CN2492037Y - Structure of rectifying effect protective circuit for fluorescent lamp electronic ballast - Google Patents
Structure of rectifying effect protective circuit for fluorescent lamp electronic ballast Download PDFInfo
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- CN2492037Y CN2492037Y CN 01246314 CN01246314U CN2492037Y CN 2492037 Y CN2492037 Y CN 2492037Y CN 01246314 CN01246314 CN 01246314 CN 01246314 U CN01246314 U CN 01246314U CN 2492037 Y CN2492037 Y CN 2492037Y
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Abstract
The utility model relates to a structure of a rectification protecting circuit for electronic ballast of fluorescent lamps. The prior art has the disadvantages of higher cost, untimely protection, and the like problem. A positive peak sample circuit of the tube voltage and a negative peak sample circuit of the tube voltage are connected with an adding circuit of positive and negative peaks which is connected with an absolute value comparator connected with a controlling circuit for stopping vibration. The utility model can judge if the fluorescent lamp is in the state of the rectification according to detect the asymmetry positive and negative amplitudes of the voltage drop of fluorescent lamps' alternating current. The utility model has the advantages of simple structure, lower cost, accurate and timely judgment, and wider applied range.
Description
The utility model is the structure of electronic ballast for fluoresent lamp rectifying effect protective circuit.
Fluorescent lamp is a kind of popular lighting source, and owing to its negative resistance charactertistic, must have corresponding ballast to match could operate as normal.Electric ballast is the electronic installation that a kind of newly-developed comes out, and its operating frequency is generally in tens KHz.Because operating frequency has been brought up to tens KHz by 50 or 60 hertz power frequency, makes electric ballast compare with traditional Inductive ballast and has higher efficient.
Fluorescent lamp is a kind of of gaseous discharge lamp.In the use of fluorescent lamp, aging day by day along with fluorescent tube, light tube electric voltage can increase gradually, and the thermionic emission ability of filament cathode also reduces gradually simultaneously.Because the degree of aging of two filaments of fluorescent tube can not be identical, cause the electron emissivity difference of two filament cathodes, make that the positive negative part of the alternating current flow through fluorescent tube is inequality, this shows that rectifying effect has appearred in fluorescent tube, that is to say that the life-span of fluorescent tube is about to termination.When rectifying effect appears in fluorescent lamp, the cathode fall at filament place can obviously increase, thereby make the temperature of filament electrode sharply increase, to make the glass tube walls fusing of filament electrode end when serious, or the light fixture connector at lamp holder place is burnt, thereby may cause serious consequences such as fire, simultaneously electric ballast was lost efficacy because of power output is excessive.Therefore in the design of electric ballast, must consider to add the rectifying effect protective circuit, could improve the reliability of system like this.
Existing fluorescent lamp rectifying effect protective circuit is to realize by the flip-flop that detects the lamp operating current.Fig. 1 is general fluorescent lamp rectifying effect protective circuit embodiment.V is a square-wave signal source among the figure, and L and C1 are series resonance inductance and electric capacity, and TX is an output transformer.R1, D1, R2 and D2 constitute the fluorescent tube equiva lent impedance, and when fluorescent tube did not have rectifying effect, the resistance of R1 and R2 equated that when rectifying effect appearred in fluorescent tube, the resistance of R1 and R2 was unequal.Sampling capacitance C2 is used to detect the flip-flop of lamp current.When rectifying effect appears in lamp, flow through in the alternating current of fluorescent tube and part flip-flop occurred, on capacitor C 2, produced the direct current pressure drop thus, when the EOL of control circuit IC end, when detecting this direct current pressure drop above certain set point, control circuit IC produces control signal corresponding, and electric ballast is quit work, thereby has avoided making the overheated phenomenon of filament electrode because of rectifying effect appears in fluorescent tube.
Though this rectifying effect protective circuit can be worked, its corresponding shortcoming is arranged also.
