JPH07320888A - Lighting device for electric discharge lamp - Google Patents

Abstract

PURPOSE:To provide an electric discharge lamp lighting device capable of properly detecting the service life end of an electric discharge lamp, whether the lamp lights at full capacity or under control. CONSTITUTION:A dimmer switch SW1 is opened at the time of full capacity lighting, and when a fluorescent lamp FL nears a service life end, the voltage thereof rises. As a result, the voltage of a capacitor C2 rises and a rise in the voltage of a capacitor 3 follows. Also, the non-reversal input of an operation amplifier 3 becomes large, and the output of an inverter circuit 2 is lowered with a control section 4. Current flowing to a resistor R4 is bypassed between the collector and emitter of a transistor Q2, and voltage supplied to the reversal input terminal of the amplifier 3 drops, thereby reducing voltage as a comparison object. Thus, a service life end can be detected at relatively low voltage. When the switch SW1 is closed, voltage applied to the reversal input terminal is higher than at the time of full capacity lighting and, therefore, the service life end of the fluorescent lamp FL can be properly detected at the same level, whether the lamp FL lights at full capacity or under control.

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 capable of lighting all lights and dimming lights.

[0002]

2. Description of the Related Art As a conventional discharge lamp lighting device capable of this kind of all-light and dimming lighting, for example, a structure shown in FIG. 5 is known.

The conventional example shown in FIG. 5 is a commercial AC power source E.
Is connected to the input terminal of the full-wave rectifier 1 such as a diode bridge, and the inverter circuit 2 is connected to the output terminal of the full-wave rectifier 1.

A fluorescent lamp FL as a discharge lamp is connected to the inverter circuit 2.

Further, a series circuit of a voltage dividing capacitor C1 and a capacitor C2 is connected between the output terminals of the inverter circuit 2, and a diode is provided in parallel with the capacitor C2.
D1 is connected, a series circuit of a diode D2 and a capacitor C3 is connected in parallel to the diode D1, and the connection point of the diode D2 and the capacitor C3 is grounded via a resistor R1.

Further, the connection point of the diode D2 and the resistor R1 is connected to the non-inverting input terminal of the operational amplifier 3 for comparison, and the inverting input terminal of this operational amplifier 3 is connected to the reference voltage source Vre.
connected to f.

The output terminal of the operational amplifier 3 is
The output of the inverter circuit 2 is connected to a control unit 4 that connects the total light output and the dimming output stepwise.

Further, the control unit 4 is a dimming switch SW1.
Is connected to the collector of a transistor Q1 connected to the base, and the emitter is grounded via a resistor R2.

When all the lights are on, a switch SW for dimming
1, 1 is opened, the voltage of the commercial AC power source E is full-wave rectified by the full-wave rectifier 1, converted into high-frequency AC by the inverter circuit 2, and all lights are output, and the fluorescent lamp FL is turned on all lights.

On the other hand, when the dimming is lit, the dimming switch SW1
Is closed, the output of the inverter circuit 2 is reduced to the dimming output by the control unit 4, and the fluorescent lamp FL is dimmed and turned on.

When the fluorescent lamp FL approaches the end of its life, the voltage of the fluorescent lamp FL rises.
Rises, the non-inverting input of the operational amplifier 3 increases, and the control unit 4 reduces the output of the inverter circuit 2. That is, when the fluorescent lamp FL approaches the end of its life, the fluorescent lamp FL may cause half-wave discharge or the like, and the inverter circuit 2 may abnormally oscillate. Therefore, the output of the inverter circuit 2 is lowered.

Further, as another conventional discharge lamp lighting device capable of performing all-light and dimming lighting, for example, a configuration shown in FIG. 6 is known.

The conventional example shown in FIG. 6 is a field effect transistor Q11 which serves as a switching element for the DC power source E1.
And a half-bridge type inverter circuit 11 consisting of a series circuit of field effect transistor Q12 is connected.The feedback winding CT1b of the current transformer CT1 is connected between the gate and source of the transistor Q11 of this inverter circuit 11 and this feedback circuit is connected. The winding CT1b is connected to the gate of the field effect transistor Q11 via the waveform improving circuit 12, and the feedback winding CT1c of the current transformer CT1 is connected between the gate and the source of the transistor Q12.
This feedback winding CT1c is connected to the gate of the field effect transistor Q12 via the waveform improving circuit 13.

