JPH03110795A - Lighting device for discharge lamp - Google Patents

Abstract

PURPOSE:To prevent the falling off of the light output of discharge lamp in the rated lighting, the shortening of lifetime and breakdown or the like of circuit elements constructing lighting circuits by switching forcedly lighting modes of the discharge lamp to the dimmed lighting mode when the ambient temperature of the discharge lamp becomes higher than a specified value. CONSTITUTION:When the ambient temperature TA of a discharge lamp l is lower than a specified value TAT, a switching circuit II switches the lighting mode in a lighting circuit I to either one of the rated lighting mode or the dimmed lighting mode corresponding to the operation of a dimming switching III. When the ambient temperature TA of the lamp l becomes higher than a specified value TAT, the mode is switched forcedly to the dimmed lighting mode regardless of the state of the dimmer switch III. Thus, the temperature rise of the coolest point of the discharge lamp l in the rated lighting in a high ambient temperature TA can be suppressed. Thereby the falling off of the light output of the discharge lamp l, and the shortening of lifetime and breakdown or the like of circuit elements constructing lighting circuits can be prevented.

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention is applicable to outdoor use such as garden lights, etc.
The present invention relates to a discharge lamp lighting device for lighting a discharge lamp whose ambient temperature changes greatly, and particularly relates to a dimmable discharge lamp lighting device.

[Traditional techniques]

2. Description of the Related Art Various types of discharge lamp lighting devices having a dimmable configuration are conventionally known.

[Problem to be solved by the invention]

When a dimmable discharge lamp lighting device is used outdoors as a closed appliance, such as a garden lamp, the ambient temperature of the discharge lamp changes greatly depending on the season. As the ambient temperature changes in this way, the following problems become noticeable.

For example, if a discharge lamp is turned on at its rated value when the ambient temperature is high, such as in the summer, the temperature of the tube wall of the discharge lamp will rise, the light output will decrease, and the temperature of the circuit elements that make up the lighting circuit will rise significantly. As a result, the life of the circuit element will be shortened, and in the worst case, the circuit element will be destroyed.

Furthermore, if the discharge lamp is dimmed and lit when the ambient temperature is low, such as during winter, the discharge lamp may turn off as the ambient temperature falls, and may not be able to maintain its lighting.

A first object of the present invention is to provide a discharge lamp lighting device that can prevent a reduction in light output during rated lighting and shorten the lifespan and destruction of circuit elements constituting a lighting circuit when the ambient temperature is high. That's true.

A second object of the present invention is to provide a discharge lamp lighting device that can prevent the discharge lamp from going out during dimming lighting when the ambient temperature is low.

[Means to solve the problem]

As shown in FIG. 1, the discharge lamp lighting device according to claim (1) is characterized in that, as shown in FIG. It is configured to be switchable between the rated lighting mode and dimming lighting mode in response to the operation of the switch (■). A temperature detection circuit (2) is provided to detect the ambient temperature TA of the discharge lamp (1), and when the ambient temperature TA of the discharge lamp (1) exceeds a predetermined value TAN based on the output of the temperature detection circuit (2), the dimmer switch (2) is activated. The switching circuit (2) is configured to forcibly set the lighting mode of the discharge lamp (1) to the dimming lighting mode regardless of the state.

On the other hand, the discharge lamp lighting device according to claim (2) is provided with a temperature detection circuit (2) for detecting the ambient temperature TA of the discharge lamp l, and based on the output of this temperature detection circuit (2), the discharge lamp lighting device The switching circuit (2) is configured to forcibly change the lighting mode of the discharge lamp (1) to the rated lighting mode regardless of the state of the dimmer switch (2) when the ambient temperature TA of the discharge lamp (1) falls below a predetermined value TAL. The rest is the same as claim fl).

Note that the predetermined value TAL in claim (2) is, of course, a different value from the predetermined value TAN in claim (1), and T AL < T AN.

[For production]

According to the configuration described in claim (1), if the ambient temperature TA of the discharge lamp l is lower than the predetermined value TAN, the switching circuit (2) changes the lighting mode in the lighting circuit I to the rated lighting mode in response to the operation of the dimmer switch (2). and switch to either dimming lighting mode. However, the ambient temperature TA of the discharge lamp l
When becomes equal to or greater than a predetermined value T□, the dimming lighting mode is forcibly entered regardless of the state of the dimming switch ■. Therefore, when the ambient temperature TA is high, it is possible to suppress an increase in the temperature of the coldest point of the discharge lamp l during rated lighting, thereby reducing the light output of the discharge lamp l and shortening the life of the circuit elements constituting the lighting circuit. Destruction can be prevented.

