CN2181794Y

CN2181794Y - Electronic ballast with anomalous state protection of lamp

Info

Publication number: CN2181794Y
Application number: CN 93246516
Authority: CN
Inventors: 陈孟仁; 郎正荣
Original assignee: SANWEI PLASTIC ELECTRIC APPLIANCE CO Ltd ZHENJIANG CITY
Current assignee: SANWEI PLASTIC ELECTRIC APPLIANCE CO Ltd ZHENJIANG CITY
Priority date: 1993-12-30
Filing date: 1993-12-30
Publication date: 1994-11-02
Anticipated expiration: 2003-12-30

Abstract

The utility model relates to an electronic ballast with an abnormal state protection device for florescent lamps. A main return circuit is composed of a power supply, a trigger and an LC oscillating return circuit comprising a switch triode. The utility model is characterized in that an abnormal state protection device is added into the main return circuit of an electronic ballast LC. The abnormal state protection device sampled from an inductance L clamps the base of the switch triode T2 of the LC oscillating return circuit under the abnormal condition that the power supply is on and the florescent lamps don't start. Adopting a single triggering circuit, a sample circuit, a delay circuit, the trigger and a clamping circuit, the electronic ballast can stop working under abnormal state and the ballast is effectively protected. Thus, the service life of the ballast is prolonged.

Description

Electronic ballast with anomalous state protection of lamp

The utility model relates to a kind of electric ballast with the lamp abnormal condition protection.

It is wide that existing electric ballast has operating voltage, energy-conservation, and advantages such as flicker free have obtained application more and more widely, yet, owing to be in that the major loop of ballast still vibrates under the abnormality when lamp, make T under abnormality ₁, T ₂Electric current to surpass normality doubly a lot of, thereby caused T ₁, T ₂Thermal breakdown, thereby, existing electric ballast, its life-span mostly is the life-span of a fluorescent tube most.

The purpose of this utility model is: by increase the shortcoming that an abnormal condition protection device overcomes existing ballast in the LC of electric ballast major loop; make electric ballast be in abnormal condition of lamp tube state following time; can stop ballast work; protect ballast effectively, prolonged the useful life of ballast.

Technical solution of the present utility model is achieved in that

A kind of electric ballast that is used for the band abnormal condition protection device of fluorescent lamp; have by power supply, trigger and contain the major loop that the LC oscillation circuit of switch triode constitutes; it is characterized in that: in the LC of electric ballast major loop, increase by one and take a sample from inductance L, and under the abnormality logical at power supply, that lamp is inoperative with the switch triode T of LC oscillation circuit ₂The abnormal condition protection device 6 of base stage clamp; protective device has single circuits for triggering 1, sample circuit 2, delay circuit 3, a trigger 4 and a clamp circuit 5; single circuits for triggering 1 are connected in parallel on the DC power supply two ends, the switch triode T of the other end of its trigger tube and LC oscillation circuit ₂Base stage connect the sample coil L of sampling loop 2 ₁With the coupling of vibration inductance L, its output is connected with delay circuit 3, and trigger 4 is connected between clamper 5 and the delay circuit 3, and clamper is by triode T ₃Form its clamp end and switch transistor T ₂Base stage connects, clamping reference termination main circuit power negative pole G.

Below in conjunction with accompanying drawing the utility model is elaborated.

The abnormal condition protection device 6 that the electric ballast of this band lamp abnormal condition protection increases in the LC major loop is made up of single circuits for triggering 1, sample circuit 2, delay circuit 3, trigger 4 and clamp circuit 5.

Behind the lamp electric power starting, power supply through rectification, filtering, pass through R ₂To C ₁, C ₂UA is worked as in charging〉UD ₁The time, diac D ₁Puncture C ₂Switch triode T is given in discharge ₂Base stage provides a triggering signal, makes the starting of oscillation of LC major loop, because C ₂Triggering T ₂In time, discharged, and C ₁The discharge, thereby this moment guaranteed UA＜＜UD ₁, promptly only produce triggering signal one time after the each power-on of this circuit.

When fluorescent tube just often, after the circuit starting of oscillation, with the coil L of inductance L coupling ₁The detected signal in two ends is through D ₁Rectification, R ₃Current limliting, C ₃, R ₄Time-delay, the UC of this moment ₃＜＜UD ₃, make T ₃End, do not influence the work of major loop, guaranteed the smooth build-up of luminance and the work of fluorescent lamp.

When fluorescent tube was in the disconnected abnormality of filament, because filament is disconnected, C broke from the loop with oscillating capacitance, so T ₁, T ₂Failure of oscillation has been protected ballast.

