JPH03116698A - Discharge lamp lighting device - Google Patents

Abstract

PURPOSE:To realize a three-wire light-adjustment lighting device with simple circuit configuration by providing a light-adjustment control circuit for receiving signals that an a.c. power supply is phase-controlled for a light adjustment level and controlling the output of an inverter circuit. CONSTITUTION:A light-adjustment control circuit 33 is provided for receiving signals that an a.c. power supply AC is phase-controlled for a light adjustment level 37 and controlling the output of an inverter circuit. A waveform shaping circuit 31 converts the a.c. signals phase-controlled for a light adjustment level into PWM(pulse width modulation) signals, e.g. with the pulse width corresponding to their continuity angles or d.c. signals with the potential level varied with a light adjustment level, which are input into the light-adjustment control circuit 33. The light-adjustment control circuit 33 varies the drive frequency of an inverter circuit in accordance with such signals and performs light adjustment of a discharge lamp 25. It is thus possible to realize a three-wire light- adjustment lighting device and intend easy wiring and low cost of the device.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a discharge lamp lighting device, and particularly to a three-wire discharge lamp lighting device that controls the output of an inverter circuit using a signal obtained by controlling the phase of a power source as a dimming signal. Regarding.

[Prior Art] FIG. 3 shows a schematic configuration of a conventional dimmable discharge lamp lighting device. In the device shown in the figure, alternating current power AC is applied to the lighting device via terminals TI and T2, and the diode bridge 1 and smoothing capacitor 3 convert this into direct current and apply it to the inverter circuit 5. On the other hand, terminals T3, 7
A PWM signal having an amplitude of, for example, 12 V is applied as a dimming signal between the inverters 4 and the alternating current power supply AC, and this dimming signal is insulated via the photocoupler 7 and applied to the inverter circuit 5. The inverter circuit 5 generates a high frequency power source at a frequency corresponding to the pulse width of this dimming signal to light the discharge lamps 9 and 11. As a result, terminal T3. It was possible to control the dimming level of the discharge lamp by changing the duty cycle of the dimming signal applied during T4.

[Problems to be Solved by the Invention] In such a conventional discharge lamp lighting device, it is necessary to apply an AC power source and a dedicated dimming signal whose potential level is different from that of the AC power source to the lighting device, and the device The problem was that the number of wires was large and the workability was poor. Furthermore, components such as photocouplers or transformers are required to insulate the dimming signal from the power supply, which increases the cost of the device.

Furthermore, there is a problem that the power supply line and the dimming signal line may be incorrectly connected during construction wiring, which may destroy the device.

An object of the present invention is to make it possible to realize a 3-wire dimming lighting device with a simple circuit configuration, in view of the problems with the conventional devices described above, and to improve wiring workability, reliability, and device cost. The goal is to bring things down.

[Means for Solving the Problems] A discharge lamp lighting device according to the present invention includes a rectifier circuit that converts input AC power to DC, an inverter circuit that operates based on the output of the rectifier, and a DC power source that converts the AC power to a dimming level. The present invention is characterized by comprising a dimming control circuit that receives a signal whose phase is controlled accordingly and controls the output of the inverter circuit based on this signal.

[Operation] In the above-described configuration, the rectifier circuit generates DC power from the input AC power, and the inverter circuit operates with this DC power to generate high-frequency power for lighting the discharge lamp.

On the other hand, a signal obtained by controlling the phase of the AC power source is input to the dimming control circuit, where it is converted into a PWM signal or a DC signal.
For example, the oscillation frequency of an inverter circuit is controlled by the duty cycle of the WM signal or the potential level of the DC signal, and the discharge lamp is dimmed. Therefore, in the device according to the present invention, it is possible to use one of the AC power lines and one of the phase control signal lines in common,
A 3-wire dimming lighting device can be realized.

[Example] Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 1 shows a schematic configuration of a discharge lamp lighting device according to an embodiment of the present invention. The lighting device shown in the figure drives a rectifying and smoothing circuit having a diode bridge 13 and a smoothing capacitor 15, switching transistors 17 and 19 connected to the output of this rectifying and smoothing circuit, capacitors 21 and 23, and transistors 17 and 19. A driving circuit 35, an inverter transformer 27, a starting capacitor 29, a waveform shaping circuit 31, and a dimming control circuit 33 are provided. A discharge lamp 25 is connected to the secondary coil of the inverter transformer 27. Further, such a discharge lamp lighting device has three input terminals T5. TO, 3 with T7
It is a wire circuit, with an AC power supply connected between terminals 75 and 76, and terminals T7. is connected to one terminal of an AC power source via a phase control dimmer 37 using, for example, a thyristor. Note that terminal T5. T6 is connected to the input of the diode bridge 13 of the discharge lamp lighting device, and terminal T7 is connected to the waveform shaping circuit 31.

In the device of FIG. 1, terminals T5. The alternating current power supply AC applied between T8 is converted to direct current by the diode bridge 13 and the smoothing capacitor 15, and the transistor 17.1
9, capacitors 21 and 23, and a drive circuit 35. Transistors 17 and 19 are alternately turned on and off by a high frequency switching signal supplied from drive circuit 35, and the high frequency power generated thereby is supplied to inverter transformer 27.
The voltage is applied to the discharge lamp 25 via the electric current, and the discharge lamp 25 is lit in a well-known manner.

