CN202035203U - Novel electronic ballast capable of resisting surge current - Google Patents

Abstract

The utility model discloses a novel anti-surge current electronic ballast, which includes a rectifier circuit connected to an AC power supply and a PTC thermistor connected in parallel with a relay connected in series between the AC power supply and the rectifier circuit. Anti-surge current circuit; and the electronic ballast is connected with a filter electrolytic capacitor and a voltage conversion circuit at the output end of the rectification circuit, the positive pole of the electrolytic capacitor is connected to the starting terminal of the voltage conversion circuit, and the output of the voltage conversion circuit is connected to the relay drive end. When the electrolytic capacitor is charged to a certain level, the voltage conversion circuit starts to reduce the rectified DC voltage and provide it to the relay, which makes the relay close, short-circuits the thermistor, and eliminates the effect of the thermistor, thereby effectively resisting the surge current .

Description

A new electronic ballast with anti-surge current

technical field

The utility model relates to a circuit structure of an electronic ballast, in particular to a circuit structure design suitable for anti-surge current of a high-power electronic ballast.

Background technique

When the electronic ballast is turned on, a large inrush current will be generated due to the charging of the filter capacitor. The surge current is very harmful, it will blow the fuse of the electronic ballast, and it may also damage other components and cause the electronic ballast to fail.

Traditional electronic ballasts reduce the input surge current by connecting the input power supply in series with the NTC thermistor, and the current passes through the NTC thermistor. The NTC thermistor has a certain resistance at room temperature, thereby reducing the surge current. After the surge current passes , The resistance of NTC thermistor is reduced to a small value as the temperature rises, and no longer affects the current.

However, with the rapid development of electronic ballast technology, the power is getting bigger and bigger, and the voltage range it can adapt to is getting wider and wider. As shown in Figure 1, when the power of the electronic ballast exceeds 400W, the operating current of the electronic ballast is very large, and the current passing through the NTC thermistor is very large, and the NTC thermistor is no longer applicable if the current parameters cannot be satisfied. ; And when the power of the electronic ballast is very large, the capacity of the electrolytic capacitor is also very large, and the resistance of the NTC thermistor is reduced to a small hour, but the electrolytic capacitor continues to charge, and the current on the line is still very large. In addition, when NTC thermistors are used as anti-surge devices, when multiple electronic ballasts are turned on at the same time, tripping occurs due to the large impact current, especially when the electronic ballasts are turned off after a period of use. The internal temperature of the ballast is still very high, the resistance value of the NTC is still very small, the surge current is very large, and the switch blade cannot be pushed up. Therefore, a more effective, reliable and simple solution is needed to reduce the surge current of the electronic ballast.

Contents of the invention

In view of the above-mentioned defects in the prior art, the purpose of this utility model is to propose a new electronic ballast with anti-surge current, to solve the problem of surge current in high-power electronic ballasts, and to improve the electronic ballast The circuit and performance of the electronic ballast make the electronic ballast work more safely and reliably.

The above-mentioned purpose of the utility model will be achieved through the following technical solutions:

A novel anti-surge current electronic ballast, the electronic ballast includes a rectification circuit connected to an AC power supply, and is characterized in that a PTC thermistor and a relay are connected in series between the AC power supply and the rectification circuit An anti-surge current circuit formed in parallel; and the electronic ballast is connected with a filter electrolytic capacitor and a voltage conversion circuit at the output end of the rectification circuit, the positive pole of the electrolytic capacitor is connected to the starting terminal of the voltage conversion circuit, and the voltage The output of the transformation circuit is connected to the relay driving end.

The application and implementation of the electronic ballast of the present utility model, its outstanding effect is:

The input power supply of the electronic ballast is connected in series with the anti-surge current circuit of the above-mentioned high-power electronic ballast, and the inrush current is effectively reduced; there is a certain delay from power-on to the normal operation of the electronic ballast. The subsequent circuit of the electronic ballast rectifier circuit can work normally; the voltage conversion circuit contains a protection circuit, which can shut off the output in abnormal conditions, and the relay is disconnected to cut off the power input of the electronic ballast, which improves the electronic ballast. device safety and reliability.

Description of drawings

Figure 1 is a schematic diagram of the circuit structure traditionally used in electronic ballasts to reduce inrush current;

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

Detailed ways

In order to more effectively solve the surge current problem of high-power electronic ballasts, this utility model adopts a new circuit structure to reduce the surge current of electronic ballasts, aiming at improving the circuit and performance of electronic ballasts, Make electronic ballasts work more safely and reliably.

As shown in Figure 2, it includes a PTC thermistor with a positive temperature coefficient, a relay connected in parallel with the PTC thermistor, a rectifier square bridge connected in series with the PTC thermistor and the relay, and a rectifier square bridge connected in parallel with the DC output terminal electrolytic capacitor and a voltage conversion circuit.

After the electronic ballast is connected to the AC power supply, due to the characteristics of the electrolytic capacitor C1, it will be short-circuited instantly. The PTC thermistor is connected in series with the AC power supply and has a certain resistance value, which effectively reduces the surge current. The temperature of the PTC thermistor will rise sharply, the resistance value will increase, and the current through the PTC thermistor will decrease quickly. Before the current decreases to 0, the electrolytic capacitor will be charged through the PTC thermistor, and the electrolytic capacitor will be charged to To a certain extent, the voltage conversion circuit starts, the output voltage makes the relay pull in, short-circuits the PTC thermistor, the PTC thermistor loses its function, the current flows through the relay, and the electronic ballast works normally. An anti-surge current circuit composed of a PTC thermistor and a relay connected in parallel is connected in series between the AC power supply and the rectifier circuit; and the electronic ballast is connected with a filter electrolytic capacitor and a voltage In the conversion circuit, the anode of the electrolytic capacitor is connected to the starting terminal of the voltage conversion circuit, and the output of the voltage conversion circuit is connected to the relay driving terminal.

The above is a detailed description of the features and implementation of the present utility model, but the content described above is not to limit the various forms of the present utility model, so any simple modifications and equivalents made to this example based on this technical solution Replacement and the formed technical solutions should all fall within the scope of protection claimed by this patent.

Claims (1)

1. the electric ballast of novel anti surge current, described electric ballast comprises the rectification circuit that is connected with AC power, it is characterized in that: be serially connected with the Antisurge current circuit that is composed in parallel by PTC thermistor and relay between described AC power and rectification circuit; And described electric ballast is equipped with electrolytic capacitor filter and voltage conversion circuit at the output of rectification circuit, and the positive pole of described electrochemical capacitor is connected to the start end of voltage conversion circuit, and voltage conversion circuit output is connected to the relay drive end.

Images