CN211508592U - Output short circuit detection protection circuit - Google Patents
Output short circuit detection protection circuit Download PDFInfo
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- CN211508592U CN211508592U CN201922338018.3U CN201922338018U CN211508592U CN 211508592 U CN211508592 U CN 211508592U CN 201922338018 U CN201922338018 U CN 201922338018U CN 211508592 U CN211508592 U CN 211508592U
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Abstract
The embodiment of the utility model discloses output short circuit detection protection circuit belongs to electronic circuit field technical field. The circuit comprises n first diodes Dn, a comparator U and n sampling resistors Rn, wherein the anode of each first diode Dn is connected with the grid electrode of an output driver Qn, and the cathode of each first diode Dn is connected with the output end of the comparator U; the in-phase output end of the comparator U is connected with a reference voltage, and the reverse-phase output end of the comparator U is connected with the source electrode of the output driver Qn; one end of the sampling resistor Rn is grounded, and the other end of the sampling resistor Rn is connected with the source electrode of the output circuit Qn; wherein n is an integer greater than or equal to 1. Adopt the embodiment of the utility model provides a, detect sensitively, the protection is rapid, and the protection of multiplexed output can be realized to single protection circuit, can set for each way output protection circuit threshold value in a flexible way respectively.
Description
Technical Field
The embodiment of the utility model provides an electronic circuit technical field especially relates to an output short circuit detection protection circuit.
Background
Output control or drive signals are used in all fields involving electronics, such as in the automotive industry and industrial control. Protection of the output circuit against short-circuits is a fundamental requirement for circuit protection.
The conventional method in the prior art is to connect a fast recovery fuse device in series on a main power supply, such as a Q1 driving circuit in fig. 1, and connect a fast recovery fuse device F in series on the power supply, where the fuse device acts to limit the short-circuit current when the output is short-circuited, so as to protect the output circuit. However, with this kind of safety method, only one output circuit can be protected, and for a driving circuit with multiple output circuits, a fast recovery protection device needs to be connected in series in each output circuit to be protected; moreover, this circuit can only protect the driving circuit of which power is output by the board, i.e. the power supply of the load is connected with the output interface of the controller, and for some circuits of which the output of the controller is just switched and does not supply power or power to the load, such as the Q2 driving circuit in fig. 2, this method of connecting a fuse in series on the power supply of the controller is not applicable.
SUMMERY OF THE UTILITY MODEL
In view of this, an object of the embodiments of the present invention is to provide an output short circuit detection protection circuit to solve the problem that the prior art cannot protect the circuit that does not provide power for the load in the manner of serially connecting the fast recovery fuse on the power supply, and cannot protect a plurality of output circuits at the same time.
The embodiment of the utility model provides a solve the technical scheme that above-mentioned technical problem adopted as follows:
an output short circuit detection protection circuit is provided, the circuit includes n first diodes Dn, a comparator U, and n sampling resistors Rn:
the anode of the first diode Dn is connected with the grid of the output driver Qn, and the cathode of the first diode Dn is connected with the output end of the comparator U;
the in-phase output end of the comparator U is connected with a reference voltage, and the reverse-phase output end of the comparator U is connected with the source electrode of the output driver Qn;
one end of the sampling resistor Rn is grounded, and the other end of the sampling resistor Rn is connected with the source electrode of the output driver Qn;
wherein n is an integer greater than or equal to 1.
Furthermore, the circuit is further provided with a holding capacitor C and n second diodes Dn':
the second diode Dn' is connected in series between the reverse output end of the comparator U and the source electrode of the output driver Qn, the anode of the second diode Dn is connected with the source electrode of the output driver Qn, and the cathode of the second diode Dn is connected with the reverse input end of the comparator U;
and one end of the holding capacitor C is connected with the inverting input end of the comparator U, and the other end of the holding capacitor C is grounded.
Further, the circuit also comprises a discharge resistor RfSaid discharge resistance RfIs connected with the inverting input terminal of the comparator U, and the other end is grounded.
