JP2000068090A - Discharge lamp lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform lighting without giving the sensation incongruity in vision of a person, who is using a discharge lamp by dividing the time constant of the frequency change during the transition from the preheating frequency to the rated lighting frequency into two stages, setting the time constant of a first stage long, and making the time constant of a second stage smaller than that of the first one. SOLUTION: When a dimming switch is turned on, a first frequency shift in finished, and a transistor 19 is switched off simultaneously with the switching- off of a transistor 17, whereby a transistor 20 is switched on, the electric current flows to resistances 9a, 9b of the same time with the finish in the first frequency shift, and the frequency directly reaches the dimming lighting frequency by a second frequency shift determined by the resistances 9a, 9b. Accordingly, the frequency can be directly transferred to the dimming lighting frequency after the first frequency shift, and there is hardly time lag is hardly. That is, the frequency reaches directly the dimming lighting frequency from the frequency shift, so that the changes in frequency and luminous flux do not seem unnatural.

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 lighting a discharge lamp at a high frequency using an inverter circuit.

[0002]

2. Description of the Related Art FIG. 8 is a circuit diagram of a conventionally known discharge lamp lighting device. 1 is a DC power supply, 2 is an inverter circuit for converting an input from the DC power supply to a high-frequency output, 3 is a driver circuit for driving the inverter circuit, and 4 is a discharge lamp 7a and 7b connected to an output terminal of the inverter circuit ( The load circuit, 5 is a coupling capacitor, 6a and 6b are ballast coils, 8
a and 8b are starting capacitors. 9a, 9b and 9
c is a resistor, 9a determines the preheating frequency, rated lighting frequency and dimming lighting frequency, 9b determines the preheating frequency and dimming lighting frequency, and 9c determines the preheating frequency.
Reference numeral 10 denotes a sequence circuit for controlling the oscillation frequency of the driver circuit 3, reference numeral 11 denotes a capacitor, reference numerals 12 and 16 denote comparators, each having a predetermined reference voltage value. Until this reference voltage value is exceeded, the output is Lo. When the voltage value is exceeded, the output becomes Hi. 13 is a timer circuit, 13a is a timer control power switch, 13b is a timer control power supply,
Reference numeral 18 denotes a dimming switch.

In the above-described discharge lamp lighting device, the inverter circuit 2 is driven by the driver circuit 3 and converts the DC power supply 1 into a high-frequency output. The high frequency output from the inverter circuit 2 turns on the lamps 7a and 7b via the coupling capacitor 5 and the ballast coils 6a and 6b. When the lamp is preheated before the start of discharge, current flows through the starting capacitors 8a and 8b. These lamps 7a and 7b
The starting capacitors 8a and 8b connected in parallel to the non-power supply side constitute a series resonance circuit with the ballast coils 6a and 6b together with the preheating of the lamps 7a and 7b, and are generated at both ends of the starting capacitors 8a and 8b. A voltage is applied to the lamps 7a and 7b to start the lamps 7a and 7b. The driver circuit 3 has, for example, a constant-voltage power supply therein, and assuming that the current from the constant-voltage power supply is i, the inverter circuit changes the oscillation frequency at a frequency of f = K × i (Hz) (K is a constant). The circuit 2 is driven.

Specifically, the timer circuit 13 is set so that the output of the comparator 12 becomes Lo when the discharge lamp is preheated, and becomes Hi after the discharge lamp is preheated. The voltage of the constant voltage power supply in the driver circuit 3 is V1,
The resistance value of the resistor 9a is R1, the resistance value of the resistor 9b is R2, and the resistor 9 is
Assuming that the resistance value of c is R3, the preheating frequency f1 at the time of lamp preheating is determined by the resistance values R1 to R3 of these resistors, and f1 = K × (V1 / R1 + V1 / R2 + V1 / R3). After the preheating of the lamp is completed, the output of the timer circuit 13 exceeds a predetermined reference voltage value, the output of the comparator 12 becomes Hi, and the capacitor 11 is charged. Therefore,
Rated lighting frequency f2 when dimming switch 18 is OFF
Is determined by the resistance value R1 of the resistor 9a, and f2 = K × (V1 / R1). Further, the dimming lighting frequency f3 when the dimming switch 18 is ON is determined by the resistance values R1 and R2 of the resistors 9a and 9b, and f3 = K × (V1 / R1 + V1 / R2).

