JPH10214693A - Discharge lamp lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a discharge lamp lighting device which is not subjected to large stress on an inverter means even when a discharge lamp is attached in its detachment condition. SOLUTION: When a fluorescent lamp FL is not attached in a state of throwing a commercial AC power source (e), a voltage is not induced in a secondary winding Tr2b of a transformer Tr2. Then, a capacitor C21 is not charged to bring a Zener diode ZD11 to an OFF state. A light-emitting diode LED11 does not generate light, and a phototransistor Q11 is turned off to stop the flow of a base current of a transistor Q15, which is turned off. A transistor Q12 is turned on to discharge a capacitor C15, and the capacitor C15 is not charged. When the fluorescent lamp FL is attached to operate a preheat initiation circuit 4, a transistor Q1 of an inverter circuit 2 is operated to oscillate after starting with the state wherein an output of the inverter circuit 2 is lowered, thereby preventing the transistor Q1 from being subjected to large stress.

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 in which the stress of an inverter means is reduced.

[0002]

2. Description of the Related Art As a conventional discharge lamp lighting device, for example, a configuration shown in FIG. 2 is known.

In the discharge lamp lighting device shown in FIG. 2, a full-wave rectifier circuit 1 is connected to a commercial AC power supply e. A capacitor C1 for smoothing is provided between the output terminals of the full-wave rectifier circuit 1.
Are connected, and an inverter circuit 2 as inverter means is connected.

The inverter circuit 2 includes a capacitor
In parallel with C1, a resonance capacitor C2 and a primary winding Tr1a of an inverter transformer Tr1 as an inductor are connected.

A series circuit of the collector and the emitter of the transistor Q1 as a switching element is connected to a parallel circuit of the capacitor C2 and the primary winding Tr1a of the inverter transformer Tr1, and the base of the transistor Q1 is connected to the full-wave rectifier circuit 1. A startup resistor R1 connected to the positive electrode is connected, and a reflux diode is connected between the collector and the emitter.
D1 is connected.

Further, filaments FLa and FLb of a fluorescent lamp FL as a discharge lamp are connected to a secondary winding Tr1b of the inverter transformer Tr1 via a detection winding CT1a of the current transformer CT1 and a capacitor C3 for cutting DC current. ing. Further, a starting capacitor C4 is connected to these filaments FLa and FLb.

The control winding of the current transformer CT1
The diodes D2, D3, and D4 are connected to the CT1b, and are connected to the base of the transistor Q1. A series circuit of a diode D6 and a resistor R2 is connected between the base and the emitter of the transistor Q1.

Also, a transistor via the control winding CT1b
A capacitor C5 and a series circuit of a capacitor C6 and a field effect transistor Q2 are connected in parallel between the base and the emitter of Q1.

Further, an output control circuit 3 as output control means is connected in parallel with the capacitor C1.
This output control circuit 3 includes a resistor R3
And a series circuit of a capacitor C7 and a series circuit of a resistor R4 and a capacitor C8 are connected in parallel.
A series circuit of a resistor R5 and a resistor R6 is connected in parallel to C8, a capacitor C9 is connected in parallel to the resistor R6, and a base of the transistor Q3 is connected to a connection point of the resistors R5 and R6. . The emitter of the transistor Q3 is connected to a connection point between the resistor R3 and the capacitor C7 via the resistor R7, and the collector is connected to the negative electrode of the full-wave rectifier circuit 1 via the resistors R8 and R9. Further, a capacitor C11 is connected in parallel with the resistors R8 and R9, and a connection point of the capacitor C11 and the resistor R8 is connected to the resistor R1.
1 is connected to the gate of the field effect transistor Q2. Further, a series circuit of a resistor R12 and a zener diode ZD1 is connected in parallel with the capacitor C7.

A preheating start circuit 4 is connected in parallel to the output control circuit 3 as preheating start means.
In the preheating start circuit 4, a series circuit of a resistor R15 and a capacitor C15 is connected in parallel with the capacitor C8, and a zener diode ZD2 is connected in parallel with the capacitor C15.
And a series circuit of a capacitor C16. Further, the connection point of the Zener diode ZD2 and the capacitor C16 is connected to the base of the transistor Q4, and a diode is connected between the collector and the emitter of the transistor Q4.
A series circuit of D7 and a resistor R16 is connected, and the collector is connected via a resistor R17 to a connection point of a resistor R4 and a capacitor C8. The base of the transistor Q5 is connected to the connection point of the diode D7 and the resistor R16, and the collector and the emitter of the transistor Q5 are connected to both ends of the Zener diode ZD1.