First, the flip-flop of lamp current owing to will sample, sampling capacitance C2 directly must be connected with fluorescent tube, so just can not realize the electrical isolation between electric ballast and the tube load, thereby limit the application in the occasion of some strict demand electrical isolation.If must use, then must increase and realize, thereby the cost of electric ballast is increased such as devices such as optocouplers in this occasion.
The second, because fluorescent tube is connected with sampling capacitance, making must increase an output transformer in circuit structure, thereby has increased the cost of electric ballast.
The 3rd; because sampling capacitance is connected with fluorescent tube; when operate as normal; lamp current can produce certain AC voltage drop on electric capacity; in order to prevent misoperation, must establish the comparative level among the control circuit IC higher, bring to such an extent that shortcoming is thus; have only when extremely serious rectifying effect appears in fluorescent tube protective circuit to move, and protective circuit can't be judged when fluorescent tube is in non-serious rectification attitude.
Because above-mentioned three shortcomings make this kind rectifying effect protective circuit have certain limitation on performance, have also limited the application on electric ballast.
The purpose of this utility model be a kind of protection of design promptly and accurately, cost is low, use wide electronic ballast for fluoresent lamp rectifying effect protective circuit.
The utility model is by light tube electric voltage positive peak sample circuit, light tube electric voltage negative peak sample circuit, and positive and negative peak voltage signal adder circuit constitutes.The fluorescent tube that is connected with electric ballast respectively with light tube electric voltage positive peak sample circuit, light tube electric voltage negative peak sample circuit connects.Positive and negative peak value sampling circuit is connected with positive and negative peak voltage signal adder circuit, and signal plus circuit is connected with the absolute value comparator, connects control failure of oscillation circuit at last.
Foregoing circuit needs fluorescent tube AC voltage drop dividing potential drop is obtained light tube electric voltage positive peak value and negative peak value respectively, treats positive and negative peak voltage signal addition after relatively judge, whether control circuit determines failure of oscillation.
Protective circuit structure of the present utility model can be Fig. 2, and promptly V is a square-wave signal source, and L and C1 are series resonance inductance and electric capacity.R1, R2, D1 and D2 constitute the fluorescent tube equiva lent impedance, and when fluorescent tube did not have rectifying effect, the resistance of R1 and R2 equated that when rectifying effect appearred in fluorescent tube, the resistance of R1 and R2 was unequal.Resistance R 3, R4, R5, R6, R7, R8, capacitor C 2, C3, C4, diode D3, D4, these elements have formed fluorescent lamp rectifying effect testing circuit, and detected signal is delivered to the EOL input of control circuit IC.
The operation principle of this circuit is the asymmetry by the positive and negative amplitude that detects the lamp AC voltage drop, thereby judges whether fluorescent lamp is in the rectification attitude.Light tube electric voltage is by resistance R 3 R4 dividing potential drops.Diode D4, resistance R 6 and capacitor C 2 constitute the halfwave rectifier filter circuit, and the voltage ratio that generates on capacitor C 2 is in the positive peak value of light tube electric voltage.Diode D3, resistance R 5 and capacitor C 4 constitute another halfwave rectifier filter circuit, and the voltage ratio that generates on capacitor C 4 is in the negative peak value of light tube electric voltage.Positive voltage on the capacitor C 2 is made positive charge by 7 pairs of capacitor C 3 of resistance R, and the negative voltage on the capacitor C 4 is done reverse charging by 8 pairs of capacitor C 3 of resistance R, and the voltage signal on the capacitor C 3 is delivered to control circuit IC.Control circuit IC makes comparisons this voltage and reference voltage, to judge whether doing rectifying effect protection action.In circuit, the resistance of resistance R 5 and R6 is identical, and the resistance of resistance R 7 and R8 is identical.
When the complete operate as normal of fluorescent tube rectifying effect do not occur, the positive negative part of alternating current that flows through fluorescent tube was identical, and the fluorescent tube forward is also identical with the equivalent resistance R1 and the R2 of reverse operation, thereby also symmetry fully of the positive negative part of modulating voltage.Modulating voltage equals the negative voltage that generates at the positive voltage that generates on the capacitor C 2 on capacitor C 4 after dividing potential drop, halfwave rectifier and filtering, resistance R 7 is identical with R8, thereby the volt that equals zero of the voltage on the capacitor C 3.In control circuit IC, set positive and negative two comparative voltages.Because the voltage on the capacitor C 3 is no more than positive and negative comparative voltage, control circuit IC does not produce the failure of oscillation signal, and electric ballast works on.
