JP2691427B2 - Discharge lamp lighting device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an improvement in a circuit for increasing a pulse voltage generated from a starter circuit unit for applying a starting pulse voltage to a discharge lamp of a discharge lamp lighting device.

[Prior Art] The circuit of FIG. 2 has been conventionally known as a high-frequency lighting type discharge lamp lighting device.

In FIG. 2, the AC power source 10 is connected to the inverter circuit unit 14 via the DC power source unit 12 and the choke coil L _1, and the phase advancing capacitor is connected from the secondary side of the inverter circuit unit 14.
The discharge lamp 16 is connected via C ₂ and the choke coil L ₂ . Further, a starter circuit unit 18 is connected in parallel to the discharge lamp 16.

Here, the inverter circuit unit 14 includes switching transistors Q ₁ and Q ₂ , an oscillation transformer T ₁ , an oscillation capacitor C ₁
It is a constant-current push-pull inverter circuit composed of base resistors R ₁ and R ₂ .

Further, the starter circuit 18, a series circuit of SIDAC S _D and SIDAC S _D capacitor C _S for breakover of a bidirectional two-terminal thyristor in a predetermined position and one end of the choke coil L ₂ (the discharge lamp 16 side) Are connected in parallel. Further, the SIDAC S _D and the diode D _S in the reverse direction (SIDAC side cathode) to the connection point between the capacitor C _S
And the charging circuit of the resistor R _S is connected.

To explain the operation of such a circuit, first, the AC power supply
The DC power supply unit 12 converts the DC voltage into a DC voltage V _D , the inverter circuit unit 14 oscillates the DC voltage V _D at a predetermined frequency, and the high frequency voltage is output from the secondary side of the oscillating transformer T ₁ . The output voltage of this oscillation transformer T ₁ is generally It is represented by Therefore, a half wave charges the capacitor C _S via the resistor R _S and the diode D _S of the starter circuit unit 18 and charges the phase advance capacitor C ₂ via the choke coil L ₂ . While repeating this, when the charging voltage of the capacitor C _S rises and reaches the breakover voltage of the sidac S _D , the capacitor C _S discharges and starts to the discharge lamp 16 by LC oscillation via the sidac S _D and the choke coil L _2. A pulse voltage is applied and it is made to act repeatedly until the discharge lamp lights up.

The circuit of the above discharge lamp lighting device is generally used because it is simple and inexpensive.

[Problems to be Solved by the Invention] By the way, it is desirable that the applied voltage is high in order to reliably start and light the discharge lamp. Generally, the height of the starting pulse voltage generated by the starter circuit unit 18 is mainly determined by a part of the choke coil L ₂ of the starter circuit unit 18 (0 to 0 in the figure).
The number of turns of 1) and the total number of turns of the choke coil L ₂ (0 in the figure)
2) the ratio of, and is determined by the breakover voltage of SIDAC S _D is a bidirectional two-terminal thyristor,
The high frequency lighting type choke coil L ₂ must have a small number of turns in order to obtain the impedance required for operating at high frequencies. On the other hand, in order to increase the number of turns for pulse generation, the number of turns of the choke coil L ₂ of 0 to 1 may be reduced, but the inrush current from the capacitor C _S is controlled when the sidac S _D breaks over. Therefore, the number of turns of 0 to 1 of the choke coil L ₂ cannot be reduced below a certain level. Further, the number of turns of the choke coil L ₂ can not be taken excessively large number of turns to the choke coil L ₂ also serves as the current controlling inductance of the discharge lamp 16. Therefore, in order to increase the starting pulse voltage, it is effective to increase the breakover voltage of SIDAC S _D.

However, the voltage applied to Sidac S _D is
It is determined by the secondary voltage of the oscillation transformer T ₁ a terminal voltage of the C _S, the secondary voltage of the oscillation transformer T ₁ denotes a DC power supply unit
There is a problem in that the voltage cannot be raised above a certain value because it is restricted by the voltage V _{D of} 12 and the rating of the discharge lamp 16.

Therefore, the present invention has been made in view of the above problems, and an oscillation transformer having a higher starting pulse voltage is provided by separately providing a winding portion for increasing the terminal voltage of a capacitor for generating a starting pulse of a starter circuit. It is intended to provide an electric lighting device.

[Means for Solving the Problems] In order to solve the above problems, the present invention provides another winding portion in an oscillation transformer to increase the terminal voltage of a capacitor for generating a starting pulse, and thereby the capacitor is provided in the capacitor. It focuses on charging.

That is, the discharge lamp lighting device of the present invention is a DC power supply unit,
An inverter circuit unit having an oscillating transformer, a choke coil, a starter circuit unit including a charging circuit for charging a capacitor for generating a starting pulse, and a discharge lamp. It has a winding part and a second winding part, the first winding part is connected to the discharge lamp, and the second winding part is connected to the charging circuit of the starter circuit part.

[Operation] In the discharge lamp lighting device of the present invention, the oscillation transformer of the inverter circuit section is separately provided with the second winding section for charging the capacitor for generating the starting pulse of the starter circuit section.
This second winding has a higher output voltage than the first winding,
The capacitor for starting pulse is charged with a high voltage through the charging circuit of the starter circuit section. Here, in the starter circuit unit, for example, a bidirectional two-terminal thyristor having a high breakover voltage is connected in series with a capacitor for generating a starting pulse, and the charging voltage of the capacitor becomes the breakover voltage of the thyristor. When reaching, the pulse voltage is applied to the discharge lamp. As a result, the terminal voltage of the capacitor can be increased, and by extension, the voltage of the starting pulse applied to both ends of the discharge lamp can be increased to ensure the starting lighting.

