CN101944715A - Load short-circuit protection circuit - Google Patents

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 instantaneoushigh voltage.

Description

Load short circuit protection

FIELD

[0001] The present invention relates to a protection circuit, and more particularly, to a load short circuit protection for the solar controller.

Background technique

[0002] Solar located around the world, is one of the cleanest energy, solar energy for this purpose has always been a hot topic of research. In recent years the United States and other countries, led by advocating low-carbon, green environmental movement, the development of solar power more rapidly than ever.

[0003] Solar power consists of four parts: a solar cell panel, and a battery charge controller and the load. And the charging and discharging functions of the controller are: (1) the power of the solar panel to charge the battery according to the battery charging; (2) control of the battery power; (3) to protect the solar power generation system.

Solar [0004] market if charge and discharge controller having the following characteristics: a wide variety, mostly small and medium power applications, particular application in the above system lights. For high-power system, which is a technical and difficult to achieve short-circuit protection of the load.

[0005] short circuit due to a momentary power larger systems, a number of market controller without short-circuit protection. For solar power controller includes a short-circuit protection functions, which can be summarized into three programs:

[0006] (1) a program: the most primitive way to short-circuit protection positive terminal or negative terminal of a fuse in series to the short-circuit protection functions through the action of the fuse tube battery;

[0007] a simple structure and is easy to implement embodiment, but obvious disadvantages: high power fuse requirements of fast-acting, high cost, while required loop current of the MOS transistor anti-big shocks, the MOS transistor device increases Selection of the difficulty and cost.

[0008] (2) Scheme II: In the power loop a series sense resistor 1_5πιΩ, and then generate a pulse level by a short circuit interruption to the microcontroller of the operational amplifier comparator circuit, then by the microcontroller to turn off MOS circuit tubes short-circuit protection; as shown in FIG.

[0009] The second scheme uses a current-sense resistor, such that the impedance of the load circuit increases, reducing the efficiency of the power supply circuit. Meanwhile, the higher cost of high-power sense resistor.

[0010] (3) Scheme III: Do not check the flow resistance, the use of the MOS transistor by a large current, under the effect of internal impedance of the voltage D terminal will raise, and through a more subtle transistor circuit that generates a turn-off MOS transistor voltage, in conjunction with control of the microcontroller to overcurrent protection and short circuit protection. as shown in picture 2.

Three similar structure [0011] and programs have application in a number of foreign products (such as Germany Steca tower dragon series solar controller) in. FIG 3 is a circuit diagram showing a short-circuit protection and the control portion of the column Germany Steca long series of solar controller 30A. When the normally-on, the microcontroller MCU to control the output pin low, Q4 is turned off so that the normal Q2 so that the load circuit is turned on, Q2 is turned back, as long as the load is not short-circuited end without excessive current drain of Q2 voltage <0. 5V such Q4 remain off, thereby maintaining the conduction state and Q2; when large short circuit currents, the drain voltage of Q2 is close to the battery voltage (10V-30V), the base and the emitter of Q4 in under the action of the pole, the voltage of terminal Q4 0. 7V, Q4 is turned off results in Q2, so as to achieve the purpose of short-circuit protection. After the short circuit protection requires automatic recovery: microcontroller pin MCU control

4 In addition to I / O functions, but also an AD sampling function, several tens of milliseconds sampled once the pin (input sampling is left unconnected state, after the restoration of the sampling interval the microcontroller output pins; AD as a sampling function, MCU control and Rl can be considered vacant, and therefore under normal circumstances or Q4 is turned off and Q2 is oN), when the microcontroller detects that a short-circuit protection (MCU control terminal voltage> 0. 6V), MCU control pins as inputs floating state, if the short circuit continues to exist, R6 is short-circuited at both ends, so that Q2 Q4 is turned off to continue; controlling the MCU outputs a low level every 10 seconds, if the short circuit protection persists, then Q4 is turned on to continue such Q2 nonconductive; if short circuit protection is removed, then Q4 is turned off so that Q2 will be turned on correctly.

[0012] Option Three is better, but the short-circuit test by the German Steca series of Taron 30A solar controller found a short-circuit turn-off too fast but there is no corresponding measures, resulting in the emergence of battery terminals of the high-pressure moment (according to wiring of different thickness and length, high-voltage transient is not the same, up to 70V or higher), the device withstand voltage MOS transistor of 55V, the instant high pressure exceeds the pressure limit MOS tube, there is a breakdown of MOS tube may damage the device.