Further, the circuit also comprises a resistor RaAnd a resistance Rb：
The resistor RaOne end of the comparator is connected with the in-phase output end of the comparator, and the other end of the comparator inputs the reference voltage;
the resistor RbOne end of the comparator is connected with the in-phase output end of the comparator, and the other end of the comparator is grounded.
Further, the output driver Qn is a field effect transistor.
Further, the reference voltage is 5V.
The utility model discloses output short circuit detection protection circuit has following advantage:
1. a first diode is connected to the gate circuit of each output driver, and a sampling resistor is connected to the source of each output driver, so that the plurality of first diodes D1, D2, D3 and the resistor RfA simple OR logic circuit is formed, short circuit detection and protection can be realized when any one output circuit is short-circuited, multi-path output protection is realized, and the threshold values of all paths of output protection circuits can be flexibly set respectively;
2. because the output short circuit detection protection circuit is directly connected with the output driver in series, a protected object is not limited to a circuit for providing power supply or power for a load any more;
3. the detection is sensitive and the protection is rapid;
4. in the sampling circuit, increaseWith the holding circuit, the action time of the protection circuit can be prolonged, the on duty ratio of the short-circuit current can be reduced, the average current can be reduced, the output driver Q1 and the load device can be effectively protected, and the discharge resistor R is arrangedfThe voltage of the holding capacitor C can be released slowly, the holding time is set, secondary protection is realized, and the large current can be effectively prevented from impacting the output driver Q3.
Drawings
FIG. 1 is a circuit diagram illustrating a prior art series connection of a fast recovery fuse device to a main power supply;
FIG. 2 is a prior art circuit diagram in which the output is switched only and no power is supplied to the load;
fig. 3 is a schematic circuit diagram of an output short circuit detection protection circuit according to a first embodiment of the present invention;
fig. 4 is a schematic circuit diagram of a possible implementation of an output short-circuit detection protection circuit according to an embodiment of the present invention;
fig. 5 is a circuit diagram of an output short detection protection circuit according to an embodiment of the present invention when protecting a single-output driving circuit;
fig. 6 is a circuit diagram of the output short circuit detection protection circuit according to an embodiment of the present invention protecting the multiple output driving circuit.
The implementation, functional characteristics and advantages of the embodiments of the present invention will be further described with reference to the accompanying drawings.
Detailed Description
In order to make the technical problems, technical solutions and advantageous effects to be solved by the embodiments of the present invention clearer and more obvious, the embodiments of the present invention are further described in detail below with reference to the accompanying drawings and the embodiments. It should be understood that the description herein of specific embodiments is intended to be illustrative of the embodiments of the invention and is not intended to limit the embodiments of the invention.
The embodiment of the present invention provides an output short circuit detection protection circuit, please refer to fig. 3, the circuit includes n first diodes Dn, comparator and n sampling resistors Rn:
the anode of the first diode Dn is connected with the grid of the output driver Qn, and the cathode of the first diode Dn is connected with the output end of the comparator U;
the in-phase output end of the comparator U is connected with a reference voltage, and the reverse-phase output end of the comparator U is connected with the source electrode of the output driver Qn;
one end of the sampling resistor Rn is grounded, and the other end of the sampling resistor Rn is connected with the source electrode of the output driver Qn;
wherein n is an integer greater than or equal to 1.
In one possible embodiment, referring to fig. 4, the circuit further includes a holding capacitor C, n, a second diode Dn' and a discharge resistor Rf：
The second diode Dn 'is connected in series between the reverse output end of the comparator U and the source electrode of the output driver Qn, the anode of the second diode Dn' is connected with the source electrode of the output driver Qn, and the cathode is connected with the reverse input end of the comparator U;
the discharge resistor RfOne end of the comparator U is connected with the inverting input end of the comparator U, and the other end of the comparator U is grounded;
one end of the holding capacitor C is connected with the inverting input end of the comparator U, and the other end of the holding capacitor C is grounded.
In one possible embodiment, the circuit further comprises a resistor RaAnd a resistance Rb：
The resistor RaOne end of the comparator is connected with the in-phase output end of the comparator, and the other end of the comparator inputs the reference voltage;
the resistor RbOne end of the comparator is connected with the in-phase output end of the comparator, and the other end of the comparator is grounded.