Further, between the drain and the source of the field effect transistor Q12, the detection winding CT1a of the current transformer CT1,
The fluorescent lamp FL is connected via a DC cut capacitor C11 and a ballast choke coil L11.

Further, a preheating capacitor C12 is connected to the non-power source side of the fluorescent lamp FL.

A series circuit of a voltage dividing capacitor C13 and a capacitor C14 is connected to the fluorescent lamp FL,
Capacitor C14 has diode D11 and diode D1
2 is connected. Further, the connection point of the capacitors C13 and C14 is connected to the negative electrode of the DC power source E1 via the diode D13, the resistor R11 and the capacitor C15.

A resistor R12 is connected in parallel with the capacitor C15, and the connection point of the resistor R11 and the capacitor C15 is connected through a Zener diode ZD11 to a transistor Q1.
The series circuit of the resistor R13 and the DC power supply E2, the series circuit of the resistor R14 and the dimming switch SW11, and the resistor R15 are connected in parallel between the collector and the emitter of the transistor Q13. ing.

Further, the connection point of the resistors R13 and R14 is connected to the base of the transistor Q14, the collector of the transistor Q14 is connected to the base of the transistor Q15, and the transistor Q14 and the transistor Q15 are connected.
The emitter of is connected to the negative electrode of the DC power supply E1 via the resistor R16. A resistor R17 is connected between the emitter and collector of the transistor Q15, and a resistor R18
It is connected to the. Then, the output adjusting circuit 14 is configured.

Further, a capacitor C16, a diode D14 and a diode D15 are connected in parallel with a series circuit of the resistor R16, the emitter and collector of the transistor Q15 and the resistor R18.
And a voltage doubler circuit 15 consisting of a capacitor C17 are connected.The capacitor C17 is connected to the feedback winding CT1c of the current transformer CT1.
It is connected to the.

When all lights are turned on, switch SW11 for dimming
Is opened, the base current of the transistor Q14 is increased, the effective resistance value between the collector and the emitter of the transistor Q14 is decreased, and the current flowing in the transistor Q15 is increased. Converts the DC voltage to high-frequency AC, lengthens the saturation time of the feedback winding CT1c, and turns on / off the field effect transistor Q11 and field effect transistor Q12 alternately for a long time to lower the frequency of the inverter circuit 11. , Inverter circuit
The output of 11 is set to all light output, and the fluorescent lamp FL is lit at high frequency in all light state.

On the other hand, when the dimming is turned on, the dimming switch SW11 is closed to reduce the base current of the transistor Q14 to increase the substantial resistance value between the collector and the emitter of the transistor Q14, and the transistor Q15. , The inverter circuit 11 converts the DC voltage of the DC power supply E1 into high-frequency AC, shortens the saturation time of the feedback winding CT1c, and alternately turns on the field-effect transistor Q11 and the field-effect transistor Q12. The off time is shortened, the frequency of the inverter circuit 11 is increased, and the inverter circuit 11
Is used as the dimming output, and the fluorescent lamp FL is lit at a high frequency in the dimming state.

When the fluorescent lamp FL reaches the end of its life and the voltage of the fluorescent lamp FL rises, the voltage of the capacitor C14 rises, the voltage of the capacitor C15 rises, and the Zener diode ZD11 turns on, thereby turning on the transistor Q13. Turns on, bypasses the base current of the transistor Q14, increases the effective resistance value between the collector and emitter of the transistor Q14, increases the effective resistance value between the collector and emitter of the transistor Q15, and The saturation time of the line CT1c is shortened, the frequency of the inverter circuit 11 is increased, the output of the inverter circuit 11 is made extremely small, and the field effect transistors Q11 and Q12 of the inverter circuit 11 are protected.

