JP2950663B2 - Discharge lamp lighting device - Google Patents

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 apparatus for controlling lighting of a discharge lamp such as a metal halide lamp.

[0002]

2. Description of the Related Art When a high-pressure discharge lamp such as a metal halide lamp is started from a cold state, the light output does not easily increase with the same electric power unless the vapor pressure of the luminescent metal becomes high after a long time. Therefore, in order to quickly start the light output of such a lamp, a method of inputting a large amount of lamp power immediately after starting and reducing the lamp power to a predetermined lamp power with the passage of time to perform the rated lighting has already been disclosed in Japanese Patent Application Laid-Open No. H11-163873. It is known from JP-A-2-10697.

[0003]

However, in the apparatus for implementing the above method, since the lamp state is not detected, there is a possibility that the light output may be excessive or insufficient depending on the lamp state. In the case of a lamp in a cold state, it is good, but if it is turned on for a long time and then turned off and restarted in a short time, if it is turned off after a long time and then restarted after a short time, after being turned on for a short time If the lamp is warm, such as when it is turned off and restarted in a short time, the specified light output will not be obtained immediately after restarting. There is a problem that the service life is shortened.

An object of the present invention is to provide a discharge lamp lighting device that quickly starts light output irrespective of a lamp voltage, a light-off state, and a lighting state, and that does not generate too much light output. It is the purpose.

[0005]

In order to solve the above problems, a discharge lamp lighting device of the present invention detects a lamp current supply means, a discharge lamp connected to the lamp current supply means, and a lamp voltage. A lamp voltage detecting means, a lamp current detecting means for detecting a lamp current, a power control means for controlling the lamp power in response to outputs of the lamp voltage detecting means and the lamp current detecting means, and a lighting control means;
Lighting control means for detecting the lamp voltage in the lamp starting region.
If the output voltage of the output means is input and it is less than the predetermined lamp voltage,
The output signal decreases as the lamp voltage increases,
Lamp power calculation means for setting the output signal to 0 when the voltage is higher than
And a bias means, wherein the lighting control means
Ramp by the sum output of the power calculation means and bias means
By controlling the output of the current supply means, when the lamp voltage is low, the lamp current supply means is controlled to input a large lamp power to the discharge lamp, and when the lamp voltage is high, the lamp current supply means is controlled. entering a small lamp power to the discharge lamp, after lamp ignition region is characterized by being configured the discharge lamp to control so as to rated lighting.

Further, the lighting control means includes a lamp power control unit.
Operating at a predetermined lamp voltage by being connected to
It has constant switching means so that the lamp voltage becomes higher than a predetermined voltage.
As a result, the decrease in lamp power
It is configured to switch the time constant to increase the time constant.
It is characterized by having been done.

Another discharge lamp lighting device is a lamp.
Current supply means connected to the lamp current supply means
Discharge lamp and lamp voltage detecting means for detecting lamp voltage
A lamp current detecting means for detecting a lamp current;
Receiving the outputs of the pump voltage detecting means and the lamp current detecting means
Power control means for controlling lamp power, lighting control means,
The lighting control means is provided in the lamp starting area.
The output voltage of the pump voltage detection means is input,
Immediately after, at least compared to the lamp power during stable lighting
Set the initial lamp power so that the specified lamp power flows.
Starting initial power setting means
Large when lamp voltage is low according to power and lamp voltage
When the starting power and lamp voltage are high, a small starting power
Input the larger lamp power to the discharge lamp and start the lamp.
After the operating range, control the discharge lamp so that it is rated
It is characterized by having such a configuration.

The starting initial power setting means may include a
Turn-off time detection means for detecting the turn-off time
At least immediately after starting and restarting according to the output of the
It is much longer than the lamp power at the time of constant lighting.
The initial lamp power can be set so that a large lamp power flows.
Starting control signal setting trigger means, and lighting control means
Is the starting power according to the lighting time and the starting power according to the lamp voltage.
Discharge the lamp power of the larger of the dynamic power
The discharge lamp after the lamp starting area.
It is characterized in that it is controlled to light.

[0009]

[0010]

[0011]

According to the above construction, in the starting region of the discharge lamp, when the lamp voltage detecting means detects a low lamp voltage, the output of the lamp current supply means is controlled to supply a large lamp power, and when the high lamp voltage is detected. Controls the output of the lamp current supply means to supply a small amount of lamp power, so that the lamp power can be reliably controlled and the lamp can be lit at the rated lamp power during stable lighting.

