JPS61220295A - Photoelectric type flash control circuit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a photoelectric blinking control circuit used in a photoelectric automatic blinker that automatically turns on and off a light source according to illuminance.

[Background technology]

This type of photoelectric blinking control circuit has a blinking operation that turns on outdoor light sources such as street lights and security lights in the evening when it gets dark, and turns them off when it gets bright in the morning. It is often used when performing automatically. The state of automatic blinking control by this conventional photoelectric blinking control circuit (hereinafter abbreviated as "flashing control circuit" in this specification) is shown in Fig. 4, which shows the relationship between the temporal change in illuminance and the automatic blinking time. This will be explained with reference to. As shown in the illuminance curve (a) in Figure 4, the illuminance gradually decreases as the day passes and evening approaches, until the illuminance LA reaches a point where natural light alone is insufficient to distinguish objects.
become. The blinking control circuit is equipped with a circuit that photoelectrically converts the illuminance using a photoconductive element such as CdS (cadmium sulfide), and the blinking is performed based on the output signal that this photoelectric conversion circuit outputs when the illuminance is LA. A control circuit automatically turns on the light source. Thereafter, the light source continues to be lit during the night, but in the morning, the illuminance increases again and reaches the illuminance LB, which is slightly higher than the illuminance LA, and the blinking control circuit changes the output of the photoelectric conversion circuit at this time. Automatically turn off the light source based on the signal. The reason why the illuminance LB at the start of turning off the light source is higher than the illuminance LA at the start of turning on the light source is as follows. If you set it to turn off immediately after the illuminance LA has been exceeded, the illuminance will be
Even if the light source is turned on in A, immediately after that, the illuminance may return to a slightly higher level due to fluctuations in the illuminance itself or due to the lighting operation of the light source itself, and in such cases the light source will turn off again. In some cases, such a blinking operation may be repeated many times when lighting starts. This repetition of continuous blinking of the light source is undesirable because it shortens the life of the light source and causes discomfort to people.

Therefore, in order to prevent the light from turning off even if the illuminance returns to its original level (in other words, unless the illuminance returns to above LB), by setting the illumination intensities LA and LB as described above, the blinking control circuit Normally, the illuminance LB is set to a value about 2 to 5 times the illuminance LA because it has a hysteresis characteristic.

However, even if the illuminance is the same, humans perceive it as brighter in the morning than in the evening, so the illuminance LB at the start of turning off is higher than the illuminance LA at the start of turning on, and in the morning, If the light source is still lit at the illumination level LA, it will look like a night light, giving a sense of strangeness to people passing by. In other words, in the conventional blinking control circuit, unnecessary lighting is performed for a certain period of time close to when the lights are turned off in the morning. Naturally, this unnecessary lighting not only gives a sense of strangeness, but also
In addition, the light sources used in street lights consume a lot of electricity and are arranged in large numbers.
This also means that extra power is being consumed.

(Purpose of the Invention) In order to solve the above-mentioned problems, the present invention eliminates unnecessary lighting during the morning hours, extends the life of the light source, saves power consumption, and provides a comfortable environment for people passing by. The purpose of the present invention is to provide a blinking control circuit that does not give a sense of discomfort.

[Disclosure of the invention]

In order to achieve the above object, the present invention provides a rechargeable blinking control circuit including a switching element that blinks a light source based on a photoelectric conversion signal corresponding to the illuminance, in which the switching element turns on and off according to the illuminance. a level detection circuit that generates an operation signal, and generates a lighting operation signal when the illuminance is lower than a first level;
The object of the present invention is to provide a photoelectric blinking control circuit, characterized in that a detection operation switching circuit is provided for switching and controlling the detection operation level of the level detection circuit so as to generate a light-off operation signal when the level is higher than the level detection level.

The present invention will be described below with reference to FIG. 1, which shows a block diagram of a blinking control circuit according to an embodiment of the present invention, and a time chart comparing the temporal changes in the output and operation of the main blocks and the temporal changes in the light source blinking operation. This will be explained with reference to FIG. 3 shown in FIG.

As the evening approaches and the illuminance decreases, the photoelectric conversion output V of the photoelectric conversion circuit 1 decreases, as shown in the output waveform (b) shown in FIG.

The output of this photoelectric conversion circuit 1 is input to each of the second level detection circuit 2 and the second level detection circuit 5a. When the photoelectric conversion output V falls below the level E1 corresponding to the first level of illuminance at time T1, the first level detection circuit 2 detects this, and as shown in FIG. , its output is inverted from L level to H level. Immediately when the output of the first level detection circuit 2 becomes H level, the switching element drive circuit 3 operates the switching element so that the light source 4 lights up.

In other words, when the output of this first level detection circuit 2 is at H level, it means that a lighting operation signal is generated, and when this output is at L level, it means that a light-off operation signal is generated. It will become. That is, this first level detection circuit 2 is one level detection circuit that generates a signal for turning on/off the switching element according to the illuminance. ,H
A hysteresis characteristic is provided such that when the level is reversed, the output does not return to the L level unless the photoelectric conversion output V reaches a level 83 or higher, which is slightly higher than the level E1.

