en) | A kind of start-up circuit | |
| CN202424283U (en) | Charger based on single-chip three-end TOP22X integrated chip | |
| CN104393571A (en) | IGBT module over-current protection system | |
| CN204131385U (en) | Switching Power Supply current foldback circuit | |
| CN203826929U (en) | A switch power supply protection circuit | |
| CN107591778A (en) | A kind of current foldback circuit of self recovery | |
| CN204290729U (en) | A kind of based on Voltage loop feedback and the integral control circuit of load automatic current equalizing | |
| CN105071673B (en) | A kind of Switching Power Supply magnetic isolation feedback circuit based on a reference source 431 | |
| CN204424877U (en) | A kind of IGBT module Over Current Protection System | |
| CN105356425A (en) | Over-current turn-off circuit for direct-current solid-state power controller | |
| CN103137079A (en) | Constant current driving device of light-emitting diode (LED) backlight module | |
| CN103441672B (en) | A kind of self-excitation BUCK circuit based on auxiliary winding type sample circuit |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |