JP3022965U - Fluorescent light dimmer - Google Patents

Abstract

(57) [PROBLEMS] To provide a fluorescent light dimming device which eliminates flicker of a fluorescent lamp, can be initially lit at arbitrary brightness, and can perform stable dimming even at around 0%. An AC ballast is incorporated in a power input circuit 1. The double voltage and high voltage generation circuit 2 causes initial discharge. The filament is driven by the switching power supply circuit 3. The full-wave rectifier circuit 4 converts alternating current into direct current. Dimming is performed by the constant current control circuit 5. The polarity inversion circuit 6 switches the polarity at regular intervals. The starting circuit 6 determines the polarity at the time of initial discharge.

Description

[Detailed description of the device]

[0001]

[Technical field to which the device belongs]

 The present invention relates to a fluorescent lamp light control device capable of lighting a fluorescent lamp without flicker and performing initial lighting and dimming at any brightness from 0% to 100%.

[0002]

[Prior art]

 Several methods have conventionally been proposed for the dimming method of fluorescent lamps. For example, one of them is a dimming method in which a dedicated transformer is installed at a commercial frequency and the phase is controlled by a triac. In addition, there is an inverter system as a system that is widely used these days. A DC method has also been proposed, although it has not been widely used.

[0003]

[Problems to be solved by the device]

 However, the above-mentioned dimming method using phase control requires a dedicated fluorescent tube, which is expensive and heavy, and in addition, flickering is large and dimming around 0% is unstable. . Further, in the above-mentioned inverter system, the dimmable range is narrow, and it is necessary to perform initial lighting near 100%, and dimming around 0% is difficult. Furthermore, the conventional DC type has the problems that it is heavy, generates a lot of heat, has a narrow dimming range, and has a short life of the fluorescent tube. Not not.

In view of the above points, the present invention eliminates flicker, enables initial lighting at a desired brightness of 0% to 100%, and, moreover, enables stable dimming near 0%. It is intended to provide a dimmer.

[0005]

[Means for Solving the Problems]

 The technical means of the dimmer of the present invention is a power supply input circuit incorporating an AC ballast, a voltage doubler high voltage generation circuit connected to the power supply input circuit for the initial discharge of a fluorescent lamp, and a power supply A switching power supply circuit connected to the input circuit for both filament drive and control, a rectifier circuit connected to the power supply input circuit for converting AC to DC, and a constant current connected to this rectifier circuit. A control circuit, a polarity inversion circuit connected to this constant current control circuit for switching the polarity of the fluorescent tube at fixed time intervals, and a polarity inversion circuit connected to this polarity inversion circuit for initial discharge. It consists of a starting circuit.

Further, it is preferable to adopt a feedforward method for the switching power supply circuit, and the constant current control circuit is preferably composed of a drive circuit, a constant current circuit, and a volume control circuit. The polarity reversing circuit is preferably composed of an oscillation circuit and a polarity switching circuit.

[0007]

[Mode for Carrying Out the Invention]

 An embodiment of the dimmer of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of the light control device. Reference numeral 1 is a power supply input circuit, which connects an AC stabilizer to a commercial AC power supply (AC100V) to stabilize the power supply and suppress heat generation. A voltage doubler / voltage generator 2 generates a high voltage for initial discharge of the fluorescent lamp. 3 is a switching power supply circuit, which adopts a feedforward method. Reference numeral 4 is a full-wave rectification circuit that converts alternating current into direct current. Reference numeral 5 is a constant current control circuit, which dims by a constant current. Reference numeral 6 is a polarity reversing circuit, which switches the polarity by a semiconductor at regular intervals to prevent the electrodes of the fluorescent tube from being worn out. 7 is a starting circuit, which determines the polarity for initial discharge when the power is turned on.

Next, an example of each of the above circuits will be described. FIG. 2 shows an embodiment of the power input circuit 1. As the power supply input circuit, an LC type noise filter is generally adopted, but in this embodiment, an inexpensive RC type is used because it does not affect the circuit even if the voltage drops. An AC ballast (L1) is incorporated in this circuit. Since the AC ballast 1 has a large-capacity inductance, it absorbs a sudden current flowing in the circuit, and when the current increases, the impedance lowers the voltage, which helps the constant current control circuit 5 to bear the load and heat generated by the impedance. Since there is no heat generation, the overall heat generation is reduced, the power factor of the commercial power source is improved, the power efficiency is improved, and the noise backflow to the power source side is suppressed.

FIG. 3 shows an embodiment of the voltage doubler / voltage generator circuit 2. Since this circuit is only for initial discharge, the capacitor can be of low capacitance. When the discharge current flows, the impedance and the resistance of the capacitor reduce the voltage down to the discharge voltage of the fluorescent lamp. Also, if the discharge stops, no current will flow, so the voltage will suddenly rise and the battery will be discharged again. The resistors R2, R3, and R4 are connected in series with low-priced resistors to obtain a high resistance value and a breakdown voltage.

FIG. 4 shows an embodiment of the switching power supply circuit 3. Here, the feed-forward method with good transformer efficiency is used. Even if the output voltage fluctuates slightly, it does not affect the dimming, so the voltage is not fed back at a fixed frequency and a fixed pulse width, reducing the cost.

FIG. 5 shows an embodiment of the full-wave rectifier circuit 4. Here AC is converted to DC. A fluorescent tube up to 30 W can be driven by this rectifier circuit. However, since the lighting voltage becomes higher at 40 W or higher, it is preferable to use the voltage doubler rectifier circuit of FIG.

