CN101944715A - Load short-circuit protection circuit - Google Patents

Load short-circuit protection circuit Download PDF

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Publication number
CN101944715A
CN101944715A CN 201010268117 CN201010268117A CN101944715A CN 101944715 A CN101944715 A CN 101944715A CN 201010268117 CN201010268117 CN 201010268117 CN 201010268117 A CN201010268117 A CN 201010268117A CN 101944715 A CN101944715 A CN 101944715A
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CN
China
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circuit
oxide
metal
semiconductor
load
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CN 201010268117
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Chinese (zh)
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CN101944715B (en
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林良有
黎志
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深圳拓邦股份有限公司
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Abstract

The invention relates to a load short-circuit protection circuit connected between a storage battery and a load circuit. The load short-circuit protection circuit comprises an MOS (Metal Oxide Semiconductor) tube protection circuit, a short-circuit detection circuit, a singlechip and an MOS tube switching circuit, wherein the MOS tube protection circuit is used for the reverse connection protection of the storage battery; the short-circuit detection circuit is used for detecting the short-circuit of the load circuit; the singlechip is used for sending out a switching signal according to a detection result of the short-circuit detection result; the MOS tube switching circuit is used for switching on or off the load circuit according to the switching signal; the short-circuit detection circuit comprises a comparer and a reference voltage generation circuit; the reference voltage generation circuit is connected to a first input end of the comparer; a source electrode of a first MOS tube of the MOS tube protection circuit is connected to a second input end of the comparer; and the output end of the comparer is connected to a first input end of the singlechip. The load short-circuit protection circuit is used for a load short-circuit protection circuit of a solar controller, has low cost, cannot increase the impedance of a load loop and has the function of eliminating instantaneous high voltage.

Description

The load short circuits protective circuit

Technical field

The present invention relates to protective circuit, more particularly, relate to a kind of load short circuits protective circuit that is used for controller for solar.

Background technology

Solar energy is distributed in all over the world, is one of energy that cleans most, and solar power generation always is a focus of energy research for this reason.Low-carbon (LC), the environmental protection campaign of recent years to advocate headed by the countries such as the U.S., solar power generation is more rapider than development in the past.

Solar power generation is made up of four parts: solar panel, storage battery and charging-discharging controller and load.And the function of charging-discharging controller has: (1) is charged to the electric weight of the solar panel charging modes according to storage battery in the storage battery; (2) electric weight of management of battery; (3) protection solar power system.

Solar charging/discharging controling appliance on the market is just like following characteristics are arranged: kind is various, and the application of middle low power is in the majority, especially is applied in above the road lamp system.For powerful system, the difficult point of one of them technology is exactly to realize the short-circuit protection function of load.

Because the instantaneous short circuit circuit of high-power system is bigger, some controllers on the market do not have the function of short-circuit protection.For the big-power solar controller that possesses short-circuit protection function, its scheme can reduce three kinds:

(1) scheme one: the most original short-circuit protection mode is exactly at the anode of storage battery or protective tube of negative terminal series connection, plays the effect of short-circuit protection by the fusing of protective tube;

Scheme one is simple in structure and be easy to realize, but shortcoming is obvious: it is high-power fast molten that protective tube requires, and cost is higher, requires the metal-oxide-semiconductor Chinese People's Anti-Japanese Military and Political College rush of current ability on the loop higher simultaneously, has increased the type selecting difficulty and the cost of metal-oxide-semiconductor device.

(2) scheme two: the inspection leakage resistance of a 1-5m Ω of series connection on loop of power circuit, and the impulse level that interrupts by short circuit of amplifier comparator circuit generation is given single-chip microcomputer then, comes the metal-oxide-semiconductor of cutoff circuit to realize short-circuit protection by single-chip microcomputer again; As shown in Figure 1.

Scheme two has been used the inspection leakage resistance, makes the impedance of load circuit increase, and has reduced the power supplying efficiency in loop.Simultaneously, powerful inspection leakage resistance cost is higher.

(3) scheme three: do not examine leakage resistance; after utilizing metal-oxide-semiconductor to pass through big electric current, the voltage of D end can be raised under the effect of internal driving, passes through a transistor circuit more cleverly again; produce to turn-off the voltage of metal-oxide-semiconductor, realize overcurrent protection and short-circuit protection in conjunction with the control of single-chip microcomputer.As shown in Figure 2.

In some external products (as the serial controller for solar of tower dragon of German Steca), application is arranged with scheme three similar structures.Fig. 3 is the short-circuit protection of the serial 30A controller for solar of tower dragon of German Steca and the circuit diagram of control section.When normally, single-chip microcomputer pin MCU controls output low level, thereby Q4 is by making the Q2 normally make the load circuit conducting, after the Q2 conducting, need only not short circuit of load end and do not have excessive electric current, drain voltage<0.5V of Q2 makes Q4 continue remain off, thereby keeps the conducting state of Q2; After Short-Circuit High Current occurring, the drain voltage of Q2 approaches the voltage of storage battery (10V-30V), and under the effect of the base stage of Q4 and emitter, the voltage of Q4 end is 0.7V, and the Q4 conducting causes Q2 to end, thereby has reached the purpose of short-circuit protection.Need automatic recovery behind the short-circuit protection: single-chip microcomputer pin MCU controls except possessing the I/O function, also has AD sampling function, single-chip microcomputer every a few tens of milliseconds this pin of once sampling (pin is unsettled input state during sampling, and sampling reverts to later output pin; During as AD sampling function, MCU control and R1 can think unsettled, therefore under the normal condition Q4 still by and the Q2 conducting), when single-chip microcomputer detects short-circuit protection (voltage of MCU control end>0.6V), MCU control pin is set to import vacant state, if short circuit exists so, the R6 two ends are short circuits, and Q4 continues conducting makes Q2 end; MCU control is exported a low level every 10 seconds, if short-circuit protection still exists, then Q4 continues conducting and makes not conducting of Q2; If short-circuit protection has been removed, Q4 will be by making the Q2 normally so.