[0012]

[0013]

A lamp power calculating means for decreasing the output signal with an increase in the lamp voltage when the lamp voltage is lower than a predetermined lamp voltage and making the output signal zero when the lamp voltage is higher than the predetermined lamp voltage; and a bias means. And the output of the lamp current supply means is controlled by the sum output of the bias means and the lamp. Therefore, in the lamp starting region, when the lamp voltage is lower than a predetermined lamp voltage, a large lamp power at the time of starting is inputted to quickly increase the luminous flux of the discharge lamp. When the lamp voltage is equal to or higher than a predetermined lamp voltage, the lamp is lit at the rated power.

Further, when the lamp voltage becomes equal to or higher than a predetermined voltage, the time constant is switched by the time constant switching means so as to increase the lamp power reduction time constant in the lamp power calculating means. Since the rated lighting is gradually changed, the light output can be shifted to the stable lighting without a large change after the light output is set to the rated output after the start.

Further, the initial lamp power is set so that at least a predetermined lamp power larger than the lamp power at the time of stable lighting is supplied immediately after the starting and restarting. Even in the case where the lamp is near, by inputting a large lamp power, even if the encapsulating metal adheres to the tube wall of the lamp when the lamp is turned off, a light output close to the time of stable lighting can be obtained immediately after the restart.

Further, the initial lamp power is set so that at least a predetermined lamp power larger than the lamp power at the time of stable lighting is supplied immediately after the start / restart according to the output of the light-off time detecting means. By setting the initial lamp power to be larger when the lamp is longer than when the lamp is turned off, the luminous efficiency does not decrease because the vapor pressure of the encapsulated metal does not decrease when the turn-off time is short. In such a case, a large amount of lamp power is not input at restart in such a case.On the contrary, as the light-off time becomes longer, the vapor pressure decreases and the enclosed metal adheres to the tube wall. In this case, a large lamp power can be input at the time of restart, so that a light output close to the time of stable lighting can be obtained immediately after restart.

[0018]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a basic configuration of a discharge lamp lighting device according to one embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a DC power supply, and an inverter circuit 2 is driven by the DC power supply 1, inverts the DC voltage at a predetermined frequency, and outputs a rectangular wave voltage. These DC power supply 1 and inverter 2 constitute lamp current supply means 3. The inverter circuit 2 has a starting circuit 4 including an inductance component as a load circuit, and a discharge lamp 5 such as a metal halide lamp. Furthermore, the output of the DC power supply 1
A DC voltage detection circuit 6 for detecting a DC voltage and a DC current detection circuit 7 for detecting a DC current are connected to detect the start of the discharge lamp 5 and to control the subsequent start and rated lighting. The output signals of the DC voltage detection circuit 6 and the DC current detection circuit 7 are input to the lighting control circuit 8, which changes the oscillation frequency of the DC power supply 1 or the duty ratio thereof based on these signals. The lighting operation of is controlled.

Next, the operation of the above configuration will be described. When the DC power supply 1 is turned on, the inverter circuit 2 oscillates at a low frequency of about 400 Hz at which the problem of acoustic resonance does not occur, and the DC voltage detection circuit 7 detects the output voltage of the DC power supply 1, and this voltage is When a predetermined voltage for starting is reached, the lighting control circuit 8 receives the output of the DC voltage detecting circuit 7 and operates the starting circuit 4 to apply the starting voltage to the discharge lamp 5.
The discharge lamp 5 is started by this starting voltage, and when a current flows through the discharge lamp 5, the voltage across the discharge lamp 5 decreases, and the output voltage of the DC power supply 1 also decreases. By detecting this voltage drop by the DC voltage detection circuit 6, the start of the discharge lamp 5 is detected, and the operation of the start circuit 4 is stopped. After the discharge lamp 5 starts, the output of the DC power supply 1 is controlled by the lighting control circuit 8 according to the turn-off time and the turn-on time. The longer the turn-off time, the larger the output immediately after the start. It will be smaller and light up soon.