SUMMARY

[0013] The present invention is to solve the technical problem, the short circuit protector for high-cost solar controller, reducing the efficiency of the power supply circuit and the high-voltage transient damage to the device prone to defects of the prior art, to provide a low cost , without increasing the impedance of the load circuit and a short circuit protector for high-voltage transient elimination solar controller.

[0014] aspect of the present invention to solve the technical problem are: to construct a circuit protection circuit connected between the battery and the load circuit, which comprises:

[0015] a reverse battery protection circuit protection MOS transistor;

[0016] The short circuit detecting circuit for detecting a short circuit of a load;

[0017] Microcontroller switching signal issued from the detection result of said short circuit detecting circuit; and

[0018] MOS switch tube circuit said load circuit turned on or off according to the switching signal causes.

[0019] In the short circuit protector according to the present invention, the short circuit detecting circuit includes a comparator and a reference voltage generating circuit, the reference voltage generating circuit is connected to a first input terminal of said comparator, said MOS source of the first MOS transistor circuit protection tube is connected to the second input of the comparator, the comparator output is connected to a first input of the microcontroller.

[0020] In the short circuit protector according to the present invention, the source electrode of the first MOS transistor through said second MOS transistor circuit MOS switch tube connected to the load circuit, said first MOS transistor a gate connected to the positive electrode of the battery, a drain of the first MOS transistor is connected to the negative electrode of the battery.

[0021] In the short circuit protector according to the present invention, the short circuit detecting circuit further comprises a comparator of the protection circuit, said protection circuit comprises a second comparator and a second zener diode filter capacitor, said first the anode is grounded, the cathode of the zener diode is connected to the input of a second comparator; and the second filter capacitor connected across said second regulator tube.

[0022] In the short circuit protector according to the present invention, the switching circuit further comprises a MOS transistor of said second MOS transistor is turned off or the circuit is turned off; source of the second MOS transistor is connected to the source electrode of the first MOS transistor, a drain of the second MOS transistor is connected to the load circuit, the gate of the second MOS transistor is connected to the conduction circuit closed.

5 [0023] In the short circuit protector according to the present invention, employing a conductive closed circuit driver IC driving circuit.

[0024] In the short circuit protector according to the present invention, the closed circuit comprises a first conduction transistor, a second transistor, a third transistor and a first diode, said first the emitter of the transistor is connected to an output of the microcontroller, the first base of the transistor is connected to a standard power source, the collector of the first transistor is connected to the second transistor a base, an emitter of said second transistor connected to a driving power source, the collector of the second transistor is connected to the anode of the first diode, the first diode cathode is connected to the gate of the second MOS transistor; a third transistor emitter connected to the gate of the second MOS transistor, said third transistor base connected to the first two the anode of the diode, the collector of the third transistor connected to the source electrode of the first MOS transistor.

[0025] In the short circuit protector according to the present invention, the short circuit protection circuit further comprises a load when the switching circuit turns off the MOS transistor load circuit, said load circuit for switching the self-restoration detection circuit, said detection circuit comprises a resettable third voltage dividing resistor and a fourth voltage dividing resistor, said third voltage dividing resistor and the fourth resistor partial connection node connected to the cathode of the battery, the first the other end of the third resistor is connected to the positive electrode of the battery, the other end of the fourth voltage dividing resistors, the third voltage dividing resistor and the fourth resistor partial connection node is connected to the microcontroller a second input terminal.

[0026] In the short circuit protector according to the present invention, the load short-circuit protection circuit further includes a transient suppression circuit high voltage, the high voltage transient suppression circuit includes a high voltage transient suppression circuit input and an output high voltage transient suppression circuit the input transient suppression circuit includes a high voltage regulator input capacitance, the output high voltage transient suppression circuit includes a second voltage regulator diode and an output capacitor, said input capacitor is connected in a positive regulator of the battery and the negative electrode between the cathode of the second diode is connected to the anode of the load circuit, the anode of the second diode cathode is connected to the load circuit, the output capacitor and the load circuit voltage regulator in parallel.

[0027] In the short circuit protector according to the present invention, the input transient suppression circuit further includes a high voltage is connected between the positive and negative electrodes of the battery of the TVS diode, a varistor or a thermistor.