Scheme three is relatively good, but pass through short-circuit test discovery to the serial 30A controller for solar of tower dragon of German Steca, the short circuit turn-off speed is too fast but do not have relative measures, (thickness according to wiring is different with length to cause the battery terminal place high pressure of moment to occur, instantaneous pressure is also different, can reach 70V even higher), and the withstand voltage device of metal-oxide-semiconductor is 55V, if the high pressure of this moment surpasses the withstand voltage limit of metal-oxide-semiconductor, then there is the possibility that punctures metal-oxide-semiconductor and damage device.

Summary of the invention

The technical problem to be solved in the present invention is; at the load short circuits protective circuit cost height that is used for controller for solar of prior art, the defective that reduces the power supplying efficiency in loop and be prone to instantaneous pressure damage device, provide the load short circuits protective circuit that is used for controller for solar that a kind of cost is low, can not increase the impedance of load circuit and have the elimination instantaneous pressure.

The technical solution adopted for the present invention to solve the technical problems is: constructs a kind of load short circuits protective circuit, is connected between storage battery and the load circuit, comprising:

The metal-oxide-semiconductor protective circuit that is used for the reverse connection of accumulator protection;

Be used to detect the short-circuit detecting circuit of load circuit short circuit;

Send the single-chip microcomputer of switching signal according to the testing result of described short-circuit detecting circuit; And

Make the metal-oxide-semiconductor switching circuit of described load circuit conducting or disconnection according to described switching signal.

In load short circuits protective circuit of the present invention; described short-circuit detecting circuit comprises comparator and generating circuit from reference voltage; described generating circuit from reference voltage is connected to the first input end of described comparator; the source electrode of first metal-oxide-semiconductor of described metal-oxide-semiconductor protective circuit is connected to second input of described comparator, and the output of described comparator is connected to the first input end of described single-chip microcomputer.

In load short circuits protective circuit of the present invention; the source electrode of described first metal-oxide-semiconductor is connected to described load circuit through second metal-oxide-semiconductor of described metal-oxide-semiconductor switching circuit; the grid of described first metal-oxide-semiconductor is connected to the positive pole of described storage battery, and the drain electrode of described first metal-oxide-semiconductor is connected to the negative pole of described storage battery.

In load short circuits protective circuit of the present invention, described short-circuit detecting circuit also comprises described comparator protective circuit, described comparator protective circuit comprises second voltage-stabiliser tube and second filter capacitor, the plus earth of described second voltage-stabiliser tube, negative electrode are connected to second input of described comparator; Described second filter capacitor is connected the two ends of described second voltage-stabiliser tube.

In load short circuits protective circuit of the present invention, described metal-oxide-semiconductor switching circuit also comprises the conducting shut-off circuit that makes the described second metal-oxide-semiconductor conducting or end; The source electrode of described second metal-oxide-semiconductor is connected to the source electrode of described first metal-oxide-semiconductor, and the drain electrode of described second metal-oxide-semiconductor is connected to described load circuit, and the grid of described second metal-oxide-semiconductor is connected to described conducting shut-off circuit.

In load short circuits protective circuit of the present invention, described conducting shut-off circuit is for adopting the drive circuit of drive IC.

In load short circuits protective circuit of the present invention, described conducting shut-off circuit comprises first triode, second triode, first diode and the 3rd triode, the emitter of described first triode is connected to the output of described single-chip microcomputer, the base stage of described first triode is connected to reference power supply, the collector electrode of described first triode is connected to the base stage of described second triode, the emitter of described second triode is connected to driving power, the collector electrode of described second triode is connected to the anode of described first diode, and the negative electrode of described first diode is connected to the grid of described second metal-oxide-semiconductor; The emitter of described the 3rd triode is connected to the grid of described second metal-oxide-semiconductor, and the base stage of described the 3rd triode is connected to the anode of described first diode, and the collector electrode of described the 3rd triode is connected to the source electrode of described first metal-oxide-semiconductor.

In load short circuits protective circuit of the present invention; described load short circuits protective circuit also comprises when described metal-oxide-semiconductor switching circuit disconnects described load circuit; be used to connect the testing circuit of recovery certainly of described load circuit; it is described that recovering testing circuit comprises the 3rd divider resistance and the 4th divider resistance certainly; the connected node of described the 3rd divider resistance and described the 4th divider resistance is connected to the negative pole of described storage battery; the other end of described the 3rd divider resistance is connected to the positive pole of described storage battery; the other end ground connection of described the 4th divider resistance, the connected node of described the 3rd divider resistance and described the 4th divider resistance is connected to second input of described single-chip microcomputer.

