Ballast circuit for high-intensity discharging lamp

Abstract

The invention relates to a high-intensity discharge lamp ballast circuit. The existing circuits are comparatively complicated and high in cost. The invention comprises an AC-DC conversion module and a DC-AC inverter circuit; wherein, the AC-DC conversion module comprises a bridge rectifier VD1, a varistor VR1, a filter inductor L1 and filter capacitors C5 and C6; the DC-AC inverter circuit comprises power bipolar transistors VT1 and VT2, a starting charge resistor R1, a starting capacitor C1, a discharge diode VD2, a bidirectional diode VD3, a high frequency capacitor C4, emitter resistors R4and R5, a bypass resistor R6, a primary coil T1a, a secondary winding T1b and a secondary winding T1c of the T1b; the primary coil T1a is connected with a ballasting inductor L4; one end of a starterS is connected with a tap of a ballasting inductor L4 and the other end of the starter is connected with the filter capacitors C5 and C6. By adopting the half-bridge inverter circuit of the bipolar transistors, the components of the ballast circuit are mature and reliable, low in cost and rich in resource.

Description

technical field [0001] The invention belongs to the technical field of control and relates to a circuit, in particular to an improved ballast circuit for high intensity discharge lamps (High Intensity Discharge Lamps, HID Lamps), in particular to a bipolar transistor half-bridge inverter circuit structure low cost electronic ballast circuit. Background technique [0002] High-intensity discharge lamps have a negative resistance effect, and the discharge resistance drops sharply with the increase of voltage, so a current limiting device must be added when working. The typical method adopts inductive ballasts in series, and the two ends of the lamp tube are connected in parallel to start-ignition circuit to realize stable operation and start. Magnetic ballasts have the advantage of being stable and reliable, but they are bulky. The electronic ballast uses a higher oscillation frequency to supply power to the discharge lamp, and the inductance impedance increases with the inc...

AI Technical Summary

Problems solved by technology

[0003] High-intensity discharge lamps have special problems such as acoustic resonance, and cannot use general energy-saving lamp ballast circuits

High-intensity discharge lamp ballast circuits are more complex than energy-saving lamp circuits. Foreign countries generally use application-specific integrated circuits and ballasts with full-bridge MOS power devices, and the corresponding costs are high.

At present, for high-intensity discharge lamps, such as electronic ballasts for xenon lamps used in automobile headlights, the additional igniter generates 25,000V trigger high voltage, which can instantly break down the hot high-pressure gas, but it also affects the life of the lamp tube; the ignition voltage is high , the requirements for line insulation are very strict, which brings difficulties to installation and use

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