In one possible implementation, the output driver Qn is a field effect transistor.
In one possible approach, the reference voltage is 5V.
In practical applications, the parameters of the n sampling resistors and the first diode Dn are determined according to the output driver Qn to be protected.
The present embodiment will be described in detail below with reference to specific circuits.
If the driving circuit is a single-output driving circuit, n is 1, and the configuration of the output short-circuit detection protection circuit is shown in fig. 4.
The output loop of the driving circuit is connected with a sampling resistor R1 in series, and the voltage signal at the upper end of R1 represents the current value. The in-phase output end of the comparator U is provided with reference voltage, and a short-circuit current protection threshold value is set.
When the driving circuit works normally, the sampling voltage at the upper end of the sampling resistor R1 is lower than a set protection threshold value, the comparator U outputs high level, the first diode D1 is cut off in reverse phase, the output short circuit detection protection circuit does not act, and the driving circuit is not influenced.
When the driving circuit is short-circuited, the sampling voltage at the upper end of the R1 is increased and exceeds the set protection threshold, the comparator is inverted and outputs low level, the first diode D1 is turned on, the grid driving voltage of the output driver Q1 is pulled down, and the output driver Q1 is turned off quickly.
The output short circuit detection protection circuit shown in fig. 5 is added with a holding circuit in a sampling circuit, and mainly comprises a second diode D1', a holding capacitor C and a discharge resistor RfAnd (4) forming. The addition of the holding circuit has three main functions:
1. the sampling voltage is kept by a second diode D1' and a holding capacitor C of the holding circuit, so that the action time of the protection circuit is prolonged, the conduction duty ratio of short-circuit current is reduced, the average current is reduced, and the output driver Q1 and load equipment are effectively protected;
2. setting a discharge resistance RfThe voltage of the capacitor C can be released slowly, the holding time is set, when the voltage of the capacitor C is released to be slightly lower than the reference voltage, the comparator U is turned over, the output driver Q1 tries to recover the output, and if the short circuit is removed, the output driver Q1 can recover normally; if the short circuit is not released, the protection is repeatedly carried out again;
3. during secondary protection, the voltage of the holding capacitor C is still kept near the reference voltage, so that the secondary protection reacts quickly, and large current can be effectively prevented from impacting the output driver Q3.
If the driving circuit is a three-way output driving circuit, n is 3, and the structure of the output short-circuit detection protection circuit is shown in fig. 6.
At this time, the output short detection protection circuit is provided with three first diodes (D1, D2, D3), three second diodes (D1 ', D2 ', D3 '), and three sampling resistors (R1, R2, R3), in which:
a first diode D1, a comparator U, and a discharge resistor RfThe second diode D1' and the sampling resistor R1 form an output detection protection circuit of the output driver Q1;
a first diode D2, a comparator U, and a discharge resistor RfThe second diode D2' and the sampling resistor R2 form an output detection protection circuit of the output driver Q2;
a first diode D3, a comparator U, and a discharge resistor RfThe second diode D3' and the sampling resistor R3 constitute an output detection protection circuit of the output driver Q3.
Functionally, the first diodes D1, D2, D3 and the resistor RfThe simple OR logic circuit is formed, so that short circuit detection can be realized by ensuring that any one output circuit is short-circuited.
Specifically, the comparator outputs are connected to the gate circuits of the output drivers Q1, Q2, Q3 through three first diodes D1, D2, D3, respectively. As long as the output of the comparator is inverted to a low level, the gate level can be forced to be pulled down at the same time, and the driving output is turned off. These first diodes serve, on the one hand, to isolate the output level of the comparator U and, on the other hand, to set the protection current of the output of each driver circuit individually.
