JPH05234693A - Electric discharge lamp lighting circuit - Google Patents

Abstract

PURPOSE:To prevent excess lighting and to reduce power consumption by changing the frequency of an excitation circuit in response to an increase in surrounding illuminance and reducing the quantity of light of electric discharge lamps. CONSTITUTION:A DC power supply is switched using semiconductor elements (TR1, TR2) driven by an excitation circuit (4A) to provide a high frequency AC power. A separately-excited inverter electric discharge lamp lighting circuit which uses the high frequency AC power supply to light electric discharge lamps (3, 3A) is organized so that the resistance value of a resistor element (Rx) which determines the oscillation frequency of the excitation circuit (4A) varies in a manner than the frequency is changed and the quantity of light of the electric discharge lamps (3, 3A) being lighted is reduced in response to an increase in surrounding illuminance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a separately excited inverter type lighting circuit for a discharge lamp used in various discharge lamps such as a fluorescent lamp and a mercury lamp.

[0002]

2. Description of the Related Art When lighting a discharge lamp (for example, a fluorescent lamp or a mercury lamp), many inverter type lighting circuits are used because of little flicker during use, being unaffected by different power supply frequencies depending on the region, and having good power efficiency. Used. The inverter circuit for this discharge lamp uses a semiconductor element to switch the DC power supply obtained by rectifying and smoothing the AC power supply to preheat /
A high-frequency AC power supply for lighting is obtained, but a self-exciting method that uses a semiconductor switching element as part of an oscillation circuit, and a method that drives the switching element with the oscillation output of an excitation circuit independent of the semiconductor switching element Some are encouraged. Of these, a separately excited inverter circuit for a fluorescent lamp (for a discharge lamp) has been already proposed by the present applicant in order to solve some of the problems of the self-excited oscillation method (Japanese Patent Application No. 2-134897). ).

FIG. 6 is a circuit diagram showing an example of a separately excited inverter type discharge lamp lighting circuit 10 similar to this. In the figure,
Reference numeral 2 is a rectifying / smoothing circuit which is connected to the input AC power supply AC and rectifies the AC power to obtain the DC power supply DC. TR1 and TR2 are two Fs whose channels are connected in series to this DC power supply DC.
It is an ET transistor. Similarly, two capacitors C2 and C3 connected in series are connected to the DC power supply DC. An intermediate connection point P1 between the two FET transistors TR1 and TR2 and an intermediate connection point P2 between the two capacitors C2 and C3 are connected via a winding L4 of the output transformer T2. The transformer T2 is also provided with a winding L5 connected to both end electrodes of discharge lamps (fluorescent tubes) 3 and 3'connected in series. The outputs of the windings (L51, L52) at both ends of the winding L5 (that is, the ends of the winding L5 and the intermediate tap) are preheated to the filaments 3A, 3'B at the ends of the fluorescent tubes 3, 3 ', respectively. Is connected for. Further, the output of the winding (L53) different from the winding L5 is the filament 3B at the other end which is the connection point of the fluorescent tubes 3 and 3 '.
And 3'A are connected in parallel for preheating. A capacitor C4 is connected between the filaments at both ends of the two fluorescent tubes 3 and 3'connected in series.

Further, the FET transistors TR1 and T
The gate terminal of R2 is connected to the two outputs of opposite phase of the excitation circuit 4B. The excitation circuit 4B includes an IC circuit IC1, external resistors R1 and C1 for determining the oscillation frequency of the IC1, a winding L1 to which an output from the IC1 is connected, and two windings L2 and L3. Of the transformer T1. The outputs from the other two windings L2 and L3 of the transformer T1 are the two outputs of the above-mentioned excitation circuit 4 which are out of phase with each other and are the FET transistors TR1 and T
It is connected to the gate terminal of R2. Electric power is supplied to the excitation circuit 4 from a low voltage power source 5 which is connected to the output of the smoothing circuit 2 and produces a low voltage.

[0005]

By the way, in the conventional separately-excited inverter type discharge lamp lighting circuit including the above-mentioned examples, the output circuit is manufactured at the time of manufacture in order to supply sufficient electric power to the discharge lamp at the excitation frequency. It was fixedly set to a value close to the resonance frequency of and could not be changed after that. Therefore,
As a result, the discharge lamp is always turned on with a constant illuminance regardless of the user's intention, and there is an inconvenience that the user cannot use the discharge lamp in an optimum state. Further, there is also a disadvantage that power is unnecessarily consumed because the operation is continued at a constant illuminance even in a time period when strong illumination is not required depending on the changing brightness of the outside world. In particular, in a streetlight or the like installed outdoors, it is difficult to perform detailed power management, and the number of installations is enormous, so that the amount of wasted power is considerable.

