CN102996885B - 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
CN102996885B
CN102996885B CN201210399297.4A CN201210399297A CN102996885B CN 102996885 B CN102996885 B CN 102996885B CN 201210399297 A CN201210399297 A CN 201210399297A CN 102996885 B CN102996885 B CN 102996885B
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China
Prior art keywords
connected
diode
circuit
resistance
drive circuit
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CN201210399297.4A
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Chinese (zh)
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CN102996885A (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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Publication of CN102996885A publication Critical patent/CN102996885A/en
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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 120mA left and right.Electromagnetic priority valve and electromagnetic valve driver are two independently products, connect between the two with flexible cable.Because underground work environment is severe, coal ash is many, and aqueous vapor is large, often because flexible cable damages, makes the output of electromagnetic valve driver drive interface inner product to have foreign material, and between contact pin, insulating properties reduces, and often burns out inner driving pipe.For this reason, need to design a protective circuit and protect driver.

Conventional protecting circuit designed thinking has several as follows: a shared protective circuit of a plurality of driving pipes of (1) design; reduce cost and pcb board occupation area; this just requires the protective current threshold values of protective circuit larger; the electric current sum that drives pipe simultaneously to work required to adapt to multichannel; again because protective current threshold values is higher; necessity asks each to drive pipe to have larger electric current ability to bear, and this certainly will increase cost and the volume that drives pipe.And one drives pipe to cause protection because of damage, and other drives pipe normally to export normally.(2) adopt overcurrent current constant mode, when output drives mouth short circuit, make to drive the current constant that passes through of pipe; although this method can play a protective role; but it has consumed energy, the temperature 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 complete the overcurrent protection that drives pipe, but price is higher again.

Summary of the invention

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

The present invention solves the problems of the technologies described above adopted technological scheme: 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, 12V power supply is connected with drive circuit, signal input part is connected with drive circuit, signal input part is connected with 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, 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, between the grid of described field effect transistor and source electrode, be provided with the second resistance, 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 12V power supply, the negative pole of the first diode is connected with one 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, between signal input part and the base stage of triode, be provided with the 5th resistance, the base stage of triode is connected with the positive pole of the 3rd diode, the 3rd negative pole of diode and the other end of loading coil are connected, 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, the negative pole of the second diode passes through capacity earth.

Compared with prior art, advantage of the present invention is that control signal is inputted the control signal of Transistor-Transistor Logic level from P2 port, by drive circuit, removes to drive loading coil.When loading coil breaks down short circuit; by load detecting circuit, detected; after protective circuit is processed, controlling drive circuit disconnects; 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.

Accompanying drawing explanation

Fig. 1 is structured flowchart of the present invention;

Fig. 2 is circuit diagram of the present invention.

Embodiment

Below in conjunction with accompanying drawing, embodiment is described in further detail the present invention.

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, between the grid of field effect transistor Q1 and source electrode, be provided with the second resistance R 2, 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 one 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, between the base stage of signal input part P2 and triode Q2, be provided with the 5th resistance R 5, 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, 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 severe because of Environmental Conditions is often short-circuited between output P4, P5.The object of this circuit is exactly: when P4, P5 short circuit, and protection driving tube Q1.

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, form the cmos switch type drive circuit that general low side is controlled, when P2 end input TTL high level, 5V voltage is through the first resistance R 1, the second resistance R 2 dividing potential drops, between grid-source electrode of being on the scene effect pipe Q1, form the control voltage of 4.2V, field effect transistor Q1 therefore and conducting, thereby drive electromagnetic coil.When field effect transistor Q1 disconnects, the high back voltage on loading coil directs on 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.

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

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 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 from cut-off, and the pressure drop in 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 cut-in voltage, field effect transistor Q1 cut-off, thus protected driving tube Q1.

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

Claims (1)

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, 12V power supply is connected with drive circuit, signal input part is connected with drive circuit, signal input part is connected with 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, 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, the first described 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, between the grid of described field effect transistor and source electrode, be provided with the second resistance, 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 12V power supply, the negative pole of the first diode is connected with one 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, between signal input part and the base stage of triode, be provided with the 5th resistance, the base stage of triode is connected with the positive pole of the 3rd diode, the 3rd negative pole of diode and the other end of loading coil are connected, 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, 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
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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 CN102996885A (en) 2013-03-27
CN102996885B true CN102996885B (en) 2014-10-08

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Citations (7)

* 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
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

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000287355A (en) * 1999-03-30 2000-10-13 Nec Eng Ltd Short-circuit protective system

Patent Citations (7)

* 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
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

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
JP特开2000-287355A 2000.10.13

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