CN202797867U - Short circuit protection circuit and power supply circuit provided with the same - Google Patents
Short circuit protection circuit and power supply circuit provided with the same Download PDFInfo
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- CN202797867U CN202797867U CN 201220393437 CN201220393437U CN202797867U CN 202797867 U CN202797867 U CN 202797867U CN 201220393437 CN201220393437 CN 201220393437 CN 201220393437 U CN201220393437 U CN 201220393437U CN 202797867 U CN202797867 U CN 202797867U
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- circuit protection
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Abstract
The utility model discloses a short circuit protection circuit and a power supply circuit provided with the same. The short circuit protection circuit comprises a comparator and a control element. The comparator can be used to compare a voltage across a sampling resistor serially connected with a load and a reference voltage, and can be used to output a short circuit protection signal, when the short circuit of the load occurs, in addition, an input end is connected with the sampling resistor and the load. The control element can be used to cut off a transmission channel between an input power supply and the load, when the short circuit protection signal is received. An enabling end of the control element is connected with the output end of the comparator, and a control end is connected with the transmission channel between the input power supply and the load. By using the short circuit protection circuit provided in the utility model, the damage on elements of the circuit caused by the short circuit current can be effectively prevented, when the short circuit of the load occurs. The short circuit protection circuit has advantages of simple structure, low realization costs, and wide applicability in various power supply circuits having topological structures.
Description
Technical field
The utility model relates to a kind of protective circuit, especially relates to a kind of short-circuit protection circuit, and the power circuit with short-circuit protection circuit.
Background technology
When low-voltage dc circuit was short-circuited, excessive short circuit current can cause electronic component damage in the circuit.At present, there is multiple specific implementation approach in the short-circuit protection circuit of low-voltage dc circuit, and for the different application occasion, the short-circuit protection circuit that adopts is not quite similar.Short-circuit protection circuit generally detects principle based on two kinds: a kind of is large electric current when detecting short circuit; Another kind is the voltage when detecting short circuit.
One type short-circuit protection circuit comprises the power current fuse between power supply and relay drive circuit.When being short-circuited, the fuse fusing also disconnects.In addition, the short-circuit protection circuit monitoring flow is to electric current and the Limited Current amount of relay drive circuit, avoids the infringement that causes owing to short circuit with the protection relay drive circuit.This short-circuit protection circuit needs the frequent fuse, and the circuit maintenance cost is higher, and troublesome poeration.
One type short-circuit protection circuit is forced the output function of slew relay drive circuit when short circuit occurs, and prevents that short circuit current from flowing to relay drive circuit.After the scheduled time of when being short-circuited, rising, short circuit with predetermined time the interval send restoring signal to relay drive circuit, with the output function of reset relay drive circuit.The complex structure of this kind short-circuit protection circuit, circuit realize that cost is higher.
The utility model content
The defective that exists for overcoming prior art, the utility model proposes a kind of simple in structure, realize lower-cost short-circuit protection circuit, and the power circuit with short-circuit protection circuit damages to avoid short circuit current that power circuit is produced.
The utility model adopts following technical scheme to realize: a kind of short-circuit protection circuit, and it comprises:
Voltage and reference voltage for the sampling resistor two ends that will be connected in series load compare, the comparator of output short circuit protection signal when load generation short circuit current, and its input connects described sampling resistor and described load;
Be used for when receiving described short-circuit protection signal; control is cut off input power to the control element of the transmission channel of described load, and the Enable Pin of described control element connects described comparator output terminal, control end is connected to described input power to the transmission channel of described load.
Wherein, described control element is transistor Q3, described Enable Pin is that the base stage of described transistor Q3, described control end are the collector electrode of described transistor Q3, and base stage is serially connected in the grid of the transistor Q1 among the described transmission channel by output, grounded emitter, the collector electrode connection that drives resistance R 4 connection comparators.
Wherein, the input of described comparator connects the negative electrode of diode D3, and the anode of described diode D3 connects respectively described sampling resistor and described load.