According to the configuration described in claim (2), if the ambient temperature TA of the discharge lamp l is higher than a predetermined value, the switching circuit (2) changes the lighting mode in the lighting circuit I to the rated lighting mode and the rated lighting mode in accordance with the operation of the dimmer switch (2). Switch to one of the dimming lighting modes. However, when the ambient temperature TA of the discharge lamp 1 falls below a predetermined value, the rated lighting mode is forcibly set regardless of the state of the dimmer switch (2). Therefore, the ambient temperature TA
It is possible to prevent the discharge lamp l from extinguishing during dimming lighting when the amount of light is low.

Note that the configuration described in claim (1) and the configuration described in claim (2) can also be combined.

FIG. 2 is a diagram schematically showing the operation of a discharge lamp lighting device that combines the configuration described in claim (1) and the configuration described in claim (2). This figure shows that the ambient temperature TA is TAL≦TA
In the range of ≦T□, the discharge lamp E can be lit in either the rated lighting mode or the dimming lighting mode, and in the range of TA>TA, l, the discharge lamp I can be lit only in the dimming lighting mode. This shows that in the range of TA<TAL, the discharge lamp I can be lit only in the rated lighting mode.

Note that in the configuration described in claim (1), there is no restriction based on the predetermined value TAL. Further, in the configuration described in claim (2), there is no restriction based on the predetermined value T□.

In addition, regarding the dimming mode, not only - level dimming,
It may be possible to perform multi-stage dimming of two or more stages or continuous dimming.

Further, E is a DC power supply that supplies power to the lighting circuit (2), and includes a DC power supply obtained by rectifying an AC power supply, and a DC power supply obtained by further smoothing the AC power supply.

〔Example〕

A first embodiment of a discharge lamp lighting device according to the invention recited in claim 1 will be described with reference to FIGS. 3 and 4. FIG.

In Fig. 3, 1 is a single-stone inverter circuit, with a switching element Q1 consisting of a transistor, and a capacitor C1.
, choke coil L, , L2. It is composed of current transformer CT, etc. 2 is a cutoff circuit, which includes diodes D2. Resistance R,,R2,R9゜R,. , ) consists of a transistor Q2. 3 is a timer circuit, which includes a comparator CP1, a transistor Q3 . Q4. It is composed of resistors R, , R3-R7, capacitors C3 and C4, and Zener diode ZD.

The above circuit corresponds to the lighting circuit I in FIG.
59196), the operation will be briefly explained.

In the inverter circuit 1, the switching element Q1 repeatedly turns on and off, so that the capacitor C1 and the choke coil L
, , L2, high frequency power is supplied to the discharge lamp l via the resonant circuit consisting of the resonant circuit.

In the timer circuit 3, a capacitor C4 charged from a DC power supply E through a resistor R1 and a Zener diode ZD connected in parallel to the capacitor C4 serve as a power source of a voltage VCC. The reference voltage (2) obtained by dividing the voltage VCC by the resistors R6 and R7 is the comparator CP.

The voltage VCI of the capacitor C3 applied to the negative input terminal of the capacitor C3 and charged via the resistor R5 by the voltage VCC
is applied to the positive input terminal of comparator CP.

When a voltage having a forward polarity with respect to the diode D2 appears in the current transformer CT, a base current is supplied to the switching element Q1 through the resistor Ro with that voltage, and the switching element Q1 is turned on. At the same time, the voltage of the current transformer CT is applied to the base of the transistor Q3, turning on the transistor Q3. As a result, transistor Q4 is turned off, the short circuit of capacitor C3 is released, charging of capacitor C3 begins, and voltage VCS increases. After that, after a predetermined period of time has elapsed, the voltage V14 is the base! #
When voltage v8 is exceeded, the output of comparator CP1 is inverted, changing transistor Q2 from off to on, thereby cutting off the base current to switching element Q1 and turning off switching element Q1. As a result, a resonant current flows through the resonant circuit. The subsequent reversal of the direction of the resonant current turns off transistor Q3, thus turning on transistor Q4, shorting capacitor C3, restoring the output of comparator CP1 and turning off transistor Q2. After this, when the direction of the resonant current returns to the original direction and becomes forward polarity with respect to the diode D2, the switching element Q1 is turned on again and the above operation is repeated, and the oscillation operation continues with the above operation. become.

SW is a power switch.

