CN204517374U - A kind of output short circuit protection circuit of BUCK converter - Google Patents
A kind of output short circuit protection circuit of BUCK converter Download PDFInfo
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- CN204517374U CN204517374U CN201520278071.8U CN201520278071U CN204517374U CN 204517374 U CN204517374 U CN 204517374U CN 201520278071 U CN201520278071 U CN 201520278071U CN 204517374 U CN204517374 U CN 204517374U
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Abstract
The utility model discloses a kind of output short circuit protection circuit of BUCK converter, comprise comparator U1, switching diode D2 and nonpolar electric capacity C2, and resistance R1, resistance R2, resistance R3, resistance R4 and resistance R5; The anode of switching diode D2 and one end of resistance R1 connect and are the input V-IN of output short circuit protection circuit; the negative electrode of switching diode D2 connects with one end of nonpolar electric capacity C2 and one end of resistance R3; the other end of resistance R1 is by resistance R2 ground connection; the other end ground connection of nonpolar electric capacity C2; the other end of resistance R3 connects with the inverting input of comparator U1; the link of resistance R1 and resistance R2 and one end of resistance R5 all connect with the in-phase input end of comparator U1, and the output of comparator U1 is the output V-OUT of output short circuit protection circuit.The utility model can realize formula short-circuit protection of having the hiccups, and has self-recovering function, practical.
Description
Technical field
The utility model relates to switch power technology field, especially relates to a kind of output short circuit protection circuit of BUCK converter.
Background technology
Along with the fast development of electronic technology, protective circuit of switch power source becomes a vital part in circuit design.At present, the protection scheme that power supply or Switching Power Supply are commonly used has a lot: (1) is divided into according to the difference of sampled signal: current mode protective circuit and voltage-type protective circuit.In general protective circuit, major part adopts current mode protective circuit, and the type needs current sampling resistor, and resistance can flow through very large electric current; according to little resistance current sampling resistor; then need signal to be carried out process, amplify, circuit can be made so complicated, increase cost.Also can adopt current sensor or Hall element etc. to carry out current sampling, but due to current sensor price higher, and many current sensors need another additional power source could normal work, and this makes again circuit structure complicated, and cost increases.And voltage-type protective circuit, without the need to sample rate current, only need sampled voltage, carrying out dividing potential drop by large valued resistor just can realize, and structure is simple, and power consumption is little, and cost is low.(2) according to being divided into the control of output current: current-limiting type protective circuit, the type that dams or the flow pattern protective circuit that subtracts, thoroughly turn-off type protective circuit and can the self-recovery protection circuit of thorough on-off switching tube.1. current-limiting type protective circuit is that output voltage declines and limited within the specific limits by output current when power output end overload or short circuit.The advantage of this protected mode is: protection range is large, and antijamming capability is strong, and its circuit is general comparatively simple, and after failture evacuation, power supply easily recovers.Shortcoming is: protection speed is slow, and during output short circuit protection, still have larger electric current to flow through, power consumption is large.2. the type that dams or subtract flow pattern protective circuit: when switch converters output overloading or short circuit, protective circuit is action immediately, and output current and voltage can be made to reduce rapidly.The advantage of this protective circuit is: protection act speed is fast, effective, power loss is little, is applicable to the power supply that power output is larger.Shortcoming is: this protective circuit more complicated, and circuit debugging is cumbersome, power supply not easily self-recoverage after failture evacuation.3. thorough turn-off type protective circuit, namely once after protective circuit action, even if overcurrent or short trouble are eliminated; power supply is still in off state always; must first power cutoff, restart system and just can resume work, circuit can not realize self-recoverage, cannot meet the requirement of intrinsic safety electric source.4. can the self-recovery protection circuit of thorough on-off switching tube, this kind of protective circuit needs current detection circuit, short circuit or composition such as overload decision circuitry, delay circuit etc. usually, and circuit is comparatively complicated; And general can recovery-type protective circuit after main circuit breaks down, although output voltage can be limited in lower scope, now electric current is very large, because Switching Power Supply is in fact also in work.Therefore, for the intrinsic safe explosion-proof power supply being applied to hazardous environment, the spark energy that short trouble produces is considerable, very possible ignites inflammable, explosion hazard gases and composition thereof, is difficult to realize intrinsic safety and exports.