The present invention has been made in view of such circumstances, and a lighting circuit for a discharge lamp capable of arbitrarily and easily adjusting illuminance (at the same time, electric power) according to a user's intention during lighting. The primary purpose is to provide. Further, the other inventions of the present application are only based on the addition of an extremely simple configuration, and automatically detect the case where the illumination illuminance is not so much required in consideration of the illuminance of the external environment, and automatically determine the illumination illuminance according to the illuminance of the external environment. It is a second object of the present invention to provide a discharge lamp lighting circuit that contributes to energy saving by reducing power consumption by adjusting (dimming).

[0007]

In the first invention of the present application, a direct current power source is switched using a semiconductor element driven by an excitation circuit to obtain a high frequency alternating current power source, and a discharge lamp is lit by this high frequency alternating current power source. In the excitation-type inverter type discharge lamp lighting circuit, the excitation circuit has a resistance element that determines the oscillation frequency based on the resistance value, and the resistance value of the resistance element can be arbitrarily changed for dimming during lighting. And

To achieve the second object, in the second invention of the present application, a direct current power source is switched by using a semiconductor element driven by an excitation circuit to obtain a high frequency alternating current power source, and a discharge lamp is lit by the high frequency alternating current power source. The separately-excited inverter-type discharge lamp lighting circuit, wherein the excitation circuit has a resistance element that determines the oscillation frequency by the resistance value, and the resistance value of the resistance element changes the frequency in accordance with an increase in ambient illuminance. It is configured to change so as to reduce the light amount of the discharge lamp during lighting.
In the third invention of the present application, the resistance element of the discharge lamp lighting circuit is a CdS element.

[0009]

In the above first invention of the present application, while the discharge lamp is being lit by the user, the resistance value of the resistance element of the excitation circuit is arbitrarily changed to change the oscillation frequency of the excitation circuit, so that the discharge lamp is supplied. The generated electric power is increased or decreased, and accordingly the discharge lamp can be dimmed to a desired illuminance. Further, in the above-mentioned second invention of the present application, if the resistance value of the resistance element of the excitation circuit is increased by the ambient illuminance, the resistance value is automatically changed in response to this, thereby changing the oscillation frequency of the excitation circuit, As a result, the power supplied to the discharge lamp increases and decreases, and accordingly, the discharge lamp is always lit with appropriate illuminance (and therefore with appropriate power), and excessive power is not consumed, and power can be saved. Note that the above-mentioned two inventions do not prevent simultaneous implementation, and can coexist to exhibit their respective operational effects.

[0010]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings based on embodiments. FIG. 1 is a circuit diagram of a lighting circuit 1 for a fluorescent lamp fixture according to an embodiment of the present invention. The schematic configuration of this embodiment circuit is substantially the same as that of the conventional separately excited inverter type fluorescent lamp lighting circuit 10 shown in FIG.
Only the portion associated with the excitation circuit 4 (resistor portion that determines the oscillation frequency) configured by C1 (IC circuit) is different.
The circuit of the embodiment will be described below, including a brief description of each part.

In FIG. 1, 2 is a rectifying / smoothing circuit for obtaining a DC power supply DC from an input AC power supply AC, and TR1 and TR2 are two FEs whose channels are connected in series to the DC power supply DC.
T-transistors C2 and C3 are two capacitors which are also connected in series to the DC power supply DC. The two FEs
Connection points P1 and 2 between T transistors TR1 and TR2
An intermediate connection point P2 between the capacitors C2 and C3 is connected via a winding L4 of the output transformer T2. The transformer T2 is also provided with a winding L5 connected to both electrodes of the fluorescent tubes 3 and 3'connected in series. The outputs of the windings (L51, L52) at both ends of the winding L5 (that is, the ends of the winding L5 and the intermediate tap) are connected to the filaments 3A, 3'B at both ends of the fluorescent tubes 3, 3 ', respectively. ing. The output of a winding (L53) different from the winding L5 is connected in parallel to the filaments 3B and 3'A at the other end which is the connection point of the fluorescent tubes 3 and 3 '. A capacitor C4 is connected between the filaments at both ends of the two fluorescent tubes 3 and 3'connected in series. In addition, the FE
The gate terminals of the T-transistors TR1 and TR2 are respectively connected to the two outputs of the excitation circuit 4 in opposite phases.

