CN205178467U - Load short circuit protection circuit and dc supply equipment - Google Patents
Load short circuit protection circuit and dc supply equipment Download PDFInfo
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- CN205178467U CN205178467U CN201520856875.1U CN201520856875U CN205178467U CN 205178467 U CN205178467 U CN 205178467U CN 201520856875 U CN201520856875 U CN 201520856875U CN 205178467 U CN205178467 U CN 205178467U
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Abstract
The utility model discloses a load short circuit protection circuit and dc supply equipment. Circuit connection is between load (22) of DC power supply (1) and dc supply equipment in load short circuit protection, load short circuit protection circuit includes: trigger circuit (211), latch circuit (212) and switch circuit (213), trigger circuit (211) are parallelly connected with load (22), and latch circuit (212) are parallelly connected with DC power supply (1), and establish ties on the current path of load (22) switch circuit (213), and the output and latch circuit's (212) the input of trigger circuit (211) are connected, and the output and switch circuit's (213) the input of latch circuit (212) are connected. Load short circuit that this embodiment provided protection circuit, the circuit is simply with low costs, has realized when the short circuit condition appears in the load, and locking shortcircuit condition, proof load are in switching -off state always, have protected the load effectively, also can avoid the damage that DC power supply caused because of the permanent output heavy current simultaneously.
Description
Technical field
The utility model relates to field of circuit control, particularly relates to a kind of load short circuits protection circuit and DC suppling equipment.
Background technology
Electronic equipment occurs that in long-term work process short-circuit conditions can hardly be avoided, often along with very large short circuit current during short circuit, higher heat and temperature may be produced at short notice, make equipment or power supply damage, burn, even occur naked light initiation fire.Therefore, need special protective device in the electronic device, so that realize when short circuit appears in load can switching off load rapidly, cause further harm to avoid short circuit current.
The main following three kinds of modes of existing DC equipment load short circuit guard technology:
Temperature sensitivity device is connected in series in load current path; utilize big current during load short circuits to produce heat on temperature sensitivity device thus make temperature sensitivity device resistance become large or disconnect to protect load; this technology circuit is simple; but the reaction time is very slow; usually in a few second, not prompt enough to the protection of load, simultaneous temperature sensitive device is higher to loaded work piece current dependence; the selection of device is comparatively inconvenient, and versatility is not strong.
Adopt special load current sample circuit and short circuit latch control circuit to realize when load short circuits switching off load electric current to protect load, this technology can precisely and protect load timely, reaction time is usually within microsecond, but need in circuit to use operational amplifier, the integrated circuits such as microcontroller, circuit is complicated, cost is high, and integrated circuit there are certain requirements operating voltage, the system being equipped with special power supply to protective circuit may be needed in some special voltage occasion, circuit complexity and cost increase further, too increase the probability of protective circuit faults itself simultaneously, reliability decreases.
Employing discrete device carries out the short-circuit protection to load, and its theory diagram and circuit theory diagrams are respectively as shown in Figure 1 and Figure 2.This circuit is simple and reliable; reaction time is also very fast; flexibly, versatility is stronger, but this protective circuit cannot realize the latch of short-circuit condition for the utilization of discrete device and selection and comparison; when load short circuits, protective circuit can turn off load current path; but can reclose again at once, then turn off again, so move in circles; short circuit current can be there is by phased manner in such load, inadequate to load protection degree.For this reason, relay can be utilized to lock short-circuit condition, but circuit need use manual switchover, practicality is strong not.
Therefore, how with ball bearing made using realize fast, intelligent locking short-circuit condition, be current problem demanding prompt solution.
Utility model content
The utility model embodiment provides a kind of load short circuits protection circuit and DC suppling equipment, in order to solve the problem that cannot keep latched loads short-circuit condition that short circuit protection circuit of the prior art exists.
The load short circuits protection circuit that an embodiment of the present utility model provides, comprising: circuits for triggering 211, latch cicuit 212 and switching circuit 213; Circuits for triggering 211 are in parallel with load 22, latch cicuit 212 is in parallel with DC power supply 1, switching circuit 213 is series on the current path of load 22, and the output of circuits for triggering 211 is connected with the input of latch cicuit 212, and the output of latch cicuit 212 is connected with the input of switching circuit 213.
Circuits for triggering 211 export triggering signal to latch cicuit 212 when load 22 short circuit being detected, latch cicuit 212 output switching signal is to switching circuit 213, the current path of switching circuit 213 switching off load 22, latch cicuit 212 enters and keeps latch mode after receiving described triggering signal.
Described circuits for triggering 211 comprise transistor T3, diode D1, electric capacity C3, resistance R6, resistance R7; First pole of transistor T3 is connected to the negative pole of power supply 1 through electric capacity C3, second pole of transistor T3 is connected to the positive pole of power supply 1 through resistance R6, and the 3rd pole of transistor T3 is connected with the input of latch cicuit 212 as the output of circuits for triggering 211; Be serially connected with diode D1 and resistance R6 between the positive pole of power supply 1 and second pole of transistor T3, the positive pole of diode D1 is connected with the positive pole of power supply 1.
