CN102035182A - Universal type short circuit isolation protection circuit for flyback switching power supply - Google Patents
Universal type short circuit isolation protection circuit for flyback switching power supply Download PDFInfo
- Publication number
- CN102035182A CN102035182A CN2010105650811A CN201010565081A CN102035182A CN 102035182 A CN102035182 A CN 102035182A CN 2010105650811 A CN2010105650811 A CN 2010105650811A CN 201010565081 A CN201010565081 A CN 201010565081A CN 102035182 A CN102035182 A CN 102035182A
- Authority
- CN
- China
- Prior art keywords
- power supply
- resistance
- circuit
- output
- module
- 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.)
- Pending
Links
Images
Landscapes
- Dc-Dc Converters (AREA)
Abstract
The invention discloses a universal type short circuit isolation protection circuit for a flyback switching power supply, comprising an isolation sampling module, a voltage dividing delaying module and a discharging module. The voltage at the output end of the flyback switching power supply is directly used as a signal for triggering short circuit protection, and thus the short circuit state of a circuit can be accurately responded. The short circuit protection circuit of the invention achieves the aims of rapidly switching off a power supply chip when outputting short circuit and preventing the power supply chip from restarting through controlling the power supply voltage of the power supply chip, therefore, the protection circuit has no special base pin requirement on the power supply chip and has high universality. In addition, the invention has the advantages of simple structure, convenience for debugging, low power consumption, low cost and the like.
Description
Technical field
The present invention relates to a kind of short-circuit protection circuit, be specifically related to the universal isolation short-circuit protection circuit of a kind of reverse exciting switching voltage regulator.
Background technology
Along with reverse exciting switching voltage regulator uses more and more widely, the user is also more and more higher to its reliability requirement.This will negate exciting switching voltage regulator under various abnormal conditions, can protect the safety of self and load equipment.Wherein, short-circuit protection is a very important defencive function of Switching Power Supply.During the output short-circuit of reverse exciting switching voltage regulator, power circuit has following feature: 1. the electric current on the output loop is very big, and the power device heating is serious; 2. output end voltage is very little, and is almost nil, and the curtage feedback control loop can't operate as normal.3. power switch conducting duty ratio increases, and the primary side current peak increases.
The short-circuit protection method that reverse exciting switching voltage regulator is commonly used is to utilize special short-circuit protection circuit; monitor and whether have the short circuit feature in the power circuit; if the short circuit feature, then short-circuit protection circuit sends short circuit generation signal to power supply control chip, thereby power supply control chip is quit work.It is very fast to the response ratio of short circuit that chip turn-offs method, and have the advantages that the outage back is recovered automatically.
At present the working mechanism of short-circuit protection circuit is as follows: failing to be convened for lack of a quorum according to the peak electricity of input side power switch when the output short circuit becomes big this phenomenon, when the peak current that detects power switch surpasses a certain threshold value, promptly is judged as output short-circuit.But when the reverse exciting switching voltage regulator operate as normal, if when input voltage or load variations, the peak current of power switch also can change.When input voltage or load appearance sudden change (still in working range), the peak current of power switch might rise to the protection threshold value, and this will cause the misoperation of short-circuit protection circuit.
In addition, the output of short-circuit protection circuit all is the some pins with specific function that are connected on power supply chip at present, as chip remote control pin (on/off end).When short-circuit state occurring, short-circuit protection circuit reaches the purpose of powered-down chip by to the specific function pin of power supply output height digital signal or reduce the voltage of this pin.Because a lot of power supply control chips do not have remote control end (on/off end), be connected to the short-circuit protection circuit of chip remote control pin for output, the scope of application has certain limitation in fact.
Summary of the invention
Purpose of the present invention is intended to solve the technological deficiency of existing reverse exciting switching voltage regulator short-circuit protection circuit, particularly solves the problem that may cause the short circuit current misoperation in the indirect short trouble monitoring scheme and the short-circuit protection circuit problem to different reverse exciting switching voltage regulator chip bad adaptability.
In order to achieve the above object; the invention provides the universal isolation short-circuit protection circuit of a kind of reverse exciting switching voltage regulator; this short-circuit protection circuit is directly measured output voltage and is changed, and realizes short-circuit protection by the supply power voltage of control power supply chip, can be used in most of reverse exciting switching voltage regulator schemes.As shown in Figure 1, described short-circuit protection circuit is formed by isolating sampling module, dividing potential drop time delay module and earial drainage module.The output voltage signal that wherein said isolation sampling module is directly gathered, and the mode by isolation coupling obtain isolating current signal; Described dividing potential drop time delay module changes described isolation current signal into the earial drainage control signal; Described earial drainage module produces leakage current under the control of described earial drainage control signal, the supply power voltage of power supply chip is controlled.