Next, the operation of the discharge lamp lighting device shown in FIG. 2 will be described.

First, when the power is turned on, full-wave rectification is performed by the full-wave rectifier circuit 1, and a pulsating current is applied to the capacitor C1. Then, the inverter circuit 2 performs switching control of the DC voltage supplied from the capacitor C1 at a high frequency of the transistor Q1, and the primary winding Tr1 of the inverter transformer Tr1.
The voltage resonated by the inductance of a and the capacitance of the capacitor C2 is induced in the secondary winding Tr1b, and the fluorescent lamp FL
Supplied to Then, the condenser C4 preheats the filaments FLa and FLb of the fluorescent lamp FL, and at the same time, the condenser C4
Is applied to the fluorescent lamp FL to start and turn on the fluorescent lamp FL.

During the period when the capacitor C15 reaches a predetermined voltage value, that is, during the period when the power is turned on and the filaments FLa and FLb of the fluorescent lamp FL are preheated, the Zener diode ZD2 is kept off, so that the transistor Q4 The base current is not supplied to the transistor Q5, and the off state is maintained.The base current is supplied to the transistor Q5, thereby bypassing the Zener diode ZD1 and bypassing the current between the emitter and the collector of the transistor Q3. No gate voltage is applied to the gate of
Since the transistor Q1 is driven only by the capacitance of the capacitor C5, which is not connected in parallel with the capacitor C6, the output of the inverter circuit 2 is in a low state, the oscillation frequency of the transistor Q1 is high, and the output of the inverter circuit 2 is in a low state. At this low output, the filament FLa of the fluorescent lamp FL
, FLb is preheated.

After a lapse of a predetermined time, the capacitor C1
5 is charged, the Zener diode ZD2 is turned on, so that the base current is supplied to the transistor Q4 and the transistor Q4 is turned on.By bypassing the base current of the transistor Q5, the transistor Q5 is turned off and the emitter of the transistor Q3 is turned off. Since a current corresponding to the capacitors C7 and C8 flows between the collectors according to the voltage value of the commercial AC power supply e, a gate voltage corresponding to the voltage of the commercial AC power supply e is applied to the gate of the field effect transistor Q2, and the field effect Since the resistance value between the drain and source voltages of the transistor Q2 changes and the capacitor C6 whose apparent capacitance is connected to the capacitor C5 is connected, the oscillation frequency of the transistor Q1 decreases and changes. And the fluorescent lamp FL is turned on, and the voltage of the commercial AC power supply e fluctuates. Almost a constant output.

[0015]

However, in the case of the discharge lamp lighting device shown in FIG.
After the battery is charged, the capacitor C15 is not discharged as long as the commercial AC power supply e is connected. Therefore, even if the fluorescent lamp FL is not mounted and the fluorescent lamp FL is mounted, the preheating start circuit 4 operates. However, since the transistor Q1 starts oscillating from a high output state, there is a problem that an excessive stress is applied to the transistor Q1.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above problems, and has as its object to provide a discharge lamp lighting device in which even if a fluorescent lamp is mounted in a non-mounted state, a large stress is not applied to the inverter means.

[0017]

A discharge lamp lighting device according to the present invention comprises a variable output inverter for starting and lighting a discharge lamp, an output control means for controlling the output of the inverter, and an output of the inverter. Preheating start means for setting the discharge lamp to be lower than when lit for a predetermined time at the time of starting; mounting detection means for detecting a mounting state of the discharge lamp; and detecting the non-mounting of the discharge lamp by the mounting detection means, the preheating start means. Reset means for resetting. Then, in a state where the discharge lamp is not mounted, the preheating start means is reset, and the output control means lowers the output of the inverter circuit by the preheat start means. However, the output of the inverter circuit does not become high from the beginning, and a large stress is not applied to the inverter circuit.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the discharge lamp lighting device according to the present invention will be described with reference to the drawings. The portions corresponding to the conventional example shown in FIG.

In the discharge lamp lighting device shown in FIG. 1, a full-wave rectifier circuit 1 is connected to a commercial AC power supply e. A capacitor C1 for smoothing is provided between the output terminals of the full-wave rectifier circuit 1.
Are connected, and an inverter circuit 2 as inverter means is connected.

The inverter circuit 2 includes a capacitor
In parallel with C1, a resonance capacitor C2 and a primary winding Tr1a of an inverter transformer Tr1 as an inductor are connected.