The current potential of second pole of transistor T3 is dragged down, and when the potential difference of first pole of transistor T3 and the second pole is greater than the conducting voltage of transistor T3, electric capacity C3 starts electric discharge, and transistor T3 conducting also exports triggering signal to latch cicuit 212.
Described transistor T3 is PNP type triode, the emitter of the first very PNP type triode of described transistor T3, the base stage of the second very PNP type triode of described transistor T3, the collector electrode of the 3rd very PNP type triode of described transistor T3; Or described transistor T3 is P channel MOS tube, the source electrode of the first very P channel MOS tube of described transistor T3, the grid of the second very P channel MOS tube of described transistor T3, the drain electrode of the 3rd very P channel MOS tube of described transistor T3.
Described latch cicuit 212 comprises transistor T1, transistor T2, electric capacity C1, electric capacity C2, resistance R1, resistance R2, resistance R3, resistance R4; First pole of transistor T2 is connected with the negative pole of power supply 1, second pole of transistor T2 is connected with circuits for triggering 211 output through resistance R4 as the input of latch cicuit 212, resistance R3 and electric capacity C2 is parallel with between first pole of transistor T2 and the second pole, 3rd pole of transistor T2 is connected with second pole of transistor T1, and the 3rd pole of transistor T2 is connected with switching circuit input as the output of latch cicuit 212; Be serially connected with resistance R1 between first pole of transistor T1 and power supply 1, the 3rd pole of transistor T1 is connected with second pole of transistor T2, is parallel with resistance R2 and electric capacity C1 between first pole of transistor T1 and the second pole.
After second pole of transistor T2 receives the triggering signal that circuits for triggering 211 export, transistor T2 and transistor T1 conducting successively, the 3rd pole output switching signal of transistor T2 is to switching circuit 213.
Described transistor T1 is PNP type triode or P channel MOS tube; The emitter of the first very PNP type triode of described transistor T1, the base stage of the second very PNP type triode of described transistor T1, the collector electrode of the 3rd very PNP type triode of described transistor T1.
The source electrode of the first very P channel MOS tube of described transistor T1, the grid of the second very P channel MOS tube of described transistor T1, the drain electrode of the 3rd very P channel MOS tube of described transistor T1.
Described transistor T2 is NPN type triode or N-channel MOS pipe; The emitter of the first very NPN type triode of described transistor T2, the base stage of the second very NPN type triode of described transistor T2, the collector electrode of the 3rd very NPN type triode of described transistor T2.
The source electrode of the first very N-channel MOS pipe of described transistor T2, the grid of the second very N-channel MOS pipe of described transistor T2, the drain electrode of the 3rd very N-channel MOS pipe of described transistor T2.
Described latch cicuit 212 comprises transistor SCR1, resistance R1, resistance R3, resistance R4 and electric capacity C2; Resistance R1 is connected between positive source and first pole of transistor SCR1, second pole of transistor SCR1 is connected with power cathode, resistance R4 is connected between the output of circuits for triggering 211 and the 3rd pole of transistor SCR1, resistance R3 connects and the 3rd between pole and power cathode of transistor SCR1, electric capacity C2 is in parallel with resistance R3, and the 3rd pole of transistor SCR1 is connected with the input of switching circuit 213 as the output of latch cicuit 212.
After 3rd pole of transistor SCR1 receives the triggering signal that circuits for triggering 211 export, transistor SCR1 conducting, output switching signal is to switching circuit 213.
Described transistor SCR1 is silicon-controlled device, the anode of the first very silicon-controlled device of described transistor SCR1, the negative electrode of the second very silicon-controlled device of described transistor SCR1, the control pole of the 3rd very silicon-controlled device of described transistor SCR1.
Described switching circuit 213 comprises metal-oxide-semiconductor M1 and resistance R5; Resistance R5 is connected between the output of latch cicuit and the grid of metal-oxide-semiconductor M1, and the source electrode of metal-oxide-semiconductor M1 and drain series are on the current path of load 22.
The grid of metal-oxide-semiconductor M1 receives the switching signal of latch cicuit 212 output, and metal-oxide-semiconductor M1 turns off.
The DC suppling equipment that an embodiment of the present utility model provides, comprising:
Load short circuits protection circuit 21 and load 22, load short circuits protection circuit 21 is connected between the load 22 of DC power supply 1 and DC suppling equipment, and described load short circuits protection circuit 21 is above-mentioned load short circuits protection circuit.
In above-described embodiment of the present utility model, when load is short-circuited, circuits for triggering 211 can send triggering signal to latch cicuit 212, and latch cicuit 212 enters and keeps latch mode, and to switching circuit 213 transmit button signal, make the current path of switching circuit 213 disconnecting consumers 22.The load short circuits protection circuit that the present embodiment provides; the simple cost of circuit is low; achieve when short-circuit conditions appears in load; locking short-circuit condition; proof load is in off state always; effectively protecting load, also can avoiding the damage that DC power supply 1 causes because of continuing to export big current simultaneously.
