JP2584025B2 - Discharge lamp lighting device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a discharge lamp lighting device for lighting a discharge lamp at high frequency.

2. Description of the Related Art In general, in this type of apparatus, an electric shock may be generated from a discharge lamp when the discharge lamp is replaced. As a device for preventing such an electric shock, there is a device using an insulating transformer as shown in FIG.

That is, a rectifier circuit 3 indicated as RE is connected to the power supply 1 via a noise preventing common mode yoke 2 indicated as BNT _1, and a smoothing capacitor 4 is connected to the rectifier circuit 3.
(C ₁ ) is connected.

Here, the common mode yoke refers to one that effectively operates with respect to currents flowing simultaneously from both ends of the power supply, and has a structure in which one end of the power supply is connected to a lighting device through a winding, and The other end is also connected to the lighting device through a winding. These two windings are magnetically coupled by a ferrite core,
Further, the winding is wound so as to be a difference winding. Therefore, no inductance is generated for a current flowing from one end of the power supply and flowing out of the other end, and the current does not function as a current limiting chiyoke. However, an inductance is generated with respect to a current flowing simultaneously from both ends of the power supply, and a large impedance is generated with respect to the electric shock current, so that only the electric current is reduced.

Then, in the smoothing capacitor 4, Q ₁ and Q ₂ and displayed transistors 5 and 6 and C ₂ and C ₃ and the capacitor 7 and 8 displayed the lighting circuit is connected to the lighting device having the configuration Have been. The discharge lamp 10 and the capacitor 11 (C ₄ ) are connected to such a lighting device via an insulating transformer 9 indicated by T.

In the case of using the insulating transformer 9 as described above,
Due to the presence of the insulating transformer 9, the electric shock current
⇒Human ⇒Ground ⇒Power 1 ⇒Lighting device ⇒Discharge lamp 10 is prevented from flowing to prevent human beings from receiving electric shock.

On the other hand, as a discharge lamp lighting device, a direct power supply type using a half bridge circuit is often used. In this type, there is no effective countermeasure against the electric shock current, and in this type, the countermeasure against the electric shock is currently neglected.

Problems to be Solved by the Invention In the case of using an insulating transformer, the insulating transformer is structurally large and expensive,
In addition, there is a problem that loss due to conversion efficiency is large, temperature rise is high, and reliability is lacking. For this reason, it is desirable to use the above-described discharge lamp lighting device of the direct power supply type, but since this type does not take measures against electric shock, the electric current from the discharge lamp is large and the discharge current is large. There is a problem that the user is electrically shocked when replacing the lamp, which is dangerous.

Means for Solving the Problems In a discharge lamp lighting device of a power supply direct connection type, a common mode tie yoke for preventing noise and a common mode tie yoke for preventing electric shock current are provided in series on the power supply side.

Further, a discharge lamp lighting device of a half-bridge type directly connected to a power supply was used, and a lamp current limiting current yoke coil was wound around both ends of the discharge lamp.

Furthermore, a lamp current limiting current limiting yoke coil is dividedly wound around both ends of the discharge lamp so that the inductance value becomes 1: 1.
In addition, a capacitor was connected in parallel with the common mode yoke for preventing electric shock current.

Here, the common mode is a term in comparison with the normal mode, and the “common mode” refers to a state in which the potential between the grounds of each part of the circuit fluctuates simultaneously, and the “normal mode” refers to the state of each part of the circuit. This refers to a state in which the potential between grounds fluctuates relatively.

The lightning current from the discharge lamp is similar to the common mode noise, and the common mode tie yoke for preventing the lightning current connected in series with the common mode tie yoke for preventing the noise is effective. And electric shock due to electric shock is effectively prevented even in a discharge lamp lighting device of a power supply direct connection type.

Further, since the lamp current limiting current limiting yoke coil is dividedly wound at both ends of the discharge lamp, the lamp current limiting current limiting yoke coil is provided with the function of a common mode filter, so that the electric shock current can be reduced more effectively.

Furthermore, the current-carrying current limiting coil is wound around both ends of the discharge lamp so that the inductance value becomes 1: 1 to improve the waveform of the lightning current, and a filter for the waveform is provided with a common mode chip for preventing the lightning current. It was formed by a capacitor connected in parallel with the yoke.

Embodiment A first embodiment of the present invention will be described with reference to FIG.
The same parts as those described with reference to FIG. 5 are denoted by the same reference numerals, and description thereof will be omitted.

First, the power source 1 side of the lighting device, i.e., between the common-mode switch yoke 2 and the rectifier circuit 3 for preventing noise, common mode switch yoke 12 for high shock current prevention of impedance at the common mode of displaying the BNT ₂ Is connected. The connection point between the emitter of the transistor 5 and the collector of the transistor 6 is connected to the capacitors 7,8.
Discharge lamp with a capacitor 11 connected between
10 and a lamp current limiting current limiting yoke coil 13 are connected in series.

In such a configuration, the description of the lighting operation of the discharge lamp 10 is omitted, but when the power is turned on, the discharge lamp 10
When touching the hand to replace the
⇒ Human ⇒ Grounding ⇒ Power supply 1 ⇒ Lighting device input ⇒ Lighting device ⇒ Discharge lamp 10 tries to flow. However, since the common-mode yoke 12 for preventing a lightning current in the common mode and having a high impedance is inserted into the lighting device input, the circuit impedance of the lightning current in the above-described path is increased and the current is reduced. Therefore, there is no electric shock when touching the discharge lamp 10, and safety is enhanced.