A series circuit of a collector and an emitter of a transistor Q1 as a switching element is connected to a parallel circuit of a capacitor C2 and a primary winding Tr1a of an inverter transformer Tr1, and a full-wave rectifier circuit 1 is connected to a base of the transistor Q1. A startup resistor R1 connected to the positive electrode is connected, and a reflux diode is connected between the collector and the emitter.
D1 is connected.

Further, the filaments FLa and FLb of the fluorescent lamp FL as a discharge lamp are connected to the secondary winding Tr1b of the inverter transformer Tr1 via the detection winding CT1a of the current transformer CT1 and the DC cut capacitor C3. ing. Further, a series circuit of a starting capacitor C4 and a mounting detecting circuit 5 as mounting detecting means is connected to these filaments FLa and FLb.

The mounting detection circuit 5 includes a capacitor
A primary winding Tr2a of a transformer Tr2 is connected in series with C4, an input terminal of the full-wave rectifier circuit 6 is connected to a secondary winding Tr2b of the transformer Tr2, and an output terminal of the full-wave rectifier circuit 6 is connected to the output terminal of the full-wave rectifier circuit 6. , A capacitor C21, a resistor R21, and a series circuit of a zener diode ZD11 and a light emitting diode LED11 are connected in parallel, and a phototransistor Q11 is photocoupled to the light emitting diode LED11.

The control winding CT1b of the current transformer CT1
Are connected to diodes D2, D3 and D4, and the transistor Q1
And a series circuit of a diode D6 and a resistor R2 is connected between the base and the emitter of the transistor Q1.

Also, a transistor via the control winding CT1b
A capacitor C5 and a series circuit of a capacitor C6 and a field effect transistor Q2 are connected in parallel between the base and the emitter of Q1.

Further, an output control circuit 3 as an output control means is connected in parallel with the capacitor C1.
This output control circuit 3 includes a resistor R3
And a series circuit of a capacitor C7 and a series circuit of a resistor R4 and a capacitor C8 are connected in parallel.
A series circuit of a resistor R5 and a resistor R6 is connected in parallel to C8, a capacitor C9 is connected in parallel to the resistor R6, and a base of the transistor Q3 is connected to a connection point of the resistors R5 and R6. . The emitter of the transistor Q3 is connected to a connection point between the resistor R3 and the capacitor C7 via the resistor R7, and the collector is connected to the negative electrode of the full-wave rectifier circuit 1 via the resistors R8 and R9. Further, a capacitor C11 is connected in parallel with the resistors R8 and R9, and a connection point of the capacitor C11 and the resistor R8 is connected to the resistor R1.
1 is connected to the gate of the field effect transistor Q2. Further, a series circuit of a resistor R12 and a zener diode ZD1 is connected in parallel with the capacitor C7.

A preheating start circuit 4 as preheating start means is connected in parallel with the output control circuit 3.
In the preheating start circuit 4, a series circuit of a resistor R15 and a capacitor C15 is connected in parallel with the capacitor C8, and a zener diode ZD2 is connected in parallel with the capacitor C15.
And a series circuit of a capacitor C16. Further, the connection point of the Zener diode ZD2 and the capacitor C16 is connected to the base of the transistor Q4, and a diode is connected between the collector and the emitter of the transistor Q4.
A series circuit of D7 and a resistor R16 is connected, and the collector is connected via a resistor R17 to a connection point of a resistor R4 and a capacitor C8. The base of the transistor Q5 is connected to the connection point of the diode D7 and the resistor R16, and the collector and the emitter of the transistor Q5 are connected to both ends of the Zener diode ZD1.

Further, the preheating start circuit 4 is connected to a reset circuit 7 as reset means. In the reset circuit 7, a series circuit of a resistor R22 and a resistor R23 is connected in parallel to the capacitor C8, a capacitor C22 is connected in parallel to the resistor R23, and a connection point of the resistor R22 and the resistor R23 is: The base of the transistor Q12 is connected, and the collector and the emitter of the transistor Q12 are connected to both ends of the capacitor C15. A series circuit of a phototransistor Q11 and a resistor R24 is connected in parallel with the capacitor C8, and a capacitor C23 is connected in parallel with the resistor R24.
The connection point of Q11 and the resistor R24 is connected to the base of a transistor Q15.
The collector is connected across capacitor C22.

Next, the operation of the discharge lamp lighting device shown in FIG. 1 will be described.

First, when the power is turned on, full-wave rectification is performed by the full-wave rectifier circuit 1, and a pulsating current is applied to the capacitor C1. The inverter circuit 2 controls the DC voltage supplied from the capacitor C1 by switching the transistor Q1 at a high frequency, and the primary winding Tr of the inverter transformer Tr1.
The voltage resonated by the inductance of 1a and the capacitance of the capacitor C2 is induced in the secondary winding Tr1b, and the fluorescent lamp FL
Supplied to Then, the condenser C4 preheats the filaments FLa and FLb of the fluorescent lamp FL, and at the same time, the condenser C4
Is applied to the fluorescent lamp FL to start and turn on the fluorescent lamp FL.