Accompanying drawing explanation
In order to be illustrated more clearly in the technical scheme in the utility model embodiment, below the accompanying drawing used required in describing embodiment is briefly introduced, apparently, accompanying drawing in the following describes is only embodiments more of the present utility model, for those of ordinary skill in the art, under the prerequisite not paying creative work, other accompanying drawing can also be obtained according to these accompanying drawings.
Fig. 1 is load short circuits protection circuit theory diagram of the prior art;
Fig. 2 is load short circuits protection circuit schematic diagram of the prior art;
The load short circuits protection circuit application scenarios schematic diagram that Fig. 3 provides for the utility model;
The load short circuits protection circuit theory diagram that Fig. 4 provides for the utility model;
A kind of circuits for triggering principle schematic that Fig. 5 a provides for the utility model;
A kind of latch cicuit principle schematic that Fig. 5 b provides for the utility model;
The another kind of latch cicuit principle schematic that Fig. 5 c provides for the utility model;
A kind of switching circuit principle schematic that Fig. 5 d provides for the utility model;
A kind of load short circuits protection circuit schematic diagram that Fig. 6 provides for the utility model;
The load short circuits protection circuit working state schematic representation that Fig. 7 provides for the utility model;
The another kind of load short circuits protection circuit schematic diagram that Fig. 8 provides for the utility model;
The another kind of load short circuits protection circuit schematic diagram that Fig. 9 provides for the utility model.
Embodiment
In order to make the purpose of this utility model, technical scheme and advantage clearly, below in conjunction with accompanying drawing, the utility model is described in further detail, obviously, described embodiment is only a part of embodiment of the utility model, instead of whole embodiments.Based on the embodiment in the utility model, those of ordinary skill in the art are not making other embodiments all obtained under creative work prerequisite, all belong to the scope of the utility model protection.
See Fig. 3, it is the load short circuits protection circuit application scenarios schematic diagram that the utility model provides.The load short circuits protection circuit 21 that the utility model provides is applied in the equipment 2 by DC power supply, and load short circuits protection circuit is connected between DC power supply 1 and load 22.If the load 22 in equipment 2 is short-circuited, load short circuits protection circuit 21 can cut off the circuit pathways of load 22, avoid load 22 to cause damage or initiation fire because of lasting big current, also can avoid the damage that DC power supply 1 causes because of lasting output big current simultaneously.
See Fig. 4, it is the theory diagram of the load short circuits protection circuit 21 that the utility model provides.This load short circuits protection circuit 21 can comprise: circuits for triggering 211, latch cicuit 212 and switching circuit 213.
Particularly, circuits for triggering 211 are in parallel with load 22, latch cicuit 212 is in parallel with DC power supply 1, switching circuit 213 is series on the current path of load 22, the output of circuits for triggering 211 is connected with the input of latch cicuit 212, and the output of latch cicuit 212 is connected with the input of switching circuit 213.
Circuits for triggering 211 export triggering signal to latch cicuit 212 when load 22 short circuit being detected, latch cicuit 212 output switching signal is to switching circuit 213, the current path of switching circuit 213 switching off load 22, latch cicuit 212 enters and keeps latch mode after receiving described triggering signal.
The theory diagram of the load short circuits protection circuit 21 according to Fig. 4, Fig. 5 a shows the schematic diagram of circuits for triggering 211, and Fig. 5 b and Fig. 5 c respectively illustrates the schematic diagram of two kinds of latch cicuits 212, and Fig. 5 d shows the schematic diagram of switching circuit 213.
See Fig. 5 a, circuits for triggering 211 comprise transistor T3, diode D1, electric capacity C3, resistance R6, resistance R7.First pole of transistor T3 is connected to the negative pole of power supply 1 through electric capacity C3, second pole of transistor T3 is connected to the positive pole of power supply 1 through resistance R6, and the 3rd pole of transistor T3 is connected with the input of latch cicuit 212 as the output of circuits for triggering 211; Be serially connected with diode D1 and resistance R6 between the positive pole of power supply 1 and second pole of transistor T3, the positive pole of diode D1 is connected with the positive pole of power supply 1.
The current potential of second pole of transistor T3 is dragged down, and when the potential difference of first pole of transistor T3 and the second pole is greater than the conducting voltage of transistor T3, electric capacity C3 starts electric discharge, and transistor T3 conducting also exports triggering signal to latch cicuit 212.
Alternatively, described transistor T3 is PNP type triode, so the emitter of first of transistor T3 the very PNP type triode, the base stage of the second very PNP type triode of transistor T3, the collector electrode of the 3rd very PNP type triode of transistor T3.
Alternatively, described transistor T3 also can be P channel MOS tube, so the source electrode of first of transistor T3 the very P channel MOS tube, the grid of the second very P channel MOS tube of transistor T3, the drain electrode of the 3rd very P channel MOS tube of transistor T3.
