JPH01274387A - Illumination control circuit - Google Patents

Abstract

PURPOSE:To make it possible to prevent the lighting by a luminous load, by providing a means to control a switching device to prevent the current flow to a triac from the turning-on of an AC power source to the time when the output voltage of a DC power source circuit reaches a specific level. CONSTITUTION:From the turning-on of an AC power source AC to the time when the output voltage of a DC power source circuit 1 reaches a stable voltage, is provided the second voltage detecting circuit 7 to suppress forcibly the current flowing to the thyristor S1 of an ON/OFF switching circuit 5, that is, the current flowing to a triac S3. And in the circuit 7, until a Zener diode ZD4 detects that the AC power source AC is turned on and output voltage of the circuit 1 reaches a voltage to start the operation of an EE Zener circuit 4 and an inverting circuit 3, and lets flow the current, a transistor Q5 is OFF, and a base current flow to the base of the transistor Q5 through the illumination load L, the resistance R9 of a switch circuit 6, and the resistance R5 of a diode bridge DB. As a result, the transistor Q5 is ON and a transistor Q4 is short- circuited, and the gate current of the thyristor S1 is restricted from flowing when the current flows to a diac S2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a lighting control circuit that has both an automatic blinker function and a dimmer function.

[Prior art 1] Fig. 2 shows the basic circuit of this type of lighting control circuit, and this circuit includes a DC power supply circuit 1, a voltage detection circuit 2, an inverting circuit 3, an EE switch circuit 4, and an on/off circuit. It consists of a /off switching circuit 5 and a switch circuit 6 that controls the lighting load.

FIG. 3 shows a concrete circuit of a conventional example, and the conventional circuit will be explained next using this concrete circuit.

The DC power supply circuit 1 is an AC type [AC is rectified by a diode D, a resistor R1, and a Zener diode ZD.

to make it a constant voltage, and smooth it by capacitor C1.

The voltage detection circuit 2 detects the output voltage of the DC power supply circuit 1, and when the constant voltage of the DC power supply circuit 1 is input, the voltage detection circuit 2 detects the output voltage of the DC power supply circuit 1.
When the input of the Schmitt circuit consisting of becomes "H" and the Schmitt circuit outputs an "H" signal, and the voltage drops from the constant voltage and becomes less than the Zener voltage of the Zener diode ZD, the transistor Q, An input current flows through the Zener diode ZD2 and the resistor R4, turning on the transistor Q, and the input chip L1 of the Schmitt circuit is turned on.
As a result, an "L" signal is output. After that, when the output voltage of the DC power supply circuit 1 returns to a constant voltage, each part continues to operate normally.

The inverting circuit 3 is constituted by a D-type 7-lip 7a-tube FF, which inputs the output of the above-mentioned Schmitt circuit, that is, the output from the voltage detection circuit 2 as a clock, and receives a reset signal from the EE switch circuit 4. F
F is the EE switch circuit 4. When the reset signal is input, the Q output becomes L", and the output of the voltage detection circuit 2 * Hw
, "L" is input to the black terminal C, the Q outputs are sequentially inverted, and the Q outputs are sequentially inverted.

The EE switch circuit 4 is equipped with a transistor PH that detects external light, and when the external light level increases, that is, during the day, the phototransistor PH is turned on and the DC power supply circuit 1 is connected to the resistor R6 and the variable resistor. Current flows through the series circuit consisting of VR and phototransistor PH and does not charge capacitor C2, and at night, phototransistor PH
is turned off, and from the DC power supply circuit 1 to the resistor R6 and the variable resistor V
R.

The capacitor C2 is charged through the resistor R. In other words, during the day, the voltage across the capacitor C2 is set to L'', and at night, the voltage across the capacitor C2 is set to H'', and this voltage is inverted by the inverter IC and output, and the inverted output is further The signal is inverted by the inverter IC and passed through the capacitor C3 as a reset signal for the 7-lip 70-tube FF.

