JPH0696887A - Power supply unit, discharge lamp lighting device, and lighting system - Google Patents

Abstract

PURPOSE:To provide a discharge lamp lighting device generating no abnormal oscillation and giving no stress to an inverter circuit. CONSTITUTION:When a power source is turned on, the AC voltage is converted into the high-frequency voltage to turn on a discharge lamp FL. The oscillation frequency of the inverter circuit 22 is set according to a timer resistor R30 and a capacitor C13. When the resistance value of the resistor R31 is increased, the frequency is lowered. When the resistance value is decreased, the frequency is increased. A power detecting diode D12 is operated, a transistor Q13 is operated, and the oscillation frequency is set. When the transistor Q13 is turned on, the frequency is increased. When the transistor Q13 is turned off, the frequency is decreased. When a transistor Q11 is turned off, the transistor Q13 is turned on, and the resistor 31 is shunted by the resistor 30 and a resistor 29. The oscillation frequency of the inverter circuit 22 is increased. The oscillation frequency of the inverter circuit 22 is not decreased to the preset frequency or below to prevent abnormal oscillation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device, a discharge lamp lighting device, and a lighting device which change an output voltage by changing a frequency.

[0002]

2. Description of the Related Art As a conventional discharge lamp lighting device of this type, for example, a structure shown in FIG. 9 is known. This Figure 9
In the discharge lamp lighting device shown in (1), the full-wave rectifier 1 is connected to the commercial AC power source E, and the chopper circuit 2 is connected to the full-wave rectifier 1.

The chopper circuit 2 is an inductor.
It is composed of L1, a switching element Q1 and a diode D1. A smoothing capacitor C1 is connected between the output terminals of the chopper circuit 2.

Further, a modified half-bridge type inverter circuit 3 is connected to the capacitor C1. In the inverter circuit 3, the collectors and emitters of two transistors Q2 and Q3 are connected, and a freewheeling diode D2 and a diode D3 are connected between the collectors and emitters of these transistors Q2 and Q3. A resistor R1, a diode D4, a control winding CT1b of the current transformer CT1 and a capacitor C2 are connected between the base and emitter of the transistor Q2, and a resistor R2 and a diode D are connected between the base and emitter of the transistor Q3.
5, control winding CT1c and capacitor C of current transformer CT1
3 is connected.

The filaments FLa and FLb of the discharge lamp FL are connected between the emitter and collector of the transistor Q3 via the DC cut capacitor C4, the choke coil L2 and the input winding CT1a of the current transformer CT1. . Also, the filaments FLa, FL of these discharge lamps FL
A capacitor C5 for starting is connected between b.

Further, the voltage detection circuit 4 is connected to the output terminal of the full-wave rectifier 1. The output terminal of the voltage detecting circuit 4 is connected to one input terminal of the operational amplifier 5, and the reference voltage source E1 is connected to the other input terminal. The output terminal of the operational amplifier 5 is connected to the voltage dividing resistors R3 and R4 connected in series, and the base of the transistor Q4 is connected to the connection point of the resistors R3 and R4. Further, the collector of the resistor R4 is connected to the base of the transistor Q3, and the emitter of the transistor Q4 is grounded.

A control circuit 6 is connected to the output terminal of the chopper circuit 2. This control circuit 6 has a resistor R5 and a Zener diode ZD1 at the output terminal of the chopper circuit 2.
And the capacitor C6 is connected. A full-wave rectifier 7 is connected to the capacitor C6 via resistors R6, R7, R8, R9, R10, R11 and a transistor Q5. The AC input terminal of the full-wave rectifier 7 has an output winding of the current transformer CT1. Line CT1d is connected.

Further, a reset circuit 8 is connected to the voltage detection circuit 4, the output terminal of the reset circuit 8 is connected to the base of a transistor Q6 via a resistor R12 and a resistor R13, and the collector of the transistor Q6 is It is connected to a resistor R5 and its emitter is grounded.

The AC voltage from the commercial AC power source E is full-wave rectified by the full-wave rectifier 1, boosted by the chopper circuit 2, and then converted into a high frequency by the inverter circuit 3. Also,
When the voltage of the commercial AC power supply E drops, the transistor Q3 of the inverter circuit 3 is stopped according to the voltage detection circuit 4.

Further, in the inverter circuit 3, as shown in FIG. 8, the output voltage also changes when the frequency changes. That is, specifically, the maximum output voltage is obtained at a specific resonance frequency, and the output voltage is reduced in both cases of leading or lagging from this resonance frequency. In addition, in normal use, the phase delay side from the resonance frequency is used.

