CN2171191Y

CN2171191Y - Electronic ballast for fluorescent lamp

Info

Publication number: CN2171191Y
Application number: CN 93243888
Authority: CN
Inventors: 蒋辛
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-11-03
Filing date: 1993-11-03
Publication date: 1994-07-06
Anticipated expiration: 2003-11-03

Abstract

The utility model relates to an electronic ballast for fluorescent lamps, belonging to the technical field of electric illumination uncovered by other classes. The electronic ballast is composed of an input filtering protection circuit, a rectifying filtering circuit, a power switch circuit, a driving and protection circuit and a filament load circuit. In the driving and protection circuit, two large volume capacitors C2, C3 are added based on a self-excited oscillation circuit. Making use of the power storage method of the capacitors, the switch time of a triode is widened. As the saturated process of the charging of the capacitors, slow start is realized. Meanwhile, the method of driving a choking integration penta-coil nonsaturnated transformer B2 is adopted. Thus, when the fluorescent lamps are switched on, the phenomena of surge current and cathode sputter are effectively prevented. The service life of the electronic ballast is guaranteed, and the service life of the luminous tubes is prolonged.

Description

Electronic ballast for fluorescent lamp

The utility model belongs to other class electric lighting field not to be covered, especially a kind of electric ballast that is used for fluorescent lamp.

At present, the electronic ballast for fluoresent lamp of domestic and international existing multiple model, generally be by current rectifying and wave filtering circuit, the sawtooth waveforms circuits for triggering, the three-winding drive circuit, power switch circuit, choke circuit, several parts of load filament loop are formed, though they have energy-conservation, noiselessness, but characteristics such as low-voltage startup, but also exist simultaneously because the lamp tube ends blackout that starter causes rapidly, shortcomings such as lamp tube service life reduction, in addition, two switch triodes in the existing electric ballast are because multiple factor is easy to generate second breakdown and series connection conducting phenomenon, its stability and reliability are reduced, shortened the useful life of electric ballast.

The purpose of this utility model be to provide a kind of reasonable in design, functional reliability strong, the electric ballast of good energy-conserving effect, fluorescent lamp that cost is low.

The purpose of this utility model reaches by following measure: this electric ballast is made up of input filter protective circuit, current rectifying and wave filtering circuit, power switch circuit, driving and protective circuit and filament load circuit; in driving and protective circuit; abandoned the saw-tooth wave generating circuit that constitutes by diac; what adopt is on the basis of self-maintained circuit, adds two large bulk capacitance C ₂And C ₃, capacitor C ₂Be connected on triode V ₀₁Excitation coil n ₃And n ₄Between, capacitor C ₃Be connected on triode V ₀₂Emitter and its excitation coil n ₆Between, form by resistance R ₁, coil n ₃, capacitor C ₂And R ₄, n ₆, C ₃The triode V that forms ₀₁And V ₀₂The drive circuit of series connection vibration energy storage form, this drive circuit utilizes the mode of capacitor-discharge to widen the ON time of triode, and along with the charging saturation history of electric capacity, has realized slow startup; In addition, in driving and protective circuit, the integrated five coil unsaturated transformer B of driving chokes have also been adopted ₂, be about to oscillatory feedback coil and choking-winding together, except traditional n with same backbone winding ₃, n ₆, n ₇Outside the three-winding, increased n ₄, n ₅Coil, wherein n ₄, n ₅, n ₇The end of the same name of coil links to each other, and the different name end is connected on triode V respectively ₀₁Emitter, V ₀₂Collector electrode and an end of filament, n ₄, n ₅The polarity of coil is opposite, goes here and there respectively in the work loop of two triodes, has prevented that not only electric current flows through triode V simultaneously in the same way ₀₁And V ₀₂, and, strengthened reliability because ending of another triode quickened in the existence of anti-phase electromotive force, reduced energy consumption.