The excitation circuit 4 includes an IC circuit IC1 and this IC
External adjustment resistor Rx for determining the oscillation frequency of 1
(Resistive element) and C1, and a transformer T1 having a winding L1 to which the output from the IC1 is connected and two windings L2 and L3. Two outputs having opposite phases from the other two windings L2 and L3 of the transformer T1 are connected to the gate terminals of the FET transistors TR1 and TR2. Electric power is supplied to the excitation circuit 4 from a low voltage power source 5 connected to the output of the smoothing circuit 2. By the way, in the inverter type discharge lamp lighting circuit, as shown in the graph of FIG. 3, the power (input power, W) supplied to the discharge lamp is increased or decreased depending on the oscillation (excitation) frequency (f), which corresponds to this. The illuminance (Lx) can be changed. The oscillation frequency of the discharge lamp lighting circuit 1 (oscillation frequency of the excitation circuit 4)
Is an external component, that is, resistors R1 and C as described above.
Since it is determined by each value of 1, the resistance R can be easily set during use.
By adjusting the value of 1 or C1, the illuminance can be adjusted (the power can be adjusted at the same time).

In the discharge lamp lighting circuit according to the first invention of the present application, the adjusting resistance Rx (resistive element) of the above-mentioned two circuit elements is a variable resistance (volume), and the resistance value can be easily changed from the outside even when the user lights up. You can do it. For this purpose, a rotary variable resistor or a slide variable resistor is used as the adjustment resistor Rx. Then, by appropriately arranging the operation shaft or the operation lever for changing the resistance value so as to protrude outside the casing (not shown) of the discharge lamp lighting circuit, a knob or an operation piece is appropriately provided, and the user operates the resistance value. To be easily changed at any time. The oscillation frequency changes according to the resistance value set by the user, and the power supplied to the discharge lamp changes accordingly, and the illuminance increases or decreases to achieve the purpose of dimming. That is, in response to the user operating the operation lever to change the resistance value, the excitation frequency changes between the frequencies f ₁ and f ₃ shown in (C) of FIG. The illuminance changes within the range shown in FIG. At this time, the electric power supplied to the discharge lamp also changes within the range shown by (E).

Note that the resistance element is not a single variable resistor,
As shown only in the relevant part in FIG. 4, the external resistance element of the excitation circuit 4 is a series connection (or parallel connection) of the fixed resistance R ₇ and the variable resistance Rv, and the combined resistance value is changed by adjusting the variable resistance Rv. You can Thus, the AC power is supplied to the discharge lamps 3 and 3'through the transformer T2 at the oscillation frequency arbitrarily adjusted, and the discharge lamp is lit.

As described above, in the present invention, the target dimming function is added with only a very simple change. Since this dimming function directly adjusts the supplied power itself, it directly leads to the saving of power consumption, unlike the dimming means that consumes the power in other parts to obtain a predetermined light amount. In addition,
In order to change the oscillation frequency, either value of the resistors R1 and C1 may be changed, but the resistor is more suitable for easily changing the value.

Next, FIG. 2 is a circuit diagram showing an embodiment 1A of a discharge lamp lighting circuit according to the second invention of the present application. 2 is the same as the previous embodiment, except that the excitation circuit 4
In A, a resistance element Rx (dimming resistance) whose resistance value changes according to the surrounding illuminance is used instead of the adjustment resistance Rv.

The dimming resistance Rx is a resistance element whose resistance value decreases according to the amount of light in the outside world (external light), that is, according to the ambient illuminance, and which decreases as the ambient illuminance increases. For example, CdS.
A (cadmium sulfide) element is used and arranged so that light from the outside enters the light-receiving surface. The resistance value of the CdS element, which is a negative resistance photo-sensing element, decreases when it receives light energy. Therefore, the oscillation frequency of the excitation circuit, which is determined by the capacitor C1, is automatically f of FIG.
It moves to the higher frequency side shown by ₃ , and the illuminance decreases and the power consumption also decreases. Therefore, when it is used at home, it is possible to always obtain the illumination light of the optimum illuminance in consideration of the external illuminance such as sunshine, and when it is used for a street lamp, etc. It not only contributes to savings, but also extends the life of the streetlight itself.

Some streetlights have a function of automatically turning on and off according to the light and darkness of the outside world. However, this conventional lighting and extinguishing function is different from the dimming function in the present application, which conflicts again. However, they can be used complementarily. That is, the dimming function of the present application can further finely save power during the lighting period of the discharge lamp.

