CN2262790Y

CN2262790Y - High-power factor low-distortion electronic balast

Info

Publication number: CN2262790Y
Application number: CN 95223185
Authority: CN
Inventors: 刘欢
Original assignee: XIGEMA GROUP CO XINJIANG
Current assignee: XIGEMA GROUP CO XINJIANG
Priority date: 1995-10-06
Filing date: 1995-10-06
Publication date: 1997-09-17
Anticipated expiration: 2005-10-06

Abstract

The utility model relates to a high-power factor low-distortion electronic ballast for fluorescent lamps. The utility model is composed of a rectification circuit, a power factor adjustment circuit, an oscillation circuit, and an abnormal state protection circuit, wherein, the power factor adjustment circuit is connected between the rectification circuit and the oscillation circuit, and the power factor adjustment circuit is composed of an integrated circuit, a mutual inductance booster, a switching tube, and resistor and capacitor elements. The utility model has the advantages of reasonable circuit design, high power factor (lambda is higher than 0.99), low harmonic content (THD is less than 10%), and small output voltage ripple. The lamp voltage is not changed following the fluctuation of input voltage, the service life of the lamp tube is extended, and reliability and stability of operation are enhanced. The utility model is a high-grade electronic ballast.

Description

High Power Factor low-distortion electronic ballast

The utility model High Power Factor low-distortion electronic ballast belongs to other class electric lighting field not to be covered, is a kind of electric ballast that is used for fluorescent lamp.

It is the narrower spike of a width that existing electric ballast adopts diode rectification to fit into input current with big capacity electrochemical capacitor filtering, contains more harmonic wave composition; Power factor is low, cause bigger infringement to electrical network and consuming device, the electric ballast that adopts by the stream filtering mode is also arranged, can improve power factor, reduce harmonic content, but higher harmonic content is still very big, mains ripple is bigger, cause the modulating voltage of fluorescent tube and the crest ratio of lamp current to exceed requirement, influence luminous efficiency and lamp tube service life.

The purpose of this utility model is to avoid the deficiencies in the prior art and adopts the active power factor adjustment technology, and a kind of power factor height is provided, and harmonic content is low, fluorescent tube long service life, stability and the high electric ballast of reliability.

The purpose of this utility model reaches by following measure; it is by rectification circuit; oscillating circuit; abnormal state protection circuit is formed; after rectification circuit and before the oscillating circuit, be connected with power factor and adjust circuit; it is by integrated circuit (IC) that power factor is adjusted circuit; mutual inductance stepup transformer B1 and switching tube Q1 and other Resistor-Capacitor Unit constitute; voltage after the rectification is through R1; send into the input of the multiplier of IC after the R2 dividing potential drop; the output voltage of mutual inductance stepup transformer B1 is through R12; be admitted to the amplifier in of IC after the W1 dividing potential drop; by signal of amplifier output another input to multiplier; send into the comparator of IC behind the signal that input voltage the is relevant signal multiplication relevant with output voltage; one end of switching tube links to each other with mutual inductance stepup transformer B1 output; link to each other with 7 pin of IC behind the one end series resistance R6; the comparator of IC is compared with the voltage of IC the 4th pin; and being voltage on the R6 that is in series by the Q1 switching tube, 4 pin voltages determined; as long as the electric current of Q1 reaches certain value; comparator is closed Q1 with regard to output signal by driving output; the peak current that makes Q1 is with the variation of combining input current voltage; switch by Q1 makes the envelope ripple of the switching current of mutual inductance stepup transformer B1 be proportional to AC-input voltage, is level and smooth sine curve.

For improving fluorescent tube useful life, enhanced stability and reliability, a step is improved the performance of electric ballast to the greatest extent, adopt the full electronic preheat starting circuit, it forms delay circuit by triode T4 resistance capacitance, the MOC photoelectrical coupler, switching tube Q2 and bridge rectifier are formed switching circuit, delay circuit links to each other with the rectification circuit output end of major loop, through the R13 current limliting, is charged to C9 by R14, triode T4 ends, MOC output ends, since the effect of the case position of R16, switching tube Q2 conducting, after the C9 charging finishes, triode T4 conducting, MOC exports conducting, and switching tube Q2 ends, realized preheating to filament, the delay circuit triode links to each other with photoelectrical coupler, and behind switching tube Q2, bridge rectifier links to each other with the filament two ends.Lamp tube ends voltage is risen rapidly, make lamp tube starting, realized pipeline start up by preheating,, warm-up time and preheat curent can be adjusted to comparatively desirable state by adjusting resistance R 14 and R15.