In load short circuits protective circuit of the present invention; described load short circuits protective circuit comprises that also high voltage transient suppresses circuit; described high voltage transient suppresses circuit and comprises that the input high voltage transient suppresses circuit and the output high voltage transient suppresses circuit; described input high voltage transient suppresses circuit and comprises the input electric capacity of voltage regulation; described output high voltage transient suppresses circuit and comprises second diode and output electric capacity of voltage regulation; described input electric capacity of voltage regulation is connected between the positive pole and negative pole of described storage battery; the negative electrode of described second diode is connected to the anode of described load circuit; the anode of described second diode is connected to the negative electrode of described load circuit, and described output electric capacity of voltage regulation is in parallel with described load circuit.

In load short circuits protective circuit of the present invention, described input high voltage transient suppresses circuit and also comprises the positive pole that is connected described storage battery and TVS pipe, piezo-resistance or the thermistor between the negative pole.

Implement load short circuits protective circuit of the present invention; have following beneficial effect: metal-oxide-semiconductor protective circuit of forming by two metal-oxide-semiconductors and metal-oxide-semiconductor switching circuit and short-circuit detecting circuit make that load short circuits protective circuit cost of the present invention is low; short-circuit detecting circuit detects the conduction impedance of metal-oxide-semiconductor protective circuit, can not increase the impedance of load circuit.

When the structure of short-circuit detecting circuit is accomplished response fast, also simplified the structure in bearing power loop.When the structure of metal-oxide-semiconductor protective circuit prevents reverse connection of accumulator to the destruction of load circuit and load short circuits protective circuit.Being provided with of comparator protective circuit protected the comparator in the short-circuit detecting circuit can not burnt owing to big electric current.Second metal-oxide-semiconductor that is arranged so that of metal-oxide-semiconductor switching circuit is made quick response by the conducting shut-off circuit to the signal of single-chip microcomputer.Adopt drive IC to drive second metal-oxide-semiconductor and given the user more choice.Adopt the conducting shut-off circuit cost of discrete device structure low, switching speed is adjustable.After the recovery testing circuit makes the load circuit short circuit, can recover automatically, reduce the number of times of short trouble, more near actual application requirements.The high pressure burr that occurs during short-circuit protection shutoff that high voltage transient has suppressed circuit for eliminating.Between the positive pole of storage battery and negative pole, connect TVS pipe, piezo-resistance or thermistor and can better eliminate the high pressure burr that occurs when short-circuit protection turn-offs.

Description of drawings

The invention will be further described below in conjunction with drawings and Examples, in the accompanying drawing:

Fig. 1 is a structural representation of examining the load short circuits protective circuit of leakage resistance in the prior art by series connection on loop of power circuit;

Fig. 2 is a structural representation of realizing the load short circuits protective circuit of automatic short-circuit protection in the prior art by the combination of metal-oxide-semiconductor and short circuit detection;

Fig. 3 is a circuit structure diagram of realizing the load short circuits protective circuit of automatic short-circuit protection in the prior art by the combination of metal-oxide-semiconductor and short circuit detection;

Fig. 4 is the circuit structure diagram of load short circuits protective circuit of the present invention;

Fig. 5 is the decision flow chart of the single-chip microcomputer of load short circuits protective circuit of the present invention.

Embodiment

In order to make purpose of the present invention, technical scheme and advantage clearer,, the present invention is further elaborated below in conjunction with drawings and Examples.Should be appreciated that specific embodiment described herein only in order to explanation the present invention, and be not used in qualification the present invention.

As shown in Figure 4; in the circuit structure diagram of load short circuits protective circuit of the present invention; described load short circuits protective circuit is connected between storage battery BT1 and the load circuit; described load short circuits protective circuit comprises metal-oxide-semiconductor protective circuit 1; short-circuit detecting circuit 2; single-chip microcomputer and metal-oxide-semiconductor switching circuit 3; metal-oxide-semiconductor protective circuit 1 is used for the reverse connection of accumulator protection; short-circuit detecting circuit 2 is used to detect the load circuit short circuit; single-chip microcomputer is used for sending switching signal according to the testing result of short-circuit detecting circuit 2, and metal-oxide-semiconductor switching circuit 3 is used for making described load circuit conducting or disconnection according to described switching signal.During the work of this load short circuits protective circuit, guarantee the work that just connects of storage battery by metal-oxide-semiconductor protective circuit 1, as reverse connection of accumulator then the first metal-oxide-semiconductor Q6 in the metal-oxide-semiconductor protective circuit 1 play the effect of reverse connecting protection by causing whole storage battery and load circuit not to be worked; Short-circuit detecting circuit 2 judges whether big electric current by the conduction impedance that detects the first metal-oxide-semiconductor Q6 and the time of electric current judges that by load circuit load circuit is denied short circuit greatly; as occurring big electric current on the load circuit and continuing for some time (as 2ms; make a distinction with the impulse current of load powered on moment; impulse current also may be higher than operating current; but the duration is all very short; the microsecond level); then testing result is issued single-chip microcomputer; single-chip microcomputer cuts out the second metal-oxide-semiconductor Q4 in the metal-oxide-semiconductor switching circuit 3 with the disconnecting consumers circuit according to described testing result, plays the load short circuits protective effect.Metal-oxide-semiconductor protective circuit of forming by two metal-oxide-semiconductors 1 and metal-oxide-semiconductor switching circuit 3 and short-circuit detecting circuit 2 make that load short circuits protective circuit cost of the present invention is low; short-circuit detecting circuit detects the conduction impedance of metal-oxide-semiconductor protective circuit, can not increase the impedance of load circuit.

