CN2385496Y

CN2385496Y - Electronic ballast for fluorescent lamp

Info

Publication number: CN2385496Y
Application number: CN 98243182
Authority: CN
Inventors: 惠华清
Original assignee: Individual
Current assignee: Individual
Priority date: 1998-05-12
Filing date: 1998-10-20
Publication date: 2000-06-28
Anticipated expiration: 2008-10-20

Abstract

The utility model discloses an electronic ballast for fluorescent lamps. A pulse transformer of a self-excitation type series resonant circuit and an electric inductor for resonance ballasting are simplified into one transformer B, a magnetic ring is left out and the bad influence of the magnetic ring to the circuit stability is lightened. Two waveform correction capacitors C1 and C2 are bridged between the input end and the corresponding output end of a rectification circuit, the wave peak ratio of the lamp current is reduced, and consequently, the early blackening of lamp tubes is slowed up. The base resistors of two oscillation tubes change the large design principle of the common technology that two equal resistors are arranged, and a base resistor R5 of a triode VT1 and a base resistor R6 of a triode VT2 can not be equal; by adjusting the size of the resistor R5, the voltage Uec of the two triodes is balanced, and consequently, the work of circuits is stable and reliable.

Description

Electronic ballast for fluoresent lamp

The utility model relates to a kind of fluorescent lamp ballast, particularly electronic ballast for fluorescent lamps.

Present known electronic ballast for fluoresent lamp has five parts and forms: 1. diode D ₁～D ₄, capacitor C ₁The full-bridge rectification filter circuit of forming; 2. resistance R ₁～R ₆(wherein: R ₅=R ₆), capacitor C ₂, trigger tube D ₆, triode VT ₁, VT ₂, and the auto-excitation type series connection oscillating circuit formed of magnet ring pulse transformer B; 3. inductance L ₁, capacitor C ₄, C ₅The resonance of forming starts ballasting circuit; 4. diode D ₅, capacitor C ₃, resistance R ₂The waveform correction circuit of forming; 5. fluorescent tube.This electric ballast need use the magnet ring pulse transformer, and circuit reliability is poor; Lamp current waveform is not good, and fluorescent tube easily turns black; The voltage U ec imbalance of triode, circuit easily burns.

The purpose of this utility model is to provide a kind of work more reliable, and lamp current waveform is good, the voltage U ec balance of triode, stable and reliable operation electronic ballast for fluoresent lamp.

The purpose of this utility model is achieved in that it is by 1. diode D ₁～D ₄, capacitor C ₃The full-bridge rectification filter circuit of forming; 2. resistance R ₁, capacitor C ₁, C ₂And C ₄The waveform correction circuit of forming; 3. triode VT ₁And VT ₂, diode D ₅, capacitor C ₅～C ₆, resistance R ₂～R ₆, the auto-excitation type series resonant circuit formed of vibration ballast transformer B and 4. fluorescent tube totally four partly form.Its circuit has saved magnet ring pulse transformer L, and the pulse transformer of auto-excitation type series resonance oscillating circuit and resonance ballast inductance device are simplified to a transformer; The input of rectification circuit with corresponding output cross-over connection two waveform correction electric capacity (C1) and (C2); Make resistance R ₅With R ₆Unequal, adjust R ₅Or R ₆Size make triode VT ₁, VT ₂Voltage U ec balance.

Owing to taking above-mentioned technical scheme, not only saved magnet ring in the circuit, reduced cost, also unexpectedly find to have improved the waveform of transistor base pumping signal in the experiment, make circuit working more reliable, stable; The voltage U ec balance of two triodes, electric capacity (C ₁) and (C ₂) played the waveform correction effect, improved the waveform of lamp current, prolonged the useful life of lamp.

Below in conjunction with drawings and Examples the utility model is further specified.

Fig. 1 is the utility model electronic ballast for fluoresent lamp.

Fig. 2 is that public electric ballast (is seen " Power Electronic Circuit is selected " book P ₃₈₅The Electronic Industry Press).

Fig. 3 is second embodiment of the present utility model.

Fig. 4 is the 3rd embodiment of the present utility model.

Fig. 5 is the 4th embodiment of the present utility model.

