CN101247119A

CN101247119A - Daylight controlled switch circuit

Info

Publication number: CN101247119A
Application number: CNA2007100567712A
Authority: CN
Inventors: 成爱林
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-02-12
Filing date: 2007-02-12
Publication date: 2008-08-20

Abstract

A sunlight-controlling switching circuit comprises a photo-electric converting circuit, a composite tube amplifying emitter output circuit and an emitter coupling bistable circuit. In the circuit the emitter coupling element of the emitter coupling bistable circuit adopts a voltage stabilizing tube. The invention settles the problem of ''critical flickering'' caused by the enlarged feedback effect of the current, reduced current amplifying multiple, difficult rolling-over and extraordinary slow variation of sunlight when the emitter coupling element adopts the common-used resistor. Therefore the light-controlling sensitiveness can be increased furthest, the light-controlling sensitiveness can up to <0.2lux and is suitable for the requirement of the switching circuit of the sunlight-controlling circuit. The photosensitive element is installed indoor and can still satisfy that the ''critical flickering'' is not generated when the light is switched on and off with the necessary illumination.

Description

A kind of daylight controlled switch circuit

One, technical field

The present invention relates to a kind of light-controlled switching circuit, specifically relate to a kind of daylight controlled switch circuit that is used for controlling street lamp.

Two, technical background

At present, main adopt " time-controlled type " of street lamp control both domestic and external.Its shortcoming is a lot, and it relates to longitude and latitude, season, weather, the deviation when walking etc.Particularly weather can't be estimated, may open and close in anomalous weather lamp too early or late excessively; If " when walking " is out of order and misplaces, even may cause and turn on light in hundred days, turn off the light evening, need do " seasonal adjustment " and " rate correction ".With the science of " day photocontrol " method, accurate, energy-conservation, hommization, it does not relate to other any factors, only depends on the daylight change information, depends on the brightness of daylight in the morning of switch lamp, evening., present known various light-controlled switching circuits, all not competent control to street lamp.The analysis of causes is as follows:

Known light-controlled switching circuit mainly contains two kinds, a kind ofly is made up of 555 chips, and another kind is made up of light-operated chip of JEC-2 or Schmidt circuit.They are used for light, electric pulse generator, are very handy with the pulsed optical signals source.Yet, make the light-controlled switching circuit of street lamp with day light signal, but problem is very big, and is not competent.As, are " return difference is too big " with the problem the most significant, that can't overcome of 555 light-controlled switching circuits of forming, because being upper and lower threshold voltages, the characteristics of 555 chips differ 1/3 times of supply voltage, cause the early morning sky very brightly just to turn off the light, do not turn off the light in the cloudy day; Also have some problems with JEC-2 or Schmidt circuit, subject matter is, even light-sensitive element is installed in the open, its light-operated sensitivity (minimum value that refers to controlled illumination range) does not reach requirement yet, it is too bright when causing the open and close lamp, promptly turns on light too early, turns off the light evening.No small in addition " return difference " may not turn off the light in the cloudy day.

Strengthen that resistance is regulated in light-operated sensitivity and emitter-base bandgap grading coupling bistable resistance value all can improve light-operated sensitivity, but all be very restricted.This be because, the increasing of emitter-base bandgap grading coupling resistance strengthens its Current Negative Three-Point Capacitance effect, the current amplification factor of emitter-base bandgap grading coupling flip-flop circuit reduces, and is difficult to make the circuit upset more.And the variation of daylight is very slow, so " facing the flicker that is situated between " phenomenon occurs.In addition, light-operated sensitivity is regulated resistance value and is strengthened, and will the equivalent internal resistance of its light, power conversion circuit be strengthened, because the resistance of light-sensitive element can reach tens to the hundreds of megaohm, its load capacity is very weak, and electric current enough, that can make the circuit upset can not be provided.Along with the increase of its resistance value, " facing the flicker that is situated between " phenomenon can appear, so that out of control, can not overturn.

Three, summary of the invention and execution mode

The purpose of this invention is to provide a kind of daylight controlled switch circuit, the sensitivity of its light-operated switch is very high, and reversal rate is very fast, can be used as a day light-operated road lamp switch circuit, even light-sensitive element places indoor, also can satisfy required darkness open and close lamp, and not have " facing be situated between flicker ".

Light-operated open and close circuit will be illustrated in conjunction with the accompanying drawings in of the present invention day.

In the known light-controlled switching circuit of Fig. 1, comprise light, power conversion circuit 1, amplifying circuit 2, Schmidt circuit 3.

In the daylight controlled switch circuit of the described invention of Fig. 2, comprise light, power conversion circuit 1, multiple tube amplifies, and penetrates output circuit 2, Schmidt circuit 3.

Light, power conversion circuit 1 are regulated resistance R p by light-sensitive element and light-operated sensitivity and are composed in series.

Multiple tube amplifies, and emitter output circuit 2 is by transistor T ₁, T ₂And emitter resistance R ₁Form.