[0028] The circuit protection circuit according to the present invention has the following advantages: the MOS transistor protection circuit and a MOS transistor switch circuit and the short circuit detecting circuit by the double MOS tube composed of such a low-load short protection circuit the cost of the present invention, the short circuit detecting circuit detecting MOS transistor on-resistance of the protective circuit, without increasing the impedance of the load circuit.

Structure [0029] The short-circuit detection circuit be fast response, but also simplifies the structure of the power load circuit. MOS transistor structure protection circuit prevents damage to the load circuit and the short circuit protector when reverse battery. Comparator protection circuit protection circuit short-circuit detection comparator does not burned because of the large current. MOS transistor switching circuit is provided such that the second MOS transistor is turned off by the circuit to respond quickly to signal the microcontroller. Using a second driving MOS transistor driver IC gives the user more choice. Low cost circuit is turned off using the separating device configuration, the switching speed is adjustable. Recovery from such a load detecting circuit can be automatically restored after the short circuit, reducing the number of short-circuit failure, closer to the actual application requirements. High voltage transient suppression circuit to eliminate the high-voltage spikes occurring when the short circuit protection off. Between the positive and negative electrodes of the battery with a TVS diode, a varistor or thermistor may be better to eliminate the high-voltage spikes occurring when the short circuit protection off.

BRIEF DESCRIPTION

[0030] The accompanying drawings and the following embodiments of the present invention is further illustrated drawings in which:

[0031] FIG. 1 is a schematic structural diagram of a power series loop circuit protection circuit of the sense resistor by the prior art;

[0032] FIG. 2 is a schematic structural diagram of a short-circuit protection circuit automatically load short-circuit protection of the prior art by a combination of short-circuiting MOS transistor and detection;

[0033] FIG. 3 is a circuit configuration diagram of a load short-circuit protection automatic short circuit protection by a combination of the prior art MOS transistor and the short circuit detection;

[0034] FIG. 4 is a circuit configuration diagram of the short circuit protector of the present invention;

[0035] FIG. 5 is a flowchart showing determination microcontroller circuit protection circuit of the present invention.

Detailed ways

[0036] To make the objectives, technical solutions and advantages of the present invention will become more apparent hereinafter in conjunction with the accompanying drawings and embodiments of the present invention will be further described in detail. It should be understood that the specific embodiments described herein are only intended to illustrate the present invention and are not intended to limit the present invention.

[0037] As shown, in the circuit configuration diagram of a load short-circuit protection of the present invention, the load short-circuit protection circuit is connected between the battery and the load circuit 4 BTl, the load circuit comprises a MOS transistor short-circuit protection circuit protection 1, the short circuit detecting circuit 2, the microcontroller 2 and the load circuit for detecting short-circuiting MOS transistor switch circuit 3, M0S tube reverse battery protection circuit for protection, short-circuit detection circuit, microcontroller for sending the detection result of the short circuit detecting circuit 2 switching signal, MOS tube 3 a circuit for the switching circuit on or off according to the load signal causes the switch. This work load short-circuit protection circuit, the protection circuit 1 by the MOS transistor being connected to the battery to ensure the work, such as reverse battery protection circuit of the MOS transistor 1 in a first MOS transistor Q6 turns off cause the entire battery and the load circuit does not work, play a counter connection protective effects; short detection circuit 2 is turned on by detecting a first MOS transistor Q6 of the impedance is determined whether a time of large current and a large current through the load circuit to determine whether a short-circuit load circuit, a large current such as occurs for a period of the load circuit time (e.g., 2ms, electric shock and a load current regions separate moment, inrush current may be higher than the operating current, but very short duration, microseconds), then the detection results to the microcontroller, the microcontroller according to the a detection result of said MOS transistor switch circuit 3 turn off the second MOS transistor Q4 in order to disconnect the load circuit, a load short-circuit protection functions. MOS circuit by a double pipe protection MOS transistor and a MOS transistor composed of a switching circuit 3 and the low load so that the present invention is the cost of the short protection circuit short circuit detecting circuit 2, the short-circuit detecting circuit protection circuit MOS transistor on-resistance, without increasing the load impedance circuit.