At this time, if the capacitance of the capacitor 11 is C1, the frequency changes from f1 to f2 with a time constant of τ = R3 × C1. As a result, the frequency after the timer control power switch 13a is turned on changes in an integral curve of the time constant τ as shown in FIG. Further, the luminous flux of the lamp changes as shown in FIG. 9 due to the change of the frequency. When the dimming switch 18 is ON, the dimming signal becomes valid after the frequency reaches the rated lighting frequency f2, and the output of the comparator 16 switches from Hi to Lo. Therefore,
The frequency change during dimming is as shown in the rated lighting frequency f2
And reaches the dimming lighting frequency f3.

In the case of a device having a dimming function, if the dimming signal is made effective during the shift of the frequency, the frequency and the luminous flux change unnaturally, giving a sense of incongruity to the user. That is, the frequency shifts as the capacitor 11 is charged, and the capacitance C1 of the capacitor 11 is changed.
Therefore, the time constant changes from f1 to f2 with a time constant of τ = R3 × C1. If the dimming signal becomes valid during this shift, the resistance 9
Current also flows through b. Therefore, the current flows through all of the resistors 9a, 9b, and 9c, so that the frequency becomes
Until the battery 1 is charged, the voltage is momentarily lowered, so that the change of the luminous flux becomes unnatural as shown in FIG. Therefore,
The dimming signal cannot be enabled until it is completely in the all-light state.

[0007]

In the conventional discharge lamp lighting device which operates as described above, the time constant τ of the change from the preheating frequency f1 to the rated lighting frequency f2 is τ = R3 × C1, and the resistance 9c Resistance R3, the capacitance C of the capacitor 11
Determined by 1. However, the resistance value R3 of the resistor 9c determines the preheating frequency and has a small degree of freedom, and the slope of the time constant τ is substantially determined by the capacitance C1 of the capacitor 11. However, when C1 is large, the time constant becomes large and the slope of the frequency shift becomes gentle, so that it takes a considerable time from the preheating frequency f1 to reach the rated lighting frequency f2. For those with a dimming function, if the dimming signal is enabled during the frequency shift,
Since the change in the frequency and the luminous flux becomes unnatural as shown in FIG. 10, it gives a sense of incongruity to the user, and the dimming signal cannot be made effective until the light enters the full light state. Therefore, it is not possible to shift to the dimming state without passing through the all-light state, so that a considerable time is required until the dimming state is reached.

On the other hand, when the capacitance C1 of the capacitor 11 is reduced, the slope of the frequency shift becomes steep, and a predetermined all-light or dimming output state is obtained in a short time. In some cases, the abnormal lamp detection circuit that determines the start of lamp discharge may not be able to follow the frequency change, and may operate at a low frequency even if an abnormality has occurred. Becomes

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem. The time constant of the frequency change during the transition from the preheating frequency to the rated lighting frequency or the dimming lighting frequency is set to two steps. By increasing the time constant of the first stage and making the time constant of the second stage smaller than the time constant of the first stage, and after starting the discharge of the lamp, shifting from the time constant of the first stage to the time constant of the second stage, An object of the present invention is to provide a discharge lamp lighting device capable of reaching a rated lighting frequency and having a dimming function, directly reaching the dimming lighting frequency, and lighting without giving a sense of strangeness to a user.

[0010]

SUMMARY OF THE INVENTION The present invention provides an inverter circuit for converting a DC input to a high-frequency output, a discharge lamp load circuit connected to an output terminal of the inverter circuit, a driver circuit for driving the inverter circuit, and power-on. Control means for causing the oscillating frequency of the driver circuit to reach the rated lighting frequency, wherein the control means sets the oscillating frequency of the driver circuit at a first time constant after the end of preheating of the discharge lamp. Means for reducing the discharge, and
Means for causing the oscillation frequency of the driver circuit to reach the rated lighting frequency with a second time constant smaller than the above time constant.

