JPH02256198A - Fluorescent lamp lighting device - Google Patents

Abstract

PURPOSE:To surely perform dim-lighting at a low temperature by fully lighting a fluorescent lamp with a full lighting starting circuit then changing it to dim lighting when a power switch turned on while a dimming switch is set to the dim lighting state. CONSTITUTION:A fluorescent lamp 1 is fully lighted by the rated lamp current. When the charging voltage of a capacitor 14 reaches the operating voltage of a Zener diode 16, the Zener diode 16 is operated, and the first transistor 9 is turned on. The second oscillating resistor R2 is connected in parallel with the first oscillating resistor R1, the oscillation frequency of a timer IC 10 is highly modulated, and the fluorescent lamp 1 is changed from full lighting to dim lighting to maintain lighting. When the fluorescent lamp 1 is dim-lighted by the on-operation of a power switch 4, it is first fully lighted for a short period then changed to dim lighting, thus dim lighting can be surely performed at a low temperature.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is a separately excited type fluorescent lamp lighting device that lights a fluorescent lamp using a high-frequency inverter. This invention relates to a fluorescent lamp lighting device with a step-by-step dimming function.

[Conventional technology]

Fluorescent lamp lighting devices using a high-frequency inverter lighting method, which modulates the commercial frequency to a high frequency of several tens of kHz to light the fluorescent lamp at high frequency, are equipped with separately excited oscillation circuits and those equipped with self-excited oscillation circuits. It is prized for its ability to perform multi-stage dimming and continuous dimming easily and at low cost using frequency modulation. This pre-excitation type fluorescent lamp lighting device is equipped with a manual power switch such as a wall switch and a manual dimmer switch such as a pull switch, and turns off the fluorescent lamp by turning on the power switch and switching the dimmer switch. A specific example of a device having a dimming function that switches between a plurality of lighting states, including a plurality of lighting states, is shown in FIG. 2, and will be described.

The second fluorescent lamp lighting device lights up the fluorescent lamp (1) at full brightness at 100% of the rated brightness, and then lights up the fluorescent lamp (1) at full brightness.
1) is turned on at a lower brightness than when the full light is on, then the fluorescent lamp (1) is turned off, the security bulb (2) is turned on, and finally the security bulb (2) is turned off. In the figure, (3) is a commercial tributary power supply, (4) is a power switch such as a wall switch, and (5) is a dimmer switch with a 4-stage pull switch, which can be operated by a pull cord to illuminate the fluorescent light. All-light contact a that lights up the lamp (1), fluorescent lamp (1)
The dimmer contact b, which turns on the light after reducing the brightness, the safety ball contact C, which lights the safety bulb (2), and the all-off contact d, which turns off the safety bulb (2), are sequentially moved.

(6) is a noise filter circuit, (7) is a DC power supply circuit, and when the power switch (4) is in the on state and the dimmer switch (5) is in the all-light contact a or dimmer contact position, The tributary voltage of the commercial AC power supply (3) is stepped down, full-wave rectified, and smoothed by a smoothing capacitor C1 to a constant voltage of, for example, 12V.

(8) is a separately excited oscillation circuit that oscillates when the constant voltage of the DC power supply circuit (7) is applied and lights up the fluorescent lamp (1) at high frequency. A switching element that switches in two stages is, for example, a first transistor.

The oscillation circuit (8) includes, for example, a starting capacitor C2 that is charged with the DC voltage of the DC power supply circuit (7), and a timer IC that instantaneously oscillates when the charging voltage of the starting capacitor C2 is applied.
(10) and a MOS-FET oscillation transistor (
11), the oscillation transformer T1 oscillates due to the switching operation of the oscillation transistor (11), and the fluorescent lamp (1)
lights up. Primary winding N of current limiting means of fluorescent lamp (1)
The voltage induced in the secondary winding N2 of the current transformer T2 having a voltage of 1 is fed back to the timer IC, and the timer IC (10) maintains oscillation. Timer IC (1
0) is equipped with, for example, two first and second oscillation resistors R1 and R2 and one oscillation capacitor C2 as impedance elements that determine the oscillation frequency, and the first oscillation resistor R1 and the second oscillation resistor R2 are connected to the first transistor (9). ) are connected in parallel. When the first transistor (9) is off, the timer IC10) is connected to the first oscillation resistor R1 and the oscillation capacitor C2.
When the fluorescent lamp (1) is fully lit and the first transistor (9) is turned on, the second oscillating resistor R2 is connected in parallel to the first oscillating resistor R1, and the timer is activated. The oscillation frequency of the IC (10) becomes one step higher, the lamp current decreases by that much, and the fluorescent lamp (1) is switched to dimming mode. The on/off control of the first transistor (9) is performed by the dimmer switch (5).
The second transistor Tr is connected to the all-optical contact point a of ) via the diode D1 and resistor R3, as follows.