Current China's coal-mine One's name is legion, gas explosion accident is of common occurrence, causes significant threat to the life security of the people.Therefore, a kind of voltage-type being applicable to risk environment formula output short circuit protection circuit of having the hiccups is designed significant.
Utility model content
Technical problem to be solved in the utility model is for above-mentioned deficiency of the prior art; a kind of output short circuit protection circuit of BUCK converter is provided, its circuit structure is simple, with low cost, simple operation, the formula short-circuit protection that can realize having the hiccups, have self-recovering function, practical, be convenient to promote the use of.
For solving the problems of the technologies described above, the technical solution adopted in the utility model is: a kind of output short circuit protection circuit of BUCK converter, it is characterized in that: comprise comparator U1, switching diode D2 and nonpolar electric capacity C2, and resistance R1, resistance R2, resistance R3, resistance R4 and resistance R5, the anode of described switching diode D2 and one end of resistance R1 connect and are the input V-IN of described output short circuit protection circuit, the input V-IN of described output short circuit protection circuit connects with the cathode voltage output of BUCK converter, the negative electrode of described switching diode D2 connects with one end of nonpolar electric capacity C2 and one end of resistance R3, the other end of described resistance R1 is by resistance R2 ground connection, the other end ground connection of described nonpolar electric capacity C2, the other end of described resistance R3 connects with the inverting input of comparator U1, and by resistance R4 ground connection, the link of described resistance R1 and resistance R2 and one end of resistance R5 all connect with the in-phase input end of comparator U1, the power end of described comparator U1 and the other end of resistance R5 all connect with the output VCC of power supply, the earth terminal ground connection of described comparator U1, the output of described comparator U1 is the output V-OUT of described output short circuit protection circuit, the output V-OUT of described output short circuit protection circuit connects with the input of PWM controlling and driving circuits.
The output short circuit protection circuit of above-mentioned a kind of BUCK converter, is characterized in that: described comparator U1 is made up of chip LM393, and the output of described comparator U1 is connected with the output VCC of power supply by resistance R6.
The output short circuit protection circuit of above-mentioned a kind of BUCK converter, it is characterized in that: described BUCK converter comprises PMOS switch pipe VT1, inductance L 1, switching diode D1 and polar capacitor C1, the grid of described PMOS switch pipe VT1 connects with the output of PWM controlling and driving circuits, the drain electrode of described PMOS switch pipe VT1 is the voltage input end Vi of BUCK converter, the source electrode of described PMOS switch pipe connects with one end of the negative electrode of switching diode D1 and inductance L 1, the other end of described inductance L 1 connect with the positive pole of polar capacitor C1 and for BUCK converter cathode voltage output end vo+, the anode of described switching diode D1 and the negative pole of polar capacitor C1 connect and for BUCK converter cathode voltage output end vo-, cathode voltage output end vo-the ground connection of described BUCK converter, the cathode voltage output end vo+of described BUCK converter and cathode voltage output end vo-between be connected to load RL.
The utility model compared with prior art has the following advantages:
1, the utility model adopts voltage-type short-circuit protection circuit, and without the need to current detecting, circuit structure is simple, and power consumption is extremely low, reasonable in design, and it is convenient, with low cost to realize.
2, the utility model adopts formula output short circuit protection of having the hiccups, and circuit working, in the state of having the hiccups, judges whether output short-circuit by detectable voltage signals, once output short-circuit be detected, short-circuit protection circuit is action immediately, thoroughly cuts off the BUCK converter of input; After short-circuit signal disappears, BUCK converter recovers normal work; This circuit can reduce output average current when continuing overcurrent, and reduce circuit power consumption, and have automatic recovery ability completely, the thorough shutoff of property performance period, is highly suitable in intrinsically safe circuit.