[0038] As shown, in the circuit configuration diagram of a load short-circuit protection of the present invention, the short-circuit detection circuit 2 includes a comparator U2D and the reference voltage generating circuit 4, the reference voltage generating circuit is connected to a first input of comparator U2D a second input terminal, a first MOS MOS tube of a protection circuit source Q6 is connected to the comparator U2D, the output of comparator U2D is connected to a first input of the microcontroller. Working principle of the short circuit detecting circuit 2 is as follows: The first short detection point source MOS transistor Q6 is, as a first sensing resistor impedance MOS transistor Q6 is turned on, usually in 3-10 milliohms; reference voltage comparator U2D a first voltage dividing resistor R28, a second voltage dividing resistor R30 voltage divider. When a short circuit occurs, a first electrode of the MOS transistor Q6 source will have a greater voltage, when the current rose to a certain extent, a first voltage source MOS transistor Q6 will also higher than the reference voltage, so that the comparator the output of U2D is low INT2, INT2 microcontroller to detect the falling edge, immediately switching circuit controlled by the MOS transistor Q4_SW 3 off the load circuit. The portion of the circuit design elements mainly selected reference voltage (obtained from the first voltage dividing resistor R28 and a second voltage dividing resistor R30 divided voltage), the reference voltage and on-resistance of the first MOS transistor Q6 and the current operation related, e.g. : on-resistance of a first MOS transistor Q6 6 milliohms 9OA current operation, then the reference voltage of 6 * 90mV = 0. 54V. Of course, the on-resistance of the first MOS transistor Q6 is not an exact value, and change with changes in temperature, so the time required to design the worst case be designed, for example, the

7 a MOS transistor Q6 is the maximum operating temperature is 100 ° C, at this temperature, the maximum on-resistance of a first MOS transistor Q6 is 6.5 milliohms, required in all cases, the operation of short-circuit current higher than 60A , then the reference voltage will have to select 6. 5 * 60mV = 0. 39V, when the temperature is low the first MOS transistor Q6, the current operation will also rise, then to calculate the maximum operating current at the reference voltage to compliance test design: a first MOS transistor Q6 is assumed that the minimum operating temperature of -30 ° C, the smallest on-resistance of 4.3 milliohms, then the maximum operating current = 390mV / 4 3m Ω = 90. 7Α. inspection meets the design requirements. Short circuit detecting circuit configuration to achieve rapid response, but also simplifies the structure of the power load circuit.

[0039] As shown in FIG. 4, in the circuit configuration diagram of a load short-circuit protection of the present invention, the source of the first MOS transistor Q6 is switching circuit via the MOS transistor Q4 3 second MOS transistor is connected to the load circuit, the gate of the first MOS transistor Q6 is connected to the positive electrode of the battery, the drain of the first MOS transistor Q6 is connected to the negative electrode of the battery. MOS transistor protection circuit of Figure 1 further comprises a first current limiting resistor R8 and zener diode Ζ5 first, a first zener diode connected to the cathode through Ζ5 first current limiting resistor R8 to the positive electrode of the battery, a first stable Ζ5 anode pressure pipe is connected to the source of the first MOS transistor Q6 is; the gate of a first MOS transistor Q6 is connected to the positive electrode of the battery through a first current limiting resistor R8. Thus high power systems typically use this configuration. When the battery positive contact, a first MOS transistor Q6 under the action of a first current limiting resistor R8 and a first regulator Ζ5 a normally conducting state. MOS transistor protection circuit of such a configuration can well prevent damage to the load circuit and load short circuit when reverse battery protection.

[0040] As shown in FIG. 4, in the circuit configuration diagram of a load short-circuit protection of the present invention, the short circuit detecting circuit 2 further includes a protection circuit of the comparator, said comparator circuit comprises a second zener diode protection and Ζ8 second filtering capacitor C13, a second zener diode Ζ8 anode is grounded, and a cathode connected to a second input of comparator U2D terminal; a second filter capacitor C13 is connected across a second zener diode Ζ8. When reverse battery, a large negative pressure will be loaded on the protective resistor R29, a second voltage regulator Ζ8 the second input of comparator U2D is stable at -0. 6V~-0. 7V without damage ; when this occurs, there will be a large voltage applied across the protective resistor R29, the power consumption in order to meet needs without burning protective resistor R29 should be selected 0. 25W power and above. Comparator protection circuit protection circuit short-circuit detection comparator does not burned because of the large current.

