CN2343739Y

CN2343739Y - Frequency conversion electronic ballast

Info

Publication number: CN2343739Y
Application number: CN 98231405
Authority: CN
Inventors: 李卫阳
Original assignee: Individual
Current assignee: Individual
Priority date: 1998-09-29
Filing date: 1998-09-29
Publication date: 1999-10-13
Anticipated expiration: 2008-09-29

Abstract

The utility model relates to a frequency conversion electronic ballast, which is composed of a field effect switching tube M1, a field effect switching tube M2, a capacitor C1, a capacitor C2, an inductor I1, and a frequency conversion drive circuit comprising a commutation filtering circuit, a start circuit, and a frequency conversion forming circuit. When used, the utility model is matched and connected with a fluorescent lamp or an energy saving lamp tube. When the utility model works, a relatively high frequency is used, and then a normal lower frequency can be changed into. The utility model solves the problems of preparatory heating and start of a lamp tube. When preparatory heating is carried out, the voltage of both ends of a lamp tube is low. Cold emission and start with a high voltage can be eliminated, small impact to a filament can be realized, and the service life of a lamp tube can be prolonged. Relay contacts are not adopted, failure rate can be reduced, and very reliable operation can be realized.

Description

The freq-variable electronic ballast

The utility model relates to a kind of electronic-circuit device that is used for fluorescent lamp control, particularly a kind of freq-variable electronic ballast.

In fluorescent lamp circuit and electronic energy-saving lamp circuit, in order to bring into play the normal useful life of fluorescent tube, must adopt pre-heated start-up circuit, promptly earlier add certain electric current to filament, after making its preheating, add that to lamp tube ends high voltage makes it starter again, can eliminate the filament pop-up like this, give full play to the MaLS of fluorescent tube.The prior art solution, generally be to adopt semistor Rt (as Fig. 1) or relay J (as Fig. 2) respectively resonant capacitance C2 to be shunted or short circuit, allow filament flow through certain electric current and reduce lamp tube ends voltage, make filament pre-heating, subsequently, because the thermistor resistance increases or relay disconnects, lamp tube ends voltage is raise, so tube starting.But above-mentioned two kinds of settling modes exist following shortcoming.Employing thermistor mode, owing under the thermistor normal temperature certain resistance is arranged, sometimes lamp tube ends voltage has reached starting voltage when preheating, still can cause pop-up, and when starter, damage because of the overtension that is added in the thermistor two ends makes thermistor easily, cause C2 among Fig. 1 by short circuit, so that bigger electric current is added on the filament for a long time, and fluorescent tube is damaged; Employing relay mode, not only its circuit is comparatively complicated and relay is not a solid-state element, has mechanical contact, and dependability is relatively poor, and its volume is bigger again, is unfavorable for miniaturization.

At the above-mentioned defective that prior art exists, the purpose of this utility model, but be provide a kind of prolonging lamp tube useful life the freq-variable electronic ballast of reliable operation again.

Solution of the present utility model is as follows.Still include field effect transistor switch pipe M1 and M2, capacitor C 1 and C2 and inductance I1 referring to Fig. 3, its circuit, and its feature part is, has the frequency conversion drive circuit that is connected with M2, capacitor C 1 and inductance I1 with field effect transistor switch pipe M1.

The utility model with foregoing circuit structure, with thermistor or the relay contact cancellation that is connected in parallel on resonant capacitance C2 two ends of the prior art, and replace general drive circuit of the prior art, and reach the purpose of pipeline start up by preheating in the mode of the so-called frequency conversion drive of another kind with the frequency conversion drive circuit.So-called frequency conversion drive mode promptly is that electric ballast is used higher frequency operation earlier, and then changes over normal frequency work.During power connection, switching tube M1 and M2 are in the higher frequency operation state, because frequency is higher, and the L in the resonant circuit, C off-resonance frequency, make the C both end voltage lower, do not reach the starting voltage of fluorescent tube DG, and there is electric current to flow through filament through L, C this moment, makes it preheating, through behind the certain hour, electric ballast enters normal operating conditions, and L, C produce resonance, and fluorescent tube DG both end voltage is raise until starter.

