CN2387696Y - Electronic ballast with noel preheating circuit - Google Patents

Abstract

The utility model relates to an electronic ballast with a novel preheating circuit, which is composed of an outer shell, a conventional electronic circuit. That is the electronic ballast comprises a bridge rectifier circuit, a filter circuit, a high frequency generating and control circuit, etc. The utility model is characterized in that the electronic ballast is provided with a novel voltage current double clamped preheating circuit; resonance voltage and current added on lamp filaments before a fluorescent lamp is illuminated are simultaneously clamped on the setting preheating level thresholds; the cold breakdown of the fluorescent lamp caused by exorbitant resonance voltage or the cathodic sputtering caused by oversize preheating current is prevented. The advance blackening of both ends of the lamp tube is avoided; the service life of the lamp tube is prolonged.

Description

The electric ballast that has novel preheat circuit

The utility model relates to the improvement of electric ballast.

Existing electric ballast generally is not with preheat circuit, cold puncture when causing fluorescent lamp to be opened; Some has preheat circuit, also only hold with PTC thermistor or PTC crosstalk and carry out preheating, its weak point is: 1, and voltage and current peak that fluorescent lamp is added on the filament when opening are too high, cause cathode disintegration, make filament impaired, lamp tube ends is turned black too early, has influenced the useful life of fluorescent tube, 2, PTC is in the conduction and the condition of high temperature all the time during fluorescent lamp operation, has both increased power consumption, also influences the life-span.

The purpose of this utility model provides a kind of dual electric ballast of clamping down on preheat circuit of novel voltage electric current that has, can carry out soft starter after the preheating to Filament of fluorescent lamp with comparatively ideal wave mode, and preheat circuit is in complete cut-off state behind fluorescent lamp lighting, reduced power consumption, eliminate the blackout phenomenon of lamp tube ends, prolonged the useful life of fluorescent tube and ballast itself greatly.

Technical solution of the present utility model is: it is made up of shell and conventional electrical circuit etc., promptly comprise bridge rectifier circuit, filter circuit, high frequency generation and control circuit etc., novel preheat circuit is formed by voltage suppressor spare, thermistor, capacitances in series that (wherein electric capacity also can omit, but effect is poor slightly), voltage suppressor spare can adopt high-frequency high-power bi-directional voltage stabilizing pipe, discharge tube, Transient Voltage Suppressor etc.When opening fluorescent lamp, novel preheat circuit makes resonance frequency reduction, resonance potential owing to the effect of voltage suppressor spare is clamped on the preheating level threshold of setting, thereby produce the preheat curent of a comparatively ideal circular-arc wave mode on the inherent at the appointed time Filament of fluorescent lamp, fluorescent tube was lighted after this preheat curent made Filament of fluorescent lamp produce suitable thermionic emission, all elements of lighting in the preheat circuit of back promptly are in complete cut-off state, do not have any additional power consumption, elements such as PTC all are in cold conditions.Adopt this preheat circuit, can avoid the cathode disintegration phenomenon substantially, the switch life that makes filament is brought up to 50,000 to 150,000 times (experimental result) from general 7,000 times, has reached theoretical boundary.

The utility model is described in further detail below in conjunction with accompanying drawing with by embodiment:

Accompanying drawing is a line map, be novel preheat circuit in the frame of broken lines, preheat circuit is composed in series by D1, R1, C2, wherein D1 is voltage suppressor spare (can adopt high-frequency high-power bi-directional voltage stabilizing pipe, discharge tube, Transient Voltage Suppressor etc.), R1 is the PTC thermistor, C2 is an electric capacity, and preheat circuit is attempted by on the primary electron ballast capacitor C in parallel with the fluorescent lamp two ends 1.Because the synergy of D1, R1, three elements of C2, when opening fluorescent lamp, the voltage of lamp tube ends is clamped on the pre-set threshold (be generally normal condition 1/4～1/5), so on filament, set up the preheat curent of a comparatively desirable circular-arc wave mode, the parameter of D1, R1, C2 can be by Theoretical Calculation and experiment decision, is example with the fluorescent lamp of 40W, D1=180～200V, R1=60Q, C2=0.047 μ/160V.

Claims (2)

1, a kind of electric ballast that has novel preheat circuit, form by shell and conventional electrical circuit etc., promptly comprise bridge rectifier circuit, filter circuit, high frequency generation and control circuit etc., it is characterized in that electric ballast has the dual preheat circuit of clamping down on of a kind of novel electric current and voltage, preheat circuit is attempted by on the primary electron ballast capacitor C in parallel with the fluorescent lamp two ends 1, and fluorescent lamp is added in before lighting on the preheating level threshold that resonance potential on the filament and electric current be clamped at setting simultaneously.

2, by the described electric ballast of claim 1, it is characterized in that preheat circuit is the two-terminal element that is composed in series by voltage suppressor D1, thermistor R1 and capacitor C 2 (or only by D1, R1), D1 can adopt the bi-directional voltage stabilizing pipe, put pipe electricity or Transient Voltage Suppressor etc., and preheat circuit is attempted by on the primary electron ballast capacitor C in parallel with the fluorescent lamp two ends 1.