It is also possible to simultaneously apply the two types of dimming functions proposed by the present application (those according to the user's intention and those corresponding to external light) as described above to the discharge lamp lighting circuit. For example, as shown in FIG. 5 which shows only the main part (excitation circuit part), the adjustment resistor VR and the dimming resistor Rx which can be arbitrarily adjusted by the user are connected in series to the resistance element that determines the oscillation frequency of the oscillation circuit. However, both resistance value changes may be reflected in the oscillation frequency so that the illuminance can be adjusted arbitrarily, and the illuminance can be automatically increased or decreased in response to changes in external light.

Further, in the embodiment, the resistance element of the excitation circuit 4 (4A) is directly replaced by a variable resistance which can be changed or a resistance which is changed by external light. However, in addition to this, a semiconductor control element such as an FET is a resistance element. It is also possible to implement the present invention in combination with a photo-sensing element such as a phototransistor that controls the photo-transistor. The point is that the resistance element of the excitation circuit of the inverter circuit changes according to the operation of the user or the intensity of external light, and the oscillation frequency changes a predetermined amount, resulting in a change in the supplied power and the obtained illuminance. Is achieved.

[0021]

As described above, in the discharge lamp lighting circuit of the first invention of the present application, the excitation circuit of the separately excited inverter type discharge lamp lighting circuit has a resistance element that determines the oscillation frequency by the resistance value. Since the resistance value of the resistance element can be arbitrarily changed for dimming during lighting, the user can arbitrarily adjust the illuminance of the discharge lamp according to his / her preference. In addition, there is no waste of power because it is a system that adjusts the supplied power itself.

In the discharge lamp lighting circuit according to the second aspect of the present invention, the excitation circuit of the separately excited inverter type discharge lamp lighting circuit has a resistance element that determines the oscillation frequency based on the resistance value, and the resistance of the resistance element. Since the value changes so as to change the frequency according to the increase of the ambient illuminance and reduce the light amount of the discharge lamp during lighting, excessive lighting is automatically suppressed and unnecessary power consumption is suppressed. be able to. In addition, there is no waste of power because it is a system that adjusts the supplied power itself.

Further, in the third invention of the present application, the desired function is easily realized by using the CdS element as the resistance element of the discharge lamp lighting circuit.

[Brief description of drawings]

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

FIG. 2 is a circuit diagram showing an embodiment of a lighting circuit for a discharge lamp according to another invention of the present application.

FIG. 3 is a diagram showing an example of each relationship between an excitation frequency, power supplied to the discharge lamp, and illuminance of the discharge lamp, according to the discharge lamp lighting circuit of each invention of the present application.

FIG. 4 is a circuit diagram showing an embodiment of an excitation circuit according to the present invention.

FIG. 5 is a circuit diagram showing another embodiment of the excitation circuit according to the present invention.

FIG. 6 is a circuit diagram showing an example of a conventional discharge lamp lighting circuit.

[Explanation of symbols]

 1, 1A ... Discharge lamp lighting circuit, 3, 3 '... Discharge lamp, 4, 4A ... Excitation circuit, Rv, Rx ... Resistance element (variable resistance, dimming resistance), TR1, TR2 ... Semiconductor element.

Claims (3)

[Claims] 1. A high frequency alternating current power source is obtained by switching a direct current power source using semiconductor elements (TR1, TR2) driven by an excitation circuit (4), and a discharge lamp (3, 3 ') is generated by this high frequency alternating current power source. In the separately-excited inverter type discharge lamp lighting circuit for lighting, the excitation circuit (4) has a resistance element (Rv) that determines the oscillation frequency by a resistance value, and the resistance value of the resistance element (Rv) is being turned on. A lighting circuit for a discharge lamp, which can be arbitrarily changed for dimming. 2. A high frequency alternating current power source is obtained by switching a direct current power source using semiconductor elements (TR1, TR2) driven by an excitation circuit (4A), and a discharge lamp (3, 3 ') is generated by this high frequency alternating current power source. In the separately-excited inverter type discharge lamp lighting circuit for lighting, the excitation circuit (4A) has a resistance element (Rx) that determines the oscillation frequency by a resistance value, and the resistance value of the resistance element (Rx) is A discharge lamp lighting circuit characterized in that the frequency is changed according to an increase in ambient illuminance so as to reduce the light quantity of the discharge lamp (3, 3 ') during lighting. 3. The lighting circuit for a discharge lamp according to claim 2, wherein the resistance element (Rx) is a CdS element.