JPH0357196A - Lighting load control device - Google Patents

Abstract

PURPOSE:To reduce delay in the change of light output at the time of power source cutting by providing a control circuit by which a dimmer signal is converted into a no-voltage signal faster than the damping of d.c. voltage obtained by rectifying and smoothing an a.c. power source at the time of power source cutting. CONSTITUTION:A transistor Tr4 is provided for lowering a collector output of a transistor Tr1 to a ground level, and the transistor Tr4 is turned 'ON' at the time of power source cutting by a control circuit including a photodiode PD and a phototransistor PT. Collector potential of the transistor Tr1 is forced to be lowered to a ground level, whereby a dimmer signal Vd is immediately cut off. A high frequency converter circuit 3 works by a residual charge of a condenser C0. Since On-duty of the dimmer signal Vd is minimized, light output of a fluorescent lamp 4 is so controlled to be maximized. The residual charge of the condenser C0 is rapidly consumed thereby, and the fluorescent can thus be put off immediately.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a lighting load control device that controls the lighting load by providing a dimming signal from a dimmer to a high-frequency lighting device via a signal line. It is. [Prior Art] Figure 2 is a circuit diagram of a conventional lighting load control device. This lighting load control device consists of a high frequency lighting device X and a light control device Y. The high-frequency lighting device
The DC voltage obtained by the smoothing capacitor C0 is input to the high frequency conversion circuit 3, where it is converted into a high frequency voltage and the fluorescent lamp 4 is turned on. The high frequency conversion circuit 3 connects the light control device Y to the light control signal line 1. ,1. The fluorescent lamp 4 is equipped with a control circuit that varies the light output of the fluorescent lamp 4 according to a dimming signal transmitted through the fluorescent lamp 4. Next, the circuit configuration of the light control device Y will be explained. The AC voltage of the AC power supply Vs is stepped down by a step-down transformer T1,
diode bridge d. Full wave rectified by B I,
Charge capacitor C1. The voltage of the capacitor Cl is made constant by the three-terminal regulator Q, and the capacitor C2 is charged to become a DC power source E2 with a low DC voltage (for example, about 12 cm).The triangular wave generating circuit 5 is powered by the DC power source E2. consists of a capacitor, a resistor that charges the capacitor with a current from the DC power source E2, and a switching circuit that discharges the capacitor when the charging voltage of the capacitor reaches a predetermined voltage. A triangular wave voltage Va of about IKHz) is applied to the inverting input terminal of the comparator 6.The triangular wave voltage Va obtained by the triangular wave generating circuit 5 is not a strict triangular wave, but has a waveform with respect to the time axis as shown in FIG. It is assumed that the voltage increases non-linearly.The voltage of the DC power supply E2 is divided by the variable resistor VR. and the semi-fixed resistors VR, VR., and is applied to the non-inverting input terminal of the comparator 6 as the reference voltage vb. The semi-fixed resistors VR, ,VR, determine the upper limit value Vb and lower limit value Vb2 of the reference voltage vb obtained from the variable resistor VR.The output terminal of the comparator 6 is connected via the resistor R1. The emitter of the transistor Tr is connected to the base of the transistor Tr.The emitter of the transistor Tr is connected to the DC power supply E.
The collector is connected to the positive electrode of the DC home source E2 via the resistor R2, and the collector is connected to the negative electrode of the DC power source E2 via the resistor R2.
Connected to the base of r2. The collector of the transistor Tr2 is connected to the positive electrode of the DC power source E2, and the emitter is connected to the negative electrode of the DC power source E2 via a resistor R4, and also to the base of the transistor Trl via a resistor R3. The collector of the transistor Tr3 is connected to the positive electrode of the DC power source E2, and the emitter is connected to the negative electrode of the DC power source E2 via a resistor R5.