See Fig. 5 b, latch cicuit 212 comprises transistor T1, transistor T2, electric capacity C1, electric capacity C2, resistance R1, resistance R2, resistance R3, resistance R4.First pole of transistor T2 is connected with the negative pole of power supply 1, second pole of transistor T2 is connected with circuits for triggering 211 output through resistance R4 as the input of latch cicuit 212, resistance R3 and electric capacity C2 is parallel with between first pole of transistor T2 and the second pole, 3rd pole of transistor T2 is connected with second pole of transistor T1, and the 3rd pole of transistor T2 is connected with switching circuit input as the output of latch cicuit 212; Be serially connected with resistance R1 between first pole of transistor T1 and power supply 1, the 3rd pole of transistor T1 is connected with second pole of transistor T2, is parallel with resistance R2 and electric capacity C1 between first pole of transistor T1 and the second pole.
After second pole of transistor T2 receives the triggering signal that circuits for triggering 211 export, transistor T2 and transistor T1 conducting successively, the 3rd pole output switching signal of transistor T2 is to switching circuit 213.
Alternatively, described transistor T1 is PNP type triode, so the emitter of first of transistor T1 the very PNP type triode, the base stage of the second very PNP type triode of transistor T1, the collector electrode of the 3rd very PNP type triode of transistor T1.
Alternatively, described transistor T1 also can be P channel MOS tube, so the source electrode of first of transistor T1 the very P channel MOS tube, the grid of the second very P channel MOS tube of described transistor T1, the drain electrode of the 3rd very P channel MOS tube of described transistor T1.
Alternatively, described transistor T2 is NPN type triode, so the emitter of first of transistor T2 the very NPN type triode, the base stage of the second very NPN type triode of transistor T2, the collector electrode of the 3rd very NPN type triode of transistor T2.
Alternatively, described transistor T2 also can be N-channel MOS pipe, so the source electrode of first of transistor T2 the very N-channel MOS pipe, the grid of the second very N-channel MOS pipe of transistor T2, the drain electrode of the 3rd very N-channel MOS pipe of transistor T2.
See Fig. 5 c, latch cicuit 212 comprises transistor SCR1, resistance R1, resistance R3, resistance R4 and electric capacity C2.Resistance R1 is connected between positive source and first pole of transistor SCR1, second pole of transistor SCR1 is connected with power cathode, resistance R4 is connected between the output of circuits for triggering 211 and the 3rd pole of transistor SCR1, resistance R3 connects and the 3rd between pole and power cathode of transistor SCR1, electric capacity C2 is in parallel with resistance R3, and the 3rd pole of transistor SCR1 is connected with the input of switching circuit 213 as the output of latch cicuit 212.
After 3rd pole of transistor SCR1 receives the triggering signal that circuits for triggering 211 export, transistor SCR1 conducting, output switching signal is to switching circuit 213.
Preferably, described transistor SCR1 is silicon-controlled device, so the anode of first of transistor SCR1 the very silicon-controlled device, the negative electrode of the second very silicon-controlled device of transistor SCR1, the control pole of the 3rd very silicon-controlled device of transistor SCR1.
See Fig. 5 d, switching circuit 213 comprises metal-oxide-semiconductor M1 and resistance R5.Resistance R5 is connected between the output of latch cicuit and the grid of metal-oxide-semiconductor M1, and the source electrode of metal-oxide-semiconductor M1 and drain series are on the current path of load 22; The grid of metal-oxide-semiconductor M1 receives the switching signal of latch cicuit 212 output, and metal-oxide-semiconductor M1 turns off.
In above-described embodiment of the present utility model, achieve and lock short-circuit condition without the need to Non-follow control, proof load 22 is in off state always, effectively protects load, it also avoid the damage that DC power supply 1 causes because of continuing to export big current simultaneously.
The principle assumption diagram of a kind of load short circuits protection circuit 21 that the utility model embodiment provides is shown in conjunction with above-mentioned Fig. 5 a, Fig. 5 b and Fig. 5 d, Fig. 6.Wherein, transistor T1 is PNP type triode T11, and transistor T2 is NPN type triode T21, and transistor T3 is PNP type triode T31.
Below for the load short circuits protection circuit 21 shown in Fig. 6, its operation principle is described.
Load short circuits protection circuit shown in Fig. 5 a-Fig. 5 d has 4 kinds of operating states, is respectively initial condition, power-up state, normal operating conditions and guard mode, as shown in Figure 7.
Initial condition, when namely DC power supply 1 is not connected with equipment 2.Under this state, all non-stored charge of electric capacity C1, electric capacity C2, electric capacity C3, triode T11, triode T21, triode T31 and metal-oxide-semiconductor are all in cut-off state.
Power-up state, namely when DC power supply 1 is just connected with equipment 2.Power-up state is not a kind of stable state, can enter normal operating conditions after load short circuits protection circuit is operated in power-up state certain hour, or enters initial condition after DC power supply 1 and equipment 2 disconnect.