Therefore the utility model has solved the preheating starter problem of fluorescent lamp, electricity-saving lamp well, compares with conventional art, and have following characteristics: the impact to filament during startup is very little, prolonged the useful life of filament; During preheating, lamp tube ends voltage is lower, has eliminated pop-up, and the life-span of active material is prolonged greatly, thereby has prolonged the useful life of fluorescent tube; Cancelled relay contact, significantly reduced failure rate, it is very reliable to work.

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

Fig. 1 and Fig. 2 are the existing embodiment that adopts the electric ballast of general drive circuit.

Fig. 3 adopts the electric functional-block diagram of frequency conversion drive circuit for the utility model;

Fig. 4 is Fig. 3 a kind of more specifically embodiment of circuit of the present utility model.

As previously mentioned, in circuit shown in Figure 1, the two ends of resonant capacitance C2 are parallel with thermistor R1; And in circuit shown in Figure 2, resonant capacitance C2 two ends are parallel with the normally-closed contact of relay J.

Referring to Fig. 3, circuit of the present utility model still comprises field effect transistor switch pipe M1 and M2, capacitor C 1 and C2 and the inductance I1 that is had among Fig. 1 and Fig. 2, and its feature part is, has the frequency conversion drive circuit that is connected with M1, M2, C1 and I1.

Referring to Fig. 4 and Fig. 3, the frequency conversion drive circuit includes the current rectifying and wave filtering circuit of being made up of diode D1 to D4 and electrochemical capacitor E1, by diode D7, bidirectional diode D8, resistance R 1 to R4 and capacitor C 3 and the start-up circuit that C4 forms, form circuit with the frequency conversion that D6, voltage-stabiliser tube Z1 and Z2, controllable silicon T1, resistance R 5 to R8 and electrochemical capacitor E 2 form by transformer B1, diode D5.The end of the positive output end of D1, D4 and E1 and R1, C4, all drain electrode and C1 one end with M1 joins, the end of R3 and R4 links to each other with the source electrode of M1 and M2 respectively, coil L1 and the L3 of the end of the other end of R1, R3, C4, the negative pole of D7, R2, the positive pole of D5 and B1, all join with the drain electrode of M2, the end of R5 links to each other with the grid of M1, and the end of D8 and R6 all joins with the grid of M2, and the anodal of the L3 of B1 and D6 all joins with I1.M1 and M2 can adopt IRF840.

When the utility model with foregoing circuit structure specifically uses,, and fluorescent lamp or energy-saving lamp tube DG and circuit of electronic ballast joined from the input input 220V alternating voltage of its current rectifying and wave filtering circuit.The power supply input is carried out rectification through D1-D4, E1 filtering, and M1 and M2 form half-bridge circuit.Compare with traditional circuit, the coil L3 of driving transformer B1 has centre cap, and signal is through D5 and D6 rectification, and again through the Z1 voltage stabilizing, because B1 is the driven saturated transformer, added voltage-time of its coil is long-pending to be certain value.When rigidly connecting energize, through D5, D6, E1 the positive and negative half cycle of L3 is carried out voltage stabilizing, because the voltage stabilizing of Z1 value is higher, so the operating frequency of this moment is higher, make the filament of fluorescent tube DG be in low pressure and the preheat mode of electric current is arranged, subsequently, electric capacity E2 is charged by R8, when reaching the trigger voltage of T1, the T1 conducting is connected voltage-stabiliser tube Z2 and Z1 is in open-circuit condition, because the voltage stabilizing value of Z2 is lower than Z1, so after Z2 connected, electric ballast entered the low frequency operation state, fluorescent tube DG both end voltage is raise until starter.

Claims

1, a kind of freq-variable electronic ballast that is used for fluorescent lamp control, its circuit includes field effect transistor switch pipe M1 and M2, capacitor C 1 and C2 and inductance I1, it is characterized in that having the frequency conversion drive circuit that is connected with M2, capacitor C 1 and inductance I1 with field effect transistor switch pipe M1.

2, freq-variable electronic ballast as claimed in claim 1, it is characterized in that, the frequency conversion drive circuit includes the current rectifying and wave filtering circuit of being made up of diode D1 to D4 and electrochemical capacitor E1, by diode D7, bidirectional diode D8, resistance R 1 to R4 and capacitor C 3 and the start-up circuit that C4 forms, form circuit with the frequency conversion that D6, voltage-stabiliser tube Z1 and Z2, controllable silicon T1, resistance R 5 to R8 and electrochemical capacitor E2 form by transformer B1, diode D5.