CN102996885A - Protection drive circuit of small-power electromagnetic coil - Google Patents

Protection drive circuit of small-power electromagnetic coil Download PDF

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Publication number
CN102996885A
CN102996885A CN2012103992974A CN201210399297A CN102996885A CN 102996885 A CN102996885 A CN 102996885A CN 2012103992974 A CN2012103992974 A CN 2012103992974A CN 201210399297 A CN201210399297 A CN 201210399297A CN 102996885 A CN102996885 A CN 102996885A
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CN
China
Prior art keywords
connected
diode
circuit
drive circuit
resistance
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CN2012103992974A
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Chinese (zh)
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CN102996885B (en
Inventor
应永华
姚志生
宋磊
蔡伟胜
沈小龙
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宁波长壁流体动力科技有限公司
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Priority to CN201210399297.4A priority Critical patent/CN102996885B/en
Publication of CN102996885A publication Critical patent/CN102996885A/en
Application granted granted Critical
Publication of CN102996885B publication Critical patent/CN102996885B/en

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Abstract

The invention discloses a protection drive circuit of a small-power electromagnetic coil. The protection drive circuit comprises a drive circuit, a starting control circuit, a protection circuit and a load detection circuit, wherein a 12V power supply is connected with the drive circuit, a signal input end is connected with the drive circuit and the starting control circuit, the drive circuit is connected with the protection circuit, the starting control circuit is connected with the protection circuit, the drive circuit is connected with a load coil, and the load detection circuit is connected with the load coil and the protection circuit. The protection drive circuit of the small-power electromagnetic coil has the advantages that a control signal of a TTL level is input from a P2 port, and the drive circuit drives the load coil; and when the load coil has a fault and is in short circuit, the fault is detected by the load detection circuit, the drive circuit is controlled to be disconnected after the fault is processed by the protection circuit, and thus the drive circuit is protected. A drive tube with low cost and low power consumption can be selected for driving the load coil, so that the design cost of the circuit is reduced, and the power consumption is low.

Description

A kind of protection drive circuit of small power electric magnetic coil

Technical field

The present invention relates to a kind of protective circuit, especially relate to a kind of protection drive circuit of small power electric magnetic coil.

Background technique

In coal mine fully-mechanized mining working hydraulic support electrohydraulic control system product, the driver (abbreviation electromagnetic valve driver) that needs electromagnetic priority valve, an electromagnetic valve driver will drive ten multi-disc electromagnetic priority valves, and the rated operational voltage of electromagnetic priority valve is 12VDC, and operating current is about 120mA.Electromagnetic priority valve and electromagnetic valve driver are two independently products, connect with flexible cable between the two.Because the underground work environment is abominable, coal ash is many, and aqueous vapor is large, often because flexible cable damages the output driving interface inner product that makes electromagnetic valve driver foreign material is arranged, and insulating properties reduces between contact pin, often burns out inner driving pipe.For this reason, need protective circuit of design to protect driver.

Protecting circuit designed thinking commonly used has following several: the protective circuit that a plurality of driving pipes of (1) design share; come Cost reduction and pcb board occupation area; this just requires the protective current threshold values of protective circuit larger; drive the electric current sum that pipe is worked required simultaneously to adapt to multichannel; higher because of the protective current threshold values again; necessity asks each to drive pipe larger electric current ability to bear, and this certainly will increase cost and the volume that drives pipe.And a driving pipe causes protection because of damage, and other drives normally pipe and can not normally export.(2) adopt the overcurrent current constant mode, when output drives the mouth short circuit, make the current constant that passes through that drives pipe; although this method can play a protective role; but it has consumed energy, and the temperature the when consumption of energy also causes product bug raises, and has strengthened the design difficulty of product heat radiation.(3) adopt specific integrated circuit to finish the overcurrent protection that drives pipe, but price is higher again.

Summary of the invention

Technical problem to be solved by this invention provides the small-power protection drive circuit that a kind of cost is lower, energy consumption is little, is used for the driving to the small power electric magnetic coil, and it adopts the overcurrent turn-off function mode, and the employing resolution element is realized the overcurrent protection to the coil drive pipe.

The present invention solves the problems of the technologies described above the technological scheme that adopts: a kind of protection drive circuit of small power electric magnetic coil; it is characterized in that comprising drive circuit; start control circuit; protective circuit and load detecting circuit; the 12V power supply is connected with drive circuit; signal input part is connected with drive circuit; signal input part is connected with the startup control circuit; described drive circuit is connected with described protective circuit; described startup control circuit is connected with described protective circuit; described drive circuit is connected with loading coil; described load detecting circuit is connected with described loading coil, and described load detecting circuit is connected with described protective circuit.