3, the utility model utilizes diode unilateral conduction and capacitance voltage not to suddenly change and RC circuit discharging characteristic; realize having the hiccups the generation of formula output short circuit protection signal; with electric resistance partial pressure form, output voltage is sampled; using the benchmark of the voltage obtained by diode pair capacitor charging as formula output short circuit protection of having the hiccups; formula output short circuit protection of having the hiccups can be realized without the need to additional benchmark; make circuit structure more simple, save cost simultaneously.
4, the utility model utilizes the characteristic that electric capacity both end voltage can not be suddenlyd change, and by arranging suitable RC circuit parameter, determining the time needed for guard signal maintenance, realizing formula protection of having the hiccups, simple operation.
5, the utility model can when there is overload or short trouble in circuit; the energy source of thorough cut-out input; spark energy short circuit caused is limited in extremely low scope; can be used in various switch converters and related electronic products; especially in the hazardous environment such as colliery, petrochemical industry, can the incidence of effectively minimizing accident, protection property, personal safety; practical, be convenient to promote the use of.
In sum, the utility model circuit structure is simple, and with low cost, simple operation, can realize formula short-circuit protection of having the hiccups, have self-recovering function, practical, is convenient to promote the use of.
Below by drawings and Examples, the technical solution of the utility model is described in further detail.
Accompanying drawing explanation
Fig. 1 is circuit theory diagrams of the present utility model.
Description of reference numerals:
1-output short circuit protection circuit; 2-BUCK converter;
3-PWM controlling and driving circuits.
Embodiment
As shown in Figure 1, the utility model comprises comparator U1, switching diode D2 and nonpolar electric capacity C2, and resistance R1, resistance R2, resistance R3, resistance R4 and resistance R5, the anode of described switching diode D2 and one end of resistance R1 connect and are the input V-IN of described output short circuit protection circuit 1, the input V-IN of described output short circuit protection circuit 1 connects with the cathode voltage output of BUCK converter, the negative electrode of described switching diode D2 connects with one end of nonpolar electric capacity C2 and one end of resistance R3, the other end of described resistance R1 is by resistance R2 ground connection, the other end ground connection of described nonpolar electric capacity C2, the other end of described resistance R3 connects with the inverting input of comparator U1, and by resistance R4 ground connection, the link of described resistance R1 and resistance R2 and one end of resistance R5 all connect with the in-phase input end of comparator U1, the power end of described comparator U1 and the other end of resistance R5 all connect with the output VCC of power supply, the earth terminal ground connection of described comparator U1, the output of described comparator U1 is the output V-OUT of described output short circuit protection circuit 1, the output V-OUT of described output short circuit protection circuit 1 connects with the input of PWM controlling and driving circuits 3.
In the present embodiment, described comparator U1 is made up of chip LM393, and the output of described comparator U1 is connected with the output VCC of power supply by resistance R6.Resistance R6 is the pull-up resistor of the output of comparator U1, and when specifically implementing, the value of described resistance R6 is 10k Ω.
As shown in Figure 1, in the present embodiment, described BUCK converter 2 comprises PMOS switch pipe VT1, inductance L 1, switching diode D1 and polar capacitor C1, the grid of described PMOS switch pipe VT1 connects with the output of PWM controlling and driving circuits 3, the drain electrode of described PMOS switch pipe VT1 is the voltage input end Vi of BUCK converter 2, the source electrode of described PMOS switch pipe connects with one end of the negative electrode of switching diode D1 and inductance L 1, the other end of described inductance L 1 connect with the positive pole of polar capacitor C1 and for BUCK converter 2 cathode voltage output end vo+, the anode of described switching diode D1 and the negative pole of polar capacitor C1 connect and for BUCK converter 2 cathode voltage output end vo-, cathode voltage output end vo-the ground connection of described BUCK converter 2, the cathode voltage output end vo+of described BUCK converter 2 and cathode voltage output end vo-between be connected to load RL.Described PWM controlling and driving circuits 3 controls conducting and the shutoff of PMOS switch pipe VT1.