The dimmer switch (5) moves to all-light contact a and all-light contact a
When a commercial AC voltage is applied to the second transistor Tr
is turned on and the first transistor (9) is turned off. When the dimmer switch (5) is switched from the all-light contact a to the dimmer contact, the first transistor Tr is turned off, and the first transistor (9) is turned on with the DC voltage that operates the timer IC (10). do.

The lighting circuit performs the following operation. With the power switch (4) turned on, switch the dimmer switch (5) to all-light contact a. Then, the commercial AC voltage becomes the DC power supply circuit (7)
The starting capacitor C2 is charged with the rectified DC voltage, and during this charging, the timer IC (10) instantaneously oscillates to instantaneously switch the oscillation transistor (II), causing the oscillation transformer T1 to instantaneously oscillate. Fluorescent lamp (1
) lights up. At this time, the second transistor Tr is on and the first transistor (9) is off, so
The timer rc (10) oscillates at a frequency determined by the first oscillation resistor R1, and the fluorescent lamp (1) is fully lit. When this fluorescent lamp (1) is lit, a current flows through the primary winding N1 of the current transformer T2, and a voltage is induced in the second winding N2, and this voltage is passed through the diode D2 and resistor R4 to the timer IC (10). is fed back to the timer IC (
10) continues to oscillate, and the fluorescent lamp (1) remains fully lit even after charging of the starting capacitor C2 is completed.

When the dimmer switch (5) is switched to the dimmer contact, the second transistor Tr is turned off and the first transistor (9) is turned on instead, causing the first oscillation resistor R1 of the timer IC (10) to Two oscillation resistors R2 are connected in parallel, the oscillation frequency of the timer rc (10) is highly modulated, and the fluorescent lamp (1) is switched from full-light lighting to dimming lighting.

Next, when you switch the dimmer switch (5) to the safety ball contact C,
The DC power supply circuit (7) is cut off from the commercial AC power supply (3), the oscillation circuit (8) stops oscillating, the fluorescent lamp (1) goes out, and the safety bulb (2) lights up instead. At this time,
The starting capacitor C2 is discharged via the resistor R5 to prepare for starting the next time the fluorescent lamp is turned on. Next, the dimmer switch (5
) is switched to the all-off contact d, the safety bulb (2) turns off.

[Problem to be solved by the invention]

The power switch (4) in the above lighting device is located away from the lighting equipment so that the lighting equipment can be turned on and off by turning the power switch on and off, but the dimmer switch (5) When the fluorescent lamp (1) is turned on by turning on the power switch (4) when the fluorescent lamp (1) is in the dimming contact position, the following problem occurs. In other words, when dimming the light, turn off the power switch (4) to turn off the light, and then turn on the power switch (4), the starting capacitor C
2, the timer IC (10) instantaneously oscillates and starts the fluorescent lamp (1), but at this time the dimmer switch (5) is in the position of the dimmer contact and the first transistor (9) is turned on and the first and first oscillation resistors RIR2 are connected in parallel, so the oscillation frequency of the timer IC (10) is high, so the lamp current is small and the fluorescent lamp (1) is lit. (The fluorescent lamp (1) was difficult to turn on, especially at low temperatures, and in worse cases it would not turn on. For this reason, lighting equipment equipped with a power switch (4) and a dimmer switch (5) Although the lighting operation is convenient, there remains the problem of lack of reliability due to the above-mentioned uncertainty in dimmed lighting.

Therefore, an object of the present invention is to provide a highly reliable method that reliably dims and lights up a fluorescent lamp even when the power switch is turned on when the dimmer switch is in a state where the fluorescent lamp is dimmed and lit. An object of the present invention is to provide a fluorescent lamp lighting device of the same size.