During the period when the capacitor C15 reaches a predetermined voltage value, that is, during the period when the power is turned on and the filaments FLa and FLb of the fluorescent lamp FL are preheated, the Zener diode ZD2 is kept off, so that the transistor Q4 The base current is not supplied to the transistor Q5, and the off state is maintained.The base current is supplied to the transistor Q5, thereby bypassing the Zener diode ZD1 and bypassing the current between the emitter and the collector of the transistor Q3. No gate voltage is applied to the gate of
Since the transistor Q1 is driven only by the capacitance of the capacitor C5, which is not connected in parallel with the capacitor C6, the output of the inverter circuit 2 is in a low state, the oscillation frequency of the transistor Q1 is high, and the output of the inverter circuit 2 is in a low state. At this low output, the filament FLa of the fluorescent lamp FL
, FLb is preheated.

After a predetermined time has passed, the capacitor C1
5 is charged, the Zener diode ZD2 is turned on, so that the base current is supplied to the transistor Q4 and the transistor Q4 is turned on.By bypassing the base current of the transistor Q5, the transistor Q5 is turned off. Since a current corresponding to the capacitors C7 and C8 flows between the collectors according to the voltage value of the commercial AC power supply e, a gate voltage corresponding to the voltage of the commercial AC power supply e is applied to the gate of the field effect transistor Q2, and the field effect Since the resistance value between the drain and source voltages of the transistor Q2 changes and the capacitor C6 whose apparent capacitance is connected to the capacitor C5 is connected, the oscillation frequency of the transistor Q1 decreases and changes. And the fluorescent lamp FL is turned on, and the voltage of the commercial AC power supply e fluctuates. Almost a constant output.

On the other hand, if the fluorescent lamp FL is not mounted while the commercial AC power supply e is turned on, the transformer Tr
Since no voltage is induced in the secondary winding Tr2b of No. 2, the capacitor C21 is not charged, and the Zener diode ZD11 is turned off.Therefore, the light emitting diode LED11 does not emit light, and the phototransistor Q11 is turned off. When the base current of Q15 disappears, transistor Q15 turns off and transistor Q12 turns on, thereby discharging the charge of capacitor C15 and not charging capacitor C15.

Therefore, when the fluorescent lamp FL is mounted in this state, the preheating start circuit 4 operates and the inverter circuit 2
Since the transistor Q1 of the inverter circuit 2 oscillates from the state where the output of the transistor Q1 is lowered, it is possible to prevent the transistor Q1 from being subjected to a large stress.

In a state where the fluorescent lamp FL is mounted, a voltage is induced in the secondary winding Tr2b of the transistor Q2, and after being subjected to full-wave rectification by the full-wave rectification circuit 6, the capacitor C2
1 is charged, the zener diode ZD11 is turned on, the light emitting diode LED1 emits light, and the phototransistor Q11 is turned on, whereby a base current is supplied to the transistor Q15, the transistor Q15 is turned on, and the transistor Q15 is turned on. As a result, the transistor Q12 in which the base current of the transistor Q12 is bypassed turns off, and the capacitor
Put C15 in a chargeable state.

[0036]

According to the discharge lamp lighting device of the present invention, when the discharge lamp is not mounted, the preheating start means is reset, and the output of the inverter means is reduced by the output control means by the preheat start means. Even if the discharge lamp is mounted and the discharge lamp is mounted and started, the output of the inverter means does not become high from the beginning, and it is possible to prevent a large stress from being applied to the inverter means.

[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 circuit diagram showing a conventional discharge lamp lighting device.

[Explanation of symbols]

 2 Inverter circuit as inverter means 3 Output control circuit as output control means 4 Preheating start circuit as preheating start means 5 Mounting detection circuit as mounting detection means 7 Reset circuit as reset means FL Fluorescent lamp as discharge lamp

Claims (1)

[Claims] 1. Variable output inverter means for starting and lighting a discharge lamp, output control means for controlling the output of the inverter means, and preheating for setting the output of the inverter means to be lower than the lighting time for a predetermined time at the time of starting. Starting means; mounting detecting means for detecting a mounting state of the discharge lamp; and reset means for resetting the preheating starting means when the mounting detecting means detects non-mounting of the discharge lamp. Discharge lamp lighting device.