The utility model circuit design is reasonable, can reach the requirement of the high-grade electric ballast of GB requirement, the high λ of power factor＞0.99, harmonic content is hanged down THD＜10%, the output voltage pulsation is little, and modulating voltage does not change with the fluctuation of input voltage, has improved the useful life of fluorescent tube, having strengthened the reliability and stability of work, is a kind of high-grade electric ballast.

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

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

As shown in drawings; the utility model is by rectification circuit; power factor is adjusted circuit; oscillating circuit; abnormal state protection circuit; the filament pre-heating start-up circuit is formed; electric main is via C1; after pi type filter that C2L forms and negative tempperature coefficient thermistor NTC constitute the shock resistance circuit; through bridge rectifier; obtain the half-sinusoid direct voltage; between rectification circuit and oscillating circuit, be connected with power factor and adjust circuit; voltage after the rectification is given R1; link to each other with the tripod of integrated circuit (IC) after the R2 dividing potential drop; through the output voltage of mutual inductance stepup transformer B1 through R12; link to each other with the 1st pin of integrated circuit (IC) after the W1 dividing potential drop; voltage on integrated circuit (IC) the 4th pin is that the voltage on the R6 that is in series with switching tube Q1 determines; as long as the electric current of Q1 reaches certain value; comparator drives output with regard to output signal and closes Q1; thereby the peak current that guarantees Q1 is with the variation of combining input current voltage; power factor is adjusted circuit output and is linked to each other with the oscillating circuit input; by triode T1; T2; T3 and resistance; inductance; the oscillating circuit that electric capacity is formed is connected the filament two ends with abnormal state protection circuit; on the capacitor C 17 that connects at filament output two ends and connect preheat starting circuit; it is by triode T4 resistance; electric capacity is formed delay circuit; switching tube Q2; MOC river electric coupling rectification circuit is formed switching circuit; delay circuit links to each other with the rectification circuit output end of major loop; the triode T4 of delay circuit links to each other with photoelectrical coupler MOC; pass through switching tube Q2 after bridge rectifier links to each other with the filament two ends; supply with delay circuit with main circuit power; by photoelectrical coupler time delayed signal is sent to Q2; conducting by Q2 and ending; realization reaches the effect of pipeline start up by preheating to the control of open circuit voltage.

Claims

1. High Power Factor low-distortion electronic ballast; it is by rectification circuit; oscillating circuit; abnormal state protection circuit is formed; it is characterized in that after rectification circuit with before the oscillating circuit, being connected with power factor adjustment circuit; it is by integrated circuit (IC) that power factor is adjusted circuit; mutual inductance stepup transformer and switching tube Q1 and Resistor-Capacitor Unit constitute; voltage after the rectification is through R1; send into the input of the multiplier of IC after the R2 dividing potential drop; the output voltage of mutual inductance stepup transformer is given R12; send into the amplifier in of IC after the W1 dividing potential drop; one end of switching tube links to each other with the output of mutual inductance stepup transformer, links to each other with 7 pin of IC behind the end series resistance R6.

2. High Power Factor low-distortion electronic ballast according to claim 1, it is characterized in that forming preheat starting circuit by delay circuit, photoelectrical coupler, switching tube and bridge rectifier, delay circuit links to each other with the rectification circuit output end of major loop, charge to C9 by R14 through the R13 current limliting, the triode of delay circuit links to each other with photoelectrical coupler, behind switching tube Q2, link to each other with the filament two ends through bridge rectifier.

3, High Power Factor low-distortion electronic ballast according to claim 1 and 2, it is characterized in that the pi type filter be made up of C1, C2L and negative tempperature coefficient thermistor NTC constitute the shock resistance circuit and be connected rectification circuit before.