CN2150701Y

CN2150701Y - Electronic ballast

Info

Publication number: CN2150701Y
Application number: CN 93201456
Authority: CN
Inventors: 许亚夫
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-01-04
Filing date: 1993-01-04
Publication date: 1993-12-22
Anticipated expiration: 2003-01-04

Abstract

The utility model provides an electronic ballast, in which the base loop of a power switching diode is connected in series with an inductor and a capacitor, which raises the stability of the complete machine frequency and electric current. A series resonance circuit adopts two inductance coils, which reduces the temperature distribution; the both ends of a load are connected in parallel with a pressure pressure-sensitive resistor which is used to absorb the high voltage of the capacitor of the series resonance circuit. The whole circuit of the utility model has the advantages of stable frequency and current, low failure rate, long service life, etc.

Description

Electronic ballast

The utility model relates to a kind of illumination servicing unit, especially is applicable to the electric ballast of fluorescent lamp and rare earth energy-saving lamp.

Existing electric ballast generally is made of three parts: full-wave bridge rectifier circuit, senior inversion and power output circuit, load, but have many problems.As the electric ballast that Beijing Stone Co., Zengcheng, Guangdong right fruit radio factory produce, the frequency of oscillation in high-frequency inversion loop and electric current instability, the heating of series resonant circuit choke is serious, burns out easily.The output current that the high pressure requirement of some fluorescent lamp adopts withstand voltage high power switch transistor or reduces complete machine reduces the withstand voltage of power switch transistor.Problems such as the deficiency of this structure makes complete machine have failure rate height, poor stability, and useful life is short.

The purpose of this utility model just provides a kind of energy and stablizes complete machine frequency and electric current, makes the inductance uniformity of temperature profile, and it is withstand voltage to improve complete machine, increases the electric ballast of output current.

The utility model is to realize above-mentioned purpose like this: connecting respectively between power switch transistor base loop winding is connected to electric capacity, inductance, utilizes the complementarity of electric capacity, inductance frequency to play the effect of stablizing complete machine frequency and electric current.In series resonant circuit, adopt two inductance coils in the inductance coils replacement existing structure, the inductance coil temperature is risen be evenly distributed.In piezo-resistance of the electric capacity two ends of series resonant circuit access in parallel.Absorb the high pressure of this electric capacity, reduce the voltage of power switch transistor, thereby it is withstand voltage to improve complete machine, increase output current.Choose the turn ratio of suitable pulse transformer winding, higher harmonic components and excitation waveform distortion significantly reduce, and have also reduced transistorized temperature.

Fig. 1 is a circuit block diagram of the present utility model.

Fig. 2 is a schematic circuit of the present utility model.

As shown in Figure 2, radio frequency suppresses capacitor C ₁, diode VD ₁-VD ₄, filter capacitor C ₂Form full-wave bridge rectifier circuit.In the inverter circuit high-frequency generator, resistance R ₁, diode VD ₆, capacitor C ₃Form circuits for triggering.Circuits for triggering are given power switch transistor BG ₂Trigger current is provided, makes power switch transistor BG ₂At first conducting.Voltage behind the rectifying and wave-filtering passes through capacitor C ₇, load internal resistance r ₁And r ₂, inductance L ₃And L ₄, pulse transformer B winding n ₃, power switch transistor BG ₂To capacitor C ₆Charging.The winding n of pulse transformer B ₂With n ₃Anti-phase, n ₁With n ₃Homophase, resistance R ₄Play phase calibration at this.At power switch transistor BG ₂After the conducting, the winding n of transformer B ₂Induced potential make power switch transistor BG ₂Base voltage become negative, jump to cut-off state by saturation conduction.The winding n of transformer B ₁Induced potential make power switch transistor BG ₁Base potential just become power switch transistor BG ₁By ending transition is saturation conduction, at this moment capacitor C ₆Pass through capacitor C ₇, load internal resistance r ₁And r ₂, inductance L ₃And L ₄, power switch transistor BG ₁Discharge.The forward and reverse cycle of magnetic flux that causes transformer B like this changes power switch transistor BG ₁And BG ₂By bidirectional diode VD ₈In turn conducting or end makes inductance L ₃And L ₄, capacitor C ₈The series resonant circuit generation resonance of forming, capacitor C ₈The high pressure spot that the produces pipe of lighting a lamp.After fluorescent tube starts, detuning of resonant circuit, fluorescent tube is worked under rated condition, at this moment circuit C ₈It is in parallel with load to be equivalent to a resistance.

At power transistor BG ₁And BG ₂Be connected to diode VD between collector electrode and the emitter-base bandgap grading respectively ₅And VD ₇At power switch transistor BG ₁And BG ₂Energized circuit respectively and be connected with resistance R ₂And R ₃, the winding n of pulse transformer B ₁And n ₂The negative peak high voltage pulse that produces when releasing of magnetic energy by electric R ₂And R ₃Release.At power switch transistor BG ₁And BG ₂The energized circuit winding access capacitor C of connecting respectively ₄And inductance L ₁And capacitor C ₅And inductance L ₂, improved the stability of complete machine frequency and electric current.Adopt inductance L in series resonant tank ₃And L ₄Two chokes have reduced Temperature Distribution.In capacitor C ₈Two ends also are connected with Zinc-oxide piezoresistor, play the overvoltage protection effect.

The present embodiment element is chosen as follows: capacitor C ₁Get 473/630V, capacitor C ₂Get 10M/400V, capacitor C ₃Get 104/63V, capacitor C ₄And C ₅Get 474/63V, capacitor C ₆Get 332/630V, capacitor C ₇Get 473/630V, capacitor C ₈103/630V.Inductance L ₁And L ₂Inductance value be 0.03mH, inductance L ₃And L ₄Select band magnetic gap E for use ₅The choke that Ferrite Material is made is 100 circles, inductance value 0.7mH.Resistance R ₁, R ₄Be 1M Ω, resistance R ₂, R ₃Be 56 Ω, divider resistance is selected pressure sensitive voltage ZNR10K471(or NYG471 for use).Pulse transformer B selects NXO-2000(φ 10 * 6 * 5 for use) annular iron oxidation magnetic core, winding n ₁, n ₂, n ₃Be 3 circles.

Claims

1, a kind of electric ballast comprises full-wave bridge rectifier circuit, high-frequency inversion and power output circuit, load three parts, it is characterized in that the series connection of power switch transistor base loop inserts inductance (L ₁, L ₂), electric capacity (C ₄, C ₅), the load two ends piezo-resistance R that inserts in parallel ₅, series resonant tank adopts two inductance coil L ₃, L ₄

2, electric ballast according to claim 1 is characterized in that the ratio n of pulse transformer winding ₁: n ₂: n ₃=1:1:1, n ₁, n ₂, n ₃More than or equal to 1, smaller or equal to 5.