CN2473854Y

CN2473854Y - Electronic ballast

Info

Publication number: CN2473854Y
Application number: CN 01215637
Authority: CN
Inventors: 潘国锡; 赖小彪
Original assignee: FANMEI GARDEN METAL PRODUCT Co Ltd NANHAI CITY
Current assignee: FANMEI GARDEN METAL PRODUCT Co Ltd NANHAI CITY
Priority date: 2001-03-16
Filing date: 2001-03-16
Publication date: 2002-01-23
Anticipated expiration: 2011-03-16

Abstract

The utility model discloses an electronic ballast, consisting of a rectifier circuit, a half-bridge inversion circuit, a soft starting circuit, a high-frequency double pumping circuit and an abnormal protection circuit. The output end of the rectifier circuit provides working power of each circuit; the output end of the half-bridge inversion circuit is connected with the input end of the soft starting circuit; the output end of the soft starting circuit is connected with the input end of the high-frequency double pumping circuit; the output end of the high-frequency double pumping circuit is connected with the output end of the rectifier circuit; the input end of the abnormal protection circuit is connected with the output end of the half-bridge inversion circuit; the output end of the abnormal protection circuit is connected with the control end of the half-bridge inversion circuit. The utility model has a long service life and a wide voltage adaptation range.

Description

Electric ballast

The utility model relates to a kind of electric ballast that the fluorescent lamp delayed startup is lighted of controlling.

Existing electric ballast is various in style, mainly contain common bridge rectifier electrochemical capacitor filtered electrical sub-ballast, by stream filtered electrical sub-ballast, high frequency double pump electric ballast etc., the performance of these electric ballasts is all relatively poor, and fluctuation voltage accommodation is narrower, in case abnormal conditions occur, above-mentioned electric ballast damages easily, although therefore existing electric ballast cost is lower, useful life is all very short; And existing electric ballast influences and works normally usually because of self the higher-order of oscillation and power supply grid produce interference mutually.

The purpose of this utility model is to provide a kind of long service life, the electric ballast of voltage adaptation wide ranges.

For achieving the above object, the utility model comprises rectification circuit, half-bridge inversion circuit, soft starting circuit and high frequency dual-pump circuit, the output of rectification circuit provides the working power of each circuit, the output of half-bridge inversion circuit is connected with the input of soft starting circuit, the output of soft starting circuit is connected with the input of high frequency dual-pump circuit, the output of high frequency dual-pump circuit is connected with the output of rectification circuit, it is characterized in that: also comprise abnormity protection circuit, the input of this circuit is connected with the output of described half-bridge inversion circuit, and the output of this circuit is connected with the control end of described half-bridge inversion circuit; When abnormal conditions occurring, by the blocking of oscillator in the abnormity protection circuit control half-bridge inversion circuit.

Described abnormity protection circuit comprises by capacitor C 7; divider resistance R9; R10 is connected in series the sampling voltage divider that forms successively; rectifier diode D13; by resistance R 11; the differential circuit that capacitor C 12 is formed; two-way trigger tube D14; by resistance R 12; R13; the integrating circuit that capacitor C 13 is formed; controllable silicon Q3 and diode D15; one end of sampling voltage divider is the input of this abnormity protection circuit; other end ground connection; the serial connection point of divider resistance R9 and resistance R 10 is through rectifier diode D13; resistance R 11 is connected with the trigger end of two-way trigger tube D14 with the differential circuit that capacitor C 12 is formed; the output of two-way trigger tube D14 is through resistance R 12; R13 is connected with the control utmost point G of controllable silicon Q3 with the integrating circuit that capacitor C 13 is formed; the silicon controlled minus earth; the silicon controlled anode links to each other with power supply through resistance R 7; this silicon controlled anode connects the anode of diode D15 simultaneously, and the negative electrode of diode D15 is as the output of this abnormity protection circuit.

Be connected in series instantaneous overvoltage crowbar between described rectification circuit and the input ac power, this circuit is made up of fuse FU and piezo-resistance RV.

As to further improvement of the utility model, between instantaneous overvoltage crowbar and rectification circuit, be serially connected with anti-electromagnetic interference circuit, this circuit is made up of capacitor C 1 and inductance L 1, and inductance L 1 and capacitor C 1 connect into down the filter circuit of " L ".

Owing to be provided with abnormity protection circuit and instantaneous overvoltage crowbar, make it when abnormality or overvoltage misphase, can not damage electric ballast, thereby prolong useful life greatly; Also be provided with anti-electromagnetic interference circuit simultaneously, can suppress the operate as normal that interference signal in the electrical network influences electric ballast, and the electromagnetic interference that self produces of electric ballast is played algorithm, guaranteed that electrical network is not contaminated.

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

Fig. 1 is a functional-block diagram of the present utility model;

Fig. 2 is circuit theory diagrams of the present utility model.

