JPH031491A - Pulse generator circuit of discharge lamp lighting device - Google Patents

Abstract

PURPOSE:To suppress the rush current by connecting an inductor in series to a capacitor and a switching element, which are connected in series to a pulse winding. CONSTITUTION:To start a discharge lamp 4, an aux. switching element 15 is turned on by electric charges accumulated in a capacitor 14 at every half a cycle of the power supply 1. Now a switching element 10 is turned on to cause electric charges accumulated a capacitor 8 to be discharged to a series circuitry composed of an inductor 16, element 10, capacitor 7, and pulse winding 2. Now a pulse voltage is induced in this winding 2 and boosted according to the ratio of turns of a choke coil 3 to the winding 2, and a high voltage pulse is generated to cause lighting-up of the discharge lamp 4. The rush current when the element 10 is turned on is suppressed by the inductor 16, and a steeper rush current enlarges the suppressing force of the inductor 16. Thereby the rush current can be satisfactorily braked by the inductor 16.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a discharge lamp lighting device having a pulse generation circuit for assisting in starting, for example, a discharge lamp.

(Prior art) As a conventional discharge lamp lighting device of this type, for example, a third discharge lamp lighting device is used.
The configuration shown in the figure is known.

In the conventional discharge lamp lighting device shown in FIG. 3, a choke coil 3 having a pulse generating winding 2 and a discharge lamp 4 are connected in series to a commercial AC power source 1. In addition, a capacitor 6 having a resistor 5 in parallel is connected between the input terminals.
A power factor correction capacitor 7 composed of is connected. A capacitor 8, a resistor 9, and a triac 10 are connected in series between the end of the pulse winding 2 on the center side of the choke coil 3 and the input end on the other end and the connection point of the discharge lamp 4. , the gate of this triac 10 has
A gate circuit 11 is connected. This gate circuit 11
In this case, two series-connected voltage dividing resistors 12 and 13 are connected in parallel to the discharge lamp 4, a charging capacitor 14 is connected in parallel to the voltage dividing resistor 13, and the voltage dividing resistor 1
One end of ssssts is connected to the connection point 2.13, and the other end of this SSS 15 is connected to the gate of the triac 10.

The discharge lamp lighting device shown in FIG.
When the discharge lamp 4 is started, the discharge lamp 4 is not lit.
The voltage between the terminals of is high. Therefore, the capacitor 14 is charged via the resistor 12, and S
S S +5 is turned on, a gate voltage is applied to the triac 10, and the triac 10 is turned on. As a result, the electric charge stored in the capacitor 8 is transferred to the pulse winding 2.
, the power factor correction capacitor 7, the triac 10, and the resistor 9. Then, a pulse voltage is induced in the pulse winding 2, and the voltage is increased according to the turn ratio between the choke coil 3 and the pulse winding 2, and a high voltage pulse is generated and applied to the discharge lamp 4. Then, by repeating the above operation, a high voltage pulse is generated every half cycle, and the discharge lamp 4 is lit. When the discharge lamp 4 is turned on, the voltage across the discharge lamp 4 decreases, the voltage charged to the capacitor 14 decreases, and S
SS 15 is no longer turned on and triac 10
Since no gate voltage is applied to triac 1
0 is no longer turned on, the pulse is stopped, and the light is turned on at the normal voltage.

(Problem to be Solved by the Invention) In the case of the discharge lamp lighting device shown in FIG. 3 above, the peak value of the current flowing at the moment the triac 10 is turned on is
and the impedance of the pulse winding 2. In addition, in the case of a choke coil of 100 W or less, the impedance is relatively large, so the inrush current is small at several A, but in the case of a choke coil of 150 W or more, the impedance is small, so the inrush current ranges from 10 (A) to several 10 (A). A), and the steepness of the rise of the rush current is 50
(A/asec) and several hundred (:A/jsec), which poses a problem of destroying the triac 10.

On the other hand, since the impedance of the pulse winding 2 is determined by the turns ratio of the voltage rise of the choke coil 3, the impedance of the pulse winding 2 cannot be set arbitrarily.

In addition, if the resistance value of the resistor 9 is increased, the attenuation of the charging/discharging current due to LCR series resonance will be faster, making it impossible to obtain sufficient pulse energy, and if the current is attenuated by the resistor 9, energy consumption and heat generation will increase. 9
The problem is that the circuit becomes larger due to the larger size and heat dissipation.

The present invention has been made in view of the above problems, and provides a pulse generation circuit for a discharge lamp lighting device that can prevent destruction of switching elements due to rush current without increasing the size of the circuit and without generating heat. The purpose is to

[Structure of the invention]

(Means for Solving the Problems) The present invention provides a pulse generation circuit for a discharge lamp lighting device in which a capacitor and a switching element are connected in series to a pulse winding provided in a coil.
An inductor is connected in series with the capacitor and the switching element.

(Function) According to the present invention, when a switching element is turned on when a pulse is generated, when an inrush current flows through a series circuit of a pulse winding, a capacitor, and a switching element, the inrush current is suppressed by an inductor.