When the insulating transformer 9 shown in FIG. 5 is compared with the common-mode yoke 12 for preventing electric shock current according to the present embodiment, the size thereof is considerably different. The common mode choke 12 for preventing electric shock current is less than half of the insulating transformer 9 shown in FIG. Therefore, since the insulating transformer 9 is not used, even if a new common-mode yoke 12 for preventing electric shock current is required, the overall size and weight are reduced.

Next, a second embodiment of the present invention will be described with reference to FIG. The same parts as those in the above embodiment are denoted by the same reference numerals, and the description is omitted. This embodiment, the lamp current limit diverted Chiyokukoiru 13 and shunt winding 14, 15 of the L ₁ and L _2, in which is disposed at both ends of the discharge lamp 10.

In such a configuration, the lamp current limiting current limiting yoke coil 13 including the shunt windings 14 and 15 is connected to the discharge lamp 10 ⇒ human ⇒
When viewed from the lightning current circuit of the grounding ⇒ power supply 1 ⇒ lighting device input ⇒ lighting device ⇒ discharge lamp 10, it acts as a common mode yoke, and as seen from the lamp current circuit, acts as a no multi-yoke coil. Therefore, the electric shock current can be kept low without adding any components and without increasing the size of the chiyoke coils.

Further, a third embodiment of the present invention will be described with reference to FIG. The same parts as those in the above embodiments are denoted by the same reference numerals, and description thereof is omitted. In this embodiment, the impedance values of the shunt windings 14 and 15 of the lamp current limiting current limiting yoke coil 13 are set to 1: 1.
In addition, capacitors 16 and 17 labeled C ₅ and C ₆ are connected in parallel to the common mode yoke 12 for preventing electric shock current.

In such a configuration, since the impedance values of the shunt windings 14 and 15 of the lamp current limiting current limiting yoke coil 13 are set to 1: 1, generally, harmonics as shown in FIG. As shown in FIG. 4 (b), the distorted waveform of the contained electric shock current is close to the lighting frequency with less distortion (a waveform having relatively few harmonics and a large fundamental wave component).
And

On the power supply 1 side, since the capacitors 16 and 17 are respectively connected in parallel to the common mode yoke 12 for preventing electric shock current, an LC parallel resonance circuit is formed. Since only the fundamental wave shown in FIG. 7B is cut, the electric shock current is efficiently cut.

Therefore, a common-mode yoke for preventing electric shock current
The lamp device 12 and the lamp current limiting current limiting yoke coil 13 may be small, and an inexpensive lighting device with small electric shock current can be obtained.

In the implementation, capacitors 16 and 1 indicated as C ₅ and C ₆ are connected in parallel with the common mode yoke 12 for preventing electric shock current.
7 may be connected to only one side.

Advantageous Effects of the Invention As described above, the present invention provides a discharge lamp lighting device of a power supply direct connection type, in which a common mode tie yoke for preventing noise and a common mode tie yoke for preventing electric shock current are provided in series with each other on the power supply side. Therefore, the electric shock current from the discharge lamp is
Utilizing the similarity to the common mode noise, the common mode chiyoke for preventing noise, which is connected in series with the common mode chiyoke for noise reduction, effectively reduces the electric shock current, and the direct current type Electric lamps can also effectively prevent electric shocks due to electric shock.In addition, a half-bridge type discharge lamp lighting device of a direct power supply type is used. By providing the current limiting current limiting yoke coil with the function of a common mode filter, the electric shock current can be more effectively reduced. In addition, a lamp current limiting current limiting yoke coil was wound around both ends of the discharge lamp so that the inductance value became 1: 1. This has the effect of improving the waveform of the current and forming a filter for the waveform by a capacitor connected in parallel with the common mode yoke for preventing electric shock current.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a first embodiment of the present invention, FIG. 2 is a circuit diagram showing a second embodiment of the present invention, and FIG. 3 is a circuit diagram showing a third embodiment of the present invention. 4 (a) and 4 (b) are waveform diagrams showing a waveform of an electric shock current before shaping and a waveform of an electric shock current after shaping, and FIG. 5 is a circuit diagram showing an example of a conventional device. DESCRIPTION OF SYMBOLS 1 ... Power supply 2 ... Common mode chiyoke for noise prevention, 10 ... Discharge lamp, 12 ... Common mode chiyoke for electric shock current prevention, 13 ... Chiyoke coil for lamp current limiting current,
16,17 …… Capacitor

Claims (3)

(57) [Claims] In a discharge lamp lighting device of a power supply direct connection type,
A discharge lamp lighting device characterized in that a common mode yoke for preventing noise and a common mode yoke for preventing electric shock current are connected in series with each other on a power supply side. 2. A discharge lamp lighting device of a half-bridge type which is directly connected to a power supply, wherein a common-mode yoke for preventing noise and a common-mode yoke for preventing electric shock current are provided in series with each other on a power supply side, and a lamp current is provided. A discharge lamp lighting device, wherein a current limiting chiyoke coil is provided by being wound around both ends of a discharge lamp. 3. A discharge lamp lighting device of a half-bridge type which is directly connected to a power supply, wherein a common-mode yoke for preventing noise and a common-mode yoke for preventing electric shock current are provided in series on the power supply side, and a lamp current is provided. A discharge lamp lighting device, characterized in that a current limiting chiyoke coil is provided at both ends of a discharge lamp by winding with a 1: 1 inductance value, and a capacitor is connected in parallel with the common mode chiyoke for preventing electric shock current.