Next, switching circuit 4. The temperature detection circuit 5 and the dimmer switch circuit 6 will be explained in detail.

The switching circuit 4 corresponds to the switching circuit (2) in FIG.
The collector is connected to the ground line. In addition, a capacitor C5 is connected between the base and collector of the transistor Q5.
is connected. Furthermore, the collector and emitter of the transistor Q6 are connected in parallel between the emitter and collector of the transistor Q.

The temperature detection circuit 5 corresponds to the temperature detection circuit ■ in FIG.
A series circuit of a resistor RI3 and a thermistor TH is connected to both ends of the capacitor C4 of the timer circuit 3, and the connection point thereof is connected to the base of the transistor Q5 via a resistor R1. The thermistor TH has negative characteristics, and its resistance value decreases as the temperature rises.

The dimmer switch circuit 6 corresponds to the dimmer switch (2) in FIG. 1, and has a resistor RI4. Connect the series circuit of RI5 in parallel, and connect the dimmer switch S in parallel with the resistor R15.
W2 and resistance RI6. A series circuit with R17 is connected, and the connection point between resistors R18 and R17 is connected to the base of transistor Q6.

The operation of these circuits will be explained below.

By arbitrarily setting the reference voltage of timer circuit 3,
The on-duty of transistor Q1 can be changed, and therefore the oscillation frequency can be changed.

Voltage ■. , a constant DC voltage is applied, and the transistor Q5 is controlled to be turned on or off by the divided voltage of the resistor R13 and thermistor TH.

Now, when the ambient temperature exceeds a certain temperature, the thermistor T
The resistance value of H1 becomes smaller, the transistor Q5 turns on, and the reference voltage (2) becomes smaller due to the voltage division between the parallel circuit of the resistor R7°R1) and the resistor R6, and the on-duty of the transistor Q1 becomes smaller, thus causing oscillation. The frequency increases and the lamp current decreases, resulting in a dimmed lighting state.

By doing this, when the ambient temperature is high for a discharge lamp l placed in a sealed device for outdoor use, the lamp current is reduced to suppress the increase in the tube wall temperature of the discharge lamp l and maintain the light output. At the same time, heat generation of the circuit elements constituting the inverter circuit 1 and the like is suppressed.

Also, if the ambient temperature is below a certain temperature, the thermistor TH
, becomes large, transistor Q5 is turned off, and the rated light is turned on. At this time, if the dimmer switch SW2 is turned on, the resistor R1+ is connected in parallel with the resistor R7,
Similar to the above operation, the discharge lamp 1 enters a dimmed lighting state.

FIG. 4 is a diagram showing the operation of the discharge lamp lighting device shown in FIG.
(a) shows the change in the resistance value of the thermistor TH with respect to a change in the ambient temperature T, and ('b) shows the on/off state of the transistor Q.

In Fig. 4 fa), when the ambient temperature TI is lower than the predetermined value Tll, I, the resistance value of the thermistor TH is greater than R1, and when the ambient temperature T is higher than the predetermined value T□, the resistance value of the thermistor TH, is greater than R1. R1). In addition, in Fig. 4 (bl), the resistance value of the thermistor TH is R
1) indicates that the transistor Q5 changes from off to on, and when the transistor Q5 is off, rated lighting and dimmed lighting can be arbitrarily selected. Further, when the transistor Q5 is on, only dimmed lighting is performed.

The discharge lamp lighting device of this embodiment can forcibly enter the dimming lighting mode regardless of the state of the dimming switch circuit 6 when the ambient temperature T of the discharge lamp l becomes equal to or higher than a predetermined value Ta1). When the ambient temperature T□ is high, it is possible to suppress the rise in temperature of the coldest point of the discharge lamp l during rated lighting, thereby reducing the light output of the discharge lamp l and shortening the lifespan and destruction of the circuit elements that make up the lighting circuit. etc. can be prevented.

A second embodiment of the discharge lamp lighting device according to the invention set forth in claim (1) will be described with reference to FIGS. 5 and 6. In this discharge lamp lighting device, as shown in Fig. 5, a two-stone push-pull type inverter circuit is used as the inverter circuit 12 for converting the commercial IT source 1) into high frequency, and the secondary winding of the oscillation transformer TR is A series circuit of a discharge lamp 17 such as a fluorescent lamp and a current-limiting choke coil 15 is connected to both ends. At both ends of the current limiting choke coil 15,
The normally closed contacts of relay RY are connected.

