CN2371760Y

CN2371760Y - Electronic ballast with abnormal state protection function

Info

Publication number: CN2371760Y
Application number: CN 99228458
Authority: CN
Inventors: 盛章宝
Original assignee: Individual
Current assignee: Individual
Priority date: 1999-05-26
Filing date: 1999-05-26
Publication date: 2000-03-29
Anticipated expiration: 2009-05-26

Abstract

The utility model relates to an electronic ballast with an abnormal state protection function, which comprises bridge rectifiers D1-D4, a filtering capacitor C1, a trigger circuit composed of a trigger diode D5 and capacitors C2, C3, an oscillation circuit composed of switch tubes T1, T2, capacitors C4-C7, resistors R3-R7 and electrical inductors L1-L4. An abnormal protection circuit is composed of an electrical inductor L and a high voltage automatic switch K which are connected in series and are connected in parallel to the output end of the oscillation circuit that is both ends of the capacitor C7; the electrical inductor L is coupled with the electrical inductor L2 in the oscillation circuit.

Description

The electric ballast that has the abnormal condition protection function

The utility model relates to a kind of electric ballast, particularly the electric ballast that can protect when abnormality.

At present, commercially available electric ballast major part is to adopt first generation discrete component to form, and its line construction is simple, and cost is low, poor performance, and reliability is bad.The common people are considered as economize on electricity and do not save money.The bad reason of reliability mainly is aging or gas leakage because of fluorescent tube; and filament is intact; electric ballast still has output, alleged abnormality then occurs, and the voltage and current of output this moment is several times as much as the voltage and current behind the lamp tube starting; at this moment switching transistor is with breakdown; electric ballast promptly damages, and the only a few product has the abnormal condition protection function, but because of the circuit structure complexity; the cost height, sales difficulty.

Existing electronic ballast circuit is more; representative as Fig. 1; it is by bridge rectifier D 1-D4; filter capacitor C1; circuits for triggering; oscillating circuit; abnormity protection circuit is formed; wherein circuits for triggering are by diac D5 and capacitor C 2; C3; resistance R 2 constitutes; oscillating circuit is by switching transistor T1; T2; capacitor C 4-C7; resistance R 3-R7; inductance L 1-L4 constitutes, and abnormity protection circuit is by bridge circuit D6-D9, controllable silicon T3; voltage-stabiliser tube D10; D11; resistance R 8-R11; capacitor C 8 and inductance L 5 constitute, and wherein abnormity protection circuit inductance L 5 is connected with inductance coupling high in the oscillating circuit.When electronic ballast circuit and fluorescent tube H just often, the 220V civil power makes circuits for triggering work behind rectifying and wave-filtering, give triggering signal of oscillating circuit, oscillating circuit output high-frequency and high-voltage is lighted fluorescent tube H.When fluorescent tube H because of aging or gas leakage filament when intact again; abnormality can appear; be that the oscillating circuit output end voltage of drawing from capacitor C 7 is very high, the big voltage of this big electric current can damage the switching transistor T1 and the T2 of oscillating circuit, in order to prevent this phenomenon; inserted abnormity protection circuit; it makes controllable silicon T3 connect then inductance L 5 short circuits by high speed Zener diode regulator D11 when C7 voltage is very high; make the oscillating circuit failure of oscillation, reach the purpose of protection switch pipe T1, T2.But in real process, because the fluctuation of supply voltage, and the fluctuation of fluorescent tube startability; also can make the voltage at output C7 two ends of oscillating circuit very high,, can make abnormity protection circuit work equally because the charging rate of capacitor C 8 is very fast; cause misoperation, service behaviour is unreliable.

The purpose of this utility model is exactly in order to address the above problem, and provides a kind of reliable working performance and cost low, the effective electric ballast that has the abnormal condition protection function.

Technical solution of the present utility model:

A kind of electric ballast that has the abnormal condition protection function; it includes bridge rectifier D 1-D4; filter capacitor C1; circuits for triggering of forming by diac D5 and capacitor C 2, C3 and by switch transistor T 1, T2; capacitor C 4-C7; resistance R 3-R7; the oscillating circuit that inductance L 1-L4 forms; it is characterized in that abnormity protection circuit is made up of inductance L and high-voltage automatic switch K; inductance L is connected in series with high-voltage automatic switch K; the output that they are attempted by oscillating circuit is the two ends of capacitor C 7, and 2 couplings of the inductance L in inductance L and the oscillating circuit.