As the illuminance further decreases, the photoelectric conversion output V reaches level E.
2, the output of the second level detection circuit 5a is inverted from L level to H level, and in response to this inversion to H level, the photoelectric conversion sensitivity control circuit 5b switches the sensitivity of the photoelectric conversion circuit 1 to a higher side. , after time T2, the photoelectric conversion output V
remains at a high level, as shown by the solid line in FIG. Once the output of the second level detection circuit 5a is inverted to H level, the photoelectric conversion output ■ becomes level E2.
It has a hysteresis characteristic that does not return to the L level unless the level reaches a higher level of 84 or higher.

If there is no sensitivity switching, the sensitivity remains at the same low level as before, as shown by the dashed line in FIG. Therefore, although the same first level detection circuit 2 is used, after the sensitivity switching described above, a level detection signal is generated in response to a lower illuminance than before the switching. As morning approaches, at time T3, the photoelectric conversion output ■ shown by the solid line in Figure 3 rises to level E3, the output of the first level detection circuit 2 returns to L level, and the light source 4 immediately turns off. do. As mentioned above, since the sensitivity of the photoelectric conversion circuit 1 is high, the illuminance at time T3 is much lower than the illuminance at time TI in the evening of the previous day. At E4, the output of the second level detection circuit 5a becomes L.
level and the sensitivity of the photoelectric conversion circuit 1 returns to its original level. In other words, the detection operation level becomes "non-switching" as shown in FIG. As can be seen from this, the detection operation level of the first level detection circuit 2 changes from time T2 to time T5.
It is only on the "switching" side during this period.

As a result of the above, as shown in FIG. 3, the light source is turned on at time T1 in the evening, and the light source is turned off the next morning at time T3, when the illuminance is lower than the illuminance at time T3.
The lighting time is shortened by the period from time T4 (period T shown in FIG. 3). Normally, the first level detection circuit 2 and the second level detection circuit 5a are adjusted and set to operate in reverse so that the illuminance when the lights are turned on is approximately 1.5 to 5 times the illuminance when the lights are turned off. ing.

Note that in this example, the illuminance after the start of lighting was detected and the sensitivity of photoelectric conversion was changed, but the sensitivity is not limited to this, for example,
After the lighting starts, a timer circuit may be provided to measure a certain period of time from the start, and the sensitivity of the photoelectric conversion may be switched based on the output signal of this timer circuit.

Next, a more detailed explanation will be given with reference to FIG. 2, which shows a circuit in which each block of the blinking control circuit shown in FIG. 1 is more concretely illustrated, and the above-mentioned FIG. 3. The photoelectric conversion circuit 1 is configured by, for example, a photoconductive element D1 such as CdS and resistors R1 and R2 connected in series. As the illuminance decreases, the photoelectric conversion output (2) decreases (details will be explained later), but the diode D2 conducts and deconducts depending on the 14-point voltage value of the output of the comparator CP2, and the resistor R2 becomes substantially A short circuit occurs, or points 74 and 75 become non-conducting, causing the resistor R2 to become substantially non-short circuited.In the short-circuit state, the impedance of the photoelectric conversion circuit l decreases, and the photoelectric conversion circuit l decreases. The conversion sensitivity becomes low, and when the photoelectric conversion circuit 1 is in a non-short circuit state, the impedance of the photoelectric conversion circuit 1 increases, and the photoelectric conversion sensitivity becomes high.
It is composed of a comparator CP1 that performs an inverting operation with reference to the voltage at point v2, which provides the photoelectric conversion level E1 at which lighting starts. Since the output of this comparator CP1 is connected to the gate of the thyristor Sl, the comparator C
When PI is inverted and its output changes from L level to H level and a lighting operation signal is generated, thyristor S1 becomes conductive, and along with this conduction, the full wave rectifier circuit D3 is transferred from resistor R9.
Since a current flows through the triac (bidirectional thyristor > 32), which is a switching element, conducts.