Further, the present invention provides an inverter circuit for converting a DC input to a high-frequency output, a discharge lamp load circuit connected to an output terminal of the inverter circuit, a driver circuit for driving the inverter circuit, and the driver circuit after power-on. Control means for causing the oscillating frequency to reach a rated lighting frequency or a dimming lighting frequency greater than the rated lighting frequency, the control means comprising: after the preheating of the discharge lamp,
Means for lowering the oscillation frequency of the driver circuit with a first time constant, and after starting discharge of the discharge lamp, increasing the oscillation frequency of the driver circuit with a second time constant smaller than the first time constant to a rated lighting frequency or dimming lighting Means for reaching the frequency.

The control means includes an integrating circuit comprising a resistor and a first capacitor; first switching means connected between a contact between the resistor and the first capacitor; and ground; A second switch connected between the terminal and the ground, and a second capacitor connected in parallel to the second switch, wherein the first time constant is equal to the value of the first switch. The second time constant is an integration curve determined by an integration circuit consisting of a resistor and a first capacitor using the first and second switching means. This is an integration curve determined by an integration circuit including a second capacitor having a small capacitance.

The present invention also provides an inverter circuit for converting a DC input to a high-frequency output, a discharge lamp load circuit connected to an output terminal of the inverter circuit, a driver circuit for driving the inverter circuit, and the driver circuit after power-on. Control means for causing the oscillation frequency of the discharge lamp to reach the rated lighting frequency, wherein the control means reduces the oscillation frequency of the driver circuit by a first time constant after the preheating of the discharge lamp is completed. And means for causing the oscillation frequency of the driver circuit to reach the rated lighting frequency stepwise after the discharge lamp starts discharging.

The present invention also provides an inverter circuit for converting a DC input to a high-frequency output, a discharge lamp load circuit connected to an output terminal of the inverter circuit, a driver circuit for driving the inverter circuit, and the driver circuit after power is turned on. Control means for causing the oscillating frequency to reach a rated lighting frequency or a dimming lighting frequency greater than the rated lighting frequency, the control means comprising: after the preheating of the discharge lamp,
Means for lowering the oscillation frequency of the driver circuit with the first time constant, and means for causing the oscillation frequency of the driver circuit to reach the rated lighting frequency or the dimming lighting frequency stepwise after the discharge lamp starts discharging. It is.

The above-described discharge lamp lighting device includes a discharge detection circuit for detecting that the discharge lamp has started discharging, and when the discharge detection circuit detects discharge, the oscillation frequency of the driver circuit is determined by a second time constant. To the lighting frequency or the dimming lighting frequency.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a circuit diagram of a discharge lamp lighting device according to Embodiment 1 of the present invention. 1 is a DC power supply, 2 is an inverter circuit for converting a DC input into a high frequency output, and 3 is a driver circuit for driving the inverter circuit. Reference numeral 4 denotes a lamp load circuit connected to the output terminal of the inverter circuit, and includes a coupling capacitor 5, ballast coils 6a and 6b, lamps 7a and 7b, and starting capacitors 8a and 8b. 9a, 9b, 9c and 14 are resistors, 9a determines a preheating frequency, a rated lighting frequency and a dimming lighting frequency, 9b determines a preheating frequency and a dimming lighting frequency, and 9c determines a preheating frequency.
The resistor 14 is unnecessary for turning on the light, but is connected to discharge the charge of the capacitor 15 when turning off the light. Accordingly, if the resistance values of the resistors 9c and 14 are R3 and R4, respectively, R4 is sufficiently smaller than R3.

Reference numeral 10 denotes a sequence circuit for controlling the oscillation frequency of the driver circuit 3, and reference numerals 11 and 15 denote capacitors.
Assuming that the capacitance value of the capacitor 15 is
Is sufficiently smaller than the capacitance value C1. Also, 12
And 16 are comparators having a predetermined reference voltage value. Until the reference voltage value is exceeded, comparators 12 and
The output of the comparator 16 is Lo, and the output of the comparators 12 and 16 becomes Hi when the output exceeds a predetermined reference voltage value. A timer circuit 13 has a timer control power switch 13a and a timer control power supply 13b. 17, 19 and 20 are transistors. Reference numeral 18 denotes a switch for enabling the dimming function.