The utlity model has following advantage:

1, circuit structure is simple, and volume is little, is convenient to compact and adopts, and only needing increases an element at basic circuit, and available circuit is then wanted tens elements.

2, reliability height only occurs abnormality and just protects action, overcome misoperation appears in available circuit easily when supply voltage or the fluctuation of fluorescent tube starting performance defective.

3, produce debugging conveniently.

4, cost is low, and available circuit has increased more than ten element in basic high-frequency circuit, need several yuans, and the utility model has only increased an element in basic circuit, several maos, and manufacturer can digest in administrative expenses.Can extensively popularize and promote.

Fig. 1 is the electrical schematic diagram of existing electric ballast;

Fig. 2 is an electrical schematic diagram of the present utility model.

As Fig. 2; the utility model includes bridge rectifier D 1-D4; filter capacitor C1; circuits for triggering of forming by diac D5 and capacitor C 2, C3 and by switch transistor T 1, T2; capacitor C 4-C7; resistance R 3-R7; the oscillating circuit that inductance L 1-L4 forms; characteristics of the present utility model are; abnormity protection circuit is made up of inductance L and high-voltage automatic switch K; inductance L is connected in series with high-voltage automatic switch K, and the output that they are attempted by oscillating circuit is the two ends of capacitor C 7, and 2 couplings of the inductance L in inductance L and the oscillating circuit.

Above-mentioned high-voltage automatic switch K is and the similar structure of common starter for fluorescent, but bimetallic moving plate and the spacing between the stator in it are bigger, makes its auto-action under high pressure (greater than 350V) situation.Here; high-voltage automatic switch K is the key element in the circuit; and its operation voltage design is the key of K switch; if operation voltage is too high; it is unreliable then to protect; operation voltage is low excessively, then may cause the fluorescent tube point not work, and fluorescent tube dissimilar, different capacity is answered the high-voltage automatic switch of the different operation voltages of adapted.

Under normal circumstances, oscillating circuit output high voltage, this voltage are added in fluorescent tube H two ends, and fluorescent tube H is lighted, because the fluorescent tube pressure drop is usually at 100-150V, deficiency is so that high-voltage automatic switch K work, so abnormity protection circuit is inoperative under the normal condition.

During startup, the both end voltage of fluorescent tube H moment is very high, but because high-voltage automatic switch is the same with fluorescent tube H, has hysteretic properties, does not light work with K switch so still do not influence fluorescent tube H, can not make the K switch misoperation.Just because of this characteristic, even when occurring voltage fluctuation or fluorescent tube startability fluctuation situation in the circuit, fluorescent tube H still can normally be lighted, and high-voltage automatic switch K can misoperation.

When filament is intact when the aging or gas leakage of fluorescent tube occurring; this moment, fluorescent tube H can not be lighted; then the high-frequency and high-voltage of oscillating circuit output just all is added in high-voltage automatic switch K and goes up (this voltage is generally more than 350V); therefore; K is auto-closing under the high pressure effect; make inductance L produce the inductance (inductance L 1, L2, L3 generally are wound on together) that oscillating circuit is given in an electromotive force negative feedback, thus make the oscillating circuit failure of oscillation, thus reach in the purpose that protection switch pipe T1, T2 under the abnormality occur.

The utility model is useful in equally on the electric ballast of High Power Factor or on the electric ballast of filament pre-heating type and uses, the former just inserts an angle of flow again and enlarges circuit on DC circuit, the latter then only inserts the resistance of a positive temperature coefficient at output circuit.After they are connected to abnormity protection circuit of the present utility model, has good abnormal condition protection function equally.

Claims

1, a kind of electric ballast that has the abnormal condition protection function; it includes bridge rectifier D 1-D4; filter capacitor C1; circuits for triggering of forming by diac D5 and capacitor C 2, C3 and by switch transistor T 1, T2; capacitor C 4-C7; resistance R 3-R7; the oscillating circuit that inductance L 1-L4 forms; it is characterized in that abnormity protection circuit is made up of inductance L and high-voltage automatic switch K; inductance L is connected in series with high-voltage automatic switch K; the output that they are attempted by oscillating circuit is the two ends of capacitor C 7, and 2 couplings of the inductance L in inductance L and the oscillating circuit.

2, by the described electric ballast that has the abnormal condition protection function of claim 1; it is characterized in that described high-voltage automatic switch K adopts and the similar structure of starter for fluorescent; bimetallic moving plate in it and the spacing between the stator strengthen, and make its auto-action under high-pressure situations.