KR200241267Y1 - Ballasts for Electronic Fluorescent Lamps with Protection Circuits - Google Patents

Abstract

Electronic fluorescent ballasts with protection circuits are designed to be durable and reduce power consumption. The ballast of the present invention is configured to short the voltage induced in the secondary coil of a transformer that turns on the fluorescent lamp at the end of its operation or at the end of its lifetime to prevent application of voltage to the fluorescent lamp input terminal. Therefore, the present invention prevents unnecessary power consumption and overheating, and provides an effect of protecting fluorescent lamps and bases.

Description

Ballast for Electronic Fluorescent Lamps with Protection Circuit

The present invention relates to an electronic fluorescent ballast, and more particularly to an electronic fluorescent ballast that protects the fluorescent lamp and the device by blocking the induced voltage applied to the input terminal of the fluorescent lamp during the non-operation or end of life of the fluorescent lamp.

Fluorescent lamps are used in most homes and offices because they are more efficient and have a longer lifespan than incandescent bulbs, and are less dazzling and do not have a noticeable shade. In addition, the fluorescent ballast for the stable operation of the fluorescent lamp has a magnetic and electronic, and in terms of power consumption, most of the electronic is used.

However, in the case of using an electronic fluorescent ballast adopting a conventional switching method, after the malfunction of the fluorescent lamp or replacing the fluorescent lamp, the power is "off" and after about 10 to 20 seconds has elapsed, the power switch "on" (ON) "There is an inconvenience. In addition, when the fluorescent lamp is to be turned on at the end of the lifetime of the fluorescent lamp, power consumption of 10 to 20 W is generated when the fluorescent lamp is not lit, which causes overheating to the cathode of the fluorescent lamp, causing the fluorescent lamp to melt. .

Therefore, the object of the present invention, in view of this point, is to prevent unnecessary voltage consumption at the input terminal of the fluorescent lamp at the time of non-operation of the fluorescent lamp or at the end of its life, to reduce unnecessary power consumption, and to adopt a durable protection circuit It is to provide a ballast for electronic fluorescent lamps.

1 is a circuit diagram showing a circuit including a ballast for an electronic fluorescent lamp according to the present invention,

2 is a diagram illustrating a signal transformer of the half bridge circuit of FIG. 1;

3 shows output waveforms during ballast operation.

<Description of the symbols for the main parts of the drawings>

10: signal input terminal 20: half bridge circuit

30: ballast 40: signal output stage

41: fluorescent lamp OSC1 ~ OSC4: signal trans

The electronic fluorescent ballast employing the protection circuit of the present invention for achieving the above object is, in the electronic fluorescent ballast, a diode for rectifying the voltage induced in the transformer for lighting the fluorescent lamp, and smoothing the rectified voltage A capacitor, a voltage dividing resistor for dividing the smoothed voltage, a zener diode in which a zener breakdown voltage is exceeded by the voltage dividing resistor to increase current, and an SCR in which an operating voltage is applied to a gate by the zener diode. And a signal transformer connected to the anode of the SCR and shorted according to the conduction state of the SCR, to short the voltage induced in the transformer at the time of non-operation of the fluorescent lamp and at the end of its life to prevent application of voltage to the input terminal of the fluorescent lamp. A protection circuit is adopted.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 shows a circuit diagram including a ballast for an electronic fluorescent lamp according to the present invention. The circuit diagram shown in FIG. 1 is composed of a signal input terminal 10, a half bridge circuit 20, and a signal output terminal 40 for rectifying and smoothing the input power. The ballast 30 according to the present invention is further added. Included as. The signal input terminal 10 rectifies the input power using four diodes D1 to D4, and smoothes the rectified power using the two diodes D5 and D6 and the electrolytic capacitors C4 and C5. Obtain The half-bridge circuit 20 includes the signal transformers OSC1 to OSC4 as shown in FIG. 2 and a plurality of transistors Q1 and Q2 that cross each other by the signal transformers OSC2 and OSC3. The signal output terminal 40 is a resonant type connected in parallel to a transformer T1 for turning on a fluorescent lamp with a voltage induced by switching the transistors Q1 and Q2 of the half-bridge circuit 20 and the fluorescent lamp 41 in parallel. The capacitor C9 is provided. On the other hand, the ballast 30 is a diode (D10) for rectifying the voltage induced in the transformer (T1), the diode to the electrolytic capacitors (C11, C12), the anode to receive and discharge the induced voltage through the diode (D10) It is made of a silicon controled rectifire (SCR) Q3 connected to the signal transformer OSC1 through D13 and connected to a gate through the zener diode ZD1. An operation of the ballast for an electronic fluorescent lamp of FIG. 1 having such a configuration will be described in detail with reference to FIGS.