On the other hand, the phase of the alternating current power supply AC is controlled by the phase control dimmer 37 according to the dimming level, and is applied to the waveform shaping circuit 31 via the terminal T7. The waveform shaping circuit 3 converts this phase-controlled AC signal into, for example, a PWM (pulse width modulation) signal having a pulse width corresponding to its conduction angle, or converts the phase-controlled AC signal into a PWM (pulse width modulation) signal whose potential level changes depending on the dimming level. The signal is converted into a signal and input to the dimming control circuit 33. The dimming control circuit 33 changes the drive frequency of the inverter circuit based on this signal to dim the discharge lamp 25.

FIG. 2 shows a specific circuit configuration of a discharge lamp lighting device according to another embodiment of the present invention. The device in the figure has terminals T5. to which AC power is applied. Filter circuit 39 connected to T8
, diode bridge 13 and smoothing capacitor 15
A rectifying and smoothing circuit constituted by a switching transistor 17.19, a capacitor 21.23 which constitutes a half-bridge inverter circuit together with the switching transistor 17.19, a driving integrated circuit 41 and a driving circuit which constitute a driving circuit. It is composed of a transformer 43, a dimming signal generation circuit 45, and the like. The dimming signal generation circuit 45 includes a Zener diode z1 and a transistor Ql.

It is composed of Q2, resistors R1, R2, . . . , R6, capacitor C1, etc. Further, the transistor Q3, resistors R7, R8, etc. connected to the integrated circuit 41 are circuits for controlling the oscillation frequency of the driving oscillator of the inverter circuit. Further, one terminal of an AC power source is connected to the terminal T7 via a phase control dimmer 37, as in the case of FIG. Therefore, the terminal T6 serves as both an AC power supply terminal and a phase control signal terminal. Incidentally, a starting capacitor 47.49 and a discharge lamp 51.53 are connected to the secondary side of the inverter transformer 27 in a well-known manner.

In the circuit of FIG. 2, terminals T5. The AC power applied between TO is applied to diode bridge [3 through filter circuit 39, converted into DC by diode bridge 13 and smoothing capacitor 15, and supplied to the inverter circuit. On the other hand, the driving integrated circuit 41 is, for example, a TL494 type integrated circuit manufactured by the present applicant, and includes an oscillation circuit for generating a high frequency signal for driving the inverter. A high frequency signal supplied from this oscillation circuit or the like is applied to each transistor 17.19 via the drive transformer 43, and the inverter circuit operates to light each discharge lamp 51.53.

On the other hand, the phase control dimmer 37 applies a phase control signal having a conduction angle corresponding to a desired dimming level to the dimming signal generation circuit 45 via the terminal T7.

In the dimming signal generation circuit 45, by applying this phase control signal to the transistor Ql via a voltage divider circuit composed of resistors R1 and R2 and a Zener diode Z1, the phase control signal is proportional to the conduction angle of the phase control signal. A PWM signal having a predetermined amplitude and a pulse width is generated. This PWM
The signal is further applied to transistor Q2 and integrated by an integrating circuit including resistor R6 and capacitor C1 to obtain a DC signal whose potential changes depending on the dimming level, and this DC signal is applied to the base of transistor Q3. . As a result, the impedance between the collector and emitter of transistor Q3 changes according to the dimming level,
The oscillation frequency of the oscillator 55 within the driving integrated circuit 41 is controlled. Accordingly, the oscillation frequency of the inverter circuit changes depending on the desired dimming level, thereby dimming the discharge lamp 51, 53 in a known manner.

[Effects of the Invention] As described above, according to the present invention, it is possible to realize a 3-wire dimming lighting device without using an insulating means such as a photocoupler or a transformer, and it is possible to simplify the wiring and to The cost of the device can be reduced. Further, even if one of the power supply lines and the phase control signal are incorrectly connected, the device will not be destroyed. Furthermore, since dimming is performed by frequency control of the inverter circuit, optical ripples are smaller than in conventional two-wire phase control, and high frequency components of the input current are also reduced. Furthermore, it is possible to use a phase control dimmer, which has been widely used in the past, and it is possible to prevent an increase in the price of the device.

[Brief explanation of drawings]

FIG. 1 is a block circuit diagram showing a general configuration of a discharge lamp lighting device according to one embodiment of the present invention, and FIG. 2 is a block circuit diagram showing a specific configuration of a discharge lamp lighting device according to another embodiment of the present invention. FIG. 3 is a schematic block circuit diagram showing a conventional discharge lamp lighting device. 1.13; diode bridge, 3.15; smoothing capacitor, 5; inverter, 7; photocoupler, 9.11, 25, 51, 53. Discharge lamp, 17.19; Switching transistor, 21.23. Inverter capacitor, 35; Drive circuit, 27; Inverter transformer, 29.47.49, Starting circuit 31; Waveform shaping circuit, 33; Dimming control circuit, 37; Phase control dimmer, 39; Filter circuit, 41 ; Driving integrated port; 43; Driving transformer; 45: Dimming signal generation circuit. Ndensa,

Claims (1)

[Claims] 1. a rectifier circuit that converts input AC power into DC; an inverter circuit that operates based on the output of the rectifier; and a signal that controls the phase of the AC power in accordance with a dimming level, and the inverter circuit receives a signal that controls the phase of the AC power in accordance with the dimming level. A discharge lamp lighting device comprising: a dimming control circuit that controls the output of the discharge lamp lighting device.