JPH10302984A - Lighting device for discharge lamp and lighting system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lighting device for a discharge lamp which can preheat properly and detect mounting of the discharge lamp. SOLUTION: A current flows to a primary winding Tr1a of a filament preheating transformer Tr1 and a voltage is induced in a secondary winding Tr1b, Tr1c, so that each filament FLa, FLb is preheated. Since a capacitor C4 is connected, a half wave is not made like the case of a diode, and the filament FLa is preheated properly by supplying an all wave to the filament FLa, so that it is prevented that a spot temperature does not rise or an emission condition becomes worsen. Since a closed circuit is not formed when a fluorescent lamp is not mounted, and the capacitor C4 cuts off a direct current component, an electric potential is not generated at a connection point of resistances R2, R3. A detection as to whether the fluorescent lamp is mounted or not is carried out for a longer time than a time constant determined by a resistance R1 and the capacitor C4 to prevent an error in detecting.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge lamp lighting device and a lighting device having a filament preheating transformer.

[0002]

2. Description of the Related Art Conventionally, a discharge lamp lighting device of this type includes a half-bridge type inverter circuit having a pair of switching elements connected to a DC power supply, and one of the switching elements is connected to a fluorescent lamp and the other is connected to a fluorescent lamp. An impedance element such as a resistor is connected between the switching element and the filament of the fluorescent lamp, and a mounting detection circuit is provided at both ends of the DC power supply via the resistor. A primary winding of a filament preheating transformer is connected to the inverter circuit, a secondary winding of the filament preheating transformer is connected to each filament, and a circuit is formed between both ends of the DC power supply by a mounting detection circuit. Are connected in series to the secondary winding.

When the fluorescent lamp is not connected, since the filament is not mounted, the mounting detection circuit detects that no closed circuit is formed through the resistor, and determines that the fluorescent lamp is not mounted. Has been detected.

[0004]

However, if a diode is connected to the secondary winding of the filament preheating transformer, only a half-wave current flows through the filament to which the diode is connected, and the spot temperature cannot be maintained and There is a problem that the emission state deteriorates and proper preheating cannot be performed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a discharge lamp lighting device and an illuminating device capable of appropriately preheating and detecting installation of a discharge lamp.

[0006]

According to a first aspect of the present invention, there is provided a discharge lamp lighting device for converting a voltage of a DC power supply to turn on a discharge lamp having a filament; and one end connected to the DC power supply. An impedance element; a mounting detection circuit connected between both ends of the DC power supply via at least one of the filament of the impedance element and the discharge lamp lighting circuit; and 1 having a primary winding and a secondary winding.
A filament preheating transformer having a secondary winding connected to a discharge lamp lighting circuit; and a capacitor connected to a filament on a side serving as a path to a mounting detection circuit via a secondary winding of the filament preheating transformer. It is. The mounting detection circuit is connected to the DC power supply via at least one of the filament of the impedance element and the discharge lamp, and detects that the discharge lamp is not mounted and the filament is open. By pre-heating the filament, the DC component is cut by the condenser.

A discharge lamp lighting device according to a second aspect of the present invention is the discharge lamp lighting device according to the first aspect, further comprising a resonance circuit having a resonance inductor and a resonance capacitor for resonating the discharge lamp lighting device, and a filament preheating transformer. Is
The primary winding is composed of a current transformer and is connected in series to the resonance capacitor. And, by using a current transformer, the voltage induced in the secondary winding changes based on the product of the lamp voltage and the frequency of the discharge lamp lighting device. Therefore, regardless of the state of the discharge lamp, the filament is always preheated. I can do it properly.

A discharge lamp lighting device according to a third aspect of the present invention is the discharge lamp lighting device according to the second aspect, further comprising a phase adjusting capacitor connected in parallel to the primary winding of the filament preheating transformer. is there. The discharge lamp is appropriately lit by adjusting the phase difference between the lamp voltage of the discharge lamp and the voltage applied to the filament by the phase adjusting capacitor.

According to a fourth aspect of the present invention, there is provided the discharge lamp lighting device according to any one of the first to third aspects, wherein the mounting detection circuit detects mounting of the discharge lamp in a time longer than a time constant of the impedance element and the capacitor. It detects the presence or absence. By detecting the time longer than the time constant of the impedance element and the capacitor, erroneous detection due to the influence of the impedance element and the capacitor is prevented.

According to a fifth aspect of the present invention, there is provided a lighting device including the discharge lamp lighting device according to any one of the first to fourth aspects, and a fixture body provided with the discharge lamp lighting device. And since it has the discharge lamp lighting device of any one of Claim 1 thru | or 4, each effect | action is produced.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a lighting device according to an embodiment of the present invention.