Described drive circuit comprises the first resistance, the second resistance, field effect transistor, the 3rd resistance and the first diode; described protective circuit comprises the 5th resistance, triode, described the first resistance and the 4th diode; described startup control circuit comprises the 4th resistance, electric capacity, the second diode and the 5th diode; described load detecting circuit comprises the 3rd resistance and the 3rd diode

Described signal input part is connected with the grid of field effect transistor by the first resistance, be provided with the second resistance between the grid of described field effect transistor and the source electrode, the drain electrode of field effect transistor is connected with the positive pole of the first diode by the 3rd resistance, the negative pole of the first diode is connected with the 12V power supply, the negative pole of the first diode is connected with an end of loading coil, the positive pole of the first diode is connected with the other end of loading coil, the source ground of field effect transistor

The collector electrode of triode is connected with the grid of field effect transistor, the emitter of triode is connected with the positive pole of the 4th diode, the minus earth of the 4th diode, be provided with the 5th resistance between the base stage of signal input part and triode, the base stage of triode is connected with the positive pole of the 3rd diode, the negative pole of the 3rd diode is connected with the other end of loading coil, signal input part is connected with the negative pole of the 5th diode, the positive pole of the 5th diode is connected with the negative pole of the second diode, the positive pole of the second diode is connected with the base stage of triode, signal input part is connected with the negative pole of the second diode by the 4th resistance, and the negative pole of the second diode passes through capacity earth.

Compared with prior art, advantage of the present invention is control signal is inputted Transistor-Transistor Logic level from the P2 port control signal, removes to drive loading coil by drive circuit.When loading coil breaks down short circuit; detected by load detecting circuit; the control drive circuit disconnects after protective circuit is processed; thereby protected drive circuit; can select the driving tube of lower cost and lower power consumption to drive loading coil; reduced the design cost of circuit, power dissipation ratio is lower simultaneously.

Description of drawings

Fig. 1 is structured flowchart of the present invention;

Fig. 2 is circuit diagram of the present invention.

Embodiment

Embodiment is described in further detail the present invention below in conjunction with accompanying drawing.

A kind of protection drive circuit of small power electric magnetic coil; comprise drive circuit 1, start control circuit 2, protective circuit 3 and load detecting circuit 4; 12V power supply P1 is connected with drive circuit 1; signal input part P2 is connected with drive circuit; signal input part P2 is connected with startup control circuit 2; drive circuit 1 is connected with protective circuit 3; starting control circuit 2 is connected with protective circuit 3; drive circuit 1 is connected with loading coil RL; load detecting circuit 4 is connected with loading coil RL, and load detecting circuit 4 is connected with protective circuit 3.

Drive circuit 1 comprises the first resistance R 1, the second resistance R 2, field effect transistor Q1, the 3rd resistance R 3 and the first diode D1; protective circuit 3 comprises the 5th resistance R 5, triode Q2, the first resistance R 1 and the 4th diode D4; start control circuit 2 and comprise the 4th resistance R 4, capacitor C 1, the second diode D2 and the 5th diode D5; load detecting circuit 4 comprises the 3rd resistance R 3 and the 3rd diode D3

Signal input part P2 is connected with the grid of field effect transistor Q1 by the first resistance R 1, be provided with the second resistance R 2 between the grid of field effect transistor Q1 and the source electrode, the drain electrode of field effect transistor Q1 is connected with the positive pole of the first diode D1 by the 3rd resistance R 3, the negative pole of the first diode D1 is connected with 12V power supply P1, the negative pole of the first diode D1 is connected with the end of loading coil RL, the positive pole of the first diode D1 is connected with the other end of loading coil RL, the source ground P3 of field effect transistor Q1

The collector electrode of triode Q2 is connected with the grid of field effect transistor Q1, the emitter of triode Q2 is connected with the positive pole of the 4th diode D4, the minus earth of the 4th diode D4, be provided with the 5th resistance R 5 between the base stage of signal input part P2 and triode Q2, the base stage of triode Q2 is connected with the positive pole of the 3rd diode D3, the negative pole of the 3rd diode D3 is connected with the other end of loading coil RL, signal input part is connected with the negative pole of the 5th diode D5, the positive pole of the 5th diode D5 is connected with the negative pole of the second diode D2, the positive pole of the second diode D2 is connected with the base stage of triode Q2, signal input part P2 is connected with the negative pole of the second diode D2 by the 4th resistance R 4, and the negative pole of the second diode D2 is by capacitor C 1 ground connection.