Operation principle of the present utility model is: circuit powered on moment, the output voltage V of BUCK converter 2
obe zero, the magnitude of voltage V of the inverting input of comparator U1
-1be zero, the input in the same way of comparator U1 is connected with the output VCC of power supply by resistance R5, now, and the magnitude of voltage of the input in the same way of comparator U1
due to V
+ 1>V
-1therefore the output of comparator U1 exports high level; namely the output V-OUT of described output short circuit protection circuit 1 exports high level; when the input of PWM controlling and driving circuits 3 detects that the output V-OUT of described output short circuit protection circuit 1 exports high level, produce pulse signal and drive BUCK converter 2 normally to work.
After circuit working is stable, according to superposition theorem, the magnitude of voltage of the in-phase input end of comparator U1
The magnitude of voltage of the inverting input of comparator U1
(because the electric current flowing through switching diode D2 is very little, the forward conduction voltage drop of switching diode D2 is very low, usual specific output voltage V
omuch smaller, therefore exist
computing formula in do not consider the forward conduction voltage drop of switching diode D2), due to the appropriate design of resistance R1, resistance R2, resistance R3, resistance R4 and resistance R5 parameter, can V be made
+ 2>V
-2therefore the output of comparator U1 exports high level; namely the output V-OUT of described output short circuit protection circuit 1 exports high level; when the input of PWM controlling and driving circuits 3 detects that the output V-OUT of described output short circuit protection circuit 1 exports high level, produce pulse signal and drive BUCK converter 2 normally to work.
When there is short trouble in circuit, the output voltage V of BUCK converter 2
orapid decline, the magnitude of voltage of the in-phase input end of comparator U1 also declines fast, and due to the unilateral conduction of diode D2, nonpolar electric capacity C2 can only be discharged by the loop formed by resistance R3, resistance R4 and nonpolar electric capacity C2, thus the anti-phase input terminal voltage of comparator U1 can only slowly be declined.Comparator U1 in-phase input end voltage ratio inverting input voltage drop is faster; now; comparator U1 in-phase input end voltage is lower than anti-phase input terminal voltage; therefore the output output low level of comparator U1; the i.e. output V-OUT output low level of described output short circuit protection circuit 1; when the input of PWM controlling and driving circuits 3 detects the output V-OUT output low level of described output short circuit protection circuit 1; turn off pulse signal; BUCK converter 2 quits work; until output voltage drops to zero, the magnitude of voltage of the in-phase input end of comparator U1 becomes
the magnitude of voltage of the inverting input of comparator U1 simultaneously
along with U
c2 (t)decline and reduce, as long as but meet formula V
+ 3<V
-3time, the output output low level always of comparator U1, the i.e. output V-OUT output low level of described output short circuit protection circuit 1, when the input of PWM controlling and driving circuits 3 detects the output V-OUT output low level of described output short circuit protection circuit 1, turn off pulse signal, BUCK converter 2 still quits work; Along with continuing of nonpolar electric capacity C2 discharge process, the voltage at nonpolar electric capacity C2 two ends constantly reduces, when meeting formula V
+ 3>V
-3time; the output of comparator U1 exports high level; namely the output V-OUT of described output short circuit protection circuit 1 exports high level; when the input of PWM controlling and driving circuits 3 detects that the output V-OUT of described output short circuit protection circuit 1 exports high level; producing pulse signal drives BUCK converter 2 to restart, and recovers normally to work.
The above; it is only preferred embodiment of the present utility model; not the utility model is imposed any restrictions; every above embodiment is done according to the utility model technical spirit any simple modification, change and equivalent structure change, all still belong in the protection range of technical solutions of the utility model.