To be in filament intact when fluorescent tube, and when lamp did not activate the abnormality of (lamp does not start), because main circuit current is uprushed, this electric current was by L ₁Detect, through D ₂Rectification, R ₃Give C after the current limliting ₃Charging is not through making T ₁, T ₂After the time-delay of thermal breakdown takes place, make UC ₃UD ₃, make trigger tube D ₃Puncture C ₃Discharge is to T ₃Base stage applies a trigger current, makes T ₃Saturated rapidly, thereby with T ₂Base stage is clamped on low level, makes the major loop failure of oscillation, the failure of oscillation in loop, C ₃The result of discharge makes UC ₃＜UD ₃, thereby T ₃Base stage and can not get pumping signal, thereby T ₃Withdraw from saturatedly, but because loop failure of oscillation, as previously mentioned, the circuits for triggering of this ballast are the single circuits for triggering, thus have always UA＜＜UD ₁, this moment major loop in T ₂Base stage can not get the necessary triggering signal of starting of oscillation.Like this, the loop is in the failure of oscillation state always, thereby has protected ballast, have only abnormality to get rid of after, the turn on lights power supply just can make fluorescent lamp normally start work again.

When this electric ballast is in abnormal condition protection, minimum from the electric current of electrical source consumption because the major loop failure of oscillation, R wherein ₁Adding abnormality is got rid of after, accelerate C ₁Discharge, making abnormality get rid of the back circuit can start rapidly.

L in the utility model ₁For on L, add around coil, expense is cheap, is easy to make.

It is that abnormal condition protection is got ready that characteristics of the present utility model are by the single circuits for triggering, when entering abnormality, by the L in the sample circuit ₁Detect abnormality, and through time-delay, the effect of triggering and clamp circuit is with T ₂Clamp, thus make the major loop failure of oscillation, protected electric ballast, thereby possessed simple in structurely, with low cost, debug characteristics easily.

Claims

1, a kind of electric ballast that is used for the band abnormal condition protection device of fluorescent lamp; have by power supply, trigger and contain the major loop that the LC oscillation circuit of switch triode constitutes; it is characterized in that: in the LC of electric ballast major loop, increase by one and take a sample from inductance L, and under the abnormality logical at power supply, that lamp is inoperative with the switch triode T of LC oscillation circuit ₂The abnormal condition protection device 6 of base stage clamp; protective device has single circuits for triggering 1, sample circuit 2, delay circuit 3, a trigger 4 and clamp circuit 5, single circuits for triggering 1 and is connected in parallel on the DC power supply two ends, the switch triode T of the other end of its trigger tube and LC oscillation circuit ₂Base stage connect the sample coil L of sampling loop 2 ₁With the coupling of vibration inductance L, its output is connected with delay circuit 3, and trigger 4 is connected between clamper 5 and the delay circuit 3, and clamper is by triode T ₃Form its clamp end and switch transistor T ₂Base stage connects, clamping reference termination main circuit power negative pole G.

2, electric ballast according to claim 1 is characterized in that: the single circuits for triggering 1 in the protective device 6 discharge resistance R by one ₁, a current-limiting resistance R ₂, an isolation capacitance C ₁, one trigger capacitor C ₂With a trigger tube D ₁Form R ₁Two ends meet the positive pole and the negative pole G of main circuit power, R respectively ₂Connect the main circuit power positive pole, and C ₁After the series connection again and C ₂Series connection, C ₂Meet main circuit power negative pole G, trigger D ₁An end and C ₁, C ₂Point of contact A be connected the other end and switch triode T ₂Base stage be connected, adjust C ₁, C ₂Value, make under lower limit supply voltage condition U _AGreater than D ₁Trigger voltage UD ₁And provide enough trigger currents.

3, electric ballast according to claim 1 is characterized in that: the sampling loop 2 in the protective device 6 by with an end and the rectifier diode D of the sample coil L1 of vibration inductance L coupling ₂Series connection is connected coil L with R3 serial connection back again with delay circuit 3 ₁The other end and G join.

4, electric ballast according to claim 1 is characterized in that: the delay circuit 3 in the protective device 6 is by the R of parallel connection ₄And C ₃Form R ₄, C ₃Upper end and R ₃And trigger tube D ₃Link to each other R ₄, C ₃Lower end and G join.

5, electric ballast according to claim 1 is characterized in that: the trigger 4 in the protective device 6 is by diac D ₃And resistance R ₅Be in series, an end of trigger links to each other with delay circuit, triode T in the other end of trigger and the clamper ₃Base stage links to each other.

6, electric ballast according to claim 1 is characterized in that: the clamper 5 in the protective device 6 is a switch triode T ₃, the R in its base stage and the trigger ₅Connect, emitter links to each other with power cathode G, collector electrode and major loop switch triode T ₂Base stage is connected.