Working principle of the present invention: signal input part is pin P1(12V), P2(TTL), P3 (GND), output terminal is P4 (12V), P5.Output terminal connects electromagnetic coil outward, and the dc resistance of loading coil is about 100 Ω, and abominable because of Environmental Conditions often is short-circuited between output P4, the P5.The purpose of this circuit is exactly: when P4, P5 short circuit, and protection driving tube Q1.

The cmos switch type drive circuit that is formed general low side control by element the first resistance R 1, the second resistance R 2, field effect transistor Q1, the 3rd resistance R 3, the first diode D1 and loading coil RL, when P2 end input TTL high level, 5V voltage is through the first resistance R 1, the second resistance R 2 dividing potential drops, form the control voltage of 4.2V between grid-source electrode of being on the scene effect pipe Q1, field effect transistor Q1 therefore and conducting, thereby drive electromagnetic coil.When field effect transistor Q1 disconnected, the high back voltage on the loading coil directed on the power line through the first diode D1, thus protection field effect transistor Q1.The second resistance R 2 plays dividing potential drop effect and the effect of releasing of grid parasitic capacitance at this.

Form protective circuit by element the 5th resistance R 5, triode Q2, the first resistance R 1, the 4th diode D4, it controls the grid G of driving tube Q1.Form load detecting circuit by the 3rd resistance R 3, the 3rd triode D3.Form the startup control circuit by the 4th resistance R 4, capacitor C 1, the second diode D2, the 5th diode D5.

When the second diode D2, the 3rd not conducting of diode D3, regulate the value of the 5th resistance R 5, the first resistance R 1, make triode Q2 be operated in undersaturated condition, allow the collector electrode C voltage of triode Q2 be lower than the grid G cut-in voltage of field effect transistor Q1.The 4th diode D4 is the electrical level match diode with the 3rd diode D3, the second diode D2, when driven is worked, the drain D voltage of field effect transistor Q1 is lower, the 3rd diode D3 conducting, because the 4th diode D4 raises the voltage of the emitter E of triode Q2, triode Q2 cut-off, driving tube Q1 is normally still.

When output terminal P4, P5 short circuit, flow through the Current rise of the 3rd resistance R 3, pressure drop on it increases, cause the 3rd diode D3 shunting little, triode Q2 becomes magnifying state by cut-off, and the pressure drop on the first resistance R 1 increases, the grid G lower voltage of field effect transistor Q1, the drain-source electrode resistance of field effect transistor Q1 increases, and further makes the shunting of the 3rd diode D3 less.Positive feedback effect is until the 3rd diode D3 ends, and triode Q2 enters undersaturated condition, and the grid voltage of field effect transistor Q1 drops under the cut-in voltage, field effect transistor Q1 cut-off, thus protected driving tube Q1.

The P2 input end is low level before adding the TTL high level, field effect transistor Q1 cut-off, the 3rd diode D3 ends, in the moment that the P2 high level adds, a path is provided, and the base current of shunting triode Q2 makes triode Q2 be in cut-off state, allow driving tube Q1 normally, drive external coil.The 4th resistance R 4, capacitor C 1, the second diode D2 finish this function exactly, powering on beginning, because capacitor C 1 both end voltage can not be suddenlyd change, voltage is from 0 rising on it, and the second diode D2 conducting is shunted, make triode Q2 be in cut-off state, after field effect transistor Q1 conducting, the 3rd diode D3 continues then to finish the shunting of triode Q2 base stage, and this moment, capacitor C 1 both end voltage was higher, its startup effect is finished in the second diode D2 cut-off.Regulate the value of the 4th resistance R 4, capacitor C 1, the control opening time is approximately greater than the conducting delay time of field effect transistor Q1.This time can not be excessive, selects less driving pipe of opening time as far as possible, and general small-power CMOS pipe all can the Full foot.The effect of the 5th diode D5 is during for the control signal step-down, bleeds off rapidly the electric charge on the capacitor C 1, prepares for the unlatching control of next time, can improve control rate.

