A novel parallel-resonant programmed start electronic ballast

HF Multiresonant Electronic Ballast for Fluorescent Lamps With Constant Filament Preheat Voltage

“…2) having the following design parameters: The output VA characteristic (Fig. 5) was calculated by (22), taking into account (1), (2), and (23)-(25), and was measured experimentally. Good agreement was found between the measured and calculated results (Fig.…”

“…Two fundamentally different drivers could be used for filament preheating: a current or a voltage source [2]. An example of the current source approach is the series-parallel resonant converter topology used in many commercial HF electronic ballasts ( Fig.…”

“…In that case, the filament voltage-source drive was realized by an auxiliary converter running during the preheat period. Another important feature of the ballast proposed in [2] 2)]. This was accomplished by turning off the main push-pull power inverter during the preheat period.…”

“…The push-pull configuration presented in [2] has two main drawbacks: 1) the relatively high-voltage stresses on the main power switches (about π/2 times the bus voltage) and 2) the need for an extra inverter for filament preheat. Similarly, the independent filament heating circuit presented in [6], which is connected to the center point of the half bridge, also requires a second inverter that increases the cost of the ballast.…”

HF multiresonant electronic ballast for fluorescent lamps with constant filament preheat voltage

“…This approach was investigated in [2], where a push-pull topology was proposed. In that case, the filament voltage-source drive was realized by an auxiliary converter running during the preheat period.…”