When load short circuits protection circuit is in power-up state, electric capacity C3 is charged gradually by diode D1 and resistance R7.Because there is conduction voltage drop when conducting between its positive and negative electrode in diode D1, and resistance R7 has electric current by time its two ends there is direct current pressure drop, therefore the current potential of B point is lower than the current potential of A point.For PNP type triode T31, the current potential of emitter is lower than base potential, and this triode is in cut-off state.Due to C point now no current process, and be connected with power cathode through pull down resistor R3, therefore, now C point current potential is 0 level.The emitter of NPN type triode T21 is owing to being connected with power cathode, and therefore the current potential of its emitter is 0 level, and again because its base potential is 0 level, therefore triode T21 is in cut-off state.The current potential of the collector electrode of PNP type triode T11 and C point current potential are 0 level, its emitter is connected with the positive pole of DC power supply 1 through pull-up resistor R1, therefore the current potential of its emitter is high level, its base stage is connected with the positive pole of DC power supply 1 through pull-up resistor R1 resistance R2, therefore the current potential of its base stage is high level, namely D point current potential is high level, so triode T11 is in cut-off state.Because D point current potential is high level, N-channel MOS pipe M1 is in conducting state, and thus load 22 is in power up.
In addition, between the emitter that electric capacity C1 is connected to triode T11 and base stage, between the emitter that electric capacity C2 is connected to triode T21 and base stage, its effect is and prevents powered on moment triode T11 and triode T11 from misleading.At powered on moment, between the emitter of triode T11 and base stage, there is potential difference, then charge to electric capacity C1, avoid triode T11 to mislead.In like manner, if there is potential difference between the emitter and base stage of powered on moment triode T21, then charge to electric capacity C2, avoid triode T21 to mislead.If triode T11, triode T21 mislead, then D point current potential becomes low level, N-channel MOS pipe M1 is disconnected, i.e. load 22 power-off when the non-short circuit of load.
Normal operating conditions, load short circuits protection circuit is entering normal operating conditions after the power-up state of certain hour.Now, electric capacity C3 is filled electricity, no longer continue charging, namely in load short circuits protection circuit just as open circuit, therefore diode D1 and resistance R7 no longer includes electric current and passes through, so A point current potential is equal with B point current potential, be V
in.And then triode T31 is in cut-off state, the current potential of C point is 0 level, and triode T11 and triode T21 is in cut-off state, and the current potential of D point is high level, and N-channel MOS pipe M1 is in conducting state, and load 22 normally works.
Guard mode, when namely load 22 is short-circuited.If load 22 is short-circuited, then the current potential of A point is dragged down, and makes the current potential of current potential higher than A point of B point, and namely the current potential of the emitter of triode T31 is higher than the current potential of base stage.When the current potential potential difference of B point and A point is greater than the conducting voltage of triode T31, triode T31 enters conducting state, and electric capacity C3 begins through the emitter junction of triode T31 and resistance R6 discharges.Due to triode T31 conducting, the current potential of the collector electrode of triode T31 raises, and exports triggering signal to latch cicuit, so the current potential of C point raises.When conducting voltage higher than triode T21 of the current potential of C point, triode T21 starts conducting.During due to NPN type triode T21 conducting, the potential difference between collector electrode and emitter is less, is generally 0.2V, so the current potential of D point is pulled to 0.2V, and then make PNP type triode T11 meet turn-on condition, triode T11 starts conducting.Current potential due to D point is less than the conducting voltage of N-channel MOS pipe M1, therefore metal-oxide-semiconductor M1 ends, and the current path of load 22 is disconnected.
Special instruction, makes triode T11 conducting after triode T21 conducting, and after triode T11 conducting, can maintain triode T21 and continue conducting.This is because when PNP type triode T11 conducting, the current potential of collector electrode is higher than base potential, and namely C point current potential is higher than D point current potential, and NPN type triode T21 conducting, need base potential to be greater than the current potential of collector electrode, namely C point current potential is higher than D point current potential.Therefore, load short circuits protection circuit in the embodiment that the utility model provides has and latches the function of short-circuit condition, once after trigger triode T11 and triode T21 conducting, just no longer need the triggering signal of circuits for triggering, just latch mode can be kept, until DC power supply 1 and equipment 2 disconnect.
After this, electric capacity C3 continues electric discharge until the electric charge release stored is complete, and when the electric charge release that electric capacity C3 stores is complete, triode T31 ends.
When DC power supply 1 disconnects with equipment 2, electric capacity C1 and electric capacity C2 starts electric discharge respectively by resistance R2, resistance R3, along with discharge process C point current potential reduces gradually, until the electric charge stored discharges complete completely, C point current potential becomes 0 level, and triode T21 and triode T11 enters cut-off state.Now, load short circuits protection circuit returns to initial condition.