When rectifying effect occurring, fluorescent tube equivalent resistance R1 and R2 are inequality, have occurred flip-flop in the lamp current when fluorescent tube is aging, and the positive negative part of modulating voltage is also asymmetric simultaneously.Modulating voltage after halfwave rectifier and the filtering, is not equal to the negative voltage that on capacitor C 4 generate at the positive voltage that generates on the capacitor C 2 through dividing potential drop, thereby the voltage on the capacitor C 3 is not equal to zero volt.This voltage may be for just, also may be for negative, and which was higher for the positive and negative amplitude of light tube electric voltage when this depended on the rectification attitude.Voltage on C3 is for just; and be higher than among the control circuit IC when comparative voltage; perhaps the voltage on C3 is for negative; and when being lower than the negative value comparative voltage among the control circuit IC; control circuit IC is judged as fluorescent tube and is in the rectification attitude, produces corresponding failure of oscillation signal, and electric ballast quits work; thereby avoided the filament electrode superheating phenomenon, reached the rectifying effect defencive function.
When tube load need be realized isolation on electric with electric ballast, this protective circuit was seen Fig. 3, and V is a square-wave signal source among the figure, and L and C1 are series resonance inductance and electric capacity, and TX is an output transformer.R1, D1, R2 and D2 constitute the fluorescent tube equiva lent impedance, and when fluorescent tube did not have rectifying effect, the resistance of R1 and R2 equated that when rectifying effect appearred in fluorescent tube, the resistance of R1 and R2 was unequal.Resistance R 3, R4, R5, R6, R7, R8, capacitor C 2, C3, C4, diode D3, D4, these elements have formed fluorescent lamp rectifying effect testing circuit, and detected signal is delivered to the EOL input of control circuit IC.
The operation principle of this circuit is the asymmetry by the positive and negative amplitude that detects the lamp AC voltage drop equally, thereby judges whether fluorescent lamp is in the rectification attitude.Its concrete description is identical with aforesaid circuit.
The advantage of the utility model protective circuit is: the first, and in the circuit output transformer can be set, thereby simplify circuit structure, reduced the cost of electric ballast.The second, set the voltage ratio of resistance R 3 and R4 neatly, can judge the order of severity of rectifying effect quantitatively, so that accurately set the trigger voltage signal amplitude of rectifying effect defencive function.This means that protective circuit also can be discerned exactly when faint rectifying effect appears in fluorescent tube.The 3rd, output transformer can be set, thereby realize the strictness isolation on electric of fluorescent tube and electric ballast, enlarged the range of application of the utility model in electric ballast.This shows, compare with existing this type of protective circuit, the utility model flexible design, cost is low, and applicability is wide.
Electric ballast structured flowchart with the utility model rectifying effect defencive function is seen Fig. 4; 1 is the electric ballast inverter circuit among the figure; the 2nd, fluorescent lamp; the 3rd, light tube electric voltage positive peak sample circuit; the 4th, light tube electric voltage negative peak sample circuit; the 5th, positive and negative peak voltage signal adder circuit, the 6th, absolute value comparator circuit, the 7th, failure of oscillation control circuit.What be made up of 3,4,5 parts is exactly rectifying effect protective circuit described in the invention.
Fig. 1 is the structure of rectifying effect protective circuit in the prior art.
Fig. 2 is the structure of the utility model rectifying effect protective circuit.
Fig. 3 is the structure of the utility model rectifying effect protective circuit.
Fig. 4 is the electric ballast structured flowchart with the utility model defencive function.