As Fig. 1, shown in 2, the utility model is included in instantaneous overvoltage crowbar 1, anti-electromagnetic interference circuit 2, rectification circuit 3, half-bridge inversion circuit 4, abnormity protection circuit 7, soft starting circuit 5 and high frequency dual-pump circuit 6, instantaneous overvoltage crowbar 1, anti-electromagnetic interference circuit 2 and rectification circuit 3 are connected in series successively, and export the operating voltage of other circuit by the output of rectification circuit 3, the output 4 of half-bridge inversion circuit is connected with the input of soft starting circuit 5, the output of soft starting circuit 5 is connected with the input of high frequency dual-pump circuit 6, the output of high frequency dual-pump circuit 6 is connected with the output of rectification circuit 3, abnormity protection circuit 7 inputs are connected with the output of half-bridge inversion circuit 4, and the output of abnormity protection circuit 7 is connected with the control end of half-bridge inversion circuit 4; When abnormal conditions occurring, by the blocking of oscillator in the abnormity protection circuit 7 control half-bridge inversion circuits 4.This abnormity protection circuit 7 comprises by capacitor C 7; divider resistance R9; R10 is connected in series the sampling voltage divider that forms successively; rectifier diode D13; by resistance R 11; the differential circuit that capacitor C 12 is formed; two-way trigger tube D14; by resistance R 12; R13; the integrating circuit that capacitor C 13 is formed; controllable silicon Q3 and diode D15; one end of sampling voltage divider is the input of this abnormity protection circuit 7; other end ground connection; the serial connection point of divider resistance R9 and resistance R 10 is through rectifier diode D13; resistance R 11 is connected with the trigger end of two-way trigger tube D14 with the differential circuit that capacitor C 12 is formed; the output of two-way trigger tube D14 is through resistance R 12; R13 is connected with the control utmost point G of controllable silicon Q3 with the integrating circuit that capacitor C 13 is formed; the silicon controlled minus earth; the silicon controlled anode links to each other with power supply through resistance R 7; this silicon controlled anode connects the anode of diode D15 simultaneously, and the negative electrode of diode D15 is as the output of this abnormity protection circuit 7.

The operation principle of 2 pairs of circuit is described below in conjunction with the accompanying drawings: instantaneous overvoltage crowbar 1 is by fuse FU; piezo-resistance RV forms; when the abnormal voltage situation does not appear in the alternating voltage of input; not conducting of piezo-resistance RV; its resistance approximates infinity; make the electric ballast operate as normal; when alternating voltage since wrong mutually or other reasons when causing that AC-input voltage sharply increases; when surpassing the specified carrying voltage of piezo-resistance RV; the piezo-resistance value will diminish moment; increase a lot by its electric current suddenly; over insurance silk FU blow-out current value, fuse FU is blown, and has protected circuit of electronic ballast not burnt.

Anti-electromagnetic interference circuit 2 is made up of capacitor C 1 and inductance L 1, and inductance L 1 and capacitor C 1 connect into down the filter circuit of " L ".This circuit had both suppressed from Disturbance in Power Net, and the while is also also played attenuation to the electromagnetic interference that self produces of electric ballast, and was not contaminated to guarantee electrical network.

Form bridge rectifier 3 by diode D1～D4, filter circuit is made up of diode D11, D12, capacitor C 11, C12 in the high frequency dual-pump circuit.It is with former pulsating dc voltage of rectification and the less direct voltage of the superimposed formation ripple of high frequency dual-pump circuit high frequency voltage, for half-bridge inverter provides operation DC voltage.

Half-bridge inversion circuit 4 is by diode D5～D8, resistance R 1～R6, capacitor C 2～C4, switching tube Q1, Q2, and pulse transformer T and ballast coil L2 form.After energized, at first provide a base stage trigger current to make switching tube Q2 conducting, rely on pulse transformer T and inductance positive feedback coupling to set up vibration, the winding N3 of electric current through pulse transformer T arranged by resistance R 1, R4, ballast coil L2, filament f1, f2 give capacitor C 5, C6 charging.Because winding N3 and the winding N1 same-phase of impulse hunting transformer T make the base stage of switching tube Q1 sense forward bias voltage and conducting, the electric charge of capacitor C 5, the last storage of C6 discharges through switching tube Q1.Meanwhile, the winding N1 of impulse hunting transformer T is opposite with winding N2 phase place, the signal voltage of sensing on the winding N2 is opposite with original added forward bias voltage polarity, it impels switching tube Q2 to transfer cut-off state rapidly to by conducting state, finish a cycle of oscillation, makes the very fast foundation vibration of switching tube Q1, Q2.After circuit oscillation was set up, series resonance capacitor C5, C6 two ends produced very high high-frequency ac voltage, and the excitation fluorescent lamp starter is lighted.