Before the discharge lamp FL is started, the frequency is increased to lower the output voltage of the inverter circuit 3 to preheat the discharge lamp FL, and after the discharge lamp FL is started, the frequency is decreased to a normal level. The discharge lamp FL is turned on by the output voltage.

[0012]

However, in the case of the conventional example shown in FIG. 9, when the output voltage decreases, the frequency is simply lowered, and when the output voltage rises, on the contrary, the frequency is increased. When the frequency becomes lower than the resonance frequency, the frequency further decreases and enters the phase advance side, and abnormal oscillation may occur as shown in FIG. 10. When abnormal oscillation occurs, oscillation is stopped. .

Further, in order to stop the oscillation in this way,
Since the discharge time of the capacitor C1 is long, if the power is turned on and off at a high speed, if the discharge lamp FL is turned off and then turned on again, the discharge lamp FL is not preheated There is a problem in that the discharge lamp FL may be deteriorated and the transistors Q2 and Q3 of the inverter circuit 3 may be stressed and damaged due to the lighting.

The present invention has been made in view of the above problems, and an object thereof is to provide a power supply device, a discharge lamp lighting device, and a lighting device that do not cause abnormal oscillation and do not stress the inverter circuit. .

[0015]

According to a first aspect of the present invention, there is provided a power supply device which has a DC power supply which is a rectified and smoothed commercial power supply, receives an output voltage of the DC power supply, and changes an oscillation frequency to produce an output. In the controlled inverter circuit, the output voltage of the DC power supply is rectified, and when the output voltage becomes equal to or lower than a set value, the oscillation frequency of the inverter circuit is set to a predetermined high value.

A discharge lamp lighting device according to a second aspect uses the power supply device according to the first aspect, wherein an inverter circuit starts and lights the discharge lamp, sets an oscillation frequency to a high value, and operates the discharge lamp with a minimum output voltage. After preheating and starting the discharge lamp, the oscillation frequency is made lower than the predetermined high oscillation frequency.

A discharge lamp lighting device according to a third aspect of the present invention has a DC power supply that rectifies and smoothes a commercial power supply, receives the output voltage of the DC power supply, and changes the oscillation frequency to keep the output voltage constant. A discharge lamp lighting device provided with an inverter circuit for lighting a discharge lamp, comprising frequency limiting means for preventing an oscillation frequency of the inverter circuit from falling below a predetermined low value.

A discharge lamp lighting device according to a fourth aspect of the present invention is the discharge lamp lighting device according to the second or third aspect, further including a boost chopper circuit on the power supply side of the inverter circuit.

According to a fifth aspect of the present invention, there is provided a lighting apparatus in which the discharge lamp lighting device according to the fourth aspect is built into a main body of a fixture to turn on the discharge lamp.

[0020]

A power supply device according to claim 1 has a direct current power supply that rectifies and smoothes a commercial power supply, receives an output voltage of the direct current power supply, and controls an output voltage by changing an oscillation frequency. The output voltage of the DC power supply is monitored, and when the output voltage becomes equal to or lower than the set value, the oscillation frequency of the inverter circuit is set to a predetermined high value, so abnormal oscillation can be prevented.

A discharge lamp lighting device according to a second aspect uses the power supply device according to the first aspect, and the inverter circuit sets the oscillation frequency to a high value to preheat the discharge lamp at the lowest output voltage, and After the engine is started, the oscillation frequency is set lower than a predetermined high value, so that the frequency does not exceed the frequency set to the high value, so that abnormal oscillation can be prevented.

A discharge lamp lighting device according to a third aspect of the present invention has a DC power source that rectifies and smoothes a commercial power source, receives the output voltage of the DC power source, and changes the oscillation frequency to change the output voltage. In a discharge lamp lighting device equipped with an inverter circuit that keeps the output voltage constant by changing the frequency and lights the discharge lamp, a low frequency is provided because the frequency limiting means that prevents the oscillation frequency of the inverter circuit from falling below a predetermined low value is provided. Since it does not fall below the frequency set in the value, abnormal oscillation can be prevented.

A discharge lamp lighting device according to a fourth aspect of the present invention is the discharge lamp lighting device according to the second or third aspect, in which the booster chopper circuit is provided on the power supply side of the inverter circuit, so that harmonics can be prevented and a low value can be obtained. Since the frequency does not fall below the frequency set in, abnormal oscillation can be prevented.

According to a fifth aspect of the present invention, the discharge lamp lighting device according to the fourth aspect is built in the main body of the fixture to light the discharge lamp, so that harmonics can be prevented and the frequency set to a low value. Since it does not occur below, abnormal oscillation can be prevented.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to a lighting device shown in the drawings.