FIG. 1 is a circuit diagram showing a discharge lamp lighting device, and FIG.
Is a perspective view showing the appearance of the lighting device, as shown in FIG.
A reflecting surface 2 is formed on the lower surface of the lighting fixture body 1, and lamp sockets 3 and 3 are mounted on both ends of the reflecting surface 2, and a fluorescent lamp FL as a discharge lamp is mounted between the lamp sockets 3 and 3. The discharge lamp lighting device 4 shown in FIG. 1 is housed inside.

In the discharge lamp lighting device 4, an inverter circuit 11 as a discharge lamp lighting circuit is connected to a DC power supply E, and the inverter circuit 11 has a transistor Q1 and a transistor Q2 as switching elements connected in series. In a half-bridge type, a resonance circuit 12 of a series circuit of a resonance inductor L1 and a resonance capacitor C1 is connected in parallel with a transistor Q2, and a DC cut capacitor C2 is connected in parallel with the resonance capacitor C1. The other ends of the filament FLa and the filament FLb of the fluorescent lamp FL are connected. The primary winding of the filament preheating transformer Tr1 is connected in parallel with the resonance capacitor C1.
A series circuit of Tr1a and capacitor C3 is connected.

A series circuit of a secondary winding Tr1b of the filament preheating transformer Tr1 and a capacitor C4 is connected between both ends of the filament FLa, and a secondary winding Tr1c of the filament preheating transformer Tr1 is connected between both ends of the filament FLb.
Is connected.

The positive electrode of the DC power source E and the filament FL
a, a resistor R1 as an impedance element is connected between the other end of the capacitor C2 and a resistor R1 on the filament FLa side of the capacitor C2.
Mounting detection circuit 14 composed of a series circuit of R2 and resistor R3
Is connected.

Next, the operation of the above embodiment will be described.

First, the voltage of the DC power supply E is applied to the transistor Q1.
By turning on and off the transistor Q2 alternately, the voltage is converted to a high-frequency voltage, and the fluorescent lamp FL is turned on. Also, the primary winding Tr of the filament preheating transformer Tr1
A current flows in 1a, and a voltage is induced in the secondary windings Tr1b and Tr1c to preheat the respective filaments FLa and FLb. Note that since the capacitor C4 is connected instead of a diode, the half-wave does not occur as in a diode,
FLa is supplied with the full wave shown in FIG. 3 to appropriately preheat the filament FLa and prevent the spot temperature from rising,
It prevents the emission state from becoming worse.

When the fluorescent lamp FL is mounted, the filament FLa is mounted.
Positive electrode of DC power supply E, resistance R1, filament FLa, resistance R
2. A closed circuit of the resistor R3 and the negative electrode of the DC power supply E is formed,
A potential is generated at the connection point between the resistors R2 and R3. Therefore, the inverter circuit 11 outputs as usual.

When the fluorescent lamp FL is not mounted, the filament FLa is not mounted, so that the positive electrode of the DC power source E, the resistor R1, the filament FLa, the resistor R2,
Since the closed circuit of the resistor R3 and the negative electrode of the DC power supply E is not formed, and the capacitor C4 cuts the DC component, no potential is generated at the connection point between the resistor R2 and the resistor R3. Therefore, the output of the inverter circuit 11 stops. The presence or absence of the fluorescent lamp FL is detected for a time longer than a time constant set by the resistor R1 and the capacitor C4 in order to prevent erroneous detection.

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

FIG. 4 is a circuit diagram showing a discharge lamp lighting device according to another embodiment. The embodiment shown in FIG. 4 differs from the embodiment shown in FIG.
Is a current transformer and is connected in series to the resonance capacitor C1.

Thus, the filament preheating transformer CT
By using 1 as a current transformer, the inverter circuit 11
When dimming with the output of the
Increase the voltage of FLa and FLb. In other words, if the filament preheating transformer CT1 is a voltage-type transformer instead of a current transformer, the filament voltage will change only by the change in lamp voltage. In contrast, if the filament voltage is set to an appropriate value at the time of all light, the filament voltage becomes lower at the time of dimming, and the preheating becomes inappropriate. However, FIG.
As shown in the figure, by using the filament preheating transformer CT1 as a current transformer, the filament voltage is proportional to the product of the change of the lamp voltage and the change of the frequency, that is, the product of the voltage across the resonance capacitor C1 and the resonance frequency. The primary winding CT of the filament preheating transformer CT1
The current flowing through 1a changes, and the preheating of the filaments FLa and FLb becomes appropriate both in the case of full light and in the case of dimming.

