Filament preheating circuit of electronic ballast for fluorescent lamp

摘要

The present invention relates to a filament preheating technology of an electronic ballast for fluorescent lamps. In the conventional ballast circuit, the blackening phenomenon is caused because the filament of the fluorescent lamp is started by a high starting voltage without undergoing sufficient preheating process. There was a defect that the life of the lamp is shortened and the efficiency is lowered.;Therefore, in order to solve this problem, in the electronic ballast circuit for a fluorescent lamp, clamping the voltage supplied to the fluorescent lamp 24 at a predetermined level in an initial state where the DC power supply (V _DC ) starts to be supplied. A preheating time setting unit 25 generating a control signal for a preset time; It is configured to include a starting voltage clamping unit 26 is driven by a control signal output from the preheating time setting unit 25 to clamp the voltage supplied to the fluorescent lamp 24 to a predetermined level.