Electric ballast by the such scheme manufacturing, owing to adopted the drive circuit of vibration energy storage form, surge current and cathodic sputtering phenomenon when fluorescent lamp is turned on light have been overcome effectively, simultaneously owing to adopted integrated five coil transformers of driving chokes, its functional reliability is strengthened, can guarantee its useful life and prolonging lamp tube service life, but this electric ballast also have advantages such as compact conformation, reasonable in design, good energy-conserving effect, the low low-voltage startup of cost.

Accompanying drawing is an embodiment circuit diagram of the present utility model.

The utility model is described in further detail below in conjunction with drawings and Examples:

As shown in the figure, this electric ballast is by fuse F, high frequency filter B ₁Form the input filter protective circuit, by rectifier bridge V _1-4, capacitor C ₁Form current rectifying and wave filtering circuit, by triode V ₀₁, V ₀2 form power switch circuit, by resistance R ₁To R ₆, diode V ₅, V ₆, capacitor C ₅, C ₂, C ₃And transformer B ₂Form driving and protective circuit, by capacitor C ₄, C ₆, coil n ₇Form the filament load circuit.In driving and protective circuit; different with the existing drive circuit of using always is not adopt the saw-tooth wave generating circuit that is made of diac; this circuit instantaneous trigger starts, and filament fails to give heat, easily causes the cold conditions sputter of filament metal; turned black in early days in fluorescent tube end two ends; this circuit causes continuous trigger when clamping diode damages in addition, and switch triode series connection conducting is burnt; so the utility model has adopted in self-maintained circuit, add two large bulk capacitance C ₂And C ₃, capacitor C ₂Be connected on triode V ₀₁Excitation coil n ₃And n ₄Between, capacitor C ₃Be connected on triode V ₀₂Emitter and its excitation coil n ₆Between, form by resistance R ₁, coil n ₃, capacitor C ₂And R ₄, n ₆, C ₃The triode V that forms ₀₁And V ₀₂The drive circuit of series connection vibration energy storage form, in the drive circuit of this energy storage form, n ₃, n ₆The induced voltage that provides directly puts on capacitor C ₂And C ₃On, being fit to the required store energy of excitation in electric capacity, the ON time of utilizing the mode of capacitor-discharge to widen triode, and along with the charging saturation history of electric capacity, realize slowly starting, thereby the fail safe of triode and lamp works is strengthened, energy consumption further reduces.In addition, in driving and protective circuit, the integrated five coil unsaturated transformer B of driving chokes have also been adopted ₂, be about to oscillatory feedback coil and choking-winding together, except traditional n with same backbone winding ₃, n ₆, n ₇Outside the three-winding, increased n ₄, n ₅Coil, wherein n ₄, n ₅, n ₇The end of the same name of coil links to each other, and the different name end is connected on triode V respectively ₀₁Emitter, V ₀₂Collector electrode and an end of filament, n ₄, n ₅The polarity of coil is opposite, goes here and there respectively in the work loop of two triodes, has prevented that not only electric current flows through triode V simultaneously in the same way ₀₁And V ₀₂, and because ending of another triode quickened in the existence of anti-phase electromotive force, make the trailing edge of waveform steeper, reduced the loss of triode, temperature rise descends, energy consumption decreases, the stability of triode and reliability strengthen, simultaneously, owing to adopted integrated five coil transformers of driving chokes, saved the vibration magnet ring, thereby reduced cost, the volume of whole ballast also dwindles thereupon, is easier to promote.

In addition, two switch triodes of this electric ballast are fastened on the metal shell, utilize metal shell to make radiator, save heating panel, and simultaneously, this shell also plays shielding action, and the interference that electric ballast is produced reduces greatly.