The universal isolation short-circuit protection circuit of reverse exciting switching voltage regulator of the present invention comprises following concrete isolation sampling module, dividing potential drop time delay module and earial drainage module, as shown in Figure 2.
Described earial drainage module is made up of with NPN type triode Q1 resistance R 1: the b end of resistance R 1 links to each other with the collector electrode of triode Q1; The a end of resistance R 1 links to each other with the anode of power supply chip power supply electric capacity; The emitter of triode Q1 links to each other with the negative terminal of power supply chip power supply electric capacity.
Described dividing potential drop time delay module is made up of resistance R 2, resistance R 3 and capacitor C 1: resistance R 2 is connected in series with resistance R 3, and the d end of resistance R 2 joins with the e end of resistance R 3; Capacitor C 1 is connected in parallel with resistance R 3, the e end of the positive terminating resistor R3 of capacitor C 1, the f end of the negative terminal connecting resistance R3 of capacitor C 1; The a end of resistance R 1 joins in the c end of resistance R 2 and the described earial drainage module; The base stage of triode Q1 is joined in the e end of resistance R 3 and the described earial drainage module.
Described isolation sampling module is made up of optocoupler U1 and resistance R 4: the h end of resistance R 4 joins with the positive pole of the input diode of optocoupler U1; The g end of resistance R 4 joins with the anode of reverse exciting switching voltage regulator output; The negative terminal of the negative pole of the input diode of optocoupler U1 and reverse exciting switching voltage regulator output joins; The anode of capacitor C 1 joins in the anode of the output of optocoupler U1 and the described dividing potential drop time delay module; The negative terminal of capacitor C 1 joins in the negative terminal of the output of optocoupler U1 and the described dividing potential drop time delay module.
The operation principle of the universal isolation short-circuit protection circuit of reverse exciting switching voltage regulator of the present invention is as follows: the generation signal code of this output voltage of the output voltage V o of power supply on resistance R 4 and optocoupler U1 input diode, this signal code is isolated electric current in the coupling output of optocoupler U1.When the power supply operate as normal, the output voltage of power supply is higher, and it is also bigger then to isolate electric current.The power input that this isolation electric current is the dividing potential drop time delay module (the Vcc end in the accompanying drawing 2) flows out through resistance R 2, and the isolation electric current is big, and the pressure drop on the R2 is just high, and then the voltage on the resistance R 3 (voltage on the capacitor C 1) can be dragged down in the dividing potential drop time delay network.When output voltage was in normal range (NR), each parameter of rational Match circuit made that the basic emitter-base bandgap grading conducting voltage of triode Q1 is low in the voltage ratio at resistance R 3 two ends thereby the earial drainage module, and triode Q1 does not have base current, not conducting of triode Q1.Then chip power supply electric capacity by triode Q1 discharge, can not keep, the power supply chip operate as normal by the voltage of chip power supply electric capacity.When the output short-circuit of reverse exciting switching voltage regulator or output end voltage were very low, output voltage V o was very little, and the signal code that produces on the optocoupler U1 input diode is just very little, thereby the isolation electric current of optocoupler U1 output is also very little.When the isolation electric current is very little, to the almost not influence of dividing potential drop of each resistance in the dividing potential drop time delay module.This moment is pressure drop meeting reduction on the resistance R 2 in the dividing potential drop time delay module, and the pressure drop meeting on the resistance R 3 is risen.When the voltage on the resistance R 3 rises to the basic emitter-base bandgap grading conducting voltage of triode Q1, triode Q1 conducting, the earial drainage module is to the chip power supply capacitor discharge, and when the power supply capacitance voltage was reduced to the shutoff voltage of power supply chip, chip turn-offed.