The principle assumption diagram of the another kind of load short circuits protection circuit 21 that the utility model embodiment provides is shown in conjunction with above-mentioned Fig. 5 a, Fig. 5 b and Fig. 5 d, Fig. 8.Wherein, the metal-oxide-semiconductor M2 of transistor T1 to be the metal-oxide-semiconductor M3 of P raceway groove, transistor T2 be N raceway groove, transistor T3 is the metal-oxide-semiconductor M4 of P raceway groove.
The operating state of the load short circuits protection circuit shown in Fig. 8 is consistent with the operating state of the load short circuits protection circuit shown in Fig. 6, also can be represented by Fig. 7.
When power-up state, because the current potential of B point is lower than the current potential of A point, the metal-oxide-semiconductor M4 of P raceway groove is in cut-off state.Current potential due to C point is 0 level, and namely the current potential of the grid of the metal-oxide-semiconductor M2 of N raceway groove is 0 level, so metal-oxide-semiconductor M2 is in cut-off state.The grid of the metal-oxide-semiconductor M3 of P raceway groove connects the positive pole of DC power supply 1 by resistance R1, resistance R2, D point is high level, and therefore metal-oxide-semiconductor M3 is in cut-off state, and the metal-oxide-semiconductor M1 of N raceway groove is in conducting state.
When normal operating conditions, A point current potential is equal with B point current potential, and the metal-oxide-semiconductor M4 of P raceway groove is in cut-off state.The current potential of C point is 0 level, and metal-oxide-semiconductor M2 and metal-oxide-semiconductor M3 is in cut-off state.The current potential of D point is high level, and metal-oxide-semiconductor M1 is in conducting state, and load 22 normally works.
When guard mode, namely there is short circuit in load 22, then the current potential of A point is dragged down, and makes the current potential of current potential higher than A point of B point, and when the current potential potential difference of B point and A point is greater than the conducting voltage of metal-oxide-semiconductor M4, the metal-oxide-semiconductor M4 of P raceway groove is in conducting state.So the current potential of C point raises, when conducting voltage higher than metal-oxide-semiconductor M2 of the current potential of C point, the metal-oxide-semiconductor M2 of N raceway groove is in conducting state.During due to metal-oxide-semiconductor conducting, the potential difference between its drain electrode and source electrode is less, and thus the current potential of D point is pulled low to close to 0 level, so the metal-oxide-semiconductor M3 of P raceway groove is in conducting state.Current potential due to D point is less than the conducting voltage of N-channel MOS pipe M1, therefore metal-oxide-semiconductor M1 ends, and the current path of load 22 is disconnected.
In like manner, after metal-oxide-semiconductor M2 conducting, make metal-oxide-semiconductor M3 conducting, and metal-oxide-semiconductor M3 conducting can maintain metal-oxide-semiconductor M2 continuation conducting.
In conjunction with above-mentioned Fig. 5 a, Fig. 5 c and Fig. 5 d, the utility model embodiment still provides a kind of principle assumption diagram of load short circuits protection circuit 21, as shown in Figure 9.Wherein, circuits for triggering 211 are as good as with Fig. 8 with switching circuit 213, are replaced by by the latch cicuit 212 in Fig. 8 and are made up of silicon-controlled device SCR1, resistance R1, resistance R3, resistance R4 and electric capacity C2.
The operating state of the load short circuits protection circuit shown in Fig. 9 is consistent with the operating state of the load short circuits protection circuit shown in Fig. 6, Fig. 8, also can be represented by Fig. 7.
When power-up state, the current potential due to C point is 0 level, i.e. the control of silicon-controlled device SCR1 very 0 level, so silicon-controlled device SCR1 is in cut-off state.The anode of silicon-controlled device SCR1 is connected with the positive pole of DC power supply 1 by resistance R1, be high level, therefore the metal-oxide-semiconductor M1 of N raceway groove is in conducting state.
When normal operating conditions, the current potential due to C point is 0 level, and silicon-controlled device SCR1 is in cut-off state.The anode of silicon-controlled device SCR1 is connected with the positive pole of DC power supply 1 by resistance R1, be high level, therefore the metal-oxide-semiconductor M1 of N raceway groove is in conducting state.
When guard mode, namely there is short circuit in load 22, and the current potential of C point raises, and when conducting voltage higher than control silicon device SCR1 of the current potential of C point, controls silicon device SCR1 and start conducting.During due to control silicon device SCR1 conducting, the potential difference between its anode and negative electrode is less, and thus the current potential of D point is pulled low to close to 0 level, so the metal-oxide-semiconductor M1 of N raceway groove is in cut-off state, the current path of load 22 is disconnected.
In addition, after control silicon device SCR1 starts conducting, even if the voltage controlling pole reduces to 0, control silicon device SCR1 is still in conducting state.Therefore, when the electric charge release that electric capacity C3 stores is complete, the current potential of C point reduces to 0 level, and control silicon device SCR1 is still in conducting state, and metal-oxide-semiconductor M1 is still in cut-off state.