In the temperature detection circuit 13, a parallel circuit of a capacitor C21 and a Zener diode ZD2 is connected via a resistor RH for controlling the power source, and a resistor R8,
A series circuit consisting of a positive temperature coefficient thermistor PTC and a positive temperature coefficient thermistor PTC is connected.

In the switching circuit 14, the connection point between the resistor R22 and the positive temperature coefficient thermistor PTC is connected to the transformer QH through the resistor R23.
connected to the base of The collector of the transistor Q□ is connected to the control power source via the coil of the relay RY. Between the collector and emitter of transistor Q21,
The collector and emitter of the transistor Q0 are connected in parallel, and the base of the transistor Q22 is connected to the dimmer switch circuit 1.
6.

Next, the operation will be explained.

Now, when the ambient temperature TC is low, the resistance value of the positive characteristic thermistor PTC becomes small, the base-emitter voltage VIE of the transistor Q□ becomes low, and the transistor Q
21 is in an off state. As a result, the coil of the relay RY is no longer energized, the contacts of the relay RY are turned on, both ends of the current limiting choke coil 15 are short-circuited and no longer function as an impedance, and the discharge lamp 17 is in its rated lighting state. If the transistor Q22 is turned on by the dimming signal from the dimming switch circuit 16 in this state, the coil of the relay RY is turned on, the contact of the relay RY is turned off, and the current limiting choke coil 15
acts as an impedance, and the discharge lamp 17 enters a dimming lighting state.

Next, when the ambient temperature Tc rises, the transistor Q2+ is turned on by the opposite operation to the above, energizing the coil of the relay RY, and the contact of the relay RY is turned off. As a result, the current limiting choke coil 15 acts as an impedance, and the discharge lamp 17 enters a dimming lighting state.

As described above, when the ambient temperature Tc is high, the lamp current is reduced compared to when the ambient temperature Tc is low, and the discharge lamp 17 is brought into the dimming lighting state. In this case, the discharge lamp 17 is in a dimmed lighting state regardless of the output signal of the dimming switch circuit 16. Conversely, the ambient temperature T.

When the lamp is low, the lamp current is increased to maintain the rated lighting state to prevent a decrease in light output. At this time, if there is a dimming signal from the dimmer switch circuit 16, the discharge lamp 17
is in a dimmed lighting state.

FIG. 6 is a diagram showing the operation of the discharge lamp lighting device shown in FIG.
al is a positive characteristic thermistor P with respect to changes in ambient temperature T.
It shows the resistance value change of TC. 1bl shows the on/off state of the transistor 'h+, and when the ambient temperature Tc exceeds a predetermined value Tc, I, the transistor QH changes from off to on. In the same figure (el indicates the on/off state of the contact of relay RY, which responds to transistors Q and 1.

This embodiment has the same effects as the embodiment shown in FIG.

In the above embodiment, the inverter circuit 12 includes two
Although a push-pull type inverter circuit is used, a half-bridge type inverter circuit or an inverter circuit with other configurations may also be used.

Claim +1). A third embodiment of the discharge lamp lighting device corresponding to the combination of the inventions described in f21 will be described based on FIGS. 7 and 8. This discharge lamp lighting device is a seventh
As shown in the figure, the temperature detection/switching circuit 7 is the one in Figure 3.
is added, and the rest is the same as that in Fig. 3.

The temperature detection/switching circuit 7 connects the emitter and collector of a transistor Q7 between the timer circuit 3 and the switching circuit 4, and inserts and connects a capacitor C6 between the base of the transistor Q7 and the ground line. C
A series circuit of a resistor R19 and the thermistor TH2 is connected in parallel between both ends of the resistor R1) and the thermistor TH2, and a resistor R1) is inserted and connected between the connection point of the resistor R1) and the thermistor TH2 and the voltage VCC.

Next, the operation of this circuit will be explained.

Thermistor TH2 detects the ambient temperature T1 and sets a predetermined value T,
If it is higher than L, the resistance value of the thermistor TH2 becomes small, turning on the transistor Q7, and in the case of this predetermined device or above, it becomes possible to operate the dimming resistor R1+ to perform dimming.

On the other hand, when the ambient temperature T, becomes lower than the predetermined values T, L, the resistance value of the thermistor TH2 increases, and the transistor Q
7 is turned off, and the dimming lighting mode cannot be selected.

Note that the ambient temperature TI is a predetermined value T. If the value exceeds 1, the rated lighting mode cannot be selected due to the operation of the temperature detection circuit 5 and the switching circuit 4 in a manner similar to that shown in FIG.