FIG. 2 is a circuit diagram showing a main part of the DC power supply 1. 2, a DC power supply 1 includes a series circuit of a flyback transformer 10 connected to a battery 9 and a transistor 11, and a series circuit of a diode 12 and a capacitor 13 connected to a secondary winding of the flyback transformer 10. And a flyback type DC / DC converter. Both ends of the capacitor 13 are outputs of the DC power supply 1, and reference numerals 6 and 7 correspond to the DC voltage detection circuit and the DC current detection circuit in FIG. A control circuit 14 controls the output of the DC power supply 1. The control circuit 14 includes a switching regulator control IC 15, a buffer circuit 16, and a set voltage circuit.
The outputs of the DC voltage detection circuit 6 and the DC current detection circuit 7 are connected to the positive input of the error amplifier EA1 and the negative input of the error amplifier EA2 of the IC 15, respectively.
The output of 18 is the negative input of the error amplifier EA1, the error amplifier EA
The oscillation outputs E1 and E2 of the IC 15 are input to the gate of the transistor 11 via the buffer circuit 16. As a result, when the battery 9 is turned on, a current flows through the flyback transformer 10 by switching of the transistor 11, a voltage is generated in the secondary winding, rectified by the diode 12, smoothed by the capacitor 13, and Is output. At this time, the output voltage and the output DC are detected by the DC voltage detection circuit 6 and the DC current detection circuit 7, and are set by the error amplifiers EA1 and EA2.
The duty ratio of the oscillation outputs E1 and E2 is controlled so that the voltage and the current do not exceed the set levels. Thereby, the output of the DC power supply 1 is stabilized at the lower value of the set values of the voltage and the current.

FIG. 3 is a circuit diagram showing a main part of the inverter circuit 2. In FIG. 3, the inverter circuit 2 has a configuration of a bridge inverter composed of four transistors Q1, Q2, Q3, and Q4 in order to supply a rectangular wave AC current to the discharge lamp 5 via the starting circuit 4. Reference numeral 19 denotes an oscillator which oscillates at a frequency of 400 Hz and outputs a two-phase clock signal which is alternately turned on to the drive circuit 20. Drive circuit
Reference numeral 20 denotes a circuit for receiving the output of the oscillation circuit 19 and driving the bridge inverter.
A pair of switching transistors Q1, Q4 and Q2, Q3, which are connected to the gates of Q2, Q3, Q4 and obliquely oppose each other, such that when one Q1, Q4 is simultaneously turned on, the other Q2, Q3 is simultaneously turned off. It is configured.

FIG. 4 is a circuit diagram showing a main part of the starting circuit 4. 4, a starting circuit 4 includes a pulse transformer 21 having a secondary winding connected to the output of the inverter circuit 2 and a transistor 22 connected to a primary winding of the pulse transformer 21.
, An oscillator 23 that starts oscillating in response to the control signal b from the lighting control circuit 8, and a buffer circuit 24 that switches the transistor 22 by the output of the oscillator 23. . Pulse transformer
The discharge lamp 5 is connected to the other end of the secondary winding 21 and receives the control signal b from the lighting control circuit 8 to start the discharge lamp 5 by a high-voltage pulse generated in the secondary winding.

FIG. 5 is a circuit diagram showing a main part of the lighting control circuit 8. As shown in FIG. In FIG. 5, the lighting control circuit 8 includes a DC power source 1.
Lighting judgment circuit for judging lighting of the discharge lamp 5 by receiving the output of the DC voltage detection circuit 6a for detecting the output voltage VDC
25, the output of the DC voltage detection circuit 6b for detecting the output VDC of the DC power supply 1, the output of the DC current detection circuit 7, and the output of the starting power signal circuit 29 to be described later, to the error amplifier EA2 of the IC 15 of the DC power supply 1. A power control circuit 26 for inputting a signal to control the output power of the DC power supply 1; a light-off time circuit 27 for receiving the output of the light-on discrimination circuit 25 and outputting a larger signal as the light-off time is longer; A start-up power signal setting trigger circuit 28 that triggers the output of the turn-off time circuit 27 when the discharge lamp 5 is turned on in response to the output, and the power immediately after the discharge lamp 5 starts in response to the output of the turn-off time circuit 27 After the level is set, the starting power signal circuit 29 outputs a signal for reducing the starting power level to the power control circuit 26 over time, and the input voltage of the starting power signal circuit 29 is reset when starting the discharge lamp. That a reset circuit 35, a starting power calculation circuit 100 for calculating the starting power corresponding to the output voltage of the DC power source 1 corresponding to the lamp voltage, constant switching circuit when switching the reduction time constant of starting power at a given lamp voltage
108. The turn-off time circuit 27 and the starting power signal setting trigger circuit 28 constitute starting initial power setting means.