By conducting this tritic S2, the power supply 6
Since the current starts flowing through the light source 4, the light source 4 starts lighting. As long as the output of the comparator CPI is at H level, the thyristor S1 maintains conduction, so the light source 4
continues to light up. At the same time when the comparator CPI is inverted to the H level, the feedback resistor R7 causes the two-point voltage to change slightly compared to before the inversion to the H level, so the level El of the photoelectric conversion output V which is inverted to the L level is Changes to E3. In other words, the aforementioned hysteresis operation is realized by changing the voltages at these 72 points. On the other hand, the second level detection circuit 5a is composed of a comparator CP2 that performs an inverting operation with reference to the 73-point voltage that provides the level E2 of the photoelectric conversion output V at which the light source 4 turns off. When the photoelectric conversion output V is at level 82 or higher, the output of the comparator CP2 is at the L level (voltage close to the common line CM) such that the 5-point voltage is almost the voltage of the common line CM, so The upper resistor R2 becomes short-circuited. Therefore, in this state, the photoelectric conversion circuit 1 is constituted by the photoconductive element D1 and the resistor R2 connected in series. However, at time T2, level E
2 or less, the output of comparator CP2 becomes H.
level, the voltage at point 74 becomes higher than the voltage at point 5, and diode D2 becomes non-conductive, so practically resistance R2
becomes a non-short circuit state. Therefore, in this state, the photoelectric conversion circuit 1 is composed of the photoconductive element D1 and the resistors R1 and R2 connected in series, and the photoelectric conversion sensitivity becomes high. Even with illuminance, the photoelectric conversion output V changes along the upper solid line. Note that at the same time that the output of the comparator CP2 is inverted to H level, the voltage at point 73 changes slightly due to the feedback resistor R8, so that the level E2 of the photoelectric conversion output V returns to L level with this inversion to H level. changes to level E4.

In the morning, at time T3, when the photoelectric conversion output V exceeds the level E3, the first level detection circuit 2 is inverted again to the L level, the cyrisk Sl becomes non-conductive, and the light source 4 is immediately turned off.

When the photoelectric conversion output V reaches the level E4 at time T5, the output of the comparator CP2 is inverted and returned to the L level, so the sensitivity of the photoelectric conversion circuit 1 becomes low, and as shown in FIG. The photoelectric conversion output ■ decreases from level E4 to level E5. Note that the level E4 at the time of switching is set in advance so that when the sensitivity is switched at time T5, the level E5 is higher than the level El. Note that the diode D4. The resistor RIO and the capacitor C1 constitute a DC power supply, and the Zener diode D5 further stabilizes the voltage of this DC power supply.

In the embodiment described above, the resistor R2 is controlled to be shorted by the conduction/non-conduction operation of the diode D2, but in addition to this, for example, an electronic switch such as a transistor may be provided in parallel with the resistor R2. , the resistor R2 may be controlled to be short-circuited by conducting and non-conducting operations of this transistor.

In addition, in the explanation so far, switching the detection operation level is
The control is performed by switching the sensitivity of the photoelectric conversion circuit 1, but is not limited to this. For example, the output of the comparator CP2 is changed during the switching period of the detection operation level so that the voltage at point 72 in FIG. 2 is lowered. The detection operation level of the second level detection circuit may be switched by controlling the resistance value of the resistor R4 using a signal.

〔Effect of the invention〕

As described in detail above, the photogastric blinking control circuit according to the present invention is provided with a level detection circuit that generates either a switching light on/off operation signal depending on the illuminance, and a Detection that switches and controls the detection operation level of the level detection circuit so that a lighting operation signal is generated when the illuminance falls below the first level, and then a turn-off operation signal is generated when the illuminance is equal to or higher than a second level lower than the first level. An operation switching circuit is provided. Because of this configuration, in this blinking control circuit, the lights are turned off in the morning at a lower illuminance than the illuminance at which the lights are turned on in the evening, unlike the conventional ones. Therefore, the light source does not stay on for an unnecessarily long time in the morning, so it does not make people feel strange, and furthermore, power consumption can be saved and the life of the light source can be extended.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a blinking control circuit according to an embodiment of the present invention, FIG. 2 is a specific circuit diagram of a blinking control circuit according to an embodiment of the present invention, and FIG. FIG. 4 is a time chart showing changes over time in operating degrees, light source blinking operations, and changes in operation over time. FIG. 4 is an explanatory diagram of the relationship between changes over time in illuminance and automatic blinking time in a conventional blinking control circuit. 5...Detection operation switching circuit 6...Power supply Dl...
Photoconductive element D2...Diode Sl...Thyristor S2...Triac CPI, CP2...Comparator

Claims (4)

[Claims] (1) In a photoelectric blinking control circuit equipped with a switching element that blinks a light source based on a photoelectric conversion signal corresponding to the illuminance, one level that generates a signal for turning on/off the switching element according to the illuminance. A detection circuit is provided, and generates a lighting operation signal when the illuminance falls below a first level, and then generates a turning-off operation signal when the illuminance is equal to or higher than a second level lower than the first level. A photoelectric flashing control circuit comprising: a detection operation switching circuit for switching and controlling the detection operation level of the level detection circuit. (2) The detection operation switching circuit, based on the photoelectric detection signal,
2. The photoelectric blinking control circuit according to claim 1, which controls switching from a first level detection operation to a second level detection operation. (3) The photoelectric blinking control circuit according to claim 1 or 2, wherein the detection operation switching circuit switches the detection operation level by changing the sensitivity of photoelectric conversion. (4) The detection operation switching circuit, based on the photoelectric detection signal,
The photoelectric blinking control circuit according to claim 2 or 3, which performs control so that the detection operation at the second level is switched to the detection operation at the first level.