Claims (2)

1. the protection drive circuit of a small power electric magnetic coil; it is characterized in that comprising drive circuit; start control circuit; protective circuit and load detecting circuit; the 12V power supply is connected with drive circuit; signal input part is connected with drive circuit; signal input part is connected with the startup control circuit; described drive circuit is connected with described protective circuit; described startup control circuit is connected with described protective circuit; described drive circuit is connected with loading coil; described load detecting circuit is connected with described loading coil, and described load detecting circuit is connected with described protective circuit.
2. the protection drive circuit of a kind of small power electric magnetic coil according to claim 1; it is characterized in that described drive circuit comprises the first resistance; the second resistance; field effect transistor; the 3rd resistance and the first diode; described protective circuit comprises the 5th resistance; triode; described the first resistance and the 4th diode; described startup control circuit comprises the 4th resistance; electric capacity; the second diode and the 5th diode; described load detecting circuit comprises the 3rd resistance and the 3rd diode
Described signal input part is connected with the grid of field effect transistor by the first resistance, be provided with the second resistance between the grid of described field effect transistor and the source electrode, the drain electrode of field effect transistor is connected with the positive pole of the first diode by the 3rd resistance, the negative pole of the first diode is connected with the 12V power supply, the negative pole of the first diode is connected with an end of loading coil, the positive pole of the first diode is connected with the other end of loading coil, the source ground of field effect transistor
The collector electrode of triode is connected with the grid of field effect transistor, the emitter of triode is connected with the positive pole of the 4th diode, the minus earth of the 4th diode, be provided with the 5th resistance between the base stage of signal input part and triode, the base stage of triode is connected with the positive pole of the 3rd diode, the negative pole of the 3rd diode is connected with the other end of loading coil, signal input part is connected with the negative pole of the 5th diode, the positive pole of the 5th diode is connected with the negative pole of the second diode, the positive pole of the second diode is connected with the base stage of triode, signal input part is connected with the negative pole of the second diode by the 4th resistance, and the negative pole of the second diode passes through capacity earth.
CN201210399297.4A 2012-10-19 2012-10-19 Protection drive circuit of small-power electromagnetic coil CN102996885B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201210399297.4A CN102996885B (en) 2012-10-19 2012-10-19 Protection drive circuit of small-power electromagnetic coil

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Application Number Priority Date Filing Date Title
CN201210399297.4A CN102996885B (en) 2012-10-19 2012-10-19 Protection drive circuit of small-power electromagnetic coil

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CN102996885A true CN102996885A (en) 2013-03-27
CN102996885B CN102996885B (en) 2014-10-08

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Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5986442A (en) * 1997-10-27 1999-11-16 Keihin Corporation Load drive device having short-circuit protection function
JP2000287355A (en) * 1999-03-30 2000-10-13 Nec Eng Ltd Short-circuit protective system
CN101557091A (en) * 2008-04-09 2009-10-14 株式会社东海理化电机制作所 Short circuit protection circuit
CN101944715A (en) * 2010-08-31 2011-01-12 深圳拓邦股份有限公司 Load short-circuit protection circuit
CN202261119U (en) * 2011-10-28 2012-05-30 南通富士通微电子股份有限公司 Driving integrated circuit of bidirectional direct-current (DC) motor
CN102612209A (en) * 2012-01-20 2012-07-25 中国科学院上海技术物理研究所 Recoverable protective circuit of boosting LED (light emitting diode) driving power supply and design method of recoverable protective circuit
CN102723693A (en) * 2012-05-31 2012-10-10 南京德朔实业有限公司 Load protection circuit and method for electric tool
CN202852128U (en) * 2012-10-19 2013-04-03 宁波长壁流体动力科技有限公司 Protection and drive circuit of low-power electromagnetic coil

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5986442A (en) * 1997-10-27 1999-11-16 Keihin Corporation Load drive device having short-circuit protection function
JP2000287355A (en) * 1999-03-30 2000-10-13 Nec Eng Ltd Short-circuit protective system
CN101557091A (en) * 2008-04-09 2009-10-14 株式会社东海理化电机制作所 Short circuit protection circuit
CN101944715A (en) * 2010-08-31 2011-01-12 深圳拓邦股份有限公司 Load short-circuit protection circuit
CN202261119U (en) * 2011-10-28 2012-05-30 南通富士通微电子股份有限公司 Driving integrated circuit of bidirectional direct-current (DC) motor
CN102612209A (en) * 2012-01-20 2012-07-25 中国科学院上海技术物理研究所 Recoverable protective circuit of boosting LED (light emitting diode) driving power supply and design method of recoverable protective circuit
CN102723693A (en) * 2012-05-31 2012-10-10 南京德朔实业有限公司 Load protection circuit and method for electric tool
CN202852128U (en) * 2012-10-19 2013-04-03 宁波长壁流体动力科技有限公司 Protection and drive circuit of low-power electromagnetic coil

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