[Means to solve the problem]

In order to achieve the above object, the present invention includes a DC power supply circuit that steps down and rectifies a commercial AC voltage applied through a power switch and an open switch, and oscillates by applying the DC voltage of the DC power supply circuit, and the oscillation frequency is It is equipped with a separately excited oscillation circuit that lights a fluorescent lamp at a high frequency at a brightness determined by In the lighting circuit, the dimmer switch is in a state where the fluorescent lamp is dimmed and lit with a lamp current lower than the rated lamp current, and the oscillation circuit is in a state where the fluorescent lamp is dimmed and lit with a lamp current lower than the rated lamp current, and the oscillation circuit dims the fluorescent lamp at the rated lamp current for a certain period of time from the time the power switch is turned on. The lamp is characterized in that it is equipped with a full-light lighting start circuit that controls on/off the switching element so that the lamp oscillates at an oscillation frequency that causes full-light lighting with the lamp □ current.

In addition, the full-light lighting start circuit includes a CR time constant circuit having a capacitor that is charged via a resistor with the DC voltage of the DC power supply circuit, and a switching element until the charging voltage of the capacitor of the CR time constant circuit reaches a predetermined value. For practical purposes, it is desirable to have a Zener diode that maintains the fluorescent lamp in an operating state in which the fluorescent lamp is fully lit.

[Effect]

If you turn on the power switch while the dimmer switch is in the dimmer lighting state, the full-light lighting start circuit maintains the oscillation frequency of the oscillation circuit at the value when the full light is on for a certain period of time from the time the switch is turned on. , the fluorescent lamp is turned on at full power for a predetermined period of time and then switched to dimmed lighting to ensure lamp startup.

〔Example〕

The embodiment will be explained as follows based on FIG. 1.

The first fluorescent lamp lighting device is a full-light lighting start circuit (12) which is a feature of the present invention in the fluorescent lamp lighting device shown in FIG.
The same or equivalent parts as in FIG. 1 and FIG. 2 are given the same reference numerals, and their explanation will be omitted. When the power switch (4) is turned on when the light release switch (5) is in the light release contact position, the full light lighting start circuit (12) performs switching for oscillation frequency modulation of the oscillation circuit (8) for a certain period of time. The first transistor (9), which is an element, is held in the off state to turn on the fluorescent lamp (1) at full brightness, and after a certain period of time, the first transistor (9) is turned on to dim the fluorescent lamp (1). It lights up.

To explain the full-light lighting start circuit (12) in detail with a concrete example, it is a CR time constant circuit having a capacitor (14) that is charged via a resistor (13) with a DC voltage that operates a timer IC (10). (15), and a Zener diode (16) which becomes conductive and turns on the first transistor (9) when the charging voltage of the capacitor (14) reaches a predetermined level. Resistor (13) and capacitor (1
A Zener diode (10) is connected between the midpoint of the capacitor (1) and the base of the first transistor (9).
4), the collector and emitter of the second transistor Tr are connected in parallel.

Therefore, the lighting device of the above embodiment performs the following operation. Turn on the power switch (4) and turn on the dimmer switch (5).
) is switched to the all-light contact a, the second transistor Tr is turned on, the first transistor (9) is turned off regardless of the all-light lighting start circuit (12), and the timer IC (10) is turned on. The fluorescent lamp (1) is fully lit by oscillating at a low frequency determined by the first oscillation resistor R1. Next, when the dimmer switch (5) is switched to the dimmer contact, the second transistor Tr is turned off, and the capacitor (1
4) is in a fully charged state and the Zener diode (16)
is in a conductive state, the first transistor (9) turns on and the oscillation frequency of the timer IC (10) increases,
The fluorescent lamp (1) is dimmed and turned on. This dimming lighting is performed reliably because it is a transition from full-bright lighting. Next, when the dimmer switch (5) is switched to the safety bulb contact C, the safety bulb (2) lights up, the oscillation circuit (8) stops oscillating, and the fluorescent lamp (
1) goes out, and the capacitor (14) discharges through the resistor (13). When the dimmer switch (5) is switched to the all-off contact d, the safety bulb (2) is turned off. Dimmer switch (5
) is in any lighting state, when the power switch (4) is turned off, all lights are turned off.