[0023]

However, the lamp voltage of the fluorescent lamp FL at the time of dimming lighting is higher than the lamp voltage of the fluorescent lamp FL at the time of full light lighting in both the discharge lamp lighting devices of FIGS. 5 and 6. Therefore, if the lamp voltage during all-light lighting and during dimming lighting is kept constant, the end of life cannot be detected sufficiently during all-light lighting, or the end of life is not reached during dimming lighting, but the end of life is reached. There is a risk of being destroyed.

That is, in the circuit shown in FIG. 3, when a resistor RFL and a diode DFL are connected to the fluorescent lamp to artificially change the life of the fluorescent lamp FL, the end of the life of the fluorescent lamp FL is considered to be a half-wave resistance RFL. Assuming that the fluorescent lamp FL has a pseudo end of life by increasing the resistance value of, as shown in FIG. 4, even if the detection voltage reaches the end of life when all lights are turned on, the detection voltage is the same during dimming lights. The voltage is not the end of life.

Therefore, there is a problem that the end of the life cannot be the same in all light lighting and dimming lighting only by detecting the voltage of the fluorescent lamp FL.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a discharge lamp lighting device that can be reliably detected during all-light lighting and dimming lighting.

[0027]

A discharge lamp lighting device according to claim 1, wherein an output of the discharge lamp is varied stepwise, and an inverter circuit capable of lighting the discharge lamp in a full light and dimming state, and a lamp of the discharge lamp. Detection means for detecting at least one of voltage and lamp current, reference voltage means for setting a reference voltage, any one of the lamp voltage and the lamp current detected by the detection means, and the reference of the reference voltage means Comparing means for comparing the voltages, control means for controlling the output of the inverter circuit when the comparing means determines that one of the lamp voltage and the lamp current detected by the detecting means is high, and the reference voltage means And a correction unit that corrects the reference voltage in accordance with the total light and dimming state of the discharge lamp.

According to another aspect of the present invention, there is provided a discharge lamp lighting device, wherein an output of the discharge lamp is changed stepwise, and an inverter circuit capable of lighting the discharge lamp in a full light and dimming state and at least a lamp voltage and a lamp current of the discharge lamp. Detecting means for detecting either one, and a control means for controlling the output of the inverter circuit when it is determined that at least one of the lamp current and the lamp current detected by the detecting means is higher than a set value, And a correction unit that corrects the set value corresponding to each of the total light and the dimming state of the discharge lamp.

[0029]

In the discharge lamp lighting device according to the present invention, at least one of the lamp voltage and the lamp current of the discharge lamp is detected by the detecting means, and the lamp voltage or the lamp current detected by the detecting means is compared by the comparing means. When the control means determines that the voltage detected by the detecting means is higher than the reference voltage of the voltage means, the output of the inverter circuit is controlled by the correcting means, and the reference voltage of the reference voltage means is adjusted by the correcting means to the total light of the discharge lamp. In order to compensate for each dimming condition,
Even if the lamp voltage of the discharge lamp is higher than the lamp voltage in the dimming state, it can be corrected to the same level, so that the end of life of the discharge lamp can be detected in either the dimming state or the dimming state.

In the discharge lamp lighting device according to the present invention, the detecting means detects at least one of the lamp voltage and the lamp current of the discharge lamp, and the detecting means detects at least one of the lamp current and the lamp current. Is determined to be higher than the set value, the control means controls the output of the inverter circuit, and the correction means corrects the set value according to the total light and dimming state of the discharge lamp. Even if the lamp voltage of the discharge lamp is higher than the lamp voltage in the full-light state, it can be corrected to the same level, so that the end of life of the discharge lamp can be detected in either the full-light state or the dimming state.

[0031]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the discharge lamp lighting device of the present invention will be described below with reference to the drawings. The portions corresponding to the conventional example shown in FIG. 5 and FIG. 6 will be described with the same reference numerals.

In the embodiment shown in FIG. 1, an input terminal of a full-wave rectifier 1 such as a diode bridge is connected to a commercial AC power source E, and an inverter circuit 2 is connected to an output terminal of the full-wave rectifier 1.

