JPS62229793A - Discharge lamp burner - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a discharge lamp lighting device that performs dimming.

[Prior Art] Conventionally, as an example of a discharge lamp lighting device d, as shown in FIG. A discharge lamp lighting device is known. In the figure, Dl is a rectifier that supplies a commercial alternating current to the inverter as a direct current power source, C1 is an electrolytic capacitor on the output side of Dl, and C2 and C3 are !1 Flow!!2 series capacitors between the output terminals of 1iD1, Ql, C2 is the main switching transistor, 1-a is the discharge lamp, C4 is 1
A capacitor connected between the filaments of a 1i lamp, Ll
is the current limiting choke coil, 02.03 is the transistor Q1
, C2 is a diode connected in parallel between the collector and emitter of C2, and C5 is a capacitor connected in parallel with one of the diodes D2.
1 is connected between the connection point of the emitter and collector of transistors Q+ and C2 and a current limiting choke coil 1, and its two large turns aN2 and N3 are connected to the base resistor FLR1, 112 of transistor Ql and C2 for driving.

In order to dim the conventional lighting Vtε using an inverter with the discharge lamp Lae load as described above, the rectifier D1
LC consisting of inductor L2 and capacitor C6 in the front stage of
Triac TR installed between the filter and the ACm source
etc. control! The light was controlled by phase control using a D element.

[Problems to be Solved by the Invention] As described above, the lighting device d in which the LC filter is provided in the front stage of the inverter cannot perform dimming by phase control satisfactorily.

Accordingly, the present invention provides a discharge lamp lighting system δ that allows for good dimming regardless of the presence or absence of a smoothing circuit at the front stage.

[Means for Solving the Problems] In order to solve the problems described in iyJ, the present invention provides
In an inverter circuit that lights a discharge lamp by driving the main switching transistor with T, two saturable CTs are used.
A common main winding, a secondary winding for driving the transistor, and a DC bias winding are wound around each iron core, and a variable DC bias power supply is connected to the DC bias winding to create a discharge lamp lighting device. It is composed of

[Effect J By adjusting the variable DC bias power supply mentioned above, the DC bias magnetic field applied to each iron core of the saturable CT by the DC bias winding changes, thereby adjusting the drive of each transistor by the secondary winding. The discharge lamp will be dimmed.

[Example] Examples of the present invention will be described below with reference to FIGS. 1 to 3. In Figure 1, Dl is a rectifier that rectifies commercial AC and becomes the DC tIi source for the inverter, C1 is an electrolytic capacitor on the output side of this rectifier BD1, and C2 and C3 share the voltage between the output terminals of rectifier D1. It is two series capacitors. Ql, C2 are main switching transistors, R1, R2 are their base resistances, the collector of transistor Q1 is connected to the positive side of rectifier D1, and the emitter of transistor Q2 is connected to the negative side of rectifier D1 through resistor R4. , and a resistor R is connected to the emitter of transistor Q1.
3 and connect it to the collector of transistor Q2 at point a.

La is a discharge lamp serving as a load, one filament of which is connected to point b, which is an intermediate connection point between the capacitors C2 and C3, and the other filament connected to current-limiting choke coil L1. C4 is a capacitor connected between the filament and the filament.

TI, T2 are two saturable CTs, Tc1, Tc
2 is each iron core. NO is a common main winding commonly wound around both iron cores TC1 and Tc2 of these two saturable CTs, one of which is connected to the current-limiting choke coil L1, and the other is connected to the current-limiting choke coil L1. It is connected to point a, which is the connection point between the emitters and collectors of the transistors Q1 and C2. Also, N12 is 2 of T1 of one saturable CT.
The secondary windings, N22, are the 12 secondary windings of the other saturable CT, and each secondary winding N12, N22 is connected to each transistor Ql.
, C2, and one secondary winding N12
connects its lead terminals e, f to the base side resistor R1 and emitter side resistor R3 of the transistor Q1, and the other secondary winding N22 connects its lead terminals 9, h to the base side resistor R1 of the transistor Q2. Resistor R2 and emitter side resistor R
4, thereby driving each transistor Q1, C2.

N13 is a DC bias winding wound around the iron core Te1 of one T1 of the saturable CT, N23 is a free current bias winding wound around the iron core C2 of the other T2 of the saturable CT, and El is the DC bias winding fiN13 of the saturable CT. El is a variable DC bias power supply connected to the DC bias winding N23. Note that each DC bias winding 1i1N
13, N23 winding direction is DC bias winding N13, the direction of the current of the load discharge lamp is the current shown by the solid line arrow when transistor Q1 is turned on! In a cycle where the current flows in one direction, lNlN13 is wound so that the magnetic flux is generated in the same direction as the magnetic flux generated in the common main line No, and for the other DC bias winding N23, the direction of the load discharge lamp current is In a cycle in which transistor Q2 is turned on and current I2 flows in the direction of the dotted arrow, the common main winding NO
winding N23 so that magnetic flux is generated in the same direction as the magnetic flux generated in
wind it. Further, the variable DC bias power supplies El and El have the same voltage, and are configured to be variable power supplies so that both are linked and can open the same amount of glm at the same time.

