CN2175510Y

CN2175510Y - Electronic ballast for fluorescent lamp

Info

Publication number: CN2175510Y
Application number: CN 93239217
Authority: CN
Inventors: 马继波
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-09-03
Filing date: 1993-09-03
Publication date: 1994-08-24
Anticipated expiration: 2003-09-03

Abstract

The utility model relates to an electronic ballast for a fluorescent lamp, which is formed by that a mutual induction element L6 is connected between an L3 and a filament in series. An induction potential in an overvoltage and over-current detection coil L7 with a mutual induction to the mutual induction element L6 charges a rectification circuit, a filter circuit and a delay circuit. The induction potential on the L7 enlarges when the ballast is in an abnormal state, a bidirectional controllable silicon DO3 breaks down and switches into conduction, a controllable silicon T1 triggers and switches into conduction, which cause an oscillating circuit to stop oscillating, protect the crystal tube and induction element in the circuit of the ballast from being burnt and ensure the reliability of the electronic ballast for a fluorescent lamp.

Description

Electronic ballast for fluorescent lamp

The utility model is relevant with fluorescent lamp ballast, especially with have overcurrent, the electronic ballast for fluoresent lamp of overvoltage automatic protection functions is relevant.

Electronic ballast for fluoresent lamp is a kind of high light efficiency energy-conserving product, and it replaces existing iron inductance ballast, without starter and electric power compensation capacitor, have low-voltage and start noiselessness, no light stroboscopic, can reduce advantages such as disaster hidden-trouble, but its useful life is short, poor reliability.Its main cause is fluorescent lamp after illumination after a while, and fluorescent tube will wear out gradually, and aging serious fluorescent tube changes because of internal resistance, and the electric current that fluorescent tube flows through increases, lamp tube ends voltage raises, and the electric ballast components and parts is damaged lost efficacy.In addition, because lamp tube air leaking and filament is intact or filament on electronic emitting material reduce.Not enough so that inert gas conducting in the pipe, and the starter oscillation circuit of electric ballast is still in work, its components and parts are unable to bear the impact of high-voltage great-current, thereby cause electric ballast to damage.In addition, if the power supply overtension, certain phase voltage that produces during the three phase mains laod unbalance is too high, all will damage electric ballast.Because its reliability is not high, the popularization of electric ballast is restricted.

The purpose of this utility model provides a kind of long service life, the reliability height, and volume is little, and is in light weight, and cost hangs down the electronic ballast for fluoresent lamp that self-protection function is arranged under abnormal conditions.

The utility model is achieved in that

AC power is charged to capacitor C 3 through bridge rectifier, when the C3 charging voltage reaches the puncture voltage of bidirectional triode thyristor D6, and the D6 conducting, add trigger impulse for triode BG2 base stage, the BG2 conducting, electric current self-rectifying circuit V+ level is through C5, fluorescent wire, R8 and C6, Filament of fluorescent lamp, inductance component L 3, BG2 flows into the V-utmost point of rectification circuit, owing to flow through the electric current that increases gradually among the L3, negative induced potential and produce negative positive induced potential down in L4 just down on producing in the L5 of mutual inductance with it makes BG2 keep conducting, and BG1 ends, when electric current rising rate of change was reduced to zero gradually, BG2 ended, the BG1 conducting, capacitor C 5 is passed through BG1, L3, filament, R8 and C6, THE FILAMENT DISCHARGE AND, resonant tank flows through reverse current, thereby sets up self-oscillation, filament pre-heating, the R8 resistance in parallel with C6 increases, because frequency of oscillation and L3, the C6 series resonance frequency is close, causes loop resonance, produce high pressure in lamp tube ends, make fluorescent tube glow discharge, and then reach arc discharge, lamp starts.

Be in series with mutual-inductance element L6 between L3 and the filament, induced potential charges to CO2 after diode DO4 halfwave rectifier among the mutual-inductance element L7, voltage on the CO2 is less than the puncture voltage of bidirectional triode thyristor DO3, DO3 is connected between the control utmost point and CO2 of thyristor T1, and T1 is in cut-off state because of Triggerless.The last induced potential of L7 increases, and the charging voltage of CO2 increases, and through time-delay, reaches the breakdown voltage value of DO3, DO3 conducting, T1 triggering and conducting.The tap of L6 is through diode DO2, and T1 is connected to direct current V one-level, and no current passes through among the L3; make the oscillating circuit failure of oscillation; loop current drops to 0, thereby protective transistor and inductance element are not burnt out, in case the T1 conducting; because R1; DO1 supplies with T1 and enough keeps electric current, and T1 stream keeps conducting always, and the loop is starting of oscillation no longer; after disconnecting the input power supply, just can reset.

The puncture voltage of DO3 of the present utility model is 32V.