In FIG. 2, reference numeral 11 denotes a luminaire main body, a reflecting surface is formed on the lower surface of the luminaire main body 11, and lamp sockets 12, 12 are attached to both ends of the reflecting surface. A discharge lamp FL is connected in between. In addition, the circuit shown in FIG. 1 is built in the luminaire main body 11.

As shown in FIG. 1, a commercial AC power source E is connected to a full-wave rectifier 21, a smoothing capacitor C11 is connected to the full-wave rectifier 21, and an inverter circuit 22 is connected to the capacitor C11. The filaments FLa and FLb of the discharge lamp FL are connected to the inverter circuit 22.

Further, a series circuit for voltage division of the resistors R21 and R22 is connected in parallel with the capacitor C11. And, at the connection point of resistors R21 and R22,
Zener diode ZD11 and resistor R23 are connected, and the connection point of these zener diode ZD11 and resistor R23 is
The base of the transistor Q11 is connected, and the emitter of this transistor Q11 is grounded.

On the other hand, similarly, a series circuit of a resistor R25 and a capacitor C12 is connected in parallel with the capacitor C11, and a zener diode ZD12 is connected in parallel with the capacitor C12.
Are connected.

A control circuit 23 is provided between the connection point of the transistor Q11 and the resistor R25 and the Zener diode ZD12.
Are connected. This control circuit 23 includes a transistor Q1
The base of the transistor Q12 is connected to the collector of 1 and the collector of the transistor Q12 via the resistor R24, and the collector of the transistor Q12 is connected to the connection point of the resistor R25 and the capacitor C12. The emitter of this transistor Q12 is a resistor.
It is grounded via R26 and is also grounded via a series circuit of diode D11, resistor R27 and resistor R28. In addition, the base of transistor Q13 is connected to the connection point of resistors R27 and R28.
The emitter of Q13 is grounded via resistor R29. A diode D12 for power feedback is connected to the connection point of the diode D11 and the resistor R27. Further, the connection point of the diode D11 and the resistor R27 is connected to the oscillation circuit 24 via the resistor R30, and the oscillation circuit 24 has the resistor R31 and the capacitor C13.
The oscillation circuit 24 controls the oscillation frequency of the inverter circuit 22. This inverter circuit 22 is also shown in FIG.
As shown in, the output voltage becomes highest at a certain resonance frequency, and the output voltage decreases toward the advanced phase or the delayed phase side of this resonance frequency. Then, the operation is performed on the slow side of the resonance frequency, the output voltage decreases as the frequency increases, and conversely, the output voltage increases as the frequency decreases.

Next, the operation of the embodiment shown in FIG. 1 will be described.

As shown in FIG. 3 (a), when the switch SW is closed and the power is turned on, the full-wave rectifier 21 performs full-wave rectification, and as shown in FIG. 3 (b), the capacitor C11 is used. Smooth and apply voltage to the inverter circuit 22
Convert to high frequency with and turn on the discharge lamp FL. The oscillation frequency of the inverter circuit 22 is set according to the timer resistor R30 and the capacitor C13. It should be noted that this FIG.
In the case of the circuit shown in, the capacitance of the capacitor C13 is fixed and the resistance value of the resistor R30 is changed. The frequency decreases as the resistance value of the resistor R31 increases, and conversely the frequency increases as the resistance value of the resistor R31 decreases.

Further, during normal operation, since there is an output from the full-wave rectifier 21, this voltage is monitored by the output of the full-wave rectifier 21, that is, the Zener diode ZD11 is turned on and the base current is supplied to the transistor Q11. Transistor Q11 turns on, bypassing the base current of transistor Q12, transistor Q12 turns off, and diode D1
1 turns off. Then, the power detection diode D12 operates, and the anode potential of the diode D12 causes the transistor Q13
Operates and sets the oscillation frequency. Then, when the transistor Q13 turns on, the frequency increases, and conversely, when the transistor Q13 turns off, the frequency decreases.

Here, for example, when the switch SW is opened, the discharge of the capacitor C11 is started and the transistor Q11 is started.
Turns off. When the transistor Q11 turns off, the transistor Q12 turns on and a high voltage is generated at the anode of the diode D11. Further, since the transistor Q13 is turned on, the resistor R31 is shunted into the resistor R30 and the resistor R29. Therefore, as shown in FIG. 3E, the oscillation frequency of the inverter circuit 22 becomes high. That is, the oscillation frequency of the inverter circuit 22 is set so as not to fall below a predetermined frequency in order to prevent abnormal oscillation.

