CN1037809A

CN1037809A - The driving switch circuit

Info

Publication number: CN1037809A
Application number: CN88102740A
Authority: CN
Inventors: 施木贵
Original assignee: Individual
Current assignee: Individual
Priority date: 1988-05-20
Filing date: 1988-05-20
Publication date: 1989-12-06
Also published as: CN1018129B

Abstract

The invention discloses a kind of novel driving switch circuit, it utilizes reaction type cut-off type current protection technology and switching regulator constant-current type biasing technique, therefore can realize overcurrent protection under less power consumption situation, and circuit shutoff quiescent dissipation is zero.Circuit can not damage under misconnection electric power polarity situation, and can automatically reset after the output overloading fault is got rid of.Realize that the present invention has two kinds of Starting mode, a kind of is to utilize electric capacity charging generation pulse is realized starting, and another kind is to utilize the pulse of triode feedback generation to realize starting.The present invention can be widely used in all kinds of sensitive switches and the automatic control system.

Description

The driving switch circuit

The present invention is a kind of novel driving switch circuit, can make speed-sensitive switch and use in various control system.

Many driving switch circuit often only consider how to drive load, and protective device is not set.External TWH8751 and TWH8778 driving switch integrated circuit etc., though be provided with protective circuit, the flow pattern mode that subtracts has been adopted in their overcurrent protection, thus circuit power consumption is very big, and this is not suitable for the technology of domestic present production integrated circuit.For example, 8751 circuit output ends adopt open-collector Darlington transistor, export maximum current 2A, can bear the voltage of 100V, and control switch power reaches 50W.When output current during greater than 2A, subtracting the flow pattern protective circuit can shunt efferent duct, and output current is reduced to about 1A automatically.In addition, sort circuit has certain shutoff quiescent dissipation.Sort circuit is easy to damage circuit when output overloading and misconnection electric power polarity.

The objective of the invention is in order to overcome the shortcoming of foregoing circuit, by brand-new design, it is almost nil to obtain a kind of shutoff quiescent dissipation, and output overloading and misconnection electric power polarity can not damage, and can automatically reset driving switch.

Principle of the present invention is to utilize reaction type cut-off type current protection technology and switching regulator constant-current type biasing technique; therefore circuit can be under less power consumption situation; realize overcurrent protection; this circuit is under the operating voltage situation of different brackets; output current is consistent, and circuit shutoff quiescent dissipation is zero.In circuit, be provided with polarity protection and automatic reset device, circuit can not damaged under misconnection electric power polarity situation, and can after the output overloading fault is got rid of, automatically reset.

Fig. 1 is a functional-block diagram of the present invention.

As seen from Figure 1, circuit is made up of input stage, start-up circuit, output driving circuit, feedback protection circuit, overvoltage protection, polar protective circuit etc.When being input as 1 level, input stage (1) is ended, and start-up circuit (2) is in off-state, and output driving circuit (3) is in cut-off state, and output is the O level.When being input as the O level, input stage (1) conducting, start-up circuit (2) produces a pulse, makes output driving circuit (3) by saturated by entering, and output is 1 level.After output driving circuit (3) is saturated, make feedback protection circuit (4) enter conducting, make start-up circuit (2) after producing pulse, still keep conducting after feedback protection circuit (4) conducting, make output driving circuit (3) keep stable output.When output overloading; output potential reduces; cause feedback protection circuit (4) to end; the path of start-up circuit (2) disconnects; output driving circuit (3) ends; output is the O level, thereby circuit can not damage when making output overloading, and the overvoltage protection (5) of output driving circuit (3) makes the unlikely permissible value that exceeds of the voltage that is added on the output driving circuit (3).Polar protective circuit (6) makes and under misconnection electric power polarity situation circuit can not damaged.Automatic reset circuit (7) can automatically reset after the output overloading fault is got rid of.

Realize that the present invention has two kinds of Starting mode, a kind of is to utilize electric capacity charging generation pulse is realized starting, and another kind is that the pulse that utilizes triode to lock generation realizes starting.Set forth respectively below.

Fig. 2 is for adopting the electrical schematic diagram of electric capacity charge initiation.