The constant current control circuit 5 includes the drive circuit shown in FIG. 7, the constant current circuit shown in FIG. 8, and the volume control circuit shown in FIG. The drive circuit of FIG. 7 controls the polarity and current of the fluorescent tube (FL). Further, the diodes D1 and D2 and the contact Y1 prevent the reverse flow of the starting high voltage. The diodes D1 and D2 are connected in series in order to increase the breakdown voltage, eliminate the leakage current, and allow the discharge current after starting to flow. R1 is a current detection resistor, which is fed back to the constant current circuit. Further, the resistors R5 and R6 allow a minute current to flow even near 0% to maintain the discharge and lower the voltage of the voltage doubler high voltage generation circuit 2 to increase the breakdown voltage of the semiconductors (power transistors) Q1 and Q3. Also, the minimum value of stable discharge is determined by this resistance value. Further, the resistor R7 absorbs an excessive change of the fluorescent tube (FL) to supplement the constant current capability, and also absorbs the voltage to suppress the heat generation of the semiconductors Q1 and Q3. Since the semiconductors Q1 and Q3 both perform polarity reversal and constant current control and generate heat by absorbing voltage, heat dissipation is necessary. Since the semiconductors Q2 and Q4 are switched and do not generate much heat, there is no need to radiate heat. A filament power supply is used to drive the semiconductor Q2, but a starting power supply is connected to Q4. In order to prevent high voltage backflow, each power supply is insulated. In the constant current circuit of FIG. 8, the control voltage input is converted into a current. In the volume control circuit of FIG. 9, dimming is performed by connecting to the constant current circuit. REG is a voltage stabilizing circuit.

The polarity reversing circuit 6 is composed of the oscillation circuit of FIG. 10 and the polarity switching circuit of FIG. In the oscillator circuit, the polarity switching time is kept constant. The polarity switching circuit uses an analog switch to drive the photocoupler on the high side and switch the constant current control voltage on the low side.

FIG. 12 shows an embodiment of the starting circuit 7. In this starting circuit 7, when the power is turned on, the polarity is set for the initial discharge and the contact Y1 is temporarily cut off.

It should be noted that the present invention is not limited to the above-described embodiment, and can be freely modified and implemented within the scope of the claims of the utility model.

[0016]

[Effect of device]

 In the fluorescent light control device of the present invention, the fluorescent lamp is discharged with direct current, and the filament power source is also direct current, so it can be turned on without flicker. Further, since the fluorescent lamp is initially discharged by the voltage doubler / high voltage generation circuit, the initial lighting can be performed with any brightness from 0% to 100%. Furthermore, since an AC ballast is incorporated in the power supply input circuit, when the current increases, the voltage automatically drops, reducing the load on the constant current circuit and suppressing heat generation. Further, since the dimming is performed by the constant current control circuit, the dimming can be stably performed even near 0%. Further, since the polarity is switched by the polarity reversing circuit at regular intervals, it is possible to prevent the electrode from being worn down and to extend the life of the fluorescent tube. Furthermore, since a switching power supply circuit is used instead of a commercial transformer, weight reduction is possible.

According to the second aspect of the present invention, since the feedforward system is adopted in the switching power supply circuit, the transformer efficiency is good and the cost can be reduced.

According to the third aspect of the present invention, the constant current control circuit includes the drive circuit, the constant current circuit, and the volume control circuit. Therefore, dimming can be performed stably and with a simple configuration. .

According to the fourth aspect, since the polarity reversing circuit includes the oscillation circuit and the polarity switching circuit, the polarities of the electrodes can be reliably switched at regular intervals, which contributes to extending the life of the fluorescent tube. it can.

[Brief description of drawings]

FIG. 1 is a block diagram of a light control device.

FIG. 2 is a power input circuit diagram.

FIG. 3 is a voltage doubler / voltage generator circuit diagram.

FIG. 4 is a switching power supply circuit diagram.

FIG. 5 is a full-wave rectification circuit diagram.

FIG. 6 is a voltage doubler rectifier circuit diagram.

FIG. 7 is a drive circuit diagram.

FIG. 8 is a constant current circuit diagram.

FIG. 9 is a volume control circuit diagram.

FIG. 10 is an oscillator circuit diagram.

FIG. 11 is a polarity switching circuit diagram.

FIG. 12 is a starting circuit diagram.

[Explanation of symbols]

 1 Power Input Circuit 2 Double Voltage High Voltage Generation Circuit 3 Switching Power Supply Circuit 4 Full Wave Rectifier Circuit 5 Constant Current Control Circuit 6 Polarity Inversion Circuit 7 Starting Circuit

Claims (4)

[Scope of utility model registration request] 1. A power supply input circuit incorporating an AC ballast,
Double voltage high voltage generation circuit for initial discharge of fluorescent lamp connected to this power supply input circuit, switching power supply circuit connected to power supply input circuit for both filament driving and control, and power supply input circuit Connected to the rectifier circuit for converting alternating current to direct current, a constant current control circuit connected to this rectifier circuit, and connected to this constant current control circuit, for switching the polarity of the fluorescent tube every certain time A fluorescent light dimming device comprising a polarity reversing circuit and a starting circuit connected to the polarity reversing circuit to determine the polarity for initial discharge. 2. The fluorescent lamp light control device according to claim 1, wherein a feedforward system is adopted as the switching power supply circuit. 3. The fluorescent lamp light control device according to claim 1, wherein the constant current control circuit includes a drive circuit, a constant current circuit, and a volume control circuit. 4. The fluorescent lamp light control device according to claim 1, wherein the polarity reversing circuit includes an oscillation circuit and a polarity switching circuit.