In above-described embodiment of the present utility model; the components and parts adopted can react rapidly when short circuit appears in load 22; time delay is short; and it is with low cost; achieve and lock short-circuit condition without the need to Non-follow control; proof load 22 is in off state always, effectively protects load, it also avoid the damage that DC power supply 1 causes because of continuing to export big current simultaneously.
The utility model additionally provides a kind of DC suppling equipment, cuts off load supplying power supply during for realizing load short circuits, and protection load is not damaged by big current.
This DC suppling equipment comprises: load short circuits protection circuit 21 and load 22.Wherein load short circuits protection circuit 21 is connected between the load 22 of DC power supply 1 and DC suppling equipment, and described load short circuits protection circuit 21 is the load short circuits protection circuit in above-described embodiment described in any one.
The DC suppling equipment that the utility model provides; apply the load short circuits protection circuit that the utility model provides; achieve and lock short-circuit condition without the need to Non-follow control; proof load 22 is in off state always; effectively protect load; it also avoid the damage that DC power supply 1 causes because of continuing to export big current, and time delay is short, with low cost simultaneously.
The utility model describes with reference to according to the flow chart of the method for the utility model embodiment, equipment (system) and computer program and/or block diagram.Should understand can by the combination of the flow process in each flow process in computer program instructions realization flow figure and/or block diagram and/or square frame and flow chart and/or block diagram and/or square frame.These computer program instructions can being provided to the processor of all-purpose computer, special-purpose computer, Embedded Processor or other programmable data processing device to produce a machine, making the instruction performed by the processor of computer or other programmable data processing device produce device for realizing the function of specifying in flow chart flow process or multiple flow process and/or block diagram square frame or multiple square frame.
These computer program instructions also can be stored in can in the computer-readable memory that works in a specific way of vectoring computer or other programmable data processing device, the instruction making to be stored in this computer-readable memory produces the manufacture comprising command device, and this command device realizes the function of specifying in flow chart flow process or multiple flow process and/or block diagram square frame or multiple square frame.
These computer program instructions also can be loaded in computer or other programmable data processing device, make on computer or other programmable devices, to perform sequence of operations step to produce computer implemented process, thus the instruction performed on computer or other programmable devices is provided for the step realizing the function of specifying in flow chart flow process or multiple flow process and/or block diagram square frame or multiple square frame.
Although described preferred embodiment of the present utility model, those skilled in the art once obtain the basic creative concept of cicada, then can make other change and amendment to these embodiments.So claims are intended to be interpreted as comprising preferred embodiment and falling into all changes and the amendment of the utility model scope.
Obviously, those skilled in the art can carry out various change and modification to the utility model and not depart from spirit and scope of the present utility model.Like this, if these amendments of the present utility model and modification belong within the scope of the utility model claim and equivalent technologies thereof, then the utility model is also intended to comprise these change and modification.
Claims (10)
1. a load short circuits protection circuit, described load short circuits protection circuit is connected between the load (22) of DC power supply (1) and DC suppling equipment, it is characterized in that, described load short circuits protection circuit comprises: circuits for triggering (211), latch cicuit (212) and switching circuit (213);
Circuits for triggering (211) are in parallel with load (22), latch cicuit (212) is in parallel with DC power supply (1), switching circuit (213) is series on the current path of load (22), the output of circuits for triggering (211) is connected with the input of latch cicuit (212), and the output of latch cicuit (212) is connected with the input of switching circuit (213).
2. load short circuits protection circuit as claimed in claim 1, it is characterized in that, described circuits for triggering (211) comprise transistor (T3), diode (D1), electric capacity (C3), resistance (R6), resistance (R7);
First pole of transistor (T3) is connected to the negative pole of power supply (1) through electric capacity (C3), second pole of transistor (T3) is connected to the positive pole of power supply (1) through resistance (R6), the 3rd pole of transistor (T3) is connected with the input of latch cicuit (212) as the output of circuits for triggering (211); Be serially connected with diode (D1) and resistance (R6) between the positive pole of power supply (1) and the second pole of transistor (T3), the positive pole of diode (D1) is connected with the positive pole of power supply (1).
3. load short circuits protection circuit as claimed in claim 2, it is characterized in that, described transistor (T3) is PNP type triode; Or described transistor (T3) is P channel MOS tube.
4. load short circuits protection circuit as claimed in claim 1, it is characterized in that, described latch cicuit (212) comprises transistor (T1), transistor (T2), electric capacity (C1), electric capacity (C2), resistance (R1), resistance (R2), resistance (R3), resistance (R4);
First pole of transistor (T2) is connected with the negative pole of power supply (1), second pole of transistor (T2) is connected with circuits for triggering (211) output through resistance (R4) as the input of latch cicuit (212), resistance (R3) and electric capacity (C2) is parallel with between first pole of transistor (T2) and the second pole, 3rd pole of transistor (T2) is connected with the second pole of transistor (T1), and the 3rd pole of transistor (T2) is connected with switching circuit input as the output of latch cicuit (212); Resistance (R1) is serially connected with between first pole of transistor (T1) and power supply (1), 3rd pole of transistor (T1) is connected with the second pole of transistor (T2), is parallel with resistance (R2) and electric capacity (C1) between the first pole of transistor (T1) and the second pole;
After second pole of transistor (T2) receives the triggering signal that circuits for triggering (211) export, transistor (T2) and transistor (T1) conducting successively, the 3rd pole output switching signal of transistor (T2) is to switching circuit (213).