After chip turn-offed, the start-up circuit of chip can continue to charge to chip power supply electric capacity.Ratio by resistance R 2 and R3 in the appropriate design dividing potential drop time delay module, after the voltage of assurance chip power supply electric capacity drops to the chip shutoff voltage, pressure drop on the resistance R 3 still can be kept triode Q1 conducting, and the electric current that the discharging current on the earial drainage module 300 is provided more than or equal to the chip enable circuit, then power supply chip will remain on off state always.After the short-circuit conditions of power output end was got rid of, input that should deenergization waited for that capacitor C 1 finishes by the R3 discharge, can restart.When power supply restarted, because the dividing potential drop time delay module has certain charging interval, so not conducting at once of triode Q1, the power supply of power supply chip was unaffected.If the circuit output end state just often, output end voltage Vo will very fast foundation, and short-circuit protection circuit then of the present invention is failure to actuate; If after charging interval of dividing potential drop time delay module arrived, output end voltage Vo did not also reach normal value, then think circuit abnormality (short circuit or under-voltage), short-circuit protection circuit action of the present invention drags down chip power supply voltage, and power supply chip is closed.
The selected rule of each component parameters in the circuit theory diagrams of accompanying drawing 2: each parametric representation: v in the formula hereinafter
ShutBe the shutoff voltage value of power supply chip, v
OnFor power supply chip at circuit working just often, the magnitude of voltage of chip power supply electric capacity.h
1Be the current amplification factor of triode Q1, v
bBasic emitter-base bandgap grading conducting voltage for triode.h
2Be the current transfer ratio of optocoupler U1, v
fConducting forward voltage drop for the input diode of optocoupler U1.v
oThe lower limit of output voltage during for the power supply operate as normal.i
4For flowing through the electric current of resistance R 4, i
sBe the output current of optocoupler U1, i
1For flowing through the electric current of resistance R 1, i
2For flowing through the electric current of resistance R 2, i
3For flowing through the electric current of resistance R 3, i
bBase current for triode Q1.I
ChBe the charging current of power initiation circuit to chip power supply electric capacity.
Each capacitance-resistance value among Fig. 2, the subscript that all adopts corresponding alphabetical small letter to add corresponding sequence number is represented hereinafter, as r
1The value of expression R1, c
1The value of expression C1 etc.
Rule 1. is v at output voltage
oThe time, should guarantee that short-circuit protection circuit do not work.Then the relevant parameters relation should be shown in formula (1) and formula (2).
Described regular 1 implication is rationally to adjust each component parameters, the feasible current i of calculating by (1) formula
2, i
3And i
S, the relation between them should satisfy (2) formula.
i
2≤i
3+i
s (2)
Described regular 2 implication is rationally to adjust each component parameters, the feasible i that calculates by (3) formula
1Should satisfy (4) formula and (5) formula.
i
b＝i
2-i
3 
i
1≥i
ch (4)
Reverse exciting switching voltage regulator short-circuit protection circuit provided by the invention has been realized the output voltage of direct detection reverse exciting switching voltage regulator, can respond output exactly and get short-circuit conditions; In addition; reverse exciting switching voltage regulator short-circuit protection circuit provided by the invention is realized coming the powered-down chip by the supply power voltage that drags down power supply chip; do not have the specific pin requirement for power supply chip, therefore have very strong versatility, can be conveniently used in the various reverse exciting switching voltage regulator schemes.In addition, it is little that short-circuit protection circuit of the present invention also has power consumption, and debugging is convenient, and the electronic component number is few, and is simple in structure, low cost and other advantages.
Description of drawings
The structure principle chart of the universal isolation short-circuit protection circuit of Fig. 1 reverse exciting switching voltage regulator.
The circuit theory diagrams of the universal isolation short-circuit protection circuit of Fig. 2 reverse exciting switching voltage regulator.
Fig. 3 is the typical application circuit schematic diagram of circuit shown in Figure 2.
Embodiment
Accompanying drawing 3 has been showed the typical application circuit schematic diagram of short-circuit protection circuit provided by the present invention.It should be noted that for for the purpose of concise and to the point, only indicated the major part of circuit of reversed excitation among Fig. 3.
In the accompanying drawing 3 except short-circuit protection circuit part of the present invention; each components and parts of remainder are: U2 is a power supply control chip; T1 is anti-violent change depressor; Q2 is a power switch; D1, D2 are respectively chip power supply rectifier diode and output rectifier diode; C2 is the power supply electric capacity of chip, and C3, C4 are output capacitance, and R6 is the charging resistor of chip enable.When bold box was represented operate as normal, the voltage of circuit of reversed excitation or current sample network, this network can't operate as normal when output short-circuit.
The anti-input voltage that swashs power supply is 200V in the accompanying drawing 3, and output voltage range is 25V～35V, and output current is 2A.