A fluorescent lamp FL as a discharge lamp is connected to the inverter circuit 2.

A series circuit of a voltage dividing capacitor C1 and a capacitor C2 as a detecting means is connected between the output terminals of the inverter circuit 2, and a diode D1 is connected in parallel to the capacitor C2. A series circuit of a diode D2 and a capacitor C3 is connected in parallel with, and the connection point of the diode D2 and the capacitor C3 is grounded via a resistor R1.

Further, the connection point of the diode D2 and the resistor R1 is connected to the non-inverting input terminal of the comparing operational amplifier 3 as the comparing means, and the inverting input terminal of the operational amplifier 3 serves as the reference voltage means via the resistor R2. Reference voltage source Vre
It is connected to f and is grounded through resistors R3 and R4.

Further, the output terminal of the operational amplifier 3 is connected to the control section 4 as a control means for connecting the output of the inverter circuit 2 stepwise between the total light output and the dimming output.

On the other hand, the control section 4 is a dimming switch SW1.
Is connected to the collector of transistor Q1 which is connected to the base.

The base of the transistor Q1 is connected to the base of a transistor Q2 as a correcting means, the collector and the emitter of the transistor Q2 are connected to one end and the other end of a resistor R4, and the base of the transistor Q2 is a resistor R5. Is connected to the inverting input terminal of the operational amplifier 3 via.

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

First, the switch SW1 for dimming when all lights are on
Is opened, and the base current is supplied to the transistor Q1 so that the output of the inverter circuit 2 is in a full optical output state, the voltage of the commercial AC power source E is full-wave rectified by the full-wave rectifier 1, and the inverter circuit 2 outputs high-frequency waves. All the light is converted into alternating current and the fluorescent lamp FL is turned on.

When the fluorescent lamp FL approaches the end of its life, the voltage of the fluorescent lamp FL rises.
Rises, the voltage of the capacitor C3 rises, the non-inverting input of the operational amplifier 3 increases, and the control unit 4 lowers the output of the inverter circuit 2. On the other hand, since the dimming switch SW1 is opened, the transistor Q2
Since the base current is supplied to the resistor R4, the current flowing through the resistor R4 is bypassed between the collector and the emitter of the transistor Q2, and the voltage input to the inverting input terminal of the operational amplifier 3 decreases, which lowers the voltage to be compared. Detects the end of life with a relatively low voltage.

When the dimming switch SW1 is closed, the base current of the transistor Q1 is bypassed, the inverter circuit 2 lowers the output to the dimming output state, and the base current of the transistor Q2 is turned off. Then, since the transistor Q2 is turned off, the voltage input to the inverting input terminal of the operational amplifier 3 increases and the voltage to be compared decreases, so that the end of life is detected at a higher voltage than in the case of full light.

As described above, the voltage applied to the inverting input terminal at the time of dimming lighting is higher than at the time of dimming lighting, so that the same level is obtained at all lighting and dimming lighting. Since the end of life of the fluorescent lamp FL can be detected with certainty, it is possible to prevent the end of life from being detected when all lights are on, or to prevent erroneous detection of end of life when dimming and lighting, even though it is not the end of life. .

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

In the embodiment shown in FIG. 2, the field effect transistor Q11 serving as a switching element for the DC power source E1 is used.
And a half-bridge type inverter circuit 11 consisting of a series circuit of field effect transistor Q12 is connected.The feedback winding CT1b of the current transformer CT1 is connected between the gate and source of the transistor Q11 of this inverter circuit 11 and this feedback circuit is connected. The winding CT1b is connected to the gate of the field effect transistor Q11 via the waveform improving circuit 12, and the feedback winding CT1c of the current transformer CT1 is connected between the gate and the source of the transistor Q12.
This feedback winding CT1c is connected to the gate of the field effect transistor Q12 via the waveform improving circuit 13.

Further, the detection winding CT1a of the current transformer CT1 is connected between the drain and the source of the field effect transistor Q12,
The fluorescent lamp FL is connected via a DC cut capacitor C11 and a ballast choke coil L11.