Accordingly; the utility model discloses a kind of power circuit with short-circuit protection circuit; it comprises input power, be connected to voltage up converting circuit between described input power and the load, be connected in series the sampling resistor of described load; be connected to the short-circuit protection circuit between described sampling resistor and the described voltage up converting circuit, this short-circuit protection circuit comprises:
Voltage and reference voltage for the sampling resistor two ends that will be connected in series load compare, the comparator of output short circuit protection signal when load generation short circuit current, and its input connects described sampling resistor and described load;
Be used for when receiving described short-circuit protection signal; control is cut off input power to the control element of the transmission channel of described load, and the Enable Pin of described control element connects described comparator output terminal, control end is connected to described input power to the transmission channel of described load.
Wherein, described sampling resistor comprises resistance R 2 and the resistance R 3 of 2 parallel connections.
Wherein, described voltage up converting circuit comprises:
The energy-storage travelling wave tube that connects described input power, described energy-storage travelling wave tube connects described load by diode D2;
It is drain electrode that one end of described energy-storage travelling wave tube connects transistor Q2, and the other end connects the negative electrode of diode D1, and wherein the source ground of transistor D2, grid drive resistance R 5 connections for the control controller U2 in transistor Q2 conducting when receiving described short-circuit protection signal by one;
Hold current circuit in the parallel connection of the two ends of diode D1 by what two divider resistance R1, R6 and transistor Q1 consisted of, the grid of described transistor Q1 connects the collector electrode of described transistor Q3, and the source ground of described transistor Q1, drain electrode are connected between described input power and the described energy-storage travelling wave tube.
Wherein, described energy-storage travelling wave tube is inductance L 1.
Wherein, one of them input of described controller U2 connects the output of described comparator.
Compared with prior art, the utlity model has following beneficial effect:
The short-circuit protection circuit that the utility model proposes, in the time of can effectively avoiding load to be short-circuited, short circuit current produces components and parts in the circuit and damages.And, this short-circuit protection circuit simple in structure, realize that cost is lower, can be widely used in the power circuit of various topological structures.
Description of drawings
Fig. 1 is the theory diagram of the utility model power circuit;
Fig. 2 is the structural representation of the utility model power circuit;
Fig. 3 is the equivalent circuit structure schematic diagram when load is short-circuited among Fig. 2.
Embodiment
As shown in Figure 1, the power circuit that the utility model proposes comprises: the DC power supply of input is carried out the rectification circuit that rectification is processed; Be connected to the voltage up converting circuit of rectification circuit output end, after processing for the DC power supply of input is boosted, powering load; Connect load, be used for the short circuit sample circuit that the electric current of the load of flowing through is sampled; Be connected to the short-circuit protection circuit between short circuit sample circuit and the voltage up converting circuit, be used for when load is short-circuited, carrying out short-circuit protection.
In conjunction with shown in Figure 2, at a preferred embodiment, rectification circuit is comprised of 4 rectifier diode D4, D5, D6 and D7.
Voltage up converting circuit comprises: the inductance L 1 that connects rectification circuit output end; One end of inductance L 1 connects the drain electrode of transistor Q2, and the other end of inductance L 1 connects the negative electrode of diode D1, the source ground of transistor Q2 wherein, and grid drives resistance R 5 by one and connects controller U2; Hold current circuit in the parallel connection of the two ends of diode D1 by what divider resistance R1, R6 and transistor Q1 consisted of, form bleeder circuit by divider resistance R1, R6 and come driving transistors Q1 work, between diode D1 and ground, form to hold and flow back to the road; The sub-VIN+ of direct-flow input end, the direct-current input power supplying of VIN-input through behind the rectification circuit, is inputted out inductance L 1, and through diode D2 powering load, and the conducting by controller U2 control transistor Q2 with turn-off to inductance L 1 storage power to improve the output voltage of powering load.
The short circuit sample circuit comprises in parallel sampling resistor R2 and R3, and two sampling resistor R2 are connected one of them common port and connect load with R3, and other end ground connection.