Naj3D2. C3 is a diode connected in parallel between the collectors and emitters of transistors Q1 and C2, C5 is a capacitor connected in parallel to diode D2, L2,
C6 is rectification 2! AC in front of D1? l! These are the inductor and capacitor of the LG filter installed between the source and the source.

The discharge lamp lighting device d using the inverter configured as described above has a common main winding N of the two saturable CTs TI and T2.
2 entourage aN1 due to the alternating Ti direct current 1,+2 flowing to O
2. Alternate drive voltages are generated at N22, and the main switching transistors Ql and C2 are alternately driven, whereby the discharge lamp 1a is lit at high frequency.

Also, to perform dimming, two saturable CTs T1 and T2 variable DC bias 11! T1 and T of the saturable CT are adjusted by adjusting El and E2 and using the DC bias windings N13 and N23.
Each iron core TC1, Tc2 of 2 is processed by adjusting the magnetic field of 6M'tlLt
The light of the discharge lamp 1a is adjusted by adjusting the drive of the transistors Ql and Q2 by the transistors Q1 and Q2.

In the embodiment shown in the second figure, each of the variable DC bias power supplies T1 and T2 of the saturable CT is connected to 61. This is an example in which one common variable DC bias 'IR source power source E is used instead of each being installed separately as in E2, and Fig. 1 and fin-n
Numbers indicate the same parts. This embodiment is also similar to the embodiment shown in the first drawing, one of the lead-out terminals C of the common primary winding NO.
is connected to the current-limiting choke coil Ll (shown in the first diagram) in series with the discharge lamp, and the lead terminal d is connected to the transistor Q.
1. 8 connection points between the emitter and collector of Q2 (first
(shown), and is also connected to the lead-out terminal e of the secondary winding N12.
1f, and the lead terminal q1h of N22 are connected to the transistor Q1. Connect to Q2 as a drive winding.

By adjusting this one variable DC bias power supply E, each DC bias winding lN13, N23 is adjusted to T1. By changing the DC bias magnetic field applied to each iron core Tel and Tc2 of T2, the drive of each transistor Q1 and C2 can be adjusted and dimmed.

The embodiment shown in the third figure is an embodiment in which instead of configuring the inverter as in the embodiment shown in the first figure, it is configured as a push-pull type inverter and T1 and T2 of the saturable CT are applied. The same reference numerals as those in FIG.
nf is a filament heating winding of the discharge lamp La, C1 is a capacitor, 13 is a current limiting choke coil, and saturable CT
The lead-out terminals c and d of the common main winding NO of T1 and T2 are the winding 1NO1 connected to the iron core TCO of the inverter transformer.
yA continues.

In this embodiment, even if +3 is applied, the current flowing through the common main winding NO of the saturable CT TI and T2 causes its secondary winding 1N12,
A drive voltage is alternately generated at N22, and the main switching transistors Q+ and C2 are alternately driven. Also, when dimming, the variable DC bias power supply E is adjusted so that each DC bias winding aN13, N23 is connected to each saturable CT. T of
Dimming is achieved by changing the DC bias magnetic field applied to each of the iron cores TC1 and Tc2 of I and -T2 and adjusting the drive of each transistor Q1 and C2.

[Effects of the Invention] As described above, the present invention uses each secondary winding of the two saturable CTs as a drive winding of the main switching transistor, and also provides a variable DC bias winding to control each saturable CT.
Since the drive of each transistor is adjusted by applying a DC bias magnetic field to T, good dimming can be achieved with a simple circuit configuration regardless of the presence or absence of a smoothing circuit.

10 Simple explanation of fins in the drawings Figures 1 to 3 are circuit diagrams of embodiments of the present invention;
FIG. 4 is a circuit diagram of a conventional example.

La: 11i electric light. Ql, C2: transistor.

TI, T2: saturable CT, TC1, Tc2: iron core.

NO=common common wire winding 12, N22: secondary winding.

N13, N23: DC bias W line.

E, El, E2: variable DC bias power supply.

Claims (1)

[Claims] A discharge lamp, two switching transistors, two saturable CTs each having a secondary winding for driving each transistor and a common main winding wound around each iron core, and a DC bias wound around each of the aforementioned iron cores. A discharge lamp lighting device comprising a winding and a variable DC bias power supply connected to each of the DC bias windings.