Further, a preheating capacitor C12 is connected to the non-power source side of the fluorescent lamp FL.

A series circuit of a voltage dividing capacitor C13 and a capacitor C14 is connected to the fluorescent lamp FL,
The diode D11 is connected to the capacitor C14.
Further, the connection point of the capacitors C13 and C14 is connected to the negative electrode of the DC power source E1 via the diode D13, the resistor R11 and the capacitor C15.

A resistor R12 is connected in parallel to the capacitor C15, and the connection point of the resistor R11 and the capacitor C15 is connected to the base of the transistor Q13 via a Zener diode ZD11 as a detecting means. Between the collector and the emitter of, the series circuit of resistor R13 and DC power supply E2, resistor R14, diode D16
Further, a series circuit of the dimming switch SW11 and the resistor R15 are connected in parallel.

Further, the connection point of the resistors R13 and R14 is connected to the base of the transistor Q14, the collector of this transistor Q14 is connected to the base of the transistor Q15, and the transistor Q14 and the transistor Q15 are connected.
The emitter of is connected to the negative electrode of the DC power supply E1 via the resistor R16. A resistor R17 is connected between the emitter and collector of the transistor Q15, and a resistor R18
It is connected to the. Then, the output adjusting circuit 14 as a control means is configured.

Further, in parallel with the series circuit of the resistor R16, the emitter and collector of the transistor Q15 and the resistor R18, a capacitor C16, a diode D14 and a diode D15 are connected.
And a voltage doubler circuit 15 consisting of a capacitor C17 are connected.The capacitor C17 is connected to the feedback winding CT1c of the current transformer CT1.
It is connected to the.

Further, from the connection point of the diode D16 and the dimming switch SW11, a resistor R19 is connected to a capacitor.
It is connected to the correction means 16 in parallel with C14. This correction means 16 connects a series circuit of capacitor C18 and diode D17 in parallel to capacitor C14, connects the emitter and collector of transistor Q16 between both terminals of diode D17, and connects the base to resistor R19. It was done.

Next, the operation of the embodiment shown in FIG. 2 will be described.

First, when all lights are turned on, the dimming switch SW11 is opened, the base current of the transistor Q14 is increased, and the substantial resistance value between the collector and the emitter of the transistor Q14 is lowered to make the transistor Q15. The inverter circuit 11 converts the DC voltage of the DC power supply E1 into high-frequency AC by increasing the flowing current, and lengthens the saturation time of the feedback winding CT1c to alternately turn on and off the field effect transistor Q11 and the field effect transistor Q12. The inverter circuit 11 and the frequency of the inverter circuit 11 is lowered.
The output of is the full light output, and the fluorescent lamp FL is lit at high frequency in the full light state.

When the fluorescent lamp FL reaches the end of its life and the voltage of the fluorescent lamp FL rises, the voltage of the capacitor C14 rises, the voltage of the capacitor C15 rises, and the Zener diode ZD11 turns on, thereby turning on the transistor Q13. Turns on, bypasses the base current of the transistor Q14, increases the effective resistance value between the collector and emitter of the transistor Q14, increases the effective resistance value between the collector and emitter of the transistor Q15, and The saturation time of the line CT1c is shortened, the frequency of the inverter circuit 11 is increased, the output of the inverter circuit 11 is made extremely small, and the field effect transistors Q11 and Q12 of the inverter circuit 11 are protected. When all lights are on, the transistor Q16 is off because the base current is not supplied because the dimming switch SW11 is open.Therefore, the capacitor C18 is not connected in parallel to the capacitor C14. The capacity is decreasing and the threshold is set to a relatively low voltage.