The operation principle of this electric ballast can be sketched and be: after civil power 220V connects, through fuse F and high frequency filter B ₁After the filtering, add to rectifier bridge V _1-4Two ends are through rectification and C ₁After the filtering, the A point obtains the working power of about 300V direct voltage as electric ballast, triode V during beginning ₀₁, V ₀₂All end, 300V voltage is through R ₂, n ₃, C ₂, n ₄, n ₅, R ₅, n ₆, C ₃Series arm is respectively to C ₂, C ₃Charging is because R ₅, n ₆, C ₃C in parallel on the branch road ₅, make U _BC＞U _AB, promptly As time goes on, C ₃The two ends charging makes its both end voltage rate of climb greater than C ₂The speed that both end voltage rises is worked as C ₃Both end voltage is greater than V ₀₂Cut-ff voltage the time, V ₀₂At first conducting, electric current is through C ₄, filament, C ₆, n ₇, n ₅, V ₀₂Form the loop, filament is given heat, because transformer B ₂Coupling, coil n ₇The induced potential of last generation is coupling in n ₆End of the same name on, make V ₀₂Enter the saturation conduction state rapidly, simultaneously also because n ₃, n ₄Induced potential opposite, make V ₀₁Keep cut-off state, n ₄Existence make V ₀₁That ends is rapider thorough, more As time goes on, and by C ₄, C ₆, n ₇, n ₅The series resonant tank electric current that constitutes reduces gradually, and charging process finishes, at this moment n ₆The undertension of last induction is with excitation V ₀₂, V ₀₂Begin to end, because B ₂Coupling, n ₃On produced and n ₆Opposite voltage makes V ₀₁Enter conducting state, by C ₄, C ₆, n ₇, n ₄The series resonant circuit that constitutes passes through V ₀₁Discharge, n ₅Existence make V ₀₂That ends is rapider thorough, works as n ₃Induced voltage be not enough to encourage V ₀₁The time, V ₀₁End.n ₅On anti-phase induced voltage make V ₀₂Conducting, circulation forms stable oscillation stationary vibration so repeatedly, at V ₀₁Emitter, V ₀₂Collector electrode output high frequency square wave, fluorescent tube is connected on this by C ₄, C ₆, n ₇In the series resonant circuit that constitutes, before starter not, C ₆Two ends produce higher resonance potential, and filament flows through and gives thermocurrent, tube starting under both actings in conjunction, n behind the starter ₇Playing ballast does in order to stablize the operating current of fluorescent tube, C ₆As bypass High-frequency Interference and the radiation that prevents noise.In addition, by R ₃, V ₅And R ₆, V ₆Constitute V respectively ₀₁And V ₀₂Protective circuit, give n respectively ₃, C ₂And n ₆, C ₃Reverse continuous current circuit is provided, has also avoided peak-inverse voltage to V simultaneously ₀₁, V ₀₂The infringement that emitter junction causes, capacitor C ₅Except that above-mentioned startup effect, work as V ₀₂When ending, also play and avoid too high voltages to make it to puncture, protection triode V ₀₂Effect.

Claims

1, a kind of electronic ballast for fluoresent lamp; it is made up of input filter protective circuit, current rectifying and wave filtering circuit, power switch circuit, driving and protective circuit and filament load circuit; it is characterized in that in driving and the protective circuit; what adopt is on the basis of self-maintained circuit, adds two large bulk capacitance C ₂, C ₃, capacitor C ₂Be connected on triode V ₀₁Excitation coil n ₃And n ₄Between, capacitor C ₃Be connected on triode V ₀₂Emitter and its excitation coil n ₆Between, form by R ₁, n ₃, C ₂And R ₄, n ₆, C ₃The triode V that forms ₀₁And V ₀₂The drive circuit of series connection vibration energy storage form; In addition, the integrated five coil unsaturated transformer B of driving chokes have also been adopted ₂, be about to oscillatory feedback coil and choking-winding together, except traditional n with same backbone winding ₃, n ₆, n ₇Outside the three-winding, increased n ₄, n ₅Coil, wherein n ₄, n ₅, n ₇The end of the same name of coil links to each other, and the different name end is connected on triode V respectively ₀₁Emitter, V ₀₂Collector electrode and an end of filament.

2, electric ballast according to claim 1 is characterized in that two switch triode V ₀₁, V ₀₂Be fastened on the metal shell, utilize it to make radiator, save heating panel, simultaneously, this shell also plays shielding action.