The lighting determination circuit 25 outputs the output voltage V of the DC power supply 1.
Output voltage and setting of DC voltage detection circuit 6a for detecting DC
Comparing the output voltage of the circuit 31 with the comparator COMP1
If the output voltage of DC power supply 1 is higher than a predetermined voltage, LO
W, when the voltage is lower than the predetermined voltage, the HIGH control signal b
Output. This control signal b enters the oscillator 23 of the starting circuit 4.
When activated, a start pulse is generated when LOW. Also
When the control signal b is LOW, it is input to the power control circuit 26
The output of the DC voltage detection circuit 6b is output by the transistor Q6.
Short-circuit and set the output of the operational amplifier OP1 to 0V,
Even if the height increases, a large current can flow. This
As a result, while the starting pulse is being generated, the DC power supply 1
Operate the error amplifier EA1 in IC15 to make DC voltage
To a constant voltage required for starting. Also, the control signal b
Is low, the transistor Q9 of the reset circuit 35
Turns on, the voltage of the capacitor C29 of the starting power signal circuit 29
V _c29 Reset.

When the discharge lamp 5 starts, a large DC current flows and the DC voltage decreases, and the control signal b, which is the output of the lighting determination circuit 25, becomes HIGH. Therefore, the operation of the starting circuit 4 stops, and the starting pulse stops. Further, the transistor Q6 of the power control circuit 26 is turned off, and the output of the DC voltage detection circuit 6b becomes valid in the power control circuit 26. Inputs the output V _6b of the DC voltage detecting circuit 6b, starting power calculation circuit 100 decreases the output signal with the increase of the lamp voltage is less than a predetermined lamp voltage, the predetermined lamp voltage or the output signal to zero.

FIG. 6 shows the input voltage V of the starting power calculation circuit 100.
FIG. 6 is a diagram showing a relationship between _6b and an output voltage _Vc29 . Resistance R10
1, a bias voltage is applied by R102, and an operational amplifier OP
5, the signal is inverted and amplified. When the input voltage is equal to or higher than the input voltage V _6b ′ shown in FIG. 6, the output is set to 0 V by the diodes 106 and 107. Thus, the higher the lamp voltage, the lower the starting power.

When the control signal b becomes HIGH, the starting power signal setting trigger circuit 28 turns on the transistor Q7 for the time determined by the capacitor C28 and the resistor R28.
N, and outputs a trigger signal that makes the output of the starting power signal setting trigger circuit 28 become 0V. Note that the starting power signal setting trigger circuit 28 outputs a control signal b which is an output of the lighting determination circuit 25.
The trigger signal is output upon receipt of the signal. However, the trigger signal may be output upon detecting the DC power supply 1 being turned on. Alternatively, the trigger signal may be output after the DC power supply 1 is turned on until the lamp is turned on. It is good if it is between.

In the turn-off time circuit 27, the control signal b is received and integrated by the resistor R27 and the capacitor C27. The integrated output is output through the buffer amplifier OP2, and the output of the bias circuit 32 and the starting power signal setting trigger are output by the operational amplifier OP3. The output from the circuit 28 is added, inverted, amplified, and output. Since the output of the starting power signal setting trigger circuit 28 is normally HIGH, the output of the operational amplifier OP3 is negative and does not affect the starting power signal circuit 29 due to the presence of the diode 33. When the output of the operational amplifier OP2 becomes 0V, the operation of the bias circuit 32 that outputs a negative bias voltage and the operational amplifier OP3 causes the operational amplifier OP3 to output a higher voltage as the output voltage of the operational amplifier OP2 decreases as the output voltage of the operational amplifier OP2 decreases. That is, the output voltage of the light-off time circuit 27 can be increased as the light-off time becomes longer and the voltage of the integrating circuit of R27 and C27 becomes lower.

The starting power signal circuit 29 charges the capacitor C29 with the higher voltage in response to the output of the starting power calculation circuit 100 and the output of the turn-off time circuit 27, and supplies this voltage to the power supply via the buffer amplifier OP4. Output to the control circuit 26. Since the lamp voltage is low immediately after the start of the capacitor C29 after the light-off time is long, the output voltage of the starting power calculation circuit 100 is set to be high at this time. At this time, since the light-off time is long, the output voltage of the light-off time circuit 27 also increases.
The output voltage of 0 is set to be higher. When the turn-off time is short, the lamp voltage remains high. At this time, the output of the starting power calculation circuit 100 is low. Even in such a case, the output of the light-off time circuit 27 is equal to or more than a predetermined value,
Further, the longer the light-off time, the larger the value.