As shown in Figure 4; in the circuit structure diagram of load short circuits protective circuit of the present invention; short-circuit detecting circuit 2 comprises comparator U2D and generating circuit from reference voltage; generating circuit from reference voltage is connected to the first input end of comparator U2D; the source electrode of the first metal-oxide-semiconductor Q6 of metal-oxide-semiconductor protective circuit 1 is connected to second input of comparator U2D, and the output of comparator U2D is connected to the first input end of single-chip microcomputer.The operation principle of this short-circuit detecting circuit 2 is as follows: the short-circuit detecting point is the source electrode of the first metal-oxide-semiconductor Q6, and detecting resistance is the conduction impedance of the first metal-oxide-semiconductor Q6, generally in the 3-10 milliohm; The reference voltage of comparator U2D is produced by the first divider resistance R28, the second divider resistance R30 dividing potential drop.When being short-circuited, the source electrode of the first metal-oxide-semiconductor Q6 can produce bigger voltage, when electric current is raised to a certain degree, the voltage of the source electrode of the first metal-oxide-semiconductor Q6 also is higher than reference voltage thereupon, make that the output INT2 of comparator U2D is a low level, after single-chip microcomputer detects INT2 trailing edge is arranged, control metal-oxide-semiconductor switching circuit 3 disconnecting consumers circuit by Q4_SW immediately.The circuit design main points of this part are mainly choose (being obtained by the first divider resistance R28 and the second divider resistance R30 dividing potential drop) of reference voltage, reference voltage is relevant with conduction impedance and the operating current of the first metal-oxide-semiconductor Q6, for example: the conduction impedance of the first metal-oxide-semiconductor Q6 is 6 milliohms, operating current is at 90A, and reference voltage is 6*90mV=0.54V so.Certainly, the conduction impedance of the first metal-oxide-semiconductor Q6 is not an accurate numerical value, and change along with the change of temperature, so in design, need design with worst situation, for example, the maximum operating temperature of the first metal-oxide-semiconductor Q6 is 100 ℃, under this temperature, the highest conduction impedance of the first metal-oxide-semiconductor Q6 is 6.5 milliohms, requires in all cases, and the operating current of short circuit all is higher than 60A, reference voltage then will be chosen 6.5*60mV=0.39V so, when the first metal-oxide-semiconductor Q6 temperature was low, operating current also can increase, and can calculate the maximum actuation electric current under this reference voltage so, whether check design to meet the requirements: the minimum temperature of supposing first metal-oxide-semiconductor Q6 work is-30 ℃, minimum conduction impedance is 4.3 milliohms, Zui Da operating current=390mV/4.3m Ω=90.7A so, and check adheres to specification.When the structure of short-circuit detecting circuit is accomplished response fast, also simplified the structure in bearing power loop.

As shown in Figure 4; in the circuit structure diagram of load short circuits protective circuit of the present invention; the source electrode of the first metal-oxide-semiconductor Q6 is connected to described load circuit through the second metal-oxide-semiconductor Q4 of metal-oxide-semiconductor switching circuit 3; the grid of the first metal-oxide-semiconductor Q6 is connected to the positive pole of described storage battery, and the drain electrode of the first metal-oxide-semiconductor Q6 is connected to the negative pole of described storage battery.Metal-oxide-semiconductor protective circuit 1 among the figure also comprises the first current-limiting resistance R8 and the first voltage-stabiliser tube Z5, and the negative electrode of the first voltage-stabiliser tube Z5 is connected to the positive pole of described storage battery by the first current-limiting resistance R8, and the anode of the first voltage-stabiliser tube Z5 is connected to the source electrode of the first metal-oxide-semiconductor Q6; The grid of the first metal-oxide-semiconductor Q6 is connected to the positive pole of described storage battery by the first current-limiting resistance R8.Therefore high-power system generally all adopts this structure.When accumulator positive connect, the first metal-oxide-semiconductor Q6 was normally under the effect of the first current-limiting resistance R8 and the first voltage-stabiliser tube Z5.When this structure of metal-oxide-semiconductor protective circuit can well prevent reverse connection of accumulator to the destruction of load circuit and load short circuits protective circuit.