In FIG. 1, when a fluorescent light switch (not shown) is operated by a user, power is input to the signal input terminal 10 through a fuse in response thereto. The signal input terminal 10 rectifies the input power using four diodes D1 to D4. The signal input terminal 10 smoothes the rectified power using diodes D5 and D6 and electrolytic capacitors C4 and C5 to obtain a smooth DC voltage. The smoothed DC voltage is a resistance of the half-bridge circuit 20 ( It is induced in the transformer T1 of the signal output terminal 40 through R1 and the diode D14, and is also applied to the collector of the first transistor Q1. The first transistor Q1 and the second transistor Q2 having the collector connected to the emitter of the transistor Q1 are switched by the signal transistors OSC2 and OSC3 so as to cross each other and the voltage is applied to the transformer T1. In this case, the fluorescent lamp 41 is turned on.

When the fluorescent lamp 41 is turned on and used, but the lifetime of the fluorescent lamp 41 reaches the end, or when the fluorescent lamp 41 malfunctions, the primary side of the transformer T1 in the state where the fluorescent lamp 41 is not lit is turned on. The coil generates about twice the voltage as when the fluorescent lamp 41 is turned on. At this time, the ballast 30 is operated. The high voltage of the transformer T1 primary coil is induced by the transformer T1 secondary coil and rectified by the diode D10 in the ballast 30. The voltage rectified in the diode D10 is smoothed by the electrolytic capacitors C11 and 12, and the smoothed voltage is divided by the voltage dividing resistors R6 and R7. The voltage divider resistors R6 and R7 exceed the zener breakdown voltage of the zener diode ZD1 and the current rapidly increases in the zener diode ZD1. By the operation of the zener diode ZD1, an operating voltage (0.6V) is applied to the gate of the SCR Q3. The SCR Q3 then conducts in the reverse direction, and through the conducted SCR Q3, the diode D13 also conducts in the reverse direction. Thus, the voltage through the diode D13 is shorted at the first coil winding of the signal transformer OSC1, which is grounded, and the signal transformers OSC1 to OSC4 as shown in FIG. 2 are stopped. Since the signal transformers OSC1 to OSC4 stop operation, the transistors Q1 and Q2 also stop operation. Therefore, since the voltage induced in the secondary coil of the transformer T1 is shorted, the voltage applied to the input terminal of the fluorescent lamp 41 is cut off. In this way, the ballast 30 is prevented from applying a voltage to the input terminal of the fluorescent lamp 41.

Now, when the inoperative fluorescent lamp and the old fluorescent lamp are removed and replaced with a new fluorescent lamp, all the components are normally operated and the fluorescent lamp 41 is immediately turned on.

In this way, the voltage induced in the secondary coil of the transformer T1 is shortened by the operation of the ballast 30 at the end of the life of the fluorescent lamp 41 or in the inoperative operation, thereby preventing overheating of the device and melting of the fluorescent lamp.

3 shows output waveforms when the ballast 30 operates, and FIGS. 3A and 3C show output waveforms when the conventional ballast operates, and FIGS. 3B and 3D correspond to FIGS. 3A and 3C, respectively. This is the output waveform during ballast operation according to the design. As shown in Figures 3a and 3c, the output during the operation of the ballast is conventionally not shortened, but the output during the operation of the ballast according to the present invention is shorted as shown in Figures 3b and 3d.

As described above, the electronic fluorescent ballast employing the protection circuit of the present invention shortens the voltage induced in the transformer that turns on the fluorescent lamp at the end of the lifetime of the fluorescent lamp or prevents it from applying voltage, thereby reducing unnecessary power consumption. It prevents overheating and protects the device.

Claims (1)

In ballasts for electronic fluorescent lamps, A diode for rectifying the voltage induced in the transformer for lighting the fluorescent lamp; A capacitor for smoothing the rectified voltage; A voltage divider for dividing the smoothed voltage; A zener diode in which a zener breakdown voltage is exceeded by the voltage dividing resistor and the current increases; An SCR in which an operating voltage is applied to a gate to conduct the zener diode; And Including a signal transformer connected to the anode of the SCR and shorted according to the conduction state of the SCR, An electronic fluorescent ballast that employs a protection circuit that prevents voltage from being applied to the fluorescent lamp input terminal by shortening the voltage induced by the transformer at the time of non-operation of the fluorescent lamp and at the end of its life.