The on/off switching circuit 5 connects a series circuit of a transistor Q2, a resistor R2, and a transistor Q between the output terminals of the DC power supply circuit 1, and connects the base of the transistor Q to the output of the inverter IC3 through the resistor R1. It is connected to the end, and the transistor Q is connected to the H” of the EE switch circuit 4 during the daytime.
is turned on to short-circuit between the date cathodes of the thyristor Sl, and at night, the trunk Q is turned off by signals "L" and "M" of the EE switch circuit 4. During this night, the 7-rip 70-rub FF of the inverting circuit 3 inputs a reset signal to set the Q output to "L" and turn on the transistor Q2, so the thyristor is A current flows between the date cathode of S1.

In other words, during the daytime, the thyristor S1 is off, so the output terminal of the diode pre-7 and DB connected via the lighting load and the resistor R of the switch circuit 6 is turned off, and at night, the thyristor S1 is turned on. Therefore, the output ends of the diode DB are short-circuited by the thyristor S1 through the resistor R10. In this state, if the DC power supply circuit 1 is turned off and the output of the voltage detection circuit 2 is set to L'', then
Spot, Q output of 7-lip 70-tube FF of α circuit 3 is “H”
', transistor Q2 turns off and thyristor S
In order to cut off the current flowing between the date cathodes of diac S2, a charging current flows to capacitor C4 through diode DB and resistor R1°R1, charging capacitor C1, and when the voltage exceeds the breakover voltage of diac S2, The charge in the capacitor C1 is discharged between the date cathode of the thyristor SI through the resistor RI2 and the diac S, and the thyristor SI is turned on. As a result of this turning on, a current flows between the anodes and candes of the diode bridge DB, resistor RI0, and thyristor S with a phase delayed with respect to a half cycle of the commercial power supply.

The switch circuit 6 is a circuit in which a triac S is connected to an alternating current power source AC via a lighting load, and when the thyristor S of the on/off switching circuit 5 is turned on, a current is passed through the resistor R1 to the date of the triac S. Triac S
, to turn on the lighting load, and when the transistor Q2 of the inverting circuit 3 is turned on, the triac S is fully conductive and turns on the lighting load.
When transistor Q2 is turned off, resistors R1° and R
11. The triac S conducts at a phase angle determined by a time constant determined by the capacitor C1, and dims and lights up the lighting load.

[Problem to be Solved by the Invention 1] By the way, in the conventional circuit described above, the signals from the inverting circuit 3 and the EE switch circuit 4 are not correctly transmitted from the time when the AC power supply AC is turned on until the output of the DC power supply circuit 1 reaches a constant voltage. Before outputting, diode bridge DB, resistor R1゜l
The capacitor C1 is charged through Rl+, and the voltage across the capacitor C1 reaches the breakover voltage of the diac S2, which turns on the diac S2 and fires the thyristor S+.As a result, the triac S is turned on at a predetermined phase angle to provide illumination. There is a problem in that the lighting load is dimmed, that is, the lighting load Lfrt +7 lights momentarily lights up when the alternating current power source AC is turned on.

The present invention has been made in view of the above-mentioned problems, and its object is to provide a lighting control circuit that prevents the lighting load from turning on momentarily when AC power is turned on.

[Means for Solving the Problems 1] The present invention provides a switch circuit in which a triac is connected to an AC power source via a lighting load, a DC power circuit that rectifies and smoothes the AC power source and outputs a DC voltage, and an output voltage of this DC power circuit. There is a voltage detection circuit that inverts the output when the level of external light falls below a certain level, an EE switch circuit that detects the level of external light and inverts the output when the level falls below a certain level, and an EE switch circuit that detects a high level of external light. The above triac is turned off at the output of
In this conductive state, when the detected voltage level of the voltage detection circuit falls below a certain level, the output voltage of the DC power supply circuit reaches a certain level from the time the AC power is turned on, in a lighting control circuit comprising switching means for controlling the phase of the triac. Means for controlling the switching means so as not to cause the triac to conduct is provided.

[Function] In the above configuration, when the AC power is turned on, the switching means is turned off until the output voltage of the DC power supply circuit reaches a certain voltage or higher, so that malfunctions can be prevented when the power is turned on.