As shown in Figure 4, in the circuit structure diagram of load short circuits protective circuit of the present invention, short-circuit detecting circuit 2 also comprises described comparator protective circuit, described comparator protective circuit comprises the second voltage-stabiliser tube Z8 and the second filter capacitor C13, the plus earth of the second voltage-stabiliser tube Z8, negative electrode are connected to second input of comparator U2D; The second filter capacitor C13 is connected the two ends of the second voltage-stabiliser tube Z8.When reverse connection of accumulator, have bigger negative pressure and be carried on the protective resistance R29, the second voltage-stabiliser tube Z8 is stabilized in the voltage of comparator U2D second input-0.6V~-0.7V and not being damaged; When above-mentioned situation takes place when, have bigger voltage and be carried in protective resistance R29 two ends, do not burn for the needs that satisfy power consumption, protective resistance R29 should choose power more than 0.25W reaches.Being provided with of comparator protective circuit protected the comparator in the short-circuit detecting circuit can not burnt owing to big electric current.

As shown in Figure 4, in the circuit structure diagram of load short circuits protective circuit of the present invention, metal-oxide-semiconductor switching circuit 3 also comprises the conducting shut-off circuit that makes the second metal-oxide-semiconductor Q4 conducting or end; The source electrode of the second metal-oxide-semiconductor Q4 is connected to the source electrode of the first metal-oxide-semiconductor Q6, and the drain electrode of the second metal-oxide-semiconductor Q4 is connected to load circuit, and the grid of the second metal-oxide-semiconductor Q4 is connected to described conducting shut-off circuit.Described conducting shut-off circuit also can adopt drive circuit or other drive circuits of building with discrete device of drive IC.The conducting shut-off circuit of building if any discrete device can be to comprise the first triode T4, the second triode T5, the first diode D3 and the 3rd triode T8, the emitter of the first triode T4 is connected to the output of described single-chip microcomputer, the base stage of the first triode T4 is connected to reference power supply, the collector electrode of the first triode T4 is connected to the base stage of the second triode T5, the emitter of the second triode T5 is connected to driving power VSW, the collector electrode of the second triode T5 is connected to the anode of the first diode D3, and the negative electrode of the first diode D3 is connected to the grid of the second metal-oxide-semiconductor Q4; The emitter of the 3rd triode T8 is connected to the grid of the second metal-oxide-semiconductor Q4, and the base stage of the 3rd triode T8 is connected to the anode of the first diode D3, and the collector electrode of the 3rd triode T8 is connected to the source electrode of the described first metal-oxide-semiconductor Q6.Second metal-oxide-semiconductor that is arranged so that of metal-oxide-semiconductor switching circuit 3 is made quick response by the conducting shut-off circuit to the signal of single-chip microcomputer.Adopt drive IC to drive second metal-oxide-semiconductor and given the user more choice.Adopt the conducting shut-off circuit cost of discrete device structure low, switching speed is adjustable.This conducting shut-off circuit also can comprise the second current-limiting resistance R9, the first biasing resistor R10, the 3rd current-limiting resistance R11, the 4th current-limiting resistance R12 and the second biasing resistor R60, the emitter of the first triode T4 is connected to the output of described single-chip microcomputer by the second current-limiting resistance R9, the negative electrode of the first diode D3 is connected to the grid of the second metal-oxide-semiconductor Q4 by the 3rd current-limiting resistance R11, the first biasing resistor R10 is connected between the emitter and base stage of the second triode T5, the emitter of the 3rd triode T8 is connected to the grid of the second metal-oxide-semiconductor Q4 by the 4th current-limiting resistance R12, and the second biasing resistor R60 is connected between the base stage and collector electrode of the 3rd triode T8.Metal-oxide-semiconductor switching circuit 3 operation principles are as follows: when needing the conducting load circuit, Q4_SW is by the single-chip microcomputer output low level, the then first triode T4 conducting, the second triode T5 conducting under the effect of the first biasing resistor R10, driving power VSW provides driving voltage (for example+10V), this voltage is loaded on the grid of the second metal-oxide-semiconductor Q4 through the second triode T5, the first diode D3, the 3rd current-limiting resistance R11 path, make grid driving voltage (for example 9.3V) be arranged, thereby make the second metal-oxide-semiconductor Q4 conducting source electrode; When needing the disconnecting consumers loop, Q4_SW exports high level by single-chip microcomputer, then the first triode T4 and the second triode T5 end, driving power VSW, the second triode T5, the first diode D3, the 3rd current-limiting resistance R11 path is not conducting, at the second biasing resistor R60, the 3rd triode T8, under the effect of the 4th current-limiting resistance R12 circuit structure, the 3rd triode T8 conducting, junction capacitance between the grid source electrode of the second metal-oxide-semiconductor Q4 is by the second biasing resistor R60, the 3rd triode T8, the 4th current-limiting resistance R12 circuit discharging, make the grid voltage between source electrodes of the second metal-oxide-semiconductor Q4 become 0V (under the situation of VSW=10V), realize that the second metal-oxide-semiconductor Q4 disconnects by 9.3V.In this circuit; the 3rd current-limiting resistance R11 controls the speed of the second metal-oxide-semiconductor Q4 conducting; and the 4th current-limiting resistance R12 controls the speed that the second metal-oxide-semiconductor Q4 closes; the second metal-oxide-semiconductor Q4 is not damaged because switching speed is slow when recovering in order to reach at short-circuit protection; the 3rd current-limiting resistance R11 and the 4th current-limiting resistance R12 are generally hundreds of ohm; even tens ohm, conducting and the quick closedown second metal-oxide-semiconductor Q4 so fast, the general second metal-oxide-semiconductor Q4 drive signal V GSRise time and fall time in 10 microseconds.