Claims (3)
1. an output short circuit protection circuit for BUCK converter, is characterized in that: comprise comparator U1, switching diode D2 and nonpolar electric capacity C2, and resistance R1, resistance R2, resistance R3, resistance R4 and resistance R5, the anode of described switching diode D2 and one end of resistance R1 connect and are the input V-IN of described output short circuit protection circuit (1), the input V-IN of described output short circuit protection circuit (1) connects with the cathode voltage output of BUCK converter, the negative electrode of described switching diode D2 connects with one end of nonpolar electric capacity C2 and one end of resistance R3, the other end of described resistance R1 is by resistance R2 ground connection, the other end ground connection of described nonpolar electric capacity C2, the other end of described resistance R3 connects with the inverting input of comparator U1, and by resistance R4 ground connection, the link of described resistance R1 and resistance R2 and one end of resistance R5 all connect with the in-phase input end of comparator U1, the power end of described comparator U1 and the other end of resistance R5 all connect with the output VCC of power supply, the earth terminal ground connection of described comparator U1, the output of described comparator U1 is the output V-OUT of described output short circuit protection circuit (1), the output V-OUT of described output short circuit protection circuit (1) connects with the input of PWM controlling and driving circuits (3).
2. according to the output short circuit protection circuit of a kind of BUCK converter according to claim 1, it is characterized in that: described comparator U1 is made up of chip LM393, the output of described comparator U1 is connected with the output VCC of power supply by resistance R6.
3. according to the output short circuit protection circuit of a kind of BUCK converter according to claim 1, it is characterized in that: described BUCK converter (2) comprises PMOS switch pipe VT1, inductance L 1, switching diode D1 and polar capacitor C1, the grid of described PMOS switch pipe VT1 connects with the output of PWM controlling and driving circuits (3), the drain electrode of described PMOS switch pipe VT1 is the voltage input end Vi of BUCK converter (2), the source electrode of described PMOS switch pipe connects with one end of the negative electrode of switching diode D1 and inductance L 1, the other end of described inductance L 1 connect with the positive pole of polar capacitor C1 and for BUCK converter (2) cathode voltage output end vo+, the anode of described switching diode D1 and the negative pole of polar capacitor C1 connect and for BUCK converter (2) cathode voltage output end vo-, cathode voltage output end vo-the ground connection of described BUCK converter (2), the cathode voltage output end vo+of described BUCK converter (2) and cathode voltage output end vo-between be connected to load RL.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520278071.8U CN204517374U (en) | 2015-04-30 | 2015-04-30 | A kind of output short circuit protection circuit of BUCK converter |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520278071.8U CN204517374U (en) | 2015-04-30 | 2015-04-30 | A kind of output short circuit protection circuit of BUCK converter |
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| Publication Number | Publication Date |
|---|---|
| CN204517374U true CN204517374U (en) | 2015-07-29 |
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|---|---|---|---|
| CN201520278071.8U Expired - Fee Related CN204517374U (en) | 2015-04-30 | 2015-04-30 | A kind of output short circuit protection circuit of BUCK converter |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| TWI575351B (en) * | 2016-03-08 | 2017-03-21 | 瑞昱半導體股份有限公司 | Regulator |
| CN108270210A (en) * | 2016-12-30 | 2018-07-10 | 新唐科技股份有限公司 | Power supply switch device |
| CN109921378A (en) * | 2019-04-03 | 2019-06-21 | 航天柏克(广东)科技有限公司 | A kind of DC switch circuit and its control method |
-
2015
- 2015-04-30 CN CN201520278071.8U patent/CN204517374U/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| TWI575351B (en) * | 2016-03-08 | 2017-03-21 | 瑞昱半導體股份有限公司 | Regulator |
| CN108270210A (en) * | 2016-12-30 | 2018-07-10 | 新唐科技股份有限公司 | Power supply switch device |
| CN109921378A (en) * | 2019-04-03 | 2019-06-21 | 航天柏克(广东)科技有限公司 | A kind of DC switch circuit and its control method |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20150729 Termination date: 20170430 |