Then, a dimming signal Vd is obtained from both ends of the resistor R.
In other words, the transistor Tr+ and the resistor R. , R2 constitute a common emitter type inverting amplifier circuit, and the transistor Tr2 and the resistor R, and the transistor Tr3 and the resistor R
3. R5 constitutes a grounded collector (emitter follower) type impedance conversion circuit. Note that the impedance conversion circuit is arranged at the output stage of the dimmer Y because the dimmer signal line fl. ,l, is often extended for a long time, so
In order to prevent the dimming signal from attenuating, the impedance of the dimming signal is reduced. The operation of the light control device Y will be explained below with reference to FIG. FIG. 3(a) shows the relationship between the reference voltage Vb obtained from the variable resistor VR and the triangular wave voltage Va obtained from the triangular wave generating circuit 5. The reference voltage vb can be set continuously from a high voltage vb1 to a low voltage vb2. Triangular wave voltage V obtained from the triangular wave generating circuit 5
When a is lower than the reference voltage vb, the output terminal of the comparator 6 becomes "High" level, so the transistor T
r. turns on, its collector potential Ve drops, and
The dimming signal Vd becomes "Los" level. On the other hand, the triangular wave voltage Va obtained from the triangular wave generating circuit 5 is the reference voltage v
When the output terminal of the comparator 6 becomes “L am
" level, the transistor Tr is turned off, its collector potential Vc rises, and the dimming signal Vd becomes "
As a result, as shown in Fig. 3(b)
, (A dimming signal Vd as shown in e7 is obtained. Figure (b) shows the dimming signal Vd when the reference voltage vb is a high voltage Vb1, and the on-duty (tl/T) is small. In addition, in the same figure (e), the reference voltage vb is a low voltage vb
, and the on-duty (t2/T) is large. Reference voltage vb is variable resistor VR2
From high voltage Vb1 to low voltage ■b by operating
Since the on-duty of the dimming signal Vd can be set to any voltage up to 2, the on-duty of the dimming signal Vd can be set to any value from the minimum value shown in the figure (b) to the maximum value shown in the figure (c). It is something that can be done. [Problem M to be solved by the invention] In the above-mentioned conventional example, the high frequency conversion circuit 3 converts the dimming signal V
The controller is equipped with a control circuit that maximizes the optical output when the on-duty of d is at a minimum, and minimizes the optical output when the on-duty is at a maximum. Now, if the on-duty of the dimming signal Vd is increased and the power switch SW is shut off when the optical output is at its minimum, the DC power supply E2 of the dimming device Y
is the smoothing capacitor C + . Since it gradually decreases over time due to the influence of C2, the dimming signal Vd also remains generated for a while. On the other hand, the high-frequency lighting device
Since the power consumption is also low, the charging voltage is as shown in Figure 4 (a
), the power gradually decreases after the power switch SW is turned OFF. For this reason, the fluorescent lamp 4 gradually disappears with a slight discharge over a period of time, and the light output from the fluorescent lamp 4 continues during the time indicated by diagonal lines in the diagram, causing a problem that the user feels uncomfortable. there were. The present invention has been made in view of these points, and its purpose is to provide lighting that can immediately cut off the dimming signal when the power is cut off, thereby preventing delays in changes in the light output of the lighting load. Our purpose is to provide a load control device. [Means for Solving the Problems] In the present invention, in order to solve the above problems, the first
As shown in the figure, there is a high-frequency lighting device lx that converts the DC voltage obtained by rectifying and smoothing the AC power supply Vs into a high frequency and lighting a lighting load (for example, a fluorescent lamp 4), and A signal t! is supplied to the high frequency lighting device dimming signal Vd via e 3 , e,
The dimming signal Vd is a rectangular wave signal in which the proportion of the voltage-bearing section in one period is variable, and the high-frequency lighting device This device increases the light output of the lighting load as the ratio of the voltage section decreases, and controls the dimming signal Vd to a no-voltage signal faster than the attenuation of the DC voltage obtained by rectifying and smoothing the AC power supply Vs when the power is cut off. It is characterized by being equipped with a circuit. [Function] In this way, in the present invention, the dimming signal Vd is made into a no-voltage signal faster than the attenuation of the DC voltage obtained by rectifying and smoothing the AC power supply Vs when the power is cut off, so that the power supply There is no delay in the change in light output when the light is cut off. [Embodiment] Figure 1 is a circuit diagram of an embodiment of the present invention. In this embodiment, in the conventional example shown in FIG. 2, the transistor Tr.
A transistor Tr. for dropping the collector output of the transistor Tr. is provided, and this transistor Tr. A control circuit including a light emitting diode PD and a phototransistor PT turns on the light when the power is cut off. The structure of the control circuit will be explained below. The secondary winding of the step-down transformer T is provided with a current-limiting resistor R. via the diode bridge DB. The AC input terminal of the diode bridge DB2 is connected, and the light emitting diode PD is connected to the DC output terminal of the diode bridge DB2. A light signal generated from this light emitting diode PD is received by a phototransistor PT. Phototransistor PT is capacitor C
, are connected in parallel to both ends of the . This capacitor C is connected to the DC power supply E2 via a resistor R6. In addition, the capacitor C is connected to the transistor Tr via the resistor R.
It is connected between the base and emitter of 4. The collector and emitter of the transistor Tr< are the transistor Tr,
are connected to the collector and emitter of the The operation of the above circuit will be explained below. When the power switch SW is turned on, the light emitting diode PD generates an optical signal, and the phototransistor PT that receives this optical signal becomes conductive, so that the voltage across the capacitor C does not rise. Therefore, the transistor Trn is kept in an off state, and the light control device Y operates in the same manner as the conventional example shown in FIG.
Next, when the power switch SW is turned off, the light emitting diode PD stops generating an optical signal and the phototransistor PT becomes non-conductive, so that the residual charge in the capacitor C2 is transferred to the capacitor C and the capacitor C through the resistor R. , and the capacitor C is charged. As a result, capacitor C,
The voltage across the transistor T increases through the resistor R.
A base current flows through rn, and the transistor Tr< turns on. As a result, the transistor Tr. Since the collector potential of is forcibly lowered to the ground level, the dimming signal Vd is immediately cut off. At this time, the high frequency conversion circuit 3 is operating with the residual charge in the capacitor C0, but since the on-duty of the dimming signal Vd has become minimum, it controls the light output of the fluorescent lamp 4 to maximize it. .