Therefore, in the discharge lamp lighting device of FIG. 7, only when the ambient temperature T is in the range of T, L≦T,≦T,
Both rated lighting mode and dimming lighting mode can be selected. In the range of T, <T, L, the dimming lighting mode cannot be selected and the discharge lamp 2 can be lit only in the rated lighting mode. In the range of Ta>T□, the rated lighting mode cannot be selected and the discharge lamp 1 can be lit only in the dimming lighting mode.

FIG. 8 is a diagram showing the operation of the discharge lamp lighting device of FIG.
al indicates a change in the resistance value of the thermistor TH2 with respect to a change in the ambient temperature T8, (bl indicates an on/off state of the transistor Q7, and (C1 indicates an on/off state of the transistor Q5).

In FIG. 8 [al, when the ambient temperature T is lower than the predetermined value 'I'st, the resistance value of the thermistor TH□ is greater than RCI (when the resistance Rc is higher than the predetermined value T@t) This shows that the resistance value of the thermistor TH2 becomes PCI. Also, Figure 8 (bl) shows that the transistor Q7 changes from off to on when the resistance value of thermistor TH2 becomes PCI. When the transistor Q7 is off, only the rated lighting is possible.Also, when the transistor Q7 is on, the rated lighting and dimmed lighting can be selected arbitrarily. This is as described in the first embodiment.

In this embodiment, it is possible to achieve the same effect as in the embodiment shown in FIG.
When the temperature drops below IL, the rated lighting mode can be forcibly set regardless of the state of the dimmer switch circuit 6, and it is possible to prevent the discharge lamp l from extinguishing during dimmer lighting when the ambient temperature TA is low. .

〔Effect of the invention〕

According to the discharge lamp lighting device recited in claim fil, when the ambient temperature of the discharge lamp exceeds a predetermined value, the dimming lighting mode can be forcibly entered regardless of the state of the dimmer switch, and the ambient temperature is high. Accordingly, it is possible to suppress an increase in the temperature of the coldest point of the discharge lamp during rated operation in the case of rated operation, thereby preventing a decrease in the light output of the discharge lamp and shortening the lifespan and destruction of circuit elements constituting the lighting circuit.

According to the discharge lamp lighting device according to claim (2), when the ambient temperature of the discharge lamp falls below a predetermined value, the rated lighting mode can be forcibly set regardless of the state of the dimmer switch, and the ambient temperature It is possible to prevent the discharge lamp from going out during dimming lighting when the intensity is low.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of the discharge lamp lighting device of the present invention, FIG. 2 is an explanatory diagram showing its operation, and FIG. 3 shows the discharge lamp lighting device of the first embodiment corresponding to claim il+. 4 is an explanatory diagram showing the operation of FIG. 3, FIG. 5 is a circuit diagram showing the discharge lamp lighting device of the second embodiment corresponding to claim fl), and FIG. An explanatory diagram showing the operation of the figure, FIG. 7 is claim (1). FIG. 8 is a circuit diagram showing the discharge lamp lighting device of the third embodiment corresponding to the combination (2), and FIG. 8 is an explanatory diagram showing the operation of FIG. 7. ■...Lighting circuit, ■...Switching circuit, m...Dimmer switch, ■...Temperature detection circuit,!・・・Discharge lamp hi Psuf Ren t Go figure figure figure figure figure illustration TA ('C) (C) RY le 1-te: E1! Hill - Figure j 4

Claims (2)

[Claims] (1) In a discharge lamp lighting device configured such that the lighting mode of a lighting circuit for lighting a discharge lamp can be switched between a rated lighting mode and a dimming lighting mode by a switching circuit in response to the operation of a dimmer switch, A temperature detection circuit for detecting ambient temperature is provided, and based on the output of the temperature detection circuit, when the ambient temperature of the discharge lamp exceeds a predetermined value, the lighting mode of the discharge lamp is set regardless of the state of the dimmer switch. A discharge lamp lighting device characterized in that the switching circuit is configured to forcibly switch to a dimming lighting mode. (2) In a discharge lamp lighting device configured such that the lighting mode of a lighting circuit for lighting a discharge lamp can be switched between a rated lighting mode and a dimming lighting mode by a switching circuit in response to operation of a dimmer switch, A temperature detection circuit for detecting ambient temperature is provided, and based on the output of the temperature detection circuit, when the ambient temperature of the discharge lamp becomes below a predetermined value, the lighting mode of the discharge lamp is set regardless of the state of the dimmer switch. A discharge lamp lighting device characterized in that the switching circuit is configured to forcibly switch to a rated lighting mode.