EXAMPLES Hereinafter, preferred examples of the present invention will be described with reference to the drawings.

FIG. 1 is a circuit diagram showing a discharge lamp lighting device of the present invention. In FIG. 1, an AC power supply 110 is connected to an inverter circuit section 114 via a DC power supply section 112 and a choke coil L _1, and a phase advancing capacitor C ₂ and a choke coil L ₂ are connected from the secondary side of the inverter circuit section 114. Through discharge lamp 116
Is connected. A starter circuit unit 118 is connected in parallel to the discharge lamp 116.

Here, the starter circuit 118, a part of the discharge lamp 116 side of the choke coil L _2, connected in parallel a series circuit of capacitor C _S to generate a starting pulse to breakover the SIDAC S _D and the Sidac S _D It is a circuit. This Sidac S _D has a breakover voltage set higher than the conventional one. A charging circuit in which a diode D _S in the reverse direction (cathode on the side of the Sidac S _D ) and a resistor R _S for current control are connected in series is connected to the connection point between the sidac S _D and the capacitor C _S.

On the other hand, the inverter circuit unit 114 includes switching transistors Q ₁ and Q ₂ , an oscillation transformer T ₁ , an oscillation capacitor C ₁
It is a constant-current push-pull inverter circuit composed of base resistors R ₁ and R ₂ . Also, the oscillation transformer T ₁
Is extended from the first winding portion N ₁ and the first winding portion N ₁ ,
A second winding portion N ₂ having a high output voltage is provided,
The end of the winding portion N ₁ is connected to the discharge lamp 116, and the end of the second winding portion N ₂ is the charging circuit (resistor R _S ) of the starter circuit portion 118.
It is connected to the.

Next, the operation of the above circuit will be described. First, AC power supply 11
0 is converted into a DC voltage V _D by the DC power supply unit 112 and input to the primary side of the inverter circuit unit 114 via the choke coil L ₁ . The inverter circuit unit 114 oscillates at a predetermined frequency and is output from the secondary side.

First, in the first half-wave, the starter circuit section 118 from the second winding section N ₂ in the oscillation transformer T ₁ of the inverter circuit section 114.
The capacitor C _S for breakover of the sidac S _D is charged via the resistor R _S and the charging circuit of the diode D _S. This is repeated the terminal voltage of the capacitor C _S gradually rises, turning on the SIDAC S _D when increased to the breakover voltage of the SIDAC S _D. And
When the sidac S _{D is} turned on, the charge charged in the capacitor C _S is discharged through the sidac S _D and a part of the choke coil L ₂ , and the starting pulse voltage is discharged by the LC oscillation to the discharge lamp.
Apply to 116. Then, the above operation is repeated until the discharge lamp 116 is turned on.

That is, since the capacitor C _S of the starter circuit unit 118 is charged by the second winding unit N ₂ of the oscillation transformer T ₁ , the terminal voltage of the capacitor C _S is made higher than that of the conventional device shown in FIG. It is possible to obtain sufficient voltage to break over a sidac S _D having a high breakover voltage. Therefore, the pulse voltage applied to the choke coil L ₂ is increased, the starting pulse voltage applied to both ends of the discharge lamp 116 can be increased, and the start lighting of the discharge lamp 116 can be ensured.

[Effects of the Invention] As is apparent from the above embodiments, according to the present invention, the oscillation transformer of the inverter circuit section is provided with the second winding section to charge the capacitor for generating the starting pulse of the starter circuit section. It is possible to use a sidac with a high breakover voltage by increasing the terminal voltage of the capacitor without changing the turns ratio of the choke coil by connecting it to the charging circuit. By increasing the pulse voltage, it is possible to ensure the starting lighting of the discharge lamp.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a discharge lamp lighting device of the present invention, and FIG.
FIG. 1 is a circuit diagram showing a conventional discharge lamp lighting device. 112 ... DC power supply 114 ... inverter circuit unit 116 ... discharge lamp 118 ... starter circuit T ₁ ... oscillation transformer

 ─────────────────────────────────────────────────── --- Continuation of the front page (56) Reference JP-A-58-117690 (JP, A) JP-A-59-103319 (JP, A) JP-A-62-29096 (JP, A) JP-A-58- 128696 (JP, A) JP 58-128695 (JP, A) JP 59-160998 (JP, A)

Claims (1)

(57) [Claims] 1. A DC power supply unit connected to an AC power supply, an inverter circuit unit having an oscillation transformer for oscillating the output of the DC power supply unit, and a choke connected to the secondary side of the oscillation transformer of the inverter circuit unit. A coil, a starter circuit section having a part of the choke coil, including a capacitor for generating a starting pulse and a charging circuit for charging the capacitor, and a discharge lamp connected in parallel to the starter circuit section. In the electric lamp lighting device, the oscillation transformer of the inverter circuit section has a first winding section and a second winding section, the first winding section being connected to the discharge lamp, and the second winding section. The discharge lamp lighting device is characterized in that the section is connected to the charging circuit of the starter circuit section.