In this way, when the output of the starting power calculation circuit 100 is small due to the short turn-off time,
The power is controlled by the output of the turn-off time circuit 27 through the starting power signal circuit 29 and the power control circuit 26, and the starting power according to the turn-off time can be input to the discharge lamp. When the output of the starting power calculation circuit 100 is larger than that of the turning-off time circuit 27 due to the long light-off time, the starting power calculation circuit 100
The power is controlled via the starting power signal circuit 29 and the power control circuit 26 by the output of, and the starting power according to the lamp voltage can be input to the discharge lamp.

FIG. 7 is a characteristic diagram of lamp voltage (V) -lamp power (W). In FIG. 7, a large lamp power is obtained at a predetermined lamp voltage V 'or less, which is a starting region of the lamp, and this lamp power is input. Is controlled to be input. Therefore, the lamp power can be reliably controlled, the lamp can be stably lit quickly by inputting a large lamp power at the time of starting, the lamp power can be made substantially constant during the stable lighting, and the lamp can be lit at the rated lamp power.

Immediately after starting, the output voltage is output from the starting power calculation circuit 100 or the turn-off time circuit 27, and the capacitor C29 is charged. Thereafter, the capacitor C29 is discharged by the resistor R29 and gradually decreases as time elapses. Therefore, the output of the starting power signal circuit 29 gradually decreases. In addition, the time constant switching circuit
According to 108, the time constant is switched so that the time constant of the decrease in the lamp power is increased when the lamp voltage exceeds a predetermined voltage. That is, when the lamp voltage is higher than the predetermined voltage, the output of the DC voltage detection circuit 6b and the resistance R
The comparator COMP2 compares the voltage determined by 109 and R110.
By turning off the transistor Q8 and releasing the resistor R111, the discharge time constant is increased. As described above, by increasing the time constant when the lamp voltage becomes equal to or higher than the predetermined voltage, the lamp power is further reduced as shown by a dashed line in FIG. After the output, it is possible to shift to stable lighting without a large change.

The output of the starting power signal circuit 29 is input to the power control circuit 26, and the output of the DC current detecting circuit 7, the output of the setting voltage circuit 18, and the DC voltage detecting circuit 6b for detecting the output voltage VDC of the DC power supply 1. Are inverted and amplified by the operational amplifier OP1, and the outputs are input to the negative input terminal of the error amplifier EA2 of the IC 15 via the respective resistors. The error amplifier EA2 of the control circuit 14 shown in FIG. 2 is an example of a circuit in which the output of the set voltage circuit 18 and the output of the DC current detection circuit 7 are input. In 26, a circuit is added to enable power control. By doing so, the power can be controlled by changing the ON duty ratio of the transistor 11 of the DC power supply 1 so that the current input to the negative input terminal of the error amplifier EA2 becomes zero by these four signals.

The output of the DC current detection circuit 7 shown in FIG.
By inputting the output obtained by inverting and amplifying the divided output of the DC power supply 1 by the operational amplifier OP1 in addition to the output of the setting voltage circuit 18, a negative signal corresponding to the DC current and a negative signal corresponding to the DC voltage are added. The positive result is a positive setting voltage circuit.
The output voltage of the DC power supply 1 is controlled to be approximately constant power in a certain current / voltage range, and the power input to the discharge lamp 5 via the inverter circuit 2 is also constant. be able to.

Further, by inputting the output of the starting power signal circuit 29, the DC voltage detecting circuit 6 corresponding to the lamp voltage at the time of starting is compared with the rated power determined by the set voltage circuit 18.
The output of the starting power calculation circuit 100 in accordance with the output of b or the output of the turn-off time circuit 27 in accordance with the turn-off / turn-on time, whichever is greater, is used so that the lower the lamp voltage or the longer the turn-off time, the longer the turn-on time Is shorter, the larger the starting power, the more the starting power can be supplied to the discharge lamp 5, and the larger the power, the more the power is input to the discharge lamp 5 according to the lamp voltage or the time of turning off / on and the light output is started up quickly. As the time elapses, the lamp power is gradually approached to the rated power to control the lamp to perform the rated lighting, thereby preventing an excessive light output.