As shown in Figure 4; in the circuit structure diagram of load short circuits protective circuit of the present invention; described load short circuits protective circuit also comprises when metal-oxide-semiconductor switching circuit 3 disconnects described load circuit; be used to connect the testing circuit of recovery certainly 4 of described load circuit; comprise the 3rd divider resistance R39 and the 4th divider resistance R40 from recovering testing circuit 4; the connected node of the 3rd divider resistance R39 and the 4th divider resistance R40 is connected to the negative pole of described storage battery; the other end of the 3rd divider resistance R39 is connected to the positive pole of described storage battery; the other end ground connection of the 4th divider resistance R40, the connected node of the 3rd divider resistance R39 and the 4th divider resistance R4 is connected to second input of described single-chip microcomputer.Testing circuit 4 operation principles are as follows from recovering: the voltage of DISC_VOL is divided into two kinds of situations, and when the load circuit short circuit, the voltage of storage battery directly is loaded into the 4th divider resistance R40 end, and after the voltage stabilizing of the 3rd voltage-stabiliser tube Z1, DISC_VOL is 5.6V; When load circuit disconnects when being unsettled, the magnitude of voltage of DISC_VOL is the partial pressure value of the 3rd divider resistance R39 and the 4th divider resistance R40, and for example the 3rd divider resistance R39 is 560K, and the 4th divider resistance R40 is 56K, the highest 33V that is no more than of accumulator voltage, then DISC_VOL<3V.Self-healing process is as follows: after load circuit was short-circuited protection, single-chip microcomputer was surveyed the voltage of DISC_VOL, when still more than or equal to 5V, then keeps the off state of the second metal-oxide-semiconductor Q4; The voltage of DISC_VOL illustrates that then short circuit line has been disconnected during less than 4V, and the conducting load circuit has been realized recovering certainly again.After the recovery testing circuit makes the load circuit short circuit, can recover automatically, reduce the number of times of short trouble, more near actual application requirements.

As shown in Figure 4; in the circuit structure diagram of load short circuits protective circuit of the present invention; described load short circuits protective circuit comprises that also high voltage transient suppresses circuit; high voltage transient suppresses circuit and comprises that the input high voltage transient suppresses circuit and the output high voltage transient suppresses circuit; the input high voltage transient suppresses circuit and comprises input electric capacity of voltage regulation C28; the output high voltage transient suppresses circuit and comprises the second diode D2 and output electric capacity of voltage regulation C29; input electric capacity of voltage regulation C28 is connected between the positive pole and negative pole of described storage battery; the negative electrode of the second diode D2 is connected to the anode of described load circuit; the anode of the second diode D2 is connected to the negative electrode of described load circuit, and C29 is in parallel with described load circuit for the output electric capacity of voltage regulation.The input high voltage transient suppresses circuit and also comprises the positive pole that is connected described storage battery and TVS pipe, piezo-resistance or the thermistor between the negative pole.The operation principle that high voltage transient suppresses circuit is as follows: the moment that short-circuit protection turn-offs; the high pressure burr appears (greater than 50V; continue 1-10us); reason is: continue living inductance of the cable of solar energy wiring exists; after passing through, turn-offs fast in big electric current; the effect of living inductance of continuing can produce higher transient voltage, and serious may damage devices such as metal-oxide-semiconductor.In order to absorb this transient voltage, accelerate the second diode D2 and the output electric capacity of voltage regulation C29 of quick-recovery at the load output, the second diode D2 is used for water conservancy diversion, and output electric capacity of voltage regulation C29 is used for absorbing burr; Add TVS pipe and input electric capacity of voltage regulation C28 at the storage battery input, be used for absorbing the high pressure burr of moment.The TVS pipe that high voltage transient suppresses circuit also can adopt devices such as piezo-resistance or thermistor, perhaps removes this device, strengthens the appearance value of input electric capacity of voltage regulation C28 and handles.

The concrete workflow of this load short circuits protective circuit is described: when being short-circuited moment below by the decision flow chart of the single-chip microcomputer of the load short circuits protective circuit of Fig. 5; short circuit current sharply rises; after being raised to the operating current of comparator U2D definition; comparator U2D can produce the first input end that a low level is given single-chip microcomputer; single-chip microcomputer judges whether this short circuit current continues for some time (as 2ms; make a distinction with the impulse current of load circuit powered on moment; impulse current also may be higher than operating current; but the duration is all very short; the microsecond level); if then carry out the action of short-circuit protection: the disconnecting consumers circuit loop, failure code is reported to the police.Recovery behind the short-circuit protection in case voltage is lower than 4V, illustrates that then the short circuit of load circuit has recovered, the conducting again of load circuit loop by surveying the voltage of DISC_VOL.

The above only is embodiments of the invention; be not so limit claim of the present invention; every equivalent structure transformation that utilizes specification of the present invention and accompanying drawing content to be done, or directly or indirectly be used in other relevant technical fields, all in like manner be included in the scope of patent protection of the present invention.