[Example 1 The present invention will be explained below with reference to Examples.

FIG. 1 shows a circuit according to an embodiment of the present invention. In this circuit, the on/off switching circuit 5 has a si risk S1 from when the AC power supply AC is turned on until the output voltage of the DC power supply circuit 1 reaches a stable voltage. conducts, that is, triac S
This circuit differs from the circuit shown in FIG. 3 in that a second voltage detection circuit 7 is provided to forcibly suppress conduction of .

This voltage detection circuit 7 has a series circuit of a Zener diode ZD3 and a resistor R13 connected between the output terminals of the DC power supply circuit 1, a transistor Qs connected in parallel to the transistor Q3 of the on/off switching circuit 5, and a Zener diode ZD3 connected in series with a resistor R13. The diode ZD is connected to the resistor R2, and the transistor Q whose base is connected to α via the resistor R8 is connected between the base and emitter of the transistor Q, and the base of the transistor Q5 is further connected via the resistor R11. It is connected to the positive output terminal of the diode Pritsuno DB.

Then, in the voltage detection circuit 7, the Zener diode ZD detects that the output voltage of the DC power supply circuit 1 has reached the voltage at which the EE switch circuit 4 and the inverting circuit 3 start operating when the AC power supply AC is turned on. Until it becomes conductive, transistor Ql is off for a long time, and transistor Q,
At the base of , there is a lighting load, a resistance R of the switch circuit 6,
A base current flows through the resistor R15, the resistor R15, and the resistor R15. Therefore, transistor Q is turned on, shorting transistor Q4, and suppressing the date current of thyristor S from flowing when diac S2 is conductive. In other words, the triac S is prevented from firing due to conduction of the thyristor S1.

Next, when the output voltage of the DC power supply circuit 1 rises and the Zener diode ZD4 becomes conductive, a base current flows through the transistor Q@, turning it on, thereby bypassing the base current of the transistor Qs. That is, the transistor Q5 is turned off and is thereafter set to the normal operating state, and the inverting circuit 3. On/off switching circuit 5 according to the output from the EE switch circuit 4
will be able to control.

[Effects of the Invention] The present invention provides a lighting control circuit having a groove structure as described above, and a switching means for preventing the triac from conducting from the time when the AC power is turned on until the output voltage of the DC power supply circuit reaches a certain level. Since we have a means to control
This has the effect of preventing the triac from becoming conductive and lighting the lighting load during an unstable period from when the AC power is turned on until the output voltage of the DC power supply circuit stabilizes.

[Brief explanation of the drawing]

FIG. 1 is a specific circuit diagram of an embodiment of the present invention, FIG. 2 is a circuit diagram of a conventional example, and FIG. 3 is a specific circuit diagram of the same. 1 is a DC power supply circuit, 2 is a voltage detection circuit, 3 is an inversion circuit,
4 is an EE switch circuit, 5 is an on/off switching circuit, 6 is a switch circuit, 7 is a second voltage detection circuit, AC is an alternating current power supply, SI is a thyristor, S2 is a triac, S is a triac, and L is a lighting load. It is. Agent Patent Attorney Ishi 1) Ai Shichi

Claims (1)

[Claims] (1) A switch circuit in which a triac is connected to an AC power source via a lighting load, a DC power circuit that rectifies and smoothes the AC power source and outputs a DC voltage, and outputs an output when the output voltage of this DC power circuit drops below a certain level. A voltage detection circuit that inverts the external light level, an EE switch circuit that detects the external light level and inverts the output when the level falls below a certain level, and an EE switch circuit that turns off the triac at the output when the EE switch circuit detects a high external light level. The switching means makes the triac fully conductive at the output when the EE switch circuit detects a low external light level, and controls the phase of the triac when the detected voltage level of the voltage detection circuit becomes below a certain level in this conductive state. A lighting control circuit comprising: means for controlling the switching means so as not to conduct the triac from the time when the AC power supply is turned on until the output voltage of the DC power supply circuit reaches a certain level. circuit.