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

As shown in FIG. 4, a boost chopper circuit 25 is provided on the commercial AC power source E side of the inverter circuit 22 of the circuit shown in FIG. This boost chopper circuit 25 is
It is composed of an inductor L11, a switching element Q14 and a diode D13.

Two discharge lamps FL1 and FL2 are connected in series to the inverter circuit 22.

Further, the connection point of the resistors R21 and R22 is connected to the non-inverting input terminal of the operational amplifier 26 via the diode D14, the capacitor C14, the resistor R32 and the Zener diode ZD13, and the reference voltage source E1 is connected to the inverting input terminal. Is connected, and the output terminal of the operational amplifier 26 is an inverter circuit.
Connected to 22.

Next, the operation of the embodiment shown in FIG. 4 will be described.

Basically, the operation is similar to that of the circuit shown in FIG.
Reduce harmonics.

Then, as shown in FIG. 5, the output of the non-inverting input terminal of the operational amplifier 26 shown in FIG. 5B changes as the switch SW shown in FIG. The output from the output terminal of the operational amplifier 26 shown in FIG.
Similar to the circuit shown in (1), the oscillation of the inverter circuit 22 is set so as not to fall below a predetermined frequency.

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

As shown in FIG. 6, a full-wave rectifier 31 is connected to the commercial AC power source E, and a boost chopper circuit 32 is connected to the full-wave rectifier 31.

The boost chopper circuit 32 includes an inductor L21, a switching element Q21 and a diode D21.
It consists of A smoothing capacitor C21 is connected between the output terminals of the boost chopper circuit 32.

Further, a modified half-bridge type inverter circuit 33 is connected to the boost chopper circuit 32. This inverter circuit 33 has two transistors Q22.
A collector and an emitter of the transistor Q23 are connected to each other, and a freewheeling diode D22 and a diode D23 are connected between the collector and the emitter of the transistor Q22 and the transistor Q23. A resistor R41, a diode D24, a control winding CT11b of the current transformer CT11 and a capacitor C22 are connected between the base and emitter of the transistor Q22.
A resistor R42, a diode D25, a control winding CT11c of the current transformer CT11 and a capacitor C23 are connected between the emitters.

A capacitor C24 for cutting direct current, a choke coil L22, and an input winding CT11a of the current transformer CT11 are provided between the emitter and collector of the transistor Q23.
The filaments FLa and FLb of the discharge lamp FL are connected via the. Also, the filament of these discharge lamps FL
A capacitor C25 for starting is connected between FLa and FLb.

Further, the voltage detection circuit 34 is connected to the output terminal of the full-wave rectifier 31. The voltage detection circuit 34 includes two resistors R42 and R22 connected in series.
R43, which has a diode D26 and a resistor R43.
44, resistor R45, capacitor C26, diode D27 and resistor R46, and diode D27 and resistor R4
The base of transistor Q24 is connected to the connection point of 6.

At the output terminal of the boost chopper circuit 32,
Resistor R47, Zener diode ZD21 and capacitor C27
Are connected to the emitter of the transistor Q24 via the diode D28 at the connection point of the resistor R47 and the capacitor C27. And Zener diode
A full-wave rectifier 35 is connected to ZD21 via resistors R48, R49, R50, R51, R52, R53 and a transistor Q25.
The current transformer CT is connected to the AC input terminal of this full-wave rectifier 35.
11 output windings CT11d are connected.

Next, the operation of the above embodiment will be described with reference to FIG.

First, when the switch SW is turned off, as shown in FIG.
As shown in (a), the base current of the transistor Q24 disappears, the transistor Q24 turns off, and the capacitors C26 and C27 are discharged.

Then, as the voltage of the capacitor C27 decreases, the transistor Q24 turns off. When the transistor Q24 is off, the inverter circuit 33 oscillates at the preset maximum frequency and the output voltage drops. Further, since the inverter circuit 33 continues to oscillate even after the switch SW is opened, the capacitor C21 is also rapidly discharged, and the oscillation of the inverter circuit 33 is stopped. In this case, since the frequency is high, it is set to a state higher than the resonance frequency and enters the slow phase region, so that it does not enter the phase advance region side and abnormal oscillation does not occur.

When the switch SW is closed again and the power is turned on, as shown in FIG.
Since the Q24 remains off, the output voltage is at the highest frequency as shown in Fig. 7 (e), so the discharge lamp FL is preheated before the discharge lamp FL is started. FL deterioration can be suppressed.

