JPS5835899A - Circuit for firing discharge lamp - 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 The present invention relates to a discharge layer lighting circuit, particularly to a ballast.
The present invention relates to a discharge layer lighting circuit suitable for full use of a reactor.

In conventional discharge layer lighting circuits, a reactor is connected in series with the discharge light as a ballast for limiting the current of the discharge light. However, in this method, the AC source frequency is 50 or 60H.
Since the z is low, the inductance of the ballast becomes large, on the order of several mH, and therefore the ballast has the disadvantage that both its volume and weight are large.

An object of the present invention is to provide a discharge lamp lighting cycle U+ in which a compact and lightweight glue handle can be used as a ballast by effectively exhibiting the effect of reducing inductance through high-frequency switching of the AC power supply voltage. be.

The present invention has confirmed through experiments that a discharge lamp lights up even if the inductance as a ballast is a small value of several hundred μH, and by using a single switching element, it is possible to control the AC frequency on an AC power supply. It is designed to chop at a high frequency.

An embodiment of the present invention will be described with reference to FIG.

In this embodiment, a semiconductor switching element that performs high-frequency switching and has a self-extinguishing ability, such as a gate turn-off thyristor (hereinafter referred to as GTO), is used. As shown in the figure, the anode of diode 2 is connected to the anode of diode 1, the cathode of diode 3 is connected to the cathode of diode 2, the cathode of diode 4 is connected to the anode of diode 3, and the cathode of diode 4 is connected to the anode of diode 3. The anode of the diode 5 is connected to the anode, the cathode of the diode 6 is connected to the cathode of the diode 5, the anode of the diode 6 is connected to the cathode of the diode 1, and the anode of the diode 1 and the cathode of the diode 6 are connected to each other. A reactor 7 is connected between the cathode and the diode 2.
0 cathode and the anode of the diode 5, a G
TO8 is connected, a radiation light 9 is connected between the anode of the diode 3 and the AC power terminal 11, a cathode of the diode 1 and the AC power terminal 12 are connected, and the AC power terminal 11 is connected to the cathode of the diode 1. Zener diodes 13 and 14 connected in series in opposite directions to the AC power source 10 are connected in parallel between the AC power source terminal 12 and the AC power source terminal 12.

When the GTO 8 is turned on when the AC power terminal 11 has a positive voltage between the AC power terminals 11 and 12, the discharge light 9
When a voltage is applied to the terminal 1 and the applied voltage becomes lower than the starting voltage of the flashlight 9, the AC power supply 10 connects the AC power supply terminal 1.
1, discharge light 9, diode 3, GTO8, diode 5
, the reactor 7, the diode 1, the AC power supply terminal 12, and the AC power supply 10 in a closed circuit, and the emitting light 9 is turned on.

When GTO8 is turned off, it discharges! When the voltage applied to the reactor 9 disappears, the reactor 7 is reset by a closed circuit constituted by the diode 1 and the diode 6. When the GTO 8 is turned on and off in this manner, voltage is applied to the lamp 9 at a high frequency.

Next, when the AC power supply terminal 12 becomes a positive voltage, the GTO
8 is turned on, a voltage is applied to the discharge lamp 9, and when it exceeds the starting voltage, the AC power supply 10, AC power supply terminal 12, diode 6, reactor 7, diode 2, GTO 8, diode 4, discharge lamp 9, AC A current flows through a closed circuit composed of the power supply terminal 11 and the AC power supply 10, and the discharge lamp 9 is turned on. When the GTO 8 is completely turned off, the voltage applied to the discharge lamp 9 disappears, and the reactor 7 is reset by a closed circuit constituted by the diode 1 and the diode 6.

When the GTO 8' is turned off, a whisker-like overvoltage generated from the AC power supply 10 is clamped by the Zener diode 13 or the Zener diode 14. According to the embodiment, by chopping the AC voltage at high frequency using at most one GTO, the inductance of the discharge lamp ballast can be reduced, which has the effect of making the ballast smaller and lighter. .

FIG. 2 shows another embodiment of the present invention, in which the actuator shown in FIG. 1 is replaced with a primary winding 15 of a pulse transformer. Further, a variable resistor 17 is connected in parallel to the secondary winding 16 of this pulse transformer. In this embodiment, by applying a load to the secondary winding d16 of the Noculus transformer, the inductance of the primary winding 15 of the pulse transformer can be changed, and the power given to the storm light 9 can be made variable. effective.

According to the present invention, since the alternating current power supply voltage can be chopped at high frequency, the ballast can be made smaller and lighter.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing one embodiment of the invention, and FIG. 2 is a circuit diagram showing another embodiment of the invention.

Claims (1)

[Scope of Claims] 1. In a discharge layer lighting circuit in which an AC power supply and a ballast are connected in series to a discharge lamp, the ballast has a first part, a second part, and a second part. Third
A series body of diodes and a fourth diode. 5. The series body of the sixth diode is connected in parallel, and the connection point of the first and second diodes and the fourth. A reactor is connected between the connection points of the fifth diode, and the connection points of the second and third diodes and the fifth.
A discharge layer lighting circuit comprising a high-speed switching element connected between the connection points of the sixth diode. 2. The acid lamp lighting circuit according to claim 1, wherein the reactor is a primary winding of a pulse transformer. 3. The open-air lighting circuit according to claim 1 or 2, wherein the high-speed switching device is a gate turn-off thyristor.