Short-circuit protection circuit comprises: the diode D3 of two sampling resistor R2 of anodic bonding and R3; the negative electrode of this diode D3 connects the input of comparator U1; and the output of comparator U1 connects the base stage of transistor Q3 by driving resistance R 4; and the grounded emitter of transistor Q3, collector electrode connects the grid of vigilant pipe Q1.
During normal operation, by divider resistance R1, R6 the DC power supply of input is carried out dividing potential drop, the grid of transistor Q1 is high level, always conducting of transistor Q1, make between rectification circuit, voltage up converting circuit and the load and form the closed-loop path, inductance L 1 discharge is by diode D2 powering load.
In conjunction with shown in Figure 3; when load produces short circuit; the electric current of load can raise moment; at this moment; the both end voltage moment rising of sampling resistor R2, R3; amplifier and reference voltage by comparator U1 inside compare; comparator U1 exports high level; make transistor Q3 conducting by driving resistance R 4; and then the grid of pulldown transistors Q1 makes its current potential vanishing current potential; moment disconnection transistor Q1 makes and no longer forms the closed-loop path between rectification circuit, voltage up converting circuit and the load, thereby plays the function of protection.Simultaneously; after controller U2 detects short-circuit protection signal (the output output high level of comparator U2); send a constant high level and make its always conducting to the grid of transistor Q2; like this; energy in the inductance L 1 forms discharge loop by vigilant Q2, diode D1, has avoided the instantaneous short circuit protection to cause inductance L 1 not have discharge loop generation electric arc to cause damage to power circuit.
The above only is preferred embodiment of the present utility model; not in order to limit the utility model; all any modifications of within spirit of the present utility model and principle, doing, be equal to and replace and improvement etc., all should be included within the protection range of the present utility model.
Claims (10)
1. a short-circuit protection circuit is characterized in that, comprising:
Voltage and reference voltage for the sampling resistor two ends that will be connected in series load compare, the comparator of output short circuit protection signal when load generation short circuit current, and its input connects described sampling resistor and described load;
Be used for when receiving described short-circuit protection signal; control is cut off input power to the control element of the transmission channel of described load, and the Enable Pin of described control element connects described comparator output terminal, control end is connected to described input power to the transmission channel of described load.
2. described short-circuit protection circuit according to claim 1; it is characterized in that; described control element is transistor Q3; described Enable Pin is that the base stage of described transistor Q3, described control end are the collector electrode of described transistor Q3, and base stage is serially connected in the grid of the transistor Q1 among the described transmission channel by output, grounded emitter, the collector electrode connection that drives resistance R 4 connection comparators.
3. described short-circuit protection circuit according to claim 1 is characterized in that, the input of described comparator connects the negative electrode of diode D3, and the anode of described diode D3 connects respectively described sampling resistor and described load.
4. power circuit with short-circuit protection circuit; it comprises input power, be connected to voltage up converting circuit between described input power and the load, be connected in series the sampling resistor of described load; it is characterized in that; also comprise: be connected to the short-circuit protection circuit between described sampling resistor and the described voltage up converting circuit, described short-circuit protection circuit comprises:
Voltage and reference voltage for the sampling resistor two ends that will be connected in series load compare, the comparator of output short circuit protection signal when load generation short circuit current, and its input connects described sampling resistor and described load;
Be used for when receiving described short-circuit protection signal; control is cut off input power to the control element of the transmission channel of described load, and the Enable Pin of described control element connects described comparator output terminal, control end is connected to described input power to the transmission channel of described load.
5. described power circuit with short-circuit protection circuit according to claim 4; it is characterized in that; described control element is transistor Q3; described Enable Pin is that the base stage of described transistor Q3, described control end are the collector electrode of described transistor Q3, and base stage is serially connected in the grid of the transistor Q1 among the described transmission channel by output, grounded emitter, the collector electrode connection that drives resistance R 4 connection comparators.
6. described power circuit with short-circuit protection circuit according to claim 4 is characterized in that, the input of described comparator connects the negative electrode of diode D3, and the anode of described diode D3 connects respectively described sampling resistor and described load.