Furthermore, since the discharge time of the capacitor C21 can be shortened, the instantaneous light can be prevented.

[0054]

According to the power supply device of the first aspect, the commercial power supply has a rectified and smoothed DC power supply, and the output voltage is controlled by receiving the output voltage of the DC power supply and changing the oscillation frequency. Monitor the output voltage of the DC power supply of the inverter circuit, and when this output voltage falls below the set value, the oscillation frequency of the inverter circuit is set to a predetermined high value.
Abnormal oscillation can be prevented.

According to the discharge lamp lighting device of the second aspect,
With the power supply device according to claim 1, the inverter circuit sets the oscillation frequency to a high value to preheat the discharge lamp with the lowest output voltage, and after starting the discharge lamp, lowers the oscillation frequency from a predetermined high value. Since the frequency does not exceed the frequency set to a high value, abnormal oscillation can be prevented.

According to the discharge lamp lighting device of the third aspect,
It has a DC power supply that rectifies and smoothes a commercial power supply, receives the output voltage of this DC power supply, changes the output voltage by changing the oscillation frequency, and keeps the output voltage constant by changing the frequency. In a discharge lamp lighting device equipped with an inverter circuit for lighting, since the frequency limiting means for preventing the oscillation frequency of the inverter circuit from falling below a predetermined low value is provided, it does not fall below the frequency set to a low value. Abnormal oscillation can be prevented.

According to the discharge lamp lighting device of the fourth aspect,
In addition to the discharge lamp lighting device according to claim 2 or 3, since the booster chopper circuit is provided on the power supply side of the inverter circuit, harmonics can be prevented and the frequency does not fall below a frequency set to a low value. Abnormal oscillation can be prevented.

According to the lighting device of the fifth aspect, since the discharge lamp lighting device of the fourth aspect is built in the fixture main body and the discharge lamp is turned on, harmonics can be prevented and
Since it will not be lower than the frequency set to a low value,
Abnormal oscillation can be prevented.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of a lighting device of the present invention.

FIG. 2 is a perspective view showing the outer appearance of the same.

FIG. 3 is a timing chart showing the same operation as above. (A) Switch SW operating state (b) Capacitor C11 voltage (c) Capacitor C12 voltage (d) Transistor Q11 operating state (e) Inverter circuit 22 operating state

FIG. 4 is a circuit diagram showing another embodiment of the above.

FIG. 5 is a timing chart showing the same operation as above. (A) Operating state of switch SW (b) Voltage VA (c) Voltage VB

FIG. 6 is a circuit diagram showing an illumination device of another embodiment of the above.

FIG. 7 is a timing chart showing the same operation as above. (A) Voltage of capacitor C21 (b) Voltage of resistor R44 (c) Operating state of transistor Q24 (d) Voltage of Zener diode ZD21 (e) Oscillation state of inverter circuit 33

FIG. 8 is a graph showing a relationship between voltage and frequency of an inverter circuit.

FIG. 9 is a circuit diagram showing a conventional discharge lamp lighting device.

FIG. 10 is a timing chart showing the same operation. (A) Capacitor C1 voltage (b) Transistor Q3 collector and emitter current

[Explanation of symbols]

 11 Lighting equipment body 22, 33 Inverter circuit 25, 32 Boost chopper circuit FL, FL1, FL2 Discharge lamp

Claims (5)

[Claims] 1. An inverter circuit having a direct current power source that rectifies and smoothes a commercial power source, receives an output voltage of the direct current power source, and controls an output by changing an oscillation frequency. A power supply device characterized by monitoring and setting an oscillation frequency of the inverter circuit to a predetermined high value when the output voltage becomes equal to or lower than a set value. 2. An inverter circuit starts a discharge lamp to illuminate it, pre-heats the discharge lamp with a minimum output voltage by setting an oscillation frequency to a high value, and after starting the discharge lamp, a voltage higher than the predetermined high value of the oscillation frequency. A discharge lamp lighting device using the power supply device according to claim 1, wherein the lighting device is low. 3. An inverter circuit which has a DC power supply that rectifies and smoothes a commercial power supply, receives the output voltage of the DC power supply, and changes the oscillation frequency to keep the output voltage constant and light the discharge lamp. The discharge lamp lighting device according to claim 1, further comprising frequency limiting means for preventing the oscillation frequency of the inverter circuit from falling below a predetermined low value. 4. The discharge lamp lighting device according to claim 2, wherein a boost chopper circuit is provided on the power supply side of the inverter circuit. 5. A lighting device comprising the discharge lamp lighting device according to claim 4 built in a main body of a fixture and lighting the discharge lamp.