CN201207748Y - Electric ballast - Google Patents

Abstract

Disclosed is a preheating startup circuit, which relates to various types of electronic ballasts for fluorescent tubes, comprising an EMC filter circuit, a rectifier circuit, a correction circuit, a conversion circuit and a delay startup circuit. The EMC filter circuit receives the external input power to process the electromagnetic interference signals, and is connected with the rectifier circuit. The rectifier circuit is connected with the correction circuit which is used to improve the power factor correction to provide a stable voltage to the conversion circuit. The conversion circuit transforms the AC low voltage to high frequency high voltage. Due to the adoption of preheating delayed startup technology, the service life of the fluorescent lamp and electronic rectifier is greatly prolonged, thereby reducing the lamp <black end> phenomenon to ensure the circuit works stably in long term.

Description

an electronic ballast

1. Technical field

The utility model belongs to the field of lighting equipment manufacturing, in particular to an electronic ballast for fluorescent lamp tubes.

2. Background technology

With the continuous development of "green lighting", major developed countries and some developing countries in the world have successively formulated "green lighting" plans, and have achieved remarkable results. In fact, the quality and level of lighting has become an important indicator of social modernization.

As a new lighting source, fluorescent lamps have been widely promoted and applied due to their small size and high luminous efficiency. With the continuous development of electronic technology and semiconductor technology, electronic ballasts developed on the basis of high-frequency conversion technology are gradually becoming mature and perfect, and will quickly replace traditional inductive ballasts with an inevitable trend. At present, fluorescent lamps generally start in a cold state, but due to the extremely low impedance of the filament, a large current occurs at the moment of turning on, which shortens the life of the lamp tube and seriously threatens the life of the electronic ballast, especially when a high-power fluorescent lamp starts. Shock waves are more likely to damage devices and equipment, which is not conducive to the development of electronic ballasts.

At present, although there is a circuit technology for increasing filament preheating and starting, most of the means use the thermistor shunt. The disadvantage is that the thermistor itself will generate heat. After multiple starts, the thermistor itself is also easily damaged. For this reason, it is necessary to improve the current filament preheating technology to achieve the purpose of increasing the service life of the lamp tube.

3. Contents of utility model

The utility model aims at the deficiencies of the above-mentioned prior art, and its main purpose is to provide an electronic ballast for fluorescent lamps, which has a preheating start function, further prolongs the service life of fluorescent lamps and electronic ballasts, reduces the blackhead phenomenon of lamp tubes, and ensures long-term operation of the circuit. work steadily.

In order to achieve the above object, the utility model adopts the following technical solutions:

An electronic ballast for fluorescent tubes, including an EMC filter circuit, a rectifier circuit, a correction circuit, a conversion circuit, a delay preheating start circuit, and an EMC filter circuit that receives an external input power source for processing electromagnetic interference signals and is connected to the rectifier circuit , to generate a smooth DC high voltage, and then connected to the correction circuit, the correction circuit is used for power factor correction to provide a stable voltage to the conversion circuit, the conversion circuit converts the AC low voltage to generate high frequency high voltage, the characteristic of this circuit is that it is used in the delay start circuit One R7 is connected in series in the trigger tube circuit, and R7 is a 0.25 watt 220 ohm resistor, and the charging capacitor capacity in the delay start circuit is increased to 50 volts and 100 microfarads.

Compared with the prior art, the circuit of the utility model has the advantages of fully preheating the filament before starting the fluorescent lamp, greatly prolonging the life of the lamp, improving the performance of the equipment and the instantaneous impact resistance, simple and practical circuit, and low manufacturing cost.

4. Description of drawings

Fig. 1 is a schematic block diagram of the utility model.

Fig. 2 is a schematic diagram of the specific circuit structure of the utility model.

5. Specific implementation

The practical circuit of the present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

The utility circuit makes improvements on the deficiencies of the above-mentioned prior art. The main purpose is to provide an electronic ballast for fluorescent lamps, which has the characteristics of preheating and starting, further prolonging the life of fluorescent lamps and electronic ballasts, reducing blackheads of lamp tubes, and ensuring long-term stable operation of circuits.

In order to achieve the above object, the utility model adopts the following technical solutions:

As shown in Figure 1 and Figure 2, the fluorescent lamp working circuit includes a fluorescent lamp and an electronic ballast, and the electronic ballast of the present utility model includes an EMC filter circuit (10), a rectifier circuit (20), a correction circuit (30), and a conversion circuit (50), delay start circuit (40), EMC filter circuit receives external input power, in order to process electromagnetic interference signal, is connected with rectification circuit, then the voltage after processing is input rectification circuit, rectification circuit is connected with calibration circuit, calibration The circuit is used to improve the power factor to provide a stable voltage to the conversion circuit, and the conversion circuit converts the AC low voltage to generate high frequency and high voltage.

As shown in Figure 2, an R7 is connected in series in the trigger tube circuit DB3 in the delay start circuit (40), and R7 is a resistance of 0.25 watts and 220 ohms, and the charging capacitor (C9) capacity in the delay start circuit (40) is 50 Volts 100 microfarads.

The working principle of the utility model is: in series with the low-resistance resistor R7 in the circuit of the bidirectional trigger tube DB3, it can effectively reduce the impact of the surge pulse current of the trigger circuit on DB3, and play the role of overcurrent and overvoltage limiting. , The capacity of the starting capacitor C9 of the sawtooth wave generator may be large. When the fluorescent lamp is turned on, the power supply passes through R1, (R1 is 0.5W/680K), and charges the starting capacitor C9. Properly increasing the capacity of C9 can prolong the preheating and starting time of the fluorescent lamp tube, so as to protect the fluorescent lamp tube the goal of.

Claims (1)

1, a kind of electric ballast of fluorescent tube, comprise the EMC filter circuit, rectification circuit, correcting circuit, change-over circuit, the time-delay preheat starting circuit, the EMC filter circuit receives outside input power supply, in order to handle the electromagnetic interference signal, be connected with rectification circuit, with the voltage input rectification circuit after handling, rectification circuit is connected with correcting circuit, correcting circuit is used for power factor correction to provide burning voltage to change-over circuit, change-over circuit produces high-frequency and high-voltage with the AC low-tension conversion, it is characterized in that: R7 of series connection in the trigger tube loop in the delayed startup circuit, R7 is the resistance in 0.25 watt of 220 Europe, and the charging capacitor capacity in the delayed startup loop is 50 volt of 100 microfarad.

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