Here, the signal corresponding to the DC current and the signal corresponding to the DC voltage are added, and the result is controlled so as to be a predetermined value, so that the lighting can be performed approximately at a predetermined power. Needless to say, power can be more accurately controlled by lighting with a predetermined power by multiplying a signal according to a DC current and a signal according to a DC voltage and controlling the result to a predetermined value. Nor.

The control characteristics of the starting power calculation circuit 100 and the time constants of the light-off time circuit 27, the starting power signal circuit 29, and the time constant switching circuit 108 are such that the light output rises quickly and the light output after the start increases. It goes without saying that you need to choose not to be too much.

In the above embodiment, a flyback type DC / DC converter has been described as an example of a DC power supply.
Another DC power supply such as a converter may be used, and the inverter circuit may be another type of inverter such as a half-bridge type or a push-pull type.

In the above embodiment, the DC power supply 1
However, it is needless to say that the output of the lamp current supply means may be controlled irrespective of these configurations.

Further, in the above embodiment, the example of the rectangular wave lighting device having a low frequency has been described. However, the present invention is not limited to this, and if the discharge lamp does not cause harmful phenomena such as electrophoresis and acoustic resonance. Other lighting devices such as a high-frequency lighting device and a DC lighting device may be used.

[0041]

As described above, according to the present invention, when the lamp voltage detecting means detects a low lamp voltage in the starting region of the discharge lamp, the output of the lamp current supplying means is controlled to increase the lamp power. When a high lamp voltage is detected, the output of the lamp current supply means is controlled to supply a small amount of lamp power. Therefore, the lamp power can be reliably controlled, and the lamp can be lit at the rated lamp power during stable lighting.

[0042]

The lamp power calculating means includes a lamp power calculating means for reducing the output signal with an increase in the lamp voltage when the lamp voltage is lower than a predetermined lamp voltage, and reducing the output signal to 0 when the lamp voltage is higher than the predetermined lamp voltage. And the output of the lamp current supply means is controlled by the sum output of the bias means and the lamp. Therefore, in the lamp starting region, when the lamp voltage is lower than a predetermined lamp voltage, a large lamp power at the time of starting is inputted to quickly increase the luminous flux of the discharge lamp. When the lamp voltage is equal to or higher than a predetermined lamp voltage, the lamp is lit at the rated power.

When the lamp voltage exceeds a predetermined voltage, the time constant is switched by the time constant switching means so as to increase the lamp power reduction time constant in the lamp power calculation means. Since the rated lighting is gradually changed, the light output can be shifted to the stable lighting without a large change after the light output is set to the rated output after the start.

Further, the initial lamp power is set so that at least immediately after starting and restarting, a predetermined lamp power larger than the lamp power during stable lighting is supplied. Even in the case where the lamp is near, by inputting a large lamp power, even if the encapsulating metal adheres to the tube wall of the lamp when the lamp is turned off, a light output close to the time of stable lighting can be obtained immediately after the restart.

Further, the initial lamp power is set so that at least a predetermined lamp power larger than the lamp power at the time of stable lighting is inputted immediately after the start and restart according to the output of the light-off time detecting means, and the light-off time is short. By setting the initial lamp power to be longer when the lamp is longer than when the lamp is turned off, when the turn-off time is short, the luminous efficiency does not decrease because the vapor pressure of the sealed metal does not decrease, and the lamp is sealed. In such a case, a large amount of lamp power is not supplied at restart because the degree to which the metal adheres to the tube wall is low.In contrast, as the lighting time increases, the vapor pressure decreases and the enclosed metal adheres to the tube wall. In this case, a large lamp power can be input at the time of restart, so that a light output close to the time of stable lighting can be obtained immediately after restart.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a basic configuration of a discharge lamp lighting device according to one embodiment of the present invention.

FIG. 2 is a circuit diagram showing a main part of a DC power supply in the discharge lamp lighting device according to one embodiment of the present invention.

FIG. 3 is a circuit diagram showing a main part of an inverter circuit in the discharge lamp lighting device according to one embodiment of the present invention.

FIG. 4 is a circuit diagram showing a main part of a starting circuit in the discharge lamp lighting device according to one embodiment of the present invention.

FIG. 5 is a circuit diagram showing a main part of a lighting control circuit in the discharge lamp lighting device according to one embodiment of the present invention.

