학술논문
Problems with lamp current control using a PWM signal
Document Type
Conference
Author
Source
Conference Record of the 2001 IEEE Industry Applications Conference. 36th IAS Annual Meeting (Cat. No.01CH37248) Industry applications conference Industry Applications Conference, 2001. Thirty-Sixth IAS Annual Meeting. Conference Record of the 2001 IEEE. 1:499-503 vol.1 2001
Subject
Language
ISSN
0197-2618
Abstract
In electronic ballasts for fluorescent lamps, it is common to use a half-bridge inverter. If the half-bridge switches are not gated with a 1:1 ratio, a PWM signal is generated at the output of the half-bridge to drive the lamp. To filter out the DC component of the lamp drive, a coupling capacitor is used. Despite of having no DC component in the lamp current, the darkening of one end of the lamp can be observed. This is caused by a discovered nonlinear electrophoresis effect of the mercury in the lamp. To avoid this effect, a new driving scheme for the half-bridge switches is presented. It can be described as toggled duty cycle (TDC). Some properties of the TDC are discussed.