[0041] As shown, in the circuit configuration diagram of a load short-circuit protection of the present invention, the MOS transistor 3 further comprises a switching circuit 4 of the second MOS transistor Q4 is turned off or the circuit is turned off; a second MOS transistor source of Q4 is connected to the source electrode of the first MOS transistor Q6, the drain of the second MOS transistor Q4 is connected to the load circuit, the gate of the second MOS transistor Q4 is connected to the conduction circuit closed. The circuit may also be turned off drive circuit or other separating device drive circuit built in an IC. If the separation device is built turned off circuit may include a first transistor Τ4, a second transistor Τ5, a first transistor and a third diode D3 Τ8, transmitting a first electrode of the transistor [tau] 4 connected to the output of the microcontroller, a first transistor base connected to Τ4 standard power supply, the collector of the first transistor is connected to the base of the second Τ4 Τ5 pole transistor, a second transistor Τ5 the emitter is connected to the VSW drive power, the collector of the second transistor is connected to the anode of the first Τ5 diode D3, the cathode of the first diode D3 is connected to the gate of the second MOS transistor Q4; third Τ8 transistor emitter connected to the gate of the second MOS transistor Q4, the base of the third transistor Τ8 connected to the anode of the first diode D3 is connected to the collector of the third transistor to the Τ8 a source of said first MOS transistor Q6 is. MOS transistor switch circuit 3 is provided such that the second MOS transistor is turned off by the circuit to respond quickly to signal the microcontroller. Using a second driving MOS transistor driver IC gives the user more choice. Low cost circuit is turned off using the separating device configuration, the switching speed is adjustable. This closed circuit may further comprise conducting a second current limiting resistor R9, a first bias resistor R10, a third current-limiting resistor R11, a current limiting resistor R12 and the fourth a second bias resistor R60, a first transistor Τ4 emitter connected to an output of the microcontroller through a second current limiting resistor R9, a first cathode of the diode D3 is connected to the gate of the second MOS transistor Q4 through the third current limiting resistor Rll, a first bias resistor RlO is connected between the emitter and the base of the second transistor T5, the emitter of the third transistor T8 is connected to the gate of the second MOS transistor Q4 through the fourth current limiting resistor R12, a second bias resistor R60 a third transistor T8 is connected between the base and the collector. 3 MOS transistor switching circuit works as follows: When turned on the load circuit requires, Q4_Sff by the microcontroller outputs a low level, the first transistor T4 is turned on, under the action of the first bias resistor RlO second transistor T5 turned on, power supply VSW driving voltage (e.g., + 10V), the second voltage through the transistor T5, a first diode D3, the third current limiting resistor Rll loaded path to the gate of the second MOS transistor Q4 , so that the gate-to-source drive voltage (e.g. 9. 3V), so that the second MOS transistor Q4 is turned on; when the need to disconnect the load circuit, Q4_SW by the microcontroller outputs a high level, the first transistor T4 and a second transistor T5 is turned off, the VSW drive power, a second transistor T5, a first diode D3, the third current limiting resistor Rll path is not conducting, the second bias resistor R60, the third three- diode T8, under the action of the current limiting resistor R12 fourth circuit configuration, the third transistor T8 is turned on, the second MOS transistor junction capacitance between the Q4 gate-source via a second bias resistor R60, a third three-pole (in the case of VSW = IOV) tubes T8, the current limiting resistor R12 fourth discharge circuit, the second MOS transistor between the gate-source voltage of Q4 is changed OV 9. 3V Implementation of the second MOS transistor Q4 is turned off. In this circuit, the third control current limiting resistor Rll second MOS transistor Q4 is turned on the speed limiting resistor R12 and the fourth MOS transistor Q4 for controlling the second speed of closing, in order to short-circuit protection and self-healing second MOS since the switching transistor Q4 is slow and not damaged, the third and fourth current-limiting resistor Rll limiting resistor R12 - generally a few hundred ohms, or even tens of ohms, which can quickly turn on and off the second MOS transistor Q4 quickly, Usually the rise time of the second MOS transistor Q4 driving signal Ves and fall times less than 10 microseconds.