Schmidt circuit 3, by transistor T ₃, T ₄And collector resistance R _A, R _B, common emitter coupling element voltage-stabiliser tube Z ₂, transistor T ₄Base stage current limiting element voltage-stabiliser tube Z ₁, transistor T ₄Collector electrode export move to the pipe Z ₃Form.

The operation principle of daylight controlled switch circuit of the present invention is described in down:

On daytime, when the daylight deficiency was enough dark, the internal resistance value of its light-sensitive element was less, and the partial pressure value U of resistance R p is regulated in itself and light-operated sensitivity _ALower, transistor T ₁, T ₂And T ₃Be in cut-off state, transistor T ₄Be in the saturation conduction state, its pressure drop is less than 0.2 volt, and the collector electrode output voltage values is near the common emitter voltage U _E, output low level after voltage-stabiliser tube Z3 step-down.At dusk, when the daylight deepening when enough dark, when the internal resistance of light-sensitive element increases to enough greatly, its dividing point current potential U _ARise to enough height, make transistor T ₁, T ₂, T ₃Conducting, transistor T ₄By.Because the emitter-base bandgap grading coupling element of Schmidt circuit is voltage-stabiliser tube Z ₂, its electric current is very steep to the characteristic curve of voltage, so transistor T ₃The electric current rate of climb very fast.Its collector voltage descends also very fast, causes transistor T ₄Base flow sharply descend and rapidly by, that is to say that the Schmidt circuit reversal rate is very fast.Transistor T ₄By after, its collector electrode output voltage approaches supply voltage, through voltage-stabiliser tube T ₃Be still high level output after the step-down.In early morning, daylight brightens, the opto-electronic conversion voltage U _AWhen becoming enough low, transistor T ₁, T ₂, T ₃By, transistor T ₄Very fast saturation conduction, circuit are realized upset rapidly.Because voltage-stabiliser tube Z ₂Steep current characteristics, its electric current descends rapidly, so upset is also very rapid.This moment transistor T ₄Collector electrode output become low level again.

The above explanation is because the emitter-base bandgap grading coupling element Z in its Schmidt circuit ₂Steep current characteristics curve, deposit the Current Negative Three-Point Capacitance effect hardly, so upset is very fast, overcome " facing be situated between flicker " problem.Thereby, its common emitter coupled voltages U _E=U _Z2Can improve, to improve light-operated sensitivity to greatest extent as far as possible.At this moment, emitter-base bandgap grading coupled voltages U _ERaising only be subjected to the restriction of output low level voltage request.And, because the emitter-base bandgap grading coupling element Z of Schmidt circuit ₂Do not deposit the Current Negative Three-Point Capacitance effect, its current amplification factor improves greatly, thereby the burden of light, power conversion circuit output current is reduced, and regulates resistance R thereby can further increase light-operated sensitivity _PResistance, light-operated sensitivity is further enhanced, its light-operated sensitivity can reach＜0.2Lux." day light-operated road lamp switch " of inventor's development had 4 years on probation, and effect is fine.

Transistor T ₃Base stage input string resistance R ₁Effect be to prevent voltage-stabiliser tube Z ₂Overcurrent.Because when late at night, it is very big that the resistance of light-sensitive element becomes, voltage U _ABecome very high, and voltage-stabiliser tube Z ₂Electric current very steep again to the characteristic curve of voltage, so R ₁Very necessary.

The light-operated sensitivity of the Twilight Switch DAe56527 of Germany is 5Lux, and its light-sensitive element must be installed in the open, is mainly used to control indoor lamp (warehouse, shop etc.), because light-operated insufficient sensitivity height is not suitable for being used for controlling street lamp.

Description of drawings

Fig. 1 represents known light-controlled switching circuit.

Fig. 2 represents the daylight controlled switch circuit of described invention.

Claims

Daylight controlled switch circuit of the present invention comprises light, power conversion circuit 1, and multiple tube amplifies emitter output circuit 2, common emitter coupling flip-flop circuit 3.It is characterized in that the emitter-base bandgap grading coupling element adopts voltage-stabiliser tube Z in the Schmidt circuit 3 ₂, voltage-stabiliser tube Z ₂Negative pole connect cascode limit E, plus earth.And in Schmidt circuit transistor T ₃Base stage crosstalk resistance R ₁, to prevent voltage-stabiliser tube Z ₂Overcurrent.

When it had solved emitter-base bandgap grading coupling element employing resistance, because its Current Negative Three-Point Capacitance effect increasing, current amplification factor reduced, and upset is difficult to, and the variation of daylight is very slow again, thereby generation " facing is situated between glimmers " problem.Thereby can improve greatly light-operated sensitivity (＜0.2lux), satisfy the requirement of day light-operated road lamp switch.Even light-sensitive element is installed in indoor, also can realizes reaching required darkness open and close lamp and do not glimmer.