Claims (10)

1. a load short circuits protective circuit is connected between storage battery and the load circuit, it is characterized in that, comprising:
The metal-oxide-semiconductor protective circuit (1) that is used for the reverse connection of accumulator protection;
Be used to detect the short-circuit detecting circuit (2) of load circuit short circuit;
Send the single-chip microcomputer of switching signal according to the testing result of described short-circuit detecting circuit (2); And
Make the metal-oxide-semiconductor switching circuit (3) of described load circuit conducting or disconnection according to described switching signal.
2. load short circuits protective circuit according to claim 1; it is characterized in that; described short-circuit detecting circuit (2) comprises comparator (U2D) and generating circuit from reference voltage; described generating circuit from reference voltage is connected to the first input end of described comparator (U2D); the source electrode of first metal-oxide-semiconductor (Q6) of described metal-oxide-semiconductor protective circuit (1) is connected to second input of described comparator (U2D), and the output of described comparator (U2D) is connected to the first input end of described single-chip microcomputer.
3. load short circuits protective circuit according to claim 2; it is characterized in that; the source electrode of described first metal-oxide-semiconductor (Q6) is connected to described load circuit through second metal-oxide-semiconductor (Q4) of described metal-oxide-semiconductor switching circuit (3); the grid of described first metal-oxide-semiconductor (Q6) is connected to the positive pole of described storage battery, and the drain electrode of described first metal-oxide-semiconductor (Q6) is connected to the negative pole of described storage battery.
4. load short circuits protective circuit according to claim 2, it is characterized in that, described short-circuit detecting circuit (2) also comprises described comparator protective circuit, described comparator protective circuit comprises second voltage-stabiliser tube (Z8) and second filter capacitor (C13), the plus earth of described second voltage-stabiliser tube (Z8), negative electrode are connected to second input of described comparator (U2D); Described second filter capacitor (C13) is connected the two ends of described second voltage-stabiliser tube (Z8).
5. load short circuits protective circuit according to claim 2 is characterized in that, described metal-oxide-semiconductor switching circuit (3) also comprises the conducting shut-off circuit that makes described second metal-oxide-semiconductor (Q4) conducting or end;
The source electrode of described second metal-oxide-semiconductor (Q4) is connected to the source electrode of described first metal-oxide-semiconductor (Q6), and the drain electrode of described metal-oxide-semiconductor (Q4) is connected to described load circuit, and the grid of described metal-oxide-semiconductor (Q4) is connected to described conducting shut-off circuit.
6. load short circuits protective circuit according to claim 5 is characterized in that, described conducting shut-off circuit is for adopting the drive circuit of drive IC.
7. load short circuits protective circuit according to claim 6 is characterized in that,
Described conducting shut-off circuit comprises first triode (T4), second triode (T5), first diode (D3) and the 3rd triode (T8), the emitter of described first triode (T4) is connected to the output of described single-chip microcomputer, the base stage of described first triode (T4) is connected to reference power supply, the collector electrode of described first triode (T4) is connected to the base stage of described second triode (T5), the emitter of described second triode (T5) is connected to driving power (VSW), the collector electrode of described second triode (T5) is connected to the anode of described first diode (D3), and the negative electrode of described first diode (D3) is connected to the grid of described metal-oxide-semiconductor (Q4); The emitter of described the 3rd triode (T8) is connected to the grid of described metal-oxide-semiconductor (Q4), the base stage of described the 3rd triode (T8) is connected to the anode of described first diode (D3), and the collector electrode of described the 3rd triode (T8) is connected to the source electrode of described first metal-oxide-semiconductor (Q6).
8. load short circuits protective circuit according to claim 1; it is characterized in that; described load short circuits protective circuit also comprises when described metal-oxide-semiconductor switching circuit disconnects described load circuit; be used to connect the testing circuit of recovery certainly (4) of described load circuit; it is described that recovering testing circuit (4) comprises the 3rd divider resistance (R39) and the 4th divider resistance (R40) certainly; the connected node of described the 3rd divider resistance (R39) and described the 4th divider resistance (R40) is connected to the negative pole of described storage battery; the other end of described the 3rd divider resistance (R39) is connected to the positive pole of described storage battery; the other end ground connection of described the 4th divider resistance (R40), the connected node of described the 3rd divider resistance (R39) and described the 4th divider resistance (R40) is connected to second input of described single-chip microcomputer.
9. load short circuits protective circuit according to claim 1; it is characterized in that; described load short circuits protective circuit comprises that also high voltage transient suppresses circuit; described high voltage transient suppresses circuit and comprises that the input high voltage transient suppresses circuit and the output high voltage transient suppresses circuit; described input high voltage transient suppresses circuit and comprises input electric capacity of voltage regulation (C28); described output high voltage transient suppresses circuit and comprises second diode (D2) and output electric capacity of voltage regulation (C29); described input electric capacity of voltage regulation (C28) is connected between the positive pole and negative pole of described storage battery; the negative electrode of described second diode (D2) is connected to the anode of described load circuit; the anode of described second diode (D2) is connected to the negative electrode of described load circuit, and described output electric capacity of voltage regulation (C29) is in parallel with described load circuit.
10. load short circuits protective circuit according to claim 9 is characterized in that, described input high voltage transient suppresses circuit and also comprises the positive pole that is connected described storage battery and TVS pipe, piezo-resistance or the thermistor between the negative pole.
CN 201010268117 2010-08-31 2010-08-31 Load short-circuit protection circuit CN101944715B (en)