[0042] As shown in FIG. 4, in the circuit configuration diagram of a load short-circuit protection of the present invention, the load when the short circuit protection circuit further comprises a MOS transistor switch circuit 3 is turned off when said load circuit, for turning on the a load circuit of said self-recovery detecting circuit 4, since the resumption of the detection circuit 4 includes a third voltage dividing resistor R39 and a fourth voltage dividing resistors R40, R39 of the third voltage dividing resistor and the fourth voltage dividing resistor R40 is connected to the connection node the negative electrode of the battery, the other end of the third voltage-dividing resistor R39 is connected to the positive electrode of the battery, the other end of the fourth voltage dividing resistors R40 and R39 of the third voltage dividing resistor and the fourth voltage dividing resistor R4 is connected to the connection node the second input of the microcontroller. Recovery from the detection circuit 4 operates as follows: The voltage DISC_V0L divided into two cases, when the load short circuit, the battery voltage is loaded directly onto the end of the fourth voltage dividing resistors R40, the zener diode Zl regulator after the third, DISC_V0L to 5. 6V; i.e. when the load circuit is disconnected vacant, DISC_ VOL is the voltage value of the third voltage dividing resistors R39 and R40 of the fourth voltage dividing resistors, for example, a third voltage dividing resistor R39 is 560K, the first resistor R40 quarter of 56K, the maximum battery terminal voltage does not exceed 33V, the DISC_V0L <3V. Self-recovery procedure is as follows: When the load short-circuit protection circuit, the voltage detection DISC_V0L the microcontroller, while still not less than 5V, the remains off the second MOS transistor Q4; DISC_V0L voltage is less than 4V, then the short-circuit line is disconnected, the load circuit is turned on again, to achieve the self-recovery. Recovery from such a load detecting circuit can be automatically restored after the short circuit, reducing the number of short-circuit failure, closer to the actual application requirements.

[0043] As shown in FIG. 4, in the circuit configuration diagram of a load short-circuit protection of the present invention, the load short-circuit protection circuit further includes a transient suppression circuit high voltage, high voltage transient suppression circuit includes an input transient suppression circuit and a high voltage high voltage transient suppression circuit output, the input high voltage transient suppression circuit includes an input voltage stabilizing capacitor C28, the output of high voltage transient suppression circuit includes a second diode D2 and an output stabilizing capacitance-C29, the input voltage stabilizing capacitor C28 is connected between the battery between the positive and negative electrodes, the cathode of the second diode D2 is connected to the anode of the load circuit, the anode of the second diode D2 is connected to the cathode of the load circuit, the output of the regulator and the load capacitor C29 parallel circuit. Input high voltage transient suppression circuit further comprises a TVS diode, a varistor or thermistor is connected between the positive and negative electrodes of the battery. High voltage transient suppression circuit works as follows: instantaneous short circuit protection off, voltage spikes can occur (greater than 50V, continuous I-IOus), because: a solar connection cables there exist inductance of relay, when a large current by flash turn off, following the action of inductances will produce

9 high instantaneous voltage, serious damage may be MOS transistors and other devices. In order to absorb the instantaneous voltage at the output of the second diode D2 and the load output stabilizing capacitance C29 plus fast recovery diode D2 to the second guide, to absorb the output voltage stabilizing capacitor C29 burr; the battery TVS diode plus input terminal and the input voltage stabilizing capacitor C28, to absorb the momentary high-voltage spikes. TVS tube high voltage transient suppression circuit may also be employed such as a thermistor or varistor device, or the device is removed, increase the capacitance of the capacitor C28 to the regulator input process.

When the sharp rise in the instantaneous short circuit, short-circuit current, the operation of the current comparator U2D raised defined: [0044] The following explains a specific work flow of the short circuit protector is a flowchart of determination by the MCU circuit protection circuit of FIG. 5 , comparator U2D generates a low level to the first input of a microcontroller, the microcontroller determines whether the short-circuit current for a period of time (e.g., 2ms, electric shock and the load circuit current moment separate regions, a high inrush current may also be in the current operation, but the duration is very short, microsecond), if yes, operation of short-circuit protection: disconnecting the load circuit loop fault code alarm. Recovery short circuit protection by detecting a voltage DISC_V0L, once the voltage is lower than 4V, then the short circuit has been restored to the load circuit, the load circuit loop is turned on again.

[0045] Other related art technologies described above are only embodiments of the present invention, not intended to limit the scope of the present invention, all utilize the present specification and drawings taken transform equivalent structures, or applied directly or indirectly shall fall within the scope of protection of the present invention.

