CN201270613Y

CN201270613Y - Electronic ballast for fluorescent lamp

Info

Publication number: CN201270613Y
Application number: CNU2008200386933U
Authority: CN
Inventors: 刘洪生; 甘同
Original assignee: Shenzhen tomwell Science & Technology Development Co Ltd
Current assignee: Shenzhen tomwell Science & Technology Development Co Ltd
Priority date: 2008-08-18
Filing date: 2008-08-18
Publication date: 2009-07-08
Anticipated expiration: 2018-08-18

Abstract

The utility model relates to a fluorescent lamp electronic amperite, which belongs to the switch power supply technical field. The amperite comprises a rectifier filter circuit whose input is connected with a power supply, wherein output of the rectifier filter circuit is connected with the input of a saw-tooth wave generating circuit, the saw-tooth wave generating circuit is composed of a current-limiting resistance which forms a tank loop and a non-electrochemical capacitor, wherein two ends of the current-limiting resistance and the non-electrochemical capacitor and contacts of the current-limiting resistance and the non-electrochemical capacitor are connected with the input of a double switching tube self-maintained circuit as the output of the saw-tooth wave generating circuit, and the output of the self-maintained circuit is connected with a fluorescent lamp. The fluorescent lamp electronic amperite has the advantages that the service life is long, the volume is small, the working temperature limit is high, stable and reliable, and the like.

Description

Electronic ballast for fluoresent lamp

Technical field

The utility model relates to a kind of ballast, and especially a kind of electronic ballast for fluoresent lamp belongs to the switch power technology field.

Background technology

Common tradition has the electric ballast kind of electrochemical capacitor more, comprise single tube topology, two-tube topology (push-pull type, two-tube semibridge system, double tube positive exciting formula, two-tube inverse-excitation type etc.), three pipe three-phase positive activation types, four pipe single-phase bridges or the like, wherein all need to use electrochemical capacitor.Its advantage is that the capacitance per unit volume amount of electrochemical capacitor is big, price is low.But electrochemical capacitor is compared with nonpolarity non-electrolytic capacitor, have many weakness, as: the life-span is short, heatproof is low, can not bear reverse voltage, bear overvoltage capabilities low, bear high peak current and the effective value current capacity is low, acid pollution is arranged, can not preserve for a long time etc.These weakness make existing ballast be difficult to satisfy long-life, user demand such as high temperature resistant.

The utility model content

The purpose of this utility model is: at the weakness that prior art exists, propose the electronic ballast for fluoresent lamp of a kind of stable and reliable for performance, long service life, no electrolytic capacitor that volume is little, thereby satisfy the constantly user demand of development.

In order to reach above purpose, electronic ballast for fluoresent lamp of the present utility model comprises that input connects the current rectifying and wave filtering circuit of power supply source, and the output of described current rectifying and wave filtering circuit connects the input of saw-tooth wave generating circuit, is used to provide direct current; Described saw-tooth wave generating circuit is made of current-limiting resistance that forms oscillation circuit and non-electrolytic capacitor, the intermediate contact of the two ends of described current-limiting resistance and non-electrolytic capacitor and described current-limiting resistance and non-electrolytic capacitor connects the input of dual switch self-maintained circuit as the output of saw-tooth wave generating circuit, is used to provide dual switch conducting pulse according to the order of sequence; The output of described self-maintained circuit connects fluorescent lamp, is used to provide fluorescent lamp starter high-frequency alternating current.

Like this, can realize all functions of ballast fully without electrochemical capacitor.Compared with prior art, the utlity model has the life-span long, volume is little, the warm limit for height of working, advantage such as stable, reliable.

Description of drawings

Below in conjunction with accompanying drawing the utility model is further described.

Fig. 1 is the circuit theory diagrams of the utility model embodiment one.

Fig. 2 is the circuit theory diagrams of the utility model embodiment two.

Embodiment

Embodiment one

The electronic ballast for fluoresent lamp of present embodiment as shown in Figure 1, the alternating current 220V power supply constitutes the bridge rectifier rectification through diode D1～D4, has filter circuit by capacitor C 1 through what diode D6 connect that C2 constitutes again, to the about 300V direct voltage of subsequent conditioning circuit output by the Passively compensated effect of ripple.The output of current rectifying and wave filtering circuit connects the input of saw-tooth wave generating circuit.This saw-tooth wave generating circuit is made of current-limiting resistance R1 that forms oscillation circuit and non-electrolytic capacitor C4, the intermediate contact of the two ends of current-limiting resistance R1 and non-electrolytic capacitor C4 and R1, C4 connects the input of dual switch self-maintained circuit as the output of saw-tooth wave generating circuit, is used to provide dual switch conducting pulse according to the order of sequence.Mainly by first and second (switch power) triode BG1, the BG2 of serial connection, pulse transformer T and series resonant circuit constitute the dual switch self-maintained circuit.Pulse transformer T by respectively with himself former limit winding N1 coupling forward winding N2 and oppositely winding N3 constitute, the base stage of described first and second triodes meets forward and reverse winding N2, N3 through resistance R 3, R4 respectively, constitutes HF switch loop separately.The intermediate contact of current-limiting resistance R1 and non-electrolytic capacitor C4 connects the base stage of second triode through two-way triggering diode ST, and this intermediate contact connects the series resonant circuit that inductance L 2 and capacitor C 8, C9 and filament constitute behind the former limit winding N1 of pulse transformer T.