FIG. 6 is a characteristic diagram of a starting power calculation circuit in the lighting control circuit.

FIG. 7 is a lamp voltage-lamp power characteristic diagram of the lighting control circuit.

[Explanation of symbols]

 Reference Signs List 1 DC power supply 2 Inverter circuit 3 Lamp current supply means 4 Starting circuit 5 Discharge lamp 6, 6a, 6b DC voltage detecting circuit 7 DC current detecting circuit 8 Lighting control circuit 25 Lighting discriminating circuit 26 Power control circuit 27 Lighting time circuit 28 Starting power Signal setting trigger circuit 29 Starting power signal circuit 35 Reset circuit 100 Starting power calculation circuit 108 Time constant switching circuit

──────────────────────────────────────────────────の Continued on the front page (72) Inventor Shigeru Horii 1006 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Nobuhisa Yoshikawa 1006 Kadoma, Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. Kazuhiko Ito 1006 Kazuma Kazuma, Kadoma City, Osaka Prefecture (72) Inside Matsushita Electric Industrial Co., Ltd. 1006 Kadoma, Ichidai-shi Matsushita Electric Industrial Co., Ltd. (56) References JP-A-4-141988 (JP, A) JP-A-62-246297 (JP A) JP-A-3-77300 (JP, A) JP-A-60-250599 (JP, A) JP-A-3-138894 (JP, A) JP-A-2-136343 (JP, A) JP-A-3 JP-A-4-163887 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H05B 41/14-41/29 H02M 7/48

Claims (4)

(57) [Claims] 1. A lamp current supply means, a discharge lamp connected to the lamp current supply means, a lamp voltage detection means for detecting a lamp voltage, a lamp current detection means for detecting a lamp current, and a lamp voltage detection means Power control means for controlling the lamp power in response to the output of the lamp current detection means, and lighting control means, wherein the lighting control means adjusts the output voltage of the lamp voltage detection means in a lamp starting area.
If the lamp voltage is lower than the specified lamp voltage,
In both cases, the output signal is reduced.
A lamp power calculating unit for setting a signal to 0; and a biasing unit.
The lamp current is calculated by adding the output of the
When the output of the supply means is controlled, the lamp current supply means is controlled to input a large lamp power to the discharge lamp when the lamp voltage is low, and when the lamp voltage is high, the lamp current supply means is controlled to reduce the lamp current supply means. A discharge lamp lighting device configured to input lamp power to a discharge lamp and to control the discharge lamp to perform rated lighting after a lamp starting region. The lighting control means includes a time constant switching means connected to the lamp power calculating means and operating at a predetermined lamp voltage. When the lamp voltage becomes equal to or higher than the predetermined voltage, the lamp power calculating means controls the lamp power. Claims that are configured to switch the time constant so as to increase the time constant of decrease with respect to
2. The discharge lamp lighting device according to 1. 3. A lamp current supply means, a discharge lamp connected to the lamp current supply means, a lamp voltage detection means for detecting a lamp voltage, a lamp current detection means for detecting a lamp current, and a lamp voltage detection means. And the output of the lamp current detection means
Power control means for controlling the lamp power and lighting control means. The lighting control means controls the output voltage of the lamp voltage detection means in a lamp starting area.
At least during stable lighting immediately after starting and restarting.
Make sure that the specified lamp power is larger than the lamp power.
A starting initial power setting means for setting the initial lamp power is provided.
The lamp according to the set initial lamp power and lamp voltage.
High starting power and high lamp voltage when lamp voltage is low
When discharging large lamp power with small starting power
Input to the lamp and define the discharge lamp after the lamp starting area.
A discharge lamp lighting device configured to be controlled so as to be lit. 4. The starting initial power setting means includes: a light-off time detecting means for detecting a lamp light-off time; and a power which is at least larger than a lamp power at a time of stable lighting immediately after starting and restarting according to an output of the light-off time detecting means. A starting power signal setting trigger unit that can set an initial lamp power so that a larger lamp power flows as the turn-off time is longer is provided, and the lighting control unit is configured to select one of a starting power corresponding to the turning-off time and a starting power corresponding to the lamp voltage. 4. The discharge lamp lighting device according to claim 3 , wherein the lamp power is input to the discharge lamp, and control is performed such that the discharge lamp is operated at rated light after the lamp starting region.