An electronic dimming ballast with a lead-lag tank operation (LLTO) having
the properties of high efficiency and low stress is introduced in this pape
r. The ballast is configured with a voltage-fed half-bridge series-resonant
parallel-loaded inverter (SRPLI) acting as a lamp driver, It is loaded wit
h resonant tanks which are designed and operated to be capacitive and induc
tive to theoretically achieve both zero-voltage switching (ZVS) and zero-cu
rrent switching (ZCS) and to eliminate the reactive current circulating thr
ough the switches, resulting in low switching and conduction losses. Moreov
er, the merit of a successive lamp ignition can be attained with the propos
ed operation scheme so that current stress imposed on the switches can be r
educed, With the plasma model of fluorescent lamps, the analysis, operating
principle, and dimming control strategy of the electronic ballast are desc
ribed in detail. On the other hand, the limitations of the proposed scheme
are pointed out. Computer simulation results and experimental measurements
are used to verify the theoretical prediction and analytical discussion.