Here, when the dimmer switch (5) is in the dimmer contact position and the fluorescent lamp (1) is dimmed, turn off the power switch (4) to turn off the light, then turn the power on. Consider the case where the switch (4) is turned on to dimly light the fluorescent lamp (1). When the power switch (4) is turned from OFF to ON, charging of the capacitor (14) of the full-light lighting start circuit (12) starts, and the charging continues until the charging voltage reaches the operating voltage of the Zener diode (16). 1 transistor (9) maintains the off state, and the timer rc (
10) starts oscillating at a low frequency determined by the first oscillation resistor R1, and therefore, the fluorescent lamp (1) is fully lit at the rated lamp current. When the charging voltage of the capacitor (14) reaches the operating voltage of the Zener diode (16), the Zener diode (16) operates and the first transistor (9) is turned on, causing the first oscillation resistor R1 to generate a second oscillation. Resistance R2
are connected in parallel, the oscillation frequency of the timer IC (10) is highly modulated, and the fluorescent lamp (1) shifts from full-light lighting to dimmed lighting and remains lit. The temporary total lighting time of this fluorescent lamp (1) at startup is determined by the CR time constant circuit (15
), and this time is suitably about 0.5 seconds to 1 second. In this way, when turning on the fluorescent lamp (1) in a dimmed manner by turning on the power switch (4), it is possible to turn on the fluorescent lamp (1) in a dimmed manner even at low temperatures by first allowing it to be fully illuminated for a short period of time and then switching to dimmed lighting. It will definitely be done.

It should be noted that the present invention is not limited to the above-mentioned embodiments, but can also be applied to a lighting device in which a fluorescent lamp is opened in multiple stages, including full-light lighting and multiple dimmer lighting. The oscillation frequency may be modulated by switching the connection state of a plurality of oscillation capacitors using a switching element.

〔Effect of the invention〕

As described above, according to the present invention, when the dimmer switch is in the dimmer lighting state and the power switch is turned on, the fluorescent lamp is fully lit by the full-light lighting start circuit, and then the dimmer is turned on. As a result, lighting is performed reliably, and the reliability of dimmed lighting is increased especially at low temperatures, making it possible to realize a highly reliable lighting device.

In addition, the full-light lighting start circuit is made up of resistors and capacitors.
By configuring the circuit with a time constant circuit and a Zener diode, a simple and inexpensive full-light lighting start circuit can be realized, and the addition of the full-light lighting start circuit to a lighting device can be advantageous in terms of circuit configuration and cost.

[Brief explanation of drawings]

FIG. 1 is a lighting circuit diagram showing an embodiment of the present invention. FIG. 2 is a lighting circuit diagram of a fluorescent lamp lighting device which is a premise of the present invention. (1) - 111 fluorescent lamp, (4) - power switch, - dimmer switch, - oscillator circuit, - full lighting star - resistor, - CR time constant circuit, (7”) - DC power supply circuit, (9) - Switching element circuit, (14) ---- Capacitor, (16) - Zener diode - Applicant NEC Home

Claims (2)

[Claims] (1) A DC power supply circuit that steps down and rectifies the commercial AC voltage applied through the power switch and dimmer switch, and oscillates when the DC voltage is applied to the DC power supply circuit, and fluoresces with a brightness determined by the oscillation frequency. A separately excited oscillation circuit that lights the lamp at high frequency, a switching element that modulates the oscillation frequency of the oscillation circuit in multiple steps by controlling on/off by manual switching of the dimmer switch, and a dimmer switch that lights the fluorescent lamp. The oscillation circuit oscillates at an oscillation frequency that lights up the fluorescent lamp at the rated lamp current for a certain period of time from the moment the power switch is turned on, when the lamp is dimmed and lit with a lamp current lower than the rated lamp current. What is claimed is: 1. A fluorescent lamp lighting device comprising: a full-light lighting start circuit that controls on/off a switching element to (2) A CR time constant circuit that has a capacitor that is charged via a resistor with the DC voltage of the DC power supply circuit, and the fluorescent lamp lights up the switching element until the charging voltage of the capacitor in the CR time constant circuit reaches a predetermined value. 2. The fluorescent lamp lighting device according to claim 1, further comprising a full-light lighting start circuit including a Zener diode for maintaining the lighting operating state.