The utility model does not have perfect abnormal state protection circuit: when the fluorescent tube open circuit; promptly do not connect fluorescent tube or filament blow; the not starting of oscillation of transistor of the present utility model or the failure of oscillations; when fluorescent tube do not start or supply voltage too high; DO3 of the present utility model punctures; the protective circuit action makes the circuit failure of oscillations, avoids electric ballast to damage because of electric current is excessive.The utility model is through " China Testing Technology Institute " test, and every index all meets national standard, and wherein lamp abnormality contrast test is as follows:

1. when power supply voltage was higher than 260V, other electric ballast began serious heating, and the utility model is carried out protection automatically, and it is not serious to generate heat.

When filament intact, fluorescent tube serious aging, but lamp can also start the working condition when luminous, the serious heating of other electric ballast is so that damage, and the utility model is protected when fluorescent tube is aging serious automatically, can not damage.

When filament intact, when lamp tube air leaking or serious aging, lamp can't start, other electric ballast energized after 2-5 minute electric ballast promptly damage, and the utility model electric ballast is protected automatically, can not damage for a long time.

The utility model is compared with Inductive ballast, and power saving rate reaches 25%, owing to solved integrity problem, is suitable for large-scale popularization and uses.

Fig. 1 is circuit theory diagrams of the present utility model.

Following is embodiment of the present utility model:

Inductance L 1, L2, capacitor C 1 is formed the anti-dried circuit of scratching of high frequency, is connected on AC power and diode D1, D2, D3 is between the bridge rectifier that D4 forms.C2 is a filter capacitor.The R1 in parallel with C2 is that electric current is kept resistance.R2, C3, D6 forms start triggering circuit.Triode BG1, BG2 is responsible for for vibration.The D6 conducting adds trigger impulse, the BG2 conducting for the BG2 base stage.R3, R5 are BG1, the BG2 base resistance.R4, R6 are BG1, the BG2 emitter resistance.C5, C6, R8, L6, L3 forms oscillation circuit, and C4, R7 form the vibration compensating circuit.L4, L5 are BG1, BG2 base stage mutual inductor.R8 is for starting the preheating time delay resistance.D5, D7, D8, DO1 are discharge diode.L7 is the over-voltage and over-current magnetic test coil.DO4, RO1, CO2 forms rectification, filter delay circuit.DO3 is a bidirectional trigger diode.T1 is the one-way SCR element, can make the oscillating circuit failure of oscillation after the conducting.CO1 is anti-false triggering electric capacity.DO2 is an isolation diode.

Claims

1; electronic ballast for fluoresent lamp; charge to capacitor C 3 through bridge rectifier by AC power; when the C3 charging voltage reaches the puncture voltage of bidirectional triode thyristor D6; the D6 conducting; add trigger impulse for triode BG2 base stage; the BG2 conducting; electric current self-rectifying electric current V+ level is through capacitor C 5; Filament of fluorescent lamp; R8 and capacitor C 6; Filament of fluorescent lamp; inductance component L 3; BG2 flows into the V-level of rectification circuit; owing to flow through the electric current that increases gradually among the L3; just following negative induced potential in the L5 of mutual inductance with it, producing; negative positive induced potential down in the L4 of mutual inductance with it, producing; make BG2 keep conducting; BG1 ends; when electric current rising rate of change is reduced to zero gradually; triode BG2 ends; the BG1 conducting; when electric current rising rate of change is reduced to zero gradually; triode BG2 ends; the BG1 conducting; capacitor C 5 is passed through BG1; L3; filament; R8 and C6, THE FILAMENT DISCHARGE AND, resonant tank flows through reverse current; set up self-oscillation; make filament pre-heating, the R8 resistance in parallel with C6 increases, because frequency of oscillation and L3; the C6 series resonance frequency is close; cause loop resonance, produce high pressure, fluorescent tube is started in lamp tube ends; it is characterized in that being in series with between L3 and the filament mutual-inductance element L6; induced potential charges to CO2 after diode DO4 rectification among the L7 of mutual inductance with it, and the voltage on the CO2 is less than the puncture voltage of bidirectional triode thyristor DO3, and DO3 is connected between the control utmost point and CO2 of thyristor T1; T1 is in cut-off state because of Triggerless; increase when L7 goes up induced potential, the charging voltage of CO2 increases, through time-delay; reach the breakdown voltage value of DO3; the DO3 conducting, the T1 triggering and conducting, the tap of L6 is through diode DO2; T1 is connected to direct current V one-level; no current passes through among the L3, makes the oscillating circuit failure of oscillation, and loop current drops to zero; but protective transistor and inductance element are not burnt out; in case the T1 conducting, because R1, DO1 supplies with T1 and enough keeps electric current; T1 keeps conducting always; the loop is starting of oscillation no longer, after disconnecting the input power supply, just can reset.