(Example) Hereinafter, an example of the discharge lamp lighting device of the present invention will be described with reference to FIG. Note that parts corresponding to the conventional example shown in FIG. 3 will be described with the same reference numerals.

This discharge lamp lighting device includes a choke coil 3 having a pulse winding 2 in series with a commercial AC power source 1, and a discharge lamp 4.
are connected in series, and a power factor correction capacitor 7 consisting of a capacitor 6 to which a resistor 5 is connected in parallel is connected between the input terminals.

A capacitor 8, an inductor 16, and a switching device are connected between the end of the pulse winding 2 on the step-up winding side near the center of the choke coil 3 and the input end on the other end and the connection point of the discharge lamp 4. Triacs 10 as elements are connected in series, and a gate circuit is connected to the gate of the triac 10.

In this gate circuit 11, two series-connected voltage dividing resistors 12 and 13 are connected in parallel to the discharge lamp 4, and a charging capacitor 14 is connected in parallel to the voltage dividing resistor 13. One end of the 5S315 is connected to the connection point of the voltage dividing resistor 12.13, and the other end of the SSS 15 is connected to the gate of the triac IO.

Next, the operation of the circuit shown in FIG. 1 will be explained.

First, when starting with the discharge lamp 4 turned off, the voltage across the discharge lamp 4 is sufficiently high, so sufficient charge is accumulated in the capacitor 14 to turn on the 5SS 15. S S S once every half cycle of commercial AC power supply 1
Turn on 15. When this 5S815 is turned on, a gate voltage is applied to the gate of the triac 10, and the triac 10 is turned on. This triac lO
When turned on, the charge accumulated in the capacitor 8 is transferred to the inductor 16, the triac 10, and the power factor correction capacitor 7.
is discharged to the series circuit of the pulse winding 2, a pulse voltage is induced in the pulse winding 2, and is boosted by the turns ratio of the choke coil 3 and the pulse winding 2, generating a high voltage pulse.
The voltage is applied to the discharge lamp 4 and repeated until the discharge lamp 4 lights up.

Furthermore, the inrush current flowing at the moment the triac 10 is turned on is suppressed by the inductor 16.

In other words, if the rush current is steep, L di
Since al becomes larger, the suppressing force becomes larger and sufficient braking can be performed.

Furthermore, the circuit resistance of the inductor 16 is generally 0.1 [Ω
] or less, it is sufficiently small that it has almost no effect on the attenuation of the current during resonance, and also hardly generates heat.

On the other hand, when the discharge lamp 4 is turned on, the voltage between both ends of the discharge lamp 4 decreases, so that sufficient charge is not accumulated in the capacitor 14, and the S S S 15 is not turned on.

Next, another embodiment will be described with reference to FIG.

The circuit shown in FIG. 2 includes a leakage transformer 24 as a coil having a first winding 22 having a pulse winding 21 and a second winding 23 in place of the choke coil 3 shown in FIG. This is what was used.

The second winding 2 of the pulse winding 21 is connected to one end of the commercial AC power supply 1.
3 side terminal is connected, and the other end of the second winding 23 is connected via a bypass capacitor 25 having a power factor correction function, and the other end of the commercial AC power supply 1 is connected to the second winding 23
and the other end of the discharge lamp 4.

Further, one end of the first winding 22 is connected to one end of the discharge lamp 4, the center side of the first winding 22 of the pulse winding 21 is connected to the capacitor 8, and the other end of the second winding 23 is connected to one end of the discharge lamp 4. It is connected to one end of the triac 10.

When the triac 10 is turned on, the charge accumulated in the capacitor 8 is transferred to the pulse winding 21, the bypass capacitor 25, the triac 10, and the inductor 16.
In this case, the inrush current is similarly damped by the inductor 16.

Further, in both the circuits shown in FIGS. 1 and 2, a resistor may be provided in series with the inductor 1G as in the conventional case.

Further, the switching element 10 is not limited to the triac, and instead of the triac, for example, a thyristor having antiparallel diodes may be used, and a trigger diode may be used instead of the 5S815.

〔Effect of the invention〕

According to the present invention, since the inductor is connected in series with the capacitor and the switching element connected in series with the pulse winding, the inrush current when the switching element is turned on can be suppressed by the inductor.
Breakdown of the switching element due to rush current can be prevented without increasing the size of the circuit and without generating heat.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of the discharge lamp lighting device of the present invention, FIG. 2 is a circuit diagram showing an embodiment of the same function, and FIG. 3 is a circuit diagram showing a conventional example. 2.21...Pulse winding, 3...Choke coil, 8...
- Capacitor, 10... Triac as a switching element, 16... Inductor, 24 - Glue cage transformer as a coil. Wataru Kanmei

Claims (1)

[Claims] (1) In a pulse generation circuit of a discharge lamp lighting device in which a capacitor and a switching element are connected in series to a pulse winding provided in a coil, an inductor is connected in series to the pulse winding, the capacitor, and the switching element. A pulse generation circuit for a discharge lamp lighting device, characterized in that a discharge lamp lighting device is connected to the pulse generation circuit.