On the other hand, when the dimming operation is turned on, the dimming switch SW11 is closed to reduce the base current of the transistor Q14 to increase the substantial resistance value between the collector and the emitter of the transistor Q14, and the transistor Q15. , The inverter circuit 11 converts the DC voltage of the DC power supply E1 into high-frequency AC, shortens the saturation time of the feedback winding CT1c, and alternately turns on the field-effect transistor Q11 and the field-effect transistor Q12. The off time is shortened, the frequency of the inverter circuit 11 is increased, and the inverter circuit 11
Is used as the dimming output, and the fluorescent lamp FL is lit at a high frequency in the dimming state. Also, since the dimming switch SW11 is closed, the base current is supplied to the transistor Q16, the transistor Q16 is turned on, and the capacitor C18 is connected in parallel with the capacitor C14 to increase the combined capacitance. Even when the FL voltage is higher than the all-light lighting state, the voltage increase at the end of life can be reliably detected according to the level of the all-light lighting state.

As described above, the voltage applied to the inverting input terminal at the time of dimming lighting is higher than that at the time of dimming lighting, so that the same level is obtained at all lighting and dimming lighting. Since the end of life of the fluorescent lamp FL can be detected with certainty, it is possible to prevent the end of life from being detected when all lights are on, or to prevent erroneous detection of end of life when dimming and lighting, even though it is not the end of life. . Further, since the detection level of the voltage at the end of life is not increased, it is possible to prevent the temperature of the inverter circuit 11 from rising at the end of life.

[0058]

According to the discharge lamp lighting device of the first aspect of the present invention, the correction means corrects the reference voltage of the reference voltage means in correspondence with the total light and the dimming state of the discharge lamp. Thus, even if the lamp voltage of the discharge lamp is higher than the lamp voltage in the full-light state, it can be corrected to the same level, so that the end of life of the discharge lamp can be detected in either the full-light state or the dimming state.

According to the discharge lamp lighting device of the second aspect,
Since the correction value is corrected by the correction means according to the total light and dimming state of the discharge lamp, even if the lamp voltage of the discharge lamp is higher than the lamp voltage of the full light state in the dimming state, the same level is set. Since correction is possible, the end of life of the discharge lamp can be detected in either the full-light state or the dimming state.

[Brief description of drawings]

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

FIG. 2 is a circuit diagram showing a discharge lamp lighting device of another embodiment of the same.

FIG. 3 is a circuit diagram showing a circuit configuration in which a fluorescent lamp is put into a state of end of life in a pseudo manner.

FIG. 4 is a graph showing the relationship between the end of life and the detected voltage.

FIG. 5 is a circuit diagram showing a conventional discharge lamp lighting device.

FIG. 6 is a circuit diagram showing another conventional discharge lamp lighting device.

[Explanation of symbols]

 2 Inverter circuit 3 Operational amplifier as comparison means 4 Control section as control means 11 Inverter circuit 14 Output adjustment circuit as control means 16 Correction means C2 Capacitor FL as detection means FL Lamp as discharge lamp Q2 Transistor as correction means Vref Reference voltage source as reference voltage means ZD11 Zener diode as detection means

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Satoshi Takeda 6-78 Minamimachi, Mishima City, Shizuoka Prefecture Tokyo Electric Co., Ltd. Mishima Plant

Claims (2)

[Claims] 1. An inverter circuit capable of gradually changing an output to light a discharge lamp in a full light and dimming state, and a detection means for detecting at least one of a lamp voltage and a lamp current of the discharge lamp. A reference voltage means for setting a reference voltage, a comparing means for comparing one of the lamp voltage and the lamp current detected by the detecting means and a reference voltage of the reference voltage means, and the detecting means by the comparing means. When the lamp voltage or the lamp current detected in is determined to be high, the control means for controlling the output of the inverter circuit, the reference voltage of the reference voltage means of the full-light and dimming state of the discharge lamp A discharge lamp lighting device, comprising: a correction unit that corrects each of them. 2. An inverter circuit capable of gradually changing the output and lighting a discharge lamp in a full light and dimming state, and a detection means for detecting at least one of a lamp voltage and a lamp current of the discharge lamp. A control unit that controls the output of the inverter circuit when it is determined that at least one of the lamp current detected by the detection unit and the lamp current is higher than a set value; A discharge lamp lighting device, comprising: a correction unit that corrects light and a dimming state.