The operation of FIG. 1 will be described with reference to the timing chart of FIG. The timer circuit 13 is set so that the output of the comparator 12 becomes Lo when the lamp is preheated, and becomes Hi after the lamp is preheated. Therefore, during the preheating period, the output of the comparator 12 is Lo, and no current flows through the capacitor 11, and a current flows from the resistor 9 c to the comparator 12. After the preheating of the lamp is completed, the output of the timer circuit 13 exceeds a predetermined reference voltage value, the output of the comparator 12 becomes Hi, the current flows to the capacitor 11, the capacitor 11 is charged, and the frequency of the first time constant is changed. The shift starts. or,
The reference voltage value of the comparator 16 is set such that the output of the comparator 16 is changed from Hi to Lo by the output from the timer circuit 13 after an appropriate time at which the lamps 7a and 7b can be discharged. At this time, the transistor 17 is turned on.
, The resistor 14 and the capacitor 15 that have become invalid become valid, and current flows through the capacitor 15. When the resistor 14 and the capacitor 15 become effective, the capacitor 15 is charged via the resistor 14, and the second time constant is τ = (R3 + R4) × ｛C1 × C2 / (C1 + C
2) The frequency is shifted by｝. Here, the resistance value R4 of the resistor 14 is sufficiently smaller than the resistance value R3 of the resistor 9c.
Since the capacitance C2 of the capacitor 15 is sufficiently smaller than the capacitance C1 of the capacitor 11, R3ＲR4, C1≫C
2 holds.

Therefore, the time constant of the frequency shift is quasi τ
≒ R3 × C2, and the frequency starts the second frequency shift with this time constant. When the charging of the capacitor 11 is completed, a current flows only through the resistor 9a, and the frequency is determined only by the resistance value R1 of the resistor 9a and reaches the rated lighting frequency f2. Therefore, when the dimming switch 18 is OFF, after the first frequency shift ends, the rated lighting frequency f2 is rapidly reached by the second frequency shift. In addition, lamps having means for checking the discharge state of the lamp and then shifting to the rated lighting frequency, such as lamp abnormality detection, can sufficiently determine the lamp state during the first frequency shift. It will be possible to design means for safe protection.

On the other hand, when the dimming switch is ON, the first frequency shift ends, the transistor 17 is turned off, and at the same time, the transistor 19 is also turned off. At the same time as the end of the frequency shift, a current flows through the resistors 9a and 9b, the frequency is determined by R1 and R2, and directly reaches the dimming lighting frequency f3 by the second frequency shift. Therefore, after the first frequency shift, it is possible to directly shift to the dimming lighting frequency without passing through the rated lighting frequency in the second frequency shift. Although the second frequency shift rapidly reaches the target value due to a very small time constant of τ ≒ R3 × C2, after the transistor 17 is turned off, the transistor 20 is turned on, and the capacitor 11 is completely charged. It is done at the same time and there is almost no time lag. Therefore, the second frequency shift and the turning on of the transistor 20 are performed simultaneously,
Even if the dimming lighting frequency f3 is directly reached by the second frequency shift and the dimming signal is enabled during the frequency shift, the frequency and the luminous flux do not unnaturally change, and the user's visual perception is uncomfortable. Without this, the problem as shown in FIG. 10 can be avoided.

When the transistor 20 is turned on before the capacitor 11 is charged, a current flows through all of the resistors 9a, 9b, and 9c until the capacitor 11 is completely charged. Although the frequency may be higher than the lighting frequency and the frequency may deviate from the dimming lighting frequency for a moment as shown in FIG. 3, since the transistor 20 is turned on and the capacitor 11 is charged almost simultaneously, the light output does not follow. In the same manner as described above, the problem shown in FIG. 10 can be avoided.

Further, the resistor 14 is unnecessary when the light is turned on, but when the light is turned off, the transistor 17 is switched from OFF to ON.
Therefore, it is connected to discharge the charge of the capacitor 15. Therefore, it is sufficiently smaller than the resistor 9c, and has little effect on lighting.

In the above description, the driver circuit has a constant voltage power supply inside, and has a positive characteristic with respect to the current flowing from the constant voltage power supply. However, the present invention is not limited to this, and the driver circuit has a negative characteristic. A driver circuit having characteristics, a characteristic having a positive characteristic or a negative characteristic with respect to an externally applied voltage, and various other driver circuits may be used.