The output short circuit detection protection circuit of the embodiment has the following advantages:
1. a first diode is connected to a gate circuit of each output driver, a sampling resistor is connected to a source electrode of each output driver, so that a plurality of first diodes D1, D2, D3 and a resistor Rf form a simple OR logic circuit, short-circuit detection and protection can be realized when any one output circuit is short-circuited, multi-path output protection is realized, and the threshold value of each output protection circuit can be flexibly set;
2. because the output short circuit detection protection circuit is directly connected with the output driver in series, a protected object is not limited to a circuit for providing power supply or power for a load any more;
3. the detection is sensitive and the protection is rapid;
4. in the sampling circuit, a holding circuit is added, so that the action time of a protection circuit can be prolonged, the conduction duty ratio of short-circuit current is reduced, the average current is reduced, the output driver Q1 and load equipment are effectively protected, and a discharge resistor R is arrangedfThe voltage of the holding capacitor C can be released slowly, the holding time is set, secondary protection is realized, and the large current can be effectively prevented from impacting the output driver Q3.
The preferred embodiments of the present invention have been described above with reference to the accompanying drawings, and are not intended to limit the scope of the embodiments of the invention. Any modifications, equivalents and improvements which may occur to those skilled in the art without departing from the scope and spirit of the embodiments of the present invention are intended to be within the scope of the claims of the embodiments of the present invention.
Claims (6)
1. An output short circuit detection protection circuit, comprising n first diodes Dn, a comparator U, and n sampling resistors Rn:
the anode of the first diode Dn is connected with the grid of the output driver Qn, and the cathode of the first diode Dn is connected with the output end of the comparator U;
the in-phase output end of the comparator U is connected with a reference voltage, and the reverse-phase output end of the comparator U is connected with the source electrode of the output driver Qn;
one end of the sampling resistor Rn is grounded, and the other end of the sampling resistor Rn is connected with the source electrode of the output driver Qn;
wherein n is an integer greater than or equal to 1.
2. The output short-circuit detection protection circuit of claim 1, further comprising a holding capacitor C and n second diodes Dn':
the second diode Dn' is connected in series between the reverse output end of the comparator U and the source electrode of the output driver Qn, the anode of the second diode Dn is connected with the source electrode of the output driver Qn, and the cathode of the second diode Dn is connected with the reverse input end of the comparator U;
and one end of the holding capacitor C is connected with the inverting input end of the comparator U, and the other end of the holding capacitor C is grounded.
3. The output short detection protection circuit of claim 2, further comprising a discharge resistor RfSaid discharge resistance RfIs connected with the inverting input terminal of the comparator U, and the other end is grounded.
4. The output short detection protection circuit of claim 2, further comprising a resistor RaAnd a resistance Rb：
The resistor RaOne end of the comparator is connected with the in-phase output end of the comparator, and the other end of the comparator inputs the reference voltage;
the resistor RbOne end of the comparator is connected with the in-phase output end of the comparator, and the other end of the comparator is grounded.
5. The output short detection protection circuit of claim 1, wherein the output driver Qn is a field effect transistor.
6. The output short detection protection circuit of claim 1, wherein the reference voltage is 5V.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201922338018.3U CN211508592U (en) | 2019-12-23 | 2019-12-23 | Output short circuit detection protection circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201922338018.3U CN211508592U (en) | 2019-12-23 | 2019-12-23 | Output short circuit detection protection circuit |
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| CN211508592U true CN211508592U (en) | 2020-09-15 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115032567A (en) * | 2022-08-15 | 2022-09-09 | 南通江海电容器股份有限公司 | Electrolytic capacitor short circuit detection system |
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2019
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115032567A (en) * | 2022-08-15 | 2022-09-09 | 南通江海电容器股份有限公司 | Electrolytic capacitor short circuit detection system |
| CN115032567B (en) * | 2022-08-15 | 2022-11-04 | 南通江海电容器股份有限公司 | Electrolytic capacitor short circuit detection system |
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Effective date of registration: 20210225 Address after: 518000 area B and C, 2 / F, Mindray R & D building, 009 Keji South 12th Road, Gaoxin community, Yuehai street, Nanshan District, Shenzhen City, Guangdong Province Patentee after: Shenzhen Moji Zhixing Technology Co.,Ltd. Address before: 518000 Guangdong, Shenzhen, Nanshan District, Guangdong Province, Nanshan District high tech Industrial Park, South Korea 12 road, MINDRAY Building 2 floor B area, zone 12 Patentee before: Gaoxing Wulian Technology Co.,Ltd. |