Embodiment of the present utility model: get the components and parts of following numerical value, connect a rectifying effect protective circuit by Fig. 2 mode.R1＝200 R3＝200k?R5＝200k R7＝100k?D1＝1n4937?D3＝1n4148R2＝250 R4＝40k R6＝200k R8＝100k?D2＝1n4937?D4＝1n4148C1＝5600pf L＝1mHC2＝1000pf C3＝1000pf C4＝1000pf
Claims (3)
1. the structure of electronic ballast for fluoresent lamp rectifying effect protective circuit; by light tube electric voltage positive peak sample circuit; light tube electric voltage negative peak sample circuit; positive and negative peak voltage signal adder circuit is formed; it is characterized in that the fluorescent tube 2 that is connected with electric ballast 1; be connected with light tube electric voltage positive peak sample circuit 3, light tube electric voltage negative peak sample circuit 4 respectively; positive and negative peak value sampling circuit is connected with positive and negative crest voltage adder circuit; signal plus circuit is connected with absolute value comparator 6, connects control failure of oscillation circuit at last.
2. the structure of electronic ballast for fluoresent lamp rectifying effect protective circuit according to claim 1; it is characterized in that square-wave signal source V; series resonance inductance L and capacitor C 1 are connected the fluorescent lamp circuit two ends; R1, D1, R2, D2 constitute the fluorescent tube equiva lent impedance; testing circuit is by resistance R 3, R4, R5, R6, R7, R8; capacitor C 2, C3, C4 and diode D3, D4 constitute, and connected mode such as Fig. 2, detected signal are connected to the EOL input of control circuit IC.
3. the structure of electronic ballast for fluoresent lamp rectifying effect protective circuit according to claim 2 is characterized in that being connected to output transformer TX between series resonance inductance capacitance and fluorescent lamp.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 01246314 CN2492037Y (en) | 2001-07-03 | 2001-07-03 | Structure of rectifying effect protective circuit for fluorescent lamp electronic ballast |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 01246314 CN2492037Y (en) | 2001-07-03 | 2001-07-03 | Structure of rectifying effect protective circuit for fluorescent lamp electronic ballast |
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| Publication Number | Publication Date |
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| CN2492037Y true CN2492037Y (en) | 2002-05-15 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN 01246314 Expired - Fee Related CN2492037Y (en) | 2001-07-03 | 2001-07-03 | Structure of rectifying effect protective circuit for fluorescent lamp electronic ballast |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100356820C (en) * | 2002-12-25 | 2007-12-19 | 飞宏电子（上海）有限公司 | Fluorescent light life stop protective circuit |
| CN101534597A (en) * | 2009-01-21 | 2009-09-16 | 深圳市力诚照明电器有限公司 | Electron ballast abnormality protective circuit |
| CN1617646B (en) * | 2004-11-19 | 2010-05-12 | 东阳得邦照明有限公司 | Protective circuit while no lamp tube cut-in in electronic ballast |
| CN102508433A (en) * | 2011-11-06 | 2012-06-20 | 北京航空航天大学 | Method for compensating digital control delay of magnetic bearing switch power amplifier |
| CN101754549B (en) * | 2009-11-23 | 2012-12-12 | 宁波凯耀电器制造有限公司 | Protective circuit of electronic ballast |
-
2001
- 2001-07-03 CN CN 01246314 patent/CN2492037Y/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100356820C (en) * | 2002-12-25 | 2007-12-19 | 飞宏电子（上海）有限公司 | Fluorescent light life stop protective circuit |
| CN1617646B (en) * | 2004-11-19 | 2010-05-12 | 东阳得邦照明有限公司 | Protective circuit while no lamp tube cut-in in electronic ballast |
| CN101534597A (en) * | 2009-01-21 | 2009-09-16 | 深圳市力诚照明电器有限公司 | Electron ballast abnormality protective circuit |
| CN101754549B (en) * | 2009-11-23 | 2012-12-12 | 宁波凯耀电器制造有限公司 | Protective circuit of electronic ballast |
| CN102508433A (en) * | 2011-11-06 | 2012-06-20 | 北京航空航天大学 | Method for compensating digital control delay of magnetic bearing switch power amplifier |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |