CN206041473U - DCDC is short -circuit protection circuit for converter - Google Patents
DCDC is short -circuit protection circuit for converter Download PDFInfo
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- CN206041473U CN206041473U CN201621093373.9U CN201621093373U CN206041473U CN 206041473 U CN206041473 U CN 206041473U CN 201621093373 U CN201621093373 U CN 201621093373U CN 206041473 U CN206041473 U CN 206041473U
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Abstract
The utility model discloses a DCDC is short -circuit protection circuit for converter, include: operational amplifier U1 and triode P1, operational amplifier U1's reference edge connecting resistance R1, resistance R2 and electric capacity C1, resistance R2 and electric capacity C1's other end ground connection, another termination preceding stage sampling port of resistance R1, operational amplifier U1's output connect triode P1's the b utmost point and resistance R3, triode P1's c utmost point ground connection, triode P1's the e utmost point and another termination messenger of resistance R3 can hold or the preceding stage forbids holding. The utility model provides a current short -circuit protection circuit line structure is complicated, the big scheduling problem in equipment space, is a novel short -circuit protection circuit, and the advantage is simple, the easily equipment of circuit.
Description
【Technical field】
The utility model designs DC/DC converter technical fields, and more particularly to a kind of DC/DC is sampled with short-circuit protection and controlled
Circuit processed.
【Background technology】
Short-circuit protection circuit in DC/DC converters has many kinds, different by sample mode, can be divided into voltage sample and
Two class of current sample.
The typical structure of voltage sample short-circuit protection is to increase an assists winding, i.e. voltage induced winding on the transformer
Sampled, winding T1 as shown in Figure 1.When short circuit occurs in circuit, power output becomes big, and input current increases, sampling
Winding T1 induced voltages are more negative.Circuit carries out rectifying and wave-filtering by D8 and C13 to induced voltage.Resistance R27 and R28 is carried out to which
The negative input end of error amplifier U2B is input to after partial pressure, and now error amplifier is output as high level.The high level passes through
D12 is connected to the positive input terminal of hysteresis comparator U2A so as to export high level, and the positive input terminal of U2B is moved to by metal-oxide-semiconductor Q4 conductings
Ground, i.e. U2B are output as low level, and circuit quits work.Electric capacity C20 plays a part of to keep voltage.After circuit quits work,
C20 is slowly discharged by resistance R18.When lower threshold voltage of the voltage less than U2A, which is output as low level, and metal-oxide-semiconductor Q4 is closed
Close, U2B recovers normal, circuit restarting.At interval of a period of time, circuit recovers output, if output is also in short-circuit shape
State, circuit will again enter protection quickly, until detect circuit output it is normal till.It is this to protect protection of also referred to as " having the hiccups ".
At this moment circuit is only existed in and recovers protection process and detection process, therefore circuit average power consumption very little.
Current sample short-circuit protection circuit Typical Route is as shown in Figure 2.By sampling resistor RS1, output current is converted
Sampled for voltage.During the output terminal shortcircuit of circuit, output current increase, the voltage increase at RS1 two ends, i.e. error amplifier
The negative input end of U1 becomes big, and its output end is low level, and diode D1 conductings, feedback signal are delivered to prime by optocoupler PC1,
Raise feedback compensation terminal (COMP ends) voltage of PWM controller, output end (OUT terminal) is output as low level, i.e. switching tube Q1
It is not turned on, circuit enters protected mode.This protection circuit sampling is output current, it is possible to accurately arrange overcurrent protection
Point, for example, output current is 2.4A, the current-limiting points of output current can be set to 2.6A.
In existing DC/DC converters, short-circuit protection circuit respectively has pluses and minuses in performance, but they have one it is common
Shortcoming, i.e. line construction are complicated, take up room larger in hydrid integrated circuit assembling.When DC/DC converter assembling spaces have
In limited time, existing short-circuit protection circuit is not just applied to.
【Utility model content】
For solving the problems such as existing short-circuit protection circuit line construction is complicated, component number is more, the utility model is provided
A kind of novel short-circuit protection circuit, advantage are that circuit is simple, component number is few.
The utility model is achieved through the following technical solutions：
A kind of DC/DC converters short-circuit protection circuit, including：Operational amplifier U1 and triode P1；Described computing
The reference edge connection resistance R1 of amplifier U1, the other end ground connection of resistance R2 and electric capacity C1, resistance R2 and electric capacity C1, resistance R1's
Another termination prime sample port, the b poles of the output end connecting triode P1 of operational amplifier U1 and resistance R3, triode P1's
C poles are grounded, and another termination Enable Pin or prime of the e poles of triode P1 and resistance R3 forbid end.
Described operational amplifier U1 is TL431 type operational amplifiers.
Described sample port is connected with the feedback compensation terminal of the PWM controller in DC/DC converters.
Described DC/DC converters include：PWM controller, input filter circuit, output filter circuit, feedback op are put
Big circuit, transformer；Primary coil one end of transformer T1 is connected with dc source by input filter circuit, and the other end passes through
VDMOS pipes are connected to ground, and the output end of PWM controller is connected to the grid of VDMOS pipes, the secondary coil output electricity of transformer T1
Pressure filtered circuit output again Jing after diode rectification, after the sampled error of output voltage is amplified, again Jing isolation be transferred to PWM controls
Device processed, controls the dutycycle of VDMOS pipe driving pulses；Primary coil one end of transformer T2 is connected with the feedback end of PWM controller
Connect, the secondary coil Jing feedback ops amplifying circuit of transformer T2 is connected with the output end of DC/DC converters；Described short circuit guarantor
Protection circuit is connected with the feedback compensation terminal of PWM controller.
Described DC/DC converters are single ended topology, with prime prohibiting function.
Described PWM controller is UC1843 chips.PWM controller possesses feedback compensation terminal, can be adopted by the exit
Collection DC/DC output short-circuits, over-current signal.
Relative to prior art, the utility model has advantages below：
The utility model is a kind of simple short-circuit protection circuit of line construction, relative to existing complicated circuit construction,
The utility model is only made up of 6 components and parts, with simple structure and account for assembling area it is few the features such as, and be capable of achieving adopting for circuit
Sample, compare and protect etc. function.
As a result the utility model shows to realize DC/DC converter circuits by the application in DC/DC converters
Short-circuit protection.The effect of existing short-circuit protection circuit is reached.
【Description of the drawings】
The voltage sample short-circuit protection circuit of Fig. 1 prior arts；
The current sample short-circuit protection circuit of Fig. 2 prior arts；
The structure chart of Fig. 3 the utility model short-circuit protection circuits；
The exemplary application map in DC/DC converters of Fig. 4 the utility model short-circuit protection circuits.
【Specific embodiment】
Below in conjunction with the accompanying drawings, specific embodiment of the present utility model is described in detail, but the utility model is not limited
In the embodiment.In order that the public has to the utility model thoroughly understand, in following the utility model preferably applies example in detail
Illustrate concrete details.
The utility model is related to the design of the short-circuit protection circuit for PWM (pulse width modulation) controller UC1843.
A kind of DC/DC converters short-circuit protection circuit of the present utility model, as shown in figure 3, including operational amplifier
TL431 (U1), resistance (R1, R2, R3), electric capacity (C1) and PNP triode (P1).8 pin connecting resistance R1, R2 of operational amplifier U1
And C1.The other end ground connection of resistance R2 and C1,01 port of another termination of resistance R1.The b poles of the output termination P1 of U1 and resistance
R3.The c poles ground connection of P1.02 port of another termination of the e poles of P1 and resistance R3.01 port is prime sampling end, and 02 port is to make
Energy end or prime forbid end.
Specifically protected mode is：Sampling end 01 carries out the reference edge (8 pin) that partial pressure is followed by U1 by resistance R1 and R2.
During DC/DC converter normal works, the voltage of the point is less than 2.5V, and 1 pin of output end of operational amplifier U1 is high level, and P1 cuts
Only, end 02 is forbidden not work to Enable Pin or prime.When the output terminal shortcircuit of DC/DC converters, the voltage liter of 01 port
8 pin voltages of height, i.e. U1 be higher than 2.5V so that the output (1 pin) of U1 be low level, P1 conducting, 02 end is made down for low level
Circuit quits work, and realizes protection.The low level of U1 outputs turns on P1, forms the discharge loop of Enable Pin, prevents U1 from having greatly
Electric current passes through, and causes to burn out.Wherein after circuit forbids protection, whole circuit quits work, and the wherein electric capacity of C1 is put by R2
Electricity, when the tension discharge of C1 is to less than 2.5V, the 1 pin output high level of U1, P1 cut-offs, 02 port recover normal voltage, electricity
Road is started working again, as circuit is still in short-circuit condition, detects short circuit, and circuit is forbidden again, and circuit is so entered " to be beaten
The state that belch " is protected.Electric capacity C1 can be with the protection period of adjustment circuit.R3 is the current-limiting resistance of U1.
The concrete circuit of the utility model practical application is as shown in figure 4, a kind of DC/DC converters of the present utility model, bag
Include：PWM controller, input filter circuit, output filter circuit, feedback op amplifying circuit, transformer and claims 1 to 3
Short-circuit protection circuit described in any one；Primary coil one end of transformer T1 is connected with dc source by input filter circuit
Connect, the other end is connected to ground by VDMOS pipes, the output end of PWM controller is connected to the grid of VDMOS, and transformer T1's is secondary
Level coil output voltage filtered circuit output again Jing after diode rectification.After the sampled error of output voltage is amplified, again Jing every
From PWM controller is transferred to, the dutycycle of VDMOS pipe driving pulses is controlled, so as to realize output voltage stabilization.Transformer T2's
Primary coil one end is connected with the feedback end of PWM controller, the secondary coil Jing feedback ops amplifying circuit of transformer T2 and DC/
The output end connection of DC converters；Described short-circuit protection circuit is connected with the feedback compensation terminal of PWM controller.
The protection circuit is applied to input voltage 100V, output voltage 5V, and power output is in the DC/DC converters of 5W.
01 port of sampling end connects the feedback compensation terminal of PWM controller, and during DC/DC converter normal works, the voltage of sampled point is 2.5V,
Jing after resistance R1 and R2 partial pressure, the reference voltage terminal (8 pin) of U1 is 2.42V, less than reference voltage 2.5V.The negative electrode (1 pin) of U1
For high level 10.8V, 02 port of Enable Pin is forbidden for low level.When the output terminal shortcircuit of DC/DC converters, PWM controller
The level of feedback compensation terminal is raised, and is 2.56V, i.e., the reference voltage terminal of U1 (8 pin) is raised so that the negative electrode (1 pin) of U1 is low
Level 0.5V.The low level is applied to 02 port, drags down the supply line of circuit, i.e. circuit control loop quits work, and realizes
Protection.When electric capacity C1 is discharged into less than 2.5V, 6 pin of operational amplifier U1 are high level, and the level rising of 02 port, circuit are opened
Beginning work.As circuit output end is still short-circuit condition, circuit is again into the protection stage.The period of change of 02 port level is
The protection detection cycle of circuit.
The short-circuit dissipation of its test is for example shown in table 1 (three warm test datas).
Table 1
| -55℃ | 25℃ | 125℃ | |
| Short-circuit dissipation (W) | 0.81 | 1.04 | 2.42 |
As can be seen from Table 1, the utility model technology realizes the function of its short-circuit protection in DC/DC converters.
Novel short-circuit protection circuit solutions set forth above have been put into the military DC/DC converters of 100V series
In design, the short-circuit protection of circuit can be realized.
More than, preferred embodiment only of the present utility model is not limited only to practical range of the present utility model, Fan Yiben
Equivalence changes and modification that the content of utility model patent scope is done, all should be technology category of the present utility model.
Claims (5)
1. a kind of DC/DC converters short-circuit protection circuit, it is characterised in that include：Operational amplifier U1 and triode P1；Institute
The reference edge connection resistance R1 of the operational amplifier U1 for stating, the other end ground connection of resistance R2 and electric capacity C1, resistance R2 and electric capacity C1,
Another termination prime sample port of resistance R1, the b poles of the output end connecting triode P1 of operational amplifier U1 and resistance R3, three
Another termination Enable Pin or prime of the c poles ground connection of pole pipe P1, the e poles of triode P1 and resistance R3 forbids end.
2. a kind of DC/DC converters short-circuit protection circuit according to claim 1, it is characterised in that described computing
Amplifier U1 is TL431 type operational amplifiers.
3. a kind of DC/DC converters short-circuit protection circuit according to claim 1, it is characterised in that described sampling
Port is connected with the feedback compensation terminal of the PWM controller in DC/DC converters.
4. a kind of DC/DC converters short-circuit protection circuit according to claim 3, it is characterised in that described DC/DC
Converter includes：PWM controller, input filter circuit, output filter circuit, feedback op amplifying circuit and transformer；Transformation
Primary coil one end of device T1 is connected with dc source by input filter circuit, and the other end is connected to ground by VDMOS pipes,
The output end of PWM controller is connected to the grid of VDMOS pipes, and the secondary coil output voltage of transformer T1 is Jing after diode rectification
Filtered circuit output again, after the sampled error of output voltage is amplified, again Jing isolation be transferred to PWM controller, control VDMOS pipes
The dutycycle of driving pulse；Primary coil one end of transformer T2 is connected with the feedback end of PWM controller, the secondary of transformer T2
Coil Jing feedback ops amplifying circuit is connected with the output end of DC/DC converters.
5. a kind of DC/DC converters short-circuit protection circuit according to claim 3, it is characterised in that described PWM controls
Device processed is UC1843 chips.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201621093373.9U CN206041473U (en) | 2016-09-29 | 2016-09-29 | DCDC is short -circuit protection circuit for converter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201621093373.9U CN206041473U (en) | 2016-09-29 | 2016-09-29 | DCDC is short -circuit protection circuit for converter |
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| CN206041473U true CN206041473U (en) | 2017-03-22 |
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| CN201621093373.9U Active CN206041473U (en) | 2016-09-29 | 2016-09-29 | DCDC is short -circuit protection circuit for converter |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108780990A (en) * | 2017-09-06 | 2018-11-09 | 深圳和而泰智能控制股份有限公司 | Device for power switching current foldback circuit and motor driven systems, electric system |
| CN111525515A (en) * | 2020-04-13 | 2020-08-11 | 欣旺达电子股份有限公司 | Short circuit/overload protection circuit and method for DC/DC power supply module |
| CN114879803A (en) * | 2022-05-24 | 2022-08-09 | 西安微电子技术研究所 | Current-limiting protection circuit structure of LDO (low dropout regulator) |
-
2016
- 2016-09-29 CN CN201621093373.9U patent/CN206041473U/en active Active
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108780990A (en) * | 2017-09-06 | 2018-11-09 | 深圳和而泰智能控制股份有限公司 | Device for power switching current foldback circuit and motor driven systems, electric system |
| WO2019047079A1 (en) * | 2017-09-06 | 2019-03-14 | 深圳和而泰智能控制股份有限公司 | Power switching component overcurrent protection circuit, motor driving system, and motor system |
| CN111525515A (en) * | 2020-04-13 | 2020-08-11 | 欣旺达电子股份有限公司 | Short circuit/overload protection circuit and method for DC/DC power supply module |
| CN114879803A (en) * | 2022-05-24 | 2022-08-09 | 西安微电子技术研究所 | Current-limiting protection circuit structure of LDO (low dropout regulator) |
| CN114879803B (en) * | 2022-05-24 | 2023-07-04 | 西安微电子技术研究所 | Current-limiting protection circuit structure of LDO |
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