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CN102790374A (en) * 2011-12-19 2012-11-21 洛阳理工学院 Short circuit protection circuit
CN102969701A (en) * 2012-11-30 2013-03-13 桂林海博泰克电子科技有限公司 Battery protection and sparkle suppression circuit
CN102996885A (en) * 2012-10-19 2013-03-27 宁波长壁流体动力科技有限公司 Protection drive circuit of small-power electromagnetic coil
WO2014134781A1 (en) * 2013-03-05 2014-09-12 Xiang Zhiyong Control device and method for overcurrent or short-circuit protection of electronic cigarette
CN104052085A (en) * 2013-03-11 2014-09-17 深圳硕日新能源科技有限公司 Solar-energy controller drive circuit with short-circuit protection function
CN104466891A (en) * 2014-12-17 2015-03-25 浪潮电子信息产业股份有限公司 Short-circuit protection device and method based on Feiteng platform
CN104485706A (en) * 2014-12-09 2015-04-01 上海中兴派能能源科技有限公司 Discharge circuit for lithium battery pack
CN104795807A (en) * 2015-04-16 2015-07-22 上海空间电源研究所 High-reliability current protecting circuit for astronavigation
CN106199299A (en) * 2015-05-27 2016-12-07 英飞凌科技股份有限公司 The system and method for the short-circuit detecting in load bearing chain
CN106410740A (en) * 2016-06-23 2017-02-15 北京全路通信信号研究设计院集团有限公司 Power supply port protective circuit
CN104331141B (en) * 2013-07-22 2017-04-12 纬创资通股份有限公司 Overcurrent protection circuit and server using the same
CN108845240A (en) * 2018-04-27 2018-11-20 上海电机学院 A kind of SCM Based automatic testing circuit system
CN110165740A (en) * 2019-06-03 2019-08-23 重庆斯微奇电子技术有限公司 A kind of battery protecting circuit and power supply unit
CN110275058A (en) * 2019-06-20 2019-09-24 华立科技股份有限公司 The communication module overload identification protection circuit and method of intelligent electric energy meter
CN110361621A (en) * 2018-04-11 2019-10-22 佛山市顺德区美的电热电器制造有限公司 Load detecting circuit and method

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CN102790374A (en) * 2011-12-19 2012-11-21 洛阳理工学院 Short circuit protection circuit
CN102996885B (en) * 2012-10-19 2014-10-08 宁波长壁流体动力科技有限公司 Protection drive circuit of small-power electromagnetic coil
CN102996885A (en) * 2012-10-19 2013-03-27 宁波长壁流体动力科技有限公司 Protection drive circuit of small-power electromagnetic coil
CN102969701A (en) * 2012-11-30 2013-03-13 桂林海博泰克电子科技有限公司 Battery protection and sparkle suppression circuit
WO2014134781A1 (en) * 2013-03-05 2014-09-12 Xiang Zhiyong Control device and method for overcurrent or short-circuit protection of electronic cigarette
CN104052085B (en) * 2013-03-11 2016-09-07 深圳硕日新能源科技有限公司 A kind of controller for solar drive circuit of band short-circuit protection
CN104052085A (en) * 2013-03-11 2014-09-17 深圳硕日新能源科技有限公司 Solar-energy controller drive circuit with short-circuit protection function
CN104331141B (en) * 2013-07-22 2017-04-12 纬创资通股份有限公司 Overcurrent protection circuit and server using the same
CN104485706A (en) * 2014-12-09 2015-04-01 上海中兴派能能源科技有限公司 Discharge circuit for lithium battery pack
CN104466891A (en) * 2014-12-17 2015-03-25 浪潮电子信息产业股份有限公司 Short-circuit protection device and method based on Feiteng platform
CN104795807A (en) * 2015-04-16 2015-07-22 上海空间电源研究所 High-reliability current protecting circuit for astronavigation
CN104795807B (en) * 2015-04-16 2018-02-06 上海空间电源研究所 A kind of aerospace high reliability current protecting circuit
CN106199299B (en) * 2015-05-27 2019-08-23 英飞凌科技股份有限公司 System and method for the short-circuit detecting in load bearing chain
CN106199299A (en) * 2015-05-27 2016-12-07 英飞凌科技股份有限公司 The system and method for the short-circuit detecting in load bearing chain
CN106410740A (en) * 2016-06-23 2017-02-15 北京全路通信信号研究设计院集团有限公司 Power supply port protective circuit
CN110361621A (en) * 2018-04-11 2019-10-22 佛山市顺德区美的电热电器制造有限公司 Load detecting circuit and method
CN108845240A (en) * 2018-04-27 2018-11-20 上海电机学院 A kind of SCM Based automatic testing circuit system
CN110165740A (en) * 2019-06-03 2019-08-23 重庆斯微奇电子技术有限公司 A kind of battery protecting circuit and power supply unit
CN110165740B (en) * 2019-06-03 2020-08-25 重庆斯微奇电子技术有限公司 Battery protection circuit and power supply device
CN110275058A (en) * 2019-06-20 2019-09-24 华立科技股份有限公司 The communication module overload identification protection circuit and method of intelligent electric energy meter

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