KR970061014A - Electronic ballast for fluorescent lamps - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ballast for an electronic fluorescent lamp, and more particularly, to a ballast for an electronic fluorescent lamp that can improve the power factor and prevent blackening phenomenon with a simple circuit configuration.

The ballast includes a full-wave rectifying circuit (3) for outputting a pulsating voltage from an AC input voltage, a voltage dividing / smoothing circuit (5) for generating a divided output and a smooth output of the pulsating voltage, And a resonance circuit (11) for applying a high voltage to both ends of the fluorescent lamp. The resonance circuit is connected to the primary side winding (N1) An oscillation transformer T3 having first and second secondary side windings N2 and N3 to which a voltage of the first and second secondary side windings N2 and N3 is induced; An inverter (7) composed of a pair of first and second transistors (FET1, FET2) which are alternately made conductive and in which a connection point (CN2) of the pair of transistors is connected to a primary side winding of the oscillation transformer, Lt; RTI ID = 0.0 > And trigger means (7) for applying a part of the smoothed output to the first transistor.

Description

Electronic ballast for fluorescent lamps

Since this is a trivial issue, I did not include the contents of the text.

FIG. 1 is a detailed circuit diagram of an electronic fluorescent lamp ballast according to the present invention. FIG.

Claims (3)

A full-wave rectifying circuit (3) for outputting a pulsating voltage from an AC input voltage; A partial pressure / smoothing circuit (5) for generating a divided output and a smoothed output of the pulsating voltage; A fluorescent lamp (LP1) to which the divided voltage output is applied to one terminal; A resonance circuit 11 for applying a high voltage to both ends of the fluorescent lamp; An oscillation having first and second secondary side windings N2 and N3 connected to the resonance circuit by a primary side winding N1 and having a voltage of a different polarity on a secondary side in accordance with a voltage applied to the primary side winding, A transformer T3; And a pair of first and second transistors (FET1 and FET2) alternately conducting in response to a voltage signal of an opposite polarity induced in the first and second secondary side windings of the oscillation transformer, CN2) is connected to the primary winding of the oscillation transformer; And trigger means (7) for applying a part of said smoothed output to said first transistor to start said inverter in an initial state. ≪ Desc / Clms Page number 13 > 2. The power amplifier according to claim 1, wherein the voltage divider / smoothing circuit (5) comprises: an inductor (T1) connected to the full wave rectifying circuit; A capacitor type voltage divider circuit 51 connected to the inductor, a pair of reverse diode diodes D4 and D3 connected to the voltage divider circuit, and a smoothing capacitor CP1 having both ends connected to the reverse diode. A limiting device for an electronic fluorescent lamp. The differential amplifier circuit according to claim 1, wherein the trigger circuit comprises a resistor voltage divider circuit (R1, R2), a capacitor (C6) connected between the resistor voltage divider circuit and the connection point (CN2) And a diode DA1 connected to the diode DA1. ※ Note: It is disclosed by the contents of the first application.