The starting voltage of soft starting circuit 5 is by series capacitance C5, C6 dividing potential drop, and thermistor RT is in parallel with capacitor C 6.Thermistor RT is equivalent to short circuit between the lamp warming up period, preheat curent is by capacitor C 5 and thermistor RT, after thermistor RT temperature is elevated to Curie point, resistance is elevated to rapidly more than the 10M Ω, preheat curent is by capacitor C 5, C6, cause the LC series resonance immediately, apply a very high resonance potential, fluorescent tube is punctured conducting and put right in lamp tube ends.Thermistor RT is by the process of low-resistance to high resistant, and just the preheat curent process of just lighting behind the electronics emission temperature to filament pre-heating by this process, has been avoided the sputter of cathode emission material, has prolonged the life-span of fluorescent tube.

High frequency dual-pump circuit 6 comprises diode D9～D12, capacitor C 8～C11, and in the short time after energized, jumbo capacitor C 10, C11 and diode D9～D12 forms the parasitic diode capacitor filter, and electric ballast is started working.Lamp light enter steady operation after, the part of high-frequency current is returned power supply through capacitor C 8, C9, and another part through electric capacity D9, C10 and diode D10, C11 rectifying and wave-filtering, produce positive and negative two boost voltages ± Δ V, and the 100HZ pulsating direct current stack of exporting by diode D11, D12 and above-mentioned full-wave rectifying circuit respectively, form the less direct voltage of ripple, supply power voltage as half-bridge inverter, the effect that this circuit is set is in order to make lamp current crest coefficient less than 1.7, and power factor is greater than 0.93, and the index of THD reaches H level level.

Abnormity protection circuit 7 is under normal condition, because sampled signal is less, two-way trigger tube D14 does not reach its puncture voltage, so protective circuit can not be started to control, can not influence ballast work.Be linked to be and come off when aging, gas leakage, lamp and ballast appear in fluorescent tube; during abnormal conditions such as filament fusing; its power output of electric ballast will increase 1～2 times of normal value; abnormal state protection circuit obtains sampling voltage through capacitor C 7 and divider resistance R9, R10; this sampling voltage is through diode D13 rectification; puncture two-way trigger tube D14 behind the differential circuit differential; be passed to integrating circuit; thereby make controllable silicon Q3 conducting; cause triode Q1 base drive electric current can pass through controllable silicon Q3 ground connection; make the blocking of oscillator, electric ballast quits work.Treat that fluorescent tube recovers normal, disconnect primary power source after the several seconds, reclose power supply, electric ballast is operate as normal directly, can not damage when abnormality thereby reach the protection electric ballast, has prolonged the life-span of electric ballast.

Claims

1; a kind of electric ballast; comprise rectification circuit (3); half-bridge inversion circuit (4); soft starting circuit (5) and high frequency dual-pump circuit (6); the output of rectification circuit (3) provides the working power of each circuit; the output of half-bridge inversion circuit (4) is connected with the input of soft starting circuit (5); the output of soft starting circuit (5) is connected with the input of high frequency dual-pump circuit (6); the output of high frequency dual-pump circuit (6) is connected with the output of rectification circuit (3); it is characterized in that: also comprise abnormity protection circuit (7); the input of this circuit is connected with the output of described half-bridge inversion circuit (4), and the output of this circuit is connected with the control end of described half-bridge inversion circuit (4).

2; electric ballast according to claim 1; it is characterized in that: described abnormity protection circuit (7) comprises by electric capacity (C7); divider resistance (R9; R10) be connected in series the sampling voltage divider that forms successively; rectifier diode (D13); by resistance (R11); the differential circuit that electric capacity (C12) is formed; two-way trigger tube (D14); by resistance (R12; R13); the integrating circuit that electric capacity (C13) is formed; controllable silicon (Q3) and diode (D15); one end of sampling voltage divider is the input of this abnormity protection circuit; other end ground connection; the serial connection point of divider resistance (R9) and resistance (R10) is through rectifier diode (D13); resistance (R11) is connected with the trigger end of two-way trigger tube (D14) with the differential circuit that electric capacity (C12) is formed; the output of two-way trigger tube (D14) is through resistance (R12; R13) be connected with the control utmost point (G) of controllable silicon (Q3) with the integrating circuit that electric capacity (C13) is formed; the silicon controlled minus earth; the silicon controlled anode links to each other with power supply through resistance (R7); this silicon controlled anode connects the anode of diode (D15) simultaneously, and the negative electrode of diode (D15) is as the output of this abnormity protection circuit.

3, electric ballast according to claim 1 is characterized in that: be connected in series instantaneous overvoltage crowbar (1) between described rectification circuit (3) and the input ac power, this circuit is made up of fuse (FU) and piezo-resistance (RV).

4, according to claim 2 or 3 described electric ballasts; it is characterized in that: be serially connected with anti-electromagnetic interference circuit (2) between described instantaneous overvoltage crowbar (1) and the rectification circuit (3); this circuit is made up of electric capacity (C1) and inductance (L1), and inductance (L1) and electric capacity (C1) connect into down the filter circuit of " L ".