Ultralow-Loss Passive T5 Fluorescent Lamp Ballasts for Subzero Temperature Operation

Ultralow-loss passive ballasts for T5 fluorescent lamps have previously been proven to be more energy efficient than their electronic counterparts at room temperature operation. The absence of electrolytic capacitor, switched-mode circuit, and control integrated circuit makes them particularly suitable for extreme temperature conditions. This paper first describes the challenges required for low-temperature operation and frequent ignition of T5 high-efficiency lamps. Then, the design of passive inductive-capacitive (LC) ballast for T5 28-W lamps based on a physical discharge lamp model is illustrated. To reduce the blackening effects of the filaments, a bypass resistor is incorporated to each filament to avoid local hot spot formation. Frequent ignition tests have been conducted for the proposed ballast and electronic ballast to confirm the effectiveness of the bypass resistors in protecting the filaments.