After the energized, the 220V alternating current is exported about 300V direct voltage behind rectifying and wave-filtering, and this direct voltage charges to C4 through R1.When C4 two ends charging voltage surpassed the breakover voltage (about 32V) of ST, the ST conducting provided a narrow current impulse to BG2 pipe base stage, makes at first conducting of BG2.This moment, DC power supply was passed through the formation loops such as winding N1 of fluorescent tube filament, L2 and T, gave C8, C9 charging.Because the coil N1 of pulse transformer T is to forward winding N2 and the oppositely induction coupling of winding N3, the induced voltage that N2 produces will make the BG1 conducting, and the induced voltage on the N3 will make BG2 by.So C8, C9 form discharge loop by L2, N1 and BG1 again.Circulation so repeatedly, BG1, BG2 take turns conducting, the self-oscillation of the about 25kHz of very fast formation frequency.

After the starting of oscillation, C4 ceaselessly discharges through D8 and GB1, makes ST no longer produce trigger voltage, i.e. sawtooth generation circuit quits work.Simultaneously, the series resonant circuit generation resonance that high-frequency oscillation signal makes C8, C9 and L2 etc. constitute very soon, therefore the C8 capacity produces enough resonance potentials of height (about 500-600V) much larger than the C9 capacity at the C9 two ends usually, makes that fluorescent tube is disposable to start light.

In a single day fluorescent tube is lighted, series resonant circuit is off resonance then, and lamp tube ends voltage will be for about 100V, and L2 only plays metering function, and C8 then plays every straight effect, and the minimum electric current that C9 passes through plays the assistant heating effect to filament.

In addition, when BG2 by conducting become by the time, the self induction voltage of L2 and the voltage behind the power rectifier are superimposed, might make BG2 bear the high frequency voltage of kilovolt, this triode is punctured, and pressure limiting capacitor C 7 in parallel between lamp tube ends then can effectively reduce voltage for this reason.

Present embodiment is because BG1, BG2 are operated on off state, so can obtain very high efficiency.The series resonant circuit that inductance L 2 and C8, C9 etc. constitute then can while starter fluorescent tube and restriction lamp works electric current.

Embodiment two

Present embodiment as shown in Figure 2, its basic comprising is identical with embodiment one, difference is that filter circuit only is made of C1.

Experiment showed, that above embodiment can realize all functions of ballast fully without electrochemical capacitor, and the life-span is long, volume is little, the warm limit for height of working, stable, reliable.

In addition to the implementation, the utility model can also have other execution modes.All employings are equal to the technical scheme of replacement or equivalent transformation formation, all drop on the protection range of the utility model requirement.

Claims

1. An electronic ballast for fluorescent lamps, comprising a rectification filter circuit whose input is connected to a power supply, the output of the rectification filter circuit is connected to the input of a sawtooth wave generation circuit; it is characterized in that: the sawtooth wave generation circuit is composed of A current-limiting resistor and a non-electrolytic capacitor, the two ends of the current-limiting resistor and the non-electrolytic capacitor and the middle contact between the current-limiting resistor and the non-electrolytic capacitor are used as the output of the sawtooth wave generating circuit and connected to the dual-switch self-excited oscillation circuit input; the output of the self-excited oscillation circuit is connected to the fluorescent lamp.

2. The electronic ballast for fluorescent lamps according to claim 1, characterized in that: the self-excited oscillation circuit of the double-switch tubes is mainly composed of first and second triodes connected in series, a pulse transformer and a series resonant circuit.

3. The electronic ballast for fluorescent lamps according to claim 2, wherein the pulse transformer is composed of a forward winding and a reverse winding respectively coupled with its own primary winding, and the first and second three The bases of the pole tubes are respectively wound forward and reverse to form their own high-frequency switching loops.

4. The electronic ballast for fluorescent lamps according to claim 3, characterized in that: the middle junction of the current-limiting resistor and the non-electrolytic capacitor is connected to the base of the second triode through a bidirectional trigger diode, and the middle The contact point is connected to the series resonant circuit formed by the inductance, the capacitance and the filaments at both ends of the fluorescent tube after passing through the primary winding of the pulse transformer.

5. The electronic ballast for fluorescent lamps according to claim 4, characterized in that: the voltage limiting capacitors are connected in parallel between the filaments at both ends of the fluorescent lamp.