Another embodiment will be described with reference to FIG.

FIG. 5 is a circuit diagram showing a discharge lamp lighting device according to another embodiment. The embodiment shown in FIG.
In the embodiment shown in FIG.
A phase adjusting capacitor C5 is connected in parallel with the primary winding CT1a of CT1.

Thus, the filament preheating transformer CT
1 By connecting a phase adjusting capacitor C5 in parallel with the primary winding CT1a, the phase of the lamp current or the lamp current and the filament voltage is prevented from being shifted by 90 °, and the fluorescent lamp FL flickers. This ensures that the lamp is turned on without causing the occurrence of light.

[0026]

According to the discharge lamp lighting device of the first aspect, the mounting detection circuit is connected to the DC power supply via at least one of the filament of the impedance element and the discharge lamp. By detecting that the filament is not mounted and the filament is open, and by cutting the DC component by a capacitor, the filament can be appropriately preheated.

According to the discharge lamp lighting device of the second aspect,
In addition to the discharge lamp lighting device according to claim 1, since the filament preheating transformer is a current transformer, the voltage induced in the secondary winding changes based on the product of the lamp voltage and the frequency of the discharge lamp lighting device. Regardless of the state of the discharge lamp, the filament can always be appropriately preheated.

According to the discharge lamp lighting device of the third aspect,
In addition to the discharge lamp lighting device according to the second aspect, the discharge lamp can be appropriately lit by adjusting the phase difference between the lamp voltage of the discharge lamp and the voltage applied to the filament by the phase adjusting capacitor.

According to the discharge lamp lighting device of the fourth aspect,
In addition to the discharge lamp lighting device according to any one of claims 1 to 3, by performing detection for a time longer than the time constant of the impedance element and the capacitor, erroneous detection due to the influence of the impedance element and the capacitor can be prevented.

According to the illuminating device of the fifth aspect, since there is provided the fixture main body provided with the discharge lamp lighting device of any one of the first to fourth aspects, each effect can be obtained.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing one embodiment of a discharge lamp lighting device of the present invention.

FIG. 2 is a perspective view showing an appearance of the lighting device.

FIG. 3 is a waveform diagram of a voltage for preheating the filament.

FIG. 4 is a circuit diagram showing a discharge lamp lighting device according to another embodiment of the present invention.

FIG. 5 is a circuit diagram showing a discharge lamp lighting device according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lighting fixture main body 4 Discharge lamp lighting device 11 Inverter circuit as discharge lamp lighting circuit 12 Resonance circuit 14 Mounting detection circuit C1 Resonance capacitor C4 Capacitor C5 Phase adjustment capacitor CT1, Tr1 Filament preheating transformer CT1a, Tr1a Primary winding E DC power supply FL Fluorescent lamp as discharge lamp FLa, FLb Filament L1 Inductor for resonance R1 Resistance Tr1b, Tr1c as impedance element Secondary winding

 ──────────────────────────────────────────────────の Continuing from the front page (72) Inventor Fuminori Nakaya 4-3-1 Higashishinagawa, Shinagawa-ku, Tokyo Toshiba Lighting & Technology Corporation

Claims (5)

[Claims] 1. A discharge lamp lighting circuit for lighting a discharge lamp having a filament by converting a voltage of a DC power supply; an impedance element having one end connected to the DC power supply; and at least one of the impedance element and the discharge lamp lighting circuit. A mounting detection circuit connected between both ends of a DC power supply via the filament; a filament preheating transformer having a primary winding and a secondary winding, the primary winding being connected to a discharge lamp lighting circuit; A discharge lamp lighting device, comprising: a capacitor connected to a filament on a side serving as a path to a mounting detection circuit via a secondary winding of the filament preheating transformer. 2. A resonance circuit comprising a resonance inductor and a resonance capacitor for resonating the discharge lamp lighting device, wherein the filament preheating transformer is constituted by a current transformer, and a primary winding is connected to the resonance capacitor. The discharge lamp lighting device according to claim 1, wherein the discharge lamp lighting device is connected in series. 3. The discharge lamp lighting device according to claim 2, further comprising a phase adjusting capacitor connected in parallel to a primary winding of the filament preheating transformer. 4. The mounting detection circuit detects the presence or absence of the mounting of the discharge lamp for a time longer than the time constant of the impedance element and the capacitor.
The discharge lamp lighting device according to any one of the above. 5. A discharge lamp lighting device according to any one of claims 1 to 4, and an appliance body provided with the discharge lamp lighting device;
A lighting device, comprising: