JPS5838497A - Dimmer for 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 dimming device wtK for a discharge lamp that lights the discharge lamp using high frequency waves and controls the dimming.

Discharge lamps such as fluorescent lamps 2-3K using all inverters
Attempts have been made in the past to turn on the light at a high frequency of H2 or higher and to perform dimming, since this provides good dimming with less flickering. A device as shown in FIG. 1 has been known as a device capable of dimming by controlling the input voltage of an inverter by phase control or the like.

In Fig. 1, 1 is a commercial AC power supply (hereinafter referred to as AC power supply), 2 is a full-wave rectifier, 3 is an inverter, which here consists of a constant current type push-pull transistor inverter, and 4 is a discharge 5 is a thyristor, and 6 is a phase control device for controlling conduction of the thyristor.

Inverter 3I, switching transistor 7a, output 7b, output transformer 8, harmonic choke 9
, a capacitor 10, a choke coil 11, etc., and when a DC voltage is applied to the inverter 3, oscillation starts due to the action of the base feedback winding 8B, and a high frequency output voltage is generated in the secondary winding 8s.

That is, the AC power supply 1 is connected to the input end of the full-wave rectifier 2, and its positive output end is connected to the midpoint of the collector windings 8c1, 8c2 of the output transformer 8 via the high frequency choke coil 9. So, this collector winding is 8cI + 8
Each end of e2 is a switching transistor 7&, 7b.
connected to each collector.

The output transformer 8 has a collector winding a8c++8c2, a secondary winding 8S, and a base feedback winding Ii! 8B'f! -, and both ends of the pace feedback winding 8B are connected to each pace of the switching transistors 7h and 'Ib. Resistors R+ and R2 are connected in series between the switching transistors 7a and 7b. The connection point between resistors R1 and R2 is connected to the midpoint between collector windings 8cl and 8C2.

A capacitor 1 is connected to both ends of the secondary winding 8S of the output transformer 8.
0 is connected to the discharge lamp 4 via the choke coil 11.

Furthermore, a thyristor 5 is connected between the negative output terminal of the full-wave rectifier 2 and the emitter of the switching transistor 7b. The -6 output end of the phase control device 6 is connected between the cathode and dart of the thyristor 50, and the input end of the phase control device 6 is connected to the AC power supply 1.

Next, the operation of the conventional discharge lamp dimming device configured as described above will be explained. The AC power supply 1 is turned on, and the full-wave rectifier 2 generates a DC voltage of a smooth pulsating current by rectifying the AC power supply 1 as shown in FIG. 2G). When the thyristor 5 is in conduction 1- for the entire period of each half cycle of the AC power supply 1 by the signal of the phase control device 6, the inverter 3
Due to the oscillation operation, the secondary winding 8S of the output transistor 8
In this case, high-frequency output voltages as shown in FIG. 2(b) are generated and applied to the discharge lamps 4.

At this time, a current flows through the discharge lamp 4 as shown in FIG. Here, the current of the discharge lamp 4 is To
There is a pause period during which no current flows, but this is the period until the voltage of the secondary winding 8S of the output transformer 8 reaches a voltage sufficient to re-ignite the discharge lamp 4. corresponds to

Here, if the phase control device 6 sets the phase at which the thyristor 5 starts to conduct completely to a phase pressure of θ1 as shown in FIG. Moving on to electric light 4.

Correspondingly, the rest period of the current also becomes longer, the current value decreases, and the light output thereof also decreases.

In this way, light control is performed by changing the phase at which the thyristor 5 starts conducting.

In addition to the above method of controlling the direct current and voltage input from the AC power supply 1 to perform dimming, there is also a conventional method of controlling the supply of pace current of a transistor inverter to perform dimming, as shown in Fig. 3. There is a device that performs this (1) In FIG. 3, the same reference numerals indicate all the parts corresponding to those of the device in FIG. 1, and the explanation thereof will be omitted.

In this Figure 3, the pace power supply circuit 12 has been newly added,
The first thyristor 5 is omitted.