During enforcement, diode D ₁～D ₅Select 1N4007 type rectifier diode for use, wherein diode D ₁～D ₄Be connected into the full-bridge type rectification circuit, diode D ₅With triode VT ₂E knot oppositely and connect.Capacitor C ₁And C ₂With withstand voltage 400 volts Leaded Ceramic Disc Capacitor, capacity is below thousands of picofarads, present embodiment select for use the Leaded Ceramic Disc Capacitor of 82 picofarads, respectively with diode D ₂, D ₃And connect, promptly be connected across between the output and corresponding input end of rectification circuit.Capacitor C ₃Capacity be 0.47～22 microfarad, withstand voltage be 400 volts electrochemical capacitor, select for use in the present embodiment 4.7 microfarads, withstand voltage be 400 volts electrochemical capacitor, be connected to rectification output end, resistance R ₁Select 1/4 watt 470 kilo-ohms fixed carbon resister for use, capacitor C ₄Selecting capacity for use is 2200 microfarads, withstand voltage 630 volts electric capacity of the dacron, and the two all is attempted by triode VT ₁E, c between.Three utmost point VT ₁And VT ₂Select DK51 type switching tube for use, the resistance R of its emitter series connection ₂, R ₃Select the fixed carbon resister in 1/4 watt of 5.1 Europe for use; The resistance R of its base stage series connection ₅, R ₆For tens of Europe to hundreds of Europe, in adjustment, determine, should make triode VT ₁, VT ₂Voltage U ec balance be as the criterion the R in this example ₅Select the fixed carbon resister in 1/4 watt of 51 Europe for use, R ₆Select the fixed carbon resister in 1/4 watt of 27 Europe for use.Starting resistance R ₄Select 1/4 watt 300 kilo-ohms fixed carbon resister for use, be connected to triode VT ₂C knot; Start capacitor C ₆Selecting capacity for use is number microfarads, withstand voltage 50 volts electrochemical capacitor, concrete numerical value determines in adjustment, should make to start to turn on light transient current at below 2.5 times of lamp steady operation electric current, selects 4.7 microfarads, withstand voltage 50 volts electrochemical capacitor in the present embodiment for use, its negative pole connects common port, and positive pole meets L ₂Capacitor C ₅Select for use capacity be 33000 picofarads, withstand voltage be 630 volts electric capacity of the dacron, a termination triode VT ₁Collector electrode, another termination fluorescent tube; Capacitor C ₇Select for use capacity be 2700 picofarads, withstand voltage be 630 volts electric capacity of the dacron, connect with filament.Transformer B can select for use enamelled wire coiling on Φ 5 " I " type hollow coil holder of Φ 0.21～0.51 Φ to form L according to the size of making electronic ballast for fluoresent lamp power ₁And L ₂The number of turn be 12 circles, the number of turn of L3 is 1200 circles; When wiring, should note distinguishing end of the same name, guarantee to form positive feedback and open the work of shaking.

Further combined with Fig. 3, Fig. 4, Fig. 5 implementation issue of the present utility model is described again below.

The utility model and all is suitable in other various types of circuit of electronic ballast in three embodiment of Fig. 3, Fig. 4, Fig. 5, and its technique effect is constant.The first, they all can unite two into one pulse transformer and ballast inductance device, the cancellation magnet ring; The second, in the output and the corresponding input end cross-over connection capacitor C of rectification circuit ₁And C ₂Improve the crest ratio of lamp current; The 3rd, triode VT ₁And VT ₂With base resistance R ₅And R ₆Unequal, make two triode voltage U ec balances, can also use an an amount of colour coding inductance substitutional resistance R ₅, R ₆Or and resistance R ₅, R ₆After the series connection again place in circuit all can, even effect is better, it not only with series resistance R only ₅, R ₆Equally have the effect of balance pipe voltage U ec, also have the effect of the waveform of improvement.Other component parameters among three embodiment of Fig. 3 to Fig. 5 is identical with public technology with circuit connecting mode, does not slightly give unnecessary details.

Claims

A kind of electronic ballast for fluoresent lamp, by full-bridge rectification filter circuit, waveform correction circuit, auto-excitation type series resonance oscillating circuit and fluorescent tube totally four parts form, it is characterized in that having saved in the circuit magnet ring pulse transformer L, the pulse transformer of auto-excitation type series resonance oscillating circuit and resonance ballast inductance device are simplified to a transformer; The input of rectification circuit with corresponding output cross-over connection two waveform correction electric capacity (C ₁) and (C ₂); Make resistance R ₅With R ₆Unequal, adjust R ₅Or R ₆Size make triode VT ₁, VT ₂Voltage U ec balance.