5. load short circuits protection circuit as claimed in claim 4, it is characterized in that, described transistor (T1) is PNP type triode or P channel MOS tube.
6. load short circuits protection circuit as claimed in claim 4, it is characterized in that, described transistor (T2) is NPN type triode or N-channel MOS pipe.
7. load short circuits protection circuit as claimed in claim 1, it is characterized in that, described latch cicuit (212) comprises transistor (SCR1), resistance (R1), resistance (R3), resistance R4 and electric capacity (C2);
Resistance (R1) is connected between the first pole of positive source and transistor (SCR1), second pole of transistor (SCR1) is connected with power cathode, resistance (R4) is connected between the output of circuits for triggering (211) and the 3rd pole of transistor (SCR1), resistance (R3) connects and the 3rd between pole and power cathode of transistor (SCR1), electric capacity (C2) is in parallel with resistance (R3), and the 3rd pole of transistor (SCR1) is connected with the input of switching circuit (213) as the output of latch cicuit (212);
After 3rd pole of transistor (SCR1) receives the triggering signal that circuits for triggering (211) export, transistor (SCR1) conducting, output switching signal is to switching circuit (213).
8. load short circuits protection circuit as claimed in claim 7, it is characterized in that, described transistor (SCR1) is silicon-controlled device, the anode of the first very silicon-controlled device of described transistor (SCR1), the negative electrode of the second very silicon-controlled device of described transistor (SCR1), the control pole of the 3rd very silicon-controlled device of described transistor (SCR1).
9. load short circuits protection circuit as claimed in claim 1, it is characterized in that, described switching circuit (213) comprises metal-oxide-semiconductor (M1) and resistance (R5);
Resistance (R5) is connected between the output of latch cicuit and the grid of metal-oxide-semiconductor (M1), and the source electrode of metal-oxide-semiconductor (M1) and drain series are on the current path of load (22);
The grid of metal-oxide-semiconductor (M1) receives the switching signal that latch cicuit (212) exports, and metal-oxide-semiconductor (M1) turns off.
10. a DC suppling equipment, it is characterized in that, comprise: load short circuits protection circuit (21) and load (22), load short circuits protection circuit (21) is connected between the load (22) of DC power supply (1) and DC suppling equipment, and described load short circuits protection circuit (21) is the load short circuits protection circuit in claim 1 to 9 described in any one.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520856875.1U CN205178467U (en) | 2015-10-29 | 2015-10-29 | Load short circuit protection circuit and dc supply equipment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520856875.1U CN205178467U (en) | 2015-10-29 | 2015-10-29 | Load short circuit protection circuit and dc supply equipment |
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| Publication Number | Publication Date |
|---|---|
| CN205178467U true CN205178467U (en) | 2016-04-20 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201520856875.1U Expired - Fee Related CN205178467U (en) | 2015-10-29 | 2015-10-29 | Load short circuit protection circuit and dc supply equipment |
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| CN (1) | CN205178467U (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107732868A (en) * | 2017-09-21 | 2018-02-23 | 广州金升阳科技有限公司 | A kind of overcurrent protection control method and overcurrent protective device |
| CN107968379A (en) * | 2018-01-17 | 2018-04-27 | 攀枝花学院 | Solid-state direct-current current foldback circuit |
| CN108357453A (en) * | 2018-03-05 | 2018-08-03 | 浙江吉利汽车研究院有限公司 | A kind of collision detection circuit and system |
| CN112531650A (en) * | 2020-12-07 | 2021-03-19 | 华羿微电子股份有限公司 | From power MOSFET who takes short-circuit protection |
-
2015
- 2015-10-29 CN CN201520856875.1U patent/CN205178467U/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107732868A (en) * | 2017-09-21 | 2018-02-23 | 广州金升阳科技有限公司 | A kind of overcurrent protection control method and overcurrent protective device |
| CN107968379A (en) * | 2018-01-17 | 2018-04-27 | 攀枝花学院 | Solid-state direct-current current foldback circuit |
| CN107968379B (en) * | 2018-01-17 | 2024-05-17 | 攀枝花学院 | Solid-state direct current protection circuit |
| CN108357453A (en) * | 2018-03-05 | 2018-08-03 | 浙江吉利汽车研究院有限公司 | A kind of collision detection circuit and system |
| CN112531650A (en) * | 2020-12-07 | 2021-03-19 | 华羿微电子股份有限公司 | From power MOSFET who takes short-circuit protection |
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Granted publication date: 20160420 Termination date: 20211029 |