Among Fig. 2, when planting for high level, triode BG ₁, BG ₂End, thus triode BG ₃, BG ₄End triode BG ₅, BG ₆Also must end, this moment, output was a low level.When input adds low level, input stage BG ₁Conducting, collector current IC ₁Through diode D ₁, D ₂, D ₃Clamper is given start-up circuit BG ₂, BG ₂Conducting, electric current I _E2Through resistance R ₄And capacitor C ₁To starting capacitor C ₂Charging, BG ₂Collector electrode is enough to make BG by the negative pulse that produces by the end of conducting ₃By by entering conducting, export driving tube BG ₃Conducting, output is a high level, and makes feedback protection circuit BG ₅, BG ₆Conducting, BG ₆I is given in conducting _E2Provide path, simultaneously to capacitor C ₂Discharge.I _E2Normally makes BG ₃Kept stable output.When exporting when cutting, the output current potential descends, and causes BG ₅End BG ₆End I _E2Reduce, make BG at once ₃Change over to very soon and end, output is a low level, thereby circuit is not damaged because of output overloading.Automatic reset electro route R ₉, R ₁₀, D ₉Deng composition.Work as output overloading, output is a low level, diode D ₈Negative pole is near zero potential, and A point current potential approximates diode D ₉0.7 volt of pressure drop own is through R ₁₀, R ₈Dividing potential drop, BG ₆Base voltage is lower than 0.7 volt, BG ₆Be in and cut the rising of the faint-hearted  Xi of coffin thorn 5 Sus the upper and lower teeth not meeting properly  felicity Cheng point current potential, BG ₆Conducting, BG ₃Conducting, BG ₅Conducting, BG ₆Enter saturatedly by conducting, make BG ₃Keep stable output, thereby realized output overloading or short trouble eliminating back auto-reset function.BG ₄Be BG ₅The biased witch pipe adopts this mode, has realized that it is zero that circuit turn-offs quiescent dissipation.D ₄, D ₅, D ₆Be clamp diode, diode D ₇Be to prevent BG ₅Reverse-conducting, D ₈Be polarity protection diode, D _W1Be BG ₃The overvoltage protection voltage-stabiliser tube, BG ₇BG ₈Be the clamper triode.

Fig. 3 is the electrical schematic diagram that adopts the triode feedback to start.

Among Fig. 3, when input is high level, triode BG ₁-BG ₈All be in cut-off state, output is a low level.When input adds low level, input stage BG ₁Conducting, I _E1Through D ₁, D ₂, D ₃Clamper is given start-up circuit BG ₂Set up bias voltage, BG ₂Conducting, BG ₄Conducting, BG ₄Feedback protection circuit BG is given in conducting ₆With feedback circuit BG ₇Bias switching circuit pipe BG ₅Open passage, BG ₅Conducting, I _E5Through D ₆, D ₇, D ₈Clamper is given BG ₆, BG ₇Set up bias voltage, BG ₇Conducting, BG ₈Conducting, I _R5By bypass.In this converse lock process, output driving circuit BG ₃By saturated by entering, output is a high level, and makes inverse-locking protection circuit BG ₆Conducting, BG ₆Give BG after the conducting ₄Set up new bias voltage.At this moment BG ₈Conducting is to I _R5Bypass has not influenced BG ₄Stablize conducting, BG ₃Kept stable output.When output overloading, the output current potential descends, and causes BG ₆End BG ₄Losing setovers to change over to ends, and makes BG ₃End, output is a low level, so output overloading can not damage circuit yet at once.Diode D in the circuit ₅After ending, by diode D ₁₁Connect I _E5The loop makes BG ₅, BG ₇, BG ₈Still keep conducting.Other operation principle is similar to Fig. 2 circuit.

The present invention can be widely used in solid state relay, near switch, optoelectronic switch, hall switch, in sensitive switch such as magnetosensitive switch and the automatic control system.Owing to be provided with protective circuit in the circuit; therefore the output in above-mentioned switch and the automatic control system drives and adopts this circuit engineering; just can not damage, and can automatically reset, give like this and produce debugging and use has brought convenience because of output overloading or wrong electric power polarity.

The present invention designs and is fit to make integrated circuit and thick film circuit.

Claims

1; a kind of driving switch circuit; it is characterized in that it is by input stage [1]; start-up circuit [2]; output driving circuit [3]; feedback protection circuit [4]; overvoltage protection [5] and polar protective circuit compositions such as [6]; when being input as the O level; input stage [1] conducting; start-up circuit [2] produces a pulse; drive circuit [3] enters saturated; be output as 1 level; feedback protection circuit [4] conducting simultaneously; make start-up circuit [2] after producing pulse, still keep conducting; make output driving circuit keep stable output; when output overloading; feedback protection circuit [4] ends, start-up circuit [2]; output driving circuit [3] ends, and is output as the O level; thereby circuit can not lose when making output overloading; overvoltage protection [5] makes the voltage that is added in output driving circuit [3] point not exceed permissible value, and polar protective circuit [6] makes that circuit can not damage when the misconnection electric power polarity, and automatic reset circuit [7] can automatically reset after the output overloading fault is got rid of.

2,, it is characterized in that start-up circuit adopts the electric capacity charging to produce pulse and realizes starting by the described driving switch circuit of claim 1.

3,, it is characterized in that start-up circuit adopts the pulse of triode feedback generation to realize starting by the described driving switch circuit of claim 1.