7. described power circuit with short-circuit protection circuit according to claim 4 is characterized in that described sampling resistor comprises resistance R 2 and the resistance R 3 of 2 parallel connections.
8. according to claim 4 or 5 or 6 or 7 described power circuits with short-circuit protection circuit, it is characterized in that described voltage up converting circuit comprises:
The energy-storage travelling wave tube that connects described input power, described energy-storage travelling wave tube connects described load by diode D2;
It is drain electrode that one end of described energy-storage travelling wave tube connects transistor Q2, and the other end connects the negative electrode of diode D1, and wherein the source ground of transistor D2, grid drive resistance R 5 connections for the control controller U2 in transistor Q2 conducting when receiving described short-circuit protection signal by one;
Hold current circuit in the parallel connection of the two ends of diode D1 by what two divider resistance R1, R6 and transistor Q1 consisted of, the grid of described transistor Q1 connects the collector electrode of described transistor Q3, and the source ground of described transistor Q1, drain electrode are connected between described input power and the described energy-storage travelling wave tube.
9. described power circuit with short-circuit protection circuit according to claim 8 is characterized in that described energy-storage travelling wave tube is inductance L 1.
10. described power circuit with short-circuit protection circuit according to claim 8 is characterized in that one of them input of described controller U2 connects the output of described comparator.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220393437 CN202797867U (en) | 2012-08-09 | 2012-08-09 | Short circuit protection circuit and power supply circuit provided with the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220393437 CN202797867U (en) | 2012-08-09 | 2012-08-09 | Short circuit protection circuit and power supply circuit provided with the same |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN202797867U true CN202797867U (en) | 2013-03-13 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 201220393437 Expired - Lifetime CN202797867U (en) | 2012-08-09 | 2012-08-09 | Short circuit protection circuit and power supply circuit provided with the same |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN202797867U (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103595035A (en) * | 2013-11-14 | 2014-02-19 | 江苏绿扬电子仪器集团有限公司 | Protective circuit capable of improving performance of power source |
| CN103746331A (en) * | 2014-01-27 | 2014-04-23 | 上海誉煊电子技术有限公司 | Multifunctional fireproof short-circuit protector with redundant device |
| CN106034369A (en) * | 2015-03-10 | 2016-10-19 | 赛尔富电子有限公司 | LED power supply with short-circuit protection circuit |
| CN107785968A (en) * | 2017-12-05 | 2018-03-09 | 广州金升阳科技有限公司 | The battery short circuit protection circuit of charge power supply |
-
2012
- 2012-08-09 CN CN 201220393437 patent/CN202797867U/en not_active Expired - Lifetime
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103595035A (en) * | 2013-11-14 | 2014-02-19 | 江苏绿扬电子仪器集团有限公司 | Protective circuit capable of improving performance of power source |
| CN103746331A (en) * | 2014-01-27 | 2014-04-23 | 上海誉煊电子技术有限公司 | Multifunctional fireproof short-circuit protector with redundant device |
| CN103746331B (en) * | 2014-01-27 | 2016-05-25 | 上海誉煊电子技术有限公司 | With the multifunctional fire-proof short-circuit protector of redundant apparatus |
| CN106034369A (en) * | 2015-03-10 | 2016-10-19 | 赛尔富电子有限公司 | LED power supply with short-circuit protection circuit |
| CN106034369B (en) * | 2015-03-10 | 2018-08-31 | 赛尔富电子有限公司 | A kind of LED power with short-circuit protection circuit |
| CN107785968A (en) * | 2017-12-05 | 2018-03-09 | 广州金升阳科技有限公司 | The battery short circuit protection circuit of charge power supply |
| CN107785968B (en) * | 2017-12-05 | 2024-02-13 | 广州金升阳科技有限公司 | Battery short-circuit protection circuit of charging power supply |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CX01 | Expiry of patent term | ||
| CX01 | Expiry of patent term |
Granted publication date: 20130313 |