Claims (10)

1. A load short-circuit protection circuit connected between the battery and the load circuit, characterized by comprising: a reverse battery protection circuit protection MOS transistor (1); means for detecting a short circuit of a load short-circuit detection circuit (2) ; (2) emits a detection result signal according to the single-chip switch short detection circuit; and an MOS transistor switching circuit in accordance with the switching signal causes the load circuit is turned on or off (3).
2. 2. The circuit protection circuit according to claim 1, wherein said short circuit detecting circuit (2) comprises a comparator (U2D) and a reference voltage generating circuit, the reference voltage generating circuit connected to said comparator (U2D) a first input terminal, the protection circuit M0S tube (1) a first source M0S tube (Q6 are) is connected to said comparator (U2D) to a second input of the comparator (U2D ) the output is connected to a first input of the microcontroller.
3. The circuit protection circuit according to claim 2, characterized in that the source of the first tube M0S (Q6 are) pole through the tube M0S switching circuit (3) a second tube M0S (Q4) is connected to the said load circuit, a gate of the first tube M0S (Q6 are) connected to the positive electrode of the battery, a drain of the first tube M0S (Q6 are) connected to the negative electrode of the battery.
4. 4. The circuit protection circuit according to claim 2, wherein said short circuit detecting circuit (2) further comprising a protection circuit of the comparator, said comparator comprises a second zener diode protection circuit (Z8) the anode is grounded and a second filter capacitor (C13), said second zener diode (Z8), and a cathode connected to said comparator (U2D) a second input terminal; the second filtering capacitor (C13) is connected in both ends of the second zener diode (Z8) of.
5. 5. The circuit protection circuit according to claim 2, wherein said tube M0S switching circuit (3) further comprises said second pipe M0S (Q4) is turned off or the circuit is turned off; the said second tube M0S source (Q4) is connected to said first tube M0S (Q6 are) a source, a drain pipe M0S said first (Q4) is connected to said load circuit, said first tube M0S ( Q4) is connected to the gate circuit is turned off.
6. 6. The circuit protection circuit as claimed in claim 5, wherein said conductive circuit is closed the driver circuit of the driver IC.
7. 7. The circuit protection circuit according to claim 6, wherein the shutdown circuit comprises a first conduction transistor (T4), a second transistor (T5), a first diode (D3 ) and a third transistor (T8), said first transistor (T4) emitter connected to an output of the microcontroller, the first transistor (T4) the base is connected to a standard power the collector of the first transistor (T4) is connected to the second transistor (T5) the base of the second transistor (T5) is connected to the emitter of the driving power source (the VSW) , the collector of the second transistor (T5) is connected to said first diode (D3) the anode of said first diode (D3) is connected to the cathode of said first tube M0S (Q4 ) gate; said third transistor (T8) emitter connected to the gate of said first tube M0S (Q4), said third transistor (T8) is connected to said second base a diode (D3) of the anode, the collector of the third transistor (T8) is connected to the first tube M0S (Q6 are) source.
8. 8. The circuit protection circuit according to claim 1, wherein said short circuit protection circuit further comprises a load when the switching circuit is opened tube M0S said load circuit, said load circuit for turning on the recovery from the detection circuit (4), said self-recovery detecting circuit (4) comprises a third voltage dividing resistor (R39) and a fourth voltage dividing resistor (R40), said third voltage dividing resistor (R39) and the first quarter resistor (R40) connected to a connection node of the cathode of the battery, the other terminal of the third voltage dividing resistor (R39) is connected to the positive electrode of the battery, the fourth voltage dividing resistor (R40) of the other end, the third voltage dividing resistor (R39) is connected to a second input of the microcontroller and the fourth voltage dividing resistor (R40) is connected to the node.
9. 9. The circuit protection circuit according to claim 1, wherein said circuit protection circuit further includes a transient suppression circuit high voltage, the transient high voltage transient suppression circuit includes an input and an output high voltage transient suppression circuit high voltage suppression circuit, the input transient suppression circuit includes a high voltage regulator input capacitance (the C28), the output high voltage transient suppression circuit includes a second diode (D2) and an output stabilization capacitor (-C29), the input stabilizing capacitance (the C28) is connected between the positive and negative electrodes of the battery, the second diode (D2) is a cathode connected to the anode of the load circuit, the second diode (D2) of an anode connected to the cathode of the load circuit, the output stabilizing capacitance (-C29) in parallel with the load circuit.
10. 10. The circuit protection circuit according to claim 9, wherein said input transient suppression circuit further includes a high voltage is connected between the positive and negative electrodes of the battery of the TVS diode, a varistor or a thermistor .