For this reason, capacitor C. The residual charge of is rapidly consumed, and its voltage drops rapidly as shown in Figure 4(b). Therefore, in this embodiment, even if the power switch SW is turned OFF when the light output is low, the fluorescent lamp 4 can be quickly turned off. In addition, power switch SW 31! When the fluorescent lamp 4 is turned off, it momentarily changes from the dimming state to the maximum lighting state, but the time is short and the capacitor C. As the voltage rapidly decreases, the light output also decreases rapidly, so there is no visual discomfort. In the above circuit, the capacitor C is provided for the purpose of maintaining the off state of the transistor Tr< since the optical signal of the light emitting diode PD stops near the zero cross of the AC power supply Vs. If the capacitance of this capacitor C is too large, the power switch SW is cut off and the light signal from the light emitting diode PD is stopped.
r. Since it takes a long time to turn on the capacitor C, the smaller the capacitance of the capacitor C, the better, within the range that achieves the above purpose.

Next, in the conventional circuit shown in FIG.
Consider the case where the first power switch SW1 is inserted at +'2 and the second power switch SW2 is inserted at the power input side of the dimmer Y. In this case, when the on-duty of the dimming signal is minimized by the dimmer Y and the light output by the high-frequency lighting device X is maximized, if the power switch SW is shut off, the fluorescent lamp 4 is immediately turned off and the When the switch SW2 is turned off, the fluorescent lamp 4 remains in the maximum lighting state.

Next, when the on-duty of the dimming signal is maximized by the dimmer Y and the light output by the high-frequency lighting device X is minimized, if the power switch SW is shut off, the dimmer signal remains output. Therefore, the fluorescent lamp 4 gradually goes out as the voltage of the DC power source E1 attenuates. Therefore, in this case, as shown in FIG. 5, when the power is cut off on the side of the high-frequency lighting device Relay R to disconnect
By adding y, the input of the dimming signal Vd can be cut off, and the fluorescent lamp 4 can be turned off immediately when the power switch sw is cut off. The switch sw consists of a normally open contact of the relay Ry, and is connected in series to the dimming signal line l. When the power switch sw1 is cut off, the excitation of the relay R is canceled and the switch sw is cut off. Furthermore, when the on-duty of the dimming signal is maximized by the dimmer Y and the light output by the high-frequency lighting device X is minimized, if the power switch sw2 is shut off, the dimmer signal remains on for a while. Therefore, the fluorescent lamp 4 reaches its maximum lighting state after a while. In this case, by using the light control device 1tfY shown in FIG. 1, it is possible to immediately shift the fluorescent lamp 4 to the maximum lighting state when the power switch sw2 is turned off. [Effects of the Invention] As described above, the present invention includes a high-frequency lighting device and a dimming device that operate using a DC voltage obtained by rectifying and smoothing an AC power source, and the high-frequency lighting device consists of a rectangular wave signal. In a lighting load control device that increases the light output of the lighting load as the proportion of the voltage-containing section in one cycle of the dimming signal decreases, the attenuation of the DC voltage obtained by rectifying and smoothing the AC power supply when the power is cut off is Since the dimming signal is made to be a voltage-free signal quickly, there is no delay in the change in the light output of the lighting load when the power is cut off.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram of an embodiment of the present invention, Fig. 2 is a circuit diagram of a conventional example, Fig. 3 is an operating waveform diagram of the same as above, and Fig. 4 (a) is an operating waveform when power is cut off in the conventional example. 4(b) are operational waveform diagrams when power is cut off according to the present invention, and FIG. 5 is a circuit diagram of another embodiment of the present invention. Vs is an AC power supply, SW is a power switch, C. ,CC2
is a smoothing capacitor, DB is a diode bridge, X is a high-frequency lighting device, Y is a dimmer, 2 is a full-wave rectifier, and 4 is a fluorescent lamp.

Claims (1)

[Claims] (1) A high-frequency lighting device that converts a DC voltage obtained by rectifying and smoothing an AC power source into a high frequency to light a lighting load, and a high-frequency lighting device that is powered by the DC voltage obtained by rectifying and smoothing an AC power source. It consists of a dimmer device that provides a dimmer signal via a signal line, and the dimmer signal is a rectangular wave signal in which the proportion of the voltage-carrying section in one cycle is variable, and a high-frequency lighting device provides a dimmer signal that This device increases the light output of the lighting load as the proportion of the voltage-carrying section in the period decreases, and converts the dimming signal into a no-voltage signal faster than the attenuation of the DC voltage obtained by rectifying and smoothing the AC power when the power is cut off. 1. A lighting load control device comprising a control circuit.