The pace power supply circuit 12 is connected to the emitter of the control transistor 13 through both ends of the pace feedback winding 811 and through the resistors 14a and 14b, and the collector of the control transistor 13 is connected to the positive side of the full-wave rectifier h2. Connected to the output end. The output terminal of the phase control device 6 is connected to the pace of the control transistor 13. This pace power supply circuit 12 controls the supply of base current to the switching transistors 7a and 7b.

Even in the conventional discharge lamp dimming device configured as shown below, when the control transistor 13 is made conductive by the signal from the phase control device 6 and an output voltage similar to that shown in FIG. 14a.

14bi switching transistor 7a+7
Since sufficient base current is supplied to b, inverter 3
starts to operate, and an external current flows through the discharge lamp 4 as shown in FIG. In this way, dimming can be performed by controlling the conduction phase of the control transistor 13.

However, in these conventional discharge lamp dimming devices, for example, the device shown in FIG. 1 requires a large amperage element in a portion corresponding to the thyristor 5;
Not only does the device shown in FIG. 2 require a phase control device 6, but also the inverter 31r suddenly starts operating at a phase (θl of FIG. 2) corresponding to the degree of dimming, so the switching transistor of the inverter has There was also a risk that a high voltage would be suddenly applied during this operation start phase, leading to breakdown 4.

This invention was made in order to eliminate the above-mentioned drawbacks of the conventional art, and the pace i! which is supplied to the switching transistor of the inverter! By changing the size of
It is an object of the present invention to provide a dimming device for a discharge lamp which can perform dimming by changing the phase at which the discharge lamp resumes arc discharge.

Embodiments of the light control device for a discharge lamp according to the present invention will be described below with reference to the drawings. FIG. 4 is a circuit diagram showing the configuration of one embodiment. In this FIG. 4 V, the same parts as in FIG.
I will briefly describe the parts that are different from the figure.As is clear from the comparison with all of Figure 4 and Figure 3, in Figure 4, the base 1h, the sinus (ljl path 12), the control The base of the transistor 130 is connected to the connection point between the resistor 15 and the variable resistor 1G.The parallel circuit of the resistor 15 and the variable resistor 1G is connected between the positive and negative output terminals of the full-wave rectifier w2. The rest of the structure is exactly the same as that shown in FIG.

Next, the operation of the discharge lamp dimmer device of the present invention configured as described above will be explained. First, when a DC voltage as shown in FIG. 1 (A) is applied to the inverter 3, the inverter starts oscillating, a high frequency voltage is generated in the secondary winding 8S of the output transformer 80, and is applied to the discharge lamp 4. This is similar to the discharge lamp lighting device shown in FIG.

Here, the output voltage of the control transistor 13 of the base power supply circuit 12 is changed by the variable resistor 16.

The output type JIE of the control transistor 13 is shown in Figure 5 (
If the value is as shown in E2 of b), the base is sufficiently large.
Since the current flows through the resistors 14a and 14b to the switching transistors 7a and 7b, the rlf current 4 is released.
As shown in FIG. 5(b), the current flowing through the arc discharges at a phase θ2 relative to the power supply voltage.

Here, the reason why no current flows during the period from 00 to θ2 is because the output DC voltage of the full-wave rectifier 2 is low, similar to the explanation of the discharge lamp dimming device in Fig. 21'71. Volume 2+! This is because the voltage of 11ss has not risen to a voltage sufficient to restart the discharge lamp 4.

Next, by adjusting the variable resistor 16, the control transistor 13
Suppose that the output voltage of is lowered as shown in E3 in FIG. 5(a). At this time, the base current value required for the switching transistors 7a and 7b of the inverter 3 to light the discharge lamp 4 in a normal arc discharge state is determined by the output voltage of the control transistor 13 being E in FIG. If the electric power requirement shown in Figure 5 is followed, the discharge lamp 4 will resume arc discharge after reaching the phase θ3 of Figure 5 0), so the current of the discharge lamp 4 will be as shown in Figure 5 e →. The arc emitted i1 near the phase θ3
'er starts, and in the period before that, even if the flashing starts, it is in a glow flashing state with a small current.

In the lighting state shown in FIG. 5(•), the luminous flux generated by the discharge lamp 4 is slightly smaller than in the case shown in FIG. 5←).

In this way, the output voltage of the control transistor 13 is changed to the output voltage waveform J of the full-wave rectifier 2: similar Kf.

The light can be adjusted by changing the brightness.

As the base ili source circuit 12, the following 1 shown in the embodiment is used.
However, the inverter 3 is not limited to the one shown in the embodiment as long as it can change the magnitude of the base current substantially corresponding to the change in the instantaneous value of the output DC voltage of the full-wave rectifier 2. , the discharge lamp can be lit at full high frequency, and the phase shift that causes the discharge lamp to enter the arc discharge state can be changed by controlling the base current values of the switching transistors 7a and 7b. It is possible to use 1.

As shown in the figure below, the discharge lamp dimmer of the present invention converts the voltage of an AC fit source into a high-frequency voltage using a pulsating R++ current voltage, which is full-wave rectified, using a voltage transformer.
T! 1 to 11 (lighting the lamp, changing the base current of the switching transistor of this transistor inverter approximately in correspondence with the change in the instantaneous value of the DC voltage, and repeating the arcing for each half cycle of the AC power supply) Since the dimming is performed by changing the starting position at @, it is possible to perform good dimming with a relatively simple configuration, and it also reduces inverter failure and improves the reliability of the device. can.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a conventional discharge lamp dimmer, and FIGS. 2(a) to 2(b) are waveform diagrams for explaining the operation of the discharge lamp dimmer of FIG. FIG. 3 is a circuit diagram of another conventional discharge lamp dimming device, FIG. 4 is a circuit diagram showing an embodiment of the discharge lamp dimming device of the present invention, and FIGS.
The figure (•) is a waveform diagram for explaining the operation of the discharge lamp dimming device of the present invention shown in FIG. 4. 1... AC power supply, 2... Full wave rectifier, 3... Transistor inverter, 4... 271 lights, 7 & 17b
...Switching transistor, 8...Output transformer, 9...High frequency choke coil, 10...Capacitor, 11...Choke coil, 12...Base'
MkI+1 path, 13... control transistor, 14 a
y 14 b + 15...Resistance, 16...Variable resistance. In addition, the same reference numerals in the drawings indicate all the same or similar parts. Agent Makoto Kuzuno - Procedural amendment defense (voluntary) 11 summons (157 April 1] 12 item 1,, y Director-General IJ (〉 1, 'lf display ↑, 1 - 1977-1)
No. 36576 2, Name of the invention (4, Discharge lamp dimmer 3, Amendment made by a talented person. 1 Relationship with the work Patent amount 1. Claims column of the subject specification. 6. Contents of the amendment as shown in the attached sheet. 7. List of attached documents Revised claims 1 copy Claims A pulsating AC phase 1 source voltage obtained by full-wave rectification DC voltage,
A transistor inverter includes a switching transistor, which converts it into a high-frequency voltage to light the discharge lamp, supplies a base 1L current to the pace of the switching transistor, and converts this base frost and current value into a change in the instantaneous value of the DC voltage. and a base power source for dimming by changing the phase in which the discharge lamp starts arcing repeatedly for each half cycle of the AC power source by changing the magnitude of the pace current and changing the magnitude of the pace current. A discharge lamp dimmer comprising a circuit.

Claims (1)

[Claims] The pulsating DC voltage obtained by full-wave rectification of the voltage of the AC power supply is converted into high-frequency voltage to light the discharge lamp, and the transistor inverter is mainly composed of switching transistors, and a pace current is supplied to the base of this switching transistor. K, the value of this pace current is changed approximately corresponding to the change in the instantaneous value of said DC voltage, and the magnitude of this pace @ current is varied, K, so that the discharge lamp repeats the arc for each half cycle of said AC power supply. A dimmer device for a discharge lamp, comprising a base power supply circuit that performs dimming by changing the phase at which full discharge starts.