The capacitance of capacitor C 2 is c
2=22uF, the resistance of resistance R 5 is r
5=300K Ω, the capacitance of output capacitance C3 and C4 are c
3=1000uF, c
4=1000uF.
The shutoff voltage v of power supply chip
Shut=10V, power supply chip is at circuit voltage v
On=14V.
Selecting optocoupler U1 is PC817A.Optocoupler PC817A is at the current transfer ratio h that is input as about 100uA
2=0.1, the input diode conducting forward voltage drop v of optocoupler PC817A
f=1.1V.
Selecting triode Q1 is 2N3904.Triode 2N3904 is current amplification factor h about 10uA at base current
1=150, basic emitter-base bandgap grading conducting voltage v
b=0.65V.
According to circuit working principle described in the summary of the invention and parameter setting rule, the parameter that gets each element of circuit is specifically selected as follows:
| Label in the accompanying drawing 3 | Model or parameter |
| R1 | 10KΩ |
| R2 | 750KΩ |
| R3 | 130KΩ |
| R4 | 150KΩ |
| C1 | 10uF |
| Q1 | 2N3904 |
| U1 | PC817A |
Claims (1)
1. the universal isolation short-circuit protection circuit of reverse exciting switching voltage regulator is formed by isolating sampling module, dividing potential drop time delay module and earial drainage module, it is characterized in that:
Described earial drainage module is made up of resistance R 1 and NPN type triode Q1, wherein the b of resistance R 1 end links to each other with the collector electrode of NPN type triode Q1, the a end of resistance R 1 links to each other with the anode of power supply chip power supply electric capacity, and the emitter of triode Q1 links to each other with the negative terminal of power supply chip power supply electric capacity;
Described dividing potential drop time delay module is made up of resistance R 2, resistance R 3 and capacitor C 1, wherein resistance R 2 is connected in series with resistance R 3, the d end of resistance R 2 joins with the e end of resistance R 3, capacitor C 1 is connected in parallel with resistance R 3, the e end of the positive terminating resistor R3 of capacitor C 1, the f end of the negative terminal connecting resistance R3 of capacitor C 1, the c end of resistance R 2 joins with a end of resistance R 1, and the e end and the base stage of triode Q1 of resistance R 3 are joined;
Described isolation sampling module is made up of optocoupler U1 and resistance R 4, wherein the h of resistance R 4 end joins with the positive pole of the input diode of described optocoupler U1, the g end of resistance R 4 joins with the anode of reverse exciting switching voltage regulator output, the negative terminal of the negative pole of the input diode of optocoupler U1 and reverse exciting switching voltage regulator output joins, the anode of the anode of the output of optocoupler U1 and capacitor C 1 joins, and the negative terminal of the negative terminal of the output of optocoupler U1 and capacitor C 1 joins;
When the power output end short circuit, the output of optocoupler U1 in the described isolation sampling module is output current not, dividing potential drop on the resistance R 3 of described dividing potential drop time delay module makes the triode Q1 conducting in the described earial drainage module, described earial drainage module produces leakage current to the chip power supply capacitor discharge, the chip power supply capacitance voltage reduces, and power supply chip turn-offs; When power supply is exported just often, the output output current of optocoupler U1 in the described isolation sampling module, this output current drags down the dividing potential drop on the resistance R 3 of described dividing potential drop time delay module, triode Q1 in the described earial drainage module is turn-offed, then described earial drainage module is not to the chip power supply capacitor discharge, and power supply chip is working properly.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010105650811A CN102035182A (en) | 2010-11-26 | 2010-11-26 | Universal type short circuit isolation protection circuit for flyback switching power supply |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010105650811A CN102035182A (en) | 2010-11-26 | 2010-11-26 | Universal type short circuit isolation protection circuit for flyback switching power supply |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN102035182A true CN102035182A (en) | 2011-04-27 |
Family
ID=43887693
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2010105650811A Pending CN102035182A (en) | 2010-11-26 | 2010-11-26 | Universal type short circuit isolation protection circuit for flyback switching power supply |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN102035182A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103337839A (en) * | 2013-06-26 | 2013-10-02 | 国家电网公司 | PLC opto-isolator driving circuit and resistance loop device of MOS gate |