Embodiment 2 FIG. 4 is a circuit diagram of a discharge lamp lighting device according to Embodiment 2 of the present invention. All the reference numerals in FIG. 4 are the same as those in the first embodiment, and a description thereof will be omitted. The circuit of the discharge lighting device of the present embodiment is obtained by removing the resistor 14 and the capacitor 15 from the circuit of the discharge lamp lighting device of the first embodiment. Therefore, the operation is such that the output of the comparator 16 becomes Lo and the transistor 17 is turned off.
F is the same as in the first embodiment of the present invention until the first frequency shift ends. Transistor 17 is OF
In the case of F, the end of the capacitor 11 is opened, charging is completed instantaneously, and the frequency shift reaches the rated lighting frequency or the dimming lighting frequency stepwise. Thus, in the first embodiment of the present invention, the second time constant
While the rated lighting frequency or the dimming lighting frequency is reached by the integration curve, in the present embodiment, there is no inclination and the rated lighting frequency or the dimming lighting frequency is reached stepwise. The changes in the frequency and the light output are as shown in FIG.

Embodiment 3 FIG. 6 is a circuit diagram of a discharge lamp lighting device according to Embodiment 3 of the present invention. 1 to 20 in FIG.
Is the same as that of the first embodiment, and the description is omitted. Reference numeral 21 denotes a lamp discharge detection circuit, which operates by detecting that the lamp has started discharging at the time of the first frequency shift and detecting a sharp drop in the lamp voltage when the lamp has started discharging. . In the first and second embodiments, the timing at which the output of the comparator 16 is switched is determined by specifying the time by connecting to the timer 13, but in the present embodiment, the discharge detection circuit 21 detects the discharge of the lamp. Is determined by detecting. That is, when the discharge detection circuit 21 detects the discharge of the lamp, the output of the comparator 16 changes from Lo to Hi, the capacitor 15 is charged, and the operation shifts to the second frequency shift, or the rated lighting frequency is changed stepwise. Or it reaches the dimming lighting frequency. Therefore, the timing chart of the third embodiment is as shown in FIG. As a result, it is possible to reach the rated lighting frequency or the dimming lighting frequency in a shorter time after the preheating of the lamp is completed.

In the above description, the lamp discharge detection circuit 21
Is a circuit for detecting that the lamp has started discharging at the time of the first frequency shift, and operates by detecting a sharp drop in the lamp voltage when the lamp has started discharging. However, the present invention is not limited to this, and the discharge of the lamp may be detected by another method.

[0027]

As is apparent from the above description, the discharge lamp lighting device according to the present invention includes an inverter circuit for converting a DC input to a high frequency output, and a discharge lamp load circuit connected to an output terminal of the inverter circuit. And a driver circuit for driving the inverter circuit, and control means for causing the oscillation frequency of the driver circuit to reach the rated lighting frequency after power is turned on, wherein the control means terminates preheating of the discharge lamp. Means for lowering the oscillation frequency of the driver circuit with a first time constant, and after the discharge lamp starts discharging, the oscillation frequency of the driver circuit reaches the rated lighting frequency with a second time constant smaller than the first time constant. And a means for causing the discharge lamp to reach the all-light state in a short time after the end of preheating of the discharge lamp. In addition, it is possible to reach the maximum output lighting frequency in a short time and safely deal with lamp abnormalities.

The present invention also provides an inverter circuit for converting a DC input to a high-frequency output, a discharge lamp load circuit connected to an output terminal of the inverter circuit, a driver circuit for driving the inverter circuit, and a driver circuit after power is turned on. Control means for causing the oscillating frequency to reach a rated lighting frequency or a dimming lighting frequency greater than the rated lighting frequency, the control means comprising: after the preheating of the discharge lamp,
Means for lowering the oscillation frequency of the driver circuit with a first time constant, and after starting discharge of the discharge lamp, increasing the oscillation frequency of the driver circuit with a second time constant smaller than the first time constant to a rated lighting frequency or dimming lighting Since means for reaching the frequency is provided, it is possible to reach the all-light state or the dimming state in a short time after the end of preheating of the discharge lamp. In addition, the lamp can reach the rated lighting frequency or the dimming lighting frequency immediately after the lamp discharge, and can safely cope with a lamp abnormality. Furthermore, since the dimming lighting frequency can be reached without passing through the rated lighting frequency, it is possible to realize lighting that does not make the user feel uncomfortable during dimming lighting.

The control means includes an integrating circuit comprising a resistor and a first capacitor; a first switch means connected between a contact between the resistor and the first capacitor and ground;
A second terminal connected between the terminal of the integrating circuit and the ground.
And a second capacitor connected in parallel to the second switch means, and the first time constant comprises a resistor and a first capacitor using the first switch means. An integration curve determined by an integration circuit,
Since the second time constant is an integration curve determined by an integration circuit including a resistor and a second capacitor using the first and second switch means, the switch means such as a capacitor, a resistor, a comparator, and a transistor is used. The above effects can be achieved with such a simple circuit configuration.

The present invention also provides an inverter circuit for converting a DC input into a high-frequency output, a discharge lamp load circuit connected to an output terminal of the inverter circuit, a driver circuit for driving the inverter circuit, and the driver circuit after power-on. Control means for causing the oscillation frequency of the discharge lamp to reach the rated lighting frequency, wherein the control means reduces the oscillation frequency of the driver circuit by a first time constant after the preheating of the discharge lamp is completed. And means for causing the oscillation frequency of the driver circuit to reach the rated lighting frequency stepwise after the discharge lamp starts discharging, so that the all-light state can be reached immediately after the preheating of the discharge lamp is completed. In addition, it is possible to reach the maximum output lighting frequency in a short time and safely deal with lamp abnormalities.

The present invention also provides an inverter circuit for converting a DC input to a high-frequency output, a discharge lamp load circuit connected to an output terminal of the inverter circuit, a driver circuit for driving the inverter circuit, and the driver circuit after power is turned on. Control means for causing the oscillating frequency to reach a rated lighting frequency or a dimming lighting frequency greater than the rated lighting frequency, the control means comprising: after the preheating of the discharge lamp,
Since there are provided means for lowering the oscillation frequency of the driver circuit with the first time constant and means for causing the oscillation frequency of the driver circuit to reach the rated lighting frequency or the dimming lighting frequency stepwise after the discharge lamp starts discharging. After the preheating of the discharge lamp, the all-light state or the dimming state can be reached instantaneously. In addition, the lamp can reach the rated lighting frequency or the dimming lighting frequency immediately after the lamp discharge, and can safely cope with a lamp abnormality. Furthermore, since the dimming lighting frequency can be reached without passing through the rated lighting frequency, it is possible to realize lighting that does not make the user feel uncomfortable during dimming lighting.

The above-described discharge lamp lighting device is provided with a discharge detection circuit for detecting that the discharge lamp has started discharging, and when discharge is detected by the discharge detection circuit, by a second time constant or stepwise. And to make the oscillation frequency of the driver circuit reach the lighting frequency or the dimming lighting frequency.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a discharge lamp lighting device according to a first embodiment of the present invention.

FIG. 2 is a timing chart showing a frequency shift and a change in optical output according to the first embodiment of the present invention.

FIG. 3 is a timing chart showing frequency shift and light output change in dimming lighting according to the first embodiment of the present invention.

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

FIG. 5 is a timing chart showing a frequency shift and a change in light output of the discharge lamp lighting device according to the second embodiment of the present invention.

FIG. 6 is a circuit diagram of a discharge lamp lighting device according to a third embodiment of the present invention.

FIG. 7 is a timing chart showing frequency shift and light output change of the discharge lamp lighting device according to the third embodiment of the present invention.

FIG. 8 is a circuit diagram showing an example of a conventional discharge lamp lighting device.

FIG. 9 is a timing chart showing an example of a conventional discharge lamp lighting device showing a frequency shift and a change in light output.

FIG. 10 is a timing chart showing a frequency shift and a change in light output of a conventional discharge lamp lighting device.