| WO2016090547A1 (en) * | 2014-12-09 | 2016-06-16 | 深圳市聚作照明股份有限公司 | Switch-mode power supply and short-circuit protection circuit thereof |
| CN108306254A (en) * | 2018-04-09 | 2018-07-20 | 广州金升阳科技有限公司 | A kind of isolation protective circuit and the Switching Power Supply comprising the circuit |
| CN110768532A (en) * | 2018-07-27 | 2020-02-07 | 比亚迪股份有限公司 | Power management device of turnout control chip and turnout control system |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2559152Y (en) * | 2002-07-05 | 2003-07-02 | 北京通力环电气股份有限公司 | Anti-excitation HF switch power output short-circuit protector |
| CN1773801A (en) * | 2005-08-12 | 2006-05-17 | 刘树林 | Switch supply source cut-off type output short-circuit protector |
| CN201063548Y (en) * | 2007-08-07 | 2008-05-21 | Bcd半导体制造有限公司 | Switch power supply and pulsewidth modulation controller thereof |
| US7379310B2 (en) * | 2004-04-23 | 2008-05-27 | Thomson Licensing | Over-voltage protection circuit for a switched mode power supply |
-
2010
- 2010-11-26 CN CN2010105650811A patent/CN102035182A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2559152Y (en) * | 2002-07-05 | 2003-07-02 | 北京通力环电气股份有限公司 | Anti-excitation HF switch power output short-circuit protector |
| US7379310B2 (en) * | 2004-04-23 | 2008-05-27 | Thomson Licensing | Over-voltage protection circuit for a switched mode power supply |
| CN1773801A (en) * | 2005-08-12 | 2006-05-17 | 刘树林 | Switch supply source cut-off type output short-circuit protector |
| CN201063548Y (en) * | 2007-08-07 | 2008-05-21 | Bcd半导体制造有限公司 | Switch power supply and pulsewidth modulation controller thereof |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103337839A (en) * | 2013-06-26 | 2013-10-02 | 国家电网公司 | PLC opto-isolator driving circuit and resistance loop device of MOS gate |
| WO2016090547A1 (en) * | 2014-12-09 | 2016-06-16 | 深圳市聚作照明股份有限公司 | Switch-mode power supply and short-circuit protection circuit thereof |
| CN108306254A (en) * | 2018-04-09 | 2018-07-20 | 广州金升阳科技有限公司 | A kind of isolation protective circuit and the Switching Power Supply comprising the circuit |
| CN110768532A (en) * | 2018-07-27 | 2020-02-07 | 比亚迪股份有限公司 | Power management device of turnout control chip and turnout control system |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN107222028B (en) | Power failure reporting implementation method and circuit for power consumption information acquisition equipment | |
| CN201682417U (en) | Power supply protection circuit based on super capacitor | |
| CN1909315B (en) | Multiple-output electric power and its overcurrent detecting and protecting method | |
| CN109638786B (en) | Photovoltaic module turn-off protection circuit and module turn-off device | |
| CN103606895B (en) | A kind of overvoltage turn-off protection circuit | |
| CN109342973B (en) | Direct current power supply input state monitoring circuit and system | |
| CN205141657U (en) | Input overvoltage crowbar | |
| CN104104067A (en) | Short circuit protection circuit | |
| CN116094143B (en) | Power voltage detecting system | |
| CN102035182A (en) | Universal type short circuit isolation protection circuit for flyback switching power supply | |
| CN104218531A (en) | Short circuit protecting circuit and method | |
| CN101727122B (en) | Quadratic linear power system latching preventing circuit for system level CMOS integrated circuit | |
| CN103677034A (en) | Standby circuit of household appliance and standby control method | |
| CN201142664Y (en) | Generator voltage regulator for multifunctional vehicle | |
| CN107733219A (en) | A kind of Switching Power Supply output soft start circuit | |
| CN102778849B (en) | Switching on and shutting down control circuit, electronic equipment and on-off control method | |
| CN202735879U (en) | Standby circuit of household appliances | |
| CN203086098U (en) | Relay protection power supply output sequential line | |
| CN203398768U (en) | Low-cost AC input overvoltage protection circuit and switching power supply | |
| CN101645672B (en) | Solar panel power supply system and start control method thereof | |
| CN207573234U (en) | A kind of Switching Power Supply output soft start circuit | |
| CN204068210U (en) | Short-circuit protection circuit | |
| CN203607824U (en) | Overvoltage turn-off protective circuit | |
| CN202872642U (en) | Multi-path output flyback power supply with output short-circuit protection function | |
| CN2730022Y (en) | Automatic recovery protection circuit type switch supply unit |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| WD01 | Invention patent application deemed withdrawn after publication |
Application publication date: 20110427 |
|
| WD01 | Invention patent application deemed withdrawn after publication |