[Explanation of symbols]

Reference Signs List 1 DC power supply, 2 inverter circuit, 3 driver circuit, 4 load circuit, 9a, 9b, 9c, 14 resistor, 10 sequence circuit, 11, 15 capacitor, 12, 16 comparator, 13 timer circuit, 13a timer control power switch, 13b Timer control power supply, 17, 19, 20 transistors,
18 dimming switch, 21 lamp discharge detection circuit.

 ──────────────────────────────────────────────────の Continuing from the front page (72) Inventor, Atsushi Ishikawa 5-1-1, Ofuna, Kamakura-shi, Kanagawa F-term in Mitsubishi Electric Lighting Co., Ltd. (Reference) 3K072 AA02 AB02 BA03 BC01 BC03 DB03 DC02 EB01 EB05 GA02 GB12 GC04 HA06 HB03 3K098 CC01 CC07 CC44 CC62 DD22 DD37 EE14 EE16 FF03

Claims (6)

[Claims] 1. An inverter circuit for converting a DC input to a high-frequency output, a discharge lamp load circuit connected to an output terminal of the inverter circuit, a driver circuit for driving the inverter circuit, and an oscillation frequency of the driver circuit after power is turned on. And a control means for causing the discharge lamp to reach the rated lighting frequency.
Means for lowering the oscillation frequency of the driver circuit with the time constant of: and means for causing the oscillation frequency of the driver circuit to reach the rated lighting frequency with a second time constant smaller than the first time constant after the discharge lamp starts discharging. A discharge lamp lighting device, comprising: 2. An inverter circuit for converting a DC input into a high-frequency output, a discharge lamp load circuit connected to an output terminal of the inverter circuit, a driver circuit for driving the inverter circuit, and an oscillation frequency of the driver circuit after power is turned on. And a control means for reaching a rated lighting frequency or a dimming lighting frequency higher than the rated lighting frequency, wherein the control means controls the driver circuit with a first time constant after completion of preheating of the discharge lamp. Means for lowering the oscillation frequency and means for causing the oscillation frequency of the driver circuit to reach the rated lighting frequency or the dimming lighting frequency with a second time constant smaller than the first time constant after the discharge lamp starts discharging. Discharge lamp lighting device characterized by the above-mentioned. 3. The control means includes: an integrating circuit comprising a resistor and a first capacitor; first switching means connected between a contact between the resistor and the first capacitor; and ground; A second switch connected between the terminal and the ground, and a second capacitor connected in parallel to the second switch, wherein the first time constant is equal to the value of the first switch. The second time constant is determined by an integrating circuit consisting of a resistor and a first capacitor using a means.
3. The discharge lamp lighting according to claim 1, wherein the first and second switching means are determined by an integrating circuit including a resistor and a second capacitor having a smaller capacity than the first capacitor. apparatus. 4. An inverter circuit for converting a DC input into a high-frequency output, a discharge lamp load circuit connected to an output terminal of the inverter circuit, a driver circuit for driving the inverter circuit, and an oscillation frequency of the driver circuit after power-on. And a control means for causing the discharge lamp to reach the rated lighting frequency.
Means for lowering the oscillation frequency of the driver circuit with a time constant of: and means for causing the oscillation frequency of the driver circuit to reach the rated lighting frequency stepwise after the discharge of the discharge lamp is started. apparatus. 5. An inverter circuit for converting a DC input to a high-frequency output, a discharge lamp load circuit connected to an output terminal of the inverter circuit, a driver circuit for driving the inverter circuit, and an oscillation frequency of the driver circuit after power is turned on. And a control means for reaching a rated lighting frequency or a dimming lighting frequency higher than the rated lighting frequency, wherein the control means controls the driver circuit with a first time constant after completion of preheating of the discharge lamp. A discharge lamp lighting device comprising: means for lowering the oscillation frequency; and means for causing the oscillation frequency of the driver circuit to reach a rated lighting frequency or a dimming lighting frequency stepwise after the discharge lamp starts discharging. 6. A discharge detecting circuit for detecting that a discharge lamp has started discharging, wherein when a discharge is detected by the discharge detecting circuit, an oscillation frequency of the driver circuit is set to a lighting frequency or dimming by a second time constant. The discharge lamp lighting device according to claim 1, wherein the lighting frequency is reached.